Update HiggsMakeDecay_tool.cc

jberger7 · web-flow · commit 2ff1bf60f144 · 2026-01-07T10:45:23.000-05:00
Simplified the form factor calculation (with some speed improvement)
diff --git a/sbncode/EventGenerator/MeVPrtl/Tools/Higgs/HiggsMakeDecay_tool.cc b/sbncode/EventGenerator/MeVPrtl/Tools/Higgs/HiggsMakeDecay_tool.cc
@@ -138,7 +138,7 @@ double PionPartialWidth(double pion_mass, double higs_mass, double mixing, bool
     // New, improved form factor based on the plot in arXiv:1909.11670v4
     // This form factor is significnatly different than in older versions
     // The expression is a fit to the Fig. 1 left panel in arXiv:1909.11670v4
-    form_factor = pow(0.289 * pow(higs_mass - 2 * Constants::Instance().pizero_mass,1.5),0.5);
+    form_factor = 0.537569 * pow(higs_mass - 2 * Constants::Instance().pizero_mass,0.75);
   }
   else {
     // Old form factor

Original file line number	Diff line number	Diff line change
`@@ -138,7 +138,7 @@ double PionPartialWidth(double pion_mass, double higs_mass, double mixing, bool`
`138`	`138`	`// New, improved form factor based on the plot in arXiv:1909.11670v4`
`139`	`139`	`// This form factor is significnatly different than in older versions`
`140`	`140`	`// The expression is a fit to the Fig. 1 left panel in arXiv:1909.11670v4`
`141`		`- form_factor = pow(0.289 * pow(higs_mass - 2 * Constants::Instance().pizero_mass,1.5),0.5);`
	`141`	`+ form_factor = 0.537569 * pow(higs_mass - 2 * Constants::Instance().pizero_mass,0.75);`
`142`	`142`	`}`
`143`	`143`	`else {`
`144`	`144`	`// Old form factor`