Exclusive and diffractive ${\mu }^{+}{\mu }^{-}$ production in $pp$ collisions at the LHC

In this paper, we estimate the production of dimuons (${\mu }^{+}{\mu }^{-}$) in exclusive photon-photon ($\gamma \gamma$) and diffractive Pomeron-Pomeron ($IPIP$), Pomeron-Reggeon ($IPIR$), and Reggeon-Reggeon ($IRIR$) interactions in $pp$ collisions at the LHC energy. The invariant mass, rapidity, and tranverse momentum distributions are calculated using the forward physics Monte Carlo (FPMC), which allows us to obtain realistic predictions for the dimuon production with two leading intact hadrons. In particular, predictions taking into account the CMS and LHCb acceptances are presented. Moreover, the contribution of the single diffraction for the dimuon production also is estimated. Our results demonstrate that the experimental separation of these different mechanisms is feasible. In particular, the events characterized by pairs with large squared transverse momentum are dominated by diffractive interactions, which allows us to investigate the underlying assumptions present in the description of these processes.

Figure 1

The dimuon production in exclusive $\gamma \gamma$ interactions (left panel) and in double (central panel) and single (right panel) diffractive processes.

Figure 2

Contribution of the $IPIP$, $IPIR$, and $IRIR$ mechanisms for the invariant mass (left panel), squared pair transverse momentum (central panel) and pair rapidity (right panel) distributions considering the double diffractive ${\mu }^{+}{\mu }^{-}$ production. The sum of the contributions, denoted by DD, is represented by solid blue line.

Figure 3

Contribution of the $IPp$ and $IRp$ mechanisms for the invariant mass (left panel), squared pair transverse momentum (central panel) and pair rapidity (right panel) distributions considering the single diffractive ${\mu }^{+}{\mu }^{-}$ production. The sum of the contributions, denoted by SD, is represented by the dashed black line.

Figure 4

Comparison between the predictions for the exclusive, single and double diffractive dimuon production.

Figure 5

Comparison between the predictions for the exclusive, single and double diffractive dimuon production after the implementation of the elastic selection criteria discussed in the text.

Figure 6

Comparison between the predictions for the exclusive, single and double diffractive dimuon production considering events with $p_T^2>2{\mathrm{GeV}}^2$ and implementation of the cuts discussed in the text.