Searching for axionlike particles with low masses in pPb and PbPb collisions

V P Gonçalves,D E Martins,M S Rangel

doi:10.1140/epjc/s10052-021-09314-2

Abstract

The production of axionlike particles (ALPs) with small masses in ultraperipheral Pb–p and Pb–Pb collisions at the LHC is investigated. The cross section and kinematical distributions associated to the diphoton final state produced in the gamma gamma rightarrow a rightarrow gamma gamma subprocesses are estimated considering a realistic set of kinematical cuts. A detailed analysis of the backgrounds is performed and the expected sensitivity to the ALP production is derived. Our results demonstrate that a future experimental analysis of the exclusive diphoton production for the forward rapidities probed by the LHCb detector can improve the existing exclusion limits on the ALP–photon coupling in the mass range 2 GeV le m_a le 5 GeV.

Highlights

1 2 μναβ Fαβ, which implies that axionlike particles (ALPs) can be produced by the photon–photon fusion and can decay into a diphoton system, as represented in Fig. 1a, where the incident particles are assumed as source of photons
In the exploratory study performed in Ref. [17], we have demonstrated that a forward detector, as the LHCb, is ideal to probe an ALP with small mass, which is a mass region of difficult experimental access for the ATLAS and CMS detectors due to restrictions on the photon reconstructive capabilities
One of the gPoba–lspocfothlliissiloenttseraits√tosennxt=end8.t1heTaenVa.lMysoisrefoovr eurl,trwapeecroipmhpelrea-l ment the previous study for Pb–Pb collisions by presenting the results for a larger number of combinations of ALP mass and coupling, with a special focus on the low mass region ma 5 GeV and forward rapidities, which can be reached by the LHCb detector

Summary

Pb γ γ

ALP production in the kinematical range probed by the LHCb detector, we will select events where photons are produced in the rapidity range 2.0 < |η(γ 1, γ 2)| < 4.5 with 0 extra tracks with pT > 0.1 GeV in the range 5.5 < |η| < 8.0, which corresponds to the HERSCHEL acceptance installed in the LHCb experiment [28].

Predictions for the cross sections for the exclusive diphoton production in

These results indicate that a future analysis by the LHCb