Measurement of exclusive $\gamma\gamma\rightarrow W^+W^-$ production and search for exclusive Higgs boson production in $pp$ collisions at $\sqrt{s} = 8$ TeV using the ATLAS detector
Phys.Rev. D94 (2016) 032011
The collaboration

Abstract (data abstract)
ATLAS CERN-LHC. Measurements of exclusive electron muon events in ATLAS at 8 TeV are used to estimate the exclusive cross section for W+W-, put limits on anomolous quartic couplings (aQGCs), and limit the cross section for diffractive Higgs production. The fiducial region is defined as - |etaLepton| <2.5 - ptLepton >25 (second lepton >20 or >15 for Higgs study) - exclusivity no other track associated with the electron/muon intersection with pt >0.5 The luminosity is 20.2 (0.4) 1/fb at 8 TeV. Calibration of exclusivity is data based and e e and mu mu results agree with previous measurements. The results are - dimuons > 160 GeV/c2 ratio observed/elastic predicted 3.30 (0.22) (0.06) - WW sigmaB emuX (gamma gamma) 6.9 (2.2) (1.4) pb consistent with expectation - anomolous expect pt(emu) >120 expect 0.4 see 1, limits on dim 6 and 8 - Higgs selection expect 3 see 6, UL 95% 1.2 pb