The STAR experiment

View of module-0 resting on the movable table looking upstream.

View of module-0 resting on the movable table. Visible are the markings for the 12 towers being calibrated.

STAR EMC collaborators and AGS staff work to install module-0 at the AGS test beam.

Module being placed on the movable table at the B2 test beam facility.

Module suspended by AGS crane being placed on the movable table at the B2 test beam facility.

Construction photograph of STAR showing the alignment of the rails for the EMC.

Construction photograph of STAR taken on May 28, 1998. Visible in the picture are the rails and supports for the STAR EMC.

This page was written by Marcia Maria de Moura in January 2005 and ported into Drupal in October 2007

This is a study of 2005 data conducted in May 2006.  Ported to Drupal from MIT Athena in October 2007

Hi jetters. Mike asked me to plot the charged track / pion asymmetries in a little more detail. The structure is the same as before; each column is a trigger, and the four rows are pi+/Yellow, pi+/Blue, pi-/Yellow, pi-/Blue. I've split up the high pt pion sample (2< pT < 12 GeV) and plotted single-spin asymmetries for timebins 7,8, and 9 separately versus pT and phi.  The plots and summaries are linked at the bottom of the page.

2 sigma effects are highlighted in yellow, 3 sigma in red. There are no 3 sigma asymmetries in the separate samples, although pi-/B/JP1 is 3 sigma above zero in the combined sample. Here's a table of all effects over 2 sigma:

If you compare these results with the ones I had posted back in March (First Look at Single-spin Asymmetries), you'll notice the asymmetries have moved around a bit for the combined sample. The dominant effect there was the restriction to the new version of Jim's golden run list. The list I had been using before had at least two runs with spotty timebin info for board 5; see e.g.,

http://www.star.bnl.gov/HyperNews-star/protected/get/jetfinding/355/1/1/1.html

and ensuing discussion. I'm in the process of plotting asymmetries for charged track below 2 GeV in 200 MeV pT bins and will post those results here when I have them.

This is a study of 2005 data conducted in March 2006.  Ported to Drupal from MIT Athena in October 2007

eL_asymmetries.pdf
phi_asymmetries.pdf

This is a study of 2005 data conducted in March 2006.  Ported to Drupal from MIT Athena in October 2007

Goal: Quantify the relationship between the z-vertex position and the bbc timebin for each event.

Procedure: Plot z-vertex as a function of trigger and bbc timebin. Also, plot distributions of bbc timebins for each run to examine stability. Exclude runs<=6119039 as a result. Fit each vertex distribution with a gaussian and extract mean, sigma.  Plots are linked at the bottom of the page.  See in particular page 8 of run_plots.pdf, which shows the change from 8 bit to 4 bit onlineTimeDifference values.

Timebin 12 had zero counts for each trigger. Summaries of the means and sigmas:

Conclusions: Hank started the timebin lookup table on day 119, so this explains the continuous distributions from earlier runs. In theory one could just use integer division by 32 to get binned results before this date, but it would be good to make sure that no other changes were made; e.g., it looks like the distributions are also tighter before day 119.  Examining the vertex distributions of the different timebins suggests that using timebins {6,7,8,9} corresponds roughly to a 60 cm vertex cut. A given timebin in this range has a resolution of 30-45 cm.