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.
Highlights
Left-right symmetric modelThe basic idea of left-right symmetric model (LRSM) is to extend the EW sector of SU(2)L × U(1)Y of the SM gauge group to be left-right symmetric, i.e. SU(2)L × SU(2)R × U(1)B−L
Special interests, as they might accommodate baryogenesis and explain the matterantimatter asymmetry observed in the universe [6,7,8,9]
Among various new physics candidates, except interpreting the EW symmetry breaking by the Higgs mechanism, the minimal left-right symmetric model (LRSM) [100,101,102] offers an elegant solution to some key fundamental questions in or beyond the SM, such as parity violation/restoration, CP violation, and generation of tiny neutrino masses at the TeV-scale, which are among the focuses of experimental searches of new physics at the highenergy colliders and high-precision experiments
Summary
The basic idea of LRSMs is to extend the EW sector of SU(2)L × U(1)Y of the SM gauge group to be left-right symmetric, i.e. SU(2)L × SU(2)R × U(1)B−L. When the right-handed triplet ∆R acquires a vacuum expectation value (VEV) vR, the gauge symmetry SU(2)L × SU(2)R × U(1)B−L in the LRSM is broken to the SM gauge group SU(2)L × U(1)Y. The SU(2)R × U(1)B−L symmetry can be broken only by a right-handed doublet HR [119, 120]. In this case, heavy vector-like fermions have to be introduced to generate the SM quark and lepton masses via seesaw mechanism (see [121]). There are three key energy scales in the LRSM, i.e. the right-handed scale vR, the EW scale vEW and the scale vL which is relevant to tiny active neutrino masses via type-II seesaw. We assume that the gauge coupling gR for SU(2)R can be different from the gauge coupling gL for SU(2)L, which might originate from renormalization group running effects such as in the D-parity breaking LRSM versions [159]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
