标题： 复杂标量旁观场对自发重子不对称性的影响 显示英文标题

标题： Impact of a complex scalar spectator field on baryon asymmetry within spontaneous baryogenesis

摘要： 我们通过研究当暴胀子$\theta$与复数观测标量场$\phi$最小耦合时重子不对称性的产生，扩展了自发重子生成的框架，如$\theta^2|\phi|^2$所示。 为了做到这一点，我们还考虑$\phi$通过类似 Yukawa 的相互作用与曲率标量$R$非最小耦合。 我们不考虑观测场与标准模型费米子的进一步相互作用，将其视为暗标量场\emph{事实上的}。 在评估再加热时期重子数守恒的破坏时，在一个完全均匀和各向同性的宇宙中，我们采用半经典方法，其中$\theta$、$\phi$和引力被视为经典场，而费米子则被量子化。 我们分别在微扰理论的一阶和零阶下求解标量场和观测场的运动方程，首先忽略宇宙的膨胀。 随后，我们量化观测场如何改变暴胀动力学，并通过计算相应的衰变振幅来找到通过标量场衰变为费米子-反费米子对所产生的重子不对称性。 因此，我们得到标准自发重子生成的小一阶修正，并最终讨论费米子之间的质量混合。 相应地，考虑宇宙膨胀的影响被纳入，展示了当$\phi$与$R$之间的耦合在何时明显改变整体重子不对称性。 显示英文摘要

摘要： We extend the framework of spontaneous baryogenesis by investigating the generation of baryon asymmetry when the inflaton, $\theta$, is minimally coupled with a complex spectator scalar field $\phi$, as $\theta^2|\phi|^2$. To do so, we also consider $\phi$ non-minimally coupled with the Ricci scalar curvature $R$ through a Yukawa-like interaction. We do not consider further interactions of the spectator field with the fermions of the Standard Model, considering it \emph{de facto} as a dark scalar field. In evaluating the violation of the baryon-number conservation during the reheating epoch, in a perfectly homogeneous and isotropic universe, we follow a semiclassical approach, where $\theta$, $\phi$ and gravity are considered as classical fields, whereas the fermions are quantized. We solve the equations of motion for the inflaton and spectator fields, respectively at first and zero-order in perturbation theory, neglecting at first stage the expansion of the universe. Afterwards, we quantify how the spectator field modifies the inflationary dynamics and thus find the baryon asymmetry produced via the inflaton decays into fermion-antifermion pairs by computing the corresponding decay amplitudes. We therefore obtain small first order correction to standard spontaneous baryogenesis and finally discuss the mass-mixing between fermions. Accordingly, the effects of considering the universe expansion are accounted, showing when the coupling between $\phi$ and $R$ becomes noticeable in altering the overall baryon asymmetry.