R-parity Violating Supersymmetric Explanation of the Anomalous Events at
  ANITA
  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.
