Higgs Hunters Talk

Criteria to sort out non-OCV events?

  • ascil by ascil

    is there a way for me to at least sort out a part of the intersections that are not related to OCVs
    (for example crossing just because of the projection to a 2D image)?
    Now i did some pictures, I am thinking of three scenarios:

    1) given the preservaiton of charge is it possible that in an event creating two lines 
             in an OC-intersection, both lines are bending in the same direction? 
             Unfortunately, i am not good enough in imagining all possible
             directions to verify. And maybe, the event indeed involves more than two particles,
              and the remaining have been cut out by the algorithm?
    2) is it possible that in an event creating two lines both lines are moving to the right 
               with respect to the line connecting the center with the intersection? 
               I would expect one track to the left and one to the right, at most one line 
               proceeding (if the particle is heavy). 
     3) is there a maximum angle you would expect for the lines belonging to an OCV? 
               In the examples I saw that an angle of 45 degrees is still ok, but I had intersections 
               with more than 100 degrees. That would seem too much for me, 
               as i would expect the neutral particle that is not expected
               to be fast and so all decay products moving roughly into one direction.

    Maybe the answer is 'do not bother, the other views will make up for it'?

    Sorry if these questions have already been answered:
    I looked about the discussion, but did not read all answers in details.


  • peterwatkins by peterwatkins scientist

    Thanks for the very good questions.

    1 Not all the charged particle tracks are displayed in these pictures. For example the tracks with low energy are not shown.
    This means that charge conservation, where a neutral particle must decay into the same number of positive and negative charged tracks, will not always appear like this on the picture.

    2 Some of the momentum from the decay will usually be taken by neutral particles which dont leave tracks so the lines due the charged decay particles can be on the same side of the line you mention.

    3 The maximum angle of a track from the decay depends on the mass of the decaying particle and its momentum. As the mass and momentum are not known we cannot specify a maximum angle.

    Hope this helps