Enhanced Deuteron Coalescence Probability in Jets.

Acharya, S, Adamová, D, Adler, A, Aglieri Rinella, G, Agnello, M, Agrawal, N, Ahammed, Z, Ahmad, S, Ahn, SU, Ahuja, I
et al (show 1030 more authors) (2023) Enhanced Deuteron Coalescence Probability in Jets. Physical review letters, 131 (4). 042301-.

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The transverse-momentum (p_{T}) spectra and coalescence parameters B_{2} of (anti)deuterons are measured in p-p collisions at sqrt[s]=13  TeV for the first time in and out of jets. In this measurement, the direction of the leading particle with the highest p_{T} in the event (p_{T}^{lead}>5  GeV/c) is used as an approximation for the jet axis. The event is consequently divided into three azimuthal regions, and the jet signal is obtained as the difference between the toward region, that contains jet fragmentation products in addition to the underlying event (UE), and the transverse region, which is dominated by the UE. The coalescence parameter in the jet is found to be approximately a factor of 10 larger than that in the underlying event. This experimental observation is consistent with the coalescence picture and can be attributed to the smaller average phase-space distance between nucleons in the jet cone as compared with the underlying event. The results presented in this Letter are compared to predictions from a simple nucleon coalescence model, where the phase-space distributions of nucleons are generated using pythia8 with the Monash 2013 tuning, and to predictions from a deuteron production model based on ordinary nuclear reactions with parametrized energy-dependent cross sections tuned on data. The latter model is implemented in pythia8.3. Both models reproduce the observed large difference between in-jet and out-of-jet coalescence parameters, although the almost flat trend of the B_{2}^{Jet} is not reproduced by the models, which instead give a decreasing trend.

Item Type: Article
Uncontrolled Keywords: ALICE Collaboration
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 02 Oct 2023 15:41
Last Modified: 02 Oct 2023 15:42
DOI: 10.1103/physrevlett.131.042301
Open Access URL: https://doi.org/10.1103/PhysRevLett.131.042301
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3173330