Measurement of the Shared Momentum Fraction z_g using Jet Reconstruction in p + p and Au + Au Collisions with STAR

Journal Article · 25 September 2017 · Nuclear Physics. A

DOI: https://doi.org/10.1016/j.nuclphysa.2017.07.004 · OSTI ID:1502368

Kauder, K. ^[1]

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1. Wayne State Univ., Detroit, MI (United States); Wayne State University

One key difference in current energy loss models lies in the treatment of the Altarelli-Parisi, AP, splitting functions. It has been shown that the shared momentum fraction, henceforth called Jet Splitting Function z_g as determined by the SoftDrop grooming process can be made a Sudakov-safe measurement of the symmetrized AP functions in p+p collisions. The STAR collaboration presents the first z_g measurements at $$ \sqrt{s}$$NN = 200 GeV in p+p and Au+Au collisions, where in Au+Au we use a set of di-jets with hard cores reconstructed with a 2 GeV/c constituent cut. For a jet resolution parameter of R = 0.4, these di-jet pairs were found to be significantly imbalanced with respect to p+p, yet regained balance when all soft constituents were included. As a result, we find that within uncertainties there are no signs of a modified Jet Splitting Function on trigger or recoil sides of this di-jet selection.

• Research Organization: Wayne State Univ., Detroit, MI (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: FG02-92ER40713
• OSTI ID: 1502368
• Journal Information: Nuclear Physics. A, Journal Name: Nuclear Physics. A Journal Issue: C Vol. 967; ISSN 0375-9474
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English