Bounds on charged, stable superpartners from cosmic ray production

Abstract

Supersymmetric models often predict a lightest superpartner (LSP) which is electrically charged and stable on the timescales of collider experiments. If such a particle were to be observed experimentally, is it possible to determine whether or not it is stable on cosmological timescales? Charged, stable particles are usually considered to be excluded by cosmological arguments coupled with terrestrial searches for anomalously heavy water molecules. But when the cosmology is significantly altered, as can happen in models with large extra dimensions, these arguments are in turn significantly weakened. In this paper we suggest an alternate way to use searches for superheavy water to constrain the lifetimes of long-lived, charged particles, independent of most cosmological assumptions. By considering SUSY production by cosmic rays in the upper atmosphere, we are able to use current bounds on superheavy water to constrain the mass scale of squarks and gluinos to be greater than about 230 GeV, assuming a stable, charged LSP. This bound can be increased, but only by significantly increasing the size of the initial water sample tested.

A Simple Model of Gauged Lepton and Baryon Charges

“…However, in our case the X scalar can lie in the electroweak scale. This is in agreement with a search (Byrne et al, 2002) for the lower mass bound of the squarks and gluinos about 230 GeV. It is also in agreement with searches (Smith et al, 1982;Yamagata et al, 1993).…”

Search for charged massive long-lived particles ats=1.96 TeV

“…Although cosmological observations place severe limits on stable massive particles [1,12], these limits do not rule out the particles predicted by models studied here. We are sensitive to CMLLPs with lifetimes longer than 25 ns, with best sensitivity for lifetimes longer than 1 µs.…”

“…Several extensions of the standard model (SM) including some SUSY models predict the existence of massive long-lived particles (MLLP) [1]. Their existence could explain the origin of dark matter.…”

Modified Higgs boson phenomenology from gauge or gaugino mediation in the next-to-minimal supersymmetric standard model

“…If stable on the lifetime of the universe, heavy charged exotics are very stringently constrained by searches for anomalously heavy atoms. These bounds are so severe that even the tiny density of heavy exotics created by cosmic rays is unacceptably large [58]. Long-lived heavy exotics are also dangerous if they decay after nucleosynthesis as their decay products can modify the light element abundances, distort the CMB blackbody spectrum, or contribute to cosmic rays [59].…”