the q p weak experiment – a search for new physics at the tev scale

M. Pitt, Virginia TechLANL Seminar, 2005

The Qpweak Experiment – A Search for New

Physics at the TeV Scale

Mark Pitt Virginia Tech

• Brief review of recent and planned low energy neutral current Standard Model tests

• Overview and status report of an approved JLAB Standard Model test – The Qp

weak Experiment

• Brief review of most recent results on strange electric and magnetic form factors of the nucleon

M. Pitt, Virginia TechLANL Seminar, 2005What about the running of

sin2W?

Running coupling constants in QED and QCDQED (running of )

s

QCD(running of s)

137


“Running of sin2W” in the Electroweak Standard Model

• Electroweak radiative corrections sin2W varies with Q + +

• All “extracted” values of sin2W must agree with the Standard Model prediction or new physics is indicated.


Why are Precision Measurements far Below the Z-pole Sensitive to New Physics?

Precision measurements well below the Z-pole have more sensitivity(for a given experimental precision) to new types of tree level physics,such as additional heavier Z’ bosons.

'

ZZZZ iMMq

gA

22

2

2'

2

''2

'2

2

'

2'

2

Z

Mq

ZZZZ M

g

iMMq

gA Z

GeV 500 precision 0.1% ~ ,11

~,~ pole,-ZAt '2'

22 Z

ZZZZ M

MMAMq

TeV 2.5 precision 0.1% ~ ,11

~, energy,low At '2'

222 Z

ZZZ M

MMAMq


Low Energy Weak Neutral Current Standard Model Tests

These three types of experiments are a complementary set for exploring newphysics possibilities well below the Z pole.

Low energyweak charge “triad” (M. Ramsey-Musolf)probed in weak neutral current experiments

Z

N e

NZNQ WA

W )sin41( 2

SLAC E158: parity-violating Moller scattering

e + e e + e

Cesium Atomic Parity Violation: primarily sensitive

to neutron weak charge

JLAB Qpweak: parity-violating

e-p elastic scattering

e + p e + p

)sin41( 2W

eWQ

Wp

WQ 2sin41


Qeweak : Electron Weak Charge – SLAC E158 Experiment

Parity-violating Moller scatteringQ2 ~ .026 GeV2 ~ 4 – 7 mrad

E ~ 48 GeV

at SLAC End Station A

e + e e + e

Final results: hep-ex/0504049APV = -131 14 (stat) 10 (syst) ppb

sin2eff(Q2=0.026 GeV2) = 0.2397 ± 0.0010 ±0.0008Running of sin2eff established at 6 level in pure leptonic sector


Atomic Parity Violation in the Cesium Atom

(B x E)

PNC expt. + atomic theory: QW(133Cs) = -72.84 ± (0.29)expt ± (0.36)theor

Standard Model prediction: QW(133Cs) = -73.09 ± (0.03)

after a turbulent 2-year period as the atomic theory was successively improved.

Boulder 133Cs experiment (Wood et al., Science 275, 1759 (1997)): • Measures modification of neutral weak current to the S-P Stark mixing in an applied electric field• Isolate the parity non-conserving piece (PNC) with five different reversals


Future Directions for PV Moller and APVe2ePV: Parity-Violating Moller scattering at 12 GeV JLAB(Mack, Reimer, et al.)

● Paris group (Bouchiat, Paris group (Bouchiat, et al.)et al.): more precise Cs APV: more precise Cs APV

● Seattle group (Fortson, Seattle group (Fortson, et al.)et al.): single trapped Ba: single trapped Ba++ APV 6S APV 6S1/21/2 5D 5D3/23/2

● Berkeley group (Budker, Berkeley group (Budker, et alet al.): isotope ratios in Yb APV.): isotope ratios in Yb APV

● Stony Brook/Maryland group (Orozco, Stony Brook/Maryland group (Orozco, et al.et al.): isotope ratios in Fr APV): isotope ratios in Fr APV

Note: isotope ratios can eliminate large atomic structure theory uncertaintiesNote: isotope ratios can eliminate large atomic structure theory uncertainties

Atomic Parity Violation Future Directions

• Achieve Moller focus with long, narrow superconducting toroidal magnet, Radiation hard detector package• E = 12 GeV Q2 =.008 GeV2 , ~ .53 - .92o , APV = - 40 ppbIn 4000 hours, could determine Qe

W to 2.5%(compare to 12.4% for E158)


Potential of e2ePV: Parity-Violating Moller at 12 GeV JLAB

A 12 GeV Moller experiment could be comparable to the world’s bestweak mixing angle measurements at the Z pole (~ 0.1%).


“Running of sin2W” : Current Status and Future Prospects

present:“d-quark dominated” : Cesium APV (QA

W): SM running verified at ~ 4 level“pure lepton”: SLAC E158 (Qe

W ): SM running verified at ~ 6 level

future:“u-quark dominated” : Qweak (Q

pW): projected to test SM running at ~ 10

level“pure lepton”:12 GeV e2ePV (Qe

W ): projected to test SM running at ~ 25 level


The Qpweak Experiment:

A Search for New TeV Scale Physics via a

Measurement of the Proton’s Weak Charge

Measure: Parity-violating asymmetry in e + p elastic scattering at Q2 ~ 0.03 GeV2

to ~4% relative accuracy at JLab

Extract: Proton’s weak charge Qpweak ~ 1 – 4 sin2W

to get ~0.3% on sin2W at Q2 ~ 0.03 GeV2

tests “running of sin2W” from M2Z to low Q2

sensitive to new TeV scale physics


The QpWeak Experiment JLAB E02-020:

“A Search for new physics beyond the Standard Model at the TeV Scale”

The QpWeak Experiment JLAB E02-020:

“A Search for new physics beyond the Standard Model at the TeV Scale”

The Collaboration

D. Armstrong, T. Averett, J. Birchall, T. Botto, J. D. Bowman, P. Bosted, A. Bruell, R. Carlini (PI), S. Chattopadhay, C. Davis, J. Doornbos, K. Dow, J. Dunne, R. Ent, J. Erler, W. Falk, M. Farkhondeh, J.M. Finn, T. Forest, W. Franklin, D. Gaskell, K. Grimm, F. W. Hersman, M. Holtrop, K. Johnston, R.

Jones,K. Joo, C. Keppel, M. Khol, E. Korkmaz, S. Kowalski, L. Lee, Y. Liang, A. Lung, D. Mack, S. Majewski, J. Martin, J. Mammei, R. Mammei, G. Mitchell, H. Mkrtchyan, N. Morgan, A. Opper, S.A. Page, S.

Penttila,M. Pitt, B. (Matt) Poelker, T. Porcelli, W. Ramsay, M. Ramsey-Musolf, J. Roche, N. Simicevic, G.

Smith (PM), T. Smith, R. Suleiman, S. Taylor, E. Tsentalovich, W.T.H. van Oers, S. Wells, W.S. Wilburn, S. Wood, H. Zhu, C. Zorn, T. Zwart

The Institutions

JLab, LANL, MIT, TRIUMF, William & Mary, Univ. of Manitoba, Virginia Tech, Louisiana Tech, Univ. of Connecticut, Univ. Nacional Autonoma de Mexico, Univ. of Northern British Columbia, Univ. of New Hampshire, Ohio Univ., Mississippi State, Hampton Univ., Yerevan Physics Institute

May 2000 Collaboration formedJuly 2001 JLab Letter of IntentDecember 2001 JLab Proposal SubmittedJanuary 2002 JLab Proposal Approved with ‘A’ ratingJanuary 2003 Technical design review completed,2003 - 2004 Funding approved by to DOE, NSF & NSERCJanuary 2005 JLAB Jeopardy Proposal approved with ‘A’ rating


Jefferson Lab in Newport News, Virginia

CEBAF: CW electron accelerator, energies up

to 6 GeV


80’s: e + 9Be (QE) A ~ 10 ppm Mainz e + 12C (elastic) A ~ 1 ppm MIT-Bates Goal: Standard Model test

90’s, 00’s: SAMPLE HAPPEX e + p (elastic) A ~ 2 – 50 ppm G0 MAMI PV-A4 e + d (QE)Goal: Assume Standard Model is correct, measure strange form factors

70’s: e + d (DIS) A ~ 100 ppm SLAC E122 (Prescott, et al)Goal: measure sin2 θW = 0.22 +/- .0.02most precise measurement at that time

Brief History of Parity Violating Electron-Nucleon Scattering

00’s: Qpweak A ~ 0.3 ppm

Goal: sin2 θW)/sin2 W ~ 0.3% at low Q2

Standard Model test


072.0~sin41Q 2W

pweak (at tree level)

24200Q

22

QQQ24

,QQQ24

2

2

QBG

FG

M

MA

pweak

F

ppweak

F

EM

NC

ZMEME GG ,, and contains

Qpweak: Extract from Parity-Violating Electron Scattering

measures Qp – proton’s electric charge measures Qpweak

– proton’s weak charge

MEM MNC

As Q2 0

• Qpweak is a well-defined experimental observable

• Qpweak has a definite prediction in the electroweak Standard Model


eh

)scattering (elastic Ne

LR

LRA

2

e e pp

652

F 1010factorsform4

G-

Q

How to Measure the Neutral weak form factors


Le-q

PV LSMPV LNEW

PV GF

2e e C1qq q

q

g2

4 e e hVqq q

q

• Parameterize New Physics contributions in electron-quark Lagrangian

• A 4% QpWeak measurement probes with

95% confidence level for new physics at energy scales to:

g: coupling constant, : mass scale

g

2 GF QWp 2.3 TeV

QpWeak projected 4% (2200 hours production)

QpWeak projected 8% (14 days production)

SLAC E158, Cs APV

FermiLab Run I I projectedFermiLab Run I

4

3

2

1

00 2 4 6 8 10 12

QpWeak/ Qp

Weak (%)

Mass Sensitivity vs QpWeak/ Qp

Weak

68% CL

95% CL

• The TeV discovery potential of weak charge measurements will be unmatched until LHC turns on.

• If LHC uncovers new physics, then precision low Q2 measurements will be needed to determine charges, coupling constants, etc.

Energy Scale of an “Indirect” Search for New Physics


Impact of QpWeak “Model-independent Semi-Leptonic Analysis”

Effective electron-quark neutralcurrent Lagrangian:

Large ellipse (existing data):SLAC e-D (DIS)MIT-Bates 12C (elastic)Cesium APVRed ellipse:Impact of Qp

Weak measurement(centroid assumes agreementwith standard model)

Why so much better?• precision & complementarity of Qp

W measurement

C1u C1u(exp) C1u(SM)C1d C1d(exp) C1d(SM)

Le-qPV

GF

2e e C1qq q

q

A(e) x V(q)


JLab QweakJLab Qweak

Run I + II + III (preliminary) ±0.006

(proposed)-

• Qweak measurement will provide a stringent stand alone constraint on Lepto-quark based extensions to the SM.

• Qpweak (semi-leptonic) and E158 (pure leptonic) together make a

powerful program to search for and identify new physics.

SLAC E158SLAC E158

Qpweak & Qe

weak – Complementary Diagnostics for New Physics

Erler, Kurylov, Ramsey-Musolf, PRD 68, 016006 (2003)


R parity (B-L conservation)

RPC SUSY occurs onlyat loop level

RPV SUSY occurs attree level

Relative Shifts in Proton and Electron Weak Chargesdue to SUSY Effects

Z 0

˜

˜ e

e p

p

Erler, Ramsey-Musolf, Su hep-ph/0303026


Overview of the QpWeak Experiment

Incident beam energy: 1.165 GeVBeam Current: 180 μABeam Polarization: 85%LH2 target power: 2.5 KW

Central scattering angle: 8.4° ± 3°Phi Acceptance: 53% of 2Average Q²: 0.030 GeV2

Acceptance averaged asymmetry: –0.29 ppmIntegrated Rate (all sectors): 6.4 GHz Integrated Rate (per detector): 800 MHz

Experiment Parameters(integration mode)

35 cm Liquid Hydrogen Target

Polarized Electron Beam

Collimator With Eight Openings = 9 ± 2°

Toroidal Magnet

Eight Fused Silica (quartz)Cerenkov Detectors

5 inch PMT in Low GainIntegrating Mode on Each

End of Quartz Bar

Elastically Scattered Electrons

325 cm

580 cm

LuninosityMonitor

Region 3Drift Chambers

Region 2Drift Chambers

Region 1GEM Detectors

Polarized Electron Beam

35cm Liquid Hydrogen Target

Collimator with 8 openingsθ= 8° ± 2°

Region IGEM Detectors

Region IIDrift Chambers

Toroidal Magnet

Region IIIDrift Chambers

Elastically Scattered Electron

Eight Fused Silica (quartz)Čerenkov Detectors

Luminosity Monitors


Aphys /Aphys Qp

weak/Qpweak

Statistical (2200 hours production) 1.8% 2.9%Systematic:

Hadronic structure uncertainties -- 1.9% Beam polarimetry 1.0% 1.6% Absolute Q2 determination 0.5% 1.1% Backgrounds 0.5% 0.8% Helicity-correlated Beam Properties 0.5% 0.8%_________________________________________________________ Total 2.2% 4.1%

Aphys /Aphys Qpweak/Qp

weak

Statistical (2200 hours production) 1.8% 2.9%Systematic:

Hadronic structure uncertainties -- 1.9% Beam polarimetry 1.0% 1.6% Absolute Q2 determination 0.5% 1.1% Backgrounds 0.5% 0.8% Helicity-correlated Beam Properties 0.5% 0.8%_________________________________________________________ Total 2.2% 4.1%

(Erler, Kurylov, Ramsey-Musolf, PRD 68, 016006 (2003))Qp

W = 0.0716 0.0006 theoretically0.8% error comes from QCD uncertainties in box graphs, etc.

(Erler, Kurylov, Ramsey-Musolf, PRD 68, 016006 (2003))Qp

W = 0.0716 0.0006 theoretically0.8% error comes from QCD uncertainties in box graphs, etc.

Anticipated QpWeak Uncertainties

4% error on QpW corresponds to ~0.3% precision on sin2W at Q2 ~ 0.03 GeV2


Constraints on Ahadronic from other Measurements

Quadrature sum of expected Ahadronic = 1.5% and Aaxial = 1.2% errors

contribute ~1.9% to error on QpW

A AQW

p Ahadronic Aaxial

.19 ppm .09 ppm .01 ppm

A AQW

p Ahadronic Aaxial

.19 ppm .09 ppm .01 ppm

hadronic: (31% of asymmetry) - contains G

E,M GZE,M

Constrained by HAPPEX, G0, MAMI PVA4

hadronic: (31% of asymmetry) - contains G

E,M GZE,M

Constrained by HAPPEX, G0, MAMI PVA4

axial: (4% of asymmetry) -

contains GeA,

has large electroweak radiative corrections.

Constrained by G0 and SAMPLE

axial: (4% of asymmetry) -

contains GeA,

has large electroweak radiative corrections.

Constrained by G0 and SAMPLE

Nucleon Structure Contributions to the Asymmetry

)( 24 QBQAhadronic


What role do strange quarks play in nucleon properties?u

ud

u

us

s

valence quarks

“non-strange” sea (u, u, d, d) quarks

“strange” sea (s, s) quarks

Momentum:

Spin:

Mass:

Charge and current:

There has been a decade long effort to measure the vector strange form factors.

(DIS) %4 ~ )(1

0

dxssx

proton

gluon

DIS) (polarized %10 ~ | | NssN

term)-( %30 ~ || NNssN

?? | | sM

sE GGNssN


Strange Vector Form Factors – GEs and GM

s

The strange vector form factors measure the contribution of the strange quark sea to the electromagnetic properties of the nucleon.

)( 2QG sE

nsME

ndME

nuME

nME

psME

pdME

puME

pME

GGGG

GGGG

,,

,,

,,

,,

,,

,,

,,

,,

3

1

3

1

3

23

1

3

1

3

2

)( 2QG sM

Strange electric form factor: measures the contribution of thestrange quark sea to the nucleon’s spatial charge distribution.Strange magnetic form factor: measures the contribution of thestrange quark sea to the nucleon’s spatial magnetization distribution.


Parity Violating Electron Scattering - Probe of Neutral Weak Form Factors

polarized electrons, unpolarized target

unpol

AMEF

LR

LR AAAQGA

224

2

2

e e pp

)()()sin41()()()(

)()()(

222

222

22

QGQGAQGQGQA

QGQGA

MeAWA

MZMM

EZEE

eA

sM

sE

GGG

At a given Q2 decomposition of GsE, Gs

M, GeA

Requires 3 measurements:

Forward angle e + p (elastic)Backward angle e + p (elastic)Backward angle e + d (quasi-elastic)

Strange electric and magnetic

form factors,+ axial form factor


Results of Strange Form Factor Measurements - 2005

Measurements at Q2 = 0.1 GeV2 • MIT-Bates (SAMPLE)• JLAB (HAPPEx)• Mainz (A4)

from G0 and Happex at JLAB

31.062.0)GeV 1.0(

028.0013.0)GeV 1.0(

:)1(at givedata worldCombined

22

22

QG

QGsM

sE


Strange Form Factor Measurements - speculationThe current strange form factor data indicates non-zero values at the~ 2 σ level. If the true values are anywhere near the central values, these are not small effects; ie. experiment has not yet ruled out potentially large strange quark sea contributions to the nucleon’s electromagnetic properties.

factor form magnetic sproton' the tooncontributi 5%10a

implies 31.062.0)GeV 1.0( :exampleFor 22

QG s

M

Results of global fits to all data (need to multiply by -1/3 to get contribution)

More data coming in 2005-2006 from JLAB and Mainz

from D. Beck

M. Pitt, Virginia Tech PAVI 2002, Mainz

Region 3: Vertical Drift chambers

Region 2: Horizontal drift chamber locationRegion 1: GEM

Gas Electron Multiplier

Quartz Cherenkov Bars(insensitive to non-relativistic particles)

Collimator System

Mini-torus

QTOR Magnet

Trigger Scintillator

Lumi Monitors

e- beam

The Qweak Apparatus (Calibration Mode Only - Production & Calibration Modes)

Ebeam = 1.165 GeVIbeam = 180 μAPolarization ~85%Target = 2.5 KW


•8 toroidal coils, 4.5m long along beam•Resistive, similar to BLAST magnet • Pb shielding between coils• Coil holders & frame all Al

• Bdl ~ 0.7 T-m• bends elastic electrons ~ 10o

• current ~ 9500 AStatus: coils being wound in France support stand designed, out for bid

QpWeak Toroidal Magnet - QTOR


View Along Beamline of QpWeak Apparatus - Simulated EventsView Along Beamline of QpWeak Apparatus - Simulated Events

Central scattering angle: ~8° ± 2Phi Acceptance: > 50% of 2Average Q²: 0.030 GeV2

Acceptance averaged asymmetry: –0.29 ppmIntegrated Rate (per detector): ~801 MHzInelastic/Elastic ratio: ~0.026%

Central scattering angle: ~8° ± 2Phi Acceptance: > 50% of 2Average Q²: 0.030 GeV2

Acceptance averaged asymmetry: –0.29 ppmIntegrated Rate (per detector): ~801 MHzInelastic/Elastic ratio: ~0.026%

Very clean elastic separation!

rectangular quartz bar;18 cm wideX 2 meterslong

rectangular quartz bar;18 cm wideX 2 meterslong

Inelastic/Elastic Separation in QpWeak


Focal plane detector requirements:

• Insensitivity to background , n, .• Radiation hardness (expect > 300 kRad).• Operation at counting statistics.

Fused Silica (synthetic quartz) Cerenkov detector.

• Plan to use 18 cm x 200 cm x 1.25 cm quartz • bars read out at both ends by 5 inch S20 • photocathode PMTs (expect ~ 100 pe/event)• n =1.47, Cerenkov=47°, total internal reflection tir=43°• reflectivity = 0.997

Electronics (LANL/TRIUMF design):

• Normally operates in integration mode.• Will have connection for pulse mode.• Low electronic noise contribution.

compared to counting statistics.• 18 bit ADC will allow for 4X over sampling.

The QpWeak Detector and Electronics System


Target Concept:

• Similar in design to SAMPLE and G0 targets longitudinal liquid flow high stream velocity achieved with perforated, tapered “windsock”

Target Concept:

• Similar in design to SAMPLE and G0 targets longitudinal liquid flow high stream velocity achieved with perforated, tapered “windsock”

QpWeak Target parameters/requirements:

• Length = 35 cm• Beam current = 180 A • Power = 2200 W beam + 300 W heater• Raster size ~4 mm x ~4 mm square• Flow velocity > 700 cm/s• Density fluctuations (at 15 Hz) < 5x10-5

QpWeak Target parameters/requirements:

• Length = 35 cm• Beam current = 180 A • Power = 2200 W beam + 300 W heater• Raster size ~4 mm x ~4 mm square• Flow velocity > 700 cm/s• Density fluctuations (at 15 Hz) < 5x10-5

The QpWeak Liquid Hydrogen Target


• Construct target that does not “boil" at a level << 50ppm/pulse pair level (assuming a 30Hz helicity reversal). Options: large raster size, faster pump speed, better cooled windows....

• Use Luminosity monitors to normalize experiment instead of beam current.

• Assume “boiling” is not a resonant phenomena and “noise” is the result of small “bubbles” formed along the target length being ejected from the beam region.

Decrease relative contributionof “boiling” by increasingthe reversal/data readoutrate.

noise/pulse pair decreases as the reversal/readout frequency is raised.

• Target starts to appear as “solid” w.r.t. any single asymmetry calculation.

Vertical scale is proportional to noise/ (Hz1/ 2)

Black curve is Hall A LD2 data.

Red data are carbon and indicates that there was negligible electronic rollof f .

Magnitude of the red line is probably the noise f loor of non-parity qualityADC’s in use at the time.

(0.1 Hz)0 50 100 150 200

Frequency (Hz)

Limiting the Target “boiling noise” Contribution2

2

t

tcountingrandom


photocathode

NF3

Laser

Cs

anode

e -

-100 kV

HV insulator

NEG pumps

Strained GaAs in Gun2 (“old” material) ~ 75% Polarized

Strained-superlattice GaAs In Gun3 (“new” material) ~ 85% Polarized

NEG-coated Beamline

The polarized electrons are generated by photoemissionfrom a GaAs semiconductorwith polarized laser light

Polarized Electron Guns at JLabPolarized Electron Guns at JLab


N

iiP

YYphysmeas PAA

i1

21

P = P+ – P-

Y = Detector yield

(P = beam parameter ~energy, position, angle, intensity)

nm100 , mm/%0.1~21

xxY

Y

ppm110~ 621

false xA xY

Y

Example:

ppm1II

IIA

-

-I

Typical goals for run-averaged beam properties

nm 20 - 2 y x, Intensity: Position:

PPP

P2

1Y

Y

keep small with feedback and careful setup

keep small with symmetrical detector setup

Helicity Correlated Beam Properties: False Asymmetry Corrections


• Luminosity monitor Symmetric array of 8 quartz Cerenkov detectors instrumented with rad hard PMTs operated in “vacuum

photodiode mode” & integrating readout at small (~ 0.8).

Low Q2, high rates ~29 GHz/octant.

• Expected signal components: 12 GHz e-e Moeller, 11 GHz e-p elastic, EM showers 6 GHz. • Expected lumi monitor asymmetry << main detector asymmetry.• Expected lumi monitor statistical error ~ (1/6) main detector statistical error.

• Useful for:

Sensitive check on helicity-correlated beam parameter corrections procedure.

Regress out target density fluctuations.

The QpWeak Luminosity Monitor


Region 3: Vertical

Drift chambers

Region 2: Horizontal drift chamber location

Region 1: GEMGas Electron

Multiplier

Quartz Cherenkov Bars(insensitive to non-relativistic particles)

Trigger Scintillator

e- beam

Expected Q2 distribution

Region 1 + 2 chambers --> determine value of Q2

Region 3 chamber --> efficiency map of quartz detectors

Q2 Determination

Use low beam current (~ few nA) to run in “pulse counting” mode with a trackingsystem to determine the “light-weighted” Q2 distribution.


Hall C has existing ~1% precision Moller polarimeter

• Present limitations:- IMax ~ 10 A.

- At higher currents the Fe target

depolarizes.- Measurement is destructive

• Plan to upgrading Møller:- Measure Pbeam at 100 A or

higher, quasi-continuously- Trick: kicker + strip or wire

target (early tests look promising – tested up to 40 A so far)

• Schematic of planned new Hall C Compton polarimeter.

Q2

D2

Q1

D3

D1D=0.52 m

1 m2 m 1.5 m

9.5 m

Electron detector

D4

PhotonDetector

Precision Polarimetry


• Completed low energy Standard Model tests are consistent with Standard Model “running of sin2W”

SLAC E158 (running verified at ~ 6 level) - leptonicCs APV (running verified at ~ 4 level ) – semi-leptonic, “d-quark

dominated”

• Upcoming QpW Experiment

• Precision measurement of the proton’s weak charge in the simplest system.• Sensitive search for new physics with CL of 95% at the ~ 2.3 TeV scale.• Fundamental 10 measurement of the running of sin2W at low energy.• Currently in process of 3 year construction cycle; goal is to have multiple runs in 2008 – 2009 timeframe

• Possible 12 GeV Parity-Violating Moller Experiment at JLAB

• Conceptual design indicates reduction of E158 error by ~5 may be possible at 12 GeV JLAB.

weak charge triad (Ramsey-Musolf)

Summary

the q p weak experiment – a search for new physics at the tev scale

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