pp 500 GeV Year 2012 Dihadron Correlation with TOFMult4+TOFmult3*VPD data

Updated on Wed, 2015-10-07 12:11. Originally created by yili on 2015-09-29 21:50.

Motivation:

Followed the pp 500 GeV Year 2013 EEMC-dijet trigger dihadron correlation where near-side Dphi distribution shows a bump with |Deta|>1.3.
See: drupal.star.bnl.gov/STAR/blog/yili/pp-500-gev-year-2013-dihadron-correlation-eemc-dijet-data

See follow-up on MB trigger: drupal.star.bnl.gov/STAR/blog/yili/pp-500-gev-year-2012-dihadron-correlation-vpdmb-nosmd-0
Similar result also seen in pythia simulation: drupal.star.bnl.gov/STAR/blog/yili/pp-510-gev-pythia-dihadron-correlation-hardqcd-20151007

Not sure whether it is only a trigger issue.

Here I check another year with a different triggers. The high-multiplicity trigger.

See master page: drupal.star.bnl.gov/STAR/blog/yili/master-page-dihadron-pp-500-gev

Dataset:

pp 500 GeV
Year 2012
filetype=daq_reco_MuDst,events!=0,trgsetupname=pp500_production_2012,filename~st_physics,production=P13ib,storage!=hpss,sanity=1
trigger id = 380616 -- TOFmult3*VPD, 380617 -- TOFMult4

Cuts:

|Vz|<50 cm
nHits >= 25 points
nHits/nHitsPoss >=0.51
|dca|< 3 cm
|eta|<1

Method:

Dihadron Deta-Dphi correlation.

Not normailzed (a.u.). mixed event corrected.

All TPC tracks are required to matched to BEMC of BTOF to reduce pileup effect.

1<pT<3 GeV/c for both trigger and associated particles

Mixed event:
<= 5 tracks difference in Ntrk in TPC
<= 5 cm difference in Vz

Result:

1. refmult distribution:
refmult is read from Mudst directly, no pile up removal matching.
(events < 2 tracks are not included in histogram)