Abstract:
A measurement of the exclusive two-photon production of muon pairs in proton-proton collisions at $\sqrt{s}$ = 7 TeV, pp $\to$ p$\mu^+ \mu^−$p, is reported using data corresponding to an integrated luminosity of 40 pb$^{−1}$. For muon pairs with invariant mass greater than 11.5 GeV, transverse momentum $p_{\mathrm{T}} (\mu) >$ 4 GeV and pseudorapidity $| \eta(\mu) | <$ 2.1, a fit to the dimuon $p_{\mathrm{T}} (\mu^+\mu^-) $ distribution results in a measured cross section of $\sigma ( \mathrm{ p \to p \mu^+ \mu^- p }) =$ 338 $^{+058}_{-055}$ (stat.) $\pm$ 0.16 (syst.) $\pm$ 0.14 (lumi.) pb, consistent with the theoretical prediction evaluated with the event generator Lpair. The ratio to the predicted cross section is 083 $^{+058}_{-013}$ (stat.) $\pm$ 0.04 (syst.) $\pm$ 0.03 (lumi.). The characteristic distributions of the muon pairs produced via $\gamma\gamma$ fusion, such as the muon acoplanarity, the muon pair invariant mass and transverse momentum agree with those from the theory.
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