MoEDAL search in the CMS beam pipe for magnetic monopoles produced via the Schwinger effect

TL;DR

This paper reports a search for magnetic monopoles produced in heavy-ion collisions at the LHC, using the CMS beam pipe as a trapping detector, setting new mass limits on monopoles with high magnetic charge.

Contribution

It introduces a novel search method utilizing the CMS beam pipe as a trapping volume and leverages ultra-high magnetic fields to set the first reliable mass limits on high-charge magnetic monopoles.

Findings

No magnetic monopoles were detected in the scanned beam pipe.

Established the strongest mass limits for monopoles with charges between 2 and 45 Dirac units.

Excluded monopoles with masses up to 80 GeV at 95% confidence level.

Abstract

We report on a search for magnetic monopoles (MMs) produced in ultraperipheral Pb--Pb collisions during Run-1 of the LHC. The beam pipe surrounding the interaction region of the CMS experiment was exposed to 184.07 \textmu b$^{-1}$ of Pb--Pb collisions at 2.76 TeV center-of-mass energy per collision in December 2011, before being removed in 2013. It was scanned by the MoEDAL experiment using a SQUID magnetometer to search for trapped MMs. No MM signal was observed. The two distinctive features of this search are the use of a trapping volume very close to the collision point and ultra-high magnetic fields generated during the heavy-ion run that could produce MMs via the Schwinger effect. These two advantages allowed setting the first reliable, world-leading mass limits on MMs with high magnetic charge. In particular, the established limits are the strongest available in the range between 2 and 45 Dirac units, excluding MMs with masses of up to 80 GeV at 95\% confidence level.