Analysis of the apparent nuclear modification in peripheral Pb–Pb collisions at 5.02 TeV
Abstrakti
Charged-particle spectra at midrapidity are measured in Pb–Pb collisions at the centre-of-mass energy per nucleon–nucleon pair TeV and presented in centrality classes ranging from most central (0–5%) to most peripheral (95–100%) collisions. Possible medium effects are quantified using the nuclear modification factor () by comparing the measured spectra with those from proton–proton collisions, scaled by the number of independent nucleon–nucleon collisions obtained from a Glauber model. At large transverse momenta (), the average is found to increase from about 0.15 in 0–5% central to a maximum value of about 0.8 in 75–85% peripheral collisions, beyond which it falls off strongly to below 0.2 for the most peripheral collisions. Furthermore, initially exhibits a positive slope as a function of in the 8–20 interval, while for collisions beyond the 80% class the slope is negative. To reduce uncertainties related to event selection and normalization, we also provide the ratio of in adjacent centrality intervals. Our results in peripheral collisions are consistent with a PYTHIA-based model without nuclear modification, demonstrating that biases caused by the event selection and collision geometry can lead to the apparent suppression in peripheral collisions. This explains the unintuitive observation that is below unity in peripheral Pb–Pb, but equal to unity in minimum-bias p–Pb collisions despite similar charged-particle multiplicities.
Päätekijä
Aineistotyyppi
Artikkelit
Tutkimusartikkeli
Julkaistu
2019
Sarja
Aiheet
Julkaisu tutkimustietojärjestelmässä
Julkaisija
Elsevier
Julkaisun pysyvä osoite
https://urn.fi/URN:NBN:fi:jyu-201906123164Käytä tätä linkitykseen
Vertaisarvioinnin tila
Vertaisarvioitu
ISSN
0370-2693
DOI
https://doi.org/10.1016/j.physletb.2019.04.047
Kieli
englanti
Julkaisussa
Physics Letters B
Viite
- ALICE Collaboration. (2019). Analysis of the apparent nuclear modification in peripheral Pb–Pb collisions at 5.02 TeV. Physics Letters B, 793, 420-432. https://doi.org/10.1016/j.physletb.2019.04.047
Copyright© 2019 Conseil Européen pour la Recherche Nucléaire.