TY - JOUR
T1 - Probing decaying heavy dark matter with the 4-year IceCube HESE data
AU - Bhattacharya, Atri
AU - Esmaili, Arman
AU - Palomares-Ruiz, Sergio
AU - Sarcevic, Ina
N1 - Funding Information:
AB expresses gratitude to Jean-RenéCudell for helpful discussions and to support from the Fonds de la Recherche Scientifique-FNRS, Belgium, under grant No. 4.4501.15. AB is also thankful to the computational resource provided by Consortium des É quipements de Calcul Intensif (CÉCI), funded by the Fonds de la Recherche Scientifique de Belgique (F.R.S.-FNRS) under Grant No. 2.5020.11 where a part of the computation was carried out. AE thanks the computing resource provided by CCJDR, of IFGW-UNICAMP with resources from FAPESP Multi-user Project 09/54213-0. AE thanks the partial support by the CNPq fellowship No. 310052/2016-5. SPR is supported by a Ramón y Cajal contract, by the Spanish MINECO under grants FPA2014-54459-P and SEV-2014-0398, by the Generalitat Valenciana under grant PROMETEOII/2014/049 and by the European Union’s Horizon 2020 research and innovation program under the Marie Sk lodowska-Curie grant agreements No. 690575 and 674896. SPR is also partially supported by the Portuguese FCT through the CFTP-FCT Unit 777 (PEst-OE/FIS/UI0777/2013). IS was supported in part by the Department of Energy under Grant DE-FG02-13ER41976 (DE-SC0009913). SPR and IS would like to thank the Aspen Center for Physics, where this work was initiated, for its hospitality and support by the National Science Foundation grant PHY-1066293.
Publisher Copyright:
© 2017 IOP Publishing Ltd and Sissa Medialab.
PY - 2017
Y1 - 2017
N2 - After the first four years of data taking, the IceCube neutrino telescope has observed 54 high-energy starting events (HESE) with deposited energies between 20 TeV and 2 PeV . The background from atmospheric muons and neutrinos is expected to be of about 20 events, all below 100 TeV, thus pointing towards the astrophysical origin of about 8 events per year in that data set. However, their precise origin remains unknown. Here, we perform a detailed analysis of this event sample (considering simultaneously the energy, hemisphere and topology of the events) by assuming two contributions for the signal events: an isotropic power-law flux and a flux from decaying heavy dark matter. We fit the mass and lifetime of the dark matter and the normalization and spectral index of an isotropic power-law flux, for various decay channels of dark matter. We find that a significant contribution from dark matter decay is always slightly favored, either to explain the excess below 100 TeV, as in the case of decays to quarks or, as in the case of neutrino channels, to explain the three multi-PeV events. Also, we consider the possibility to interpret all the data by dark matter decays only, considering various combinations of two decay channels. We show that the decaying dark matter scenario provides a better fit to HESE data than the isotropic power-law flux.
AB - After the first four years of data taking, the IceCube neutrino telescope has observed 54 high-energy starting events (HESE) with deposited energies between 20 TeV and 2 PeV . The background from atmospheric muons and neutrinos is expected to be of about 20 events, all below 100 TeV, thus pointing towards the astrophysical origin of about 8 events per year in that data set. However, their precise origin remains unknown. Here, we perform a detailed analysis of this event sample (considering simultaneously the energy, hemisphere and topology of the events) by assuming two contributions for the signal events: an isotropic power-law flux and a flux from decaying heavy dark matter. We fit the mass and lifetime of the dark matter and the normalization and spectral index of an isotropic power-law flux, for various decay channels of dark matter. We find that a significant contribution from dark matter decay is always slightly favored, either to explain the excess below 100 TeV, as in the case of decays to quarks or, as in the case of neutrino channels, to explain the three multi-PeV events. Also, we consider the possibility to interpret all the data by dark matter decays only, considering various combinations of two decay channels. We show that the decaying dark matter scenario provides a better fit to HESE data than the isotropic power-law flux.
KW - dark matter theory
KW - neutrino astronomy
KW - neutrino detectors
KW - ultra high energy photons and neutrinos
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U2 - 10.1088/1475-7516/2017/07/027
DO - 10.1088/1475-7516/2017/07/027
M3 - Article
AN - SCOPUS:85029233591
VL - 2017
JO - Journal of Cosmology and Astroparticle Physics
JF - Journal of Cosmology and Astroparticle Physics
SN - 1475-7516
IS - 7
M1 - 027
ER -