标题： 低尺度宇宙弦产生的引力波而不具备比例性 显示英文标题

标题： Gravitational waves from low-scale cosmic strings without scaling

摘要： 宇宙弦在标准模型的许多扩展理论中被预测存在，并且构成早期宇宙引力波（GWs）的一个合理来源。 在之前的一篇文章[1]中，我们指出，在标度场景中的弦环群体产生的引力波谱可以表现出与弦环基本振荡模式相关的尖锐截止频率。 在本文中，我们研究了由于节点-节点碰撞和尖点导致的粒子衰变对非标度场景下引力波谱的影响，该非标度场景在文献[2]中有介绍。 我们找到了基本谱中存在截止频率的解析条件，并给出了该频率的表达式。 在参数空间的大范围内，我们在非标度模型中的结果最终与标度模型中的结果相同。 最后，我们展示了当从有截止频率的区域过渡到没有截止频率的区域时，谱线如何变化。 通过将我们的解析估计与数值谱线在不同基准点上进行比较，验证了我们的解析估计。 显示英文摘要

摘要： Cosmic strings are predicted in many extensions of the Standard Model and constitute a plausible source of gravitational waves (GWs) from the early Universe. In a previous article [1], we pointed out that the GW spectrum from a population of string loops in the scaling regime can exhibit a sharp cutoff frequency associated with the fundamental oscillation mode of string loops. In this paper, we study the effect of particle decay due to kink-kink collisions and cusps on the GW spectrum in the nonscaling scenario introduced in Ref. [2]. We find analytical conditions for the existence of a cutoff frequency in the fundamental spectrum and provide expressions for this frequency. In large regions of parameter space, our results in the nonscaling model turn out to be identical to those in the scaling model. Finally, we demonstrate how the spectrum changes when transitioning from the regime with a cutoff frequency to the regime without a cutoff frequency. Our analytical estimates are validated at qualitatively different benchmark points by comparing them with numerical spectra.