Update PbPb Angantyr settings

Author: romainschotter

MC/config/common/pythia8/generator/pythia8_PbPb_rescattering_536.cfg

@@ -7,10 +7,12 @@ Beams:frameType = 1
 ParticleDecays:limitTau0 = on
 ParticleDecays:tau0Max = 10.      ### match alice: 1cm/c = 10.0mm/c
 
-### Save some CPU at init of jobs
-### To avoid refitting, add the following lines to your configuration file:
-HeavyIon:SigFitNGen = 0
-HeavyIon:SigFitDefPar = 2.15,18.42,0.33
+### Initialize the Angantyr model to fit the total and semi-includive
+### cross sections in Pythia within some tolerance.
+HeavyIon:SigFitErr = 0.02,0.02,0.1,0.05,0.05,0.0,0.1,0.0
+
+### These parameters are typicall suitable for sqrt(S_NN)=5TeV
+HeavyIon:SigFitDefPar = 17.24,2.15,0.33,0.0,0.0,0.0,0.0,0.0
 
 ### enable hadronic rescattering
 HadronLevel:Rescatter = on # default = off