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Dear Joey, I will be glad to contribute to sections on jet substructure /boosted systems (part of item #4) and scale choice / jet veto (part of #2). I have been closely involved in CMS analyses dealing with these issues. Best Regards, Kalanand On 2/6/13 12:42 PM, Joey Huston wrote: > Here are some of the sub-groups for the Snowmass(-Les Houches) QCD group, plus a few leading (but certainly not complete) questions for each sub-topic. Please volunteer if you wish to add something to the research (and the writeup) on a particular topic. Please indicate what you would like to work on. You can respond to this email to volunteer. I put (Les Houches) in parentheses as other topics may also be pursued at Les Houches, but this is what we're thinking of for the Snowmass writeup. This need not be a complete list, so also please volunteer any omission that you note. > > 1) PDFs > -precision needed for the LHC, @current luminosity/energy, @ high luminosity and full energy, and for future energy/luminosity upgrades (this ties in with the expected > experimental uncertainties and the expected theoretical uncertainties for the LHC predictions) and the effect of PDF uncertainty for the particular physics topic) > -importance of QED/EWK corrections in PDFs, photon PDFs > -of particular interest are PDF uncertainties for Higgs production and for new physics (high masses) > -what LHC cross section measurements are needed for use in global PDF fits; what are current uncertainties, what are extrapolations to higher luminosity/energy data samples? > -the role of an eLHC; what are the expected PDF uncertainties at the time of an eLHC (and the limitations of the kinematic coverage); what can an eLHC contribute? > > 2) Higher order > -are there any important NLO processes that are currently un-calculated? what are the important NLO processes that have to be interfaced to a NLO ME+PS program? > -what are the possibilities/limitations for MEPS@NLO types of implementations for multi-parton matrix elements at NLO? what are the greatest needs from the experimental point-of- view > -how do current estimates of uncertainties on jet vetoed/jet-binned cross sections agree with each other? are such estimates 'universal'? how will NNLO calculations of the cross sections improve our understanding? how will the impacts of such jet vetoes/binning change with center-of-mass energy? > -what are the expectations for NNLO calculations in the short and medium term? what is the priority? > -how well do we understand scale choices/uncertainties for inclusive cross sections, especially those for which many scales are present (tTbB)? how well will a MINLO-type > procedure work and how does it compare to conventional scale choices such as HT/2; how well do we understand how to set the uncertainty range? > -how important are NLO EWK corrections compared to NLO/NNLO QCD corrections? what is the priority list for combined EWK+QCD corrections, especially given the > measurements at the LHC in the 'Sudakov zone' (>1 TeV) > > 3) Resummation > -what are the priorities for resummation in the near-term and medium-term? (e.g., Keith Hamilton said that we needed to know more about resummation in order to extend > MINLO Mk2 to more than 1 jet in the final state) > -to what extent do current formalisms to resum large logarithms in jet-binned cross sections agree? can what has been learned from Higgs(+jets) resummation be applied to > processes such as W/Z+jets? > > 4) Jets > -so far at the LHC, the antikT algorithm is almost universally used; for what physics analyses would it be useful to compare results to other algorithms, such as SISCone? for what > physics analyses would it be useful to compare the results to other jet sizes > -what is the current status of jet substructure analysis/boosted systems? can we put these tools to more universal use in general physics analyses at the LHC? > -at what future luminosities might existing jet algorithms cease to be robust? what techniques may be introduced to stabilize them? > -what are the physics possibilities of using particle flow techniques in future jet algorithms? > -how can we make more use of jet shape variables such as n-jettiness in general physics analyses? > > 5) Diffraction and non-perturbative physics > -are there gaps in our understanding of diffractive and hard diffractive physics? > -how does the photon-photon flux in a pp machine compare to that in a future linear collider? for what physics topics would such measurements be useful? > -how hampered are we by our current limited understanding of non-perturbative physics? what measurements/phenomenology can we do to improve this? > > regards, > > John Campbell > Ken Hatakeyama > Joey Huston > Frank Petriello ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the SNOWMASS-QCD list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=SNOWMASS-QCD&A=1