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LHC EWK working group discussion
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Europe/Zurich
14/4-002 (CERN)
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16:00
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16:10
Introduction 10mSpeakers: Joshua Milo Kunkle (University of Maryland (US)), Senka Duric (University of Wisconsin-Madison (US)), Vasiliki Kouskoura (Brookhaven National Laboratory (US)), Yusheng Wu (University of Michigan; Institute of Physics, Academia Sinica)
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Minutes for LHC EWK multiboson meeting on September 5th, 2016
Participants: about 20 (Vidyo + Room)
https://indico.cern.ch/event/565681/
Introduction Slides
- Discussion of goals and possible future topics for the EWK multiboson meeting
- Marc-Andre / Matt in process of understanding conversion between aGC parameterizations and comparison between experiments, may have sth. to report in one month time scale
- About status of the anomalous coupling note: plan to check with Adam/Francesco before the next meeting and report to the group and discuss about possibility for ATLAS/CMS to contribute to the recommendations
- About statistical tools for future ATLAS+CMS combination: ATLAS used TGClim, which has been discontinued since a while ago; CMS is using Higgs tools which is maintained within the CMS software release and may not be trivial to use outside. ATLAS may think about moving to Higgs tools in the future.
Presentation by Alex Juergens on a try to derive aTGC limits with different upper cuts on the distribution
- Discussion about the methodology: it was suggested that a good way is to keep the data as it is but remove the aGC contribution in the MC distribution for regions above the upper cut value.
- Continuation of discussion on methodology: the suggested approach seems to be reasonably well received, however studies and checks have to be made and discussed in follow-up meetings. Alex / Kristin plan to check this method in the next update.
- Further study about sensitivity to a high-mass resonance: Alex / Kristin already have some models to work with, may report in a future meeting.
- About the advantage of this method against the original method of setting limits with different form factors: some insights may be read from arXiv:1604.06444v1
- The implementation of form-factors in 8 TeV ATLAS WW paper (page 13): about this form of "dipole form factors", one can refer to one of the references, arXiv:hep-ph/9503425.
Presentation by Yurii Maravin on aGC reweighting studies with Madgraph_aMC@NLO
- "SM+NP" gives better description in tails comparing to usual reweighting method.
- "SM+NP"+Reweighting may not work (i.e. to reproduce the distribution generated with exact parameter values) if the extrapolation of parameters is large (e.g. from large positive to negative values), the reason is unclear yet (to follow up).
- This problem may be a bug and fixed in a newer MG version? May try v2.4.0, also could look at decay angles and check if any obvious problems.
- Could unitarization work with the NP or the usual reweighting methods? This hasn't been tried yet.
- The conclusion is this SM+NP method doesn't fully work for the time being, for new future analyses, the usual reweighting technique should be applied.
A.O.B.
- Plan to have monthly meetings in the future (or biweekly if needed), and will circulate another doodle poll to fix the meeting time.
- About future topics: items listed in the introduction slides + additional topics such as discussion of electroweak corrections in VV analyses, 2D aGC summary plots, how to present our aGC results in HepData (3D likelihood or other forms), and etc.
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16:10
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16:40
Cut off scale studies (20' + 10') 30mSpeakers: Alexander Juergens (Deutsches Elektronen-Synchrotron (DE)), Kristin Lohwasser (Deutsches Elektronen-Synchrotron (DE))
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16:40
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17:10
NP > 0 reweighting studies (20' + 10') 30mSpeaker: Yurii Maravin (Kansas State University (US))
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17:10
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18:00
A.O.B. 50m
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16:00
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16:10