"Figure 10" of "Centrality dependence of low-momentum direct-photon production in Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV"
メタデータ
- 公開日
- 2023-01-01
- DOI
-
- 10.17182/hepdata.142985.v1/t6
- 公開者
- HEPData
- データ作成者 (e-Rad)
-
- PHENIX Collaboration
説明
The PHENIX experiment at RHIC has measured the centrality dependence of the direct photon yield from Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV down to $p_T$ = 0.4 GeV/$c$. Photons are detected via photon conversions to $e^+e^−$ pairs and an improved technique is applied that minimizes the systematic uncertainties that usually limit direct photon measurements, in particular at low $p_T$. We find an excess of direct photons above the $N_{coll}$-scaled yield measured in $p$+$p$ collisions. This excess yield is well described by an exponential distribution with an inverse slope of about 240 MeV/$c$ in the $p_T$ range from 0.6 - 2.0 GeV/$c$. While the shape of the $p_T$ distribution is independent of centrality within the experimental uncertainties, the yield increases rapidly with increasing centrality, scaling approximately with $N_{part}^{\alpha}$, where $\alpha$ = 1.38 $\pm$ 0.03(stat) $\pm$ 0.07(syst).
Integrated thermal photon yields as a function of $N_{part}$ for different lower $p_T$ integration limits.
