Revisiting metastable cosmic string breaking

• DOI: 10.1007/jhep04(2024)068
• Publication Date: 2024-04-13T02:01:25Z
• Authors: Akifumi Chitose; Masahiro Ibe; Yuhei Nakayama; Satoshi Shirai; Keiichi Watanabe
• Keywords: Cosmic string; Metastability

A bstract Metastable cosmic strings appear in models of new physics with a two-step symmetry breaking G → H 1, where π 1 ( ) ≠ 0 and = 0. They decay via the monopole-antimonopole pair creation inside. Conventionally, rate has been estimated by an infinitely thin string approximation, which requires large hierarchy between scales. In this paper, we reexamine it taking into account finite sizes both monopole. We obtain robust lower limit on tunneling factor $$ {e}^{-{S}_B} <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>e</mml:mi> <mml:mrow> <mml:mo>−</mml:mo> <mml:msub> <mml:mi>S</mml:mi> <mml:mi>B</mml:mi> </mml:msub> </mml:mrow> </mml:msup> </mml:math> even for regimes conventional estimate is unreliable. particular, relevant to interpretation gravitational wave signals recently reported pulsar timing array experiments.