update sigmaX and sigmaY to use LPC-like calculation in BetaFunc case

cms-sw · Nov 1, 2023 · c7f6425 · c7f6425
1 parent b9a4b4c
commit c7f6425
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Showing 4 changed files with 36 additions and 6 deletions.
diff --git a/CondFormats/BeamSpotObjects/interface/SimBeamSpotObjects.h b/CondFormats/BeamSpotObjects/interface/SimBeamSpotObjects.h
@@ -35,8 +35,8 @@ class SimBeamSpotObjects {
     fMeanX = 0.0;
     fMeanY = 0.0;
     fMeanZ = 0.0;
-    fSigmaX = 0.0;
-    fSigmaY = 0.0;
+    fSigmaX = -1.0;
+    fSigmaY = -1.0;
     fSigmaZ = 0.0;
     fbetastar = 0.0;
     femittance = 0.0;
@@ -76,8 +76,8 @@ class SimBeamSpotObjects {
   double meanY() const { return fMeanY; }
   double meanZ() const { return fMeanZ; }
   /// get sigmaX, sigmaY, sigmaZ
-  double sigmaX() const { return fSigmaX; }
-  double sigmaY() const { return fSigmaY; }
+  double sigmaX() const;
+  double sigmaY() const;
   double sigmaZ() const { return fSigmaZ; }
   /// get BetaStar and Emittance
   double betaStar() const { return fbetastar; }

diff --git a/CondFormats/BeamSpotObjects/src/SimBeamSpotObjects.cc b/CondFormats/BeamSpotObjects/src/SimBeamSpotObjects.cc
@@ -1,7 +1,26 @@
 #include "CondFormats/BeamSpotObjects/interface/SimBeamSpotObjects.h"
 
+#include <cmath>
 #include <iostream>
 
+// Get SigmaX and SigmaY:
+// - directly fSigmaX if >= 0 (in case of Gaussian Smearing)
+// - else from LPC-like calculation (in case of BetaFunc Smearing)
+double SimBeamSpotObjects::sigmaX() const {
+  if (fSigmaX >= 0.)  // Gaussian smearing
+    return fSigmaX;
+  else  // BetaFunc smearing
+    return (1 / std::sqrt(2)) * std::sqrt(femittance * fbetastar);
+}
+
+double SimBeamSpotObjects::sigmaY() const {
+  if (fSigmaY >= 0.)  // Gaussian smearing
+    return fSigmaY;
+  else  // BetaFunc smearing
+    return (1 / std::sqrt(2)) * std::sqrt(femittance * fbetastar);
+}
+
+// Printout SimBeamSpotObjects
 void SimBeamSpotObjects::print(std::stringstream& ss) const {
   ss << "-----------------------------------------------------\n"
      << "              Sim Beam Spot Data\n\n"

diff --git a/CondTools/BeamSpot/plugins/BeamProfile2DBWriter.cc b/CondTools/BeamSpot/plugins/BeamProfile2DBWriter.cc
@@ -99,8 +99,8 @@ void BeamProfile2DBWriter::fillDescriptions(edm::ConfigurationDescriptions& desc
   desc.add<double>("MeanX", 0.0)->setComment("in cm");
   desc.add<double>("MeanY", 0.0)->setComment("in cm");
   desc.add<double>("MeanZ", 0.0)->setComment("in cm");
-  desc.add<double>("SigmaX", 0.0)->setComment("in cm");
-  desc.add<double>("SigmaY", 0.0)->setComment("in cm");
+  desc.add<double>("SigmaX", -1.0)->setComment("in cm");
+  desc.add<double>("SigmaY", -1.0)->setComment("in cm");
   desc.add<double>("SigmaZ", 0.0)->setComment("in cm");
   desc.add<double>("BetaStar", 0.0)->setComment("in cm");
   desc.add<double>("Emittance", 0.0)->setComment("in cm");

diff --git a/CondTools/BeamSpot/test/BeamProfile2DBWriter_cfg.py b/CondTools/BeamSpot/test/BeamProfile2DBWriter_cfg.py
@@ -42,11 +42,22 @@
 process.maxEvents = cms.untracked.PSet(input = cms.untracked.int32(1))
 
 from CondTools.BeamSpot.beamProfile2DBWriter_cfi import beamProfile2DBWriter
+# For the BetaFunc smearing (realistic Beamspot) set the following parameters:
+# - X0, Y0, Z0, SigmaZ, BetaStar, Emittance
 process.BeamProfile2DBWriter = beamProfile2DBWriter.clone(X0        = 0.0458532,
                                                           Y0        = -0.016966,
                                                           Z0        = -0.074992,
                                                           SigmaZ    = 3.6,
                                                           BetaStar  = 30.0,
                                                           Emittance = 3.931e-8,)
 
+# For the Gaussian smearing (ideal Beamspot) set the following parameters:
+# - MeanX, MeanY, MeanZ, SigmaX, SigmaY, SigmaZ
+#process.BeamProfile2DBWriter = beamProfile2DBWriter.clone(MeanX     = 0.0,
+#                                                          MeanY     = 0.0,
+#                                                          MeanZ     = 0.0,
+#                                                          SigmaX    = 0.0015,
+#                                                          SigmaY    = 0.0015,
+#                                                          SigmaZ    = 3.6,)
+
 process.p = cms.Path(process.BeamProfile2DBWriter)