Motivation:

In d+Au Ridge study, 0-20% and 40-100% have been analyzed for central and peripheral. See drupal.star.bnl.gov/STAR/blog/yili/dau-ridge-global-tracks-inclusive-charge.

Cent-R*Peri method has been discussed and two double-ridge is found.

Here we'd like to go to more peripheral 60-100% and more central 0-10% to investigate whether conclusion will be affected. Or in another word, if there is flow/ridge in 40-100%, how large the contribution will affect the subtraction result. 

Method:

Dihadron correlation.

Fit near-side Δη with Gaussian + Pedestal. Fit parameters Y for Gaussian area, σ for Gaussian width, C for pedesta. For both central and peripheral.

1. Near-side jet yield central over peripheral ratio R.

2. Cent - R x Peri for dihadron correlation

Global tracks.

For events with |Vz|<50 cm:

FTPC East (Au-going) refMult centrality:

M >= 23         9.2%
M >= 22         10.6%
M >= 18         18.1%
M >= 17         20.5%
M >= 11         39.4%
M >= 10         43.4%
M >= 7          56.9%
M >= 6          61.9%

So

[22, 500] for 0-10%
[6, 21] for 10-60%
[0, 5] for 60-100%

ZDC East (Au-going) Attenuated ADC

ADC >= 134              9.3%
ADC >= 133              10.7%
ADC >= 129              17%
ADC >= 128              18.7%
ADC >= 127              20.6%
ADC >= 117              39.1%
ADC >= 116              40.8%
ADC >= 101              59.6%
ADC >= 100              60.5%

So

[133, 500]  for 0-10%
[100, 132]  for 10-60%
[0, 99] for 60-100%

For events with |Vz|< 30 cm:

FTPC East (Au-going) refMult centrality:

M >= 23           9.8%
M >= 22         11.2%
M >= 18         18.9%
M >= 17         21.3%
M >= 12         36.7%
M >= 11         40.4%
M >= 10         44.4%
M >= 7           57.8%
M >= 6           62.8%

ZDC East (Au-going) Attenuated ADC

ADC >= 134              9.5%
ADC >= 133              10.9%
ADC >= 129              17.3%
ADC >= 128              19.0%
ADC >= 127              20.8%
ADC >= 117              39.3%
ADC >= 116              41.0%
ADC >= 101              59.8%
ADC >= 100              60.7%

Data set:

Run3

|Vz| < 50 cm
nHitsFit > 25 points for TPC
nHitsFit > 5 points for FTPC
nHitsFit/nHitsPoss >= 51%
globa dca < 3 cm
|eta|<1 for TPC
2.8<|eta|<3.8 for FTPC
1<pT<3 GeV/c

Results:

1. Near-side jet Δη distribution

Both trigger and associated particles in TPC

FTPC centrality

R = Y^cent / Y^peri = 1.347

0-10%	60-100%

ZDC centrality

R = Y^cent / Y^peri = 1.2

0-10%	60-100%

The away-side shapes are also different.

2. Cent - R x Peri

FTPC centrality

TPC x TPC correlations

Red for central. Black for peripheral. Blue for scaled peripheral, scaled by R = Y^cent/Y^peri.

Cent-Peri

Cent-RxPeri

ZDC centrality

TPC x TPC correlations

Red for central. Black for peripheral. Blue for scaled peripheral, scaled by R = Y^cent/Y^peri.

The away-side shape in 0.5 < |Δη| < 0.7 for central and peripheral are not the same. The scaled peripheral is still lower than central.

Cent-Peri

Cent-RxPeri

TPC x FTPC correlations

Cent-Peri

Cent-RxPeri