Cosmological Problems in Supersymmetry Theories

我们研究了物质-反物质不对称（重子生成）的起源，以及在超对称框架下早期宇宙中不稳定粒子的宇宙学效应。理论。考虑到有限的温度效应，我们研究了阿弗莱克-丁（Affleck-Dine， AD）机制作为一个有前途的重子发生过程。负热校正使AD场长期被困在远离原点的地方，直到宇宙的温度足够低。在某些情况下，在AD机制中产生的q球的非线性动力学对重子的不对称性有重要的抑制作用。然而，我们发现，在q球形成动力学不影响重子不对称性的参数空间中，仍有可能产生适量的重子不对称性。我们还发现，在实标量场理论中，如果标量势满足一定条件，则存在类孤子解“i球”。我们研究了长寿命不稳定粒子如引力子和模子的大爆炸核合成（BBN）。如果不稳定粒子的寿命超过0.1秒，它的衰变可能会在爆炸期间或之后引起非热核反应，从而改变对标准爆炸情景的预测。我们特别注意了它的强子衰变模式，并计算了轻元素的原始丰度。利用这一结果，我们推导出了不稳定粒子原始丰度的约束条件。将所得结果应用于引力子问题，得到了膨胀后再加热温度的上界。我们研究了mev尺度的再加热场景，其中中微子的热化可能不足。我们特别注意了振荡对中微子热化过程的影响，并得到了再加热温度的严格约束（~ 2MeV）。

We studied the origin of matter-anti-matter asymmetry (baryogenesis), and the cosmological effects of unstable particles in the early universe in the frame of supersymmetry. theories.We investigated the Affleck-Dine (AD) mechanism as promising baryogenesis process taking account of finite temperature effect. The AD field is trapped far away from the origin by the negative thermal correction for a long time until the temperature of the universe becomes low enough. In some case, non-linear dynamics of Q-balls produced in the AD mechanism suppresses the baryon asymmetry crucially. However, it was found that there remains some parameter space for which the dynamics of Q-ball formation does not affect the baryon asymmetry and it is possible to generate the right amount of the baryon asymmetry. We also found that there exists a soliton-like solution called "I-ball" in theories of a real scalar field if the scalar potential satisfies some conditions.We studied the big-bang nucleosynthesis (BBN) with the long-lived unstable particle such as gravitino and moduli. If the lifetime of the unstable particle is longer than about 0.1 sec, its decay may cause non-thermal nuclear reactions during or after the BBN, altering the predictions of the standard BBN scenario. We paid particular attention to its hadronic decay modes and calculate the primordial abundances of the light elements. Using the result, we derived constraints on the primordial abundance of the unstable particle. We applied our results to the gravitino problem, and obtained upper bound on the reheating temperature after inflation.We investigated the MeV-scale reheating scenario wherein the thermalization of neutrinos could be insufficient. We paid particular attention to the oscillation effects on the thermalization processes of neutrinos and obtained the stringent constraint on the reheating temperature (〜2MeV).