Charm associated production of the pseudoscalar Higgs boson $h''$ in the MCPM' at the LHC

TL;DR

This paper investigates the production of a pseudoscalar Higgs boson $h''$ in the MCPM' model at the LHC, focusing on charm-associated production, decay channels, and potential signals amidst backgrounds, with implications for experimental searches.

Contribution

It provides a detailed analysis of $h''$ production and decay in the MCPM' model, highlighting large cross sections and resonance signals in the $car c car c$ channel at the LHC, and discusses strategies to improve signal detection.

Findings

Cross section for $p p o h'' c ar c$ is comparable to Drell-Yan production.

Dominant decay of $h''$ is into $c ar c$ jets.

Promising resonance signals in the $c ar c c ar c$ channel.

Abstract

We discuss charm associated production of the pseudoscalar Higgs boson $h''$ in the MCPM'. In our analysis we assume $m_{h''}$ = 95.4 GeV, which corresponds to an enhancement observed by the CMS collaboration in the $\gamma \gamma$ channel. As discussed recently, the MCPM' is consistent with the CMS enhancement. In this model the $h''$ Higgs boson of this mass decays dominantly into $c \bar c$ jets. The cross section for the associated $h''$ production in $p p \to h'' c \bar c$ is found to be almost as big as that for the Drell-Yan (DY) $c \bar c \to h''$ production, much larger than that for two-gluon fusion $g g \to h''$. Since in the MCPM' the dominant $h''$ decay is into the $c \bar c$ channel we have to deal with the $p p \to c \bar c c \bar c$ process with $c$ and $\bar c$ jets. In addition to the signal processes, we have sizeable single parton scattering (SPS) and double parton scattering (DPS) nonresonant background. In our analysis we include diagrams of gluon-gluon fusion $g g \to h''$ which lead to the $c \bar c c \bar c$ final state. We discuss also the possible role of the reaction $p p \to h'' h''$. Assuming 100\% c and $\bar c$ jet tagging we discuss in detail how to improve the signal-to-background ratio. Our analysis shows promising resonance-like enhancements and relatively large cross sections in the $c \bar c c \bar c$ channel within the MCPM'. In an appendix we discuss the total cross section for $h''$ production at the LHC. We also compare distributions for the reactions $p p \to h'' X$ and $p p \to Z X$ with $h''$ and $Z$ decaying to $c\bar c$ and $\mu^{+}\mu^{-}$. We hope that the LHC collaborations will in the future perform the experimental studies corresponding to the theoretical studies discussed here.