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
The process pp → p` +` −p (∗) , with ` +` − 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 √ s = 13 TeV. One of the two scattered protons is measured in the CMS-TOTEM precision proton spe...
Main Authors: | , , , , , |
---|---|
Format: | Article |
Language: | English English English |
Published: |
Springer Verlag
2018
|
Subjects: | |
Online Access: | http://irep.iium.edu.my/70412/ http://irep.iium.edu.my/70412/ http://irep.iium.edu.my/70412/ http://irep.iium.edu.my/70412/1/70412_Observation%20of%20proton-tagged%2C%20central%20%28semi%29exclusive_article.pdf http://irep.iium.edu.my/70412/7/70412_Observation%20of%20proton-tagged%2C%20central%20%28semi%29exclusive_scopus.pdf http://irep.iium.edu.my/70412/8/70412_Observation%20of%20proton-tagged%2C%20central%20%28semi%29exclusive_wos.pdf |
Summary: | The process pp → p`
+`
−p
(∗)
, with `
+`
− 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 √
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 µ
+µ
− and 8 e+e
− pairs with m(`
+`
−) > 110 GeV, and matching forward proton
kinematics, are observed, with expected backgrounds of 1.49 ± 0.07 (stat) ± 0.53 (syst) and
2.36 ± 0.09 (stat) ± 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 γγ collisions at the electroweak scale. This measurement
also demonstrates that CT-PPS performs according to the design specifications. |
---|