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Azimuthal correlations in Z +jets events in proton-proton collisions at
A Tumasyan1,2, W Adam3, J W Andrejkovic3
1Yerevan Physics Institute, Yerevan, Armenia.
The European Physical Journal. C, Particles and Fields
|August 14, 2023
Summary
This study measured Z bosons with jets in proton-proton collisions at the LHC. Results show multiple parton interactions are crucial for accurately describing low transverse momentum regions.
Area of Science:
- High Energy Physics
- Particle Physics
- Quantum Chromodynamics
Background:
- The Standard Model of particle physics describes fundamental particles and forces.
- Understanding Z boson production in association with jets provides insights into quantum chromodynamics (QCD).
- Proton-proton collisions at the Large Hadron Collider (LHC) offer a unique environment to study these interactions.
Purpose of the Study:
- To measure the production of Z bosons in association with jets.
- To investigate jet multiplicity and azimuthal correlations in different Z boson momentum regions.
- To compare experimental data with theoretical predictions from leading and next-to-leading order calculations.
Main Methods:
- Utilized data from the CMS experiment at the LHC, corresponding to an integrated luminosity of 36.3 fb^-1.
- Measured jet multiplicity for jets with transverse momentum (pT) ranging from below 10 GeV to above 100 GeV.
- Analyzed azimuthal correlations between the Z boson and leading jets, and between the two leading jets.
Main Results:
- Measurements of jet multiplicity were performed across various Z boson transverse momentum (pT) regions.
- Azimuthal correlations were studied in three distinct pT regions.
- Theoretical predictions, particularly those incorporating transverse-momentum dependent parton distributions and parton showers, showed good agreement in regions with limited multiple parton interactions and low jet multiplicities.
Conclusions:
- Multiple parton interactions (MPI) effects are significant and necessary for accurate descriptions of measured spectra, especially in low pT regions.
- The study provides valuable data for refining theoretical models of QCD processes at the LHC.
- This research contributes to a deeper understanding of the complex dynamics governing particle collisions.
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