From 67dc071f0978642cfd2156a7dace21036fb4b860 Mon Sep 17 00:00:00 2001
From: Maximilian Reininghaus <maximilian.reininghaus@kit.edu>
Date: Fri, 12 Jun 2020 16:28:43 +0200
Subject: [PATCH] added further checks in testCOMboost
---
Framework/Utilities/testCOMBoost.cc | 65 ++++++++++++++++-------------
1 file changed, 37 insertions(+), 28 deletions(-)
diff --git a/Framework/Utilities/testCOMBoost.cc b/Framework/Utilities/testCOMBoost.cc
index 572839296..2f5c7c62f 100644
--- a/Framework/Utilities/testCOMBoost.cc
+++ b/Framework/Utilities/testCOMBoost.cc
@@ -35,6 +35,8 @@ auto const energy = [](HEPMassType m, Vector<hepmomentum_d> const& p) {
return sqrt(m * m + p.squaredNorm());
};
+auto const momentum = [](HEPEnergyType E, HEPMassType m) { return sqrt(E * E - m * m); };
+
// helper function for mandelstam-s
auto const s = [](HEPEnergyType E, QuantityVector<hepmomentum_d> const& p) {
return E * E - p.squaredNorm();
@@ -54,7 +56,7 @@ TEST_CASE("boosts") {
// define projectile kinematics in lab frame
HEPMassType const projectileMass = 1._GeV;
- Vector<hepmomentum_d> pProjectileLab{rootCS, {0_GeV, 1_PeV, 0_GeV}};
+ Vector<hepmomentum_d> pProjectileLab{rootCS, {0_GeV, 20_GeV, 0_GeV}};
HEPEnergyType const eProjectileLab = energy(projectileMass, pProjectileLab);
const FourVector PprojLab(eProjectileLab, pProjectileLab);
@@ -101,18 +103,26 @@ TEST_CASE("boosts") {
// define projectile kinematics in lab frame
HEPMassType const projectileMass = 1_GeV;
- Vector<hepmomentum_d> pProjectileLab{rootCS, {0_GeV, 0_PeV, -1_PeV}};
+ Vector<hepmomentum_d> pProjectileLab{rootCS, {0_GeV, 0_GeV, -20_GeV}};
HEPEnergyType const eProjectileLab = energy(projectileMass, pProjectileLab);
const FourVector PprojLab(eProjectileLab, pProjectileLab);
+ auto const sqrt_s_lab =
+ sqrt(s(eProjectileLab + targetMass, pProjectileLab.GetComponents(rootCS)));
+
// define boost to com frame
COMBoost boost(PprojLab, targetMass);
// boost projecticle
auto const PprojCoM = boost.toCoM(PprojLab);
+ auto const a = PprojCoM.GetSpaceLikeComponents().GetComponents(boost.GetRotatedCS());
+ CHECK(a.GetX() / 1_GeV == Approx(0));
+ CHECK(a.GetY() / 1_GeV == Approx(0));
+ CHECK(a.GetZ() / (momentum(sqrt_s_lab / 2, projectileMass)) == Approx(1));
// boost target
auto const PtargCoM = boost.toCoM(FourVector(targetMass, pTargetLab));
+ CHECK(PtargCoM.GetTimeLikeComponent() / sqrt_s_lab == Approx(.5));
// sum of momenta in CoM, should be 0
auto const sumPCoM =
@@ -183,31 +193,30 @@ TEST_CASE("boosts") {
PprojCoM.GetSpaceLikeComponents() + PtargCoM.GetSpaceLikeComponents();
CHECK(sumPCoM.norm() / P0 == Approx(0).margin(absMargin)); // MAKE RELATIVE CHECK
}
+}
- SECTION("rest frame") {
- HEPMassType const projectileMass = 1_GeV;
- HEPMomentumType const P0 = 1_TeV;
- Vector<hepmomentum_d> pProjectileLab{rootCS, {0_GeV, P0, 0_GeV}};
- HEPEnergyType const eProjectileLab = energy(projectileMass, pProjectileLab);
- const FourVector PprojLab(eProjectileLab, pProjectileLab);
-
- COMBoost boostRest(pProjectileLab, projectileMass);
- auto const& csPrime = boostRest.GetRotatedCS();
- FourVector const rest4Mom = boostRest.toCoM(PprojLab);
-
- CHECK(rest4Mom.GetTimeLikeComponent() / 1_GeV == Approx(projectileMass / 1_GeV));
- CHECK(rest4Mom.GetSpaceLikeComponents().norm() / 1_GeV ==
- Approx(0).margin(absMargin));
-
- FourVector const a{0_eV, Vector{csPrime, 0_eV, 5_GeV, 0_eV}};
- FourVector const b{0_eV, Vector{rootCS, 3_GeV, 0_eV, 0_eV}};
- auto const aLab = boostRest.fromCoM(a);
- auto const bLab = boostRest.fromCoM(b);
-
- CHECK(aLab.GetNorm() / a.GetNorm() == Approx(1));
- CHECK(aLab.GetSpaceLikeComponents().GetComponents(csPrime)[1].magnitude() ==
- Approx((5_GeV).magnitude()));
- CHECK(bLab.GetSpaceLikeComponents().GetComponents(rootCS)[0].magnitude() ==
- Approx((3_GeV).magnitude()));
- }
+TEST_CASE("rest frame") {
+ HEPMassType const projectileMass = 1_GeV;
+ HEPMomentumType const P0 = 1_TeV;
+ Vector<hepmomentum_d> pProjectileLab{rootCS, {0_GeV, P0, 0_GeV}};
+ HEPEnergyType const eProjectileLab = energy(projectileMass, pProjectileLab);
+ const FourVector PprojLab(eProjectileLab, pProjectileLab);
+
+ COMBoost boostRest(pProjectileLab, projectileMass);
+ auto const& csPrime = boostRest.GetRotatedCS();
+ FourVector const rest4Mom = boostRest.toCoM(PprojLab);
+
+ CHECK(rest4Mom.GetTimeLikeComponent() / 1_GeV == Approx(projectileMass / 1_GeV));
+ CHECK(rest4Mom.GetSpaceLikeComponents().norm() / 1_GeV == Approx(0).margin(absMargin));
+
+ FourVector const a{0_eV, Vector{csPrime, 0_eV, 5_GeV, 0_eV}};
+ FourVector const b{0_eV, Vector{rootCS, 3_GeV, 0_eV, 0_eV}};
+ auto const aLab = boostRest.fromCoM(a);
+ auto const bLab = boostRest.fromCoM(b);
+
+ CHECK(aLab.GetNorm() / a.GetNorm() == Approx(1));
+ CHECK(aLab.GetSpaceLikeComponents().GetComponents(csPrime)[1].magnitude() ==
+ Approx((5_GeV).magnitude()));
+ CHECK(bLab.GetSpaceLikeComponents().GetComponents(rootCS)[0].magnitude() ==
+ Approx((3_GeV).magnitude()));
}
--
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