R -parity violating supersymmetric explanation of the anomalous events at ANITA

Jack H Collins,Yicong Sui,P S Bhupal Dev

doi:10.1103/physrevd.99.043009

Abstract

The ANITA balloon experiment has observed two EeV-energy, upgoing events originating from well below the horizon. This is puzzling, because (i) no Standard Model (SM) particle is expected to survive passage through Earth at such energies and incident angles, and (ii) no such events were reported by IceCube. In this paper, we address both these issues by invoking a beyond SM interpretation of the EeV events as due to the decay of a long-lived bino in the R-parity violating (RPV) supersymmetry. In particular, a TeV-scale slepton/squark can be resonantly produced through the interaction of the EeV neutrino with electrons/nucleons inside Earth, that decays to a light, long-lived bino, which survives the propagation through Earth matter before decaying back to neutrinos, leptons and/or quarks, thus producing upgoing air showers in the atmosphere near ANITA. We find that the ANITA events can be explained with a GeV-scale bino and ${\cal O}(0.1)$ RPV couplings, which are consistent with all existing high and low-energy constraints. We also find that an isotropic neutrino flux is inadequate for a beyond the SM explanation of this kind, and an anisotropic flux must be invoked. Finally, we also address the apparent tension of these observations with IceCube. Various aspects of our interpretation are testable in the near future at different frontiers, such as by the LHC, Belle II, ANITA-IV and IceCube.

Highlights

The Antarctic Impulsive Transient Antenna (ANITA) Collaboration has recently reported two anomalous upward-going ultrahigh energy cosmic ray (UHECR) air shower events with deposited shower energies of 0.6 Æ 0.4 EeV and 0.56þ−00..23 EeV, respectively [1,2]
(iv) For LLE-type R-parity violating (RPV) couplings, the bino decays to a τ-lepton and electron, either of which could induce the air shower seen by ANITA, whereas for LQD-type couplings, the bino directly decays to quarks and neutrino, which mimic the standard model (SM) τ-decay
We have explored a RPV-SUSY interpretation of the two anomalous up-going air showers seen by ANITA

Summary

INTRODUCTION

The Antarctic Impulsive Transient Antenna (ANITA) Collaboration has recently reported two anomalous upward-going ultrahigh energy cosmic ray (UHECR) air shower events with deposited shower energies of 0.6 Æ 0.4 EeV and 0.56þ−00..23 EeV, respectively [1,2]. Several beyond-SM (BSM) interpretations of the ANITA anomalous events, such as sterile neutrino mixing [22,23], heavy dark matter [24,25] and stau [7,26] decays, have been discussed All of these explanations assume that the showers observed by ANITA were initiated by the hadronic decays of a τ lepton. (iv) For LLE-type RPV couplings, the bino decays to a τ-lepton (if kinematically allowed) and electron, either of which could induce the air shower seen by ANITA, whereas for LQD-type couplings, the bino directly decays to quarks and neutrino, which mimic the SM τ-decay In the latter case, there exists some parameter space for which no through-going track events are predicted at IceCube

THE MODEL SETUP

LLE contribution

EVENT RATE

ICECUBE SIGNATURES

CONCLUSION