What Have We Learned from Deep ? Xiaochao Zheng Univ. of Virginia October 31, 2011

– Introduction – the four interactions, the Standard Model, and the role of electron scattering

How is the nucleon energy shared among ? How are quarks polarized inside the nucleon? How do quarks behave in neutral weak interactions?

– Summary

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 1/57 What Is the World Made of?

Mass of the nucleon: 1 GeV ~ 10-10 Joules ~ (5x10-15m)-1 = (5 fm)-1 ~ (10-24 seconds)-1 ~ 10-24 grams, (10-35 of Empire State Building)

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 2/57 And How Do They Interact?

Electromagnetic 10-2 SU(2)xU(1) Weak 10-5 at low E group theory Strong 10-1~100 SU(3) QCD Gravitational 10-38 General relativity strong SU(3) Color

SU(2) EW ? ?

U(1) EW Gravitational weak

(250 GeV ~ 5 x 1014 GeV ~ 2.4 x 1018 GeV)?

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 3/57 And How Do They Interact?

Electromagnetic 10-2 SU(2)xU(1) Weak 10-5 at low E group theory Strong 10-1~100 SU(3) QCD Gravitational 10-38 General relativity

Electromagnetic Interaction – Interaction of (QED) Carried by photons: massless, spin-1, electrically neutral Well understood, higher order processes correctable, tested to 10-9 accuracy

vs.

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 4/57 And How Do They Interact?

Electromagnetic 10-2 SU(2)xU(1) Weak 10-5 at low E group theory Strong 10-1~100 SU(3) QCD Gravitational 10-38 General relativity

Weak Interaction – Interaction of Weak Charges Massive spin-1 bosons Z0, W±; Appears to be weak at low energies; Unified with electromagnetic interaction via the “mixing” of SU(2)xU(1); Violates parity symmetry; Tested to good precision, but is challenged by experiments (neutrino oscillations, etc.)

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 5/57 And How Do They Interact?

Electromagnetic 10-2 SU(2)xU(1) Weak 10-5 at low E group theory Strong 10-1~100 SU(3) QCD Gravitational 10-38 General relativity

Weak Interaction – Interaction of Weak Charges

SU(3) Color (Grand Unification) SU(2) EW ? ? (Theory of Everything)

U(1) EW Gravitational

(250 GeV ~ 5 x 1014 GeV ~ 2.4 x 1018 GeV)? prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 6/57 And How Do They Interact?

Electromagnetic 10-2 SU(2)xU(1) Weak 10-5 at low E group theory Strong 10-1~100 SU(3) QCD Gravitational 10-38 General relativity

Weak Interaction – Interaction of Weak Charges

Indirect searchSU(3) for Color (signs of) Beyond Direct search the Standard (LHC...) 7 TeV Model Physics, such ? ? as tiny changesSU(2) in EW ? ? interaction strengths, Gravitational eV-GeV U(1) EW Gravitational

(250 GeV ~ 5 x 1014 GeV ~ 2.4 x 1018 GeV)? prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 7/57 And How Do They Interact?

Electromagnetic 10-2 SU(2)xU(1) Weak 10-5 at low E group theory Strong 10-1~100 SU(3) QCD Gravitational 10-38 General relativity

Strong Interaction – Interaction of 3 Color Charges (QCD) Gluons: massless, spin-1, but carries colors Strong coupling strength Higher order processes gives: 1.5 small couplings at high energies (asymptotic freedom, perturbative QCD) 1.0

large couplings S>1 at long distances (>0.1fm), calculation very difficult 0.5 Colored objects do NOT exist in Nature – experiments with free quarks and gluons not 0.0 possible; Color confinement cannot be 0 0.05 0.10 0.15 0.20 r(10-15m) computed in QCD (yet). prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 8/57 The Role of Electron-Nucleon Scattering

Electromagnetic 10-2 SU(2)xU(1) Weak 10-5 at low E group theory Strong 10-1~100 SU(3) QCD Gravitational 10-38 General relativity

Electron beam = a source of photons and Z0's 's: probe structure of the nucleon – how do quarks form the nucleon energy, mass, spin … … via strong interactions? Z's: parity violation electron scattering

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 9/57 What is the Nucleon Made of?

The simple model of

Gell-Mann (Nishijima) 1961-1964/1969

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 10/57 Exploring Nucleon Structure Using Electron Scattering

k '=E ' ,k ' W 2 =P' 2 t q= ,q

Q 2=−q 2

k= E ,k P=  M, 0 

x The inclusive scattering “” describes the probability of being scattered to E' and Ω.

d 2 σ = σ αF  Q 2 ,ν  +βF  Q 2 ,ν  d  dE' Mott[ 1 2 ]

For point-like target prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 11/57 Exploring Nucleon Structure Using Electron Scattering

k '=E ' ,k ' W 2 =P' 2

q= ,q

Q 2=−q 2

k= E ,k P=  M, 0 

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 12/57 Exploring Nucleon Structure Using Electron Scattering Elastic, quasi-elastic, resonances, deep inelastic

 (Quasi-) elastic – the nucleus (nucleon) appears as a rigid body

 Resonance region – quarks inside the nucleon excited to resonance modes

 Deep Inelastic Scattering (DIS): start to see deep inside the nucleon (individual constituents)

(highly non-pertubative, phenomenology models)

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 13/57 Exploring Nucleon Structure Using Electron Scattering Elastic, quasi-elastic, resonances, deep inelastic

 (Quasi-) elastic – the nucleus (nucleon) appears as a rigid body

 Resonance region – quarks inside the nucleon excited to resonance modes

 Deep Inelastic Scattering (DIS): start to see deep inside the nucleon (individual constituents)

(highly non-pertubative, phenomenology models)

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 14/57 Exploring Nucleon Structure Using Electron Scattering Elastic, quasi-elastic, resonances, deep inelastic

 (Quasi-) elastic – the nucleus (nucleon) appears as a rigid body

 Resonance region – quarks inside the nucleon excited to resonance modes

 Deep Inelastic Scattering (DIS): Start to see deep inside the nucleon (individual constituents)

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 15/57 Virtual photon compared to (real, visible) photon

k '=E ' ,k ' W 2 =P' 2 t q= ,q

Q 2=−q 2

k= E ,k P=  M, 0  Focus (spatial resolution): 1/Q2 x Time exposure 1/

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 16/57 “Resonance” “Elastic”

“Deep Inelastic”

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 17/57 From Electron Deep Inelastic Scattering F F 2 2

( ( 10 3.5 x x , , Q Q

2 9 2 ) )

+ + 3 c c ( 8 ( x x P ) )

2.5 h

7 y s .

6 R 2 e v . 5 D

1.5 6 4 6 ,

0 1

3 0

1 0 0

2 1

( 2

0.5 0

1 0 2 ) 0 0 2 0.1 1.0 10 102 103 104 105 106 0.1 1.0 10 10 Q2(GeV2) Q2(GeV2)

shifted according to Q2/

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 18/57 From Electron Deep Inelastic Scattering F 2

( 10 “scaling”: x , Q

2 9

) What we observe is + c independent of the resolution ( 8 x ) of the photon probe (1/Q2) 7

6 5 the constituents must be 4 point-like particles, spaced far apart. 3

2

1

0 0.1 1.0 10 102 103 104 105 106 Q2(GeV2)

Friedman, Kendall, Taylor et al. 1968/1990

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 19/57 From Electron Deep Inelastic Scattering F 2

( 10 x

, “scaling violation” Q

2 9 ) 2 + Log(Q ) dependence c

( 8 x ) 7

6 5 the quarks are weakly 4 interacting inside the nucleon “Asymptotic Freedom” 3 2 4π 2 α  Q = S 2 2  11−2n f /3 ln  Q / Λ  1

0 t Hooft 1972/1999 0.1 1.0 10 102 103 104 105 106 Gross, Wilczek, Politzer 1972/2004 Q2(GeV2)

Agree very well with perturbative QCD calculations

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 20/57 How Does the (inside of) Nucleon Look Like?

The simple quark model of hadrons

Gell-Mann (Nishijima) 1961/1964/1969

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 21/57 Feynman's Quark Parton Model

In DIS, x=Q2/(2M) P(nucleon) -> ∞

0 1/3 1 x each quark carries x-fraction of P;

0 1/3 1 x

Parton distribution function q(x): Probability to find the u, d, s... quarks carrying x-fractionprepared as ppt file on ofdaisy withthe openoffice.org3 nucleon'sX. Zheng, Octobermomentum 2011, Colloqium at UVa 22/57 What is the Probability to find a Quark or Gluon at x? A

. xq(x) D .

M a r t i n e t a l ,

E u r .

P h y s .

J .

C 6 3 ,

1 8 9

( 2 0 0 9 ) x After four decades of DIS experiments, we know reasonably well how quarks carry the nucleon energy. However, our study of the nucleon has just started......

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 23/57 Adding one more Degree of Freedom:

The SPIN

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 24/57 Spin and Polarized Deep Inelastic Scattering

Spin describes particles' intrinsic angular momentum;

Spin follows rules of angular momentum;

Spin allows magnetic moment — a small magnet, interacts with magnetic field (wide applications:)

Fundamental interactions are often spin- dependent

Scattering cross section is spin-dependent (imaging throwing two small magnets together)

vs.

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 25/57 How Are Quarks Polarized Inside the Nucleon?

P(nucleon) -> ∞

Spin(nucleon) how does each quark align its spin, while carrying x- fraction of P?

Polarized parton distribution function q(x): u(x)/u(x), d(x)/d(x), u(x)/u(x), d(x)/d(x) ......

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 26/57 Question: Do Data Agree with (QCD) Calculations?

We need to work with Valence Quarks! (large x)

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 27/57 Predictions for Valence Quark Polarizations

1 1 1 ∣p∣= ∣u  ud  ∣ ∣u  ud  ∣− ∣u   ud  ∣ 2 00 18 10 3 11 1 2 − ∣d   uu ∣−  ∣d   uu  ∣ 3 10 3 11

based on the symmetry of the 3 quarks' wavefunctions:

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 28/57 Predictions for Valence Quark Polarizations

 1  1  1  ∣p ∣= ∣u  ud 00∣ ∣u  ud 10∣− ∣u  ud 11∣ 2 18 3 “spin asymmetries” 1 2 − ∣d   uu ∣−  ∣d   uu  ∣ 3 10 3 11 Model n p u/u d/d A1 A1

SU(3) flavor (u,d,s) + 2/3`� # � #### �� � ^ ��Ȱ ############## -1/3 0 5/9 SU(2) spin Quark-diquark + 1 -1/3 1 1 hyperfine interaction pQCD + neglecting 1 1 1 1 quark orbital motion 2 2 −1 2   ux  d x p 3 3 A x= 1 2 2 −1 2   ux  d x prepared as ppt file3 on daisy with openoffice.org33 X. Zheng, October 2011, Colloqium at UVa 29/57 It's not Easy To Probe the Valence Quarks

high Q2 photons “live” shorter

Large x + high Q2 = doubly small chance to find the quarks = need high intensity beam and very dense targets (high luminosity)

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 30/57

Staff: ~650 User community: ~1300 Unique superconducting radio frequency accelerator provides the highest polarized luminosity of the world  334/249 PhDs (~1/3 of US PhDs in Nuclear Physics) A B C  Energy: 6 GeV(1995-present), 12 GeV (2013) prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 31/57 Spin Asymmetries and Valence Quark Polarizations

Before JLab pQCD di-quark di-quark pQCD SU(6) SU(6)

pQCD pQCD

n

1

A

di-quark

n

o r SU(6) t di-quark

u

e n SU(6)

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 32/57 Spin Asymmetries and Valence Quark Polarizations

) with JLab 6 GeV data 6

pQCD X 0 .

Z 0 1.0 (HHC)

h 2

di-quark e

n

g S

e t

A di-quark pQCD

a

L l

0.5 . C ,

( P

R

L n SU(6) SU(6)

9 o

2 t ,

o

0 r 0 1

2 p 0 0 4

X. Zheng et al. (2004) (

) 1.0 2 0

4 0

0 4 )

0 ;

pQCD pQCD P

2 R

(HHC) C 7 A 0.5 di-quark 0

l ,

l di-quark 0

a 6

SU(6) 5

H 2

( 0

7

n 0 ( 2

o 0

r 0

t 4

u SU(6) )

e -0.5n

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 33/57 What can we learn from the valence quark polarizations?

q/q describes how the quark is polarized along the nucleon spin

pQCD+neglecting quark orbital motion: the quark carrying x~1 fraction of the nucleon's momentum should also carries the nucleon's spin (pQCD-based); the remaining energy is small (1-x), so quark's orbital motion is negligible.

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 34/57 What can we learn from the valence quark polarizations?

q/q describes how the quark is polarized along the nucleon spin

pQCD+neglecting quark orbital motion: the quark carrying x~1 fraction of the nucleon's momentum should also carries the nucleon's spin (pQCD-based); the remaining energy is small (1-x), so quark's orbital motion is negligible.

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 35/57 What can we learn from the valence quark polarizations?

q/q describes how the quark is polarized along the nucleon spin

pQCD+neglecting quark orbital motion: the quark carrying x~1 fraction of the nucleon's momentum should also carries the nucleon's spin (pQCD-based); the remaining energy is small (1-x), so quark's orbital motion is negligible.

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 36/57 What can we learn from the valence quark polarizations?

q/q describes how the quark is polarized along the nucleon spin

pQCD+neglecting quark orbital motion: the quark carrying x~1 fraction of the nucleon's momentum should also carries the nucleon's spin (pQCD-based); the remaining energy is small (1-x), so quark's orbital motion is negligible.

The quark orbital motion is NOT negligible even in the highly energetic, large x region – How? Does strong interaction force the down quark to align opposite to the spin? Is the diquark hyperfine interaction strong enough to flip the down quark?

TheThe JLabJLab HallHall AA datadata werewere quotedquoted inin thethe 20072007 longlong rangerange planplan ofof thethe USUS NuclearNuclear ScienceScience AdvisoryAdvisory CommitteeCommittee asas oneone ofof thethe “most“most importantimportant accomplishmentsaccomplishments sincesince thethe 20022002 LRP”;LRP”; prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 37/57 Including the Quark Orbital Angular Momentum?

H. Avakian, S. Brodsky, A. Deur, F. Yuan, Phys. Rev. Lett.99:082001(2007)

light-cone quark/diquark model X. Chen, Y. Mao, B.-Q. Ma, Nucl. Phys. A 759, 188 (2005)

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 38/57 (The Most) Frequently Asked Question

“Come on, you call x=0.6 'valence quark region'? You need higher x than that ! ”

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 39/57 The Planned JLab 12 GeV Measurement Hall A spokespeople: Hall C spokespeople: G.D. Cates, N.Liyanage, G. Rosner, J.P.Chen, Z.E.Meziani, G.D. Cates, B.Wojtsekhowski, X. Zheng; X.Zheng; Student: Jie Liu (UVa) Approved for 35 days, rated A Approved for 23 days, rated A- n n A1 A1

Flagship of the 12 GeV Upgrade

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 40/57 Perhaps Once We Understand the Rules of Spin in Strong Interactions

Sure ! After all, Morning ! Can I I have this 150- ride with you to mpg spinergy car work today? thanks to your work !

vehicle using spinergy physicists

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 41/57 (Neutral) Weak Interaction in DIS (Parity Violating DIS, or PVDIS)

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 42/57 What is Parity Violation? The parity symmetry: the physical laws behind all phenomena must be the same as those behind their mirror images; However this symmetry is broken in weak interactions. Yang, Lee (Wu) 1957/1957

In the Standard Model, weak interaction current = V(vector) minus A(axial-vector)

Parity violation is from the V-A (-V)-A cross products V x A

Z0

V-A (-V)-A

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 43/57 Parity Violating Electron Scattering Weak observable in electron scattering — parity violating asymmetries (APV) (polarized beam + unpolarized target)

R L

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 44/57 Parity Violating Electron Scattering Weak observable in electron scattering — parity violating asymmetries (APV) (polarized beam + unpolarized target)

R L

180o

L

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 45/57 Parity Violating Electron Scattering Weak observable in electron scattering — parity violating asymmetries (APV) (polarized beam + unpolarized target)

vs. R L 2 MZ= 91 GeV 10000±1 events 10000 events

r l 2 σ −σ Q 2 A = 2 LR ALR≡ r l ≈ 2 ≈120 ppm at Q =1  GeV /c  σ +σ M Z

M= 0

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 46/57 Parity Violation in Deep Inelastic Scattering

A V electron PV ~

quark V A C 1q C2q

2 a(x), b(x) contain quark A PV ∝Q [ a xY  yb x] distributions Y(y) contains kinematics

PVDIS can be used to access C1,2qs SLAC E122 (1978): The first parity violation electron scattering experiment, also the only PVDIS until 2009 Established Weinberg & Salam's specific mixing of SU(2) and U(1) as the theory of electroweak unification.

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 47/57 Parity Violation in Deep Inelastic Scattering

A V electron PV ~

quark V A

2 a(x), b(x) contain quark A PV ∝Q [ a xY  yb x] distributions Y(y) contains kinematics

PVDIS can also access the nucleon structure beyond the simple parton model

Require careful planning!

6 GeV (moderate precision, two kinematics) – accessing the C2q 12 GeV (high precision, wide kinematics) – accessing both.

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 48/57 The 6 GeV JLab PVDIS Measurement (E08-011) Spokespeople: P.E. Reimer, R. Michaels, X. Zheng Grad. Students: Kai Pan (MIT), Diancheng Wang (UVa), Xiaoyan Deng (UVa) Postdoc: Ramesh Subedi (Hall-A Collaboration Experiment, A- rating)

Ran successfully from Oct-Dec. 2009 in JLab Hall A; 105A, 6 GeV, 90% polarized beam, helicity flip every 33msec; 20-cm liquid deuterium target; ~500kHz scattered electron events with high pion background;

2 2 Measure APV at Q =1.10 and 1.90 GeV to 3% and 4% (stat.), systematic uncertainties are smaller. Analysis on-going. From the 1.90 GeV2 point, expect to achieve factor of

5 improvement on 2C2u-C2d.

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 49/57 It's not easy to count electrons! — Our customized fast counting DAQ with online particle identification

total cost: $200k

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 50/57 Statistical Quality of Data

purely statistical = pure Gaussian

Q2=1.1 Q2=1.9

asymmetry of electron counts within 66msec-long beam helicity L/R pairs (in ppm)

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 51/57 Quark Weak Neutral Couplings C1,2q all are 1  limit with recent PVES data and Qweak SAMPLE without JLab data (elastic) 1.75

1.5 SLAC/ 1.25 Prescott 1.0

C 0.75 2 u +

C 0.5 2 d 0.25

(elastic) 0

0.25 best fit of -0.5 Particle Data Group -0.75 - 0.5 - 0.25 0 0.25 0.5

C2u­C2d

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 52/57 Quark Weak Neutral Couplings C1,2q all are 1  limit with recent PVES data and Qweak SAMPLE (elastic) with JLab 6 GeV 1.75

1.5 SLAC/ 1.25 Prescott 1.0

C 0.75 2 u +

C 0.5 2 d 0.25

(elastic) 0

0.25

-0.5

-0.75 - 0.4 - 0.2 0 0.2 0.4

C2u­C2d

PVDIS @ JLab 6 GeV: potential to improve C2q knowledge if hadronic effects are small. prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 53/57 Coherent PVDIS Program with SoLID @ 11 GeV Fully approved, 180 days, rated A A 20M$ device

““SoLID”SoLID” spectrometerspectrometer

Other PVDIS physics topics: sinW, charge symmetry violation, diquarks, d/u of the proton (90 days);

Also Semi-inclusive DIS. prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 54/57 Thanks to Everyone Working (Worked) with Me

PVDIS analysis log #77 Students: Huaibo Ding (THU, China) Xiaoyan Deng (UVa) Diancheng Wang (UVa) Kai Pan (MIT) Jie Liu (UVa)

Postdocs: Ramesh Subedi Zhiwen Zhao

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 55/57 Thanks to Everyone Working (Worked) with Me

PVDIS analysis log #77

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 56/57 Summary My involvement: Sponsored by We have learned a lot from deep inelastic scattering experiments: how quarks and gluons NSF Nuclar Physics (2007-2009) share the energy of the nucleon DoE Early Career And how quarks are polarized inside the nucleon: (2010-2014) – The 6 GeV results from JLab showed the importance (sole) PhD student, of the quark orbital motion 2000-03 – several 12 GeV measurements have been planned (flagship experiments of the 12 GeV Upgrade); spokesperson of 2 neutron Parity Violation DIS experiments can access the experiments quark neutral weak coupling + the structure of the nucleon beyond the simple parton model: leading spokesperson, 2003-2005-2008- – The 6 GeV PVDIS measurement at JLab was 2009-present completed successfully in Dec 2009, data to be released before 2012; Core group, leading simulation and – The 12 GeV SoLID program is being planned. calorimeter R&D

prepared as ppt file on daisy with openoffice.org3 X. Zheng, October 2011, Colloqium at UVa 57/57