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Title: Constraining gravitino dark matter with the cosmic microwave background

Abstract

We consider supergravity models in which the lightest supersymmetric particle (LSP) is a stable gravitino. The next-to-lightest supersymmetric particle (NLSP) freezes out with its thermal relic density and then decays after (10{sup 5}-10{sup 10})sec, injecting high-energy photons into the cosmic plasma. These photons heat up the electron plasma which then thermalizes with the cosmic microwave background (CMB) via Compton scattering, bremsstrahlung and double-Compton scattering. Contrary to previous studies which assume instantaneous energy injection, we solve the full kinetic equation for the photon number density with a source term describing the decay of the NLSP. This source term is based on the requirement that the injected energy be almost instantaneously redistributed by Compton scattering, hence leading to a time-dependent chemical potential. We investigate the case of a stau NLSP and determine the constraints on the gravitino and stau masses from observations of the CMB spectrum by assuming that all gravitino LSPs come from stau NLSP decays. Unlike the analytical approximations, we find that there may be a stau mass below which the constraint from the CMB spectrum vanishes.

Authors:
 [1];  [2]
  1. Institut fuer Theoretische Physik, ETH Zuerich, Hoenggerberg, 8093 Zurich (Switzerland)
  2. Departement de Physique Theorique, Universite de Geneve, 24 quai Ernest Ansermet, 1211 Geneva 4 (Switzerland)
Publication Date:
OSTI Identifier:
20795699
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevD.73.023507; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BREMSSTRAHLUNG; COMPTON EFFECT; COSMIC RADIATION; DENSITY; ELECTRONS; KINETIC EQUATIONS; NONLUMINOUS MATTER; PARTICLE DECAY; PHOTONS; POTENTIALS; RADIOWAVE RADIATION; RELICT RADIATION; SPARTICLES; SUPERGRAVITY

Citation Formats

Lamon, Raphaeel, and Durrer, Ruth. Constraining gravitino dark matter with the cosmic microwave background. United States: N. p., 2006. Web. doi:10.1103/PHYSREVD.73.0.
Lamon, Raphaeel, & Durrer, Ruth. Constraining gravitino dark matter with the cosmic microwave background. United States. doi:10.1103/PHYSREVD.73.0.
Lamon, Raphaeel, and Durrer, Ruth. Sun . "Constraining gravitino dark matter with the cosmic microwave background". United States. doi:10.1103/PHYSREVD.73.0.
@article{osti_20795699,
title = {Constraining gravitino dark matter with the cosmic microwave background},
author = {Lamon, Raphaeel and Durrer, Ruth},
abstractNote = {We consider supergravity models in which the lightest supersymmetric particle (LSP) is a stable gravitino. The next-to-lightest supersymmetric particle (NLSP) freezes out with its thermal relic density and then decays after (10{sup 5}-10{sup 10})sec, injecting high-energy photons into the cosmic plasma. These photons heat up the electron plasma which then thermalizes with the cosmic microwave background (CMB) via Compton scattering, bremsstrahlung and double-Compton scattering. Contrary to previous studies which assume instantaneous energy injection, we solve the full kinetic equation for the photon number density with a source term describing the decay of the NLSP. This source term is based on the requirement that the injected energy be almost instantaneously redistributed by Compton scattering, hence leading to a time-dependent chemical potential. We investigate the case of a stau NLSP and determine the constraints on the gravitino and stau masses from observations of the CMB spectrum by assuming that all gravitino LSPs come from stau NLSP decays. Unlike the analytical approximations, we find that there may be a stau mass below which the constraint from the CMB spectrum vanishes.},
doi = {10.1103/PHYSREVD.73.0},
journal = {Physical Review. D, Particles Fields},
number = 2,
volume = 73,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
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