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Title: Observation of proton-tagged, central (semi)exclusive production of high-mass lepton pairs in pp collisions at 13 TeV with the CMS-TOTEM precision proton spectrometer

Abstract

The process pp$$\to\ell^+\ell^-$$p$$^{(*)}$$, with $$\ell^+\ell^-$$ a muon or an electron pair produced at midrapidity with mass larger than 110 GeV, has been observed for the first time at the LHC in pp collisions at $$\sqrt{s} =$$ 13 TeV. One of the two scattered protons is measured in the CMS-TOTEM precision proton spectrometer (CT-PPS), which operated for the first time in 2016. The second proton either remains intact or is excited and then dissociates into a low-mass state p$$^{*}$$, which is undetected. The measurement is based on an integrated luminosity of 9.4 fb$$^{-1}$$ collected during standard, high-luminosity LHC operation. A total of 12 $$\mu^+\mu^-$$ and 8 e$^+$e$^-$ pairs with $$m(\ell^{+}\ell^{-}) >$$ 110 GeV, and matching forward proton kinematics, are observed, with expected backgrounds of 1.49 $$\pm$$ 0.07 (stat) $$\pm$$ 0.53 (syst) and 2.36 $$\pm$$ 0.09 (stat) $$\pm$$ 0.47 (syst), respectively. This corresponds to an excess of more than five standard deviations over the expected background. The present result constitutes the first observation of proton-tagged $$\gamma\gamma$$ collisions at the electroweak scale. This measurement also demonstrates that CT-PPS performs according to the design specifications.

Authors:
;
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Org.:
CMS; TOTEM
OSTI Identifier:
1454715
Report Number(s):
FERMILAB-PUB-18-278-CMS; CMS-PPS-17-001; TOTEM 2018-001; CERN-EP-2018-014; arXiv:1803.04496; TOTEM-2018-001
1662293
DOE Contract Number:
AC02-07CH11359
Resource Type:
Journal Article
Resource Relation:
Journal Name: JHEP
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Sirunyan, Albert M, and et al. Observation of proton-tagged, central (semi)exclusive production of high-mass lepton pairs in pp collisions at 13 TeV with the CMS-TOTEM precision proton spectrometer. United States: N. p., 2018. Web.
Sirunyan, Albert M, & et al. Observation of proton-tagged, central (semi)exclusive production of high-mass lepton pairs in pp collisions at 13 TeV with the CMS-TOTEM precision proton spectrometer. United States.
Sirunyan, Albert M, and et al. Mon . "Observation of proton-tagged, central (semi)exclusive production of high-mass lepton pairs in pp collisions at 13 TeV with the CMS-TOTEM precision proton spectrometer". United States. doi:. https://www.osti.gov/servlets/purl/1454715.
@article{osti_1454715,
title = {Observation of proton-tagged, central (semi)exclusive production of high-mass lepton pairs in pp collisions at 13 TeV with the CMS-TOTEM precision proton spectrometer},
author = {Sirunyan, Albert M and et al.},
abstractNote = {The process pp$\to\ell^+\ell^-$p$^{(*)}$, with $\ell^+\ell^-$ a muon or an electron pair produced at midrapidity with mass larger than 110 GeV, has been observed for the first time at the LHC in pp collisions at $\sqrt{s} =$ 13 TeV. One of the two scattered protons is measured in the CMS-TOTEM precision proton spectrometer (CT-PPS), which operated for the first time in 2016. The second proton either remains intact or is excited and then dissociates into a low-mass state p$^{*}$, which is undetected. The measurement is based on an integrated luminosity of 9.4 fb$^{-1}$ collected during standard, high-luminosity LHC operation. A total of 12 $\mu^+\mu^-$ and 8 e$^+$e$^-$ pairs with $m(\ell^{+}\ell^{-}) >$ 110 GeV, and matching forward proton kinematics, are observed, with expected backgrounds of 1.49 $\pm$ 0.07 (stat) $\pm$ 0.53 (syst) and 2.36 $\pm$ 0.09 (stat) $\pm$ 0.47 (syst), respectively. This corresponds to an excess of more than five standard deviations over the expected background. The present result constitutes the first observation of proton-tagged $\gamma\gamma$ collisions at the electroweak scale. This measurement also demonstrates that CT-PPS performs according to the design specifications.},
doi = {},
journal = {JHEP},
number = ,
volume = ,
place = {United States},
year = {Mon Mar 12 00:00:00 EDT 2018},
month = {Mon Mar 12 00:00:00 EDT 2018}
}