Candidate Veto

Before the candidate is evaluated further it has to pass a number of veto conditions to prevent excessive, unnecessary calculations:

1. Candidate already calculated

   The muon finder algorithm is made such that it is unavoidable that certain combinations of condensates are found several times. In this case a new candidate is vetoed to avoid duplication.

2. Candidate has too many cells

   The muon finder rejects candidates with too many cells in order to avoid unnecessary calculations.

3. Candidate hit ratio is too low

   Candidates with hit ratio less than are rejected. The hit ratio is a measure for the shape of the candidate, a bad hit ratio suggests that it does not stem from a traversing particle.

4. Candidate occupancy is too low

   Candidates with occupancy less than (occupancy is the ratio of number of candidate cells hit by the trajectory over the total number of calorimeter cells hit by the trajectory) are rejected. This cut is not executed for candidates which have a long and narrow shape or which are parallel to the beam axis but far away from it and for which the velocity is near the speed of light.

5. Not all condensates hit by trajectory

   Candidates for which not all condensates are hit by the fitted trajectory are rejected if the distance of the condensates which are not hit to the trajectory is smaller than .

6. Event without candidate still passes trigger

   MUFFIN tests whether the event, if the candidate cells were removed, would still pass the trigger condition. For a charged current event sample it would test whether the of the event is below the trigger cut of after the cells are removed. The candidate is rejected if the event still passes the trigger.

   This test is not performed if MUFFIN has found the event likely to be a multiple muon shower: MUFFIN calls an event a muon shower candidate if one or more of the following conditions is true:

   • There are parallel trajectories fitted to long and narrow condensates.
   • There are parallel muon chamber tracks.
   • There are more than parallel two dimensional muon chamber tracks.

A candidate that fails any of the veto conditions is removed and will not appear on the output. (the NTUPLE).