String Theory backgrounds with Torsion in the presence of Fermions and implications for Leptogenesis

4th Symposium on Prospects in the Physics of Discrete Symmetries

Sarkar, Sarben^1

Department of Physics, King's College London, Strand, London

WC2R 2LS, United Kingdom^1

关键词: Background solutions;    Bianchi identities;    Conformal invariance;    Fixed points;    Leptogenesis;    New mechanisms;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/631/1/012089/pdf
DOI  :  10.1088/1742-6596/631/1/012089

来源: IOP

【 摘 要 】

Fermions couple in a universal way to the the Kalb-Ramond field which occurs in the gravitational multiplet of string theory. The Kalb-Ramond field is a source of torsion and can provide a background for fermion dynamics. Solutions for this background in terms of the string effective action are discussed and are fixed "points" of conformal invariance conditions. Non- perturbative fixed points for the torsion in the absence of matter are shown to be compatible with perturbative fixed points in the presence of matter. Fermion coupling to such backgrounds can lead to both CP and CPT violation. Hence torsion can give a new mechanism for leptogenesis. The presence of anomalies in the Bianchi identity for the torsion, in the presence of matter, is crucial in giving a background solution for the torsion and dilaton with an acceptable cosmology.