Speaker
Description
We present measurements of azimuthal acoplanarity based on direct photon ($\gamma$) and $\pi^{0}$-triggered semi-inclusive recoil jet distributions in central Au+Au and $p+p$ collisions at $\sqrt{s_{\rm NN}}=200$ GeV, using datasets with integrated luminosity of 3.9 nb$^{-1}$ and 23 pb$^{-1}$, respectively.
This observable may probe jet wake effects and Moliere scattering off of quasi-particles in the QGP. Jets are reconstructed from charged particles using anti-k$_{T}$ with R=0.2 and 0.5, with uncorrelated background corrected using event mixing. The $\gamma$ and $\pi^{0}$ triggers have transverse energy in the interval [11,15] GeV, and recoil jets are reported in the $p_T$ interval [10,20] GeV/c. Marked medium-induced acoplanarity is observed with both triggers for recoil jets with R=0.5 but not R=0.2, similar to a recent measurement at the LHC. We discuss the insight that these observations provide into the nature of the jet-medium interaction and the response of the QGP to excitation. The measurements will also be compared to theoretical calculations.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | STAR |
