Thermal Inflation with Flaton Chemical Potential
Thermal inflation driven by a scalar field called a “flaton” is a possible scenario to solve the cosmological moduli problem. We study a model of thermal inflation with a flaton chemical potential. In the presence of the chemical potential, a negative mass squared of the flaton—which is necessary to terminate thermal inflation—is naturally induced. We identify the allowed parameter region for the chemical potential (μ) and the flaton self-coupling constant to solve the cosmological moduli problem and satisfy theoretical consistencies. In general, the chemical potential is a free parameter and it can be taken to be much larger than the typical scale of soft supersymmetry-breaking parameters of O(1) TeV. For μ ≳ 10⁸ GeV, we find that the reheating temperature after thermal inflation can be high enough for the thermal leptogenesis scenario to be operative. This is in sharp contrast to the standard thermal inflation scenario, in which the reheating temperature is quite low and a special mechanism is necessary for generating a sufficient amount of baryon asymmetry in the Universe after thermal inflation.