Speaker
Description
Relativistic heavy-ion collisions offer a unique environment for exploring quantum interference at an unprecedented femtometer scale through photon-nuclear interactions in photoproduction. In exclusive $\pi^{+}\pi^{-}$ production, the resonance and continuum $\pi^{+}\pi^{-}$ components arise from distinct production mechanisms in the $\gamma {\rm A}$ interaction. The continuum $\pi^{+}\pi^{-}$ photoproduction is dominated by Drell-S$\ddot{{\rm o}}$ding process, in which a virtual $\pi^{+}/\pi^{-}$ is diffraction-scattered on the nucleus. The $\sim$5% difference in the elastic scattering cross sections of $\pi^{-} {\rm A}$ and $\pi^{+} {\rm A}$ around a $\gamma {\rm p}$ center-of-mass energy of approximately 12 GeV in photoproduction in 200 GeV Au+Au collisions may result in destructive interference. In contrast to $\rho^{0}$ photoproduction, the Entanglement Enabled Spin Interference (EESI) in Drell-S$\ddot{{\rm o}}$ding process may differ due to the absence of the intermediate $\rho^{0}$ and the specific dynamics of the virtual pion-nucleus interaction.
In this poster, we will present the first measurement of the diffractive $p_{T}$ spectrum and the spin interference pattern through ${\rm A_{2\Delta\phi}}$ for the Drell-S$\ddot{{\rm o}}$ding process in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV at STAR. The results indicate an obvious difference in $p_{T}$ spectrum compared to $\rho^{0}$ photoproduction. We also observe ${\rm A_{2\Delta\phi}}$ with no clear mass dependence for $p_{T} < 0.1$ GeV/c and a notablely stronger interference at the same ${\rm M_{\pi^{+}\pi^{-}}}$ in the Drell-S$\ddot{{\rm o}}$ding process compared to $\rho^{0}$ photoproduction, which provides a unique opportunity to explore the effect of production mechanism on the EESI.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | STAR Collaboration |
