From 7a6351bffc9c0bc4507688788c6c7c12fd51bac9 Mon Sep 17 00:00:00 2001
From: francescobrivio <francesco.brivio@cern.ch>
Date: Fri, 17 Feb 2023 11:55:17 +0100
Subject: [PATCH] Adding a check on the BS transverse widths in
 OnlineBeamSpotESProducer

---
 .../plugins/OnlineBeamSpotESProducer.cc       | 35 +++++++++++++------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/RecoVertex/BeamSpotProducer/plugins/OnlineBeamSpotESProducer.cc b/RecoVertex/BeamSpotProducer/plugins/OnlineBeamSpotESProducer.cc
index a69e8aaf12bf4..efda9e22daa7c 100644
--- a/RecoVertex/BeamSpotProducer/plugins/OnlineBeamSpotESProducer.cc
+++ b/RecoVertex/BeamSpotProducer/plugins/OnlineBeamSpotESProducer.cc
@@ -30,6 +30,7 @@ class OnlineBeamSpotESProducer : public edm::ESProducer {
 private:
   const BeamSpotOnlineObjects* compareBS(const BeamSpotOnlineObjects* bs1, const BeamSpotOnlineObjects* bs2);
   const BeamSpotOnlineObjects* checkSingleBS(const BeamSpotOnlineObjects* bs1);
+  bool isGoodBS(const BeamSpotOnlineObjects* bs1) const;
 
   edm::ESGetToken<BeamSpotObjects, BeamSpotTransientObjectsRcd> const bsToken_;
   edm::ESGetToken<BeamSpotOnlineObjects, BeamSpotOnlineHLTObjectsRcd> bsHLTToken_;
@@ -38,12 +39,14 @@ class OnlineBeamSpotESProducer : public edm::ESProducer {
   BeamSpotObjects fakeBS_;
   const int timeThreshold_;
   const double sigmaZThreshold_;
+  const double sigmaXYThreshold_;
 };
 
 OnlineBeamSpotESProducer::OnlineBeamSpotESProducer(const edm::ParameterSet& p)
     // get parameters
     : timeThreshold_(p.getParameter<int>("timeThreshold")),
-      sigmaZThreshold_(p.getParameter<double>("sigmaZThreshold")) {
+      sigmaZThreshold_(p.getParameter<double>("sigmaZThreshold")),
+      sigmaXYThreshold_(p.getParameter<double>("sigmaXYThreshold") * 1E-4) {
   auto cc = setWhatProduced(this);
 
   fakeBS_.setBeamWidthX(0.1);
@@ -60,6 +63,7 @@ void OnlineBeamSpotESProducer::fillDescriptions(edm::ConfigurationDescriptions&
   edm::ParameterSetDescription dsc;
   dsc.add<int>("timeThreshold", 48)->setComment("hours");
   dsc.add<double>("sigmaZThreshold", 2.)->setComment("cm");
+  dsc.add<double>("sigmaXYThreshold", 4.)->setComment("um");
   desc.addWithDefaultLabel(dsc);
 }
 
@@ -80,15 +84,15 @@ const BeamSpotOnlineObjects* OnlineBeamSpotESProducer::compareBS(const BeamSpotO
 
   // Logic to choose between the two BeamSpots:
   // 1. If both BS are older than limitTime retun fake BS
-  // 2. If only one BS is newer than limitTime return it only if it has
-  //    sigmaZ larger than sigmaZthreshold_ and the fit converged (BeamType 2)
-  // 3. If both are newer than the limit threshold return
-  //    the BS that converged and has larger sigmaZ
+  // 2. If only one BS is newer than limitTime return it only if
+  //     it passes isGoodBS (checks on sigmaZ, sigmaXY and fit convergence)
+  // 3. If both are newer than the limit threshold return the BS that
+  //     passes isGoodBS and has larger sigmaZ
   if (diffBStime1 > limitTime && diffBStime2 > limitTime) {
     edm::LogInfo("OnlineBeamSpotESProducer") << "Defaulting to fake because both payloads are too old.";
     return nullptr;
   } else if (diffBStime2 > limitTime) {
-    if (bs1->sigmaZ() > sigmaZThreshold_ && bs1->beamType() == 2) {
+    if (isGoodBS(bs1)) {
       return bs1;
     } else {
       edm::LogInfo("OnlineBeamSpotESProducer")
@@ -96,7 +100,7 @@ const BeamSpotOnlineObjects* OnlineBeamSpotESProducer::compareBS(const BeamSpotO
       return nullptr;
     }
   } else if (diffBStime1 > limitTime) {
-    if (bs2->sigmaZ() > sigmaZThreshold_ && bs2->beamType() == 2) {
+    if (isGoodBS(bs2)) {
       return bs2;
     } else {
       edm::LogInfo("OnlineBeamSpotESProducer")
@@ -104,13 +108,13 @@ const BeamSpotOnlineObjects* OnlineBeamSpotESProducer::compareBS(const BeamSpotO
       return nullptr;
     }
   } else {
-    if (bs1->sigmaZ() > bs2->sigmaZ() && bs1->beamType() == 2) {
+    if (bs1->sigmaZ() > bs2->sigmaZ() && isGoodBS(bs1)) {
       return bs1;
-    } else if (bs2->sigmaZ() >= bs1->sigmaZ() && bs2->beamType() == 2) {
+    } else if (bs2->sigmaZ() >= bs1->sigmaZ() && isGoodBS(bs2)) {
       return bs2;
     } else {
       edm::LogInfo("OnlineBeamSpotESProducer")
-          << "Defaulting to fake because despite both payloads are young enough, none has the right BeamType.";
+          << "Defaulting to fake because despite both payloads are young enough, none has passed the fit sanity checks";
       return nullptr;
     }
   }
@@ -129,13 +133,22 @@ const BeamSpotOnlineObjects* OnlineBeamSpotESProducer::checkSingleBS(const BeamS
   auto limitTime = std::chrono::microseconds((std::chrono::hours)timeThreshold_).count();
 
   // Check that the BS is within the timeThreshold, converges and passes the sigmaZthreshold
-  if (diffBStime1 < limitTime && bs1->sigmaZ() > sigmaZThreshold_ && bs1->beamType() == 2) {
+  if (diffBStime1 < limitTime && isGoodBS(bs1)) {
     return bs1;
   } else {
     return nullptr;
   }
 }
 
+// This method is used to check the quality of the beamspot fit
+bool OnlineBeamSpotESProducer::isGoodBS(const BeamSpotOnlineObjects* bs1) const {
+  if (bs1->sigmaZ() > sigmaZThreshold_ && bs1->beamType() == reco::BeamSpot::Tracker &&
+      bs1->beamWidthX() > sigmaXYThreshold_ && bs1->beamWidthY() > sigmaXYThreshold_)
+    return true;
+  else
+    return false;
+}
+
 std::shared_ptr<const BeamSpotObjects> OnlineBeamSpotESProducer::produce(const BeamSpotTransientObjectsRcd& iRecord) {
   auto legacyRec = iRecord.tryToGetRecord<BeamSpotOnlineLegacyObjectsRcd>();
   auto hltRec = iRecord.tryToGetRecord<BeamSpotOnlineHLTObjectsRcd>();