From: Stephen J. Sanders (ssanders@ku.edu)
Date: Mon Jun 23 2003 - 14:03:25 EDT
Hi JJ, Unfortunately, as Hiro noted in his last message, each of global detectors has its own idiosyncratic behavior. Our confidence in these detectors is largely based on finding consistency between the detector systems and, in particular, being able to directly relate the mult array results to tpm1 counting measurements. It is not obvious that the BB array is in any better shape for a quick centrality measurement than the SiMA or the TMA--As Hiro points out there have been significant gain shifts in the BB array. Also, remember that the background correction for the BB array is tricky--Recall the arguments that we went through when Yuri was doing the initial Au+Au analysis... So, the relative central to peripheral shape characterization can certainly be done with some careful wording so as not to mislead the reader. The calibration of the global detector systems is being vigorously pursued, but since this has to be done using extensive geant simulation (a VERY time consuming task!) the more interesting R_dA comparison may not be possible for a couple more weeks. Regards, Steve On Monday, June 23, 2003, at 11:37 AM, Jens Jørgen Gaardhøje wrote: > Dear Steve > Indeed you touch on a central issue (excuse the pun). > We will take a look at the shape of the RAA for diff. centrality > cuts. As > we discussed in Krakow, however, some felt that this is not very > worthwhile, although I hold a somewhat different opinion. > Much better is of course to be able to plot the RAA for such cuts. This > requires proper Ncoll numbers. If the Si mult. dist is not understood, > perhaps > such cuts could be made on the BB and correspondingly simulated in > HIJING+BRAG. > Perhaps it would be most expedient to try to produce the numbers from > the > simulations using various cuts on the Si and BB, so that they are > available > if we decide to use them. > Item 1. should at least give us confidence in what we are doing. > > We would also be very happy for fisrt thoughts on the paper draft and > not > least on more fancy figures. > > Claus is now back. We hope that a reanalysis of the y=2 data will be > available sometime tomorrow. Peter has redone the DST's etc. with > updated D1 > and D2 info + geom. > > cheers > Jj > > ____________________________________________________________ > Jens Jørgen Gaardhøje, Assoc. Prof., Dr. Sc. > Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen, Denmark. > Tlf: (+45) 35 32 53 09, secr. (+45) 35 32 52 09, Fax: (+45) 35 32 50 > 16. > UNESCO Natl. Comm., secr. (+45) 33 92 52 16. > Email: gardhoje@nbi.dk. > ____________________________________________________________ > > > ----- Original Message ----- > From: "Stephen J. Sanders" <ssanders@ku.edu> > To: <brahms-l@bnl.gov> > Sent: Monday, June 23, 2003 5:42 PM > Subject: Re: High pt paper > > >> Hi, >> In reading through the draft I'm struck by how unfortunate it is that >> we don't have >> centrality selection for the dAu. There would seem to be two >> "features" of the reaction >> that we are unable to address: >> 1.) Does the shape of the nuclear modification function change with >> centrality, as seen >> with the Au+Au data, >> 2.) Does the amplitude of the hard scattering region of the nuclear >> modification function change >> with centrality, as seen dramatically by Phenix, but seemingly less so >> by Phobos and >> Star. >> >> We can't answer the second without real centrality selection and an >> analysis of >> Ncol. However, I wonder if it would be worthwhile to address 1.) by >> adding a >> central/peripheral ratio vs Pt. I could imagine a comparison on the >> 50% highest >> tile multiplicity with the 50% lowest. >> >> Just a thought... Question 2.) is probably much more interesting, >> but is looking increasingly >> unlikely to be ready by the time we need to submit.... >> >> ...steve >> >>> >>>> >>>> Dear Collaborators, >>>> >>>> I've updated the high pt paper draft. The changes are mainly of >>>> the language (thanks to J. Natowitz). I've added a bit and >>>> re-arranged >>>> the analysis and hardware section. Don't focus too much on the text >>>> describing the figures since this will be re-writtin when we have >>>> the >>>> final figures. >>>> >>>> The new draft is here: >>>> >>>> www.nbi.dk/~ekman/highpt/high-pt26.ps >>>> www.nbi.dk/~ekman/highpt/high-pt26.pdf >>>> www.nbi.dk/~ekman/highpt/high-pt26.tex >>>> >>>> Claus >>>> >>>> >>> >> >> >> > >
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