Top Banner
Hadronization and Quark Propagation in Nuclear Medium Jian-ping Chen, Jefferson Lab INT09 on JLab 12 GeV, Oct.26-30, 2009 Introduction Hadronization and Nuclear medium effects Current status of nuclear SIDIS to study hadronization JLab 12 GeV program on hadronization CLAS12 (large acceptance) (Will Brook’s talk) SHMS+HMS (high luminosity/small acceptance) What can high luminosity/small acceptance measurements contribute? Opportunity with SoLID (high luminosity/large acceptance) Summary Acknowledgement: Thanks to A. Accardi, K. Wang and B. Norum for
40

Hadronization and Quark Propagation in Nuclear Medium

Jan 07, 2016

Download

Documents

lave

Hadronization and Quark Propagation in Nuclear Medium. Jian-ping Chen, Jefferson Lab INT09 on JLab 12 GeV, Oct.26-30, 2009. Introduction Hadronization and Nuclear medium effects Current status of nuclear SIDIS to study hadronization JLab 12 GeV program on hadronization - PowerPoint PPT Presentation
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: Hadronization and Quark Propagation in Nuclear Medium

Hadronization and Quark Propagation in Nuclear Medium

Jian-ping Chen, Jefferson LabINT09 on JLab 12 GeV, Oct.26-30, 2009

Introduction

Hadronization and Nuclear medium effects

Current status of nuclear SIDIS to study hadronization

JLab 12 GeV program on hadronization

CLAS12 (large acceptance) (Will Brook’s talk)

SHMS+HMS (high luminosity/small acceptance)

What can high luminosity/small acceptance measurements contribute?

Opportunity with SoLID (high luminosity/large acceptance)

Summary

Acknowledgement: Thanks to A. Accardi, K. Wang and B. Norum for providing plots

and nice pictures. Also “borrowed” from colleague’s talks.

Page 2: Hadronization and Quark Propagation in Nuclear Medium

Introduction

Nuclear Medium as a Laboratory to Study QCD

Page 3: Hadronization and Quark Propagation in Nuclear Medium

Strong Interaction and QCD• Strong interaction, running coupling ~1 -- QCD: accepted theory for strong interaction -- asymptotic freedom (2004 Nobel) perturbation calculation works at high energy -- interaction significant at intermediate energy quark-gluon correlations -- interaction strong at low energy confinement -- gluons self interacting

• A major challenge in fundamental physics: -- Understand QCD in all regions, including strong

(confinement) region

• Fundamental degrees of freedom: quarks, gluons Natural effective degrees of freedom: hadrons -- transition and relation between two pictures E

s

Page 4: Hadronization and Quark Propagation in Nuclear Medium

Confinement and Nucleon

• Colors are confined in hadronic system• Can not directly detect quarks/gluons (colored objects)• Only hadron (color singlet) properties are observables • Observables are gauge invariant

• Both nucleon and nucleus are good laboratories to study QCD• Nucleon: simpler, often can use fundamental DOF to describe processes

• pQCD, description of hadronic properties in terms of quarks/gluons• It is only an approximation at any finite Q2

• power (twist) corrections and order (as) corrections• Multi-parton correlations• Partons in-separable from gluon field due to gauge invariance • Beyond co-linear factorization • Multi-dimensional structure and distributionsTransverse dimension is crucial for complete understanding QCD

Page 5: Hadronization and Quark Propagation in Nuclear Medium

Confinement and Hadronization

• Confinement from a simple experimentalist point of view:• DIS directly probe partons, which always hadronize on the

way out can not directly detect partons

• Hadronization is one of the fundamental processes in QCD• Colored objects always interact with gluon field/sea to

become color neutral before being detected• Nuclear medium provides a natural laboratory to study

hadronization• Understanding cold matter quark propagation important for

hot matter study

Page 6: Hadronization and Quark Propagation in Nuclear Medium

QCD and Nuclei

• Most of the strong interaction confined in nucleon, only residual strong interaction remains among nucleons in a nucleus (exponential tail?)• Effective N-N interaction with meson exchange

• Study QCD with nuclei• Short range not well understood: Short range correlations• Nuclei at extreme conditions: QGP, CGC (gluon saturation)• Nuclear medium effects

• EMC effect• Coulomb Sum Rule quenching(?)• Form Factor Modification(?) in 4He• Color Transparency • Quark propagation in cold and hot nuclear matter

Page 7: Hadronization and Quark Propagation in Nuclear Medium

Short-Range Correlation Pair Factions

R. Subedi et al., Science 320 (2008) 1476).

7

Page 8: Hadronization and Quark Propagation in Nuclear Medium

Short Range Correlations and Cold Dense Matter

Mean field

MF+2-N SRC

MF+multinucleon SRC

• SRC accessible at 12 GeV reach baryon densities comparable to neutron stars

CDR

Page 9: Hadronization and Quark Propagation in Nuclear Medium

Nuclear Medium Effects (I)

• EMC effect, shielding and anti-shielding

J. Ashman et al., Z. Phys. C57, 211 (1993)

J. Gomez et al., Phys. Rev. D49, 4348 (1994)

Page 10: Hadronization and Quark Propagation in Nuclear Medium

Polarized EMC effect

(Ian Cloet,

Wolfgang Bentz,

Tony Thomas)

p

A

gg

1

1

p

A

F

F

2

2

Page 11: Hadronization and Quark Propagation in Nuclear Medium

EMC Effect in PVDIS: CSV in Heavy Nuclei

Can be measured with SoLID (Cloet, Bentz,

and Thomas)

5%

Page 12: Hadronization and Quark Propagation in Nuclear Medium

Nuclear Medium Effects (II) Coulome Sum Rule

Probing a nucleon inside a nucleus

Possible modification of thenucleons’ property inside nuclei

Page 13: Hadronization and Quark Propagation in Nuclear Medium

E01-015

Precision Measurement of Coulomb Sum at q=0.5-1 GeV/c

Spokespersons: J. P. Chen, S. Choi and Z. E. MezianiPhD students: Y. Oh, H. Yao, X. Yan,

• New NaI detector for

background control

• Data taking last year

• Analysis well underway

• Expect preliminary results in a few

months

Page 14: Hadronization and Quark Propagation in Nuclear Medium

Nuclear Medium Effects (III)GE/GM with polarization transfer in 4He

Page 15: Hadronization and Quark Propagation in Nuclear Medium

Nuclear Medium Effects (IV)Color Transparency

• 12C(e,e’p)

Page 16: Hadronization and Quark Propagation in Nuclear Medium

Nuclear Medium Effects (V)

• Quark propagation in cold and hot matter

SIDIS A-A Collision

Eh = z~ 2 - 20 GeV Eh = pT ~ 2 – 20 GeV(HERMES/JLab) (RHIC)

Page 17: Hadronization and Quark Propagation in Nuclear Medium

Nuclei as Laboratories to Study Hadronization

What have we learned?

Page 18: Hadronization and Quark Propagation in Nuclear Medium

Nuclei: Laboratories to study Hadornization

• Use different size of nuclei to filter hadronization

Page 19: Hadronization and Quark Propagation in Nuclear Medium

SIDIS to study hadronization

• Quark propagation

Page 20: Hadronization and Quark Propagation in Nuclear Medium

Mechanism for Quark Propagation

• Non-perturbative in nature• Models: Accardi et al., Wang et al., Kopeliovich, et al.

Page 21: Hadronization and Quark Propagation in Nuclear Medium

Attenuation in SIDIS

• HERMES results help to sort out models and to understand mechanisms

• Energy loss (gluon bremsstrahlung)

Hadronization outside

• Pre-hadron absorption Color neutralization inside)

Page 22: Hadronization and Quark Propagation in Nuclear Medium

-Scaling

Pre-hadron absorption

> 0

Energy loss

< 0

Page 23: Hadronization and Quark Propagation in Nuclear Medium

PT - broadening

PT-broadening help to study production time, multiple scattering and beyond.

A, z, , Q2 dependence

Page 24: Hadronization and Quark Propagation in Nuclear Medium
Page 25: Hadronization and Quark Propagation in Nuclear Medium

PT-Broadening

Page 26: Hadronization and Quark Propagation in Nuclear Medium

Summary of Current Status

• HERMES results have made an impact in the study of a hadronization

• Clear attenuation in nuclear medium

• Scaling (prefer absorption mechanism?)

• PT-broadening: study production/formation length, multiple scattering, …

• Preliminary JLab CLAS 6 data: multi-variable binning

• What’s next?

Page 27: Hadronization and Quark Propagation in Nuclear Medium

Planned 12 GeV Measurements

CLAS12 (Hall B) and SHMS+HMS (Hall C)

Page 28: Hadronization and Quark Propagation in Nuclear Medium

12 GeV Upgrade Kinematical Reach

• Reach a broad DIS region • Precision SIDIS for

hadronization study

• Many other opportunities

(Valence quark, TMDs, GPDs)

Page 29: Hadronization and Quark Propagation in Nuclear Medium

Planned 12 GeV Measurements

• CLAS12 measurements (Will Brooks’ talk)

Large acceptance, extensive coverage

• HMS/SHMS measurements • High luminosity, small acceptance• E12-07-101, conditional approval• At selected kinematics, precision study

• What should be the choice of kinematics?

Page 30: Hadronization and Quark Propagation in Nuclear Medium

E12-07-101

• Overview: • SIDIS, A(e,e’/K+-)X• Targets: 1H, 2H, 12C, 64Cu and 184W• Q2: 2.5 – 6 GeV2, focus on high Q2

• = 6 GeV

• PT up to 0.8 GeV/c

• z ~ 0.5-0.9, focus on large z• Good PID for pions and Kaons

• Study Q2 dependence

PT/z dependence at high Q2

A dependence

Spokespersons: J. P. Chen, H. Lu, B. Norum, K. Wang

Page 31: Hadronization and Quark Propagation in Nuclear Medium

E12-07-101

• Accessible phase space with HMS/SHMS

Page 32: Hadronization and Quark Propagation in Nuclear Medium

PT-broadening

• PT broadening provides (almost direct) information on formation length (Kopeliovich model)

sensitive to z (at large z)

and A

Page 33: Hadronization and Quark Propagation in Nuclear Medium

E12-07-101 Projection

• Projected RM vs. z for + and proton on 3 targets

12C, 64Cu,184W

Page 34: Hadronization and Quark Propagation in Nuclear Medium

E12-07-101 Projection

• Projected RM vs. PT for 3 bins of z

Z=0.65, 0.75, 0.85

Page 35: Hadronization and Quark Propagation in Nuclear Medium

Discussion

• HMS/SHMS (High luminosity, small acceptance) measurements complementary to large acceptance CLAS12 measurements

• What should be the choice of kinematics?• need inputs

Page 36: Hadronization and Quark Propagation in Nuclear Medium

A new possibility

Solenoid Detector for SIDIS in Hall A

Page 37: Hadronization and Quark Propagation in Nuclear Medium

Solenoid detector for SIDIS at 11 GeVProposed for PVDIS at 11 GeV

FGEMx4

LGEMx4 LSGas Cherenkov

HG

Aerogel

GEMx2

SH

PS

Z[cm]

Y[cm

]

Yoke

Coil

3HeTarget

Page 38: Hadronization and Quark Propagation in Nuclear Medium

Power of SOLid for Sivers

Page 39: Hadronization and Quark Propagation in Nuclear Medium

Discussion• Large acceptance (~700 msr) and high luminosity (1037) provide

the unprecedented precision to map multi-variable dependence of nuclear SIDIS for hadronization study• RM and <PT>

• +, - and K+, K- and other particles

• Measure A, Q2, , PT and z dependence• Extract production length and formation length• Understand mechanisms: energy loss, absorption, … • Study current fragmentation and target fragmentation• Isolate different effects, differentiate models • Gain solid understanding of quark propagation in cold matter, forming a

baseline for hot matter study

• Shed light on fundamental processes of QCD: effects due to gluon field, sea (QCD vacuum) and confinement.

Page 40: Hadronization and Quark Propagation in Nuclear Medium

Summary

• Hadronization is a fundamental process of QCD Non-perturbative effect Related to QCD gluon field/sea/vacuum and confinement Nuclear medium is an idea lab to study hadronization

• Current status Our understanding is still primitive, a lot to be learned Many models, different mechanisms HERMES results provide valuable information and constraints to models CLAS 6 GeV started to provide precision measurements with multi-variables

• JLab 12 GeV SHMS/HMS, small acceptance with high luminosity complementary to CLAS12

large acceptance measurements• Needs input to optimize choice of kinematics

An opportunity for high-precision multi-variable measurements with SOLID (large acceptance and high luminosity)

• Help understanding fundamental QCD processes Lead to breakthrough ?