A Simultaneous Solution to Baryogenesis and Dark Matter Problems

TL;DR

The paper addresses the joint origin of the cosmological baryon asymmetry and cold dark matter by proposing a mechanism that introduces B-L carrying, electroweak-sphaleron-blind particles (R-particles). At a temperature $T^* > T_{EW}$, a $B-L$ asymmetry is created between the SM sector and the R-sector, while CP-violating decays generate the necessary asymmetry, and standard electroweak sphalerons reprocess the SM $B-L$ into the observed BAU; the R-sector retains the opposite asymmetry and provides the CDM relic. In supersymmetric realizations (MSSM), R-particles can be sleptons or other superpartners, with predicted mass scales such as light right-handed sneutrinos around $m \sim 2$ GeV or charged sleptons with $m_{\tilde{l}} \lesssim 1$ TeV, including scenarios with long-lived sparticles and exotic bound states like superhydrogen. If right-handed neutrinos are included, CDM can be entirely composed of ${\tilde{\nu}}_R$ with $m_{\tilde{\nu}_R} \approx 1.8$ GeV, while satisfying collider and precision constraints; overall, the framework yields distinctive experimental signatures and motivates novel searches for non-traditional CDM signals and relic bound states.

Abstract

A new concept of generation of the cosmological baryon excess along with the cold dark matter (CDM) in the Universe is proposed and corresponding scenarios are outlined. Possible realizations of the idea in the framework of supersymmetric models are considered and constraints (predictions) on masses of sparticles compatible with the viability of the scenario are derived. Mulitiple predictions might be extracted from the concept. In particular, we predict a quite natural existence of a charge asymmetric component of CDM. A $\sim 10^{-2}$ part of CDM might exist in the form of electrically charged relic particles with masses $m \simeq 1$ TeV. They are negatively charged and are dresses by protons. This conjecture provides a rich field of immediate search for these particles. The charge symmetric component of CDM might be represented by very light, $m \approx 2$ GeV, very weakly interacting particles like right-handed sneutrinos ( so recoils expected are rare and have quite small energies, $E_{recoil} \sim 1$ KeV.) This leads by the way to prediction of long-living (charged) sparticles. Some new experimental proposals for non-traditional search of cold dark matter particles are mentioned.