hall c meeting january 2008 juliette m. mammei virginia tech for the qweak collaboration funded by...

Hall C MeetingJanuary 2008

Juliette M. MammeiVirginia Tech

for the Qweak Collaboration

Funded by NSF, DOE, SURA, NSFGRF, VT Cunningham

Qweak: A Search for New Physicsat the TeV Scale

D. Armstrong, T. Averett, J. Benesch, J. Birchall, P. Bosted, A. Bruell, C. Capuano, R. Carlini1 (Contact Person), G. Cates, S. Chattopadhyay, S. Covrig, CA Davis,

K. Dow, J. Dunne, D. Dutta, R. Ent, J. Erler, W. Falk, JM Finn1, T. Forest, W. Franklin, D. Gaskell, J. Grames, M. Gericke, K. Grimm, FW Hersman, M. Holtrop, P. King,

K. Johnston, R. Jones, K. Joo, C. Keppel, M. Khol, E. Korkmaz, S. Kowalski1, L. Lee, Y. Liang, A. Lung, D. Mack, S. Majewski, J. Mammei, R. Mammei, J. Martin, D. Meekins, H.

Mkrtchyan, N. Morgan, K. Myers, A. Opper, SA Page1, J. Pan, K. Paschke, M. Pitt, B. (Matt) Poelker, T. Porcelli, Y. Prok, WD Ramsay, M. Ramsey-Musolf, J. Roche, N. Simicevic, G. Smith2, R. Suleiman, E. Tsentalovich, WTH van Oers, P. Wang,

S. Wells, S. Wood, R. Young, H. Zhu, C. Zorn

1Co-pokespersons2Project Manager

California Institute of Technology, College of William and Mary, George Washington University, Hampton University, Idaho State University, Louisiana Tech University, Massachusetts Institute of Technology, Mississippi State University, Ohio University, Thomas Jefferson National Accelerator

Facility, TRIUMF, University of Connecticut, University of Manitoba, University of Mexico, University of New Hampshire, University of Northern British Columbia, University of Virginia, University of

Winnipeg, Virginia Polytechnic Institute & State University, Yerevan Physics Institute

The Qweak Collaboration


2Q 0

20 2 4Q Q

2

4 2Q

N

pwe

C

EM

Fak

Md dA

d d M

GB Q

Weak Charges of Light Quarks

3/2sin3

41 2 W

3/1sin3

81 2 W

0713.sin41 2 W

1

upq

downq

downupp qqQ 12

downupn qqQ 21

3/2

3/1

1

0

EM Charge Weak Charge EM Charge

Weak Charge


“Running” of sin2W

• Electroweak radiative corrections sin2W varies with Q + +

The “running” curve is normalized by measurements at the Z0 resonance.

Standard Model PredictionErler, Kurylov & Ramsey-Musolf,Phys. Rev. D 68, 016006 (2003)


Hadronic Structure Contribution

22 )( QQBQA pweak

pLR

PDG

SMtheoretical estimates of anapole form factor

Qpweak

Young, Ross, et. al. PRL 99:122003,2007


Sensitivity to TeV Scale

Erler et al., PRD68(2003)

Data sets limits on TeVQGg p

weakF

3.2222

1


Neutral Weak Effective Couplings

Young, Ross, et. al. PRL 99:122003,2007


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

Limits on Extensions to the Standard Model

Z 0

˜

˜ e

e p

p


Aphys /Aphys Qpweak/Qp

weak

Statistical (2200 hours production) 2.1% 3.2%

Systematic: Hadronic structure uncertainties -- 1.5% Beam polarimetry 1.0% 1.5% Absolute Q2 determination 0.5% 1.0% Backgrounds 0.5% 0.7% Helicity-correlated Beam Properties 0.5% 0.7%_________________________________________________________ Total 2.5% 4.1%

Aphys /Aphys Qpweak/Qp

weak

Statistical (2200 hours production) 2.1% 3.2%

Systematic: Hadronic structure uncertainties -- 1.5% Beam polarimetry 1.0% 1.5% Absolute Q2 determination 0.5% 1.0% Backgrounds 0.5% 0.7% Helicity-correlated Beam Properties 0.5% 0.7%_________________________________________________________ Total 2.5% 4.1%

Anticipated QpWeak Uncertainties

Experimental sensitivity: 0713.0)sin41( 2 Wp

WQ

Expected value: A(Q2=0.026 GeV2) = -0.234 ppm !!!

Precision measurement:

%3.0)(sin%4 2 Wp

WQ


Qweak 101 Keep technology simple!

Build on JLab expertise with parity quality polarized beams (1.165

GeV)

Dual Moller and Compton polarimeters (85% polarized beam)

Resistive toroid magnet (particle separation - ~9000A)

Quartz cerenkov detectors in current mode:Rad hard (stable) and rejection of non-relativistic eventsLow gain PMTs operated in linear current integrating modePrecision 18-bit ADC rapid sampling (equivalent to 26 bit)

Counting mode (sub nA beam current) for Q2 calibration

World’s highest power LH2 cryogenic target (~2.5 kW)

Rapid flipping (125 Hz) of beam helicity (up to 500Hz) to suppress

beam systematics and target boiling noise


Target (Design)

QTOR +Power Supply (Mapping soon - Bates)

R-3 Rotation System

(Fabrication)

R-2 HDCs(Fabrication and testing)

DownstreamPb Shielding (Complete)

Beam

Experiment Component Status

GEMs(Prototype + parts)

R-3 VDC(Fabrication)

Main Detectors(Components at JLab)

Lumis(Design)

Collimators(Procurement)

New Quartz Scanner (Design)

Lumis(Design)


Very clean elastic separation!

Main DetectorsView Along Beamline of QWeak Apparatus - Simulated Events

Central scattering angle: ~8° ± 2°Phi Acceptance: ~50% of 2πAverage Q²: 0.026 GeV2

Acceptance averaged asymmetry: –0.234 ppmIntegrated Rate (per detector): ~810 MHzInelastic/Elastic ratio: ~0.4%

Central scattering angle: ~8° ± 2°Phi Acceptance: ~50% of 2πAverage Q²: 0.026 GeV2

Acceptance averaged asymmetry: –0.234 ppmIntegrated Rate (per detector): ~810 MHzInelastic/Elastic ratio: ~0.4%

8 fused silica radiators(Spectrosil 2000)

200cm x 18cm x 1.25cm

5” PMTs (gain = 2000)


Main Detectors

Gluing jig

Quartz bar quality control

PMT gain vs. voltage

Bars, light guides,PMTs, IV preampsdelivered.

Final testing of 18-bitADC prototypes


Target

Beam

Assembling the heat exchanger

Target statusShakedown – with cold He gas Summer ‘08Neon test – early 2009High power test – Spring 2009


MagnetAttaching a coil to the supports

Assembled toroid with mapper

9500 A power supply delivered;Field mapping to begin in March


Tracking system

GEM prototype and rotator

(LA Tech, Idaho State)

Region II HDC (VPI)

Region III VDCand rotator

(W&M)


Conclusion

DOE spending ¾ finished!

most systems are constructing and/or testing

on track to be ready in January ’09

scheduled for Sept. or Nov. ’09

~6 months install, ~4 months commissioning, ~12 months running


Extra Slides


Experiment Status


“DAQ”

Tracking System

Region IGEMs

Region IIHDCs

Region IIIVDCs

QTOR

GEMs – Gas Electron Multiplier HDCs – Horizontal Drift ChamberQTOR – Toroidal Magnet VDCs – Vertical Drift Chamber

TriggerScintillator

If the track doesn’t point to the target, or if the kinematics don’t match an elastic event, then it is background


GEM 1

GEM 2

GEM 3

~12mm

Readout PCBCollection

cathode

amplifier

electron

avalanche

HDCs – Horizontal Drift ChamberVDCs – Vertical Drift ChamberGEMs – Gas Electron Multiplier

GEM 1

GEM 2

GEM 3

~12mm

Readout PCBCollection

cathode

amplifier

electron

avalanchesense wire

guard wire

sense wireguard wire

TRIUMF Custom Low Noise Electronics

VME integrator – 18 bit ADC sampling at 500 kHz

FPGA sums 500 samples into one data word same resolution as a 26 bit ADC

Noise test on bench at TRIUMF

Electronic noise is about 3 orders of magnitude below the counting statistics of electron tracks.

This permits very sensitive checks with LED light sources and battery powered current sources in only one shift.

2 ppb!


Indirect search for new physics

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

JLAB Qweak SLAC E158

• Qpweak (semi-leptonic) and E158 (pure leptonic)

together make a powerful program to search for and identify new physics.


MEMMNC

Interference gives rise toparity violating asymmetry

ep

( )s

ep

( )s

2Q 0

20 2 4Q Q

2

4 2Q

N

pwe

C

EM

Fak

Md dA

d d M

GB Q

Qpweak: Parity-Violating Electron Scattering

Scatter longitudinally polarized electrons on unpolarized protons

072.0)sin41( 2 WpweakQ


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

• 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


In the case of a significant deviation from SM...Constraint including Qweak at central value of current

measurements

Analysis by Ross Young, JLab

atomic onlywith PVES

with Qweak

If LHC finds a Z′, Qweak will help determine its properties


s

137

Q2, GeV2

QED (running of )QCD(running of s)

Running coupling constants in QED and QCD


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


R parity (B-L conservation)

RPC SUSY occurs onlyat loop level

RPV SUSY occurs attree level

Relative Shifts in Proton and Electron Weak Charges due to SUSY Effects

Z 0

˜

˜ e

e p

p

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

hall c meeting january 2008 juliette m. mammei virginia tech for the qweak collaboration funded by...

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