Spin PWG

This is a feed of Drupal items targeting the "Spin" Audience.

Cut Variation Tests


To test the stability of the cross section measurement to changes in the analysis cuts and, if necessary, assign a systematic uncertainty for cut variations.

Early Studies


Preliminary Result

Longitudinal double-spin asymmetries for inclusive charged pion production opposite a jet

Jigsaw Fits (2nd try)

 Following up from this post concerning the modeling of the invariant m

Paper Proposal

Cross section and longitudinal double-spin asymmetr

2005 Charged Pion


Candidate Level Comparisons


Data/Filtered Pythia Inv. Mass Distributions


Data Vs. T2 Platinum (see here)


Run 6 Data / Monte Carlo Comparison

Partonic Cross Sections

xsec = {
'3_4' : 1.302,
'4_5' : 3.158E-01,
'5_7' : 1.372E-01,
'7_9' : 2.290E-02,
'9_11' : 5.495E-03,
'11_15' : 2.220E-03,
'15_25' : 3.907E-04,
'25_35' : 1.074E-05,
'35_45' : 5.000E-07,
'45_55' : 2.857E-08,
'55_65' : 1.451E-09

Normalization Procedure

I calculated the integrated luminosity for my dataset (5.43 pb^-1) and scaled all event- and jet-level histograms by that amount (in mb^-1 to match the partonic xsec numbers above). For the track histograms I added a multiplicative factor of 0.82 to account for imperfect PID efficiency in the data. I neglected PID contamination.

Run 9

Collect documentation on run 9 here.


<z> Details

<z> Details


A_LL Details

Details on the A_LL result and the systematic studies:

The result in numbers:

Bin <p_T> [GeV]

Neutral Pion Paper: 2005 ALL & <z>

Neutral Pion Paper for 2005 data: Final Results.

There are two spin plots planned for the paper, one with the 2005 A_LL and one with the <z>.

Group Meeting Update

Progress towards a measurement of A_{LL} for charged pion production opposite a trigger jet using data from the 2006 STAR run. Goal is to present this measurement as a function of z, defined here as p_{T}(pi) / p_{T}(trigger jet).

Update 2008-08-28: added data/MC comparison plots

Jigsaw Fits (1st try)


Data Sets

For the cross section analysis I am using a number of Monte Carlo samples along with one data set.  The details of each of these sets can be found below:


Cross Section Analysis

On the pages listed below I'm going to try to keep track of the work towards measuring the cross section for inclusive pion production in pp collisions from run 6.  I'll try to keep the posts

2008.08.14 Shower shape with bug fixed dd-library

Ilya Selyuzhenkov August 14, 2008

Data sets:

Working Group Members

If you perform work within Spin/Cold-QCD physics working group, please a

CDEV Monitoring

(Archived into Drupal from MIT servers in August 2008. Original analysis by Julie Millane and Bernd Surrow.)