Color and charge breaking minima in the MSSM

The scalar potential of theories with broken supersymmetry can have a number of local minima characterized by different gauge groups. Symmetry properties of the physical vacuum constrain the parameters of the MSSM. We discuss these constraints, in particular those that result from the vacuum stability with respect to quantum tunneling.Comment: 3 pages, latex, macros and three figures included, complete postscript file is available at ftp://dept.physics.upenn.edu/pub/Kusenko/SUSY96.ps . Talk presented at SUSY'96, University of Maryland, May 29 - June 1, 199

Bound states and resonances in the scalar sector of the MSSM

The trilinear couplings of squarks and sleptons to the Higgs bosons can give rise to a spectrum of bound states with exotic quantum numbers, for example, those of a leptoquark.Comment: 8 pages, 2 eps figures, latex, epsf; published version (minor changes in wording and referencing

Small Q balls

We develop an adequate description of non-topological solitons with a small charge, for which the thin-wall approximation is not valid. There is no classical lower limit on the charge of a stable Q-ball. We examine the parameters of these small-charge solitons and discuss the limits of applicability of the semiclassical approximation.Comment: 10 pages, latex, epsf, 2 figures include

Supersymmetric Q-balls: theory and cosmology

MSSM predicts the existence of Q-balls, some of which can be entirely stable. Both stable and unstable Q-balls can play an important role in cosmology. In particular, Affleck-Dine baryogenesis can result in a copious production of stable baryonic Q-balls, which can presently exist as a form of dark matter.Comment: talk presented at PASCOS-98; transparencies available at http://wwwinfo.cern.ch/~kusenko/PASCOS98.ps; 4 pages, latex, sprocl, psfi

Resonant production of gamma rays in jolted cold neutron stars

Acoustic shock waves passing through colliding cold neutron stars can cause repetitive superconducting phase transitions in which the proton condensate relaxes to its equilibrium value via coherent oscillations. As a result, a resonant non-thermal production of gamma rays in the MeV energy range with power up to 10^(52) erg/s can take place during the short period of time before the nuclear matter is heated by the shock waves.Comment: 9 pages, 2 figures include

Ultrahigh-energy nuclei, photons, and magnetic fields

Combined recent data from cosmic-ray detectors and gamma-ray detectors have produced some surprising insights regarding the sources of ultrahigh-energy cosmic rays (UHECRs), magnetic fields inside and outside the Milky Way, and the universal photon backgrounds. The energy-dependent composition of UHECRs implies a non-negligible contribution of sources located in the Milky Way, such as past gamma-ray bursts that took place in our Galaxy. Extended halos of distant sources seen in the Fermi data imply that intergalactic magnetic fields have average strengths of the order of a femtogauss. Such relatively low magnetic fields imply that the protons from distant blazars generate a detectable flux of secondary gamma rays in their interactions with the photon background. A comparison with the data shows an excellent agreement of the secondary photons with the spectra of distant blazars observed by atmospheric Cherenkov telescopes.Comment: 6 pages, 3 figures, talk presented at "Cosmic Ray International Seminar (CRIS 2010)", Catania, September, 13-17, 201