[PWGEM/PhotonMeson] update 2PC (#12512)

Author: dsekihat

PWGEM/PhotonMeson/Core/DiphotonHadronMPC.h

@@ -371,7 +371,7 @@ struct DiphotonHadronMPC {
     fRegistry.addClone("DiphotonHadron/same/", "DiphotonHadron/mix/");
 
     // hadron-hadron
-    const AxisSpec axis_deta_hh{ConfDEtaBins, "#Delta#eta = #eta_{h}^{ref1} - #eta_{h}^{ref2}"};
+    const AxisSpec axis_deta_hh{60, -3, +3, "#Delta#eta = #eta_{h}^{ref1} - #eta_{h}^{ref2}"};
     const AxisSpec axis_dphi_hh{cfgNbinsDPhi, -M_PI / 2, +3 * M_PI / 2, "#Delta#varphi = #varphi_{h}^{ref1} - #varphi_{h}^{ref2} (rad.)"};
     // const AxisSpec axis_cosndphi_hh{cfgNbinsCosNDPhi, -1, +1, std::format("cos({0:d}(#varphi_{{h}}^{{ref1}} - #varphi_{{h}}^{{ref2}}))", cfgNmod.value)};
     fRegistry.add("HadronHadron/same/hDEtaDPhi", "hadron-hadron 2PC", kTH2D, {axis_dphi_hh, axis_deta_hh}, true);