Search for magnetic monopoles with the MoEDAL forward trapping detector in 2.11 fb−1 of 13 TeV proton–proton collisions at the LHC

B S Acharya ,K Sliwa ,S Baines ,Ann M Hirt ,O Vives ,P Mermod ,Gordon W Semenoff ,V Vento ,A Korzenev ,A Widom ,M Campbell ,N Mauri ,Mariana Frank ,J Hays ,Nikolaos Mavromatos ,Guido Alexander Willems ,C Leroy ,L Caramete ,Ji Hye Yoon ,D.-W Kim ,S Pospı́šil ,R Orava ,B Parker ,Arttu Rajantie ,A J Bevan ,V Popa ,J A Tuszyński ,I Ostrovskiy ,M Pozzato ,Jean Alexandre ,H Brânzaş ,R Soluk ,Z Sahnoun ,A E Lionti ,V A Mitsou ,A De Roeck ,P Beneš ,G Sirri ,Malcolm Fairbairn ,B Bergmann ,John Ellis ,Roberto Ruiz De Austri ,J Swain ,K Kinoshita ,A Shaa ,A Margiotta ,D Felea ,S Sarkar ,M Spurio ,L Patrizii ,M De Montigny ,D Lacarrère ,M Tenti ,J L Pinfold ,S Cecchini ,J Janecek ,J Mamuzic ,V Togo ,J Bernabéu ,C García ,A Santra ,G Levi ,S.c Lee ,D Frekers ,Mairi Sakellariadou ,G E Păvălaş ,Y N Srivastava ,Z Vykydal ,M Suk ,I S Zgura

doi:10.1016/j.physletb.2018.05.069

Abstract

We update our previous search for trapped magnetic monopoles in LHC Run 2 using nearly six times more integrated luminosity and including additional models for the interpretation of the data. The MoEDAL forward trapping detector, comprising 222 kg of aluminium samples, was exposed to 2.11 fb−1 of 13 TeV proton–proton collisions near the LHCb interaction point and analysed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to the Dirac charge or above are excluded in all samples. The results are interpreted in Drell–Yan production models for monopoles with spins 0, 1/2 and 1: in addition to standard point-like couplings, we also consider couplings with momentum-dependent form factors. The search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.

Highlights

The magnetic monopole is motivated by the symmetry between electricity and magnetism, by grand-unification theories [1,2,3,4], and by the fundamental argument advanced by Dirac that its existence would explain why electric charge is quantised [5]
This paper presents a new search with the MoEDAL forward monopole trapping detector [24], using the same trapping array with both 2015 and 2016 exposures at LHC point-8
The aluminium elements of the MoEDAL trapping detector exposed to 13 TeV LHC collisions in 2015 and 2016 were scanned using a SQUID-based magnetometer to search for the presence of trapped magnetic charge

Summary

Introduction

The magnetic monopole is motivated by the symmetry between electricity and magnetism, by grand-unification theories [1,2,3,4], and by the fundamental argument advanced by Dirac that its existence would explain why electric charge is quantised [5]. To extract mass limits and compare results from different experiments, in absence of a better approach, the custom is to use cross sections computed from specific pair-production models such as Drell–Yan (DY) at leading order, with the caveat that the coupling of the monopole to the photon is so large that perturbative calculations are not expected to be reliable. For this reason it is preferable to interpret the search using as many different but theoretically well predicated models as possible. The setup and conditions of exposure are identical to those used in the previous search [24]

Magnetometer measurements

Interpretation in pair-production models

Findings

Conclusions