Change search
Refine search result
123 1 - 50 of 150
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Algora, A.
    et al.
    de Angelis, G.
    Brandolini, F.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Menegazzo, R.
    Thomas, H. G.
    Ur, C. A.
    et al,
    Pronounced shape change induced by quasiparticle alignment2000In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 6103, no 3Article in journal (Refereed)
    Abstract [en]

    Mean lifetimes of high-spin states of Kr-74 have been determined using the Doppler-shift attenuation method. The high-spin states were studied using the Ca-40(Ca-40, alpha 2p) reaction at a beam energy of 160 MeV with the GASP gamma-ray spectrometer. The ground-state band and negative parity side band show the presence of three different configurations in terms of transitional quadrupole deformations. A dramatic shape change was found along the ground-state band after the S-band crossing. The deduced quadrupole deformation changes are well reproduced by cranked Woods-Saxon Strutinsky calculations.

  • 2.
    Andgren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    gamma-ray spectroscopy of At-1972008In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 78, no 4, p. 044328-1-044328-8Article in journal (Refereed)
    Abstract [en]

    Excited states of the extremely neutron-deficient nucleus At-197 have been studied in an in-beam experiment using the fusion-evaporation reaction Sn-118(Kr-82,p2n)At-197. gamma rays belonging to At-197 feeding the I-pi=(9/2(-)) ground state, as well as gamma rays feeding the 311-keV I-pi=(13/2(+)) isomer, decaying via the emission of gamma rays, and the 52-keV I-pi=(1/2(+)) alpha-decaying isomer have been identified using the recoil-alpha-decay tagging technique. Total Routhian surface calculations predict a near-spherical shape for the (9/2(-)) ground state and oblate shapes with beta(2) around -0.2 for the (1/2(+)) and the (13/2(+)) states. These predictions agree with our experimental findings.

  • 3.
    Andgren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    et al.,
    Excited states in the neutron-deficient nuclei Rn-197,Rn-199,Rn-2012008In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 77, no 5, p. 054303-1-054303-7Article in journal (Refereed)
    Abstract [en]

    Excited states of the extremely neutron-deficient radon isotopes with N = 111, 113, 115 have been studied for the first time in a series of in-beam experiments performed at the Accelerator Laboratory of the University of Jyvaskyla. The reactions used were: Sn-118(Kr-82, 3n)Rn-197, Sn-120(Kr-82, 3n)Rn-199, Sm-150(Cr-52, 3n)Rn-199, and Sn-122(Kr-82, 3n)Rn-201. The gamma rays emitted from excited states in the different isotopes were identified using the recoil-alpha-decay tagging technique. The estimated cross section for the production of Rn-197(m) was 7(3) nb, which is the lowest cross section reported so far for an in-beam study. The energies of the (17/2(+)) levels built on the isomeric (13/2(+)) states in Rn-197,Rn-199,Rn-201 indicate a transition from an anharmonic vibrational structure toward a rotational structure at low spins for these nuclei. However, the transition is not as sharp as predicted by theory.

  • 4.
    Andgren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Ganioglu, Ela
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics.
    et al.,
    Low-spin collective behavior in the transitional nuclei Mo-86,Mo-882007In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, no 1, p. 014307-1-014307-9Article in journal (Refereed)
    Abstract [en]

    Low-spin structures in Mo-86,Mo-88 were populated using the Ni-58(Ar-36, x alpha yp) heavy-ion fusion-evaporation reaction at a beam energy of 111 MeV. Charged particles and gamma rays were emitted in the reactions and detected by the DIAMANT CsI ball and the EXOGAM Ge array, respectively. In addition to the previously reported low-to-medium spin states in these nuclei, new low-spin structures were observed. Angular correlation and linear polarization measurements were performed in order to unambiguously determine the spins and parities of intensely populated states in Mo-88. Quasiparticle Random Phase Approximation (QRPA) calculations were performed for the first and second excited 2(+) states in Mo-86 and Mo-88. The results are in qualitative agreement with the experimental results, supporting a collective interpretation of the low-spin states for these transitional nuclei.

  • 5. Andreyev, A. N.
    et al.
    Ackermann, D.
    Cagarda, P.
    Gerl, J.
    Hessberger, F. P.
    Hofmann, S.
    Huyse, M.
    Keenan, A.
    Kettunen, H.
    Kleinbohl, A.
    Lavrentiev, A.
    Leino, M.
    Lommel, B.
    Matos, M.
    Munzenberg, G.
    Moore, C. J.
    O'Leary, C. D.
    Page, R. D.
    Reshitko, S.
    Saro, S.
    Schlegel, C.
    Shaffner, H.
    Taylor, M. J.
    Van Duppen, P.
    Weissman, L.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    New microsecond isomers in Bi-189,Bi-1902001In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 10, no 2, p. 129-133Article in journal (Refereed)
    Abstract [en]

    New microsecond isomers in the neutron-deficient isotopes Bi-189g,Bi-190 have been identified after in-flight separation by the velocity filter SHIP. The evaporation residues were identified on the basis of delayed recoil-gamma /X-ray, recoil-gamma /X-ray-alpha and excitation function measurements. The systematics of the [pi 1i(13/2)]13/2(+) excited states in the odd-mass Bi nuclei is discussed.

  • 6. Andreyev, A. N.
    et al.
    Ackermann, D.
    Hessberger, F. P.
    Heyde, K.
    Hofmann, S.
    Huyse, M.
    Karlgren, Daniel
    KTH, Superseded Departments, Physics.
    Kojouharov, I.
    Kindler, B.
    Lommel, B.
    Munzenberg, G.
    Page, R. D.
    de Vel, K. V.
    Van Duppen, P.
    Walters, W. B.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Shape-changing particle decays of Bi-185 and structure of the lightest odd-mass Bi isotopes2004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 69, no 5, p. 054308-Article in journal (Refereed)
    Abstract [en]

    Proton and alpha decay of the proton-rich nuclide Bi-185 has been restudied in more detail in the complete fusion reaction Nb-93(Mo-95, 3n)Bi-185 at the velocity filter SHIP. The observed decay pattern of Bi-185 and of the heavier odd-mass isotopes Bi-187,Bi-189,Bi-191,Bi-193 are interpreted based on potential-energy surface calculations. It is shown that the experimental systematics of the particle decays and of the excited states in these nuclei (where known) can be explained by the prolate-oblate shape co-existence at low excitation energy. The observed state in Bi-185 is proposed to be of prolate nature, which is in contrast with the previously proposed oblate interpretation.

  • 7. Andreyev, A. N.
    et al.
    Antalic, S.
    Ackermann, D.
    Franchoo, S.
    Hessberger, F. P.
    Hofmann, S.
    Huyse, M.
    Kojouharov, I.
    Kindler, B.
    Kuusiniemi, P.
    Lesher, S. R.
    Lommel, B.
    Mann, R.
    Munzenberg, G.
    Nishio, K.
    Page, R. D.
    Ressler, J. J.
    Streicher, B.
    Saro, S.
    Sulignano, B.
    Van Duppen, P.
    Wiseman, D.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    alpha-decay of the new isotope Po-187: Probing prolate structures beyond the neutron mid-shell at N=1042006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 73, no 4, p. 044324-Article in journal (Refereed)
    Abstract [en]

    The new neutron-deficient isotope Po-187 has been identified in the complete fusion reaction Ti-46+Sm-144 -> Po-187+3n at the velocity filter SHIP. Striking features of the Po-187 alpha decay are the strongly-hindered decay to the spherical ground state and unhindered decay to a surprisingly low-lying deformed excited state at 286 keV in the daughter nucleus Pb-183. Based on the potential energy surface calculations, the Po-187 ground state and the 286 keV excited state in Pb-183 were interpreted as being of prolate origin. The systematic deviation of the alpha-decay properties in the lightest odd-A Po isotopes relative to the smooth behavior in the even-A neighbors is discussed. Improved data for the decay of Bi-187(m,g) were also obtained.

  • 8. Andreyev, A. N.
    et al.
    Antalic, S.
    Huyse, M.
    Van Duppen, P.
    Ackermann, D.
    Bianco, L.
    Cullen, D. M.
    Darby, I. G.
    Franchoo, S.
    Heinz, S.
    Hessberger, F. P.
    Hofmann, S.
    Kojouharov, I.
    Kindler, B.
    Leppanen, A. P.
    Lommel, B.
    Mann, R.
    Muenzenberg, G.
    Pakarinen, J.
    Page, R. D.
    Ressler, J. J.
    Saro, S.
    Streicher, B.
    Sulignano, B.
    Thomson, J.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    alpha decay of the new isotopes Rn-193,Rn-1942006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 74, no 6, p. 064303-Article in journal (Refereed)
    Abstract [en]

    The new neutron-deficient isotopes Rn-193,Rn-194 have been identified in the complete fusion reaction Cr-52+Sm-144 -> Rn-196(*) at the velocity filter SHIP. The alpha-decay energy and half-life value of Rn-194 were determined to be E-alpha=7700(10) keV and T-1/2=0.78(16) ms, respectively. For Rn-193 the half-life of T-1/2=1.15(27) ms and two alpha lines at E-alpha 1=7685(15) keV, I-alpha 1=74(20)% and E-alpha 2=7875(20) keV, I-alpha 2=26(12)% were found. The decay pattern of Rn-193, which is substantially different from that of the heavier odd-A Rn isotopes, provides first experimental evidence for the long-predicted deformation in the very neutron-deficient Rn nuclei.

  • 9. Andreyev, A. N.
    et al.
    Huyse, M.
    Van de Vel, K.
    Van Duppen, P.
    Dorvaux, O.
    Greenlees, P.
    Helariutta, K.
    Jones, P.
    Julin, R.
    Juutinen, S.
    Kettunen, H.
    Kuusiniemi, P.
    Leino, M.
    Muikku, M.
    Nieminen, P.
    Rahkila, P.
    Uusitalo, J.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Hauschild, K.
    Le Coz, Y.
    In-beam and alpha-decay spectroscopy of Po-191 and evidence for triple shape coexistence at low energy in the daughter nucleus Pb-1872002In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 66, no 1Article in journal (Refereed)
    Abstract [en]

    Prompt gamma rays have been observed for the first time from the neutron-deficient nucleus Po-191 using the recoil-decay tagging technique at the RITU gas-filled separator. In addition improved alpha decay data have been measured for Po-191 and its daughter product Pb-187. The complementary gamma- and alpha-decay data point to the onset of oblate deformation in the light odd-mass Po nuclei by approaching the neutron midshell at N=104. The pattern of the favored and unfavored states observed on top of the 13/2(+) isomer in Po-191 indicates a change from the weak-coupling towards the strong-coupling scheme in Po-191m. In the daughter nucleus Pb-187, the 13/2(+) and 3/2(-) isomeric states become degenerate within the experimental accuracy. Evidence for triple shape coexistence at low energy has been found in the high-spin isomer in Pb-187. The results are supported by potential-energy surface calculations and by particle-plus-rotor calculations.

  • 10. Andreyev, A. N.
    et al.
    Huyse, M.
    Van Duppen, P.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto J.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Antalic, S.
    Ackermann, D.
    Franchoo, S.
    Heßberger, F. P.
    Hofmann, S.
    Kojouharov, I.
    Kindler, B.
    Kuusiniemi, P.
    Lesher, S. R.
    Lommel, B.
    Mann, R.
    Nishio, K.
    Page, R. D.
    Streicher, B.
    Šáro, Š.
    Sulignano, B.
    Wiseman, D.
    Wyss, Ramon A .
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Signatures of the Z=82 shell closure in alpha-decay process2013In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 110, no 24, article id 242502Article in journal (Refereed)
    Abstract [en]

    In recent experiments at the velocity filter Separator for Heavy Ion reaction Products (SHIP) (GSI, Darmstadt), an extended and improved set of α-decay data for more than 20 of the most neutron-deficient isotopes in the region from lead to thorium was obtained. The combined analysis of this newly available α-decay data, of which the Po186 decay is reported here, allowed us for the first time to clearly show that crossing the Z=82 shell to higher proton numbers strongly accelerates the α decay. From the experimental data, the α-particle formation probabilities are deduced following the Universal Decay Law approach. The formation probabilities are discussed in the framework of the pairing force acting among the protons and the neutrons forming the α particle. A striking resemblance between the phenomenological pairing gap deduced from experimental binding energies and the formation probabilities is noted. These findings support the conjecture that both the N=126 and Z=82 shell closures strongly influence the α-formation probability.

  • 11. Andreyev, A. N.
    et al.
    Huyse, M.
    Van Duppen, P.
    Weissman, L.
    Ackermann, D.
    Gerl, J.
    Hessberger, F. P.
    Hofmann, S.
    Kleinbohl, A.
    Munzenberg, G.
    Reschitko, S.
    Schlegel, C.
    Schaffner, H.
    Cagarda, P.
    Matos, M.
    Saro, S.
    Keenan, A.
    Moore, C. J.
    O'Leary, C. D.
    Page, R. D.
    Taylor, M. J.
    Kettunen, H.
    Leino, M.
    Lavrentiev, A.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Heyde, K.
    The discovery of a prolate-oblate-spherical shape triple of spin 0(+) states in the atomic nucleus Pb-1862001In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 682, p. 482C-486CArticle in journal (Refereed)
    Abstract [en]

    Two excited J(pi)=0(+) states in Pb-186 populated in the a-decay of Po-190 have been identified through alpha -particle/conversion electron coincidences in an experiment at the velocity filter SHIP. The parent Po-190 nuclei have been produced in the Nd-142(Cr-52,4n)Po-190 complete fusion reaction, alpha -particle energies and branching ratios have been measured and hindrance factors were deduced. The observed states have been interpreted as the band heads of the known prolate and (yet unobserved) oblate rotational bands in Pb-186.

  • 12. Antalic, S.
    et al.
    Andreyev, A. N.
    Ackermann, D.
    Bianco, L.
    Cullen, D.
    Darby, I.
    Franchoo, S.
    Heinz, S.
    Hessberger, F. P.
    Hofmann, S.
    Huyse, M.
    Kindler, B.
    Kojouharov, I.
    Leppanen, A. P.
    Lesher, S. R.
    Lommel, B.
    Mann, R.
    Muenzenberg, G.
    Nishio, K.
    Page, R. D.
    Pakarinen, J.
    Ressler, J. J.
    Saro, S.
    Streicher, B.
    Sulignano, B.
    Thomson, J.
    Van Duppen, P.
    Venhart, M.
    Wiseman, D.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    The new isotopes in Po-Rn region2007In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 38, no 4, p. 1557-1560Article in journal (Refereed)
    Abstract [en]

    This contribution reviews the results of the recent experiments at the velocity filter SHIP in GSI Darmstadt obtained in the region of neutron deficient isotopes from lead to radon. The data for new very neutron-deficient isotopes Po-187, Rn-193,Rn-194 and their decay properties are presented. The isotopes were produced and identified in the complete fusion reactions Ti-46+Sm-144 -> Po-187+3n and Cr-52+Sm-144 -> Rn-194,Rn-193+2,3n.

  • 13.
    Ban, Shufang
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Meng, J.
    Satula, W.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Nuclear symmetry energy in relativistic mean field theory2006In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 633, no 2-3, p. 231-236Article in journal (Refereed)
    Abstract [en]

    The physical origin of the nuclear symmetry energy is studied within the relativistic mean field (RMF) theory. Based on the nuclear binding energies calculated with and without mean isovector potential for several isobaric chains we confirm earlier Skyrme-Hartree-Fock result that the nuclear symmetry energy strength depends on the mean level spacing epsilon(A) and an effective mean isovector potential strength K(A). A detailed analysis of the isospin dependence of these two components contributing to the nuclear symmetry energy reveals a quadratic dependence due to the mean-isoscalar potential, similar to epsilon T-2, and, completely unexpectedly, the presence of a strong linear component similar to kappa T(T + 1 + epsilon/kappa) in the isovector potential. The latter generates a nuclear symmetry energy in RMF theory that is proportional to E-sym similar to T(T + 1) at variance to the non-relativistic calculation. The origin of the linear term in RMF theory needs to be further explored.

  • 14.
    Ban, Shufang
    et al.
    KTH, Superseded Departments, Physics. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Meng, J
    Wyss, Ramon
    KTH, Superseded Departments, Physics. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Nuclear symmetry energy for A=48 isobars in relativistic mean field theory2004In: Gaoneng wuli yu he wuli, ISSN 0254-3052, Vol. 28, p. 66-68Article in journal (Refereed)
    Abstract [en]

    Recently it was found that the nuclear symmetry energy can be directly associated with the mean level density and an iso-vector potential. In this paper, the nuclear symmetry energy is studied within the relativistic mean field (RMF) theory. The potential of the RMF theory can be separated into an isovector and isoscalar components. The nuclear binding energies in A = 48 isobaric chain calculated from RMF theory with or without the isovector terms for effective interactions PK1, NLSH, NL3, and TM1 have been used to analyze the nuclear symmetry energy in detail, i.e., mean level spacing epsilon and the effective isovector potential strength K.

  • 15. Bhagwat, A.
    et al.
    Vinas, X.
    Centelles, M.
    Schuck, P.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Microscopic-macroscopic approach for binding energies with the Wigner-Kirkwood method. II. Deformed nuclei2012In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 86, no 4, p. 044316-Article in journal (Refereed)
    Abstract [en]

    The binding energies of deformed even-even nuclei have been analyzed within the framework of a recently proposed microscopic-macroscopic model. We have used the semiclassical Wigner-Kirkwood (h) over bar expansion up to fourth order, instead of the usual Strutinsky averaging scheme, to compute the shell corrections in a deformed Woods-Saxon potential including the spin-orbit contribution. For a large set of 561 even-even nuclei with Z >= 8 and N >= 8, we find an rms deviation from the experiment of 610 keV in binding energies, comparable to the one found for the same set of nuclei using the finite range droplet model of Moller and Nix (656 keV). As applications of our model, we explore its predictive power near the proton and neutron drip lines as well as in the superheavy mass region. Next, we systematically explore the fourth-order Wigner-Kirkwood corrections to the smooth part of the energy. It is found that the ratio of the fourth-order to the second-order corrections behaves in a very regular manner as a function of the asymmetry parameter I = (N - Z)/A. This allows us to absorb the fourth-order corrections into the second-order contributions to the binding energy, which enables us to simplify and speed up the calculation of deformed nuclei.

  • 16. Bhagwat, A.
    et al.
    Vinas, X.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Schuck, P.
    WIGNER-KIRKWOOD METHOD FOR MICROSCOPIC-MACROSCOPIC CALCULATION OF BINDING ENERGIES2010In: International Journal of Modern Physics E, ISSN 0218-3013, Vol. 19, no 4, p. 747-758Article in journal (Refereed)
    Abstract [en]

    We propose to use the semi-classical Wigner-Kirkwood (h) over bar expansion to calculate shell corrections for spherical and deformed nuclei. The expansion is carried out up to fourth order in (h) over bar. A systematic study of Wigner-Kirkwood averaged energies is presented as a function of the deformation degrees of freedom. The shell corrections, along with the pairing energies obtained by using the Lipkin-Nogami scheme are used in the microscopic-macroscopic approach to calculate binding energies. The macroscopic part is obtained from a liquid drop formula with six adjustable parameters. Considering a set of 367 spherical nuclei, the liquid drop parameters are adjusted to reproduce the experimental binding energies, which yields a rms deviation of 630 keV.

  • 17. Bhagwat, A.
    et al.
    Viñas, X.
    Centelles, M.
    Schuck, P.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Recent developments in the Wigner - Kirkwood mass formula2013In: International Conference on Recent Trends in Nuclear Physics-2012 (ICRTNP-2012), 2013, p. 20-24Conference paper (Refereed)
    Abstract [en]

    The recently proposed microscopic - macroscopic model for nuclear masses, based on the shell corrections obtained by using the semi - classical Wigner - Kirkwood (WK) ℏ expansion of one body quantal partition function, has been extended to the even - even deformed nuclei. The nuclear potential is assumed to be deformed Woods - Saxon with spin - orbit contribution. The Coulomb potential is obtained by folding charge densities. The resulting partition function is expanded upto the fourth order in ℏ to obtain averaged energies. The shell corrections thus obtained along with pairing energies determined within the framework of the Lipkin - Nogami scheme constitute microscopic part of the model. The macroscopic part is obtained from a liquid drop formula, with nine adjustable parameters. These parameters are fitted by considering a large set of 561 even - even nuclei with Z ≥ 8 and N ≥ 8. The fit yields rms deviation of merely 610 keV from the corresponding experimental masses. A few applications of the mass formula are presented and discussed in this paper.

  • 18. Bhagwat, A.
    et al.
    Viñas, X.
    Centelles, M.
    Wyss, Ramon A.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Schuck, P.
    Microscopic-Macroscopic Mass Calculations with Wigner-Kirkwood expansion2011In: International EFES-IN2P3 Conference on "Many Body Correlations from Dilute to Dense Nuclear Systems", MBC 2011, ISSN 1742-6588, Vol. 321, no 1, p. 012053-Article in journal (Refereed)
    Abstract [en]

    The systematic study and calculation of ground state nuclear masses continues to be one of the active and important areas of research in nuclear physics. The present work is an attempt to determine the ground state masses of nuclei spanning the entire periodic table, using the Microscopic-Macroscopic approach. The semi-classical Wigner-Kirkwood (WK) expansion method is used to calculate shell corrections for spherical and deformed nuclei. The expansion is achieved upto the fourth order in . The shell corrections, along with the pairing energies obtained by using the Lipkin-Nogami scheme, constitute the microscopic part of the nuclear masses. The macroscopic part is obtained from a liquid drop formula with six adjustable parameters. It is shown that the Microscopic-Macroscopic mass calculation thus achieved, yields reliable description of ground state masses of nuclei across the periodic table. The present status of the WK mass calculations and the possible future perspectives are discussed.

  • 19. Bhagwat, A.
    et al.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Satuła, W.
    Meng, J.
    Gambhir, Y. K.
    Investigation of band termination in the lower fp shell within the cranked relativistic mean field model2013In: International Conference on Recent Trends in Nuclear Physics-2012 (ICRTNP 2012), 2013, p. 105-108Conference paper (Refereed)
    Abstract [en]

    The excitation energy difference (ΔE) between the terminating states built on the f7/2 n and d3/2 -1f 7/2 n+1 configurations (here, 'n' denotes the number of valence particles outside the 40Ca core and the particle hole excitation across the magic gap 20 is of proton type) in the lower fp shell are studied systematically within the framework of the cranked relativistic mean field model. The ΔE thus defined, depends predominantly on the f 7/2 - d3/2 shell gap, and its evolution as a function of neutron - proton asymmetry. The latter, in turn, depends on the isoscalar - isovector balance in the spin - orbit potential. Therefore, a systematic investigation of the difference ΔE is expected to test quantitatively the predicted shell gaps as a function of isospin. We find that: 1) the conventional NL3 parameter set over estimates the ΔE values, implying that the said shell gap is over - estimated in this parametrization and 2) the largest deviation between the calculated and the experimental values of ΔE is obtained for the nucleus with the smallest asymmetry value in the set of nuclei considered, and that the deviation decreases with increasing asymmetry, indicating that the in RMF parametrization considered, the isoscalar - isovector balance in the spin - orbit potential requires improvement. We carry out a re - fit of the RMF parameters to attempt a remedy to these two problems. We find that in addition to the binding energies and charge radii, if a constraint is put on the f7/2 - d3/2 shell gap in the fit to the Lagrangian parameters, the overall agreement of ΔE with the experiment improves significantly, without disturbing the agreement already achieved for the bulk properties of the nuclei spanning the entire periodic table. At a finer level, however, it is found that the isoscalar - isovector balance in the spin orbit interaction is required to be improved further. A detailed work in this direction is in progress.

  • 20.
    Bhagwat, Ameeya
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Vinas, X.
    Centelles, M.
    Schuck, P.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Microscopic-macroscopic approach for binding energies with the Wigner-Kirkwood method2010In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 81, no 4, p. 044321-Article in journal (Refereed)
    Abstract [en]

    The semiclassical Wigner-Kirkwood h expansion method is used to calculate shell corrections for spherical and deformed nuclei. The expansion is carried out up to fourth order in h. A systematic study of Wigner-Kirkwood averaged energies is presented as a function of the deformation degrees of freedom. The shell corrections, along with the pairing energies obtained by using the Lipkin-Nogami scheme, are used in the microscopic-macroscopic approach to calculate binding energies. The macroscopic part is obtained from a liquid drop formula with six adjustable parameters. Considering a set of 367 spherical nuclei, the liquid drop parameters are adjusted to reproduce the experimental binding energies, which yields a root mean square (rms) deviation of 630 keV. It is shown that the proposed approach is indeed promising for the prediction of nuclear masses.

  • 21. Bruce, A. M.
    et al.
    Simpson, J.
    Warner, D. D.
    Baktash, C.
    Barton, C. J.
    Bentley, M. A.
    Brinkman, M. J.
    Cunningham, R. A.
    Dragulescu, E.
    Frankland, L.
    Ginter, T. N.
    Gross, C. Y.
    Lemmon, R. C.
    MacDonald, B.
    O'Leary, C. D.
    Vincent, S. M.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Yu, C. H.
    Zamfir, N. V.
    Two-neutron alignment and shape changes in As-692000In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 6202, no 2Article in journal (Refereed)
    Abstract [en]

    The nucleus As-69 was Studied using the Ca-40(S-32,3p)As-69 reaction at a beam energy of 105 MeV. An extension of the band built on the g(9/2) orbital was observed to exhibit a band crossing at a rotational frequency of 0.511 MeV with an associated alignment of 7 (h) over bar. This alignment is interpreted as being due to a pair of g(9/2) neutrons. Total Routhian surface calculations have been carried out which confirm that the shape of this nucleus changes from oblate at low spin to a triaxial prolate shape at intermediate spin.

  • 22.
    Bäck, Torbjörn
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Lagergren, Karin
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Greenlees, P
    Jenkins, D
    Jones, P
    Joss, T
    Julin, R
    Juutinen, S
    Keenan, A
    Kettunen, H
    Kuusiniemi, P
    Leino, M
    Leppanen, P
    Muikku, M
    Nieminen, P
    Pakarinen, J
    Rahkila, P
    Uusitalo, J
    Spectroscopy of the neutron-deficient nuclide Pt-1712003In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 17, no 1, p. 1-5Article in journal (Refereed)
    Abstract [en]

    A number of previously unobserved gamma-rays emitted from the neutron-deficient nuclide Pt-171 have been identified using the recoil decay tagging technique. The level scheme has been updated using information from gamma-gamma coincidences and angular distribution measurements. To further confirm the assignments of the gamma-rays to Pt-171, the events were correlated with the alpha-decay of the daughter nucleus Os-167.

  • 23.
    Bäck, Torbjörn
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Lagergren, Karin
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Karlgren, Daniel
    KTH, Superseded Departments, Physics.
    Greenlees, P
    Jenkins, D
    Jones, P
    Joss, T
    Julin, R
    Juutinen, S
    Keenan, A
    Kettunen, H
    Kuusiniemi, P
    Leino, M
    Leppanen, P
    Muikku, M
    Nieminen, P
    Pakarinen, J
    Rahkila, P
    Uusitalo, J
    First observation of gamma-rays from the proton emitter Au-1712003In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 16, no 4, p. 489-494Article in journal (Refereed)
    Abstract [en]

    Gamma-rays from the alpha- and proton-unstable nuclide Au-171 have been observed for the first time. The gamma-rays were correlated with both a proton- and an alpha-particle decay branch, confirming that the nucleus decays by alpha and proton emission from a single (11/2(-)) state. The measurement confirms the previously determined half-lives for these particle decays but the present values are of higher precision. In addition, a longer half-life than determined in previous work was measured for the proton-unstable tentative ground state. The results are discussed in relation to structures in neighbouring nuclei and compared with a Strutinsky-type TRS calculation.

  • 24.
    Bäck, Torbjörn
    et al.
    KTH, Superseded Departments, Physics.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Cederkäll, Joakim
    KTH, Superseded Departments, Physics.
    Devlin, M
    Elson, J
    LaFosse, R
    Lerma, F
    Sarantites, G
    Clark, M
    Fallon, P
    Lee, Y
    Macchiavelli, O
    Macleod, W
    Observation of superdeformed states in Mo-881999In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 6, no 4, p. 391-397Article in journal (Refereed)
    Abstract [en]

    High-spin states in Mo-88 were studied using the GAMMASPHERE germanium detector array in conjunction with the MICROBALL CsI(TI) charged-particle detector system. Three gamma-ray cascades with dynamic moments of inertia showing similar characteristics to superdeformed rotational bands observed in the neighbouring A = 80 region have been identified and assigned to the nucleus Mo-88. The quadrupole moment of the strongest band, deduced by the Residual Doppler Shift Method, corresponds to a quadrupole deformation of beta(2) approximate to 0.6. This confirms the superdeformed nature of this band. The experimental data are interpreted in the framework of total routhian surface calculations. All three hands are assigned to two-quasi-particle proton configurations at superdeformed shape.

  • 25.
    Bäck, Torbjörn
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ghazi Moradi, Farnaz
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wadsworth, R.
    Transition probabilities near Sn-100 and the stability of the N, Z=50 shell closure2013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, no 3, p. 031306-Article in journal (Refereed)
    Abstract [en]

    Recent B(E2; 0(g.s.)(+) -> 2(1)(+)) measurements in light tin isotopes have revealed surprisingly large values relative to standard shell model predictions, generating an unexpected asymmetry in the B(E2) values with respect to the neutron midshell. This effect has triggered various speculations as to its origin, such as a possible weakening of the N, Z = 50 shell closure. Here we present new shell model calculations to investigate the origin of the observed asymmetric character of the B(E2) values in the tin isotopes. By including the effects of the neutron g(9/2) orbital below the N = 50 shell gap it is shown that Pauli blocking effects may play an important role near the N = 50 shell closure. A new set of single-particle energies and monopole interactions, fitted to the experimental data in the region, together with the isospin-dependent effective charge suggested by Bohr and Mottelson is shown to reproduce the experimental transition rate values in the Sn isotopic chain.

  • 26.
    Bäck, Torbjörn
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Moradi, Farnaz Ghazi
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wadsworth, R.
    The B(E2;0(gs)(+) -> 2(+)) systematics of Sn and Te isotopes in light of data in the light Sn region including a recent measurement in Te-108 using the combined recoil-decay-tagging-recoil-distance Doppler technique2012In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T150, p. 014003-Article in journal (Refereed)
    Abstract [en]

    An experimental technique combining the well-established alpha/p-decay-recoil-tagging method with a differential plunger has recently been successful in producing results in the neutron-deficient region near Sn-100. This experimental technique is briefly presented here and the result of a recent measurement for Te-108 is put in the context of the systematics of B(E-2) values for the Te and Sn isotopic chains. New state-of-the-art shell-model calculations are presented for the Sn data, and possible explanations for the unusually large B(E-2) values for the Sn isotopes near the N = 50 shell closure are given.

  • 27.
    Bäck, Torbjörn
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ghazi Moradi, Farnaz
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Al-Azri, H.
    Bloor, D.
    Brock, T.
    Wadsworth, R.
    Grahn, T.
    Greenlees, P. T.
    Hauschild, K.
    Herzan, A.
    Jacobsson, U.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Lopez-Martens, A.
    Nieminen, P.
    Peura, P.
    Rahkila, P.
    Rinta-Antila, S.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Uusitalo, J.
    Go, S.
    Ideguchi, E.
    Cullen, D. M.
    Procter, M. G.
    Braunroth, T.
    Dewald, A.
    Fransen, C.
    Hackstein, M.
    Litzinger, J.
    Rother, W.
    Lifetime measurement of the first excited 2(+) state in (108)Te2011In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 84, no 4, p. 041306-Article in journal (Refereed)
    Abstract [en]

    The lifetime of the first excited 2(+) state in the neutron deficient nuclide (108)Te has been measured for the first time, using a combined recoil decay tagging and recoil distance Doppler shift technique. The deduced reduced transition probability is B(E2;0(g.s.)(+) -> 2(+)) = 0.39(-0.04)(+0.05)e(2)b(2). Compared to previous experimental data on neutron deficient tellurium isotopes, the new data point constitutes a large step (six neutrons) toward the N = 50 shell closure. In contrast to what has earlier been reported for the light tin isotopes, our result for tellurium does not show any enhanced transition probability with respect to the theoretical predictions and the tellurium systematics including the new data is successfully reproduced by state-of-the-art shell model calculations.

  • 28.
    Cederwall, Bo
    et al.
    KTH, Superseded Departments, Physics.
    Bäck, Torbjörn
    KTH, Superseded Departments, Physics.
    Bark, R
    Tormanen, S
    Odegard, S
    King, L
    Simpson, J
    Page, D
    Amzal, N
    Cullen, M
    Greenlees, T
    Keenan, A
    Lemmon, R
    Cocks, C
    Helariutta, K
    Jones, M
    Julin, R
    Juutinen, S
    Kettunen, H
    Kankaanpaa, H
    Kuusiniemi, P
    Leino, M
    Muikku, M
    Rahkila, P
    Savelius, A
    Uusitalo, J
    Magierski, P
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Collective rotational-vibrational transition in the very neutron-deficient nuclei (171,172)-Pt1998In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 443, no 1-4, p. 69-76Article in journal (Refereed)
    Abstract [en]

    Excited states have been identified for the first time in very neutron deficient Pt-171.172 nuclei using the recoil-or-decay tagging technique. The ground-state band in Pt-172 has been established up to I-pi = 8+. A similar level sequence, presumably built on the I-pi = 13/2(+) state, is observed for Pt-171. The data are compared with theoretical calculations based on the mean field approach and the random phase approximation and are put into the context of the systematics of platinum isotopes. (C) 1998 Elsevier Science B.V. All rights reserved.

  • 29.
    Cederwall, Bo
    et al.
    KTH, Superseded Departments, Physics.
    Bäck, Torbjörn
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Johnson, Arne
    KTH, Superseded Departments, Physics.
    Cederkäll, Joakim
    KTH, Superseded Departments, Physics.
    Devlin, M
    Elson, J
    LaFosse, R
    Lerma, F
    Sarantites, G
    Clark, M
    Fallon, P
    Lee, Y
    Macchiavelli, O
    Macleod, W
    Favoured superdeformed states in 89TC1999In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 6, no 3, p. 251-255Article in journal (Refereed)
    Abstract [en]

    A superdeformed band consisting of a cascade of ten gamma-ray transitions has been identified and assigned to the nucleus Tc-89, close to the proton dripline. The quadrupole moment of the band (Q(t) = 6.7(-2.3)(+3.0) eb, as measured by the Residual Doppler Shift Method) as well as a large dynamic moment of inertia point to a highly elongated shape. With a relative population of approximately 15% of the gamma-ray flux in the Tc-89 exit channel, thp band is among the most intense superdeformed bands observed to date.

  • 30.
    Cederwall, Bo
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Evidence for enhanced collectivity in Te-I-Xe nuclei near the N=Z=50 double shell closure2007In: PROTON EMITTING NUCLEI AND RELATED TOPICS / [ed] Ferreira, LS; Arumugam, P, MELVILLE, USA: AMER INST PHYSICS , 2007, Vol. 961, p. 156-162Conference paper (Refereed)
    Abstract [en]

    Gamma-ray transitions have been identified for the first time in the extremely neutron-deficient T-z = 1 nuclide Xe-110 and the energies of the three lowest excited states in the ground-state band have been deduced. A level scheme has also been constructed for the proton-unbound, T-z = 3/2 nuclide I-109, exhibiting band structures built on g(7/2) and h(11/2) states in a weakly deformed, triaxial nucleus. In addition, a third band is proposed to be bui It oil a g(7/2) orbital coupled to an octupole-vibrational phonon of the Te-108 core. The results were obtained in a recoil-decay tagging experiment using the Ni-58(Fe-54,2n/p2n) reaction at a beam energy of 195 MeV. The experiment was performed using the highly efficient JUROGAM y-ray spectrometer in conjunction with the RITU gas-filled recoil separator and the GREAT focal -plane spectrometer. The results on Xe-110 establish a breaking of the normal trend of increasing first excited 2(+) and 4(+) level energies as a function of decreasing neutron number as the N = 50 major shell gap is approached for the neutron-deficient Xe isotopes. This unusual feature is suggested to be an effect of enhanced collectivity, possibly arising from isoscalar n-p interactions becoming increasingly important close to the N = Z line. Features in the low-lying levels of Te-106 and I-109, showing similar trends, are also discussed.

  • 31.
    Changizi, Sara A.
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Empirical pairing gaps, shell effects, and di-neutron spatial correlation in neutron-rich nuclei2015In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 940, p. 210-226Article in journal (Refereed)
    Abstract [en]

    The empirical pairing gaps derived from four different odd-even mass staggering formulas are compared. By performing single-j shell and multi-shell seniority model calculations as well as by using the standard HFB approach with Skyrme force we show that the simplest three-point formula δC(3)(N)=12[B(N,Z)+B(N-2,Z)-2B(N-1,Z)] can provide a good measure of the neutron pairing gap in even-N nuclei. It removes to a large extent the contribution from the nuclear mean field as well as contributions from shell structure details. It is also less contaminated by the Wigner effect for nuclei around N=Z. We also show that the strength of δC(3)(N) can serve as a good indication of the two-particle spatial correlation in the nucleus of concern and that the weakening of δC(3)(N) in some neutron-rich nuclei indicates that the di-neutron correlation itself is weak in these nuclei.

  • 32. de Angelis, G.
    et al.
    Gadea, A.
    Farnea, E.
    Isocrate, R.
    Petkov, P.
    Marginean, N.
    Napoli, D. R.
    Dewald, A.
    Bellato, M.
    Bracco, A.
    Camera, F.
    Curien, D.
    De Poli, M.
    Fioretto, E.
    Fitzler, A.
    Kasemann, S.
    Kintz, N.
    Klug, T.
    Lenzi, S.
    Lunardi, S.
    Menegazzo, R.
    Pavan, P.
    Pedroza, J. L.
    Pucknell, V.
    Ring, C.
    Sampson, J.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Coherent proton-neutron contribution to octupole correlations in the neutron-deficient Xe-114 nucleus2002In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 535, no 04-jan, p. 93-102Article in journal (Refereed)
    Abstract [en]

    Gamma ray linear polarization and picosecond lifetimes have been measured for levels in the neutron deficient nucleus Xe-114 using the EUROBALL IV spectrometer and the Cologne plunger device. The EUCLIDES Si-ball was used to improve the reaction channel selectivity. The linear polarization results have, for the first time, unambiguously determined the electromagnetic character of the dipole transitions de-exciting the negative parity level sequence, providing clear evidence for enhanced octupole collectivity. The discovery of two E3 transitions and the measurement of the lifetimes of the states depopulated by these transitions have allowed a quantitative determination of the octupole collectivity in the A approximate to 112 mass region. The large measured B(E3) values, close to approximate to 70 W.u., are among the strongest observed hitherto and indicate a coherent proton-neutron contribution to the octupole moment.

  • 33. Delion, D. S.
    et al.
    Liotta, R. J.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon A.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Probing shape coexistence by alpha decays to 0(+) states2014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 90, no 6, p. 061303-Article in journal (Refereed)
    Abstract [en]

    We analyze the alpha-decay fine structure to excited 0(2)(+) states in Hg and Rn isotopes. These states are described as minima in the potential energy surface (PES) provided by the standard deformed Woods-Saxon plus pairing approach. We also investigate alpha decay from the excited state P(0(2)(+)) in the parent nucleus by evaluating the corresponding hindrance factor (HF). By analyzing the experimental HF's we find the remarkable property that the ground and excited states D(0(1)(+)) and D(0(2)(+)) in the daughter nuclei are occupied with almost equal probabilities if there is no excited P(0(+)) states in the parent nucleus. Moreover, if there exists an excited state P(0(2)(+)) then the occupation probability of this state is 25%.

  • 34. Delion, D. S.
    et al.
    Liotta, Roberto J.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Alba Nova University Center, Sweden.
    Wyss, Ramon
    KTH. Alba Nova University Center, Sweden.
    Exact estimate of the alpha-decay rate and semiclassical approach in deformed nuclei2015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 5, article id 051301Article in journal (Refereed)
    Abstract [en]

    We compare the quantum mechanical procedures to estimate the total alpha-decay width from deformed nuclei in the laboratory and intrinsic systems of coordinates. Our analysis shows that the total half-life estimated in the intrinsic frame by neglecting the rotational motion of the core (adiabatic approach) is one order of magnitude smaller at beta(2) = 0.3 than the corresponding value in the spherical case. A similar calculation in the laboratory system of coordinates by considering the core motion (giving the correct theoretical estimate) predicts a reduction by only a factor of 2. The widely used "angular WKB" (Wentzel-Kramers-Brillouin) semiclassical procedure provides decay widths which are comparable to the adiabatic approach. We propose a new and very simple semiclassical "angular momentum WKB" procedure to evaluate the decay width in deformed nuclei. It provides decay widths very close to the ones obtained by the exact laboratory coupling channels procedure.

  • 35. Delion, D. S.
    et al.
    Liotta, Roberto J.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Simple approach to two-proton emission2013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, no 3, p. 034328-Article in journal (Refereed)
    Abstract [en]

    The two-proton decay process is studied by using a simple approach within the framework of scattering theory. We assume that the decaying nucleus is in a pairing state and, therefore, the two-particle wave function on the nuclear surface corresponds to the two protons moving in time-reversed states. This allows us to sustain a simplified version of the decay where the protons are simultaneously emitted with the same energies. We thus obtain a coupled system of radial equations with outgoing boundary conditions. We use similar proton-proton interactions to solve BCS equations and to describe external two-proton dynamics. A strong dependence of the pairing gap and decay width upon the proton-proton interaction strength is revealed. The experimental half-lives of Fe-45 and Ni-48 are reproduced by using a realistic proton-proton interaction.

  • 36. Delion, D. S.
    et al.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    alpha decay of high-spin isomers in superheavy nuclei2007In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, no 4, p. 044301-Article in journal (Refereed)
    Abstract [en]

    Hindrance factors corresponding to alpha decay from two quasiparticle isomeric high K states are evaluated in superheavy nuclei. We found that the hindrance factors are very sensitive to the deformations and, therefore, they may constitute a powerful tool to extract spectroscopic information in these nuclei. The hindrance factors turn out to be very large, specially for nonaligned configurations. This indicates that if one of such states is reached the parent nucleus may become isomeric. It is also possible that alpha decay may not proceed through ground state to ground state chains but rather through excited states.

  • 37. Delion, D. S.
    et al.
    Liotta, Roberto
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    High-spin proton emitters in odd-odd nuclei and shape changes2003In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 68, no 5, p. 054603-Article in journal (Refereed)
    Abstract [en]

    We present a formalism to describe proton emission from odd-odd nuclei based on a scatteringlike approach. Special emphasis is given to the case of transitions between states with different deformations. As an example we estimate the proton half-life of the odd-odd nucleus Cu-58 . Our calculations show that the change of deformation in the decay process has a significant influence on the half life. In addition, the angular momentum coupling of proton and neutron orbitals can result in an additional K hindrance of the decay. To fully account for the observed half life in Cu-58 , we propose shape mixing of the final state.

  • 38. Delion, D. S.
    et al.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Systematics of proton emission2006In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 96, no 7, p. 072501-Article in journal (Refereed)
    Abstract [en]

    A very simple formula is presented that relates the logarithm of the half-life, corrected by the centrifugal barrier, with the Coulomb parameter in proton decay processes. The corresponding experimental data lie on two straight lines which appear as a result of a sudden change in the nuclear shape marking two regions of deformation independently of the angular momentum of the outgoing proton. This feature provides a powerful tool to assign experimentally quantum numbers in proton emitters.

  • 39. Delion, D. S.
    et al.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Theories of proton emission2006In: Physics reports, ISSN 0370-1573, E-ISSN 1873-6270, Vol. 424, no 3, p. 113-174Article, review/survey (Refereed)
    Abstract [en]

    Proton emission studies are presently the focal point of nuclear structure as well as nuclear reaction investigations in rare nuclei. Theoretical approaches to investigate the properties of such nuclei by using proton emission are reviewed. We analyse time-dependent and stationary formalisms within adiabatic and non-adiabatic methods. We investigate and compare the use of resonant Gamow states within coupled channels, R-matrix and distorded wave approaches. We give a description of odd-even as well as odd-odd proton emitters using axially symmetric or triaxial potentials. The emission to excited states of the daughter nucleus and angular distribution of the emitted proton is discussed. The status of numerical applications for both spherical and deformed approaches is reviewed. The importance of proton emission in analysing the properties of nuclear matter under exotic conditions is emphasized. in the appendices we give all technical details necessary to compute the observables connected with proton emission.

  • 40. Delion, D. S.
    et al.
    Litta, R. J.
    KTH.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Decay rules in proton emission2007In: Proton Emitting Nuclei and Related Topics, American Institute of Physics (AIP), 2007, p. 47-52Conference paper (Refereed)
    Abstract [en]

    We give a simple relation, connecting the logarithm of the half-life, corrected by the centrifugal barrier, with the Coulomb parameter in proton decay processes. The reduced experimental data lie on two straight lines as a result of a sudden change in the nuclear shape, marking two regions of deformation, divided by the charge number Z = 68. This feature provides a powerful tool to assign experimentally quantum numbers in proton emitters.

  • 41.
    Delion, D. S.
    et al.
    Horia Hulubei Natl Inst Phys & Nucl Engn, Romania.
    Patial, Monika
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto J.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    A simple approach to alpha-decay fine structure2016In: Journal of Physics G: Nuclear and Particle Physics, ISSN 0954-3899, E-ISSN 1361-6471, Vol. 43, no 9, article id 095109Article in journal (Refereed)
    Abstract [en]

    We propose a simple method to evaluate alpha-transition rates to low-lying excited states in even-even nuclei. For this a realistic alpha-daughter doublefolding interaction is approximated by a parabola in the region where the decay process takes place. This allows us to evaluate the penetration probability analytically. The main experimental features of branching ratios to excited states are reproduced by this simple approach.

  • 42. Delion, D. S.
    et al.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Karlgren, Daniel
    KTH, Superseded Departments, Physics.
    Liotta, Roberto
    KTH, Superseded Departments, Physics.
    Proton emission from triaxial nuclei2004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 70, no 6, p. 061301-Article in journal (Refereed)
    Abstract [en]

    Proton decay from triaxially deformed nuclei is investigated. The deformation parameters corresponding to the mother nucleus are determined microscopically and the calculated decay widths are used to probe the mean-field wave function. The proton wave function in the mother nucleus is described as a resonant state in a coupled-channel formalism. The decay width, as well as the angular distribution of the decaying particle, are evaluated and their dependence upon the triaxial deformation parameters is studied in the decay of Re-161 and Bi-185. It is found that the decay width is very sensitive to the parameters defining the triaxial deformation while the angular distribution is a universal function which does not depend upon details of the nuclear structure.

  • 43. Delion, D. S.
    et al.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto J.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics.
    Investigations of proton-neutron correlations close to the drip line2010In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 82, no 2, p. 024307-Article in journal (Refereed)
    Abstract [en]

    Proton-neutron correlations in nuclei above the Z = 50 shell closure are investigated with the aim of understanding the behavior of the 2(+) and 4(+) states in Te and Xe isotopes, which remain at a rather constant energy as one approaches the shell closure at N = 50. Our calculations reveal that standard quasiparticle random phase approximation calculations, involving a quadrupole-quadrupole (QQ) interaction with constant strengths, cannot explain this feature. It is found that to reproduce the experimental data within this model one has to include a variable proton-neutron interaction. It turns out that an increased proton-neutron QQ interaction increases the collectivity (i.e., B(E2) values) when approaching the N = 50 region, whereas an increased proton-neutron pairing interaction decreases the collectivity. We thus conclude that the ratio between the B(E2) value and 2(+) energy is a "fingerprint" of proton-neutron collectivity and it should be determined in future experiments concerning light Te isotopes. Based on this criterion, we conclude that the available experimental data indicate an enhanced proton-neutron pairing interaction by approaching doubly magic Z = N = 20 and Z = N = 28 regions.

  • 44. Dobaczewski, J.
    et al.
    Dudek, J.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    T=0 neutron-proton pairing correlations in the superdeformed rotational bands around Zn-602003In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 67, no 3, p. 343081-3430810Article in journal (Refereed)
    Abstract [en]

    The superdeformed bands in Cu-58, Cu-59, Zn-60, and Zn-61 are analyzed within the frameworks of the Skyrme-Hartree-Fock as well as Strutinsky-Woods-Saxon total Routhian surface methods with and without T = 1 pairing correlations between like particles. It is shown that a consistent description within these standard approaches cannot be achieved. A T = 0 neutron-proton pairing configuration mixing of signature-separated bands in Zn-60 is suggested as a possible solution to the problem.

  • 45. Fischer, S. M.
    et al.
    Lister, C. J.
    Balamuth, D. P.
    Bauer, R.
    Becker, J. A.
    Bernstein, L. A.
    Carpenter, M. P.
    Durell, J.
    Fotiades, N.
    Freeman, S. J.
    Garrett, P. E.
    Hausladen, P. A.
    Janssens, R. V. F.
    Jenkins, D.
    Leddy, M.
    Ressler, J.
    Schwartz, J.
    Svelnys, D.
    Sarantites, D. G.
    Seweryniak, D.
    Varley, B. J.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Alignment delays in the N = Z nuclei Kr-72, Sr-76, and Zr-802001In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 8713, no 13Article in journal (Refereed)
    Abstract [en]

    The ground state rotational bands of the N = Z nuclei Kr-72, Sr-76, and Zr-80 have been extended into the angular momentum region where rotation alignment of particles is normally expected. By measuring the moments of inertia of these bands we have observed a consistent increase in the rotational frequency required to start pair breaking, when compared to neighboring nuclei. Kr-72 shows the most marked effect. It has been widely suggested that these delayed alignments arise from np-pairing correlations. However, alignment frequencies are very sensitive to shape degrees of freedom and normal pairing, so the new experimental observations are still open to interpretation.

  • 46. Gadea, A.
    et al.
    de Angelis, G.
    Farnea, E.
    Marginean, N.
    Nyberg, J.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    et al,
    Spectroscopy of heavy N=Z nuclei with GASP and EUROBALL2003In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 34, no 4, p. 2429-2438Article in journal (Refereed)
    Abstract [en]

    The coupling of big Ge-arrays like EUROBALL or GASP with ancillary detectors for the study of the structure properties of very exotic nuclei, far from the stability valley, has given outstanding results in the last years. A large fraction of the experiments performed with both arrays has been devoted to study both proton-rich and neutron-rich nuclei populated using stable beams provided by the LNL Legnaro and MeS Strasbourg accelerators. Nuclei lying close to the N = Z line are of particular interest being a laboratory where collective excitations as well as fundamental properties of the nuclear force can be tested, like isospin symmetry and isospin breaking terms, proton neutron pairing, dripline effects and coherent neutron and proton contributions to the nuclear excitations. Some of this properties are more evident (degree of isospin mixing) or can be only observed (collective effects) in heavy N = Z nuclei. In this contribution we present the experimental results obtained by our collaboration along and in the vicinity of N = Z line.

  • 47. Ganioglu, E.
    et al.
    Wyss, Ramon
    Magierski, P.
    Properties of N=90 isotones within the mean field perspective2014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 89, no 1, p. 014311-Article in journal (Refereed)
    Abstract [en]

    In recent years, the N = 90 isotones have been investigated to a large extent in relation to studies of quantum phase transitions. In this paper, we use the mean field approach with pairing-deformation self-consistent total Routhian surface (TRS) calculations to study the N = 90 isotones and neighboring nuclei. The important probes, such as moments of inertia, quadrupole moments, the energy ratio of E(4(1)(+))/E(2(1)(+)), and octupole and hexadecapole degrees of freedom are considered and the calculated results are compared with the available experimental data. From a microscopic point of view, the N = 90 isotones characterize the onset of the deformed region and are very well described by mean field calculations. The results are compared with those from other studies in beyond mean field approximations. Shape coexistence phenomena in the region of interest are discussed.

  • 48.
    Ganioglu, Ela
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    A systematic study in the region of N=86-982007In: Six International Conference of the Balkan Physical Union, American Institute of Physics (AIP), 2007, p. 111-112Conference paper (Refereed)
    Abstract [en]

    In this work a systematic study was performed in the region of N=86-98 by means of Total Routhian Surface (TRS) calculations. TRS calculations are based on Woods-Saxon potential in the framework of cranked shell model (CSM) and Bogolyubov-Strutinsky approach. The deformed mean field is capable of making predictions on nuclear deformations and other observables like moments of inertia and quadrupole moments. These observables are calculated for the region of interest and compared with the experimental data. The regime, in which the TRS approach can be used successfully, covers of neutron number N≥88. In particular these nuclei which are assigned to be situated at a point of phase transition, having X(5) symmetry can be described by mean field calculation.

  • 49.
    Ghazi Moradi, Farnaz
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Atac, Ayse
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Eeckhaudt, S.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Grahn, T.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Greenlees, P. T.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Jones, P. M.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Julin, R.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Juutinen, S.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Ketelhut, S.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Leino, M.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Nyman, M.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Rahkila, P.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Sarén, J.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Scholey, C.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Sorri, J.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Uusitalo, J.
    Department of Physics, University of Jyväskylä, Jyväskylä, Finland.
    Ganioglu, E.
    Science Faculty, Physics Department, Istanbul University, Istanbul, Turkey.
    Thomson, J.
    Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK.
    Joss, D. T.
    Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK.
    Page, R. D.
    Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK.
    Ertürk, S.
    CCLRC Daresbury Laboratory, Daresbury, Warrington, UK.
    Simpson, J.
    CCLRC Daresbury Laboratory, Daresbury, Warrington, UK.
    Gomez Hornillos, M. B.
    Seccio d'Enginyeria Nuclear, Universitat Politecnica de Catalunya, Barcelona, Spain.
    Bianco, L.
    Department of Physics, University of Guelph, Ontario, Canada.
    High-spin study of 162Ta2011In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 84, no 6, p. 064312-Article in journal (Refereed)
    Abstract [en]

    Excited states in the odd-odd neutron deficient nucleus (162)Ta (Z = 73, N = 89) have been studied for the first time. The gamma spectroscopy analysis using gamma - gamma - gamma coincidences revealed a strongly coupled rotational structure that was established up to large angular momentum states. The rotational band was assigned to the configuration pi h(11/2)[514]9/2 circle times nu i(13/2)[660]1/2 based on its rotational and electromagnetic properties. The data are interpreted within the framework of total Routhian surface calculations, which suggests an axially symmetric shape with a gamma-softminimum at beta(2) approximate to 0.16 and gamma approximate to 6 degrees. The crossing of the signature partners observed in heavier (N >= 91) odd-odd nuclides in this mass region is found to be absent at N = 89. This might be correlated with a change in S-band structure above the paired band crossing at these neutron numbers.

  • 50. Glowacz, S.
    et al.
    Satula, Wojtek
    KTH, Superseded Departments, Physics.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Cranking in isospace2004In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 19, no 1, p. 33-44Article in journal (Refereed)
    Abstract [en]

    The response of isovector and isoscalar pair fields to generalized rotation in isospace is studied. Analytical expressions for constant gap solutions for different limiting cases of the model are derived. In particular, the connections between gauge angles among pairing gaps and the position of the iso-cranking axis are investigated in N = Z nuclei. The two domains of collective and noncollective rotation in space are generalized to isospace. The amplitudes for pair-transfer of T = 0 and T = 1 pairs are calculated. It is shown that the structure of the T = 0 state in odd-odd nuclei prevents any enhancement of pair transfer also in the presence of strong isoscalar pairing correlations. The energy differences of the T = 0 and T = 1 excitations in odd-odd nuclei are qualitatively reproduced by Total-Routhian-Surface calculations.

123 1 - 50 of 150
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf