English

Exclusive processes in pp collisions in CMS

High Energy Physics - Experiment 2019-08-13 v1

Abstract

We report the results on the searches of exclusive production of low- and high-mass pairs with the Compact Muon Solenoid (CMS) detector in proton-proton collisions at s\sqrt{s} = 7 TeV. The analyses comprise the central exclusive γγ\gamma\gamma production, the exclusive two-photon production of dileptons, e+ee^{+}e^{-} and μ+μ\mu^{+}\mu^{-}, and the exclusive two-photon production of WW pairs in the asymmetric e±μe^{\pm}\mu^{\mp} decay channel. No diphotons candidates are observed in data and an upper limit on the cross section is set to 1.18 pb with 95% confidence level for ET(γ)>E_{T}(\gamma)> 5.5 GeV and η(γ)<|\eta(\gamma)|< 2.5. In the measurement of exclusive dilepton production, seventeen e+ee^{+}e^{-} candidates are observed in data with ET(e)>E_{T}(e)> 5.5 GeV and η(e)<|\eta(e)|< 2.5, and the cross section for the exclusive dimuon production is set to σ(pppμ+μp)=3.380.55+0.58\sigma(pp\to p\,\mu^{+}\mu^{-}\,p)=3.38^{+0.58}_{-0.55} (stat.) ±\pm 0.16 (syst.) ±\pm 0.14 (lumi.) pb for m(μ+μ)>m(\mu^{+}\mu^{-})> 11.5 GeV, pT(μ)>p_{\textrm{T}}(\mu)> 4 GeV and η(μ)<|\eta(\mu)|< 2.1, both in agreement with the theoretical predictions. For high-mass systems, two events are observed in data for the exclusive two-photon production of WW pairs for pT(μ)>p_{\textrm{T}}(\mu)> 4 GeV, η(μ)<|\eta(\mu)|< 2.4 and m(e±μ)>m(e^{\pm}\mu^{\mp})> 20 GeV. Moreover, the study of the tail of the dilepton transverse momentum distribution resulted in model-independent upper limits for the anomalous quartic gauge couplings, which are of the order of 104^{-4}.

Keywords

Cite

@article{arxiv.1310.5327,
  title  = {Exclusive processes in pp collisions in CMS},
  author = {Gustavo G. da Silveira},
  journal= {arXiv preprint arXiv:1310.5327},
  year   = {2019}
}

Comments

7 pages, 6 figures, presented at the XXI International Workshop on Deep-Inelastic Scattering and Related Subjects, April 2013, Marseille, France

R2 v1 2026-06-22T01:50:23.933Z