The $Z_H \to \gamma H$ decay in the Littlest Higgs Model

TL;DR

This paper calculates the decay rate of the $Z_H$ boson into a photon and Higgs in the Littlest Higgs model, and assesses its detectability at the LHC considering background processes.

Contribution

It provides the first detailed one-loop calculation of the $Z_H o \gamma H$ decay in the Littlest Higgs model including recent experimental constraints.

Findings

Branching ratios around $10^{-5}$ for $f=2,3,4$ TeV.

Estimated event numbers at the LHC suggest detectability.

The signal exceeds the Standard Model background.

Abstract

We present the calculation of the $Z_H \to \gamma H$ decay in the context of the Littlest Higgs model at one-loop level. Our calculations include the contributions of fermions, scalars and gauge bosons in accordance with the most recent experimental constraints on the parameters space of the model. We find branching ratios of the order of $10^{-5}$ for the energy scale $f=2,3,4$ TeV on the $0.1<c<0.9$ region. In order to provide a complementary study we calculated the production cross section of the $Z_H$ boson in $pp$ collisions at Large Hadron Collider with a center of mass energy of 14 TeV. By using the integrated luminosity projected for the Large Hadron Collider in the last stage of operation, we estimated the number of events for this process. Moreover, we analyze the SM background for the Higgs-photon associated production and found that the $pp\to Z_H X \to \gamma H$ production is above the SM background.