Measurement of exclusive $\gamma\gamma\rightarrow\mu^{+}\mu^{-}$ production at $\sqrt{s} = 7$~TeV

A measurement is reported of the exclusive two-photon production of muon pairs, $pp \rightarrow p \mu^{+}\mu^{-} p$, in proton-proton collisions at $\sqrt{s}= 7$~TeV for an integrated luminosity of $40$~pb$^{-1}$. For muon pairs with invariant mass above $11.5$~GeV, and with $p_T(\mu) > 4$~GeV and $\eta(\mu) < 2.1$, a fit to the $p_{T}(\mu^{+}\mu^{-})$ distribution results in a measured partial cross-section of $\sigma(pp \rightarrow p \mu^{+}\mu^{-} p) = 3.38^{+0.58}_{-0.55} (stat.) \pm 0.16 (syst.) \pm 0.14 (lumi)$~pb.