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Precision Measurement of Parity-violation in Deep Inelastic - - PowerPoint PPT Presentation

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Precision Measurement of Parity-violation in Deep Inelastic Scattering Over a Broad Kinematic Range P. A. Souder July 28, 2010 PVDIS 1 Outline Physics potential Standard Model Test Charge Symmetry Violation (CSV) Higher Twist

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SLIDE 1

Precision Measurement of Parity-violation in Deep Inelastic Scattering Over a Broad Kinematic Range

  • P. A. Souder

July 28, 2010 PVDIS 1

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SLIDE 2

July 28, 2010 PVDIS 2

Outline

  • Physics potential

– Standard Model Test – Charge Symmetry Violation (CSV) – Higher Twist – d/u for the Proton

  • New Solenoidal Spectrometer (SoLID)
  • Polarimetry
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SLIDE 3

July 28, 2010 PVDIS 3

  • The couplings gT depend on electroweak physics as well as on the

weak vector and axial-vector hadronic current

  • For PVDIS, both new physics at high energy scales as well as

interesting features of hadronic structure come into play

  • A program with a broad kinematic range can untangle the physics

(gA

egV T + gV egA T)

PV Asymmetries: Any Target and Any Scattering Angle

Forward Backward

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SLIDE 4

July 28, 2010 PVDIS 4

PVDIS: Electron-Quark Scattering

C1u and C1d will be determined to high precision by Qweak, APV Cs C2u and C2d are small and poorly known:

  • ne combination can be accessed in PV DIS

A V V A

Moller PV is insensitive to the Cij

Consider ฀  f1 f

1  f2 f 2

฀  f1f2  f1f2

  • r

gij’s for all f1f2 combinations and L,R combinations

Many new physics models give rise to neutral ‘contact’ (4-Fermi) interactions: Heavy Z’s, compositeness, extra dimensions…

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SLIDE 5

July 28, 2010 PVDIS 5

New combination of: Vector quark couplings C1q Also axial quark couplings C2q

Deep Inelastic Scattering

i i i

f f f  

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

b(x)  3 10 (2C2u  C2d) uv  dv u  d       

a(x) = C1i Qi fi

+(x) i

Qi

2 fi +(x) i

e- N X e- Z* * ฀  y 1  E /E b(x)  C2iQi fi

(x) i

Qi

2 fi (x) i

฀  x  xBjorken

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

Sensitive to new physics at the TeV scale

฀ 

a(x)  3 10 (2C1u  C1d) 1 2s u  d      

6 .

APV  GFQ2 2 a(x) Y(y) b(x)

 

1

at high x

a(x) and b(x) contain quark distribution functions fi(x)

PVDIS: Only way to measure C2q

Unknown radiative corrections for coherent processes

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SLIDE 6

July 28, 2010 PVDIS 6

Sensitivity: C1 and C2 Plots

Cs PVDIS Qweak PVDIS

World’s data Precision Data

6 GeV

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SLIDE 7

July 28, 2010 PVDIS 7

Search for CSV in PV DIS

Sensitivity will be further enhanced if u+d falls off more rapidly than u-d as x  1

  • measure or constrain higher twist effects at x ~ 0.5-0.6
  • precision measurement of APV at x → 0.8 to search for CSV

Strategy:

  • u-d mass difference
  • electromagnetic effects
  • Direct observation of parton-level CSV would be very exciting!
  • Important implications for high energy collider pdfs
  • Could explain significant portion of the NuTeV anomaly

฀  up(x)  dn(x)? d p(x)  un(x)?

For APV in electron-2H DIS: d u d u A A

PV PV

      28 .

฀  u(x)  up(x)  dn(x) d(x)  d p(x)  un(x)

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SLIDE 8

July 28, 2010 PVDIS 8

Sensitivity with PVDIS

RCSV  APV x

 

APV x

   0.28u x

 d x  

u x

  d x  

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SLIDE 9

July 28, 2010 PVDIS 9

Need Full Phenomenology

 

2 1 2

) 2 1 ( 2 2 F E xyM y y xyF dxdy d

EM

         

}] ) 2 1 ( 2 2 { [ 2 2

2 1 2 Z Z A V Z

F E xyM y y xyF g G dxdy d

  

            

] ) 2 ( [ 2 2

3 2 Z V A Z

F y x g G dxdy d

 

          

T L

R R F F  

 

    ) 1 (

2 1

EM A Z V Z PV B

A   

  

EM V Z

x a     ) (

EM A Z

x b y f     ) ( ) (

There are 5 relevant structure functions

BIG

Small; use ν data (Higher twist workshop at Madison, Wisconsin)

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SLIDE 10

July 28, 2010 PVDIS 10

Why HT in PVDIS is Special

x d e D V x V D l VV

x iq 4

| ) ( ) ( |

  

 

 

 

4 4

| ) ( ) ( | | ) ( ) ( ) ( ) ( | d e D j x j D l x d e D j x J J x j D l A

x iq x iq        

   

d d u u S d d u u V

     

        

SS VV SS C C VV C C A

d u d u

3 1 ) ( 3 1 ) (

1 1 1 1

    

x d e d d x u x u D l S V S V SS VV

x iq 4

) ( ) ( ) ( ) ( | ) )( (

    

  

 

Bjorken, PRD 18, 3239 (78) Wolfenstein, NPB146, 477 (78)

Zero in QPM

Higher-Twist valance quark-quark correlations HT in F2 is dominated by quark-gluon correlations Vector-hadronic piece only

Next use CVC (deuteron only) Start with Lorentz Invariance

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SLIDE 11

July 28, 2010 PVDIS 11

Quark-Quark vs Quark-Gluon

Parton Model

  • r

leading twist Di-quarks Quark-gluon diagram What is a true quark-gluon

  • perator?

Quark-gluon operators correspond to transverse momentum QCD equations

  • f motion

u u d u

Might be computed

  • n the lattice

PVDIS is the

  • nly known way

to isolate quark-quark correlations

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SLIDE 12

July 28, 2010 PVDIS 12

Statistical Errors (%) vs Kinematics

4 months at 11 GeV 2 months at 6.6 GeV Error bar σA/A (%) shown at center of bins in Q2, x Strategy: sub-1% precision over broad kinematic range for sensitive Standard Model test and detailed study of hadronic structure contributions

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SLIDE 13

July 28, 2010 PVDIS 13

Coherent Program of PVDIS Study

  • 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
  • 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

Strategy: requires precise kinematics and broad range

x y Q2 New Physics no yes no CSV yes no no Higher Twist yes no yes

         

2 2 3

) 1 ( 1 1 x Q x A A

CSV HT

 

Fit data to: C(x)=βHT/(1-x)3

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SLIDE 14

July 28, 2010 PVDIS 14

PVDIS on the Proton: d/u at High x

Deuteron analysis has large nuclear corrections (Yellow) APV for the proton has no such corrections (complementary to BONUS) The challenge is to get statistical and systematic errors ~ 2%

) ( 25 . ) ( ) ( 91 . ) ( ) ( x d x u x d x u x aP   

3-month run

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SLIDE 15

July 28, 2010 PVDIS 15

CSV in Heavy Nuclei: EMC Effect

Additional possible application of SoLID Isovector- vector mean

  • field. (Cloet,

Bentz, and Thomas)

5%

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SLIDE 16

July 28, 2010 PVDIS 16

SoLID Spectrometer

Baffles GEM’s Gas Cerenkov Shashlyk

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SLIDE 17

July 28, 2010 PVDIS 17

Layout of Moller and PVDIS

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SLIDE 18

July 28, 2010 PVDIS 18

Access to the Detectors

  • End Cap rolls

backward along the beam line on Hilman Rollers

  • 342 metric tons

for both end caps with baffles installed

  • Must allow for

5% rolling resistance

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SLIDE 19

July 28, 2010 PVDIS 19

Baffle geometry and support

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SLIDE 20

July 28, 2010 PVDIS 20

Error Projections for Moller Polarimetry

Table from MOLLER director’s review by E. Chudakov

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SLIDE 21

July 28, 2010 PVDIS 21

Summary of Compton Uncertainties

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SLIDE 22

July 28, 2010 PVDIS 22

Error Budget in %

Statistics 0.3 Polarimetry 0.4 Q2 0.2 Radiative Corrections 0.3 Total 0.6

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SLIDE 23

July 28, 2010 PVDIS 23

  • P. Bosted, J. P. Chen,
  • E. Chudakov, A. Deur,
  • O. Hansen, C. W. de Jager,
  • D. Gaskell, J. Gomez,
  • D. Higinbotham, J. LeRose,
  • R. Michaels, S. Nanda,
  • A. Saha, V. Sulkosky,
  • B. Wojtsekhowski

Jefferson Lab

  • P. A. Souder, R. Holmes

Syracuse University

  • K. Kumar, D. McNulty,
  • L. Mercado, R. Miskimen
  • U. Massachusetts
  • H. Baghdasaryan, G. D. Cates,
  • D. Crabb, M. Dalton, D. Day,
  • N. Kalantarians, N. Liyanage,
  • V. V. Nelyubin, B. Norum,
  • K. Paschke, S. Riordan,
  • O. A. Rondon, M. Shabestari,
  • J. Singh, A. Tobias, K. Wang,
  • X. Zheng

University of Virginia

  • J. Arrington, K. Hafidi,
  • P. E. Reimer, P. Solvignon

Argonne

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

William and Mary

  • P. Decowski

Smith College

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

Rutgers

  • W. Chen, H. Gao, X. Qian,
  • Y. Qiang, Q. Ye

Duke University

  • K. A. Aniol

California State

  • G. M. Urciuoli

INFN, Sezione di Roma

  • A. Lukhanin, Z. E. Meziani,
  • B. Sawatzky

Temple University

  • P. M. King, J. Roche

Ohio University

  • E. Beise

University of Maryland

  • W. Bertozzi, S. Gilad,
  • W. Deconinck, S. Kowalski,
  • B. Moffit

MIT

Benmokhtar, G. Franklin,

  • B. Quinn

Carnegie Mellon

  • G. Ron

Tel Aviv University

  • T. Holmstrom

Longwood University

  • P. Markowitz

Florida International

  • X. Jiang

Los Alamos

  • W. Korsch

University of Kentucky

  • J. Erler

Universidad Autonoma de Mexico

  • M. J. Ramsey-Musolf

University of Wisconsin

  • C. Keppel

Hampton University

  • H. Lu, X. Yan, Y. Ye, P. Zhu

University of Science and Technology of China

  • N. Morgan, M. Pitt

Virginia Tech

J.-C. Peng

University of Illinois

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

Huangshan University

  • S. Choi, Ho. Kang, Hy. Kang B.

Lee, Y. Oh

Seoul National University

  • J. Dunne, D. Dutta

Mississippi State

  • K. Grimm, K. Johnston,
  • N. Simicevic, S. Wells

Louisiana Tech

  • O. Glamazdin, R. Pomatsalyuk

NSC Kharkov Institute for Physics and Technology

  • Z. G. Xiao

Tsinghua University

B.-Q. Ma, Y. J. Mao

Beijing University

  • X. M. Li, J. Luan, S. Zhou

China Institute of Atomic Energy

  • B. T. Hu, Y. W. Zhang,
  • Y. Zhang

Lanzhou University

  • C. M. Camacho, E. Fuchey,
  • C. Hyde, F. Itard

LPC Clermont, Université Blaise Pascal

  • A. Deshpande

SUNY Stony Brook

  • A. T. Katramatou,
  • G. G. Petratos

Kent State University

  • J. W. Martin

University of Winnipeg

PVDIS Collaboration

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SLIDE 24

July 28, 2010 PVDIS 24

Summary

  • The physics is varied and exciting.

– Excellent sensitivity to C2u and C2d. – Test CSV at quark level. – Unique window on higher twists.

  • We will build a novel apparatus (with many
  • ther possible applications, eg. SIDIS)
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SLIDE 25

July 28, 2010 PVDIS 25

฀  n n  e2B/ kT  1014

Atomic Hydrogen For Moller Target

Moller polarimetry from polarized atomic hydrogen gas, stored in an ultra-cold magnetic trap

  • Tiny error on polarization
  • Thin target (sufficient rates but

no dead time)

  • 100% electron polarization
  • Non-invasive
  • High beam currents allowed
  • No Levchuk effect
  • E. Chudakov and V. Luppov, IEEE Transactions on

Nuclear Science, v 51, n 4, Aug. 2004, 1533-40

Brute force polarization 10 cm, ρ = 3x1015/cm3 in B = 7 T at T=300 mK

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SLIDE 26

July 28, 2010 PVDIS 26

High Precision Compton

At high energies, SLD achieved 0.5%. Why do we think we can do better?

  • SLD polarimeter near interaction

region - background heavy

  • No photon calorimeter for production
  • Hall A has “counting” mode (CW)
  • Efficiency studies
  • Tagged photon beam
  • Greater electron detector resolution

So why haven’t we done better before?

Design (4.5GeV)

PREX H-III PV-DIS

11 GeV

Distance from primary beam [mm] Asymmetry

  • Small asymmetries

= long time to precision = cross-checks are difficult

  • Zero-crossing technique is new. (zero

crossing gets hard near the beam)

  • Photon calorimetry is harder at small Eγ

Its a major effort, but there is no

  • bvious fundamental show-

stopper

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SLIDE 27

July 28, 2010 PVDIS 27

Layout ofSpectrometer using CDF coil

  • Coil mounting is well

understood from CDF –Designed to be supported by end –Supports allow radial movement in both ends for thermal –One end fixed axially

  • Will need to check for

decentering forces due to field asymmetry (Lorentz forces)