Searching for scalar boson decaying into light $Z'$ boson at collider experiments in $U(1)_{L_\mu-L_\tau}$ model

TL;DR

This paper explores collider signatures of a scalar boson in a $U(1)_{L_m-tau}$ model, focusing on its decay into light $Z'$ bosons, with implications for muon magnetic moment anomalies and collider detection prospects.

Contribution

It introduces a collider search strategy for a scalar boson decaying into light $Z'$ bosons within the $U(1)_{L_m-tau}$ framework, connecting theoretical model features with experimental detection.

Findings

Constraints on gauge coupling and mixing parameters established.

Potential for discovery at LHC and ILC analyzed.

Significance estimates suggest feasible detection under certain conditions.

Abstract

We study a model with $U(1)_{L_\mu - L_\tau}$ gauge symmetry and discuss collider searches for a scalar boson, which breaks $U(1)_{L_\mu - L_\tau}$ symmetry spontaneously, decaying into light $Z'$ gauge boson. In this model, the new gauge boson, $Z'$, with a mass lighter than $\mathcal{O}(100)$ MeV, plays a role in explaining the anomalous magnetic moment of muon via one-loop contribution. For the gauge boson to have such a low mass, the scalar boson, $\phi$ with $\mathcal{O}(100)$ GeV mass appears associated with the symmetry breaking. We investigate experimental constraints on $U(1)_{L_\mu - L_\tau}$ gauge coupling, kinetic mixing, and mixing between the SM Higgs and $\phi$. Then collider search is discussed considering $\phi$ production followed by decay process $\phi \to Z' Z'$ at the large hadron collider and the international linear collider. We also estimate discovery significance at the linear collider taking into account relevant kinematical cut effects.