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Observation of Top Quark Production in Proton-Nucleus Collisions
A M Sirunyan1, A Tumasyan1, W Adam2
1Yerevan Physics Institute, Yerevan, Armenia.
Physical Review Letters
|December 30, 2017
Summary
The CMS experiment observed top quark production in proton-lead collisions for the first time. This groundbreaking discovery at the LHC provides crucial data for understanding particle physics at high energies.
Area of Science:
- High Energy Physics
- Particle Physics
- Quantum Chromodynamics
Background:
- Top quarks are the heaviest known elementary particles.
- Studying top quark production in proton-nucleus collisions offers insights into the strong nuclear force.
- Previous studies focused on proton-proton collisions.
Purpose of the Study:
- To report the first observation of top quark production in proton-nucleus collisions.
- To measure the cross section of top quark pair production in proton-lead interactions.
- To compare experimental results with theoretical predictions from perturbative quantum chromodynamics.
Main Methods:
- Utilized proton-lead collision data from the CMS experiment at the CERN Large Hadron Collider (LHC).
- Analyzed data at a nucleon-nucleon center-of-mass energy of 8.16 TeV.
- Selected events with one isolated electron or muon and at least four jets, using an integrated luminosity of 174 nb^{-1}.
Main Results:
- Observed a significant signal for top quark pair (ttbar) production with a significance exceeding 5 standard deviations.
- Measured the ttbar production cross section to be 45 ± 8 nb.
- The observed cross section is consistent with theoretical predictions.
Conclusions:
- The first observation of top quark production in proton-nucleus collisions has been established.
- The measurement provides valuable data for refining theoretical models of quantum chromodynamics.
- This result opens new avenues for exploring particle interactions in nuclear environments.
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