Pair production of color-octet scalars at the LHC

Ahmad Idilbi,Thomas Mehen,Chul Kim

doi:10.1103/physrevd.82.075017

Abstract

Heavy colored scalar particles, which exist in many models of new physics, can be pair produced at the LHC via gluon-gluon fusion and possibly form quarkoniumlike bound states. If the scalars are also charged under the electroweak gauge group, these bound states can then decay into electroweak bosons. This yields a resonant cross section for final states such as $\ensuremath{\gamma}\ensuremath{\gamma}$ that can exceed standard model backgrounds. This paper studies this process in the Manohar-Wise model of color-octet scalars (COS). Important threshold logarithms and final state Coulomb-like QCD interactions are resummed using effective field theory. We compute the resummed cross section for gluon-gluon fusion to COS pairs at the LHC as well as the resonant cross section for octetonium decaying to $\ensuremath{\gamma}\ensuremath{\gamma}$. The latter cross section exceeds the standard model diphoton cross section when the COS mass is less than 500 (350) GeV for $\sqrt{s}=14(7)\text{ }\text{ }\mathrm{TeV}$. Nonobservation of resonances below these energies can significantly improve existing bounds on COS masses.

Highlights

One of the main goals of the Large Hadron Collider (LHC) is to search for new physics (NP) around or above the 1 TeV scale
One possibility for new physics that may be discovered at the LHC is the existence of heavy color-octet scalars (COS)
In this work we have extended our previous analysis of single COS production [22] and considered the production cross section of two COS which bind together through Coulomb interactions to form a bound state called octetonium [16]

Summary

INTRODUCTION

One of the main goals of the Large Hadron Collider (LHC) is to search for new physics (NP) around or above the 1 TeV scale. We are interested in calculating the cross section in the threshold region, s ∼ (2mS), where sthe momentum squared of incoming partons In this region, the COS are moving slowly, but the initial state gluons are highly energetic. We integrate out the large scale mS and the match the diagrams in Fig. 1-(a) onto operators with SCET collinear fields describing the initial state gluons and the HSET fields describing the slowly moving COS in the final state. After this matching, the production of S+ and S− is accomplished via the operator depicted in Fig. 1-(b) which is LINT παs 2m3S

FACTORIZATION FOR COS PAIR PRODUCTION

RESUMMATION AND NUMERICAL RESULTS

2: Mass distribution of the scattering cross section for pp

Findings

CONCLUSIONS