Role of cosmological gravitational particle production in baryogenesis

We investigate the generation of the baryon asymmetry within the framework of cosmological gravitational particle production, employing the Bogoliubov approach. We examine two well-known baryogenesis scenarios, namely baryogenesis in grand unified theories (GUT) and leptogenesis, while considering reheating temperatures sufficiently low for thermal processes to be negligible. Considering <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>α</a:mi></a:mrow></a:math>–attractor T-models for the inflaton potential, we demonstrate that GUT baryogenesis from scalar decays can be successful across a large range of conformal couplings with gravity, without necessitating substantial levels of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>C</c:mi><c:mi>P</c:mi></c:math> violation. In the case of leptogenesis, we find that the reheating temperature should be <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:msub><e:mi>T</e:mi><e:mrow><e:mi>RH</e:mi></e:mrow></e:msub><e:mo>≲</e:mo><e:msup><e:mn>10</e:mn><e:mn>6</e:mn></e:msup><e:mtext> </e:mtext><e:mtext> </e:mtext><e:mi>GeV</e:mi></e:math> for right-handed neutrino masses <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:msub><g:mi>M</g:mi><g:mn>1</g:mn></g:msub><g:mo>≲</g:mo><g:mn>6</g:mn><g:mo>×</g:mo><g:msup><g:mn>10</g:mn><g:mn>12</g:mn></g:msup><g:mtext> </g:mtext><g:mtext> </g:mtext><g:mi>GeV</g:mi></g:math> to generate the observed asymmetry. Published by the American Physical Society 2024