set THETA0_MIN to 1e-5

Based on some testing it seems that when fitting muons the likelihood ratio and
angular fits are better without a minimum theta0. I also determined during
testing that the minimum value would cause a discontinuity in the derivative of
the charge as a function of position which could cause the estimate of the
direct charge to be worse.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/path.h b/src/path.h
index a3eb712..7aa2fd5 100644
--- a/src/path.h
+++ b/src/path.h
@@ -27,8 +27,12 @@
  * By introducing a minimum value for the scattering RMS we broaden the angular
  * distribution such that it effectively averages across the face of a PMT.
  *
- * FIXME: Should do some tests to figure out what is the best value. */
-#define MIN_THETA0 0.01
+ * Initially had this at 0.01 since that roughly corresponded to the angular
+ * width of the PMT from the center to the PSUP. Now, since we calculate the
+ * angular width for every point in get_theta0_min() this isn't necessary. We
+ * still keep it though so that at the *very* beginning of the track theta0 is
+ * not zero. */
+#define MIN_THETA0 1e-5
 
 typedef double getKineticEnergyFunc(double x, void *params);