The STAR experiment

Talk given by James Dunlop.

Time	Talk	Presenter
09:00	Call backs for panel members/presentations left from previous day ( 01:00 ) 0 files	(All)
10:00	Committee discussion, preliminary findings ( 01:45 ) 0 files	(All)
12:45	TPC review closeout report ( 00:15 ) 1 file	(All)

Time	Talk	Presenter
11:10	TPC Distortions: present tracking performance ( 00:30 ) 1 file	Jim Thomas (LBNL)
11:40	STAR TPC distorions - Correction Efforts ( 00:50 ) 1 file	Gene Van Buren (BNL)
12:30	STAR TPC dE/dx resolution ( 00:30 ) 1 file	Yuri Fisyak (BNL)

Time	Talk	Presenter
09:00	Overview of basic operating parameters for the STAR TPC ( 00:15 ) 0 files	Dick Majka (Yale)
09:15	Expected evolution of RHIC luminosity for p+p,p+A, and A+A collisions; implications for track loading, and pile up (projections) ( 00:20 ) 1 file	Dick Majka (Yale)
09:35	Overview of major STAR p+A, and A+A physics goals, requirements for High Pt, HF, Secondary, ( 00:40 ) 1 file	James Dunlop (BNL)
10:15	STAR p+p physics goals; requirements ( 00:40 ) 1 file	Mike Miller (MIT)

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There remains a possible distortion due to a potential short in the OFC west as well. We see a bimodal pattern of 0 or 80 excess nanoAmps coming out of the OFC West field cage resistor chain (it has been there since the start of the 2005 run). That corresponds to a 0.38 MOhm short (420nA = 2 MOhms). The corresponding distortion depends on the location of the electrical short. The plot shown here is the distortion in azimuth (or rPhi) at the outermost TPC padrow near the sector boundaries (r=195 cm, the pads are closer to the OFC near the sector boundaries) due to such a short between different possible field cage rings:

In terms of momentum distortion, a 1mm distortion at the outermost padrows would cause a sagitta bias of perhaps about 0.5mm for global tracks (and even less for primary tracks), corresponding to an error in pt in full field data of approximately 0.006 * pt [GeV/c] (or 0.6% per GeV/c of pt). This is certainly at the level where it is worthwhile to try to fix the distortion if we can figure out where the short is. It is also at the level where we should be able to see with the lasers perhaps to within 50cm where the short is.

Just as a further point of reference, the plot for radius = 189cm, corresponding to the radius of the outermost padrow in the middle of a sector (its furthest point from the OFC) can be found here.

This possible distortion remains uninvestigated at this time.

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Gene Van Buren
gene@bnl.gov

Statistical errors from MB || JP1 || JP2 from 2005:

I re-examined the data - pythia comparison in my analysis after some good questions were raised during my preliminary result presentation at today's Spin PWG meeting. In particular, there was some concern over occasionally erratic error bars in the simulation histograms and also some questions about the shape of the z-vertex distributions.