Gravitino decay in high scale supersymmetry with R -parity violation

Abstract

We consider the effects of R-parity violation due to the inclusion of a bilinear μ 0 LH u superpotential term in high-scale supersymmetric models with an EeV scale gravitino as dark matter. Although the typical phenomenological limits on this coupling (e.g., due to lepton number violation and the preservation of the baryon asymmetry) are relaxed when the supersymmetric mass spectrum is assumed to be heavy (in excess of the inflationary scale of 3 × 10 13 GeV), the requirement that the gravitino be sufficiently long lived so as to account for the observed dark matter density, leads to a relatively strong bound on μ 0 ≲ 20 GeV. The dominant decay channels for the longitudinal component of the gravitino are Zν, W AE l ∓ , and hν. To avoid an excess neutrino signal in IceCube, our limit on μ 0 is then strengthened to μ 0 ≲ 50 keV. When the bound is saturated, we find that there is a potentially detectable flux of monochromatic neutrinos with EeV energies.

Can the ANITA anomalous events be due to new physics?

“…These fall into three broad categories: (1) SM neutrinos of astrophysical origin could convert to beyond-the-standard-model (BSM) particles through interactions in the Earth, followed by propagation of the BSM particle until it reconverts to SM particles that initiate the observed hadronic air shower [6][7][8][9]; (2) dark matter (DM) that has accumulated within the Earth and decays to BSM particles that reconvert to SM particles shortly below the Antarctic surface could induce the air showers; or (3) an exotic flux of BSM particles, such as sterile neutrinos [10,11] incident upon the Earth interact to produce the observed particles near the Earth's surface. A possible source of such flux is the decay of long-lived DM particles [12][13][14].…”

Prospects for discovering supersymmetric long-lived particles with MoEDAL

“…On the other hand, explanations involving BSM physics have also been proposed [31,32], including heavy dark matter models [87] and SUSY [27][28][29][30]. Supersymmetry constitutes, in our opinion, one of the best proposed explanations of these events to date.…”

“…As an interesting byproduct of our analysis, we also present a brief discussion on the anomalous air shower events observed by the ANITA Collaboration [23,24], putting emphasis on the fact that the range of HSCP parameters probed by MoEDAL can be in the interesting regime of providing explanations for those events based on supersymmetric models [25][26][27][28][29][30][31][32][33]. Astrophysical explanations of these events are in tension with IceCube data [34,35], strengthening the possibility for an origin from physics Beyond the SM (BSM).…”

Connecting ANITA anomalous events to a nonthermal dark matter scenario

“…Therefore, several beyond standard model (BSM) proposals have been put forward to explain the observed events. They include sterile neutrino mixing [3,4], heavy dark matter (DM) [5][6][7][8][9][10], inelastic boosted DM [11], long lived charged particles like stau [12,13], R-parity violating supersymmetry (SUSY) [14], SUSY sphalerons configurations [15], leptoquarks [16], and radio pulses from axion-photon conversion [17]. Additionally, in Ref.…”