CA: update of the tracker input QA for STS

An update of the CA tracker input QA task for the STS detector.

core/data/CbmPixelHit.h

@@ -38,7 +38,7 @@ public:
 	 * \param[in] dx X position error of the hit [cm].
 	 * \param[in] dy Y position error of the hit [cm].
 	 * \param[in] dz Z position error of the hit [cm].
-	 * \param[in] dxy XY correlation of the hit.
+	 * \param[in] dxy X-Y covariance of the hit [cm**2].
 	 * \param[in] refId Some reference ID.
          * \param[in] time Hit time [ns].   
          * \param[in] timeError Error of hit time [ns].         
@@ -51,7 +51,7 @@ public:
 	 * \param address Detector unique identifier.
 	 * \param pos Position of the hit as TVector3 [cm].
 	 * \param err Position errors of the hit as TVector3 [cm].
-	 * \param dxy XY correlation of the hit.
+	 * \param dxy X-Y covariance of the hit [cm**2].
 	 * \param refId Some reference ID.
          * \param[in] time Hit time [ns].   
          * \param[in] timeError Error of hit time [ns].         
@@ -110,7 +110,7 @@ public:
 private:
   double fX, fY;    ///< X, Y positions of hit [cm]
   double fDx, fDy;  ///< X, Y errors [cm]
-  double fDxy;      ///< XY correlation
+  double fDxy;      ///< X-Y covariance of the hit [cm**2]
 
   ClassDef(CbmPixelHit, 1);
 };