Photon-jet events as a probe of axionlike particles at the LHC

Daohan Wang,Lei Wu,Mengchao Zhang,Jin Min Yang

doi:10.1103/physrevd.104.095016

Abstract

Axionlike particles (ALPs) are predicted by many extensions of the Standard Model. When ALP mass lies in the range of MeV--GeV, the cosmology and astrophysics will be largely irrelevant. In this work, we investigate such light ALPs through the ALP-strahlung process $pp\ensuremath{\rightarrow}Va(\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma})$ at the 14 TeV LHC with an integrated luminosity of $3000\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ (high-luminosity LHC). With the photon-jet algorithm, we demonstrate that our approach can probe the mass range of ALPs, which has been inaccessible in previous LHC experiments. The obtained result can surpass the existing limits on ALP-photon coupling in the ALP mass range from 0.3 to 10 GeV.

Highlights

INTRODUCTIONLight pseudo-scalars, such as axionlike particles (ALPs), are theoretically well motivated
Searching for new particles is one of the crucial tasks in the LHC experiment
When axionlike particles (ALPs) masses are below the MeV scale, they are already subject to many constraints from cosmological and astrophysical observations [10,11]

Summary

INTRODUCTION

Light pseudo-scalars, such as axionlike particles (ALPs), are theoretically well motivated. The ALP masses and couplings to Standard Model (SM) particles are independent parameters. When ALP masses are below the MeV scale, they are already subject to many constraints from cosmological and astrophysical observations [10,11]. When ALPs become light, they can be highly boosted, and the two photons from the ALP decay are recognized as one object in the detector This will lead to an interesting signature “photon jet” at the LHC. We will focus on ALPs that only couple to the electroweak vector bosons with a mass in the MeV– GeV range. Such light electroweak ALPs have obtained an increasing amount of interest due to current collider data. Extend the LHC sensitivity to parameter space unreachable in previous studies

MODEL AND PHOTON JET

ALP-STRAHLUNG PROCESS AT THE LHC

CONCLUSIONS