lcsim/src/org/lcsim/fit/helicaltrack

diff -u -r1.16 -r1.17
--- HelixUtils.java	18 Oct 2012 18:23:13 -0000	1.16
+++ HelixUtils.java	12 Jul 2013 23:04:17 -0000	1.17
@@ -7,15 +7,13 @@

 
 package org.lcsim.fit.helicaltrack;
 

-import hep.physics.vec.BasicHep3Vector;
-import hep.physics.vec.Hep3Vector;

 import hep.physics.matrix.BasicMatrix;
 import hep.physics.matrix.Matrix;

-

 import hep.physics.matrix.SymmetricMatrix;

+import hep.physics.vec.BasicHep3Vector;
+import hep.physics.vec.Hep3Vector;

 import java.util.ArrayList;
 import java.util.List;

-

 import org.lcsim.fit.circle.CircleFit;
 
 /**

@@ -70,7 +68,7 @@

         return PathCalc(xc(cfit), yc(cfit), RC(cfit), x0(cfit), y0(cfit), pos.x(), pos.y());
     }
     

-    /**

+     /**

      * Return the x-y path length from the DCA to a HelicalTrackHit.
      * @param helix HelicalTrackFit to be used in calculating the path length
      * @param hit hit to be used for the path length calculation

@@ -533,19 +531,25 @@

     }
     
     private static double xc(CircleFit cfit) {

-        return cfit.xref() + (RC(cfit) - cfit.dca()) * Math.sin(cfit.phi());

+        //Note that DCA for circle fit has opposite sign w.r.t. the standard L3 definition
+        return cfit.xref() + (RC(cfit) - (-1*cfit.dca())) * Math.sin(cfit.phi());
+        

     }
     
     private static double yc(CircleFit cfit) {

-        return cfit.yref() - (RC(cfit) - cfit.dca()) * Math.cos(cfit.phi());

+        //Note that DCA for circle fit has opposite sign w.r.t. the standard L3 definition
+        return cfit.yref() - (RC(cfit) - (-1*cfit.dca())) * Math.cos(cfit.phi());
+        

     }
     
     private static double x0(CircleFit cfit) {

-        return cfit.xref() - cfit.dca() * Math.sin(cfit.phi());

+        //Note that DCA for circle fit has opposite sign w.r.t. the standard L3 definition
+        return cfit.xref() - (-1*cfit.dca()) * Math.sin(cfit.phi());

     }
     
     private static double y0(CircleFit cfit) {

-        return cfit.yref() + cfit.dca() * Math.cos(cfit.phi());

+        //Note that DCA for circle fit has opposite sign w.r.t. the standard L3 definition
+        return cfit.yref() + (-1*cfit.dca()) * Math.cos(cfit.phi());

     }
 
 }

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