Future ground arrays for ultrahigh-energy cosmic rays: recent updates and perspectives

Fujii, Toshihiro

doi:10.1051/epjconf/201920815004

Cited by 1 publication

(1 citation statement)

References 33 publications

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“…As far as the flux ΦpE ν q is concerned, for the isotropic case if one assumes the source of the EeV neutrinos to be the Greisen-Zatspin-Kuzmin (GZK) mechanism then in that case, following [38], for the concerned shower energy, Φ iso « 10´2 5 (GeV cm 2 s sr)´1. Otherwise, if some localized source is the origin of the EeV neutrinos, then the upper limit on such anisotropic flux would be Φ aniso « 3.2ˆ10´2 0 (GeV cm 2 s sr)´1 [39][40][41][42][43]. Thus by considering the mentioned parameters in the isotropic and anisotropic cases to get two AAEs, one should have, N « # 2.0ˆ10 2 for isotropic case, 2.0ˆ10 4 for anisotropic case.…”

Section: Explanation Of Anita Eventsmentioning

confidence: 99%

Connecting ANITA anomalous events to a nonthermal dark matter scenario

et al. 2020

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The ANtarctic Impulsive Transient Antenna (ANITA) collaboration has observed two EeVenergy, upward going events originating from below the horizon. As no standard model (SM) particles, propagating through the earth at such energy and exit angles, can give rise to the required survival probability for the observed events, several beyond standard model (BSM) proposals have come up. We propose a scenario where a Z 2 odd sector is responsible for such anomalous events. The next to lightest Z 2 odd particle or the next to lightest stable particle (NLSP), created from ultra high energy neutrino interactions with nucleons, can pass through the earth and then decay into the lightest Z 2 odd particle or the lightest stable particle (LSP) and a tau lepton. The long lived nature of the NLSP requires its coupling with the LSP to be very small, keeping the LSP out of thermal equilibrium in the early universe. The LSP can then be a non-thermal dark matter while the tau leptons produced from NLSP decay after passing through earth can explain the ANITA events. We first show that a purely non-thermal dark matter scenario can not give rise to the required event rates while a hybrid scenario where dark matter can have both thermal as well non-thermal contribution to its relic abundance, serves the purpose. * dborah@iitg.ac.in

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