h → γγ in U(1) R -lepton number model with a right-handed neutrino

Abstract

We perform a detailed study of the signal rate of the lightest Higgs boson in the diphoton channel (µ γγ ), recently analyzed by both the ATLAS and CMS collaborations at the Large Hadron Collider, in the framework of U(1) R − lepton number model with a right handed neutrino superfield. The corresponding neutrino Yukawa coupling, 'f ', plays a very important role in the phenomenology of this model. A large value of f ∼ O(1) provides an additional tree level contribution to the lightest Higgs boson mass along with a very light (mass ∼ a few hundred MeV) bino like neutralino and a small tree level mass of one of the active neutrinos that is compatible with various experimental results. In the presence of this light neutralino, the total decay width of the Higgs boson and its various branching fractions are affected. When studied in conjunction with the recent LHC results, these put significant constraints on the parameter space. The signal rate µ γγ obtained in this scenario is compatible with the recent results from both the ATLAS and the CMS collaborations at 1σ level. A small value of 'f ', on the other hand, is compatible with a sterile neutrino acting as a 7 keV dark matter that can explain the observation of a mono-energetic X-ray photon line by the XMM-Newton X-ray observatory. Because of the absence of a light neutralino, the total decay width of the lightest Higgs boson in this case remains close to the SM expectation. Hence, in the small 'f ' scenario we obtain a relatively larger value of µ γγ which is closer to the central values reported recently by these two collaborations.

Erratum to: h → γγ in U(1) R -lepton number model with a right-handed neutrino

“…This is also manifested in the upper right panel of figure 1 where the variations of k γγ with mt are almost independent of tan β. The relative sign in the Higgsneutralino-neutralino coupling also implies a significantly smaller value of g h χ 0 7 χ 0 8 when compared to figure 6 of reference [1] (shown in lower left panel of figure 1). This in turn means that the partial decay widths of the Higgs boson to these light neutralino states are small.…”

“…Earlier, in our code everywhere we used sin α = +S 42 , whereas the relation should be sin α = −S 42 as correctly mentioned just before equation (B.10) of our published paper [1].In addition, we missed out on a factor symmetric under i ↔ j in the expression for ζ ij in equation (B.8). This factor would also show up in the expressions for η ij and ξ ij in equation (B.11) in terms of which ζ ij was expressed in equation (B.10).…”

“…This is because hbb coupling (which controls the total decay width of the Higgs boson in a significant way) becomes independent of tan β for larger values of JHEP09 (2015) Figure 2. Modified versions of figures 9 and 10 of reference [1]. Note that contrary to reference [1], no constraint on the parameter space (more explicitly, on tan β) can be obtained from the invisible decay width of the Higgs boson.…”

“…This in turn means that the partial decay widths of the Higgs boson to these light neutralino states are small. Naturally, no constraint can be drawn from the total decay width of the Higgs boson (figure 7 of reference [1] does no longer hold) and a comparatively larger value of µ γγ can be expected. We also present the modified version of figure 8 of reference [1] in the lower right panel of figure 1.…”

“…Naturally, no constraint can be drawn from the total decay width of the Higgs boson (figure 7 of reference [1] does no longer hold) and a comparatively larger value of µ γγ can be expected. We also present the modified version of figure 8 of reference [1] in the lower right panel of figure 1. It is clear that the presence of a bino-like light neutralino state is not yet constrained from the invisible decay width of the Higgs boson in our scenario with all the curves staying well below the experimentally derived upper bound of ∼ 20% for the invisible branching fraction of the Higgs boson.…”