Delia Hasch

Delia HaschDelia Hasch

TMDs & friends from lepton TMDs & friends from lepton

scatteringscattering-experimental overview--experimental overview-

INT workshop on “3D parton structure of the nucleon encoded in GPDs & TMDs”,INT workshop on “3D parton structure of the nucleon encoded in GPDs & TMDs”, Seattle, Sept. 14-18 2009Seattle, Sept. 14-18 2009

outline:• introduction: some reminders…

• status Sivers DF

Collins DF

• azimuthal dependence of unpolarised xsection

• the ‘soon to come’ menu

experimental prerequisites experimental prerequisites

190 GeV

≈6 GeV e

27 GeV e

till 2007

HALL AHALL A

• longitudinally polarised d• long.+transv. polarised p• ~full hadron ID

CLAS: long. polarised effective p HallA: long.+transv. polarised effective n

main players in the game:

• long.+transv. polarised effective d• long.+transv. polarised effective p• ~full hadron ID

1/7/07@ 1:09:56 am

deep-inelastic scatteringdeep-inelastic scatteringQ2 factorisation:

)(ˆh xpdfpartfDIS )(hgq, zfrag

1 GeV2

hadron production hadron production @@RHIC RHIC 0 and jet production xsection vs pT compared to theory

hadron production hadron production no SIDIS xsection measurements @HERMES and CLAS pion multiplicities

[deFlorian,Sassot,Stratmann arXiv:0708.0769]

compared to theory:

DSS: fragmentation

functions from

combined NLO analysis

of single-inclusive

hadron production in

e+e-, pp and SIDIS

hadron production hadron production no SIDIS xsection measurements @HERMES and CLAS pion multiplicities

CLAS 0 compared to HERMES and to DSS:

SIDIS cross sectionSIDIS cross section)(ˆh

XY xpdfpartf )(hgq, zfrag

XY

beam: target: SL ,ST

SIDIS cross sectionSIDIS cross section)(ˆh

XY xpdfpartf )(hgq, zfrag

leading-tw distribution functions leading-tw distribution functions partf

ˆhXY )(xpdf )(hgq, zfrag

chiral-odd

pdf & FF

‘Amsterdam notation’

leading-tw distribution functions leading-tw distribution functions partf

ˆhXY )(xpdf )(hgq, zfrag

on the menutoday

@leading twist, integrated over pT:

leading-tw distribution functions leading-tw distribution functions

‘transversity’

leading-tw distribution functions leading-tw distribution functions

@leading twist, no pT integration:

‘transversity’

‘Kotzinian-Mulders’

‘pretzelosity’

‘Boer-Mulders’

‘Sivers’

asymmetries and amplitudesasymmetries and amplitudes

...cos1

2cos UUUUUU dQ

ddd

+ …

UTsUTsUTs ddd )3sin()sin(){sin(ST

}sinQ

1)2sin(

Q

1sUTs d

asymmetries and amplitudesasymmetries and amplitudes

...cos1

2cos UUUUUU dQ

ddd

taking also into account of the unpolarised cross section

UUUU)2cos()cos(

UTsUTsUTs ddd )3sin()sin(){sin(ST

}sinQ

1)2sin(

Q

1sUTs d

)3sin()3()sin()2()sin()1(),( SSSSfitUT PPPA

SS PP sin)5()2sin()4(

Collins momentSivers moment

spin-orbit correlationsspin-orbit correlations

Sivers function:

[Matthias Burkardt]

a non-zero Sivers fct. requires non-zero orbital angular momentum !

Sivers Sivers amplitudesamplitudes

)(),( 1T1 zDkxf qT

q )(),( 1T1 zDkxf qT

q

ep hX [PRL94(2005)]

first observation of T-odd Sivers effect in SIDIS

u quark dominance suggests sizable u quark orbital motion

Sivers Sivers amplitudesamplitudes

)(),( 1T1 zDkxf qT

q )(),( 1T1 zDkxf qT

q ep hX

first observation of T-odd Sivers effect in SIDIS

u quark dominance suggests sizable u quark orbital motion

[arXiv:0906.3918]

Sivers Sivers amplitudesamplitudes forfor

[arXiv:0906.3918]

clear rise with z

)()(e

),(),(e)sin(2

12

21

2,1T

2

zDxf

kzDpxfqq

q q

Tq

Tq

q q

UTS

)()(e

),(),(e)sin(2

12

21

2,1T

2

zDxf

kzDpxfqq

q q

Tq

Tq

q q

UTS

rise at low Ph

plateau at high Ph

T

T dominated by u-quarks

u-quark Sivers DF < 0


[arXiv:0906.3918]

clear rise with z

)()(e

),(),(e)sin(2

12

21

2,1T

2

zDxf

kzDpxfqq

q q

Tq

Tq

q q

UTS

)()(e

),(),(e)sin(2

12

21

2,1T

2

zDxf

kzDpxfqq

q q

Tq

Tq

q q

UTS

rise at low Ph

T

plateau at high Ph



cancellation for :

u and d quark Sivers DF

of opposite sign


[arXiv:0906.3918]

clear rise with z

)()(e

),(),(e)sin(2

12

21

2,1T

2

zDxf

kzDpxfqq

q q

Tq

Tq

q q

UTS

)()(e

),(),(e)sin(2

12

21

2,1T

2

zDxf

kzDpxfqq

q q

Tq

Tq

q q

UTS

rise at low Ph

plateau at high Ph

T



cancellation for :

u and d quark Sivers DF

of opposite sign all asymmetries on deuterium target ≈ zero!

[PLB673(2009)]


[arXiv:0906.3918]

)()(e

),(),(e)sin(2

12

21

2,1T

2

zDxf

kzDpxfqq

q q

Tq

Tq

q q

UTS

)()(e

),(),(e)sin(2

12

21

2,1T

2

zDxf

kzDpxfqq

q q

Tq

Tq

q q

UTS

proton data

?

Sivers Sivers distribution for valence distribution for valence quarksquarks transverse SSA of pion cross section difference:

Sivers distribution for

u-valence is large &

<0

or Sivers distr. for d- valence >> u-valence(unlikely)

vv

vv

d1

u1

d,1T

u,1T

S 4

4)-sin(

ff

ffUT

Sivers: Sivers: kaon amplitudeskaon amplitudes

ep KX

clear rise with z

rise at low Ph

T

plateau at high Ph

T

slightly positive

Sivers: Sivers: the “kaon challenge” the “kaon challenge”

/ K production dominated

by scattering off u-quarks

• & non-trival role of sea quarks

• convolution integral in numerator depends on kT dependence of FF

• differences in dependences on kinematics integrated over

Sivers: Sivers: the “kaon challenge” the “kaon challenge”

/ K production dominated

by scattering off u-quarks

role of sea quarksrole of sea quarks

differences biggest in region where

strange sea is most different from light sea

[PLB666(2008), 446]strange sea pdf

fragmentationfragmentationfunctionfunction

ee++ee--

extracting the extracting the SiversSivers function function

q

qqTpartSIDIS zDxf )()( 11

h

use parametrisations of unpolarised fragmentation functions

see talk by A. Prokudin

transverse nucleon structuretransverse nucleon structure

transversity

via Collins fragmentation fct.

h

h

q q

Collins amplitudesCollins amplitudes

),()(δ 1 Tq pzHxq ),()(δ 1 Tq pzHxq

• positive ≈zero negative

ep X

distinctive pattern:

isospin relation for triplet

fulfilled




ep X


approximation: u-quark dominance

Collins FF has

favoured (u ) and

unfavoured (u -)

transitions of similar size and opposite sign




ep X


approximation: u-quark dominance

Collins FF has

favoured (u ) and

unfavoured (u -)

transitions of similar size and opposite signall asymmetries on deuterium target ≈ zero!

proton data

[note sign change due todifferent angle definition ]



ep hX

K+ amplitudes consistent with amplitudes as expected from u-quark dominance

K of opposite sign from (K is all-sea object)

)()(δA 1)sin(

UTS zHxq q )()(δA 1)sin(

UTS zHxq q

extraction of transversityextraction of transversity

e-

e+

from from Collins Collins asymmetriesasymmetries

Xπe'pe Xhe'de Xee jet21jet

see talk by A. Prokudin

Collins amplitudesCollins amplitudes-- extras: 2D binning ---- extras: 2D binning --

kinematic dependencies often don’t factorise bin in as many independent variables as possible:

z @`fixed’ x Ph @`fixed’ z

z @`fixed’ Phx @`fixed’ z

T

T

Collins amplitudesCollins amplitudes-- extras: 2D binning ---- extras: 2D binning --

kinematic dependencies often don’t factorise bin in as many independent variables as possible:

alternative probe for alternative probe for

transversity: 2-hadronstransversity: 2-hadrons

Xepe

2-hadron production:2-hadron production:

),()(δsin)sin(|S| 21TUT hq

SR MzHxq ),()(δsin)sin(|S| 2

1TUT hq

SR MzHxq

interference fragmentation function between pions in s-wave and p-wave

Xepe 21hh

• only relative momentum of hadron pair relevant

integration over transverse momentum of hadron pair simplifies factorisation (collinear!) and Q2 evolution

• however cross section becomes very complicated (depends on 9! variables)

sensitive to detector acceptance effects

extraction of extraction of amplitudes amplitudes

sin)sin(UT

SRA sin)sin(

UTSRA )sin(

UTSRA )sin(

UTSRA

integration

…facilitate interpretation

projects out sp and pp only for full theta acceptance:


sin)sin(UT

SRA sin)sin(

UTSRA )sin(

UTSRA )sin(

UTSRA

integration

…facilitate interpretation

projects out sp and pp only for full theta acceptance:

acceptance is momentum dependent:

full acceptance


• symmeterization around

fit

bin data in in addition: sin)sin(UT

SRA sin)sin(

UTSRA

&

amplitudesamplitudes

[JHEP 0806.017]

hh++hh-- amplitudes amplitudes

[JHEP 0806.017]

[note sign change due todifferent angle definition]

hh++hh-- amplitudes amplitudes

[JHEP 0806.017]


models for 2-hadron asymmetriesmodels for 2-hadron asymmetries

M (GeV)

[Bacchetta, Radici PRD74(2006)]

models for 2-hadron asymmetriesmodels for 2-hadron asymmetries

M (GeV)

[Bacchetta, Radici PRD74(2006)]


azimuthal dependence of the azimuthal dependence of the

unpolarised cross sectionunpolarised cross section

),(1 Tkxh

spin-orbit effect (Boer-Mulders DF):

correlation between quark transverse motion and transverse spin

unpolarised unpolarised cross sectioncross section

...cos1

2cos UUUUUU dQ

ddd

access to intrinsic quark transverse momentum

analysis challengeanalysis challenge

Monte Carlo:

generated in 4measured insideacceptance

acceptance and radiative effects generate cos(n) moments

analysis challengeanalysis challenge

Monte Carlo:

generated in 4measured insideacceptance

acceptance and radiative effects generate cos(n) moments

5D unfolding of detector andradiative effects:

coscosintrinsic quark transverse intrinsic quark transverse momentummomentum

• very similar result for deuterium

coscosintrinsic quark transverse intrinsic quark transverse momentummomentum


cos2cos2spin-orbit correlationsspin-orbit correlations


models for Boer-Mulders DFmodels for Boer-Mulders DF

• diquark spectator model

• same sign for u & d quark BM-DF


• diquark spectator model

compares well to HERMES data w/o inclusion of tw-4 Cahn effect


• scaled Sivers fct.

• inclusion of tw-4 Cahn effect

[V. Barone, A. Prokudin, Bo-Quiang Ma, PRD78 (2008)]



work in progress for tw-4 Cahn effect[V. Barone, S. Mellis, A. Prokudin]


transversely polarised quarks transversely polarised quarks

in longitudinally polarised in longitudinally polarised

nucleonsnucleons

Kotzinian-Mulders fct.

Kotzinian-Mulders fct.Kotzinian-Mulders fct.

11Lsin2UL HhA

transversely polarised quarks in longitudinal polarised nucleons

next @next @Jlab Jlab

next @HERMESnext @HERMES

pT weighted Sivers & Collins moments

resolve convolution integral !

extraction of all 8 leading tw modulations ++

next @HERMESnext @HERMES

pT weighted Sivers & Collins moments

resolve convolution integral !

extraction of all 8 leading tw modulations ++

next @COMPASSnext @COMPASSrequest to CERN: 2010 full year run (140 days) with

transversely polarised protons

[… investigation of upgrade for higher muon beam intensity

and spectrometer upgrades]

theorytheory

[by Naomi Makins]

looking forward to new projects:Jlab12, EIC, PAX@FAIR

see talks by H. Avakian & R. Ent on friday

BACKUP SLIDESBACKUP SLIDES[courtesy of A. Bacchetta]

Sivers: QSivers: Q22 dependence dependence

factor 2

factor 3

Experimental status: hcos

EMC

E665

ZEUS

c)

Negative results in all the existing measurements

No distinction between hadron type or charge

Experimental status: h2cos

EMC

ZEUS collaborationXhHe

0.12.0 z

222 /7220180 cGeVQ 01.001.0 x 8.02.0 y

ZEUS

Drell-Yan

Positive results in all the existing measurements

No distinction between hadron type or charge (in SIDIS experiments)

Indication of small Boer-Mulders function for the sea quark (from Drell-Yan experiments)

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Delia Hasch