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3.5 exhausting days
Decaliters of coffee
Hectoliters of wine
Trucks of delicious food
Great conference dinner
45 talks
Tons of NEW experimental data do digest
> 1000 pages of theoretical contributions
--- not neccessarily edible without further
cooking
No One Can Encompass
Unencompassable *
(Transversity-2008 Summary)
Kolya Nikolaev
Institut f. Kernphysik, FZJ, Juelich, Germany
and
L.D.Landau Institute, Chernogolovka, Russia
*) Kozma Prutkov, Russian poet & philopsopher
Milestones:
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Quark helicity conservation: death to high energy transverse
spin physics (1978; personal recollection of 80´s with Tolya Efremov
asking at each and every meeting how to circumvent that no-go theorem)
30 years ago: Ralston-Soper, groundbreaking transvsersiity signal in DY
A decade of an (agressively) dormant community ... till circa 90..
E704 + early data
Sivers function (1990) .... Quite an ordeal for Dennis
Collins function (1993)
A to Z TMD functions ... Giant catalogues of observables, leading and
higher twist...
1995: first ideas on CF in e+e- (Kotzinian)
HERMES, COMPASS, RHIC: quantifying the effects
BELLE and Cagliari-Torino: birth of a sound quantitative phenomenology
2002: transversity Bible (BDR, Phys.Rept.), Como & Ferrara....
2004: an idea of PAX at FAIR (golden plated DY). J-PARC, UNK in
Protvino (?)... RHIC (?), COMPASS (?)
Today: Mature subject ripe for offspings!
The PRIN Transversity Project
PRIN2003: Measurement of the Nucleon Transversity (approved)
 Transversity 2005 in Como
PRIN2006:
Study of transverse spin effects in the nucleon (approved)
 Transversity 2008
35 participants
•
•
theoretical physicists
experimental
physicists
COMPASS
HERMES
future projects
F.B., Transversity 2008, May 28, 2008
Quark structure of the nucleon
q
f 1=
unpolarised quarks
and nucleons
q
g 1=
−
longitudinally
polarised quarks and
nucleons
hq1 =
−
transversely polarised
quarks and nucleons
Only a
glimpse !
D.Boer
Elliot Leader: vindication of a transverse spin SR
Nice lecture in angular momentum and Lorentz group
Technical Realization of FAIR
SIS 100/300
SIS 18
UNILAC
Radioactive Ion
Production Target
Existing facility: provides
ion-beam source and injector for FAIR
HESR
Super
FRS
Accelerator Components & Key Characteristics
Ring/Device
Beam
SIS100 (100Tm)
SIS300 (300Tm)
Energy
protons
30 GeV
4x1013
238
U
1 GeV/u
5x1011
(intensity factor 100 over present)
Ar
45 GeV/u
2x109
U
34 GeV/u
2x1010
ion and antiproton storage and
experiment rings
antiprotons
14 GeV
~1011
HESR
Super-FRS
CR
FLAIR
100 m
40
238
CR/RESR/NESR
Anti-Proton
Production Target
Intensity
rare-isotope beams 1 GeV/u
<109
RESR
NESR
New future facility: provides ion and anti-matter
beams of highest-intensity and up to high energies
Polarized proton acceleration at J-PARC
pC CNI Polarimeter
PHOBOS
Pol. H Source
Absolute Polarimeter RHIC pC
(H↑ jet)
Polarimeters
rf Dipole
PHENIX
STAR
180/400 MeV Polarimeter
30% Partial
Helical Siberian Snakes
Collaboration with BNL
Pol. H- Source
LINAC
BRAHMS
Extracted
& PP2PPBeam
Polarimeter
BOOSTER
rf Dipole
AGS
200 MeV
Polarimeter
Warm Partial
Helical Siberian Snake
AGS Internal
Polarimeter
Cold Partial
Helical Siberian Snake
AGS pC Polarimeters
11
ATT for PAX Kinematic Conditions
s~200 GeV2, τ=x1x2=M2/s~0.05
→ Exploration of valence quarks
h1q(x,Q2) large
ATT/aTT > 0.2
Models predict |h1u|>>|h1d|
At x1=x2 ATT~h1u2
xF=x1-x2
Anselmino et al., PLB 594,97
(2004)
Efremov et al., EPJ C35,
207 (2004)
Mikhail Nekipelov
s~200 GeV2 ideal:
• Large range in xF
• Large asymmetry, (h1u/u)2 ~ ATT
PAX
12
NLO:ransversity ssignal is robust, don‘t be affraid of
subasymptotic energy.
Jiang: SIDIS at JLAB at 6 GeV (also H.Avakian for pi-zero)
Georg Christoph Lichtenberg (1742-1799)
“Man muß etwas Neues machen, um etwas Neues zu sehen.”
“You have to make something new,
if you want to see something new”
H.Stroeher
~ 3 years ago, we proposed a
method to polarize antiprotons
by „spin-filtering“
H.Stroeher
Spin-filtering at TSR: „FILTEX“ – proof-of-principle
PhD of F. Rathmann
 Spin filtering works for protons
Also spin filtering of neutrons in polarized He-3 target
H.Stroeher
Proposed methods (2): Recent paper
 Need for an experimental test of this idea !
H.Stroeher
Depolarization Studies at COSY: Results
−ln
σ depol =

Pdet uned
P nominal

Δt⋅d t⋅f rev
!! Preliminary !!
 No effect observed, i.e. cross section must be
many orders-of-magnitude smaller than 1013b !
v/c ~
0.002
O.Teryaev & A.Bacchetta & L.Gamberg & A.Mukherjee:
(non)factorization and mismatches
•
•
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•
Known knowns
Known unknowns
Unknown knowns
Unknown unknowns
•
Matching & mismatching different --- perturbative vs.
nonperturbative --- mechanims & different formalisms --GPM (Torino style) vs. Twist-3 (Qiu-Sterman,...), gluon pole
contributions....
•
Color factors upset universality of the Sivers funstion?
Non-factorization ???
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What about -1 from SIDIS to DY? Looks safe?
Collins function is a problem free one?
Perdekamp: Collins Effect in di-Hadron
Correlations
In e+e- Annihilation into Quarks!
Collins effect in e+equark fragmentation
will lead to azimuthal
asymmetries in di-hadron
correlation measurements!
electron
π
z2
−
q1
q2
quark-2
spin
z1,2 relative pion
momenta
π
quark-1
spin
positron

z1
Experimental requirements:
 Small asymmetries 
very large data sample!
 Good particle ID to high
momenta.
 Hermetic detector
DELPHI:
Kotzinan (1995)
Efremov, Smirnova, Tkachev (Nucl. Phys. Proc. Suppl. 74, 1
P2 in ppm
mple: 3.5 x 106 events at √s=MZ0
∣ ∣=6.2±1.7 stat . error 
D1
H1
∣ ∣=12.9±1.4 stat . error 
D1
irst result on Collins Asymmetries in e+eonte Carlo for acceptance corrections
n-estimated systematic errors
DELPHI result e+e- compatible with
HERMES+ BELLE (Efremov, Goeke, Schweitzer)
35<θ2<135
15< θ2 <175
endcaps
H1
endcaps
alysis: di-hadron correlation for
leading hadrons
Perdekamp: Collins Asymmetries:
sin2 θ/(1+cos2 θ) Binning (UL)
PRELIMINARY
thrustz
θ2
Nonzero quark
polarization ~ sin2 θ
Unpolarized de-nominator
~ 1+cos2 θ
Clear linear behavior seen
when using either
thrustz or 2nd hadron
as polar angle
Better agreement for
thrust axis
(~approximate quark
axis)
UC plots similar
Wolfgang Shafer‘s question
e+e C-Cbar  beta decays
C = muon
Spin of the muon from P-odd electron angular distribution
(mSR studies of condensed matter, (g-2) etc.)
Dilepton spectrum at a parton level: a component from the
spin-spin correlation – a counterpart of the Collins X Collins
Is the signal robust against hadronization of a polarized
charmed quark?
Not at all: hadronization ends up in strong decays of all the
spinning charmed hadrons into spinless D‘s
Parity violating asymmetry is entirely wiped out (by
hadronization)
The point is almost found in Dalitz, Goldstein, Marshall
(1988,1989)
Can hadronization affect our factorzation prejudice ??????
HERMES: Collins moments for pions (2002-2005)
• positive amplitude for π+
• ∼ 0 amplitude for π0
• negative amplitude for π-

−
u⇒ π ;d ⇒ π  fav 
u⇒ π − ;d ⇒ π unfav 
−
the large negative π amplitude
suggests disfavored Collins function
with opposite sign:
I [ q ( x) H1 q ( z )] ¿ 0
Transversity & Collins FF ≠ 0
We are in a good shape:
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Collins = +++
Sivers = ++
Transversity = +
Boer-Mulders for pions = +
Iinterference FF = +
Relating SIDIS, e+e- and pp = + (more
theoretical work on non-factorization is
called upon)
• Future: RHIC, COMPASS, PAX @FIAR,
JPARC, TMDs at JLAB
• Why do we waste asntiprotons at
Fermilab?
HERMES: Sivers moments for pions (2002-2005)
• positive amplitude for π+
• positive amplitude for π0
• amplitude ∼ 0 for π-
I [ f1T q ( x) D1q ( z )] ¿ 0
Sivers function ≠ 0
Lq ≠0
HERMES: Pions vs. Kaons : Sivers moments
• K+ amplitude is ∼2 times
larger than for π+:
conflicts with usual expectations
based on u-quark dominance
π ≡u , d 
K  ≡u, s 
suggests substantial magnitudes
of the Sivers function for the sea
quarks
−
• Both K and
π − amplitudes
are consistent with zero
Predictions from the global analysis, Collins
Update of the analysis with the most recent
COMPASS Deuteron, HERMES Proton, BELLE e+ e- data
COMPASS proton data for h+ and h-, with the very last predictions of
Anselmino et al. ( DIS08 by A.Prokudin. )
S. Levorato, Transversity 2008 May 28-31 - Ferrara, Italy
29
D.Boer
Sivers function (hep-ph 0805.2677)
vs COMPASS acceptance.
Sivers distribution
function for u, d flavor
for SIDIS
sign to be reversed for DY
Marialaura Colantoni - Transversity 2008
31
M.Maggiora for Panda: Conclusions on DY
MORE EXTENDED SIMULATIONS ARE NEEDED
• B40cm Fe x E64cm FE rejection factor considering μ couples: 6 105
• E64cm Fe x E64cm FE rejection factor considering μ couples: 106
(30cm more Fe: not enought statistics, > 5 106)
These rejection factor includes primary pions and secondary muons
from primary pions; rejection factor for secondary particles: 5 104 , 105
At least two order of magnitude are missing; extrensive simulations
undergoing on the GRID (64Mev) to design topological and kinematic
cuts:
• pT seletion not yet applied
• E64cm Fe x E64cm FE and B40cm Fe x E64cm FE : increase S/B
Investigated τ region → τ ~ 4 10-2
May 29, 2008
Background studies for DY @ PANDA
32
C.Aidala for BRAMS & PHENIX
AN(π) at √s = 62.4 GeV
Submitted to PRL
arXiv:0801.1078
Twist 3
Sivers
Large AN(π): 0.3-0.4 at xF~0.6, pT~1.3 GeV
Strong xF-pT dependence. Though |AN(π+)| ~ |AN(π−)|, |AN(π+)/AN(π−)| decreases with xF-pT
Les Bland for STAR
Summary
• Firmly established that large transverse single spin asymmetries are observed at
√s = 200 GeV, where generally cross sections agree with pQCD calculations.
• Large transverse single spin asymmetries are observed only at large xF;
midrapidity asymmetries are small.
• Large xF spin asymmetries show the same pattern for 20 ≤ √s ≤ 200 GeV
• First observation of pT dependence at fixed-xF, enabled by the run-6
luminosity/performance
⇒ Some aspects of the theory are still not understood
• Forward calorimeter with 20x larger acceptance now in place and operational at
STAR. Near-term future includes prospects for direct photon transverse spin
physics. Longer-term future heading towards transverse spin Drell-Yan.
A.Bianconi
 Non-vanishing analyzing power for forward
neutrons
 Expect similar anlyzing power for protons
 Invoke the inclusive-exclusive duality: pppX
vs. pp pp
 Sivers in inclusive  relate SSA in elastic to
Sivers
 Complications with multiple scattering in elastic
scattering (counterpart of FSI in SIDIS... ) --- that
was Andrea‘s main concern
 To be studied further: no real discussions of soft
multiple sacttering of secondary hadrons so far
Gary Goldstein: Important ingredients for relating transversity
to exclusive π0 electroproduction
Tensor charge couples via σµνγ5 to nucleons (Gamow-Teller)
Coupled quantum numbers 1+- correspond to b1 & h1 couplings
(γµ γ5 is opposite C-parity & does not contribute)
γ* + π0 is C-parity eigenstate coupling to
 1+- q+anti-q states (S=0, L=1…) ⇒ b 0 & h
1
1
 1- - q+anti-q states (S=1, L=1…) ⇒ ρ0 & ω
γ*L + π0 does not couple to ρ0 & ω at small angles, but b10 & h1 do
couple
γ*T + π0 couples to both sets
Factorization proofs: QCD →γL . Applicable to γT & GPDs?
Different transition form factors ρ0 → π0 & b10 → π0
Which picture - Regge or partons? Both connected…
Absorption (multiple scattering) corrections are important
S.Scopetta (also L.Gamberg, A.Kotzinian, M.Radici, P.Schweitzer...)
(severe model dependence of BHS evlauation)
M.Burkart: almost a quantum mechanical model for
Sivers function
GPDs: distribution of partons in impact parameter space
transverse polarization (of nucleon or quark)
--> significant deformation of impact parameter distributions
+ FSI by chromodynamic lensing --> transverse SSA
Sivers: sign from anomalous magnetic moment (u<0; d>0)
Boer Mulders: ``universal sign'' (negative)
J.C.Peng: Azimuthal cos2Φ Distribution in p+d Drell-Yan
Lingyan Zhu et al., PRL 99 (2007) 082301
With Boer-Mulders function h1┴:
ν(π-Wµ+µ-X)~ [valence h1┴(π)] * [valence h1┴(p)]
ν(pdµ+µ-X)~ [valence h1┴(p)] * [sea h1┴(p)]
ν>0 suggests same sign for the valence and sea BM functions
J.C.Peng: Pion Boer-Mulders Function
Final-state interaction with one gluon exchange can produce nonzero h1┴
for the pion in the quark-spectator-antiquark model with constant coupling
gπ.
Lu&Ma, PRD70,094044(2004).
The quark-spectator-antiquark model with effective pion-quarkantiquark coupling as a dipole form factor Lu & Ma, hep-ph/0504184
Pion-cloud model gives proton sea-quark BM
John Ralston
John Ralston
Conclusions
:
We are in a good shape: tremendous
progress since Transversity-2005 in Como
•
•
•
•
•
•
•
Collins = +++
Sivers = ++
Transversity = +
Boer-Mulders for pions = +
Iinterference FF = +
Relating SIDIS, e+e- and pp = + (more theoretical
work on non-factorization is called upon)
Future: RHIC, COMPASS, PAX @FIAR, JPARC
Thanks to everybody for a success of this meeting!
Oleg Teryaev: Outline
Leading and higher twists
Single Spin Asymmetries in QCD - Sources of (I)FSI
5 ways from Sivers to Twist 3
5th way – justifying “old Torino recipe”
Non-universality of Sivers function: Colour
correlations
Sum rules and global fits for effective Sivers function
Conclusions
Oleg Teryaev: Compatibility of SSA and DIS
Extractions of and modeling of Sivers function: – “mirror”
u and d(talks of E.Boglione, S.Scopetta )
FSecond moment at % level
Twist -3 - similar for neutron and proton and of the
same sign –g2no mirror picture seen –but supported by
colour ordering!
Scale of Sivers function reasonable, but flavor
dependence differs qualitatively.
Inclusion of pp data, global analysis including gluonic
(=Sivers) and fermionic poles
HERMES, RHIC, E704 –like phonons and rotons in liquid
helium; small moment and large E704 SSA imply
oscillations
JLAB –measure SF(talk of X. Jiang) and g2 in the same
run
Results: Collins asymmetry
Clear effect, asymmetry different from zero,
First time asymmetry results different from zero at COMPASS (proton target)
 Small asymmetry at small x, compatible with zero
 Asymmetry of opposite sign for positive and negative hadrons, same strength and
sign of HERMES, result which is not obvious due the different kinematic range of the
two experiments.

Overall systematic error has been evaluated to be 0.3 σstat for Collins asymmetry for this
analysis.
S. Levorato, Transversity 2008 May 28-31 - Ferrara, Italy
49
IFF