Supernova constraints on a superlight gravitino
- Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States)
- Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)
- Department of Physics, Southern Methodist University, Dallas, Texas 75275 (United States)
In supergravity models with low supersymmetry-breaking scale, the gravitinos can be superlight, with mass in the 10{sup {minus}6}eV to a few keV range. In such a case, gravitino emission provides a new cooling mechanism for protoneutron stars and therefore can provide constraints on the mass of a superlight gravitino. This happens because the coupling to matter of superlight gravitinos is dominated by its Goldstino component, whose coupling to matter is inversely proportional to the scale of supersymmetry breaking and increases as the gravitino mass decreases. Present observations therefore provide lower limits on the gravitino mass. Using the recently revised Goldstino couplings, we find that the two dominant processes in supernova cooling are e{sup +}e{sup {minus}}{r_arrow}{tilde G}{tilde G} and {gamma}+e{sup {minus}}{r_arrow}e{sup {minus}}{tilde G}{tilde G}. They lead to a lower limit on the supersymmetry-breaking scale {Lambda}{sub S} from 160 to 500 GeV for core temperatures 30 to 60 MeV and electron chemical potentials 200 to 300 MeV. The corresponding lower limits on the gravitino mass are 0.6 to 6{times}10{sup {minus}6}eV. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 573866
- Journal Information:
- Physical Review, D, Vol. 57, Issue 1; Other Information: PBD: Jan 1998
- Country of Publication:
- United States
- Language:
- English
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