Dear Joey,

I will be happy to contribute to the PDF section of the snowmass 
writeup. Which is the deadline? After or before the big workshop
in June?

We probably will have NNPDF with QED effects by then, so I should be 
able to add something to the QED and EWK corrections as well.

I also think that some dedicated effort should be devoted to whether or
not we are properly estimating PDF errors for high mass BSM production.
In these extreme region many of the approximations used are not valid
(like gaussian behaviour), and given the importance for searches, it
is timely to add it to the snowmass list.

Best,

Juan

------------------------------------------
Dr. Juan Rojo
Physics Department, TH Unit
Case C01600, CERN
CH-1211 Geneva 23 Switzerland
Phone: (+41) 2276 77943
Webpage: http://cern.ch/juan.rojo
E-mail: [log in to unmask]
         [log in to unmask]
Skype: juanrojochacon
------------------------------------------

On 2/6/13 7:42 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