Search for Magnetic Monopoles in √s=7 TeV pp Collisions with the ATLAS Detector

This Letter presents a search for magnetic monopoles with the ATLAS detector at the CERN Large
Hadron Collider using an integrated luminosity of 2:0 fb1 of pp collisions recorded at a center-of-mass
energy of pffisffiffi ¼ 7 TeV. No event is found in the signal region, leading to an upper limit on the production
cross section at 95% confidence level of 1:6= fb for Dirac magnetic monopoles with the minimum unit
magnetic charge and with mass between 200 GeVand 1500 GeV, where is the monopole reconstruction
efficiency. The efficiency is high and uniform in the fiducial region given by pseudorapidity jj < 1:37
and transverse kinetic energy 600–700monopoles of mass 200 GeV, whereas the minimum value of 600 GeV is applicable for higher mass
monopoles. Therefore, the upper limit on the production cross section at 95% confidence level is 2 fb in
this fiducial region. Assuming the kinematic distributions from Drell-Yan pair production of spin-1=2
Dirac magnetic monopoles, the efficiency is in the range 1%–10%, leading to an upper limit on the cross
section at 95% confidence level that varies from 145 fb to 16 fb for monopoles with mass between
200 GeV and 1200 GeV. This limit is weaker than the fiducial limit because most of these monopoles lie
outside the fiducial region.