pvdis: 12 gev at jlabpvdis: 12 gev at jlabweb.mit.edu/pavi09/talks/souder_pvdis.pdf ·...

PVDIS: 12 GeV at JLabPVDIS: 12 GeV at JLab

For the SOLID Collaboration

June 23, 2009 PVDIS at 12 GeV 1

OUTLINEOUTLINE• PVDISPVDIS• Physics Potential

El t k li– Electroweak couplings– CSV– Higher Twist

• Apparatus• Conclusions


First Electron Parity ExperimentFirst Electron Parity Experiment

It was realized independently in the mid 70s at SLAC:It was realized independently in the mid 70s at SLACAPV in Deep Inelastic Scattering off liquid Deuterium: Q2 ~ 1 (GeV)2

10−4 ⋅ Q2APV ~ (GeV2)

This experiment convinced the world that the Z-boson violated parity


PV Asymmetries: Any Target

(gAegV

T +β gVegA

T)

•The couplings g depend on electroweak physics as well as on the weak vector and axial-vector hadronic currentweak vector and axial vector hadronic current •Both new physics at high energy scales as well as interesting features of hadronic structure come into play•A program with many targets and a broad kinematic range can


g y g guntangle the physics

Electron-Quark PhenomenologyAA

V

V

V A

Moller PV is insensitive to the Cij

C1u and C1d will be determined to high precision by Qweak, APV Cs

C2u and C2d are small and poorly known: one combination can be accessed in PV DIS

New physics such as compositeness, leptoquarks:

Deviations to C and C might be fractionally large


Deviations to C2u and C2d might be fractionally large

Deep Inelastic Scatteringe-

X

e-

Z* γ*APV =

GFQ2

2παa(x) + Y (y) b(x)[ ]

a(x) and b(x) contain quark

distribution functions fi(x)

iii fff ±≡±

a(x) =C1i Qi fi

+(x)i

∑Qi

2 fi+(x)

i∑

N X

y ≡1− ′ E / E b(x) =C2i Qi fi

− (x)i

∑Qi

2 fi+ (x)

i∑

x ≡ xBjorken

iii fff

For an isoscalar target like 2H, structure functions largely cancel in the ratio at high x

i i

a(x) =3

10(2C1u − C1d ) 1+

2s+

+ d+

⎛⎝⎜

⎞⎠⎟

6.0at high x

b(x) =3

10(2C2u − C2d )

uv + dv

u+ + d+

⎛⎝⎜

⎞⎠⎟

+L

At high x, APV becomes independent of x, W, with well-defined SM prediction for Q2 and y

( )10

( 1u 1d )u+ + d+⎝⎜ ⎠⎟

0

10 u + d⎝ ⎠1

C2q inaccessible in elastic scattering


DIS at high x (Approved)

2C2u − C2d 0 14 0 5% fractional precision on the2u 2d

2C1u − C1d

~ 0.14

δ 2C2u − C2d( )2C − C( ) ~ 5%

δ APV( )A

~ 0.5%

0.5% fractional precision on the asymmetry is needed!

2C2u − C2d( )APV

Feasible (in narrow kinematics) with existing JLab spectrometers.Feasible (in narrow kinematics) with existing JLab spectrometers.

Hall C HMS / SHMS spectrometers

JLab 11 GeV proposal: Conditional approvalPaschke, Reimer, Zheng et al.

• Experimental systematic errors challenging

• Averaged over large Q2, W, and x range


PVDIS with SOLID• Solenoid (from BaBar, CDF or CLEOII ) contains low energy backgrounds (Moller, pions, etc)trajectories measured after baffles • Fast tracking, particle ID, calorimetry, •and pipeline electronics• Precision polarimetry (0.4%)

• High Luminosity on LH2 & LD2

• Better than 1% errors for small bins• x range 0 25 0 75• x-range 0.25-0.75• W2 > 4 GeV2

• Q2 range a factor of 2 for each


• Moderate running times

Statistical Errors (%) vs KinematicsF SOLID S t tFor SOLID Spectrometer

Error bar σA/A (%)shown at center of binsin Q2, x

4 months at 11 GeV

2 months at 6.6 GeV

June 23, 2009 PVDIS at 12 GeV 9PAC34

Why do we need so many data i ?points?

• Possible new physicsPossible new physics– New interactions

Charge symmetry violation (CSV)– Charge symmetry violation (CSV)– Higher twist effects

Like neutron beta decay experiments:y pmany diverse physics topics


Sensitivity: C1 and C2 Plots

World’s data6 GeV

World s data

PVDIS

Qweak PVDISPrecision Data

Cs


Search for CSV in PV DIS•u-d mass difference•electromagnetic effects

up (x) = dn (x)?d p (x) = un (x)?

δu(x) = up (x) − dn (x)δd(x) = d p (x) − un (x)

•Direct observation of parton-level CSV would be very exciting!•Important implications for high energy collider pdfs•Could explain significant portion of the NuTeV anomalyp g f p f y

For APV in electron-2H DIS: dudu

AAPV

+−

=δδδ 28.0

PV duAPV +

Sensitivity will be further enhanced if u+d falls off more rapidly than δu-δd as x → 1


CSV Theory and Data

90% conf limitBroad minimum

(90% C.L.)

fully explains NuTeV

Analytic calculation

MRST PDF global with fit of CSV

doubles NuTeV deviationy

similar to global fit

Martin, Roberts, Stirling, Thorne [Eur Phys J C35, 325 (04)]:


Sensitivity with PVDISSensitivity with PVDIS

RCSV =δ APV x( )A ( )

= 0.28δu x( )− δd x( )

( ) d( )June 23, 2009 PVDIS at 12 GeV 14

CSV APV x( ) u x( )+ d x( )

Higher TwistSubject of recent workshop at Madison,

Wisconsin

≠

• APV sensitive to diquarks: ratio of weak to electromagnetic charge depends on amount of coherence (elastic He vs PVDIS)• Do diquarks have twice the x of single quarks?• If Spin 0 diquarks dominate, likely only 1/Q4 effects


Need Full PhenomenologyNeed Full Phenomenologyγγσ2 )1(22 FxyMFd

⎥⎤

⎢⎡ LRRFF σγγ →+ )1(γγσ

21 )2

1(22 FE

xyMyy

xyFdxdyd

EM

−−+∝⎥⎦

⎤⎢⎣

⎡

22 VMGd ⎤⎡

T

LRRFFσ

γγ =→+= )1(21

}])2

1(22{[22 21

2ZZ

AZ

FE

xyMyy

xyFgGdxdyd γγ

γ πασ

−−+−∝⎥⎦

⎤⎢⎣

⎡

2 AGd ⎤⎡ Th 5

])2([22 3

2Z

VZ

FyxgGdxdyd γ

γ πασ

−−∝⎥⎦

⎤⎢⎣

⎡

V

There are 5relevant structure

functions

EM

AZ

VZPV

BAσ

σσ γγ += EM

VZxa

σσγ=)(

EM

AZxbyf

σσ γ=)()(

BIG Small; use ν data


EM BIG Small; use ν data(Higher twist workshopat Madison, Wisconsin)

Best HT Data

F d i t th ti

Best HT Data

F2 dominates the cross section

Higher twist is clearlyHigher twist is clearlyseen at the PVDIS kinematics. What

can we add?can we add?

Analysis ofBlumlein and

BotcherJune 23, 2009 PVDIS at 12 GeV 17

Botcher

MRST Fits

F2(x,Q2)=F2(x)(1+D(x)/Q2) Q2=(W2-M2)/(1/x-1) Q2min=Q2(W=2)

x D(x) D(x) Q2min D/Q2

min(%) D/Q2min(%)

LO NNNLO LO NNNLO

2( ) 2( )( ( ) )

0.1-0.2 -.007 0.001 0.5 -14 20.2-0.3 -.11 0.003 1.0 -11 0.00.3-0.4 -.06 -0.001 1.7 -3.5 -0.50.4-0.5 .22 0.11 2.6 8 40.5-0.6 .85 0.39 3.8 22 100.6-0.7 2.6 1.4 5.8 45 24

MRST, PLB582,222 (04)

0.7-0.8 7.3 4.4 9.4 78 47

APV=APV(1+C(x)/Q2)


F2D(x): All x on Same ScaleF2D(x): All x on Same Scale

Order of DGLAPinfluences size

of HTof HT

Higher twistf ll l lfalls slowly

compared to PDF’sat large x.


D(x) versus xD(x) versus x

If C(x)~D(x), there is largesensirtivity al large x.


Why HT in PVDIS is SpecialWhy HT in PVDIS is Special∫ ⋅+ 4|)0()()0()(| xdeDjxJJxjDl xiqνμνμ

μν

Bjorken, PRD 18, 3239 (78)

xdeDVxVDlVV xiq 4|)0()(|∫ ⋅= νμ

∫∫

⋅∝

4|)0()(|

|)()()()(|

deDjxjDl

jjA

xiqνμμν

μν

( ) ( )dduuSdduuV γγγγ +=⇔−=

Wolfenstein,NPB146, 477 (78)

xdeDVxVDlVV q|)0()(|∫= μμν

( ) ( )dduuSdduuV μμμμμμ γγγγ +=⇔=

SSVV

SSCCVVCCA

dudu

1

)(31)( 1111 ++−

= Zero in QPMIsospin decomposition SSVV31+

xdeddxuxuDlSVSVSSVV xiq 4)0()0()()(|))(( ⋅∫∝+−=− νμμν γγ

Zero in QPMIsospin decompositionbefore using PDF’s

Higher-Twist valancequark-quark correlations

HT in F2 may be dominated by quark-gluon correlations

Vector-hadronic piece only


p y

Use ν data for small b(x) term.

Quark-Quark vs Quark-GluonQuark Quark vs Quark GluonWhat is a true

Parton Modelor

leading twistQuark-gluondiagram

quark-gluonoperator?

Di-quarksQuark-gluon operators

correspond to transverse momentum

QCD equationsof motion


transverse momentum

Test QuestionsTest Questions1. Which diagram is HT?2 Is the HT diagram qq or qg?2. Is the HT diagram qq or qg?

DGLAP Evolution


Diagrams (a)-(c) cancel in APV

Coherent Program of PVDIS S dStudy

Strategy: requires precise kinematics and broad range

⎥⎦

⎤⎢⎣

⎡+

−+= 2

23)1(11 x

QxAA CSVHT ββFit data to:

C(x)=β /(1 x)3

• Measure AD in NARROW bins of x, Q2 with 0.5% precision• Cover broad Q2 range for x in [0.3,0.6] to constrain HT

C(x)=βHT/(1-x)3

Cover broad Q range for x in [0.3,0.6] to constrain HT• Search for CSV with x dependence of AD at high x• Use x>0.4, high Q2, and to measure a combination of the Ciq’s

x y Q2

New Physics no yes noCSV yes no no

June 23, 2009 PVDIS at 12 GeV 24Higher Twist yes no yes

Other TargetsOther Targets• Hydrogen: d/uHydrogen: d/u• EMC effect

N Z l i• N≠Z nuclei


PVDIS on the Proton: d/u at High x

)(910)( xdxu +)(25.0)()(91.0)()(

xdxuxdxuxaP

++

≈

Deuteron analysis has largenuclear corrections (Yellow)

APV for the proton has no such corrections 3-month runsuch corrections

(complementary to BONUS)


The challenge is to get statistical and systematic errors ~ 2%

CSV in Heavy Nuclei: EMC EffectCSV in Heavy Nuclei EMC Effect

Additional possible

application of

Isovector-vector meanfield (Cloet

5%

application of SoLID

field. (Cloet, Bentz,

and Thomas)


SoLID SpectrometerSoLID SpectrometerGas Cerenkov

Shashlyk

June 23, 2009 PVDIS at 12 GeV 28Baffles

GEM’s

P. Bosted, J. P. Chen, E. Chudakov, A. Deur,

O. Hansen, C. W. de Jager,

L. El Fassi, R. Gilman, R. Ransome, E. Schulte

Rutgers

P. MarkowitzFlorida International

X Jiang

K. Grimm, K. Johnston, N. Simicevic, S. WellsLouisiana Tech

CollaborationO. Hansen, C. W. de Jager,

D. Gaskell, J. Gomez, D. Higinbotham, J. LeRose,

R. Michaels, S. Nanda, A. Saha, V. Sulkosky,

B. Wojtsekhowski

RutgersW. Chen, H. Gao, X. Qian,

Y. Qiang, Q. YeDuke University

K. A. Aniol C lif i St t

X. JiangLos Alamos

W. KorschUniversity of

Kentucky

Louisiana TechO. Glamazdin, R.

PomatsalyukNSC Kharkov

Institute for Physics and TechnologyJefferson Lab

P. A. Souder, R. Holmes Syracuse University

K. Kumar, D. McNulty, L. Mercado, R. Miskimen

California StateG. M. Urciuoli

INFN, Sezione di Roma

A. Lukhanin, Z. E. Meziani,

J. Erler Universidad Autonoma

de MexicoM. J. Ramsey-Musolf

University of

and TechnologyZ. G. Xiao

Tsinghua UniversityB.-Q. Ma, Y. J. Mao

Beijing UniversityX M Li J L S Zh

,U. Massachusetts

H. Baghdasaryan, G. D. Cates,D. Crabb, M. Dalton, D. Day,

N. Kalantarians, N. Liyanage, V. V. Nelyubin, B. Norum,

B. SawatzkyTemple University

P. M. King, J. RocheOhio University

E. Beise

University of Wisconsin

C. KeppelHampton UniversityH. Lu, X. Yan, Y. Ye, P. ZhuUniversity of Science

X. M. Li, J. Luan, S. ZhouChina Institute of

Atomic EnergyB. T. Hu, Y. W. Zhang,

Y. Zhangy , ,K. Paschke, S. Riordan,

O. A. Rondon, M. Shabestari,J. Singh, A. Tobias, K. Wang,

X. ZhengUniversity of Virginia

E. BeiseUniversity of

MarylandW. Bertozzi, S. Gilad,

W. Deconinck, S. Kowalski, B. Moffit

University of Science and Technology of

ChinaN. Morgan, M. PittVirginia Tech

J C P

Lanzhou UniversityC. M. Camacho, E. Fuchey,

C. Hyde, F. ItardLPC Clermont,

Université Blaise y gJ. Arrington, K. Hafidi,

P. E. Reimer, P. SolvignonArgonne

D. Armstrong, T. Averett, J. M. Finn

B. Moffit MIT

Benmokhtar, G. Franklin, B. Quinn

Carnegie MellonG Ron

J.-C. PengUniversity of Illinois

H. P. Cheng, R. C. Liu, H. J. Lu, Y. Shi

Huangshan University

PascalA. Deshpande

SUNY Stony BrookA. T. Katramatou,

G. G. Petratos


William and Mary P. Decowski

Smith College

G. RonTel Aviv University

T. HolmstromLongwood University

g yS. Choi, Ho. Kang, Hy. Kang

B. Lee, Y. OhSeoul National

University J. Dunne, D. Dutta

G. G. PetratosKent State University

J. W. MartinUniversity of

Winnipeg

STATUS and PLANSSTATUS and PLANS• Jan 2009: Conditional approvalJan. 2009: Conditional approval• Jan. 2010: Seek full approval

F ll 20 0 Di ’ i• Fall 2010: Director’s review• Spring 2011: Seek CD0


Kinematics at large xKinematics at large x


BafflesBaffles

Rates in detectors reducedby more than 10


Physics Resolution (%) vs D R l i d A lDetector Resolution and Angle

p θ

Q x2


ConclusionsConclusions• PVDIS addresses many physics topicsPVDIS addresses many physics topics

– Electroweak couplingsCSV at the quark level– CSV at the quark level

– Di-quarksd/ f th t– d/u for the proton

– Nuclear-induced CSVSO d li h• SOLID spectrometer can deliver the physics


Figure of Merit vs Scattering A lAngle


Lots of Pions at Low EnergiesLots of Pions at Low Energies

Need gas Cerenkovplus shower counterplus shower counter

with preradiator


Pion Rejection: Shashlik DetectorPion Rejection Shashlik Detector

Total Pion Signal Epreshower/Etotal


g Epreshower/Etotal

pvdis: 12 gev at jlabpvdis: 12 gev at jlabweb.mit.edu/pavi09/talks/souder_pvdis.pdf ·...

Documents