The STAR experiment

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

Ok, after working on porting the BEMC webpages to Drupal over the past couple of days I have a list of features that I hope we can implement in our Drupal installation:

• Performance Optimizations:  I don't know if it's Drupal settings, PHP settings, or what, but this CMS is awfully slow at times.  I've set up a couple of Joomla installations at MIT that are much snappier.  This is the number one complaint I hear from other people.  It's going to be a running joke at EMC phone meetings before too long.
• Trash Bin:  What do I do with pages that I decide I don't want?  I don't see any way to trash them, so for the moment the BEMC subsystem page has a "Trash Bin" of it's own.  It sure would be nice if I could hide it, though.
• Authorship changes:  Sometimes I create pages as kocolosk that would probably be better off as staruser pages, but I don't see any way to change the authorship myself, so I've resorted on at least occasion to "trashing" the old page as best I could and then recreating a new page with a different author.  Very convoluted.
• Restricted viewership:  I would like to post analysis results in Drupal, but I can't figure out how to restrict my pages to logged in users.  At the moment I have a folder called drupal_pics in protected/spin that I put plots in.  Users are then required to type a password to see them, but again, this is something Drupal must be able to handle by itself.

Testing upload. Restored options (with head on shoulders).

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Starsim at PDSF seems to pick up different libraries than at rcf (I guess this is no surprise). The load of the default pythia library seem to fail for all tested library versions (SL06e, SL06f, starnew, starpro) - and it fails silently. Log file output includes a local checkout and compile of the pythia library seems to fix. Must replace the line in the kumac with the local library: with

As RCF moves towards the Condor batch system I thought I'd compile a list of some useful commands here.  The ones with a * next to them should be run from the node on which you submitted your jobs.  The full Condor 6.8.3 manual is at

Notes on embedding test sets for CuCu, P06ib. I ran several sets of embedding test files at PDSF, named Piminus_00x_spectra.

Set Number

Field

Notes

QA

	Chain init  + TEventList generation	Process TEventList
CINT	156 / 247	1664 / 1909
Python	156 / 257	1255 / 1565
Compiled C++	154 / 249	877 / 1209

I tried the Python code without using a TEventList.  The chain initialization dropped down to 50/70 seconds, but reading in all 26M events took me 1889/2183 seconds.  In the end the TEventList was definitely worth it, even though it took 3 minutes to construct one.

Conclusions:

1. Use a TEventList.  My selection criteria weren't very restrictive (event fired JP1 or JP2), but I cut my processing time by > 30%.
2. I had already compiled the dictionaries for the various classes and the reader in every case, but this small macro still got a strong performance boost from compilation.  I was surprised to see that the Python code was closer to compiled in performance than CINT.
   

In the 2003+2004 jet cross section and A_LL paper we quoted a 5% systematic uncertainty on the absolute BTOW calibration.  For the 2005 jet A_LL paper there is some interest in reducing the size of this systematic.

I went back to the electron ntuple used to set the absolute gains and started making some additional plots.  Here's an investigation of E_{tower} / p_{track} versus track momentum.  I only included tracks passing directly through the center of the tower (R<0.003) where the correction from shower leakage is effectively zero.

Full set of electron cuts (overall momentum acceptance 1.5 < p < 20.):

dedx>3.5 && dedx<4.5 && status==1 && np>25 && adc>2*rms && r<0.003 && id<2401

I forgot to impose a vertex constraint on these posted plots, but when I did require |vz| < 30 the central values didn't really move at all.




Here are the individual slices in track momentum used to obtain the points on that plot:







Electrons with momentum up to 20 GeV were accepted in the original sample, but there are only ~300 of them above 6 GeV and the distribution is actually rather ugly.  Integrating over the full momentum range yields a E/p measurement of 0.9978 +- 0.0023, but as you can see the contributions from invididual momentum slices scatter around 1.0 by as much as 4.5%

Next Steps?  -- I'm thinking of slicing versus eta and maybe R (distance from center of tower).