Exclusive dilepton and Upsilon production with CMS: a feasibility study

Abstract

Exclusive production of dileptons with no significant additional activity in the CMS detector occurs with high cross section in gamma-mediated processes at the LHC. A feasibility study based on a full CMS simulation concludes that selecting events with a single pair of back-to-back µ + µ − or e + e − provides a high-statistics calibration sample, e.g. for luminosity measurement and alignment of forward proton detectors. Photoproduction of Upsilon mesons, another copious source of exclusive dileptons, is also presented. Deep-Inelastic Scattering and Related Subjects,7-11 April 2008,London,United Kingdom Exclusive dilepton and Upsilon production with CMS: a feasibility study S. Ovyn, on behalf of the CMS Collaboration Université catholique de Louvain Center for Particle Physics and Phenomenolgy (CP3) B-1348, Louvain-la-Neuve, Belgium Presented at XVI International Workshop onExclusive production of dileptons with no significant additional activity in the cms detector occurs with high cross section in gamma-mediated processes at the lhc. A feasibility study based on a full cms simulation concludes that selecting events with a single pair of back-to-back µ + µ − or e + e − provides a high-statistics calibration sample, e.g. for luminosity measurement and alignment of forward proton detectors. Photoproduction of Upsilon mesons, another copious source of exclusive dileptons, is also presented.

Diffractive Υ production at the Tevatron and LHC

“…For the Tevatron, we approximate the angular acceptance of the CDF muon detector using θ min = 33.5 • , whilst for the DØ detector we take θ min = 15.4 • . At the LHC we assume, θ min = 7.7 • (see also [26]). In all cases we show results for P min t = 3 GeV and P min t = 4 GeV.…”

Exclusive photoproduction at the Fermilab Tevatron and CERN LHC within the dipole picture

“…Exclusive photoproduction processes will be important at the LHC, particularly if proton taggers are installed in the 420 m region [43]. Exclusive production of Υ mesons should be measured in the early days of LHC running, extending and improving the existing data from HERA, and providing valuable constraints on the shape of the dipole cross section or generalised gluon density [31,44]. It is very unlikely that exclusive Z 0 photoproduction will be observed at the Tevatron, and it remains to be seen whether this process is observable at the LHC given the low event rate.…”

Experimental Results on Diffraction

“…The CMS collaboration prepares the measurement of exclusive dilepton production based on the detection of centrally produced e + e − or µ + µ − pairs [17]. The main uncertainty in this analysis will be due to the inelastic background where one of the protons dissociates.…”