XXVIII International Workshop on Deep-Inelastic Scattering and Related Subjects

Transverse Spin Dependent Azimuthal Correlations of Charged hadrons(s) in p↑+p Collisions at s=200 GeV

14 Apr 2021, 08:18

18m

Virtual (Stony Brook, NY)

Contributed Talk Spin Physics Spin Physics

Speaker

Babu Pokhrel (Temple University)

Description

The transversity distribution function, $h_1^q(x)$, a leading twist parton distribution function, is a fundamental component of the spin structure of the nucleon. $h_1^q(x)$ describes the distributions of transversely polarized quarks inside a transversely polarized nucleon, where x is the longitudinal8momentum fraction of the proton carried by quark q. It is loosely constrained by global fits. Being chiral odd, $h_1^q(x)$ can be accessed only when it is coupled with another chiral-odd partner, such as the spin-dependent Collins fragmentation function (FF) or the interference fragmentation function (IFF), which serves as a quark polarimeter. In transversely polarized proton-proton ($p^{\uparrow }p$) collisions, the resulting azimuthal correlation between the spin of the fragmenting quark and the final state single charged hadron in jets (involving Collins FF) or di-hadron (involving IFF) can be measured, which are sensitive to quark transversity. The STAR experiment at RHIC has previously measured IFF asymmetries for ${\pi }^{+}{\pi }^{-}$ pairs using $p^{\uparrow }p$ collision data from 2006 at $\sqrt{s}$= 200 GeV ($\int Ldt$ = 1.8 $p{b}^{-1}$) and from 2011 at $\sqrt{s}$= 500 GeV ($\int Ldt$ = 25 $p{b}^{-1}$) and Collins asymmetries for charged pions within jets from 2011 at $\sqrt{s}$= 500 GeV. Non-zero IFF and Collins asymmetries were reported which are consistent with predictions based on global analyses of $e^{+}{e}^{-}$ and SIDIS data. In 2012 and 2015, STAR collected $\sim$ 14 $p{b}^{-1}$ $\sim$ 48 $p{b}^{-1}$ of $p^{\uparrow }p$ data at $\sqrt{s}$ = 200 GeV, respectively. These datasets provide the most precise measurements of the Collins and IFF asymmetries in $p^{\uparrow }p$ collisions at $\sqrt{s}$= 200 GeV to date, especially at the quark momentum fractions 0.1< x <0.4. We will present preliminary results for Collins asymmetries of identified pions, kaons, and protons in jets based on 2012 and 2015 $p^{\uparrow }p$ datasets and the status update for IFF asymmetries based on 2015 $p^{\uparrow }p$ dataset at $\sqrt{s}$= 200 GeV.

Presentation materials

DIS2021_IFFCollinsPrelm_Apr14.pdf

Youtube Link