delia hasch
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Delia Hasch. TMDs & friends from lepton scattering -experimental overview-. outline:. introduction: some reminders… status Sivers DF Collins DF azimuthal dependence of unpolarised xsection the ‘soon to come’ menu. - PowerPoint PPT PresentationTRANSCRIPT
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
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
T
plateau at high Ph
T dominated by u-quarks
u-quark Sivers DF < 0
cancellation for :
u and d quark Sivers DF
of opposite sign
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
cancellation for :
u and d quark Sivers DF
of opposite sign all asymmetries on deuterium target ≈ zero!
[PLB673(2009)]
Sivers Sivers amplitudesamplitudes forfor
[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
Collins amplitudesCollins amplitudes
),()(δ 1 Tq pzHxq ),()(δ 1 Tq pzHxq
• positive ≈zero negative
ep X
distinctive pattern:
approximation: u-quark dominance
Collins FF has
favoured (u ) and
unfavoured (u -)
transitions of similar size and opposite sign
Collins amplitudesCollins amplitudes
),()(δ 1 Tq pzHxq ),()(δ 1 Tq pzHxq
• positive ≈zero negative
ep X
distinctive pattern:
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 ]
Collins amplitudesCollins amplitudes
),()(δ 1 Tq pzHxq ),()(δ 1 Tq pzHxq
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:
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:
acceptance is momentum dependent:
full acceptance
extraction of extraction of amplitudes amplitudes
• 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]
[note sign change due todifferent angle definition]
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)]
[note sign change due todifferent angle definition]
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
• very similar result for deuterium
cos2cos2spin-orbit correlationsspin-orbit correlations
• very similar result for deuterium
models for Boer-Mulders DFmodels for Boer-Mulders DF
• diquark spectator model
• same sign for u & d quark BM-DF
models for Boer-Mulders DFmodels for Boer-Mulders DF
• diquark spectator model
compares well to HERMES data w/o inclusion of tw-4 Cahn effect
models for Boer-Mulders DFmodels for Boer-Mulders DF
• scaled Sivers fct.
• inclusion of tw-4 Cahn effect
[V. Barone, A. Prokudin, Bo-Quiang Ma, PRD78 (2008)]
models for Boer-Mulders DFmodels for Boer-Mulders DF
models for Boer-Mulders DFmodels for Boer-Mulders DF
work in progress for tw-4 Cahn effect[V. Barone, S. Mellis, A. Prokudin]
models for Boer-Mulders DFmodels for Boer-Mulders DF
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)