Contalbrigo Marco INFN Ferrara QCD Evolution 13 7 th May 2013, JLab – Newport News

Contalbrigo Marco INFN Ferrara

QCD Evolution 137th May 2013, JLab – Newport News

JLAB12 AND THESTRUCTURE OF HADRONS

Spin degrees of freedom can explain otherwise surprising phenomena and bring new insights into nuclear matter structure

e p → e p

e p → e p

PRC 68, 034325 (2003)

xF

Fundamental: do not neglect it !!

2Contalbrigo M.

The Spin Degree of Freedom

QCD Evolution Workshop, 7th May 2013, JLab

In our exploration of the QCD micro-world

Fundamental: do not neglect spin !!

3Contalbrigo M.

The Spin Degree of Freedom

Two questions in Hadronic Physics await explanation since too long

gqff

f LGLqq )(21

21

pT< 2 GeV/c√s = 20 GeV

xF

AN

Proton Spin Budget Single Spin Asymmetries

? QCD Evolution Workshop, 7th May 2013, JLab

PDFs fpu(x),…

TMD PDFs: fpu(x,kT),…

d 2kT x=

0,t=0

Wpq(x,kT,r) “Mother” Wigner distributions

d3r d 2k

T

Exclusive MeasurementsMomentum transfer to targetDirect info about spatial distribution

Semi-inclusive measurementsMomentum transfer to quarkDirect info about momentum distribution

(FT)

GPDs: Hpu(x,x,t), …

Quantum Phase-space Distributions of Quarks

pT< 2 GeV/c√s = 20 GeV

xF

AN

May solveproton spin puzzle

May explain SSA & Lam-Tung

Probability to find a quark q in a nucleon P with a certain polarization in a position r & momentum k

4Contalbrigo M. QCD Evolution Workshop, 7th May 2013, JLab

A World-wide Challenge


EIC

YOUR TEXT HERE

Limit defined by luminosity

1032

1031

1035

Different Q2 for same x range

EIC

1034

Valence

Complementary experiments

Sea

The SIDIS Landscape


THE JLAB12 FACILITY

6 GeV CEBAF

CHL-2

Upgrade magnets and power supplies

12 GeV CEBAF

Enhance equipment in existing halls

add Hall D (and beam line)

2008-2014: Construction (funded at 99%)

May 20126 GeV Accelerator Shutdown starts

May 2013 Accelerator Commissioning starts

October 2013 Hall Commissioning starts

2013-2015 Pre-Ops (beam commissioning)

Beam current 90 mABeam polarization 85 %


11Contalbrigo M.

Super High Momentum Spectrometer (SHMS)unpolarized SIDIS, hadron ID

Hall-C

Spectrometer Pair, polarized 3He target up to to 1038 cm-2 s-1 hadron ID

Hall-A

Hall-B

CLAS12 H,D polarized targets up to 1035 cm-2 s-1 “complete” acceptance, hadron ID

SOLID 3He, NH3 polarized targets up to 1036 cm-2 s-1 large acceptance, pion ID

Hall-A

JLab12 Experimental Halls


The Hall-C High-momentum Spectrometers

13Contalbrigo M.

Super-HMS11 GeV/c spectrometer

5o-25o angular rangee/h, p/K ID by Cherenkov

HMS7 GeV/c spectrometer10o-90o angular range

e/h, p/K ID by Cherenkov


SIDIS cross-section factorization tests

DC R3R2R1EC

Torus

FTOF

PCAL

HTCC

Solenoid

The CLAS12 Large-Acceptance Spectrometer

14Contalbrigo M.

Luminosity up to 1035 cm-2 s-1

Broad kinematic range coverage (current to target fragmentation)

TOF + RICH for hadron ID

H and D polarized targets

Highly polarized electron beam

RICH


TMDs and GPDs comprehensive study, with special care on applicability

CLAS12 Kinematic Coverage

15Contalbrigo M.

Intermediate anguar range (15-25o) mandatory to reach high PT values

Large electron scattering angles (> 20o) mandatory to reach high Q2 values

Electron

The CLAS12 forward detector is perfectly suitable for high-Q2 and high-pT measurements since designed to cover up to 40 degrees angles

Electron p+acceptance


Advantages: Minimize nuclear background smaller dilution, no attenuation at large pT Weak holding field (BdL ~ 0.1 Tm) wide acceptance, negligible beam deflection

Disadvantages: Very long polarizing times (months) Sensitivity to local heating by charged beams

HD-Ice target vs standard nuclear targets (less luminosity for higher purity)

16Contalbrigo M.

Transversely Polarized HD-Ice Target

HD-ice ran from Nov/11 to May/12 at Jlab R&D work required to run with electron beams

E06-101up to 108 g/sT1 ~ years

Deuterium dilution is under control

Suitable for di-hadron and recoil proton

Ph2 T

R


17Contalbrigo M.

The Hall-A High-Luminosity Spectrometers

Present: spectrometer pair Future: large acceptance detector


High-luminosity3He target

GEM trackersPID challenging

Ultimate statistical precision in the valence region

Polarize 3He Target


PDFS AND TMDS

U L T

U

L

T

Quark polarisation

Nuc

leon

pol

aris

atio

n

T1h

T1fSivers

Pretzelosity

Worm-gear Collinear physicstensor charge

Leading Twist TMDs

20Contalbrigo M.

D-wave componentnot-spherical shape

of the nucleon

Orbital quark motionnon-trivial gauge linkprocess dependence

Proton wave components with

different OAM

L1h

Worm-gear

Proton wave components with

different OAM

Spin effects in unpolarized reactions

1fNumber Density

1gHelicity

1hTransversity

1h

Boer Mulders

pT dependence of quark helicity

pT dependence of number density


N/q U L T

U

L

T

The SIDIS Casequark polarisation

nucl

eon

pola

risat

ion

1fNumber

1gHelicity

T1fSivers

1h

Boer-Mulders

L1h

Density

Worm-gear

Worm-gear

DF

FF

21Contalbrigo M.

T1hTransversity

1h

DF FF

Pretzelosity

SIDIS cross section(transversely pol. target):

Involved phenomenology due to theconvolution over transverse momentum

TMD factorization for PT<<Q


Longitudinal Cross-section

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RDIS0 at Q2∞ due to scattering off spin-½ quarks

RDIS sensitive to gluon and higher-twist effects

RSIDIS(z,pT) = un-integrated RDIS

To be accounted in any TMDasymmetry interpretation


Cornell data of 70’s

E12-06-104 Hall-C

At pT > 0.2 GeV/c use dependencies measured in CLAS12 experiment

Small-Ph Dependence

23Contalbrigo M.

Map pf pT dependence for pion off proton and deuteron targets

T QCD Evolution Workshop, 7th May 2013, JLab

E12-09-017 Hall-C

Hall C - JLab

Perturbative regionCollinear factorization

Non-perturbative TMD factorization

Unpolarized Target


Boer-Mulders spin-orbit effect

E12-06-112 Hall-B

Band: Phys Rev D78 034035Boer-Mulders from DY data

Collins from chiral limit

Line: Phys Rev D78 045022Boer-Mulders from Sivers

Collins from e+e- data

kaon

Unpolarized Target


E12-09-008 Hall-B

In the perturbative limit 1/PT behavior expected ALU~ 1/Q (Twist-3)

Measurements of kinematic (x,Q2,z,PT) will probe HT distribution functions

E12-06-112 Hall-B

ep e’ KX

kaon

Unpolarized Target


E12-09-008 Hall-B

In the perturbative limit 1/PT behavior expected ALU~ 1/Q (Twist-3)

Measurements of kinematic (x,Q2,z,PT) will probe HT distribution functions

E12-06-112 Hall-B

ep e’ KX

Quark Helicity


E12-07-104 Hall-B

E12-06-109 Hall-B

E12-06-122 Hall-A

E12-06-110 Hall-C

Transverse momentum dependenceof quark helicity vs number densityQuark helicity at high-x is sensitive

to orbital angular momentum.

Quark Helicity at High-x


E12-07-104 Hall-B

Transversity Signals

29Contalbrigo M.

1st collinear extraction !

hXlld '

hXllp '

1st extraction of Transversity!

Anselmino et al. Phys. Rev. D 75 (2007)

Soffer bound

xh1(

x)d

xh1(

x)u

xh1(

x, k

)T

uxh

1(x,

k )T

d

Bacchetta et al., PRL 107 (2011)

NO DATA

Gauss Ansatz

High-x and tensor charge

Gaussian ansatz & role of Q2 evolution ?


The Sivers effect

30Contalbrigo M.

Non zero signals for p+ and K+

Significant Q2 evolution ?

K+ signals larger than p+?

K+-p

T3 correlator from pp Sivers moment from SIDIS

Sign change is a crucial test of TMDs factorization

Coverage at large x and relation with Drell-Yan

Sign mismatch between SIDIS and pp SSA ?

Coverage at large pT and x and relation with twist-3 collinear approach

HERMES p

?

?

x

arXiv:1112.4423

arXiv:1107.4446

Related to quark orbital angular

momentum


CLAS12 Projections

31Contalbrigo M.

Collins asymmetry

Large x important to constrain the tensor charge

Sivers asymmetry

High resolution and broad range in pT to test perturb. non-perturb. transient and for Bessel function analysis


C12-11-111 Hall-B

Statistical Precision @ CLAS12

32Contalbrigo M.

Statistical errors 4D analysis on p+


Statistical Precision @ CLAS12


Q2 dependence of Sivers asymmetry Test of TMDs evolution

Di-hadron channel for h1

Test of TMDs extraction

E12-12-109 Hall-B

Sensitivity to so-far not-observed distributions

C12-11-111 Hall-B

34Contalbrigo M.

Precise 3D measurementon 3He with hadron ID ✓ neutron TMD ✓ flavor separation

)X 40 days

3He AUT with Super-BigBite


E12-11-007 Hall-A

35Contalbrigo M.

3He Target with SOLID

AUT

AUL


Luminosity: up to 1036 cm-2 s-1

Acceptance:

Electron 8-26 degreesPion 8-16 degrees

Forward detector

Large angle detector

E12-10-006 Hall-A

E12-11-007 Hall-A

AUT

AUL

36Contalbrigo M.

NH3 Target with SOLID

C12-11-108 Hall-A

J.-P. Chen


FFS AND GPDS

Generalized parton distributionsEncompass parton distributions and form factors

Longitudinal momentum and transverse spatial positioncorrelated information

Access OAM Lq= Jq-½S via Ji sum rule


GPDs from FFs


Inconsistency in DATA ?

Diehl et al. arXiv: 1302.4604

Bacchetta et al. arXiv: 1107.5755

40Contalbrigo M.

Nucleon Form Factors at High Q2


Ratio of quasi-elastice-p to e-n scatterings off a deuteron target

Related to GPDs at high |t| structure of the nucleon at small transverse distances

E12-09-019 Hall-A

E12-07-104 Hall-B

Nucleon Form Factors at High Q2


Ratio of recoil polarizations

E12-11-009 Hall-C

Asymmetry in quasi-elastic scattering

E12-09-016 Hall-AE12-07-109 Hall-A

42Contalbrigo M.

DVCS


E12-06-114 Hall-A

p-DVCS AUL and ALU @ CLAS12

43Contalbrigo M.

120 daysbeam time

AUL

Q2

Q2

x

x

ALU

-t

85 daysbeam time


C12-06-119 Hall-B

p-DVCS AUT @ CLAS12


C12-12-010 Hall-B

ALTAUTALTAUT

d-DVCS ALU @ CLAS12


E12-11-003 Hall-B

DVMP


Exclusive p and k Electro-production


E12-07-105 Hall-C

E12-09-011 Hall-C

Exclusive f and the Gluonic Radius


From t slope average impact parameter

E12-12-107 Hall-B

The JLab12 Charge

49Contalbrigo M.

Complete mapping (3D) of the nucleon in the valence regionHigh potential of the complementary programs of 3 experimental halls


Start of Accelerator commissioning expected in Novemberand running beam to Hall-A in February 2014

Documents

Contalbrigo Marco INFN Ferrara QCD Evolution 13 7 th May 2013, JLab – Newport News