Speaker
Description
The transversity distribution, $h^q_1(x)$, describes transversely polarized quarks inside a transversely polarized nucleon. As $h^q_1(x)$ is chiral-odd, it can only be accessed via a process where it couples to another chiral-odd function, such as the spin-dependent interference fragmentation function (IFF), in $p^\uparrow p$ collisions. The coupling of $h^q_1(x)$ and IFF yields an experimentally measurable di-hadron correlation asymmetry, $A_{UT}$. To access $h^q_1(x)$ at high $Q^2$, where the QCD calculation is well understood, precise measurement of $A_{UT}$ at high center-of-mass energies, $\sqrt s$, is crucial. Previously, the STAR experiment at RHIC has measured non-zero $A_{UT}$ using $p^\uparrow p$ data at $\sqrt s= 200$ GeV recorded in 2006 with an integrated luminosity of $1.6$ pb$^{-1}$ and $\sqrt s= 500$ GeV recorded in 2011 with an integrated luminosity of $25$ pb$^{-1}$. In 2015 and 2017, STAR collected additional $\sim 52$ pb$^{-1}$ of $p^\uparrow p$ data at $\sqrt s=200$ GeV and $\sim 350$ pb$^{-1}$ of $p^\uparrow p$ data at $\sqrt s=510$ GeV, which will significantly improve the statistical precision of $A_{UT}$ measurement and thus further constrain global fits of $h^q_1(x)$, especially for $0.07
| Submitted on behalf of a Collaboration? | Yes |
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