Sleptogenesis

Abstract

We propose that the observed baryon asymmetry of the Universe can naturally arise from a net asymmetry generated in the sleptonic sector at fairly low reheat temperatures. The best candidate is indeed the right-handed sneutrino. The initial asymmetry in the sneutrino sector can be produced from the decay of the inflaton, and is subsequently transferred into the Standard Model (s)lepton doublet via the decay of the sneutrino. The active sphalerons then reprocess the leptonic asymmetry into the baryonic asymmetry. The marked feature of this scenario is that the lepton asymmetry is decoupled from the neutrino Yukawa sector. We exhibit that our scenario can be embedded within models which seek the origin of a tiny mass for neutrinos.Comment: 7 revtex pages, 2 figures (uses axodraw). Minor changes for better clarification and updated references. Final version to appear in Phys. Rev.

Punctuated inflation and the low CMB multipoles

“…Such potentials are known to arise in certain minimal supersymmetric extensions of the standard model [48], and their role as an inflaton and its related effects have been studied recently [49,50,51]. (We should also hasten to add that the specific case of n = 3 has been considered much earlier for reasons similar to ours, viz.…”

“…In the MSSM case, inflation occurs when the field values are much smaller than the Planck scale [49,50,51]. However, in our case, since we demand two epochs of slow roll, it necessarily requires that the initial values of the field (assuming, say, about 60 e-folds of inflation) be greater than M Pl .…”

“…We had mentioned earlier that potentials of the type (1) are encountered in the Minimal Supersymmetric Standard Model (MSSM) [48], and that their role as an inflaton has been analyzed recently [49,50,51]. At this point it is important that we highlight the differences between MSSM inflation and the scenario we are considering.…”

“…We find that the form of the potentials motivated by a class of certain minimal supersymmetric extensions of the standard model provide us with the desired behavior [48,49,50,51]. These large field models allow a period of fast roll sandwiched between two stages of slow roll inflation ‡.…”

Stringy effects during inflation and reheating

“…First, we should take the preceding discussion of the modulus (and SM throat) evolution with a grain of salt. After all, it would not be surprising if there are 10D or string corrections, and we do not have a complete picture of the stationary ge- 16 A full thermalization in the field theory case need not be completed during reheating [142], especially in the case of supersymmetric theories, because 2 $ 2 and 2 ! 3 processes, required for thermalization [143], are mediated via gauge bosons/gauginos and Higgses.…”