1. Exploring the Standard Model with JLab at 12 GeV
17 January 2003
Standard Model tests: Beyond sin2(qW).
e2ePV: Moller Scattering at 11 GeV
DIS-Parity: Parity NonConserving Electron Deep Inelastic Scattering
For Dave Mack, Paul Souder, Michael Ramsey-Musolf, et al.

2. sin2(qW) measurements below Z-pole
Standard Model predicts sin2(qW) varies (runs) with Q2
Non-S.M. physics may move measurements away from running curve.
Different measurements sensitive to different non-S.M. physics.
Well measured at Z-pole, but not at other Q2.
NuTeV nA scattering:
3s from Standard Model!!!
Fe target: PDF’s in iron? Nuclear corrections?
Atomic Parity Violation (APV):
Hard to understand theoretically.
Consistent with S.M. (plot is out of date)
Future measurements
Qweak (Jlab)
Qweak PROTON ¼
E158-Moller
QWeak ELECTRON
Final run 2003
e2ePV
11 GeV-Moller Scattering
Q2 = GeV2.
DIS-Parity
11 GeV JLab DIS Parity Violation
Q2 = 3.5 GeV2
17 January 2003
Paul E. Reimer, Argonne National Laboratory

3. Beyond sin2(qW): e.g. SUSY and Dark Matter
NASA Hubble NGC3310
What is Dark Matter?
S.M.: QWelectron and QWproton both measure 1-4sin2(qW).
SUSY: Loop contributions can change this by measurable amounts!
hep-ph/
RPV
No SUSY dark matter
JLab QWeak (proton) and SLAC E158 Moller (QWe) anticipated limits.
17 January 2003
Paul E. Reimer, Argonne National Laboratory

4. e2ePV: Parity Violating Moller Scattering at 12 GeV
D. Mack, W. van Oers, R. Carlini, N. Simicevic, G. Smith
17 January 2003
Paul E. Reimer, Argonne National Laboratory

5. e2ePV: Moller Scattering at 12 GeV
Measurement of QWeak of the electron.
Very small asymmetry:
A|11 GeV ¼ 9¢10-7 (1 – 4 sin2qW) ¼ 4¢10-8.
Near-vanishing of the tree-level asymmetry makes this measurement sensitive to
New physics at tree-level (e.g. Z0),
New physics via loops (e.g. SUSY loop contributions).
Restriction the available parameter space by a small amount is useful!
Is there room for JLab to improve on the SLAC E158 measurement? What type of apparatus would be needed?
17 January 2003
Paul E. Reimer, Argonne National Laboratory

6. Moller sin2 qW Error De-Magnification
Radiative corrections
Not all of which are suppressed (De-Magnified) by (1-4sin2(qW)
Reduce tree-level Moller asymmetry by ¼ 40%
17 January 2003
Paul E. Reimer, Argonne National Laboratory

7. Paul E. Reimer, Argonne National Laboratory
Moller 12 GeV vs. 48 GeV
Repeat SLAC-E158 Moller
Figure of merit:
A2 ds/dW / Ebeam.
Factor of 4 better at SLAC.
All else equal, the advantage goes to the higher beam energy—but “all else” is not equal!!
JLab can have a clear advantage in luminosity.
17 January 2003
Paul E. Reimer, Argonne National Laboratory

8. JLab 12 GeV Moller vs. SLAC E158
JLab’s advantage comes from the higher integrated luminosity available.
17 January 2003
Paul E. Reimer, Argonne National Laboratory

9. Moller sin2(qW) Anticipated Uncertainties
Clearly a competitive measurement of sin2qW is possible at 11 GeV which is competitive with the best single measurements below and at the Z-pole.
17 January 2003
Paul E. Reimer, Argonne National Laboratory

10. Moller Detection Laboratory scattering angles are small!!
Detector Requirements:
Focus Moller electrons of momentum 4.5 GeV/c § 33%.
Toroidal magnet with 1/R field is well suited.
Field requirement are less and scattering angle larger than at SLAC
Detector Concept:
Drift scattered electrons to a collimator.
Focus electrons in a resistive toroidal magnet.
Drift electrons to detector ring.
17 January 2003
Paul E. Reimer, Argonne National Laboratory

11. e2ePV Moller Conclusions
There is a small window for a Moller exp. at JLab to improve over SLAC E-158.
This improvement can have a significant impact on the range of allowable SUSY extensions.
RPV
No SUSY dark matter
hep-ph/
JLab QWeak (proton) and JLab e2ePV Moller (QWe) anticipated limits.
17 January 2003
Paul E. Reimer, Argonne National Laboratory

12. Paul E. Reimer, Argonne National Laboratory
DIS-Parity: Polarized e- deuterium Deep Inelastic Scattering Parity NonConservation
Paul Reimer, Peter Bosted, Dave Mack
17 January 2003
Paul E. Reimer, Argonne National Laboratory

13. Textbook Physics: Polarized e- d scattering
Repeat SLAC experiment (30 years later) with better statistics and systematics at 12 GeV Jefferson Lab:
Beam current 100 mA vs. 4 mA at SLAC in ’78 £ 25 stat
60 cm target vs. 30 cm target £ 2 stat
Pe (=electron polarization) = 80% vs. 37% £ 4 stat
d Pe ¼ 1% vs. 6% £ 6 sys
17 January 2003
Paul E. Reimer, Argonne National Laboratory

14. DIS-Parity: Polarized e- deuterium DIS
Longitudinally polarized electrons on unpolarized isoscaler (deuterium) target.
C1q ) NC vector coupling to q
£ NC axial coupling to e
C2q ) NC axial coupling to q
£ NC vector coupling to e
Note that each of the Cia are sensitive to different possible S.M. extensions.
17 January 2003
Paul E. Reimer, Argonne National Laboratory

15. DIS-Parity: Detector and Expected Rates
Expt. Assumptions:
60 cm ld2/lH2 target
11 GeV 90mA
75% polar.
12.5± central angle
12 msr dW
6.8 GeV§10% mom. bite
Rate expectations:
¼ 1MHz DIS
p/e ¼ 1 ) 1 MHz pions
2 MHz Total rate
dA/A = 0.5% ) 2 weeks (ideal) plus time for H2 and systematics studies.
Will work in either Hall C (HMS +SHMS) or Hall A (MAD)
hxi = hQ2i = 3.5 GeV2
hYi = 0.46 hW2i = 5.23 GeV2
Q2 near NuTeV result—provide cross check on neutrino result.
17 January 2003
Paul E. Reimer, Argonne National Laboratory

16. Paul E. Reimer, Argonne National Laboratory
Uncertainties in Ad
Beam Polarization:
This drives the uncertainty!
QWeak also needs 1.4%
Hall C Moller claims 0.5%.
Higher twists may enter at low Q2:
This could be a problem.
Check by taking additional data at lower and higher Q2.
Possible 6 GeV experiment?
Ad to § 0.5% stat § 1.1% syst. (1.24% combined)
Statistical (2 weeks)
0.5%
Beam polarization
1.0%
dQ2
Radiative corr.
<1%
dR = d(sL/sT) = § 15%
<0.02%
ds(x) = § 10%
<0.03%
EMC Effect
????
Higher Twist
What about Ciq’s?
17 January 2003
Paul E. Reimer, Argonne National Laboratory

17. Extracted Signal—It’s all in the binning
PDG: C1u= –0.209§0.041 highly
C1d= §0.037 correlated
2C2u– C2d = –0.08§0.24
This measurement:
d(2C1u– C1d) = (stat.)
d(2C2u– C2d) = (stat.)
Note—Polarization uncertainty enters as in slope and intercept
Aobs = PAd / P(2C1u–C1d) + P(2C2u–C2d)Y]
but is correlated
17 January 2003
Paul E. Reimer, Argonne National Laboratory

18. DIS-Parity determines 2C2u-C2d
Combined result significantly constrains 2C2u–C2d.
PDG 2C2u–C2d = –0.08 § Combined d(2C2u–C2d) = § 0.014
£ 17 improvement (S.M 2C2u – C2d = )
17 January 2003
Paul E. Reimer, Argonne National Laboratory

19. DIS-Parity: Conclusions
DIS-Parity Violation measurements can easily accomplished at JLab with the 12 GeV upgrade (beam and detectors) in either Hall A or Hall C.
Large asymmetry/quick experiment.
Requires very little beyond the standard equipment which will already be present in the halls.
Near NuTeV Q2.
Higher twist may be important
d(2C1u – C1d) = 0.005
d(2C2u – C2d) = 0.014
17 January 2003
Paul E. Reimer, Argonne National Laboratory

20. JLab tests of the Standard Model
Measurements of sin2(qW) below MZ provide strict tests of the SM.
Measurements in different systems provide complementary information.
Moller Parity Violation can be measured at JLab at a level which will impact the Standard Model.
DIS-Parity violation measurement is easily carried out at JLab.
hep-ph/
RPV
Weak Mixing Angle MS-bar scheme
Jens Erler
No SUSY dark matter
17 January 2003
Paul E. Reimer, Argonne National Laboratory