标题： 一级相变的 sphaleron 速率的非微扰测定 显示英文标题

标题： Non-perturbative determination of the sphaleron rate for first-order phase transitions

摘要： 在标准模型的许多扩展中，高温下的电弱相变可以用一个最小的维度约化有效理论来描述，该理论包含SU(2)规范场和基本Higgs标量。 在这个有效理论中，所有热力学信息都由两个无量纲比值$x \equiv \lambda_3/g^2_3$和$y\equiv m^2_3/g^4_3$所支配，其中$\lambda_3$、$m^2_3$和$g_3$分别是有效的热标量自相互作用耦合、热质量以及有效的规范耦合。 通过使用非微扰格点模拟来确定整个对应于希格斯相的 $(x,y)$-平面中的拓扑激发（sphaleron）转换率，并结合之前格点计算得到的泡泡成核结果，我们找到了一个条件 $x(T_c) \lesssim 0.025$，以保证重子不对称性的保留，这相当于对于（规范不变的）希格斯凝聚态的 $v/T_c \equiv \sqrt{2 \langle \phi^\dagger \phi \rangle}/T_c \gtrsim 1.33$。 这表明电弱重子生成机制的可行性要求相变比之前预期的稍微更强一些。 最后，我们提出了一种通用模板，用于分析大范围超出标准模型理论中的此类可行性问题，在这些理论中，新场足够重，可以在高温下被积分掉。 显示英文摘要

摘要： In many extensions of the Standard Model electroweak phase transitions at high temperatures can be described in a minimal dimensionally reduced effective theory with SU(2) gauge field and fundamental Higgs scalar. In this effective theory, all thermodynamic information is governed by two dimensionless ratios $x \equiv \lambda_3/g^2_3$ and $y\equiv m^2_3/g^4_3$, where $\lambda_3$, $m^2_3$ and $g_3$ are the effective thermal scalar self-interaction coupling, the thermal mass and the effective gauge-coupling, respectively. By using non-perturbative lattice simulations to determine the rate of sphaleron transitions in the entire $(x,y)$-plane corresponding to the Higgs phase, and by applying previous lattice results for the bubble nucleation, we find a condition $x(T_c) \lesssim 0.025$ to guarantee preservation of the baryon asymmetry, which translates to $v/T_c \equiv \sqrt{2 \langle \phi^\dagger \phi \rangle}/T_c \gtrsim 1.33$ for the (gauge-invariant) Higgs condensate. This indicates that viability of the electroweak baryogenesis requires the phase transition to be slightly stronger than previously anticipated. Finally, we present a general template for analysing such viability in a wide class of beyond the Standard Model theories, in which new fields are heavy enough to be integrated out at high temperature.