juliette m. mammei virginia tech for the qweak collaboration funded by nsf, doe, sura,
DESCRIPTION
Qweak: A Search for New Physics at the TeV Scale. Juliette M. Mammei Virginia Tech for the Qweak Collaboration Funded by NSF, DOE, SURA, NSFGRF, VT Cunningham. The Qweak Collaboration. D. Armstrong, T. Averett, J. Benesch, J. Birchall, P. Bosted, A. Bruell, C. Capuano, - PowerPoint PPT PresentationTRANSCRIPT
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
Hall C MeetingJanuary 2008
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
Hall C MeetingJanuary 2008
“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)
Hall C MeetingJanuary 2008
Hadronic Structure Contribution
22 )( QQBQA pweak
pLR
PDG
SMtheoretical estimates of anapole form factor
Qpweak
Young, Ross, et. al. PRL 99:122003,2007
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Sensitivity to TeV Scale
Erler et al., PRD68(2003)
Data sets limits on TeVQGg p
weakF
3.2222
1
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Neutral Weak Effective Couplings
Young, Ross, et. al. PRL 99:122003,2007
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Erler, Kurylov, Ramsey-Musolf, PRD 68, 016006 (2003)
Limits on Extensions to the Standard Model
Z 0
˜
˜ e
e p
p
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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
Hall C MeetingJanuary 2008
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
Hall C MeetingJanuary 2008
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)
Hall C MeetingJanuary 2008
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)
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Main Detectors
Gluing jig
Quartz bar quality control
PMT gain vs. voltage
Bars, light guides,PMTs, IV preampsdelivered.
Final testing of 18-bitADC prototypes
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Target
Beam
Assembling the heat exchanger
Target statusShakedown – with cold He gas Summer ‘08Neon test – early 2009High power test – Spring 2009
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MagnetAttaching a coil to the supports
Assembled toroid with mapper
9500 A power supply delivered;Field mapping to begin in March
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Tracking system
GEM prototype and rotator
(LA Tech, Idaho State)
Region II HDC (VPI)
Region III VDCand rotator
(W&M)
Hall C MeetingJanuary 2008
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
Hall C MeetingJanuary 2008
Extra Slides
Hall C MeetingJanuary 2008
Experiment Status
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“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
Hall C MeetingJanuary 2008
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!
Hall C MeetingJanuary 2008
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.
Hall C MeetingJanuary 2008
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
Hall C MeetingJanuary 2008
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
Hall C MeetingJanuary 2008
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
Hall C MeetingJanuary 2008
s
137
Q2, GeV2
QED (running of )QCD(running of s)
Running coupling constants in QED and QCD
Hall C MeetingJanuary 2008
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
Hall C MeetingJanuary 2008
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