Abstract
In a temperature dependent CPT-Violating (CPTV) axial time-like background (induced by the Kalb-Ramond tensor field of string theory) we discuss leptogenesis by solving the Boltzmann equation.The current work non-trivially modifies the framework of a previous phenomenological approach by the authors where the CPTV axial background was considered to be a constant (with no microscopic justification). The constant background approximation though is shown to capture the main phenomenological features of leptogenesis. On comparing our analysis to the related chiral magnetic effect for axial current condensates, we conclude that the Kalb-Ramond field does not play the role of the chiral chemical potential needed for that effect.
Highlights
It has been shown [1,2,3] that matter-antimatter asymmetry, can occur in appropriate constant backgrounds in the cosmological (Robertson-Walker) frame of the early universe
Compared to the case of constant B0 studied in [3], we observe that the Lorentz violating (LV) and CPTV value of the background field B0 at decoupling TD = O(100) TeV, which yields phenomenologically acceptable lepton asymmetry in the universe is smaller, is in the keV range
In the presence of a chemical potential, the equilibrium populations of quarks and antiquarks are already different within thermal equilibrium, since the phase-space distribution functions between particles and antiparticles are different
Summary
It has been shown [1,2,3] that matter-antimatter asymmetry (through leptogenesis), can occur in appropriate constant backgrounds in the cosmological (Robertson-Walker) frame of the early universe. Such constant backgrounds were associated with postulated axial current condensates. In the model leptogenesis originates from tree-level decays of a heavy sterile (right-handed, Majorana) neutrino (RHN) into Standard Model (SM) leptons, in the presence of a generic CPTV timelike axial background [2,3]. In [3], a detailed study of the associated Boltzmann equations for the processes in (4), and their reciprocals, led to the result:
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