Prospects of gravitational waves in the minimal left-right symmetric model

TL;DR

This paper investigates the potential for gravitational wave signals arising from phase transitions in the minimal left-right symmetric model, highlighting regions with detectable signals and their relation to model parameters.

Contribution

It provides a comprehensive analysis of gravitational wave prospects in the minimal LRSM, considering all constraints and identifying parameter regions with observable signals.

Findings

Detectable gravitational waves can originate from the phase transition in the LRSM.

GWs are predicted at frequencies between 0.1 and 10 Hz, detectable by BBO and DECIGO.

Light $SU(2)_R$-breaking scalars and other heavy particles influence GW production.

Abstract

The left-right symmetric model (LRSM) is a well-motivated framework to restore parity and implement seesaw mechanisms for the tiny neutrino masses at or above the TeV-scale, and has a very rich phenomenology at both the high-energy and high-precision frontiers. In this paper we examine the phase transition and resultant gravitational waves (GWs) in the minimal version of LRSM. Taking into account all the theoretical and experimental constraints on LRSM, we identify the parameter regions with strong first-order phase transition and detectable GWs in the future experiments. It turns out in a sizeable region of the parameter space, GWs can be generated in the phase transition with the strength of $10^{-17}$ to $10^{-12}$ at the frequency of 0.1 to 10 Hz, which can be detected by BBO and DECIGO. Furthermore, GWs in the LRSM favor a relatively light $SU(2)_R$-breaking scalar $H_3^0$, which is largely complementary to the direct searches of a long-lived neutral scalar at the high-energy colliders. It is found that the other heavy scalars and the right-handed neutrinos in the LRSM also play an important part for GW signal production in the phase transition.