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11/16 September 1998 to do list
An informal meeting was held in the CERN canteen this morning. We agreed on the following:
17 September 1998
Hi
A group of us attending the September Atlas Week who are interested in Electroweak top quark production met informally this afternoon to compare notes and begin working toward the TDR chapter. These minutes are to establish what we discussed and to insure that I have proper email addresses and names spelled correctly. I would appreciate a quick REPLY to this note to let me know that you got it and to tell me if you see any errors or ommissions in the followingdistribution list:
marina.cobal@cern.ch
parsons@nevis.columbia.edu
Stefano.Lami@cern.ch
mehdiyev@sunse.jinr.ru
lefebvre@uvic.ca
Dugan.O'Neil@cern.ch
slabospitski@mx.ihep.su
koukhtine@cern.ch
pineiro@pa.msu.edu
abolins@pa.msu.edu
yuan@pa.msu.edu
Present in our informal discussion were: Cobal-Grassmann, Lami, Mehdiyev, Slabospitski, Koukhtine, and Brock. 1. I proposed an outline for our part of the TDR which was slightly modified in discussion (add [4.5.1.6] as a prefix to all sections):
[4.5.1.6] EW Top Quark Production - introduction
[].1 Physics Measurements
.1.1 cross section(s), top width and V_tb
.1.2 polarization of top and W
.1.3 CP violation
.1.4 New physics
.1.5 others?
.2 Generators
.2.1 pythia and modified pythia
.2.2 onetop (Yuan, et al.)
.2.3 madgraph (Willenbrock, et al.)
.2.4 comphep (Belyaev et al.)
.2.5 others?
.3 Signal and Background separation strategies
.3.1 backgrounds
.3.2 gluon-fusion reaction
.3.3 Wt process
.3.4 W* process
.4 Experimental considerations
.5 Theoretical considerations and uncertainties
[4.5.1.6].6 Conclusions and future plans
------------------------------------------------------
(top)
I think that I heard agreement on the following points:
2. the standard ATLFAST ntuples will be the common "language" for signal and background montecarlo generation
- some analyses may include parton-level ntuples of the original hard processes, but they will be separate ntuples and not subject to standarization
3. We will likely create a central directory at CERN where the ntuples will reside. One should be able to rely on those data sets as the most recent versions, within their classifications. Those supplying ntuples are obligated to produce documentation to accompany the files noting program origination, algorithms, versions of standard software, notes, etc. I think it would be ideal if this documentations would be in the form of a web page which could be local to your institution. If you would rather supply TEXT, I'll convert it to HTML and post it.
- marina was going to check on available disk storage space and let me know if we need to supplement it. (The ATLFAST ntuples are large.)
4. I will produce a central web site which will point to each of the separate documents above as well as other pieces of useful information.
5. Various folks have produced W+jet background calculations. We agreed that it may prove important to have multi-jet, hard events passed through to ATLFAST, but that until that exists, pythia will be sufficient. Marina is going to revisit an atlas note on this subject that she co-authored with Pisa colleagues [ATL-PHYS-96-093...right, Marina?] (wrong...see below)
- In addition to standard W+jets calculations, it may prove useful, to have MC data sets in which heavy quarks are forced in each event.
- I think that we should freeze background calculations relatively soon so that calculations don't have to be redone.
6. We agreed that we should establish some benchmark distributions in order to compare calculations.
7. Stephan (wrong, Antonio!...see below) reported a problem with the pythia example in the ATLFAST documentation. The card, MSTP(48) is set =1, which results in W decay without proper polarization (just straight phase space?). The default is =2 and this card should be commented out. This is apparently the determination after a recent frustrating period of trying to understand the odd decay distribution.
8. I know of the following work which could be submitted soon:
- Rashid has pythia-generated gluon-fusion events with a slimmer ATLFAST ntuple format. He also has background calculations. - Serge has pythia-generated gluon-fusion events with a different implementation of pythia.
- For this meeting, Beatriz Pineiro generated ntuples based on the onetop code, through to the standard ATLFAST ntuple format.
9. I believe I heard interest in the following physics/calculations:
- gluon-fusion: Rashid
- Wt and W*: Serge ( I believe that the Victoria group is also interested in V_tb from W*? Please correct me if I'm mistaken.)
- polarization: MSU
- the "double-counting problem": MSU
10. To do, immediate (~1-2 weeks)
a. Establish central site for ATLFAST ntuples. *Marina and Chip*
b. Individuals should complete calculations in standard form and prepare documentation. *Rashid, Serge, MSU*
c. General EW Top quark web site. *Chip*
d. Folks should commit to specific writing responsibilities according to the outline above. *Group*
- The writing will eventually be submitted to me in ASCII form, with LaTeX formulas. I will test my version of Framemaker 5.5 and try to hand a file to Marina to see if we can go from Mac to Unix. If okay, I'll insert group's work into the TDR template for our sections. If not, I'll forward the whole mess to our Top Leaders with the request that we switch to LaTeX some day.
- We agreed that we will work toward a complete document, distilling it later to the few pages that we will be allowed.
- In one week, I'll send back to the group your stated commitments for writing, maybe with suggestions if there are big holes.
11. To do, longer term (~4-6 weeks)
a. Background decision..freezing our background plans for the TDR (I'm guessing that if we had to use pythia for the TDR, it would be okay for single top physics...?) I would suggest using the onetop-generated results forthe ttbar background in order to take advantage of the full density matrix results.
b. Calculation comparisons
c. Fine-detail outline with figures and captions (!) as mandated by the Atlas management for 10/31. As that date approaches, we can figure out just what to do.
12. To do, very long term (~few months)
a. Establish real Signal-Background separation strategies for each reaction. Of course, there may be multiple approaches, but they should be fully documented in order to appear in the TDR. I think that John and I will be attending the Fermilab top quark workshop... We will make an effort to get transparencies, if they are not posted on the web.
Please tell me if I've left something out or made mistakes. We should obviously plan to meet again during the November Atlas Week. I'll be in touch with you in the meantime as progress occurs.
Regards,
Chip
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Raymond Brock 207 Physics & Astronomy Bldg | Professor of Physics
Dept of Physics & Astronomy | and Chairperson
Michigan State University |
East Lansing, MI 48824 | brock@chip.pa.msu.edu
..................................................................
http://www.pa.msu.edu/~brock/chips_homepage_hot.html
Dept office:(517)353-8662
HEP office:(517)353-1693 Fax:(517)353-4500
fermilab office:(630)840-8795 home:(517)351-4287
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There were a few corrections to the minutes:
1. I misidentified Antonio Lagatta as "Stephano Lami". I apologize to Antonio and thank Marina for letting me know.
2. I failed to include Sylvain Negroni as a member of this group. He is at Marseille and is working on R-parity violating SUSY as an exotic source of single top quarks.
3. I believe that I misidentified the ATLAS note that was relevant to W plus jets production, specifically regaring the VECBOS generator. It is correct on the publications page.
Questions from November Atlas Week
soon.
last modified:
Raymond Brock, Professor of Physics and Chairperson, Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824,