H.Avakian, JLab, Oct 29 1 Studies of spin-orbit correlations H.Avakian (JLab) H.Avakian (JLab) Transverse Spin Phenomena and Their Impact on QCD a Workshop in Honor of Gary Goldstein's 70th Birthday October 28-29, 2010 Thomas Jefferson National Accelerator Facility
Studies of spin-orbit correlations. H.Avakian (JLab). Transverse Spin Phenomena and Their Impact on QCD a Workshop in Honor of Gary Goldstein's 70th Birthday October 28-29, 2010 Thomas Jefferson National Accelerator Facility. Outline. - PowerPoint PPT Presentation
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H.Avakian, JLab, Oct 29 1
Studies of spin-orbit correlations
H.Avakian (JLab)H.Avakian (JLab)
Transverse Spin Phenomena and Their Impact on QCD a Workshop in Honor of Gary Goldstein's 70th
BirthdayOctober 28-29, 2010
Thomas Jefferson National Accelerator Facility
H.Avakian, JLab, Oct 29 2
Outline
Transverse structure of the nucleon and partonic correlations
•Physics motivation•kT-effects in double spin asymmetries•Physics with transversely polarized hadrons and quarks
–kT-effects and SSA in pion production –Higher twist effects–Kaon puzzle
•Future studies of 3D PDFs at CLAS at 6 GeV •Transverse structure & CLAS12•Summary
H.Avakian, JLab, Oct 29 33
Cross section is a function of scale variables x,y,z
z
SIDIS kinematical plane and observablesSIDIS kinematical plane and observables
U unpolarized
L long.polarized
T trans.polarizedBeam polarizationTarget polarization
sin2moment of the cross section for unpolarized beam and long. polarized target
Large PT range and full coverage in azimuthal angle crucial for studies
H.Avakian, JLab, Oct 29 1010
coscos moment in A moment in ALLLL-P-PTT-dependence-dependence
PT-dependence of cos moment of double spin asymmetry is most sensitive to kT-distributions of quarks with spin orientations along and opposite to the proton spin.
hep-ph/0608048
02=0.25GeV2
D2=0.2GeV2
CLAS PRELIMINARY
H.Avakian, JLab, Oct 29 11
A1 PT-dependence in SIDIS
M.Anselmino et al hep-ph/0608048
+ A1 suggests broader kT distributions for f1 than for g1
- A1 may require non-Gaussian kT-dependence for different helicities and/or flavors
02=0.25GeV2
D2=0.2GeV2
0.4<z<0.7
arXiv:1003.4549
H.Avakian, JLab, Oct 29 12
A1
A1 PT-dependence
CLAS data suggests that width of g1 is less than the width of f1
AnselminoCollins
Lattice
New CLAS data would allow multidimensional binning to study kT-dependence for fixed x
PT
PT
arXiv:1003.4549
H.Avakian, JLab, Oct 29 13
Beam SSA: ALU from CLAS @ JLab
0.5<z<0.8
Beam SSA from hadronization (Collins effect) by Schweitzer et al.
•Study the Collins function of kaons•Provides independent information on the RSMT TMD
Kotzinian-Mulders Asymmetry
proton deuteron
Pasquini et al.
H.Avakian, JLab, Oct 29 25
Some questions to address in future
• What is the shape of kT-distributions?• Can kT-distributions be flavor dependent?• Are kT-distributions the same for different spin orientations?• How spin-orbit correlations change the momentum
distributions?• How big are quark-gluon correlations?• How nuclear medium changes kT-distributions?• What is the fraction of kT-generated in FSI?• How gluons and sea are distributed in kT
How spin-orbit correlations are related to the longitudinal structure and nuclear effects?
H.Avakian, JLab, Oct 29 26
Summary
•CLAS longitudinally polarized NH3 and ND3 target data provides superior sample of events allowing detailed studies of single and double spin asymmetries using multidimensional bins
Measurements of spin and azimuthal asymmetries with unpolarized, longitudinally polarized and transversely polarized targets in semi-inclusive processes at CLAS/CLAS12 will :
•Measure TMDs of partons in the valence region•Provide detailed info on partonic spin-orbit correlations •Study quark-gluon correlations (HT)•Study nuclear modification of 3D PDFsWe’ll try hard to keep you busy next 10-15 years!
H.Avakian, JLab, Oct 29 27
Support slides….
M.Osipenko
H.Avakian, JLab, Oct 29 29
HERMES/COMPASS
Berger
H.Avakian, JLab, Oct 29 3030
~10% of E05-113 data
30
Longitudinal Target SSA measurements at CLAS Longitudinal Target SSA measurements at CLAS
p1sin+p2sin2
0.12<x<0.48
Q2>1.1 GeV2
PT<1 GeV
ep→e’X
W2>4 GeV2
0.4<z<0.7
MX>1.4 GeV
y<0.85 p1= 0.059±0.010p2=-0.041±0.010
p1=-0.042±0.015p2=-0.052±0.016
p1=0.082±0.018p2=0.012±0.019
CLAS-2009 (E05-113)CLAS PRELIMINARY
CLAS-2000
Data consistent with negative sin2 for +
H.Avakian, JLab, Oct 29 31
Kotzinian-Mulders Asymmetries
B.Musch arXiv:0907.2381B.Pasquini et al, arXiv:0910.1677
HERMES
CLAS (5 days)
Worm gear TMDs are unique (no analog in GPDs)
H.Avakian, JLab, Oct 29 323232
Single hadron production in hard scattering
xF - momentum
in the CM frame
xF>0 (current fragmentation)
xF<0 (target fragmentation)
h
h
Target fragmentation
Current fragmentation
Fracture Functions
xF
M
0-1 1
h
h
TMD GPD
kT-dependent PDFs Generalized PDFs
PDF
hFF
DA DA
exclusivesemi-inclusive semi-exclusive
You think you understand something? Now check your target fragments!
H.Avakian, JLab, Oct 29 333333
Quark distributions at large kQuark distributions at large kTT
Higher probability to find a hadron at large PT in nuclei
kT-distributions may be wider in nuclei?
PT = p┴ +z kT
bigger effect at large z
Understanding of modification of kT widths in nuclei is important also for nucleon TMDs
H.Avakian, JLab, Oct 29 3434
kT and FSI
l l’
x,kT
proton
spectator system
•The difference is coming from final state interactions (different remnant)•Studies of DIS and SIDIS with nuclear targets provide info on kT
Tang,Wang & Zhou
Phys.Rev.D77:125010,2008
BHS 2002Collins 2002Ji,Yuan 2002
lT
l l’
x,k’T l’T
spectator systemnucleus
total transverse momentum broadening squared
~4 n, with ~4-6 MeV
soft gluon exchanges included in the distribution function (gauge link)
AALLLL P PTT-dependence in SIDIS-dependence in SIDIS
M.Anselmino et al hep-ph/0608048
•New experiment with 10 times more data will study the PT-dependence for different quark helicities and flavors for bins in x to check if 0< 2
02=0.25GeV2
D2=0.2GeV2
0.4<z<0.7
E05-113
H.Avakian, JLab, Oct 29 41
H. Avakian, JLab, May 34141
SIDIS: partonic cross sections
kT
PT = p┴ +z kT
p┴
Ji,Ma,Yuan Phys.Rev.D71:034005,2005
Is the info on x-kT correlations accessible in kT integrated observables?
H.Avakian, JLab, Oct 29 42
Extracting widths from A1
Assuming the widths of f1/g1 x,z and flavor independent
Anselmino et al
Collins et al
Fits to unpolarized data
EMC
H.Avakian, JLab, Oct 29 43
Dilution factor in SIDIS
Multiple scattering and attenuation in nuclear environment introduces
additional PT-dependence for hadrons
Fraction of events from polarized hydrogen in NH3
Nu,Np -total counts from NH3 and carbon normalized by lumi
u, p -total areal thickness of hydrogen (in NH3), and carbon target
Cn=Nitr/Carbon ratio (~0.98)Diff. symbols for diff x-bins
-
H.Avakian, JLab, Oct 29 44
EMC Effect
I. Cloet (Argonne-2010)
NJL-model In medium quarks are more relativisticq more sensitive to angular momentumLower components of wavefunctions more enhancedLower components carry more angular mom.
44H. Avakian, JLab, May 3
In medium modificationMass, magnetic moment, sizeForm factors, PDFs, GPDs, TMDs, etc
How sensitive are inclusive measurements to the transverse structure of nucleon and nucleus ?