Title: Pion Femtoscopic Correlations in Au+Au Collisions at √s_NN = 3.2, 3.5, and 3.9 GeV in the STAR Experiment at RHIC
PAs: Vinh Luong, Youquan Qi, Anna Kraeva, Grigory Nigmatkulov, Xiaofeng Luo
Target journal: Physical Review C
Presentations in CF PWG:
1. First results: Sep 13 '22
2. Track splitting and track merging: Dec 1 '22
3. Octant cut for track merging suppression: Jun 1 '23
4. Systematic uncertainty: two-track effects, momentum resolution, fitting range, Coulomb correction: Jul 27 '23
5. Purity correction: Oct 17 '23
6. Paper proposal to CF PWG: 
Preliminary results: presentation, figures

Abstract

Figures for the paper

Figure 1. (a) Ionization loss measured by TPC and (b) inverse velocity measured by TOF as a function of rigidity of primary tracks in Au+Au collisions at √s_NN = 3.2 GeV. Color regions denote π⁺ and π^– selected for the analysis.


Figure 2. Transverse momentum versus rapidity acceptance of single π^– (left column) and pair of π^–π^– (right column) in the center-of-mass frame of Au+Au collisions at √s_NN = 3.2, 3.5, and 3.9 GeV. Dashed rectangles denote selected windows for the rapidty-differential analysis.

Figure 3. Top row: Projections of the correlation functions in the LCMS frame onto the qout, qside, and qlong axes for π⁺π⁺ (circles) and π^–π^– (triangles) pairs for mid rapidity pions with 0.15 < k_T < 0.25 GeV/c from 0–10% central Au+Au collisions at √s_NN = 3.2 GeV. The curves show the projections of the 3-dimensional fit to the correlation functions. Bottom row: The ratio of the correlation functions between π⁺π⁺ and π^–π^– pairs. Errors are statistical only.

Figure 4. Pair transverse momentum dependence of λ, R_out, R_side, R_long, R²_out-long of midrapidity pions for 0–10%, 10–30%, 30–50%, and 50–80% centrality classes from Au+Au collisions at √s_NN = 3.2, 3.5, and 3.9 GeV. The closed markers are for π^–π^– and the open markers for π⁺π⁺ pairs. The systematic uncertainties are shown by boxes. The statistical uncertainties are smaller than the marker size.

Figure 5. Collision energy dependence of λ, R_out, R_side, R_long of midrapidity pions and〈k_T〉≈ 0.2 GeV/c in Au+Au, Pb+Pb, and Pb+Au central collisions. Errors on NA49 and CERES points include systematic errors. Errors on HADES, STAR COL and STAR FXT points are systematical, their statistical errors are smaller than the marker size.

Figure 6. Collision energy dependence of R²_out – R²_side of midrapidity pions and 〈m_T〉≈ 0.32 GeV/c in Au+Au, Pb+Pb, and Pb+Au central collisions. Errors on other results are statistical only. Errors on this work are systematical, the statistical errors are smaller than the marker size.

Figure 7. Pair rapidity dependence in center-of-mass frame of λ, R_out, R_side, R_long, R²_out-long for 0–10%, 10–30%, 30–50%, and 50–80% centrality classes from Au+Au collisions at √s_NN = 3.2, 3.5, and 3.9 GeV. The closed markers are for π^–π^– and the open markers for π⁺π⁺ pairs. Gray markers are mirrored data points w.r.t. midrapidity. The systematic uncertainties are shown by boxes. The statistical uncertainties are smaller than the marker size.

Conclusion

Analysis Note
(TBA)