Please consider the following formatting changes to #15915

Detectors/GlobalTracking/include/GlobalTracking/MatchCosmics.h

@@ -41,7 +41,8 @@ class VDriftCorrFact;
 namespace gpu
 {
 class TPCFastTransformPOD;
-}
+class GPUO2InterfaceRefit;
+} // namespace gpu
 namespace globaltracking
 {
 
@@ -82,7 +83,20 @@ class MatchCosmics
     float chi2 = -1.f;   ///< matching chi2
     int next = MinusOne; ///< index of eventual next record
     float tCommon = 0.f; ///< common time [mus] fixed by z continuity of TPC-only legs on opposite TPC sides
-    float tCommonErr = -1.f; ///< its 1 sigma error [mus]; < 0: not fixed, the refit uses the centre of the time-bracket overlap and the cosmic's time error is the overlap's half-width
+    float tCommonErr = -1.f;      ///< its 1 sigma error [mus]; < 0: not fixed, the refit uses the centre of the time-bracket overlap and the cosmic's time error is the overlap's half-width
+    float tofScore = -1.f;        ///< score of the top / bottom TOF hit pair matching the muon's flight (tofFlightSelection; < 0: none); a pair with one wins against pairs without
+    float tCommonNoTOF = 0.f;     ///< tCommon before a TOF flight pair replaced it: the refit falls back to it if the refit at the TOF time fails
+    float tCommonErrNoTOF = -1.f; ///< tCommonErr before a TOF flight pair replaced it
+  };
+
+  struct TOFCandidate { ///< TOF cluster along the outward continuation of a TPC-only seed
+    int index = -1;     ///< index of the TOF cluster
+    double timeNS = 0.; ///< its time since the start of the TF [ns]
+    float dy = 0.f;     ///< cluster - predicted y in the frame of the cluster's sector [cm]
+    float dz = 0.f;     ///< cluster - predicted z, the leg's z taken at its own reference time tRef [cm]
+    float gx = 0.f;     ///< global position of the cluster [cm]
+    float gy = 0.f;
+    float gz = 0.f;
   };
 
   struct TrackSeed : public o2::track::TrackParCov {
@@ -137,7 +151,11 @@ class MatchCosmics
  private:
   void updateTimeDependentParams();
   RejFlag checkPair(int i, int j);
-  void registerMatch(int i, int j, float chi2, float tCommon = 0.f, float tCommonErr = -1.f);
+  bool refitSeedAtTime(const TrackSeed& seed, float timeMUS, TrackSeed& out);
+  void registerMatch(int i, int j, float chi2, float tCommon = 0.f, float tCommonErr = -1.f, float tofScore = -1.f, float tCommonNoTOF = 0.f, float tCommonErrNoTOF = -1.f);
+  void prepareTOFClusters(const o2::globaltracking::RecoContainer& data);
+  const std::vector<TOFCandidate>& getTOFCandidates(int iseed);
+  float findTOFFlightPair(int i, int j, float tMinMUS, float tMaxMUS, float& tofTimeMUS);
   void suppressMatch(int partner0, int partner1);
   void createSeeds(const o2::globaltracking::RecoContainer& data);
   bool validateMatch(int partner0);
@@ -164,6 +182,15 @@ class MatchCosmics
   float mQ2PtCutoff = 1e9;
   float mQ2PtCutoffOppositeSides = 1e9;
   const MatchCosmicsParams* mMatchParams = nullptr;
+  const o2::globaltracking::RecoContainer* mRecoData = nullptr; ///< inputs of the TF being processed
+  o2::gpu::GPUO2InterfaceRefit* mTPCRefitter = nullptr;         ///< TPC refitter of the TF being processed (owned by process())
+  size_t mNRefitsCommonTime = 0;                                ///< seeds refitted at the common time of a same-side pair in this TF
+  std::vector<int> mTOFClusterOrder;                            ///< TOF clusters of the TF sorted in time (tofFlightSelection)
+  std::vector<float> mTOFClusterTimeMUS;                        ///< their times since the start of the TF [mus], same order
+  std::vector<std::vector<TOFCandidate>> mSeedTOFCandidates;    ///< TOF candidates per seed, filled on first use
+  std::vector<bool> mSeedTOFDone;                               ///< the TOF candidates of the seed are filled
+  size_t mNTOFConfirmed = 0;                                    ///< accepted pairs with a TOF flight pair in this TF
+  size_t mNTOFFallbacks = 0;                                    ///< TOF-confirmed winners refitted at their time without TOF in this TF
 
   std::vector<o2d::TrackCosmics> mCosmicTracks;
   std::vector<o2::MCCompLabel> mCosmicTracksLbl;

Detectors/GlobalTracking/include/GlobalTracking/MatchCosmicsParams.h

@@ -38,9 +38,14 @@ struct MatchCosmicsParams : public o2::conf::ConfigurableParamHelper<MatchCosmic
   float minSeedPt = 0.10f;     // use only tracks above this pT (scaled with field)
   int minSeedNClTPC = 0;       // use only TPC-only seeds with at least this number of clusters (0: no cut)
   float minSeedDCAxy = 0.f;    // use only tracks with |DCA_xy| to the beam line >= this [cm] (0: no cut; rejects collision tracks in physics data)
-  float minSeedDCAxyNSigma = 0.f; // use only tracks with |DCA_xy| >= this * sigma(DCA_xy) (0: no cut; poorly measured collision tracks)
-  bool constrainTPCOnlyZ = false; // TPC-only legs: test z at a common time (same side, or a leg with known time), else require the time implied by z continuity in both brackets
-  bool vetoSameHalf = false;      // reject pairs whose two legs lie on the same side of the closest approach (two pieces of one leg)
+  float minSeedDCAxyNSigma = 0.f;         // use only tracks with |DCA_xy| >= this * sigma(DCA_xy) (0: no cut; poorly measured collision tracks)
+  bool constrainTPCOnlyZ = false;         // TPC-only legs: test z at a common time (same side, or a leg with known time), else require the time implied by z continuity in both brackets
+  bool vetoSameHalf = false;              // reject pairs whose two legs lie on the same side of the closest approach (two pieces of one leg)
+  bool refitSameSideAtCommonTime = false; // TPC-only legs on the same side: compare them refitted at the centre of their brackets' overlap instead of at their own time0s
+  bool tofFlightSelection = false;        // needs TOF clusters: accepted pairs of TPC-only legs pointing to a top / bottom TOF hit pair with the muon's flight time win the selection, refit at that time (if that fails, at their time without TOF)
+  float tofRoad = 5.f;                    // half-width [cm] in y and z of the road at the TOF around the outward continuation of a TPC-only leg
+  float tofFlightTolerance = 2.f;         // max. deviation [ns] of the top / bottom TOF time difference from the flight time along the helix
+  float tofTimeError = 0.1f;              // error [mus] of the TOF time of a confirmed cosmic, for its refit and time window (covers TPC vs TOF offsets)
   float nSigmaTError = 4.f;    // number of sigmas on track time error for matching (except for TPC which provides an interval)
   float tpcExtraZError2 = 1.f; // extra error^2 on the TPC-only track Z coordinate
   float fiducialRIP = 1.0f;    // consider track having |Y@x=0|< this as passing DCA cut (if requested)