# Presentation: 113033

## PHENIX Muon Trigger Upgrade for the Study of Quark Contribution to Proton Spin Structure

- Wei Xie *(Riken-BNL Research Center)*
*for* PHENIX Collaboration

- 21st Winter's Workshop at Brekenridge

- 2/11/2005

## Proton Spin Structure 

- Naive parton model: valance quark are responsible for proton spin

- QCD: sea quark and gluons. Parton orbital angler momentum also contribute .

- Proton spin:
- 1⁄2 = 1⁄2 (quark)+ G(gluon) + Lz

- f(x) = f(x) – f(x),  where f(x) and f(x) are PDF with spin parallel and anti-parallel to the proton spin.

-  (EMC: Spin crisis)

- 21st Winter's Workshop at Brekenridge

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## Current Measurement on Quark and Gluon spin

- SLAC: E80, E130, E142, E143, E154, E155 (1978-2001)
- CERN: EMC, SMC, COMPASS (1988-2004)
- DESY: HERMES (1995-2004)

- Quark spin :    	well constrained
**Sea Quark spin:****	****large uncertainty**
- Gluon spin:	Unknown

- 21st Winter's Workshop at Brekenridge

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## Spin of Different Flavor of Quarks has been Measured

-  Q2 is low
-  “Hadron taging” technique relies on knowledge of fragmentation functions

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## How PHENIX Measure Quark Spin

- W is produced through V-A process,  helicity of quark is fixed:

- 21st Winter's Workshop at Brekenridge

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## Expected PHENIX Measurement

- Annu. Rev. Nucl. Part. Sci.2000.50:525-75

**a.u.**

- 21st Winter's Workshop at Brekenridge

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## Single Muon Trigger Need Upgrade

-  W sample: ~104 for the 800pb-1 luminosity.
-  can’t be pre-scaled!
- collision rates in 500GeV run:  ~12MHz,.
-  trigger rate w/ perfect background shielding: ~24KHz
-  trigger rate w/o background shielding  ~50KHz
- PHENIX bandwidth: 12KHz(or 24KHz with additional $2M)
*1-2kHz assigned to W trigger*
- need additional rejection of 20-50, i.e. above 10000 rejection faactor

**Single Muon Trigger Need Upgrade**

- 21st Winter's Workshop at Brekenridge

- 2/11/2005

##    Ideas for trigger upgrade

- Hodoscope I

- Cerenkov

- Hodoscope II

**   ****Ideas for trigger upgrade**

- Pad Chamber II

- MuTr#1

- Nosecone calorimeter

- Pad Chamber I

- MuID road

- MuTr#2

- MuTr#3

- PHENIX magnetic field

- 21st Winter's Workshop at Brekenridge

- 2/11/2005

## Option I:  pad chamber solution

******(********)=angle I – angle II: momentum cut**

**Option I:  pad chamber solution**

- Enough rejection power with good efficiency for high pT muons

| deg | <0.7 | <1.0 | <2.0 |
| --- | --- | --- | --- |
| rejection | 36000 | 19980 | 10090 |

- 21st Winter's Workshop at Brekenridge

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## -

- -

- +

|  | Sagitta<=1 strip | Sagitta<=2 strips | Sagitta<=3 strips |
| --- | --- | --- | --- |
| Rej | 23700 | 10900 | 7180 |

*Result from Kazuya Aoki*

- A birds eye view

**Option II:  MuTr Solution**

- Enough rejection power with good efficiency for high pT muons

- 21st Winter's Workshop at Brekenridge

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## Ongoing R&D Effort

- Measurement of background in central and forward region using scintilliator has been successfully done by RBRC and UIUC.

-  Outgoing beam background (attenuated by PHENIX absorber)

-  Incoming beam background (un-attenuated)

-  Neutron background which is out of time.

- 3 background components:

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##  Plan to use CMS RPC technology

- RPC test bench was setup at UIUC.
- RPC prototype test during RUN5  p-p run by UIUC, RBRC and PKU
-  A byproduct: Relative-luminosity monitor.

**Chamber technology:**    *Good position and time resolution and cheap price*

- 21st Winter's Workshop at Brekenridge

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## R&D on fast readout FEE is ongoing at Kyoto University.

-  have built a test MuTr#1 chamber with the help of UMN
-  plan to have the final design in 2005 and mass production in 2006.

- MuTr test chamber at Kyoto.

- 21st Winter's Workshop at Brekenridge

- 2/11/2005

## Possible Configuration

-  pad chamber solution only
-  Downstream hybrid trigger
-  rebuilt MuTr electronics i.e. MuTr LL1
-  combination of the two method
-  nosecone calorimeter (*Vasily’s NCC talk*)

- MuTr#1

- Nosecone calorimeter

- MuTr#2

- MuTr#3

- MuID

- 21st Winter's Workshop at Brekenridge

- 2/11/2005

## University of Colorado
Frank Ellinghaus, Ed Kinney, Jamie Nagle, Joseph Seele, Matt Wysocki
University of California at Riverside
Ken Barish, Stefan Bathe, Tim Hester, Xinhua Li, Astrid Morreale, Richard Seto, Alexander Solin
University of Illinois at Urbana Champaign
Mickey Chiu, Matthias Grosse Perdekamp, Hiro Hiejima, Alexander Linden-Levy, Cody McCain, 
Jen-Chieh Peng, Joshua Rubin, Ralf Seidel
Iowa State University
John Lajoie, John Hill, Gary Sleege
Kyoto University
Kazuya Aoki, Ken-ichi Imai, Naohito Saito, Kohei Shoji
Columbia University
Cheng Yi Chi, William Zajc
University of New Mexico
Doug Fields
RBRC
Gerry Bunce, Wei Xie
Abilene Christian University
Rusty Towell, Larry Isenhower
Peking University
Yajun Mao, Ran Han, Hongxue Ye, Hongtao Liu

- Frank Ellinghaus, Ed Kinney, Jamie Nagle, Joseph Seele, Matt Wysocki
**University of California at Riverside**
- Ken Barish, Stefan Bathe, Tim Hester, Xinhua Li, Astrid Morreale, Richard Seto, Alexander Solin
**University of Illinois at Urbana Champaign**
- Mickey Chiu, Matthias Grosse Perdekamp, Hiro Hiejima, Alexander Linden-Levy, Cody McCain,
- Jen-Chieh Peng, Joshua Rubin, Ralf Seidel
**Iowa State University**
- John Lajoie, John Hill, Gary Sleege
**Kyoto University**
- Kazuya Aoki, Ken-ichi Imai, Naohito Saito, Kohei Shoji
**Columbia University**
- Cheng Yi Chi, William Zajc
**University of New Mexico**
- Doug Fields
**RBRC**
- Gerry Bunce, Wei Xie
**Abilene Christian University**
- Rusty Towell, Larry Isenhower
**Peking University**
- Yajun Mao, Ran Han, Hongxue Ye, Hongtao Liu

- Who is proposing?

- 21st Winter's Workshop at Brekenridge

- 2/11/2005

## backup

- 21st Winter's Workshop at Brekenridge

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## An Alternative Way to Measure Quark Spin

**A****L****(W****+****)**

**A****L****(W****+and ****W****-****)**

**p****T****(muon)**

**p****T****(muon)**

- Resummation Method:
- first principles calculation by Nadolsky and Yuan at NLO pQCD (Nucl. Phys.B 666(2003) 31).

- When there’s no charge sign identification

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## Study Spin Structure in Deep Inelastic Scattering 

- LO picture:

- Experimental measurement:

- 21st Winter's Workshop at Brekenridge

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## Current DIS experiment for G measurement through hadron pair production

- Contributions to the asymmetry measurement

- Relative low Q^2 and need long running time.

- 21st Winter's Workshop at Brekenridge

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## Study Spin Structure in polarized p-p collision

- Many different channel to measure G, e.g. prompt photon production:

- Solid theoretical support:

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## Past DIS experiment

- 21st Winter's Workshop at Brekenridge

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