Higgs Hunters Talk

Fewer OCVs in the new data?

  • davidbundy77 by davidbundy77

    Maybe it's just my imagination, but it seems like the new data (since 21. January 2015) typically contain fewer OCVs than the previous data. Events with lots (5+) of tracks from a vertex seem to be especially rare. I doubt whether anybody has been counting, so it is hard to be objective, but I'd be interested in hearing what other people think who have been doing this for a while.

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  • ElisabethB by ElisabethB moderator

    Looks like that to me as well : less ocv's especially the ones with 5+ tracks. Weird.

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  • davidbundy77 by davidbundy77

    There also seem to be more events with only one muon. Maybe the criteria for inclusion in this new data set have been relaxed?

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  • ElisabethB by ElisabethB moderator

    Yep, for me as well. A lot of missing muons !

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  • andy.haas by andy.haas scientist

    The new data is from later in 2012, when the luminosity of the colliding proton beams (number of colliding protons in each event) was larger - about twice as big. So I would expect some differences! There will be more low-quality muons, that would pass the selections to make it into the data you see here, but not good enough to be drawn as muons by the display. (For instance, they could be missing a matching track in the tracker.) I'm not sure there should be fewer ocv's though - that may be because you are used to seeing simulations now!

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  • davidbundy77 by davidbundy77

    I agree that it is likely that our expectations have been distorted by the weeks of simulations, so that is the most likely explanation.

    Another possibility is that the lower-quality (slower?) muons mean that more lower-energy events are making the cut and are diluting the proportion of events with OCVs.

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  • LHCByloved by LHCByloved

    As far as I can say (was one who was so eager and ran out of data before new data set came up 😃), I also noticed differences with the ocv's in the new data (similar quota of ocv overall, but with less tracks) but I am also noticing that there are much more events with bottom quark decays (shown by blue marking in muon detector) than in the first data set.

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  • davidbundy77 by davidbundy77

    Now that the simulations are marked in Talk objects, it is clear that many of the OCVs with lots of tracks that we saw before were in fact simuations. Genuine OCVs with large numbers of tracks seem to be very rare, see this discussion http://talk.higgshunters.org/#/boards/BHH0000003/discussions/DHH00003pi but apparently that was expected all along.

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