Light Mass Higgs meeting 2

Europe/Zurich
60/6-015 - Room Georges Charpak (Room F) (CERN)

60/6-015 - Room Georges Charpak (Room F)

CERN

20
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Extensive discussion of coupling parameter definitions (initiated by talks from Marco & Michael)
- HDECAY has Hgamgam NLO treatment.
- use Prophecy4f instead of HDECAY for VV
- long misunderstanding between theory and experimental community on how couplings are fitted and what is meant by effective lagrangian. Cleared afterwards by email and reached some understanding: experimentalists don't do any (recalcualtions) of Higgs production or decay in the fits, but just scale event yields. The implications are still under discussion
- idea for NLO: stick to SM and add parametric BSM additions. SM is restored for all new parameters set to 0. Otherwise no way of just scaling individual couplings at NLO and stay finite
- for the time being LO definitions of couplings are the best we have. Everybody is invited to submit ideas on new definitions for coupling parameters! The interface between the theory and experimental community should be a set of function that calculate sigma*BR for each Higgs channels as function of the coupling parameters
- otherwise agreed on general approach as summarized in: https://twiki.cern.ch/twiki/bin/view/LHCPhysics/HiggsLightMass

Higgs Spin/CP:
- Markus gave an overview of the available channels (focused on low lumi possibilities) and available codes
- Jessica presented an effective Spin-2 model for the H-vector boson coupling implemented in VBFNLO
- people from VBFNLO agreed to check if the Spin-2 generator could be modified into a flexible reweighting function that can be applied on top of existing spin 0, CP even MC samples
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