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Publications (10 of 64) Show all publications
Blennow, M., Fernandez-Martinez, E., Gehrlein, J., Hernandez-Garcia, O. & Salvado, J. (2018). IceCube bounds on sterile neutrinos above 10 eV. European Physical Journal C, 78(10), Article ID 807.
Open this publication in new window or tab >>IceCube bounds on sterile neutrinos above 10 eV
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2018 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 78, no 10, article id 807Article in journal (Refereed) Published
Abstract [en]

We study the capabilities of IceCube to search for sterile neutrinos with masses above 10 eV by analyzing its nu(mu) disappearance atmospheric neutrino sample. We find that IceCube is not only sensitive to the mixing of sterile neutrinos to muon neutrinos, but also to the more elusive mixing with tau neutrinos through matter effects. The currently released 1-year data shows a mild preference, between 0.75 and 3 sigma depending on the binning and flux adopted, for non-zero sterile mixing. This hint overlaps with the favored region for the sterile neutrino interpretation of the ANITA upward shower although the null results from CHORUS and NOMAD on nu(mu) to nu(tau) oscillations in vacuum exclude this interpretation, while through a different channel and using a different energy range. At the 99% C.L. an upper bound is obtained that improves over the present Super-Kamiokande and DeepCore constraints in some parts of the parameter space. We also investigate the physics reach of the roughly 8 years of data that is already on tape as well as a forecast of 20 years data to probe the present hint or improve upon current constraints.

Place, publisher, year, edition, pages
Springer, 2018
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-237098 (URN)10.1140/epjc/s10052-018-6282-2 (DOI)000446575400003 ()2-s2.0-85054521088 (Scopus ID)
Funder
Göran Gustafsson Foundation for Research in Natural Sciences and Medicine
Note

QC 20181029

Available from: 2018-10-29 Created: 2018-10-29 Last updated: 2018-10-29Bibliographically approved
Blennow, M., Clementz, S. & Herrero-Garcia, J. (2018). The distribution of inelastic dark matter in the Sun. European Physical Journal C, 78(5), Article ID 386.
Open this publication in new window or tab >>The distribution of inelastic dark matter in the Sun
2018 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 78, no 5, article id 386Article in journal (Refereed) Published
Abstract [en]

If dark matter is composed of new particles, these may become captured after scattering with nuclei in the Sun, thermalize through additional scattering, and finally annihilate into neutrinos that can be detected on Earth. If dark matter scatters inelastically into a slightly heavier (O(10-100)keV) state it is unclear whether thermalization occurs. One issue is that up-scattering from the lower mass state may be kinematically forbidden, at which point the thermalization process effectively stops. A larger evaporation rate is also expected due to down-scattering. In this work, we perform a numerical simulation of the capture and thermalization process in order to study the evolution of the dark matter distribution. We then calculate and compare the annihilation rate with that of the often assumed Maxwell–Boltzmann distribution. We also check if equilibrium between capture and annihilation is reached. We find that, unless the mass splitting is very small (≲50keV) and/or the dark matter has a sub-dominant elastic cross section, the dark matter distribution does not reach a stationary state, it is not isothermal, annihilation is severely suppressed, and equilibrium is generally not reached. We also find that evaporation induced by down-scattering is not effective in reducing the total dark matter abundance.

Place, publisher, year, edition, pages
Springer-Verlag New York, 2018
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-229624 (URN)10.1140/epjc/s10052-018-5863-4 (DOI)000432927600001 ()2-s2.0-85047251363 (Scopus ID)
Funder
Göran Gustafsson Foundation for Research in Natural Sciences and Medicine
Note

QC 20180605

Available from: 2018-06-05 Created: 2018-06-05 Last updated: 2018-06-13Bibliographically approved
Blennow, M., Coloma, P., Fernandez-Martinez, E., Hernandez-Garcia, J. & Lopez-Pavon, J. (2017). Non-unitarity, sterile neutrinos, and non-standard neutrino interactions. Journal of High Energy Physics (JHEP) (4), Article ID 153.
Open this publication in new window or tab >>Non-unitarity, sterile neutrinos, and non-standard neutrino interactions
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2017 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 4, article id 153Article in journal (Refereed) Published
Abstract [en]

The simplest Standard Model extension to explain neutrino masses involves the addition of right-handed neutrinos. At some level, this extension will impact neutrino oscillation searches. In this work we explore the differences and similarities between the case in which these neutrinos are kinematically accessible (sterile neutrinos) or not (mixing matrix non-unitarity). We clarify apparent inconsistencies in the present literature when using different parametrizations to describe these effects and recast both limits in the popular neutrino non-standard interaction (NSI) formalism. We find that, in the limit in which sterile oscillations are averaged out at the near detector, their effects at the far detector coincide with non-unitarity at leading order, even in presence of a matter potential. We also summarize the present bounds existing in both limits and compare them with the expected sensitivities of near-future facilities taking the DUNE proposal as a benchmark. We conclude that non-unitarity effects are too constrained to impact present or near future neutrino oscillation facilities but that sterile neutrinos can play an important role at long baseline experiments. The role of the near detector is also discussed in detail.

Place, publisher, year, edition, pages
Springer, 2017
Keywords
Beyond Standard Model, Neutrino Physics
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-207671 (URN)10.1007/JHEP04(2017)153 (DOI)000400270600001 ()2-s2.0-85018388064 (Scopus ID)
Funder
EU, FP7, Seventh Framework Programme, PCIG11-GA-2012-321582EU, Horizon 2020, H2020-MSCA-ITN2015/674896-Elusives H2020-MSCA-RISE-2015/690575-InvisiblesPlus
Note

QC 20170602

Available from: 2017-06-02 Created: 2017-06-02 Last updated: 2017-11-10Bibliographically approved
Blennow, M., Clementz, S. & Herrero-Garcia, J. (2017). Self-interacting inelastic dark matter: A viable solution to the small scale structure problems. Journal of Cosmology and Astroparticle Physics, 2017(3), Article ID 048.
Open this publication in new window or tab >>Self-interacting inelastic dark matter: A viable solution to the small scale structure problems
2017 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, Vol. 2017, no 3, article id 048Article in journal (Refereed) Published
Abstract [en]

Self-interacting dark matter has been proposed as a solution to the small-scale structure problems, such as the observed flat cores in dwarf and low surface brightness galaxies. If scattering takes place through light mediators, the scattering cross section relevant to solve these problems may fall into the non-perturbative regime leading to a non-trivial velocity dependence, which allows compatibility with limits stemming from cluster-size objects. However, these models are strongly constrained by different observations, in particular from the requirements that the decay of the light mediator is sufficiently rapid (before Big Bang Nucleosynthesis) and from direct detection. A natural solution to reconcile both requirements are inelastic endothermic interactions, such that scatterings in direct detection experiments are suppressed or even kinematically forbidden if the mass splitting between the two-states is sufficiently large. Using an exact solution when numerically solving the Schrödinger equation, we study such scenarios and find regions in the parameter space of dark matter and mediator masses, and the mass splitting of the states, where the small scale structure problems can be solved, the dark matter has the correct relic abundance and direct detection limits can be evaded.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2017
Keywords
dark matter simulations, dark matter theory, particle physics - cosmology connection
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-210140 (URN)10.1088/1475-7516/2017/03/048 (DOI)2-s2.0-85016973980 (Scopus ID)
Note

QC 20170630

Available from: 2017-06-30 Created: 2017-06-30 Last updated: 2017-11-29Bibliographically approved
Blennow, M., Coloma, P., Fernández-Martnez, E., MacHado, P. A. & Zaldvar, B. (2016). Global constraints on vector-like WIMP effective interactions. Journal of Cosmology and Astroparticle Physics, 2016(4), Article ID 015.
Open this publication in new window or tab >>Global constraints on vector-like WIMP effective interactions
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2016 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, Vol. 2016, no 4, article id 015Article in journal (Refereed) Published
Abstract [en]

In this work we combine information from relic abundance, direct detection, cosmic microwave background, positron fraction, gamma rays, and colliders to explore the existing constraints on couplings between Dark Matter and Standard Model constituents when no underlying model or correlation is assumed. For definiteness, we include independent vector-like effective interactions for each Standard Model fermion. Our results show that low Dark Matter masses below 20 GeV are disfavoured at the 3 σ level with respect to higher masses, due to the tension between the relic abundance requirement and upper constraints on the Dark Matter couplings. Furthermore, large couplings are typically only allowed in combinations which avoid effective couplings to the nuclei used in direct detection experiments.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2016
Keywords
dark matter experiments, dark matter theory
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-187081 (URN)10.1088/1475-7516/2016/04/015 (DOI)000393286400013 ()2-s2.0-84963788700 (Scopus ID)
Note

QC 20160517

Available from: 2016-05-17 Created: 2016-05-17 Last updated: 2017-11-30Bibliographically approved
Blennow, M., Clementz, S. & Herrero-Garcia, J. (2016). Pinning down inelastic dark matter in the Sun and in direct detection. Journal of Cosmology and Astroparticle Physics, 2016(4), Article ID 004.
Open this publication in new window or tab >>Pinning down inelastic dark matter in the Sun and in direct detection
2016 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, Vol. 2016, no 4, article id 004Article in journal (Refereed) Published
Abstract [en]

We study the solar capture rate of inelastic dark matter with endothermic and/or exothermic interactions. By assuming that an inelastic dark matter signal will be observed in next generation direct detection experiments we can set a lower bound on the capture rate that is independent of the local dark matter density, the velocity distribution, the galactic escape velocity as well as the scattering cross section. In combination with upper limits from neutrino observatories we can place upper bounds on the annihilation channels leading to neutrinos. We find that, while endothermic scattering limits are weak in the isospin-conserving case, strong bounds may be set for exothermic interactions, in particular in the spin-dependent case. Furthermore, we study the implications of observing two direct detection signals, in which case one can halo-independently obtain the dark matter mass and the mass splitting, and disentangle the endothermic/exothermic nature of the scattering. Finally we discuss isospin violation.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2016
Keywords
dark matter experiments, dark matter theory
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-187090 (URN)10.1088/1475-7516/2016/04/004 (DOI)000393286400012 ()2-s2.0-84963705514 (Scopus ID)
Note

QC 20160517

Available from: 2016-05-17 Created: 2016-05-17 Last updated: 2017-11-30Bibliographically approved
Blennow, M., Coloma, P. & Fernandez-Martinez, E. (2016). The MOMENT to search for CP violation. Journal of High Energy Physics (JHEP) (3), Article ID 197.
Open this publication in new window or tab >>The MOMENT to search for CP violation
2016 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 3, article id 197Article in journal (Refereed) Published
Abstract [en]

In this letter, we analyze for the first time the physics reach in terms of sensitivity to leptonic CP violation of the proposed MuOn-decay MEdium baseline NeuTrino beam (MOMENT) experiment, a novel neutrino oscillation facility that would operate with neutrinos from muon decay. Apart from obtaining a sufficiently intense flux, the bottlenecks to the physics reach of this experiment will be achieving a high enough suppression of the atmospheric background and, particularly, attaining a sufficient level of charge identification. We thus present our results as a function of these two factors. As for the detector, we consider a very massive Gd-doped Water Cherenkov detector. We find that MOMENT will be competitive with other currently planned future oscillation experiments if a charge identification of at least 80 % can be achieved at the same time that the atmospheric background can be suppressed by at least a factor of ten. We also find a large synergy of MOMENT with the current generation of neutrino oscillation experiments, T2K and NOvA, which significantly enhances its final sensitivity.

Place, publisher, year, edition, pages
Springer, 2016
Keywords
CP violation, Neutrino Physics
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-185997 (URN)10.1007/JHEP03(2016)197 (DOI)000373391900006 ()2-s2.0-84962695346 (Scopus ID)
Note

QC 20160505

Available from: 2016-05-05 Created: 2016-04-29 Last updated: 2017-11-30Bibliographically approved
Wildner, E., Baussan, E., Blennow, M., Bogomilov, M., Burgman, A., Bouquerel, E., . . . Vassilopoulos, N. (2016). The Opportunity Offered by the ESSnuSB Project to Exploit the Larger Leptonic CP Violation Signal at the Second Oscillation Maximum and the Requirements of This Project on the ESS Accelerator Complex. Advances in High Energy Physics, Article ID 8640493.
Open this publication in new window or tab >>The Opportunity Offered by the ESSnuSB Project to Exploit the Larger Leptonic CP Violation Signal at the Second Oscillation Maximum and the Requirements of This Project on the ESS Accelerator Complex
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2016 (English)In: Advances in High Energy Physics, ISSN 1687-7357, E-ISSN 1687-7365, article id 8640493Article in journal (Refereed) Published
Abstract [en]

The European Spallation Source (ESS), currently under construction in Lund, Sweden, is a research center that will provide, by 2023, the world's most powerful neutron source. The average power of the proton linac will be 5 MW. Pulsing this linac at higher frequency will make it possible to raise the average total beam power to 10 MW to produce, in parallel with the spallation neutron production, a very intense neutrino Super Beam of about 0.4 GeV mean neutrino energy. This will allow searching for leptonic CP violation at the second oscillation maximum where the sensitivity is about 3 times higher than at the first. The ESS neutrino Super Beam, ESSnuSB operated with a 2.0 GeV linac proton beam, together with a large undergroundWater Cherenkov detector located at 540 km from Lund, will make it possible to discover leptonic CP violation at 5 sigma. significance level in 56% (65% for an upgrade to 2.5 GeV beam energy) of the leptonic CP-violating phase range after 10 years of data taking, assuming a 5% systematic error in the neutrino flux and 10% in the neutrino cross section. The paper presents the outstanding physics reach possible for CP violation with ESSnuSB obtainable under these assumptions for the systematic errors. It also describes the upgrade of the ESS accelerator complex required for ESSnuSB.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2016
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-198997 (URN)10.1155/2016/8640493 (DOI)000387385000001 ()2-s2.0-84994652587 (Scopus ID)
Note

QC 20170116

Available from: 2017-01-16 Created: 2016-12-22 Last updated: 2017-11-29Bibliographically approved
Blennow, M., Herrero Garcia, J. & Schwetz, T. (2015). A halo-independent lower bound on the dark matter capture rate in the Sun from a direct detection signal. Journal of Cosmology and Astroparticle Physics (5), Article ID 036.
Open this publication in new window or tab >>A halo-independent lower bound on the dark matter capture rate in the Sun from a direct detection signal
2015 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, no 5, article id 036Article in journal (Refereed) Published
Abstract [en]

We show that a positive signal in a dark matter (DM) direct detection experiment can be used to place a lower bound on the DM capture rate in the Sun, independent of the DM halo. For a given particle physics model and DM mass we obtain a lower bound on the capture rate independent of the local DM density, velocity distribution, galactic escape velocity, as well as the scattering cross section. We illustrate this lower bound on the capture rate by assuming that upcoming direct detection experiments will soon obtain a significant signal. When comparing the lower bound on the capture rate with limits on the high-energy neutrino flux from the Sun from neutrino telescopes, we can place upper limits on the branching fraction of DM annihilation channels leading to neutrinos. With current data from IceCube and Super-Kamiokande non-trivial limits can be obtained for spin-dependent interactions and direct annihilations into neutrinos. In some cases also annihilations into tau tau or bb start getting constrained. For spin-independent interactions current constraints are weak, but they may become interesting for data from future neutrino telescopes.

Keywords
dark matter theory, dark matter experiments
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:kth:diva-170700 (URN)10.1088/1475-7516/2015/05/036 (DOI)000355794800036 ()
Note

QC 20150707

Available from: 2015-07-07 Created: 2015-07-03 Last updated: 2017-12-04Bibliographically approved
Blennow, M. & Clementz, S. (2015). Asymmetric capture of Dirac dark matter by the Sun. Journal of Cosmology and Astroparticle Physics, 2015(8), Article ID 036.
Open this publication in new window or tab >>Asymmetric capture of Dirac dark matter by the Sun
2015 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, Vol. 2015, no 8, article id 036Article in journal (Refereed) Published
Abstract [en]

Current problems with the solar model may be alleviated if a significant amount of dark matter from the galactic halo is captured in the Sun. We discuss the capture process in the case where the dark matter is a Dirac fermion and the background halo consists of equal amounts of dark matter and anti-dark matter. By considering the case where dark matter and anti-dark matter have different cross sections on solar nuclei as well as the case where the capture process is considered to be a Poisson process, we find that a significant asymmetry between the captured dark particles and anti-particles is possible even for an annihilation cross section in the range expected for thermal relic dark matter. Since the captured number of particles are competitive with asymmetric dark matter models in a large range of parameter space, one may expect solar physics to be altered by the capture of Dirac dark matter. It is thus possible that solutions to the solar composition problem may be searched for in these type of models.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2015
Keywords
dark matter simulations, dark matter theory
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-175014 (URN)10.1088/1475-7516/2015/08/036 (DOI)2-s2.0-84940868751 (Scopus ID)
Note

QC 20151130

Available from: 2015-11-30 Created: 2015-10-09 Last updated: 2017-12-01Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-5948-9152

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