# Presentation: 717363

## RHIC CNI Polarimeter status

- RHIC CNI Group
- February 26, 2008

## HJet: Blue1

- 2/ndf = 6.5/6

- 33 Hours, 10 stores, 1.4M events

**Statistics uncertainty only**
**Rough event selection**
**TOF width cut (+/- 10nsec)**
**Channel 2-3 width selection**
**No background correction.**

**HJet: Blue1**

## HJet: Blue1

| Fill# | H-Jet Events |
| --- | --- |
| 9885 | 50427 |
| 9888 | 94430 |
| 9890 | 37767 |
| 9897 | 72279 |
| 9898 | 176010 |
| 9901 | 21035 |
| 9902 | 162664 |
| 9905 | 179075 |
| 9906 | 358828 |
| 9909 | 213666 |
| total | 1366181 |

**P****BLUE****=0.486 ******** 0.023**

## HJet: Blue2

- 2/ndf = 1.9/6

- 25 Hours, 3 stores, 1.4M events (Feb. 24-26)

**Statistics uncertainty only**
**Rough event selection**
**TOF width cut (+/- 10nsec)**
**Channel 2-3 width selection**
**No background correction.**

**HJet: Blue2**

## HJet: Blue2

| Fill# | Events | <PBLUE> |
| --- | --- | --- |
| 9942 | 472968 | 0.4310.040 |
| 9948 | 401223 | 0.3870.042 |
| 9949 | 523399 | 0.4090.036 |
| total | 1397590 | 0.415  0.023 |

## HJet: Yellow

**P****YELLOW****=0.384 ******** 0.021**

| Fill# | H-Jet Events |
| --- | --- |
| 9919 | 215906 |
| 9920 | 282587 |
| 9935 | 213772 |
| 9937 | 261714 |
| 9938 | 353033 |
| 9939 | 362811 |
| total | 168923 |

## HJet: Yellow

**HJet: Yellow**

- 2/ndf = 9.8/6

- 31 Hours, 6 stores, 1.7M events

**Statistics uncertainty only**
**Rough event selection**
**TOF width cut (+/- 10nsec)**
**Channel 2-3 width selection**
**No background correction.**

## pC: Online Polarizations 

**pC: Online Polarizations**

- Only scan measurements at store
- Measures average polarization over trans. profile
- This is what directly (should) relate to HJet measurements, but...

- Absolute scale in not yet fixed

**A****N**** from Run4!**

**Latest fills not yet included**

## pC: averaging

**pC: averaging**

- Mainly in blue:
- Intensity profile is flat 
- we stay longer at beam center than at periphery 
- measured polarization is closer to Pmax than to <P>
- <P>/Pmax ~ 0.93 for blue, see next slides
- Yellow looks fine for this

**Latest fills not yet included**

## Polarization Profile

- 
- 
- 

*P*(*L/L**max*): just an example

- If there are problems with target position determination 
- Exclude position from calculations:

*R*=0.290.07

**Latest fills not yet included**

## Polarization Profile

- R vs fill

- <R> ~ 0.28
- <P>/Pmax ~0.88

- <R> ~ 0.16:
- <P>/Pmax~ 0.93

- Run5/6: R~ 0.100.15

**Latest fills not yet included**

## pC vs Hjet

**pC vs Hjet**

- HJet-yellow

- HJet-blue

- Ponline(pC)/P(Jet)=1.060.06
- -1%: C energy correction and cuts (online/fast_offline difference)
- +7%: change in AN

**A****N**** from Run4!**

- Ponline(pC)/P(Jet)=1.170.06
- +6%: from “bad” scans _in this period_ (flat intensity profiles)
- +4%: C energy correction and cuts (online/fast_offline difference)
- +7%: change in AN

- AN(Run5)/ AN(Run4) ~ 1.01
- AN(Run6)/ AN(Run4) ~ 1.15

**Latest fills not yet included**

## Fast offline, normalized to HJet

- Normalization uncertainty
- (stat. only)

- Feb 23

- Feb 14

**Latest fills not yet included**

## Summary

- HJet demonstrates very stable/consistent measurements
- Consistent target asymmetry vs -t (with the same target polarization)
- Same (and even lower in Run8) background level
- pC data
- Polarization profile in blue is similar to Run5/6; polarization profile in yellow is sharper
- Experiments see more polarization than HJet due to intensity squared weighting: by 7%-relative in blue and by 12%-relative in yellow (if vertical and horizontal profiles are the same!)
- Blue-online polarizations are overestimated by (176)%-relative
- +7% - from AN (compared to Run4)
- Yellow-online polarizations are overestimated by (66)%-relative
- +7% - from AN (compared to Run4)

## Backups

## Hjet: Background level

- 1.2 <TR <2.5 MeV, 2 hours data

**YELLOW mode**

**BLUE mode**

- BPM at IR12 reading:
- Blue (x,y)= (+5, +8)mm
- Yellow (x,y) = (0, 4)mm,  Fill#9920

- BPM at IR12 reading:
- Blue (x,y)= (0, 4)mm
- Yellow (x,y) = (10, +10)mm, Fill#9905

## pC: Online vs “fast offline”

**pC: Online vs “fast offline”**

- Yellow online polarizations look unbiased compared to online

- Blue online polarizations are overestimated compared to online by ~4% relative

- Absolute scale in not yet fixed

## pC stability: “Dead Layer”

## pC stability: T0