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1 IST layer

Speaker : Gerrit van Nieuwenhuizen ( MIT )


Talk time : 13:40, Duration : 00:10

AOB

Speaker : All


Talk time : 13:50, Duration : 00:10

Single track efficiencies

Speaker : Willie


Talk time : 13:20, Duration : 00:20

QA on 0.5x luminocity

Speaker : Jan


Talk time : 13:00, Duration : 00:20

See hypernews for his web links

Autobuild & Code Sanity

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This page will contain results from code-sanity tools i.e. tools checking for code syntax, memory leak, profiling etc ... and tips on how to correct those problems.

Comparing Pion-Kaon correlations from data and Therminator

A Brief Overview of the New Pixel Fast Simulator

The new StPixelFastSimMaker imposes the pixel structure on the PXL detector and the strip structure on the IST detector.  For each event the simulator loops over StMcPixelHits, determines which p

g-g suppression in Pythia

I'm concerned about an apparent deficit of g-g scattering events in our CDF Tune A Pythia samples.  I first noticed this deficit when I was looking at MC asymmetries for pi-minus production, where the difference between asymmetries from g-g and q-g events is extreme.  For reference, here is Vogelsang's prediction for the subprocess mixture for inclusive pi0 production:

Compare that to the following plot from Pythia for pi-plus production after combining partonic samples starting at 3_4:

If I add 2_3 GeV the gg contribution at low pT gets a boost, but I'm still seeing ~zero pions from g-g scattering at 8 GeV, where Vogelsang predicts 20% g-g. 

Renee suggested skipping the observables and just plotting the event partonic pT.  The turnover from gg to qg occurs at 3 GeV ... seems too low to me.  On the other hand, the mixture is ~20% g-g at 16 GeV, which seems about right.

One other tidbit for any Pythia tuners out there.  When I was running standalone Pythia to get the various partonic xsections for weighting purposes I saw a number of advisory warnings like

Advisory warning: maximum violated by 1.120D+00 in event 625
XSEC(28,1) increased to 5.982D-01

in this case, I was running the 5_7 sample.  The initial max value for the q-g xsec was 5.3392D-01, and the final measured xsec was 1.515D-01.  Not sure if it's significant.

Update 11-19-2007

I looked into the relationship between charged pion p_{T} and event partonic p_{T} in more detail.  Here are plot of charged pion multiplicity and mean pion p_{T} versus event p_{T}:

so g-g events actually produce more charged pions per event, but these pions are all at low p_{T}.  The second conclusion is reinforced by the PDF I've linked at the bottom of the page, which shows pion p_{T} spectra split by subprocess for a range of partonic p_{T} bins.  The g-g events have a much steeper slope.  Those plots are not normalized by the # of events per subprocess, so the conclusion about the number of pions per event is not immediately evident.

Update 11-27-2007

I tried manually rescaling the g-g scattering contribution to the PYTHIA asymmetries; it looks like increasing the g-g by a factor of 5 does a decent job of reproducing the NLO theoretical predictions:

no rescaling

multiply g-g by 3.0

multiply g-g by 5.0

References

Agreement Between "Polarized" Pythia and NLO pQCD
Updated Charged Pion A_{LL} predictions

Parallel Photon Studies

In working toward a prompt photon cross section measurement, we are using two analyses in parallel.  The first is a two dimensional fit using parameters identified in the earlier OPAL and ZE

FAQs and Tips

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Software Site Licenses

Do we have a site license for software package XYZ?

The answer is (almost) always: No!

nodeaccess: Access settings by a user for a specific node

nodeaccess: Access settings by a user for a specific node

Nodeaccess: settings for a specific node type (admin settings)

Nodeaccess: settings for a specific node type (admin settings)

Updated look at Electrons in BEMC for 2007

I've had a chance to incorporate the st_upsilon production into my check on the BEMC tower calibration.  There are now enough statistics to look at individual towers (see

Nodeaccess: allowed roles (admin settings)

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Nodeaccess: allowed roles (admin settings)

Nodeaccess: allowed roles (admin settings)

AOB


Talk time : 00:40, Duration : 00:20

Software Status


Talk time : 00:20, Duration : 00:20

Response to Tim's E-mail

Speaker : All


Talk time : 00:00, Duration : 00:20

(If you have not received, it send a message to HM.)

Comparison between Normal and Test Runs (TPC Drift Problems)

This is my first post to drupal so I will limit it to two graphs
of the multiplicities for nTracks and nPoints for jets, comparing

New polarized gluon distributions in Pythia

So we now have access to a wide variety of gluon polarization parameterizations in our Pythia afterburner covering the regions between GRSV -std and -max and between GRSV -zero and -min.  Dave Staszak documents the details of the new distributions at

http://www.star.bnl.gov/protected/spin/staszak/2006/Sims/trigBias/trigBias.html

Here are plots of the raw charged pion asymmetries obtained from these grids (p070 excluded because of a bug on my part):

I suspect the problem with the pi-minus asymmetries can be traced to a lack of gg contributions.  For more information see Agreement Between "Polarized" Pythia and NLO pQCD.  In the remainder of this document I'll stick to analyzing pi-plus data.

I've attached multi-page PDF at the bottom of the page.  Each page of the PDF plots, for a give input gluon polarization distribution A_{LL}(trigger) - A_{LL}(no trigger) as a function of pion p_T.  There are six plots on each page; one for each trigger in (minbias, HT1, HT2, JP1, JP2) and then the raw A_{LL}(no trigger) distribution itself in the bottom right.  I believe one way we can obtain a systematic uncertainty from plots such as these is to calculate a double-sided max( delta A_{LL}, uncertainty on triggered A_{LL} ) for each pT bin we use to make our measurement.

One question is which grids are appropriate ones to use for calculating the systematic.  GRSV-max has been excluded in other measurements, so I don't think it's appropriate.  All other grids are fair game, which means the systematic will likely be derived from GRSV-min and p070 (once I rerun; use p060 for now).