Maria Zurek, Zhanwen Zhu, Recent STAR SPIN results I

Tuesday 23 Jun 2020, 11:00 → 12:00 US/Eastern

Measurement of transverse single spin asymmetries at forward rapidities by the STAR experiment  at √s = 200 and 500 GeV

Zhanwen Zhu, Shandong University

We present recent results of transverse single spin asymmetries (TSSA) for neutral pions using the Forward Meson Spectrometer at STAR at center of mass energies of 200 and 500 GeV in proton-proton collision. In order to separate the contribution of initial and final state effects at both energies, we also measured for the electromagnetic jet TSSA and the Collins asymmetry for neutral pions inside the electromagnetic jet. These results together provide rich information to understand the origin of neutral pion TSSA.

Longitudinal double-spin asymmetries for inclusive jets produced in √s = 200 GeV proton-proton collisions

Maria Żurek, Lawrence Berkeley National Laboratory

 

STAR measures double-spin asymmetries ALL in longitudinally polarized proton-proton collisions to determine the gluon helicity distribution ∆G(x,Q2). Previously published inclusive jet results based on √s = 200 GeV data collected in 2009 provided first evidence for positive gluon polarization for a momentum fraction x > 0.05 at a hard perturbative scale Q2 = 10 GeV2. This talk will present new preliminary results from 2015 data with an approximately twice larger figure of merit and correspondingly better precision.

ForSeminarV2.pdf

MariaZurekSeminarBNL.pdf