Neutrino probe of cosmic ray astrophysics and new physics at sub-fermi distances

We show that if the evolution of cosmic ray sources follows that of active galactic nuclei, the upper limit on the diffuse flux of tau neutrinos from the Pierre Auger Observatory marginally constrains the proton fraction at the end of the energy spectrum. We also discuss prospects to uncover new physics leptophobic interactions using future Auger data.Comment: Talk given at SUSY09, the 17th International Conference on Supersymmetry and the Unification of Fundamental Interactions, Boston 2009. To be published in the Conference Proceeding

Unmasking the ultrahigh-energy cosmic ray origin

The sharp change in slope of the ultrahigh-energy cosmic ray spectrum around 10^{9.6} GeV (the ankle), combined with evidence of a light but extragalactic component near and below the ankle which evolves to intermediate/heavy composition above, has proved exceedingly challenging to understand theoretically. Recently, we introduced a very general model in which, for a range of source conditions, photo-disintegration of ultrahigh-energy nuclei in the region surrounding the accelerator naturally accounts for the observed spectrum and composition of the entire extragalactic component, which dominates above about 10^{8.5} GeV. In this communication we review the generalities of the model and show that starburst galaxies provide a compelling source example.Comment: Based on talk given at the European Physical Society Conference on High Energy Physics (EPS-HEP), Venice, Italy 5-12 July 2017. To be published in the Conference Proceeding

The Pierre Auger Observatory: Science Prospects and Performance at First Light

The Pierre Auger Observatory is a major international effort aiming at high-statistics study of highest energy cosmic rays. A general description of the experimental set-up and overall performance of the detector at first light are presented.Comment: Contribution to the Proceedings of PASCOS '0

Neutron \beta-decay as the origin of IceCube's PeV (anti)neutrinos

Motivated by the indications of a possible deficit of muon tracks in the first three-year equivalent dataset of IceCube we investigate the possibility that the astrophysical (anti)neutrino flux (in the PeV energy range) could originate from \beta-decay of relativistic neutrons. We show that to accommodate IceCube observations it is necessary that only about 1% to 10% of the emitted cosmic rays in the energy decade 10^{8.5} \alt E_{CR}/GeV \alt 10^{9.5}$, yielding antineutrinos on Earth (10^{5.5} \alt E_{\bar \nu}/GeV \alt 10^{6.5}), are observed. Such a strong suppression can be explained assuming magnetic shielding of the secondary protons which diffuse in extragalactic magnetic fields of strength 10 \alt B/nG \alt 100 and coherence length \alt Mpc.Comment: To be published in PR

In Search for Extraterrestrial High Energy Neutrinos

In this paper we review the search for astrophysical neutrinos. We begin by summarizing the various theoretical predictions which correlate the expected neutrino flux with data from other messengers, specifically gammas and ultra-high energy cosmic rays. We then review the status and results of neutrino telescopes in operation and decommissioned, the methods used for data analysis and background discrimination. Particular attention is devoted to the challenge enforced by the highly uncertain atmospheric muon and neutrino backgrounds in relation to searches of diffuse neutrino fluxes. Next, we examine the impact of existing limits on neutrino fluxes on studies of the chemical composition of cosmic rays. After that, we show that not only do neutrinos have the potential to discover astrophysical sources, but the huge statistics of atmospheric muons can be a powerful tool as well. We end by discussing the prospects for indirect detection of dark matter with neutrino telescopes.Comment: Solicited Review Article submitted to Annual Review of Nuclear and Particle Science; 50 pages and 15 figures; the review is limited to 150 references, so many of them have been grouped. See http://www.icecube.wisc.edu/~tmontaruli/review for errata and other feature