Электронный каталог

Статья

Hayrapetyan, A.
Observation of Enhanced Long-Rang Elliptic Anisotropies Inside High-Multiplicity Jets in pp Collisions at*%s=13 TeV / A.Hayrapetyan, S.Afanasiev, D.Budkouski, I.Golutvin, I.Gorbunov, V.Karjavine, V.Korenkov, N.Krasnikov, A.Lanev, A.Malakhov, V.Matveev, V.Palichik, V.Perelygin, M.Savina, V.Shalaev, S.Shmatov, S.Shulha, V.Smirnov, O.Teryaev, N.Voytishin, B.S.Yuldashev, A.Zarubin, I.Zhizhin, Z.Tsamalaidze, [CMS Collab.] // Physical Review Letters [Electronic resource]. – 2024. – Vol. 133, No. 14. – P. 142301. – URL: https://doi.org/10.1103/PhysRevLett.133.142301. – Bibliogr.: 68.

A search for collective effects inside jets produced in proton-proton collisions is performed via correlation measurements of charged particles using the CMS detector at the CERN LHC. The analysis uses data collected at a center-of-mass energy of √𝑠=13  TeV, corresponding to an integrated luminosity of 138  fb−1. Jets are reconstructed with the anti-𝑘T algorithm with a distance parameter of 0.8 and are required to have transverse momentum greater than 550 GeV and pseudorapidity |𝜂jet|<1.6. Two-particle correlations among the charged particles within the jets are studied as functions of the particles’ azimuthal angle and pseudorapidity separations (Δ⁢𝜙* and Δ⁢𝜂*) in a jet coordinate basis, where particles’ 𝜂*, 𝜙* are defined relative to the direction of the jet. The correlation functions are studied in classes of in-jet charged-particle multiplicity up to 𝑁j ch≈100. Fourier harmonics are extracted from long-range azimuthal correlation functions to characterize azimuthal anisotropy for |Δ⁢𝜂*|>2. For low-𝑁j ch jets, the long-range elliptic anisotropic harmonic, 𝑣* 2, is observed to decrease with 𝑁j ch. This trend is well described by Monte Carlo event generators. However, a rising trend for 𝑣* 2 emerges at 𝑁j ch≳80, hinting at a possible onset of collective behavior, which is not reproduced by the models tested. This observation yields new insights into the dynamics of jet evolution in the vacuum.



ОИЯИ = ОИЯИ (JINR)2024
Спец.(статьи,препринты) = С 346.2в - Взаимодействие протонов с протонами