# Presentation: 582629

## Highlights from the spin PWG

- Kensuke Okada (RBRC)
- for the spin PWG
- PHENIX collaboration meeting
- July 18, 2008

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

## Topics covered by the SpinPWG

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

**What is the spin structure of proton?**

**Longitudinal spin structure**

**Gluon polarization**
**(Anti-)quark flavor decomposition**

**Transverse spin structure**

**Transversity**
**Orbital angular momentum**

**Method**

**The basic idea : **
**     ****To see the spin effect, measure the difference between spin orientations.**

- A_LL, A_L, A_TT, A_N, ...
- D_LL, D_LS, ...

## PHENIX datasets

| Year | s [GeV] | Recorded L | Pol [%] | FOM (P4L) |
| --- | --- | --- | --- | --- |
| 2003 (Run 3)  | 200 | .35 pb-1 | 27 | 1.9 nb-1 |
| 2004 (Run 4) | 200 | .12 pb-1 | 40 | 3.1 nb-1 |
| 2005 (Run 5) | 200 | 3.4 pb-1 | 49 | 200 nb-1 |
| 2006 (Run 6) | 200 | 7.5 pb-1 | 57 | 790 nb-1 |
| 2006 (Run 6) | 62.4 | .08 pb-1 ** | 48 | 4.2 nb-1 ** |

- Longitudinally Polarized Runs

- ** initial estimate

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

**The program for gluon polarization (********g) **

**No data since Run6....**

- (With the rotator on)

**Notes:**
From Ken’s talk at Spin Praha, add run8

## PHENIX datasets

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

- Transversely Polarized Runs

| Year | s [GeV] | Recorded L | Pol [%] | FOM (P2L) |
| --- | --- | --- | --- | --- |
| 2001 (Run 2) | 200 | .15 pb-1 | 15 | 3.4 nb-1 |
| 2005 (Run 5) | 200 | .16 pb-1 | 47 | 38 nb-1 |
| 2006 (Run 6) | 200 | 2.7 pb-1 | 57 | 880 nb-1 |
| 2006 (Run 6) | 62.4 | .02 pb-1 ** | 48 | 4.6 nb-1 ** |
| 2008 (Run8) | 200 | 5.2 pb-1 ** | 45 | 1100 nb-1 ** |

- ** initial estimate

**The program for transversity and orbital angular momentum.**

- Vertically polarized (the natural direction)

- Radially polarized (with the rotator on)

## Published results

- PHENIX Collaboration meeting urbana,IL

- ppg31
- PRL(2004)
- Run3

- ppg59
- PRD(2006)
- Run3+4

- ppg63
- PRD(2007)
- Run5

- ppg50
- PRL(2005)
- Run2

******0**** A****LL**

**A****N**** **
**(central arm)**

******G is small!**

**A****N**** is small!**

**And **
**p+p cross section papers, **
**with other PWGs.**

## (proto) ppgs

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

**ppg87 (K. Aoki)  **0 ALL at s=62.4GeV : The xg range is different.
**ppg89 (D. Fields) **kT asymmetry in Double-longitudinally polarized p+p : jet correlation
**ppg91 (K. Boyle) **0 ALL at s=200GeV from Run6

**Proto-ppg**

**ppg**

**Multi-particle A****LL**** (K. Nakano) : “jet” analysis **
**A****LL**** of eta (F. Ellinghaus) : **
**Forward neutron cross section and A****N**** (M. Togawa) : neutrons are tagged by ZDC.**

- ppg89

- Forward neutron

## Preliminaries

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

- 2008. 7

- (**Run5,6) Prompt mu A_LL, A_L **
**(Run3) Anti-Lambda (D_LL), D_LS, A_LL**

- 2008.6

**(Run6) IFF**

- 2008.5

**(Run6) Prompt mu A_N**

- 2008.3

**(Run6) Direct-gamma 62.4GeV (H/P)**
**(Run6) Charged pi A_LL**

- 2007.12

**(Run6) Eta A_LL**

- 2007.11

**(Run3) anti-Lambda D_LL**
**(Run5) single-e A_LL**

- 2007.10

**(Run5) direct photon A_LL**

- 2007.7

**(Run5) eta (H/P)**

- 2007.6

**(Run6) pi0 A_LL **

- 2007.5

**(Run6) pi0 62.4GeV (H/P) **
**(Run6) MPC pi0 62.4GeV A_N**

**The list is from the last year.**
**The current status is **

**ppg or proto-ppg,**
**Active,**
**Not active**

## Ongoing analysis

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

**From PWG presentations the last year (before preliminary),**

**Run6 Central arm Sivers (Feng) : **
-                     a jet correlation analysis from the transversely polarized data.
**Run6 Dimuon A****TT**** (Todd) : **
-                     towards the asymmetry of DY process. A direct access to the transversity.
**Charged pion cross section study (Astrid): **
-                     It supports the ALL result.
**Access to low-x region with di-hadron using MPC (John):**
-                     A way from inclusive to exclusive probes
**Electron (Central arm) and muon (muon arm) correlation study (Mikhail): **
-                     An idea to enhance the charm sample.

**Anything comes with the spin orientation must be related to **
**the spin structure of the proton.**
**But what kind of probe is appropriate?**

**???**

## Key points

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

**Basic data for the asymmetry measurement**

**The understanding of spin averaged object**

**Polarization of protons : Both absolute value and direction**
**Relative luminosity : It should be measured by a spin unbiased probe.**
**                                     ****For the single azimuthal asymmetry, it can be bypassed.**

**Statistics and the signal to background ratio**

**The asymmetry signal is so tiny!**

**It needs to be collaborated with other PWGs.**
**Sometimes it is not very clear.**

## Fight for S/B

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

**Prompt muon**

**Prompt photon **
**(with an isolation cut)**

- (1-r)

**The ideal case : We know B exactly (********B****=0)**

**S/B is as important as **
**the integrated luminosity. **

**r**

## The understanding of spin averaged object

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

**(It’s an issue, especially when we see no asymmetry.)**
**Be as simple as possible!**

**Multi-particles**

**Partial jet caught in PHENIX**
**2 (or more) fragmentation function**

**Charm, J/psi **

**How to connect the observables to the proton components?**
**What is the production mechanism?**

**kT asymmetry of longitudinally polarized protons  (related to ppg89)**

**Is there centrality class in proton-proton collisions?**

**Hard/soft separation**

**The factorization scheme doesn’t work in the soft process.**

## The future

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

## Integrated L goals:

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

- From RHIC Spin Plan Report  (June 9,2008)

**Delivered ********L**
**Recorded  ~0.35X**

**Notes:**
Run9 *1.3 with a new 9MHz RF.
In addition *2 with 200MHz strage system. 
Run8 : 7.5/pb/week
Run9 : 14.5
Run10 : 21.6 

## Global fit with RHIC + DISde Florian, Sassot, Stratmann, Vogelsang, arXiv:0804.0422

**Now**

**50 pb****-1**

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

## W physics in s=500 GeV

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

**W -> e (central arm)**
**W -> mu (muon arm)**

**The parity violating process is to decompose the anti-quark flavor.**

**Observables :   A****L**** of electrons and muons from the W decay. **

**The MC estimations need to be confirmed by the real data. **

**How much is the QCD backgrounds?**
**Is the momentum resolution enough?**

## Beyond Run9

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

**VTX, FVTX, NCC, W-trigger**

**The detector upgrades**

**Drell-Yan transverse single spin asymmetry**

**Check fundamental QCD prediction of sign change in Sivers asymmetry **
**between Drell-Yan and semi-inclusive DIS**

**Heavy flavor tagging**
**Increase the acceptance ******** It helps determination of the kinematics**

## Outlook

| Recorded 
Luminosity  | Main physics Objective | Remarks |
| --- | --- | --- |
| ~50pb-1 | Gluon polarization using di-jets and precision inclusive measurements | 200 GeV |
| ~100pb-1 | W production (Important consistency check to DIS results - Phase I)
Gluon polarization (Di-Jets / Photon-Jets) | 500 GeV |
| ~300pb-1 | W production (Constrain antiquark polarization - Phase II)
Gluon polarization (Di-Jets / Photon-Jets) | 500 GeV |
| ~30pb-1 | Transverse spin gamma-jet  | 200 GeV |
| ~250pb-1 | Transverse spin Drell-Yan (Long term)  | 200 GeV |

**P=.7; **_**running time is critical**_**.**

- (BNL PAC talk  May 2008)

## Spinfests

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

**2005 at RIKEN (July 11- September 2)**
**2006 at BNL (July  24 – September 1)**
**    ****2007 at BNL (March 19 – April 6) (analysis only)**
**2007 at RIKEN (June 11 – July 27)**
**2008 at BNL (July 21 – August 8) **
**2009 in Hawaii? **

**Goals**

- Sponsored by RIKEN, LANL

## Summary

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

-   **Inclusive ********0**** has been the only probe of the gluon polarization published for now. **
**  ****As the integrated luminosity is increased, other inclusive probes (********±****, direct photon, **
**heavy quarks) get to be in the scope. In addition, di-jet (di-hadron) analysis **
**determines the kinematics. And the jet correlation itself can be a spin probe. **

**   ****The field of transverse spin physics is still developing rapidly.  **
**A number of  inclusive A****N ****analyses from Runs 6 and 8 still need **
**people to work on them!  **

**  ****We need 30 times more integrated luminosity in ********s=200GeV to meet **
**the original plan. (The A****LL**** of direct photon )**
** ****Another program with ********s=500GeV is also exciting. **

**The spinPWG is actively working on Run5,6,8 data.**

## BACKUP SLIDES

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

## Published results

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

- Double Helicity Asymmetry in Inclusive Mid-Rapidity neutral pion
- Production for Polarized p+p Collisions at sqrt(s)=200 GeV

- ppg31

- Phys. Rev. Lett. 93, 202002 (2004)

- ppg50

- Measurement of Transverse Single-Spin Asymmetries for Mid-rapidity
- Production of Neutral Pions and Charged Hadrons in Polarized p+p
- Collisions at sqrt(s) = 200 GeV

- Phys. Rev. Lett. 95, 202001 (2005)

- An Update on the Double Helicity Asymmetry in Inclusive Midrapidity
- $\pi^{0}$ Production for Polarized $p+p$ Collisions at $\sqrt{s}=200$ GeV

- ppg59

- Phys. Rev. D 73, 091102(R) (2006)

- Inclusive cross section and double helicity asymmetry for pi^0 production
- in p+p collisions at sqrt(s)=200 GeV:
- Implications for the polarized gluon distribution in the proton

- ppg63

- Phys. Rev. D 76, 051106 (2007)

- Run3 pi0 A_LL

- Run3 pi0, h A_N

- pi0 A_LL, update (Run3+Run4)

- pi0 A_LL, update chi2 (Run5)

## (proto) ppgs

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

| 2008b | Spin | M.Togawa;G. Bunce, S.White,Y.Goto,K.Tanida |   |   |   |   |   | 84 | 18-Apr-08 | 2008b | 5 | p+p | 200 GeV | A_N | forward neutron x-sect and A_N; M.Togawa |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 2007l | Spin | F. Ellinghaus; J.Seele,E.Kinney,C.Aidala |   |   |   |   |   | 210 | 14-Dec-07 | 2007l | 5,6 | p+p | 200 GeV | A_LL,eta | x-sect, A_LL eta, comp.to pi^0; F. Ellinghaus |
| 2007k | Spin | K.Nakano;Y.Akiba,Y.Goto,J.Lajoie,T.-A.Shibata |   |   |   |   |   | 302 | 13-Sep-07 | 2007k | 6 | p+p | 200 GeV | A_LL | Event structure&A_Ll in part. cluster; K.Nakano |
| 2007i | Spin | K.Boyle; A. Bazilevsky, G. Bunce, A. Deshpande |   |   |   |   |   | 332 | 14-Aug-07 | 2007i | 6 | p+p | 200 GeV | A_LL,pi^0 | delta G from pi^0 A_LL; K. Boyle |
| 089 | Spin | hep-ex |   | wrk |   | PRL | PPG formed | 4 | 7-Jul-08 | 2007g | 5 | p+p | 200 GeV | di_h,crl | k_T asymmetry di-h correl.long.pol.;Doug Fields |
| PPG # | PWG | arXiv | IRC formed | w/us | w/jrn | jrn. | last action | days | last act'n | PPG # | Run(s) | CollSys | sqrt(sNN) |   | Description and PPG Head Name |
| 087prd | Spin | hep-ex | 2-Jun-08 | int1 |   | prdR | first int. revue | 56 | 16-May-08 | 087prd | 6 | p+p | 62.4 GeV | A_LL,pi^0 | pi^0 incl. X-sect & A_LL; K. Aoki |

## Preliminaries

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

- 2008. 7

- (Run5,6) Prompt mu A_LL, A_L
- (Run3) Anti-Lambda (D_LL), D_LS, A_LL

- 2008.6

- (Run6) IFF

- 2008.5

- (Run6) Prompt mu A_N

- 2008.3

- (Run6) Direct-gamma 62.4GeV (H/P)
- (Run6) Charged pi A_LL

- 2007.12

- (Run6) Eta A_LL

- 2007.11

- (Run3) anti-Lambda D_LL
- (Run5) single-e A_LL

- 2007.10

- (Run5) direct photon A_LL

- 2007.7

- (Run5) eta (H/P)

- 2007.6

- (Run6) pi0 A_LL

- 2007.5

- (Run6) pi0 62.4GeV (H/P)
- (Run6) MPC pi0 62.4GeV A_N

## Recent activities

- 7/18/2008

- PHENIX Collaboration meeting urbana,IL

- June 2007 ~ July 2008
- Presentations at SpinPWG