Dipole moment dark matter at the LHC

Vernon Barger,Wai-Yee Keung,Danny Marfatia,Po-Yan Tseng

doi:10.1016/j.physletb.2012.09.036

Abstract

Monojet and monophoton final states with large missing transverse energy (E̸T) are important for dark matter (DM) searches at colliders. We present analytic expressions for the differential cross sections for the parton-level processes, qq¯(qg)→g(q)χχ¯ and qq¯→γχχ¯, for a neutral DM particle with a magnetic dipole moment (MDM) or an electric dipole moment (EDM). We collectively call such DM candidates dipole moment dark matter (DMDM). We also provide monojet cross sections for scalar, vector and axial-vector interactions. We then use ATLAS/CMS monojet+E̸T data and CMS monophoton+E̸T data to constrain DMDM. We find that 7 TeV LHC bounds on the MDM DM–proton scattering cross section are about six orders of magnitude weaker than on the conventional spin-independent cross section.

Highlights

Collider data have provided an important avenue for dark matter (DM) searches, especially for candidates lighter than about 10 GeV [1,2,3], for which direct detection experiments have diminished sensitivity due to the small recoil energy of the scattering process
The final states that have proven to be effective for DM studies at colliders are those with a single jet or single photon and large missing transverse energy ( ET ) or transverse momentum
Our goal is study these signatures for DM that possesses a magnetic dipole moment (MDM) or an electric dipole moment (EDM) [4]; earlier work can be found in Ref. [5]

Summary

INTRODUCTION

Collider data have provided an important avenue for dark matter (DM) searches, especially for candidates lighter than about 10 GeV [1,2,3], for which direct detection experiments have diminished sensitivity due to the small recoil energy of the scattering process. Current assumption-dependent bounds on spin-dependent DM-nucleon scattering from LHC data, obtained using an effective field theory framework, are comparable or even superior to those from direct detection experiments for DM lighter than a TeV [2, 3]. The DM may be a Dirac fermion, but not a Majorana fermion We refer to these DM candidates as dipole moment dark matter (DMDM). We place bounds on the MDM DM-proton scattering cross section

PRODUCTION CROSS SECTIONS

CONSTRAINTS

SCATTERING CROSS SECTIONS