Flow analysis using MRS/FS

H. Ito

4 separate angles: 4, 8(not quite done), 40 and 90 deg

Pion and hopefully Proton (will not be shown)

Zoom

TFW2 PID

TFW2 is used for PID in MRS

Looks good upto here?

TFW2 Pi-K separation at 90 deg

2.4 – 2.6 GeV/c

2.6 – 2.8 GeV/c

2.8 – 3.0 GeV/c

Would C4 help?

What is the regection (or contamination) factor of C4?

Difference from theoretical line

3 sigma cut

Cuts are done in 2D pid plot by comparing to theoretical line.

It assumes that beta and P have the same resolution ---> ???

Pion selection in MRS by TFW2

Tfw2 Mass2

Pion Cut

Centrality 0-50%?

Missing events

Spectrometer trigger tends to select more central events.

Dividing events in smaller centrality range is ideal. But, there may not be enough events to divide.

Particularly, peripheral events are hard to come by.

v2 from MRS at 90 degree

MRS 90 deg

Pion

0-50% central

Correction = 0.204

-> ~ 5 times

Uncorrected

Corrected

Pion

V2 from MRS at 90 degree

20-50% central

MRS 90 deg

Correction = 0.233

-> It is better than 0 – 50% selection

Pion

Uncorrected

Corrected

Pion

Centrality dependence 90 deg

Uncorrected

Red 20-50%

Blue 0-50%

Pion

2.4 – 2.6 GeV/c

TFW2 Pi-K Sepration at 40 deg

2.6 – 2.8 GeV/c

2.8 – 3.0 GeV/c

V2 at 40 deg

Pion

Red: 0 – 50 %

Black: 20 – 50 %

Corrected

Uncorrected

RICH PID

24 – 26 GeV/c

26 – 28 GeV/c

28 – 30 GeV/c

Pion selection in FS by RICH

Cuts are currently done by RICH MASS. It will be changed to difference from the theoretical line.

Pion cut

Uncorrected

Red: 20 – 50 %

Blue: 0 – 50 %

V2 at 4 deg

Pion

Corrected

STAR

Things to do

To increase statistics for low Pt , use H1 + C1

What is the regection factor in C1?

To increase PID range in MRS, use C4

What is the regection factor in C4?

See how Proton is doing?

See how Kaon is doing?

Theoretical prediction ---> Punch line?

Hironori Ito

2005-06-09T11:12:31