Merge branch '122-add-constant-for-nucleon-mass' into 'master'

Resolve "add constant for nucleon mass"

Closes #122

See merge request !75

Framework/Particles/ParticleProperties.h

@@ -23,13 +23,12 @@
 #include <iosfwd>
 #include <type_traits>
 
-#include <corsika/units/PhysicalConstants.h>
 #include <corsika/units/PhysicalUnits.h>
 
 /**
  *
  * The properties of all elementary particles is stored here. The data
- * is taken from the Pythia ParticleData.xml file.
+ * are taken from the Pythia ParticleData.xml file.
  *
  */
 

Framework/Particles/testParticles.cc

@@ -34,6 +34,8 @@ TEST_CASE("ParticleProperties", "[Particles]") {
   SECTION("Masses") {
     REQUIRE(Electron::GetMass() / (511_keV) == Approx(1));
     REQUIRE(Electron::GetMass() / GetMass(Code::Electron) == Approx(1));
+    
+    REQUIRE((Proton::GetMass() + Neutron::GetMass()) / corsika::units::constants::nucleonMass == Approx(2));
   }
 
   SECTION("Charges") {

Framework/Units/PhysicalConstants.h

@@ -61,7 +61,9 @@ namespace corsika::units::constants {
 
   // unified atomic mass unit
   constexpr quantity<mass_d> u{Rep(1.6605402e-27L) * kilogram};
-
+  
+  auto constexpr nucleonMass = 0.5 * (0.93827 + 0.93957) * 1e9 * electronvolt;
+  
   // etc.
 
 } // namespace corsika::units::constants

Framework/Units/PhysicalUnits.h

@@ -18,28 +18,11 @@ namespace phys::units {
 /**
  * @file PhysicalUnits
  *
- * Add new units and types we need. Units are compile-time. We support
- * different system of units in parallel. Literals are used for
- * optimal coding style.
+ * Add new units and types we need. Units are compile-time. Literals are
+ * used for optimal coding style.
  *
  */
-/*
-namespace corsika::units::hep {
-  using namespace phys::units;
-  using namespace phys::units::literals;
-  using namespace phys::units::io;
-
-  /// defining HEP energy, mass, momentum
-  using energy_hep_d = phys::units::energy_d;
-  constexpr phys::units::quantity<energy_hep_d> GeV{corsika::units::constants::eV};
-  // corsika::units::constants::e / phys::units::coulomb * phys::units::joule };
-
-  using MassType = phys::units::quantity<energy_hep_d, double>;
-  using MomentumType = phys::units::quantity<energy_hep_d, double>;
-  using EnergyType = phys::units::quantity<energy_hep_d, double>;
 
-} // namespace corsika::units::hep
-*/
 namespace corsika::units::si {
   using namespace phys::units;
   using namespace phys::units::literals;