Di-$$\pi^0$$ correlations in p+p, p+Al and p+Au collisions at $$\sqrt{s_{NN}}$$ = 200 GeV at STAR

Journal Article · Tue Jul 12 04:00:00 EDT 2022 · SciPost Physics Proceedings

DOI:https://doi.org/10.21468/SciPostPhysProc.8.043· OSTI ID:1875939

Chu, Xiaoxuan ^[1]

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1. Brookhaven National Laboratory

The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di- \pi^0 ${\pi }^0$ produced at forward pseudorapidity ( 2.6<\eta<4.0 $2.6<\eta <4.0$ ) in p+ $p+$ p $p$ , p+ $p+$ \mathrm{Al} $Al$ and p+ $p+$ \mathrm{Au} $Au$ collisions at a center-of-mass energy per nucleon-nucleon pair of 200 GeV. A clear suppression of the correlated away-side yields is observed in p+ $p+$ \mathrm{Au} $Au$ and for the first time in p+ $p+$ \mathrm{Al} $Al$ collisions, compared with the p $p$ + $+$ p $p$ data. The enhanced suppression found in p+ $p+$ \mathrm{Au} $Au$ with respect to p+ $p+$ \mathrm{Al} $Al$ collisions exhibits the saturation scale ( Q_s^2 $Q_s^2$ ) dependence on the mass number A $A$ . The observed suppression of back-to-back pairs as a function of event activity and transverse momentum points to non-linear gluon dynamics arising at high parton densities.

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0012704
• OSTI ID: 1875939
• Journal Information: SciPost Physics Proceedings, Journal Name: SciPost Physics Proceedings Journal Issue: 8; ISSN 2666-4003
• Publisher: Stichting SciPost
• Country of Publication: Netherlands
• Language: English