Beam-energy dependence of spatial and temporal characteristics of shape-selected events in Au+Au collisions at the Relativistic Heavy Ion Collider(RHIC)

Newly measured two-pion Hanbury Brown and Twiss (HBT) radii have been made for shape-engineered events using data from the STAR experiment. These correlations leverage the HBT effect to allow investigation into how shape-engineering manifests itself within the spatial and temporal characteristics of the systems produced in relativistic heavy-ion collisions. Measureable changes in the HBT radii $\mathrm{R_{out}}$, $\mathrm{R_{side}}$ and $\mathrm{R_{long}}$ due to shape-engineering would be indicative of a change in the expansions dynamics of the system--ultimately helping to link initial state shape with final state measurements. Shape selection was accomplished via cuts on the distributions of the second-order flow vector $Q_2$ \footnote{J. Schukraft, A. Timmins, and S. A. Voloshin, Phys.Lett. B719, 394 (2013)}. Selected events, characterized with larger magnitudes of $Q_{2}$, indicate a systematic decrease for $R_{long}$ and $R_{out}$ with little, if any, change for $R_{side}$. Results obtained as a function of collision centrality and average pair transverse momentum ($k_T$) will be presented for the full range of the Au+Au beam energy scan ($\sqrt{s_{NN}} = 7.7 - 200$~GeV).