Evidence for Nonlinear Gluon Effects in QCD and Their Mass Number Dependence at STAR
Journal Article
·
· Physical Review Letters
The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di-π0s produced at forward pseudorapidities (2.6<η<4.0) in p+p, p+Al, and p+Au collisions at a center-of-mass energy of 200 GeV. We observe a clear suppression of the correlated yields of back-to-back π0 pairs in p+Al and p+Au collisions compared to the p+p data. The observed suppression of back-to-back pairs as a function of transverse momentum suggests nonlinear gluon dynamics arising at high parton densities. Furthermore, the larger suppression found in p+Au relative to p+Al collisions exhibits a dependence of the saturation scale $$Q^{2}_{s}$$ on the mass number A . A linear scaling of the suppression with A1/3 is observed with a slope of -0.09±0.01.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States); Texas A & M Univ., College Station, TX (United States); Univ. of California, Los Angeles, CA (United States)
- Sponsoring Organization:
- Bundesanstalt fur Materialforschung und prufung (BAM); Chinese Academy of Sciences (CAS); Croatian Ministry of Science, Education and Sports; Czech Science Foundation (GACR); Government of India, Department of Atomic Energy; Government of India, Department of Science and Technology; Helmholtz Association of German Research Centres; Japan Society for the Promotion of Science (JSPS); Ministry of Education, Culture, Sports, Science and Technology (MEXT); Ministry of Science and Technology of the People's Republic of China; National Natural Science Foundation of China (NSFC); National Research Foundation (NRF) of Korea; National Science Centre of Poland (NCN); National Science Foundation (NSF); Rosatom State Atomic Energy Corporation; Russian Federation, Ministry of Education and Science; USDOE Office of Science (SC), Nuclear Physics (NP)
- Contributing Organization:
- STAR Collaboration
- Grant/Contract Number:
- AC02-06CH11357; FG02-88ER40424; SC0012704; SC0017982
- OSTI ID:
- 1889856
- Alternate ID(s):
- OSTI ID: 1903271
OSTI ID: 1903336
OSTI ID: 1903339
OSTI ID: 1905073
- Report Number(s):
- BNL-223208-2022-JAAM
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 9 Vol. 129; ISSN 0031-9007
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English