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    Higgs at LHeC

    → Europe/Zurich
    CERN

    CERN
    Description
    CERN - Tokyo Tech - Liverpool - Johannesburg
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    Chen and Kechan joined the meeting.

    Satoshi showed the distributions of variables used in his
    'cut 0' in order to clarify the difference in event yields (6fb)
    compared to Chen et al.'s arXiv result (16fb).
    The electron reconstruction efficiency seems the biggest reason,
    which is only 50%.  It was suggested to see the truth level distributions.
    Uta commented the electron pT generator cut should be lowered.
    Also the effect of tracking acceptance (4 vs. 4.7) would be interesting to see.
    It was suggested to use the common selection as in CC, e.g. jet radius of 0.7.

    Masahiro (Tanaka) showed the Hbb result using 1ab-1, i.e. 10 years of LHeC.
    Polarization was set to -0.8, and 90% photoproduction veto was assumed
    using forward electron tagger.  As a result, coupling precision of 1% was shown.
    It was suggested to place the large amount of PHP MC he generated for
    common use, somewhere on CERN machine.

    Uta showed updates on Liverpool Hcc study compared to 2015 Chavanne talk where R=0.9 jets and ATLAS Run 1 vertex resolution was used, and 133 Hcc events could be selected based on a multivariate analysis (BDT).
    Studying various R values and vertex resolutions, it was found that R=0.5 jets and a vertex detector like ATLAS Run 2 (1/2 of the resolution as for Run1) gives a significantly improved S/N of 0.5 for Hcc events.
    All backgrounds as usual have been included, and the BDT training was redone using the same variables as shown in Chavannes 2015. Around 500
    Hcc events could be separated by BDT, implying a 5% measurement on the Hcc coupling assuming that all backgrounds are known to 2%.

    It was discussed if we may need other Higgs related backgrounds like Higgs-> glue glue for a publication. Best if we could have an inclusive Higgs sample containing all decays except the signal decay considered. This is currently not possible in MG5, and ideas are welcome.

    The study was optimised for Hcc (i.e. Hbb was considered a background) and using the Hcc optimisation, the Hbb coupling was found to be measured to 1% (assuming 90% PHP rejection but 100% backgrounds other wise). A further optimisation for Hbb as the signal may deliver even better results.

     

    There are minutes attached to this event. Show them.
      • 11:00 → 11:20
        Update on invisible decay study 20m
        Speaker: Satoshi Kawaguchi (Tokyo Institute of Technology (JP))
        May_9th.pdf
      • 11:20 → 11:40
        Status Report 20m
        Speaker: Masahiro Tanaka (Tokyo Institute of Technology (JP))
        2016_05_09.pdf
      • 11:40 → 12:00
        Status report 2 20m
        Speakers: Mukesh Kumar (KarMic), Mukesh Kumar (University of the Witwatersrand (ZA)), Xifeng Ruan (University of the Witwatersrand (ZA))
      • 12:00 → 12:20
        Hbb and Hcc using jet lifetime probabilities 20m
        Speaker: Uta Klein (University of Liverpool (GB))
        Hcc_09.05.2016.pdf
      • 12:20 → 12:40
        Status of Wits Studies 20m
        Speakers: Bruce Mellado Garcia (University of the Witwatersrand), Bruce Mellado Garcia (University of Wisconsin), Mukesh Kumar (University of the Witwatersrand (ZA)), Xifeng Ruan (University of the Witwatersrand (ZA))