A general introduction to the Interference Fragmentation Function can be found in the attached file 'nccIFFTransversityOnlineFirst.pdf'.

This analysis at Star uses charged particle Tracks. Combinations with neutral pions have also been analyzed but the since the signal is significantly smaller and the systematic effects are more difficult to quantify they will be released at a later time.

Dataset:

2006 pp transverse, (same as for the Collins analysis)

Use bad run lists and rel lumi's from Rob. 

Max Z vertex: 60cm

Trigger: 

 Use most triggers that read out TPC and trigger on events that have central activity. Main contributing triggers are JP0 and HT triggers.

Here the list of IDs:

127221, 127262, 127271, 117450, 127501, 127551, 127571, 127575, 127580, 127585, 127611, 127622, 127641, 127652, 127821, 127831, 127831;

Track selection:

pt>1.5, dca<2, numberOfFitPoints>15, PID: abs(nSigmaPion) <2.

Use all +/- pairs in one event. Require cone cut of 0.3 (investigate looser cut) to make sure that particles come from same jet

Min separation of 0.05 in (phi,eta) space, otherwise phiRS distribution (see below) has spike around pi/2 probably due to wrong extrapolation of phi at vertex. Here a small error leads to a change of orientation of the two hadron plane.

Allow tracks in -1.4 < eta<1.4. But asymmetries are virutally unchanged if restricted to the barrel, due to low statistics in the tail (see below)

Observable: