Long-lived staus from cosmic rays

Abstract

The collision of a high energy cosmic ray with a nucleon in the upper atmosphere could produce long-lived heavy particles. Such particles would be very penetrating, since the energy loss in matter scales as the inverse mass, and could reach a neutrino telescope like IceCube from large zenith angles. Here we study this possibility and focus on the long-lived stau of SUSY models with a gravitino LSP. The signal would be a pair of muon-like parallel tracks separated by 50 meters along the detector. We evaluate the background of muon pairs and show that any events from zenith angles above 80 • could be explained by the production of these heavy particles by cosmic rays.

Probing new physics with long-lived charged particles produced by atmospheric and astrophysical neutrinos

“…The final flux of staus is, however, dramatically suppressed by the ratio σ NN,SUSY /σ NN,tot [84], even taking into account multiplicity effects in stau pair production or proton re-interactions. In particular, for the models we consider here, where the strongly interacting supersymmetric particles are typically much more massive than the NLSP, the combination of threshold effects and of the rapidly decreasing flux of incident primary protons leads to dramatically less optimistic predictions than those recently reported in [37]. There, the authors considered squarks and gluinos with extremely low masses (150 and 300 GeV), while the theoretically motivated benchmark models we use here feature squark and gluino masses between 600 GeV and 1 TeV.…”

Heavy neutrino decay at SHALON

“…Now, if this exotic physics includes a long-lived particle, we think that there is the potential for its discovery in cosmic ray experiments. Generically, to be detectable the particle must survive after the rest of the shower has been absorbed by the atmosphere (e.g., a long-lived gluino in horizontal air showers [23]) or the ground (a stau in neutrino telescopes [24]). In particular, a long-lived neutral particle could propagate to the center of a neutrino telescope and start there a contained shower when it decays.…”

Direct detection of Kaluza-Klein particles in neutrino telescopes

“…It also implies that ℓ (1) can be produced by the interactions of high energy neutrinos with the earth and propagate through it until reaching a detector, in very close analogy to the case of NLSP sleptons studied in Refs. [9,10,11,12,13]. We will show that interactions of high energy neutrinos (E ν > 10 5 GeV) with nucleons in the Earth will produce pairs of NLKPs.…”