1 files changed, 2 insertions, 0 deletions
diff --git a/src/pdg.h b/src/pdg.h
index ff62f7a..98046f5 100644
--- a/src/pdg.h
+++ b/src/pdg.h
@@ -4,7 +4,9 @@
 #define SPEED_OF_LIGHT 29.9792458 /* cm/ns */
 /* From http://pdg.lbl.gov/2017/AtomicNuclearProperties/HTML/water_liquid.html */
 #define RADIATION_LENGTH 36.08 /* g/cm^2 */
+#define ELECTRON_MASS 0.5109989461 /* MeV */
 #define MUON_MASS 105.6583745 /* MeV */
+#define PROTON_MASS 938.272081 /* MeV */
 #define FINE_STRUCTURE_CONSTANT 7.297352566417e-3
 
 double get_scattering_rms(double x, double p, double beta, double z, double rho);