Summary of theSpin Physics session

-- experimental part --

Delia Hasch

(spin) structure of the (spin) structure of the nucleonnucleon

K. KrysztofA. KorzenevL. De NardoK. GriffionP. ColeK. Slifer

@6GeV

“You think you understand something? Now add spin…” -- R. Jaffe

polarised structure polarised structure functions: gfunctions: g11

proton, deuteron neutron[L. De Nardo]

[L. De Nardo K. Krysztof]

polarised structure polarised structure functions: gfunctions: g11

Q2>1GeV2

(theory) (exp) (evol) = 0.330 ± 0.011 ± 0.025 ± 0.028

a0=MS

a0=

= 0.35 ± 0.03(stat) ± 0.05(sys+evol)

MS

@Q2=5GeV2

@Q2=3GeV2

helicity distributionshelicity distributionsvalence quark distributions: uvdv

from semi-inclusive difference asymmetry:)(d)(u

)(d)(u)(A

vv

vvhhd xx

xxx

first SIDIS result from COMPASS!

[A. Korzenev]

spin structurespin structure

EG1/4/12 @CLAS

• resonance region • GDH SR

Q2 (GeV2)0Q2 • study of high x• prove of duality• determination of HT …

[K. Griffion, K. Slifer]

(spin) structure of the (spin) structure of the nucleonnucleon

P. Liebing

S. Koblitz

K. Okada

R. Fatemi

F. Simon

J. Lajoie

-0.1

0

0.1

0.2

0.3

0.001 0.01 0.1 1

AAC06

GRSV

BB

LSS

-0.6-0.4-0.2

00.20.40.60.8

11.21.4

0.001 0.01 0.1 1

x

xg(x)

Q2 = 1 GeV2

x(x)

AACBB

GRSV

LSS

gluon polarisation gluon polarisation

from scaling violation:

gluon polarisation gluon polarisation “direct” measurements:

Photon-Gluon Fusion (PGF)

• golden channel: charm productiongolden channel: charm production

• hadron production at high Phadron production at high PTT

[P. Liebing, S. Koblitz]

gluon polarisation gluon polarisation “direct” measurements: polarised pp @RHIC :

gluon polarisation gluon polarisation “direct” measurements: polarised pp @RHIC :

2005 data

ALL for , , J/

[K. Okada, R. Fatemi, F. Simon]

Di-jets: directly xg

gluon polarisation gluon polarisation “direct” measurements: polarised pp @RHIC FUTURE:

2006: 7.5 pb-1 @60% polarisation

projections

upgrade programme

[K. Okada, R. Fatemi, F. Simon, J. Lajoie]

(spin) structure of the (spin) structure of the nucleonnucleon

R. Seidl

M. Diefenthaler

A. Bressan

U. D’Alesio

O. Eyser

S. Heppelmann

J. Lee

J. Balitsky

C. Schill

A.Kotzinian

transversity&friendstransversity&friends

first glimpsefirst glimpse of transversity of transversity global fit of data from BELLE(FF ), HERMES and COMPASS(DFxFF )

e-

e+

Collins fragmentation function AUT sin(s)

global fit of data from BELLE(FF ), HERMES and COMPASS(DFxFF )

Collins fragmentation function

first glimpsefirst glimpse of transversity of transversity

[U. D’Alesio]

new data:

global fit of data from BELLE(FF ), HERMES and COMPASS(DFxFF )

29 fb-1 547 fb-1

full data set with transv. target:

,K

,K

first glimpsefirst glimpse of transversity of transversity

[U. D’Alesio]

[R. Seidl, M. Diefenthaler, A. Bressan]

full data set

transversitytransversity

[M. Diefenthaler, A. Bressan]

Sivers Sivers

implies non-zero Lq

[M. Diefenthaler, A. Bressan]

leftright

transversity&friends transversity&friends @@RHIC RHIC

Xhpp

• K ,p,p-bar

0

2006: P~60%

[J. Lee, O. Eyser, S. Heppelmann, J. Balewski]

leftright

transversity&friends transversity&friends @@RHIC RHIC

Xhpp

• K ,p,p-bar

0

2006: P~60%• jet back-to-back correlations Sivers• two hadron correlation transversity …

[J. Lee, O. Eyser, S. Heppelmann, J. Balewski]

(spin) structure of the (spin) structure of the nucleonnucleon

H. Guler

A. Rostomyan

A. Mussgiller

E. Voutier

J. Pierce

HallA, CLAS

hunting for Lhunting for Lqq

10-30%(DIS)10-30%(DIS)

( H + E) x dx = JJqq

= = 1/2 1/2 LLzz

Q2

t

Generalised Parton Distributions

hard exclusive processes:

Q2>>, t<<

e+/- p → e+/- p X<1.7 GeVin HERMES acceptance

Regge, D-term

Regge, no D-term

fac., D-termfac., no D-term

γpepe ''/-

DVCSDVCS beam beam chargecharge asymmetry asymmetry

[PRD75(2007)]

20xmore e statistics on tape from 2005/06

1998 e

data set10 pb-1

[A. Mussgiller]

hunting for Lhunting for Lqq GPD: E GPD: Eobservables:

AUT 0

DVCS

DVCS cross section on neutron

HallA

hunting for Lhunting for Lqq GPD: E GPD: E

AUT

0L

[A. Rostomyan, A. Mussgiller, E. Voutier]

x

DVCS

t (GeV2) x Q2 (GeV2)

xB=0.36, Q2=1.91 GeV2

HallA

hunting for Lhunting for Lqq

model dependent constraint of Ju vs Jd

[A. Mussgiller, E. Voutier]

much more much more polarisation observables polarisation observables

• transverse polarisation

• determining the spin structure of resonances• transverse spin of the pion• hydrogen hyperfine splitting …

[Y. Naryshkin, P. Cole, J. Pierce]

spin physics is a very active spin physics is a very active fieldfield

thanks to all the participants of the Spin Session for this fruitful meeting

Daniel, Gerhard & Delia

[apologises to all speakers not covered in this summary]