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Aspects of Dimensional Deconstruction and Neutrino Physics
KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
2007 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

The existence of at or curved extra spatial dimensions provides new insights into several of the problems which face the Standard Model of particle physics, including the gauge hierarchy problem, the smallness of neutrino masses, and the dark matter problem. However, higher-dimensional gauge theories are not renormalizable and can only be considered as low-energy effective theories, with limited applicability. Dimensional deconstruction provides a class of manifestly gauge invariant possible ultraviolet completions of higher-dimensional gauge theories, formulated within conventional quantum eld theory. In dimensional deconstruction, the fundamental theory is a four-dimensional quantum eld theory and extra spatial dimensions are generated dynamically at low energies. In this thesis, we study di erent applications of dimensional deconstruction in the contexts of neutrino masses, mixing and oscillations, Kaluza{Klein dark matter, and e ective eld theories for discretized higher-dimensional gravity.

A different possibility to understand the smallness of neutrino masses is provided by the see-saw mechanism. This is a genuinely four-dimensional mechanism, where the light neutrino masses are induced by the addition of heavy right-handed Majorana neutrinos or by other heavy degrees of freedom, such as scalar SU(2)L triplet elds. It has the attractive feature of simultaneously providing a mechanism for generating the observed baryon asymmetry of the Universe. We study in this context a specific left-right symmetric see-saw model.

Place, publisher, year, edition, pages
Stockholm: KTH , 2007. , x, 104 p.
Series
Trita-FYS, ISSN 0280-316X ; 2007:48
Keyword [en]
Dimensional deconstruction, higher-dimensional gauge theories, discretized gravity, neutrino mass, neutrino mixing, neutrino oscillations
National Category
Other Engineering and Technologies
Identifiers
URN: urn:nbn:se:kth:diva-4480ISBN: 978-91-7178-728-6 (print)OAI: oai:DiVA.org:kth-4480DiVA: diva2:12470
Public defence
2007-09-19, Sal F3, KTH, Lindstedtsvägen 26, Stockholm, 10:00 (English)
Opponent
Supervisors
Note
QC 20100716Available from: 2007-09-03 Created: 2007-09-03 Last updated: 2010-07-16Bibliographically approved
List of papers
1. Neutrino oscillations in deconstructed dimensions
Open this publication in new window or tab >>Neutrino oscillations in deconstructed dimensions
2005 (English)In: Journal of High Energy Physics (JHEP), ISSN 1029-8479, E-ISSN 1126-6708, Vol. 2005, no 02, 049- p.Article in journal (Refereed) Published
Abstract [en]

We present a model for neutrino oscillations in the presence of a deconstructed non-gravitational large extra dimension compactified on the boundary of a two-dimensional disk. In the deconstructed phase, sub-mm lattice spacings are generated from the hierarchy of energy scales between similar to 1 TeV and the usual B - L breaking scale similar to 10(15) GeV. Here, short-distance cutoffs down to similar to 1eV are motivated by the strong coupling behavior of gravity in local discrete extra dimensions. This could make it possible to probe the discretization of extra dimensions and non-trivial field configurations in theory spaces which have only a few sites, i.e., for coarse latticizations. Thus, the model has relevance to present and future precision neutrino oscillation experiments.

Place, publisher, year, edition, pages
IOP Publishing, 2005
Keyword
Extra Large Dimensions; Lattice Gauge Field Theories; Lattice Models of Gravity; Neutrino Physics
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-7438 (URN)10.1088/1126-6708/2005/02/049 (DOI)000228861300049 ()2-s2.0-22144474780 (Scopus ID)
Funder
Swedish Research Council, 621-2001-1611Swedish Research Council, 621-2002-3577
Note

QC 20100716

Available from: 2011-06-21 Created: 2007-09-03 Last updated: 2012-10-01Bibliographically approved
2. Indirect detection of Kaluza-Klein dark matter from latticized universal dimensions
Open this publication in new window or tab >>Indirect detection of Kaluza-Klein dark matter from latticized universal dimensions
2006 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, Vol. 2006, no 06, 014- p.Article in journal (Refereed) Published
Abstract [en]

We consider Kaluza-Klein dark matter from latticized universal dimensions. We investigate two different lattice models, where the models differ in the choice of boundary conditions. The models reproduce relevant features of the continuum model for Kaluza-Klein dark matter. For the model with simple boundary conditions, this is the case even for a model with only a few lattice sites. We study the effects of the latticization on the differential flux of positrons from annihilation of Kaluza-Klein dark matter in the galactic halo. We find that for different choices of the compactification radius, the differential positron flux rapidly converges to the continuum model results as a function of the number of lattice sites. In addition, we consider the prospects for upcoming space-based experiments such as PAMELA and AMS-02 to probe the latticization effect.

Place, publisher, year, edition, pages
IOP Publishing / SISSA, 2006
Keyword
Dark matter; Extra dimensions
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-7439 (URN)10.1088/1475-7516/2006/06/014 (DOI)000238978600014 ()2-s2.0-37649029696 (Scopus ID)
Funder
Swedish Research Council, 621-2001-1611Swedish Research Council, 621-2002-3577
Note
QC 20100716Available from: 2011-06-21 Created: 2007-09-03 Last updated: 2011-06-21Bibliographically approved
3. Discretized gravity in 6D warped space
Open this publication in new window or tab >>Discretized gravity in 6D warped space
2007 (English)In: Nuclear Physics B, ISSN 0550-3213, Vol. 278, no 1-3, 32-63 p.Article in journal (Refereed) Published
Abstract [en]

We consider discretized gravity in six dimensions. where the two extra dimensions have been compactified on a hyperbolic disk of constant curvature. We analyze different realizations of lattice gravity on the disk at the level of an effective field theory for massive gravitons. It is shown that the observed strong coupling scale of lattice gravity in discretized five-dimensional flat or warped space can be increased if the latticized fifth dimension is wrapped around a hyperbolic disk that has a non-trivial warp factor. As an application, we also study the generation of naturally small Dirac neutrino masses via a discrete volume suppression mechanism and discuss briefly collider implications of our model.

Keyword
LARGE EXTRA DIMENSIONS; COSMOLOGICAL CONSTANT; STRING THEORY; FIELD; MILLIMETER; HIERARCHY; NEUTRINOS
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:kth:diva-7440 (URN)10.1016/j.nuclphysb.2007.05.009 (DOI)000249711100002 ()2-s2.0-34548124935 (Scopus ID)
Note
QC 20100716. Uppdaterad från In press till Published 20100716.Available from: 2007-09-03 Created: 2007-09-03 Last updated: 2010-07-16Bibliographically approved
4. Stability and leptogenesis in the left-right symmetric seesaw mechanism
Open this publication in new window or tab >>Stability and leptogenesis in the left-right symmetric seesaw mechanism
Show others...
2007 (English)In: Journal of High Energy Physics (JHEP), ISSN 1029-8479, E-ISSN 1126-6708, Vol. 4, 022-1-022-25 p.Article in journal (Refereed) Published
Abstract [en]

We analyze the left-right symmetric type I+II seesaw mechanism, where an eight-fold degeneracy among the mass matrices of heavy right-handed neutrinos M-R is known to exist. Using the stability property of the solutions and their ability to lead to successful baryogenesis via leptogenesis as additional criteria, we discriminate among these eight solutions and partially lift their eight-fold degeneracy. In particular, we find that viable leptogenesis is generically possible for four out of the eight solutions.

Keyword
baryogenesis, neutrino physics
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-7250 (URN)10.1088/1126-6708/2007/04/022 (DOI)000246396400022 ()
Note
QC 20100630 QC 20110518Available from: 2011-05-18 Created: 2007-05-31 Last updated: 2011-06-15Bibliographically approved
5. Triplet leptogenesis in left-right symmetric seesaw models
Open this publication in new window or tab >>Triplet leptogenesis in left-right symmetric seesaw models
2008 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, Vol. 2008, no 01, 014- p.Article in journal (Refereed) Published
Abstract [en]

We discuss scalar triplet leptogenesis in a specific left-right symmetric seesaw model. We show that the Majorana phases that are present in the model can be effectively used to saturate the existing upper limit on the CP-asymmetry of the triplets. We solve the relevant Boltzmann equations and analyze the viability of triplet leptogenesis. It is known for this kind of scenario that the efficiency of leptogenesis is maximal if there exists a hierarchy between the branching ratios of the triplet decays into leptons and Higgs particles. We show that triplet leptogenesis typically favors branching ratios with not too strong hierarchies, since maximal efficiency can only be obtained at the expense of suppressed CP-asymmetries.

Place, publisher, year, edition, pages
IOP Publishing / SISSA, 2008
Keyword
Baryon asymmetry; Cosmology of theories beyond the SM; Neutrino properties
National Category
Subatomic Physics
Identifiers
urn:nbn:se:kth:diva-7442 (URN)10.1088/1475-7516/2008/01/014 (DOI)000252932200018 ()2-s2.0-38949145112 (Scopus ID)
Funder
Swedish Research Council, 621-2001-1611Swedish Research Council, 621-2005-3588
Note
QC 20100716. Uppdaterad från manuskript till artikel 20100716.Available from: 2011-06-21 Created: 2007-09-03 Last updated: 2011-06-21Bibliographically approved

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