# Presentation: 713693

## Chiral odd fragmentation function

**at Belle**

_**Ogawa Akio**_
- Penn State Univ. / BNL / RBRC
- 2002 April 3
- QCD-N 02
- At Ferrara

## Slide 2

## “Complete” Transversity Measurements

- Polarized pp  -    RHIC Star/Phenix/Phobos (BNL)

- Polarized DIS  -  Hermes(DESY) Compass(CERN)  eRHIC  Tesla-N

- e+e- collider    -     Belle (KEK)  Babar  LEP ...

- Tensor Charge     Lattice calculations  - RBRC ....

- S. Aoki, M. Doui, T. Hatsuda and Y. Kuramashi  Phys.Rev. D56 (1997)433
- More recently: S. Capitani et.al. Nucl. Phys. B (Proc. Suppl.) 79 (1999) 548

## Belle experiment at KEK

- The world best statistics
- Hermetic detector
- Excellent PID upto top energy
- High enough energy
-                            s~100GeV2
- Not too high energy
-      - No extra complication
-        due to Z pole
-      - FF evolves down as energy
-        goes up
- RBRC group have joined the Belle
-             M.G-Perdekamp, S. Lange, A.Ogawa, K. Hatsuko & V. Siegle

## KEKB-Belle Luminosity

- Peak Luminosity
-       7.249 1033/cm/cm/s
-          World Record!
- Design Luminosity
-       10.0 1033/cm/cm/s
- (Babar =  3.3 1033/cm/cm/s)

**    ****shift = **** 128.8 /pb **
**      ****day = **** 358.7 /pb **
**      ****24h = **** 363.7 /pb **
**    ****7days = ****2207.  /pb **
**    ****month = ****7241.  /pb **

- Totoal Integrated Luminosity
- ~64.5 / fb           (10% off resonance)
- >108 Events on tape

## Belle Detector

## Example hadronic events

## Heppelmann-Collins Fragmentation Function

- Z = Eh / Eq
- angle between S and kT  around quark (jet) axis

- A =

- s

- q

- s

- kT

- h

- kT

- h

- q

- q

- s

- h

## 2 pion interference fragmentation function :

- Zpair = (E+ +E- ) / Eq
- m =  invariant mass of 2 pions
- angle between s and r

- s

- q

- q

- s

- A =

- r

- r

- q

- s

- The same thing for KK around 

## jet1

- jet2

- Without
-   using
-  jet axis

- Spin of quarks are
-      correlated!

- n

- n

- Gluon emission can
- cause same sin(2)
-    But calculable

## jet1

- jet2

- Spin of quarks
- are correlated!

- n

- Gluon emission does NOT fake this asymmetry

## A first look at off-resonance data & MC

- d  s   b

- u    c

- e  

- # of pion

- Enough multiplicity to see
-         4 particle correlations
- We can see 2 “Jet” events
- Estimates of statistics as function of z
- Heavy flavors(mostly charm) rejection
- We first look at off-resonance data
- Tau production for x-check

- Just started a month ago, after 1st RHIC polarized spin run

- R2

- E_pion

- Thrust

## Conclusion

-  Collins FF and Interference FF  are needed
-  to extract transversity from DIS/pp
-  to understand AN for inclusive pion productions
-  FF itself  is as fundamental as PDF
-  e+e- can measure these FF
- B factories are the places to measure it
- Luminosity, detector with PID, energy, etc
- Comparison with LEP data will be interesting
-  RBRC group (Matthias & myself & some more) have joined Belle
-  RHIC Spinners on the task, and more people will join!
-  Theory tasks!

## Statistics estimate 

- CC	0-0.2	0.2-0.4   0.4-0.6  0.6-0.8   0.8-1.0  (z1)
- 0-0.2 	0.00031  0.00068  0.0014   0.0032   0.0072
- 0.2-0.4	0.00068  0.0015    0.0031   0.0070   0.016
- 0.4-0.6	0.0014    0.0030    0.0063   0.014     0.032
- 0.6-0.8	0.0032    0.0070    0.014     0.033     0.073
- 0.8-1.0	0.0072    0.016      0.032     0.073     0.16
- Cq
- 0-0.2 	0.0014   0.00063   0.0012    0.0027   0.0060
- 0.2-0.4 	0.0029   0.0014     0.0027    0.0058   0.013
- 0.4-0.6 	0.0061   0.0028     0.0055    0.012     0.027
- 0.6-0.8 	0.014     0.0064     0.013      0.027     0.062
- 0.8-1.0 	0.030     0.014       0.028      0.061     0.14
- qq
- 0-0.2 	0.0058   0.0027    0.0053   0.012      0.026
- 0.2-0.4 	0.0027   0.0013    0.0025   0.0053    0.012
- 0.4-0.6 	0.0053   0.0025    0.0048   0.010      0.024
- 0.6-0.8 	0.012     0.0053    0.010     0.023      0.051
- 0.8-1.0 	0.026     0.012      0.024     0.051      0.12
- (Z2)

- Estimate of
-   F*F) = /cos()
- For ~2.3/fb ~ 6M Events
- Belle already have 3 times more
- Off-resonance data, and 30 times
- more On-resonance. And more
- will come!
- For example:
-    2pions + 2 pions
-  	4 C*C
-  	4 C*q
- 	1 q*q
- total 9 independent
-    measurements
-    in a event

## STAR Forward Pion Detector

- Top

- Bottom

- South

- North

- 7m

- 7.5m

- FPD

- STAR Mid Rapidity
- Detector

- XF ~ 0.1 to 0.6 or -0.1 to -0.6
- pT ~ 1 to 4 GeV
- E ~ 10 to 60 GeV

**Online Results  : **
- 0 reconstruction
-    up to 60 GeV
- as a probe for possible
- AN 0 measurements
-    @ s = 200GeV

- Preliminary

- 2 photon
- detected at
- Shower Max
- Detector
- Energy
- measured
- in EMC