Antideuteron limits on decaying dark matter with a tuned formation model

Abstract

We investigate the production of antideuterons from decaying dark matter, using gravitinos in supersymmetric models with trilinear R-parity violating (RPV) operators as an example. The model used for antideuteron formation is shown to induce large uncertainties in the predicted flux, comparable to uncertainties from cosmic-ray propagation models. We improve on the formation model by tuning hadronization and coalescence parameters in Monte Carlo simulations to better reproduce the hadron spectra relevant for antideuteron production. In light of current bounds on fluxes and future prospects from the AMS-02 and GAPS experiments we set limits on RPV couplings as a function of the gravitino mass.

Alternative formation model for antideuterons from dark matter

“…As has been show in Refs [4,5], tuning p 0 against experiments measuring different collision processes at differing energy scales does not give a consistent best fit value. Moreover, the coalescence model is sensitive to two-particle correlations for (anti)baryons, arising from the structure of the hadronization models in the Monte Carlo event generators used [9].…”

“…While modified slightly over the years, the coalescence model is still state-of-the-art. In calibrating p 0 on (relatively) modern experimental data, it has been found that while all available datasets can individually be consistently described by some value of p 0 , there is no consistent p 0 between datasets [4,5]. This has been explained by differences in the event generators used to simulate the data, and by the different physical properties of the processes measured, e.g.…”

“…As discussed in Ref. [4], hadronization parameters in Monte Carlos are usually not tuned to measured two-particle correlations, where they exist, nor indeed with any specific emphasis on reproducing (anti)nucleon spectra. Tuning hadronization parameters specifically towards antideuteron production is therefore a prospective way of achieving better consistency in fits to experimental data, as well as better agreement between different Monte Carlos.…”

Anti-helium from dark matter annihilations

“…Naively, one would expect this parameter to be the same despite the initial state of the process, since the coalescence momentum is related to the probability for thē pn pair to merge into an anti-deuteron. Unfortunately, as stressed in [45], the details of the hadronization process implemented through the Monte Carlo event generator can play a role and affect the phase space correlations between particles in the final state in different ways and thus a specific value of the coalescence momentum which can be good for a Edσ/dp [mbGeV [43,44] as a function of the coalescence momentum; in the right panel, the anti-deuteron production cross section for the best fit configuration is shown together with data points from [43] (in blue) and from [44] (in red).…”

Present Status and Future Plans of GAPS Antiproton and Antideuteron Measurement for Indirect Dark Matter Search

“…1, the predicted antideuteron spectrum from the lightest supersymmetric particle (LSP) neutralino [5], right-handed Kaluza-Klein neutrino of warped 5-dimensional grand unified theories (LZP) [6], and decaying LSP gravitino [7] are shown. Among these models, the gravitino DM cannot be seen by direct DM search experiments but can be detected only by cosmic-ray antideuterons [7]. The antideuteron search is also sensitive to some DM models with TeV-scale mass [8,9].…”