气泡碰撞产生粒子
Particle production from bubble collisions
AI总结：
研究宇宙相变中超相对论性气泡碰撞产生粒子的问题，提出类似高能碰撞部分子描述的替代形式，通过壳上散射研究重标量等粒子产生及对暗物质等方面的影响。
AI中文摘要：
在宇宙相变过程中，超相对论性气泡的碰撞可以产生比相变尺度重得多的粒子。以往的分析将此过程建模为标量背景的离壳衰变。我们表明，其结果在参数上高估了硬粒子的产生，并且依赖于规范选择和场空间中的坐标选择。我们提出了一种替代形式，类似于高能碰撞的部分子描述。在超相对论极限下，碰撞的气泡几乎自由通过，硬粒子产生源于构成洛伦兹收缩壁的量子之间的壳上散射。我们将此方法应用于重标量、费米子和矢量粒子的产生，并研究其对暗物质、轻子生成、引力子产生和原初引力波的影响。
英文摘要：
Collisions of ultra-relativistic bubbles during cosmological phase transitions can produce particles much heavier than the transition scale. Previous analyses modelled this process as the off-shell decay of the scalar background. We show that its results parametrically overestimate hard particle production and depend on the gauge choice and the coordinate choice in field space. We propose an alternative formalism, analogous to the partonic description of high-energy collisions. In the ultra-relativistic limit, the colliding bubbles undergo nearly free passage and hard production arises from on-shell scatterings among the quanta constituting the Lorentz-contracted walls. We apply this approach to heavy scalar, fermion, and vector particle production, and study the implications for dark matter, leptogenesis, graviton production and primordial gravitational waves.
