# Presentation: 488247

## Exploring the Standard Model with JLab at 12 GeV

- Standard Model tests:  Beyond sin2(***W***).
***e2ePV***:  Moller Scattering at 11 GeV
***DIS-Parity***:  Parity NonConserving Electron Deep Inelastic Scattering

- For Dave Mack, Paul Souder, Michael Ramsey-Musolf, *et al.*

- 17 January 2003

## sin2(W) measurements below Z-pole

- sin2(W) measurements below Z-pole

| e2ePV
11 GeV-Moller Scattering
Q2 = 0.008 GeV2. | DIS-Parity
11 GeV JLab DIS Parity Violation
Q2 = 3.5 GeV2 |
| --- | --- |

- Standard Model predicts sin2(W) 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.

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## Beyond sin2(W):  e.g. SUSY and Dark Matter

**RPV**

**No SUSY dark matter**

- Beyond sin2(W):  *e.g.* SUSY and Dark Matter

- What is Dark Matter?
- S.M.:  QWelectron and QWproton both measure 1-4sin2(W).
- SUSY:  Loop contributions can change this by measurable amounts!

- hep-ph/0205183

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## e2ePV:  Parity Violating Moller Scattering at 12 GeV

- D. Mack, W. van Oers, R. Carlini, N. Simicevic,  G. Smith

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## e2ePV:  Moller Scattering at 12 GeV

- Measurement of QWeak of the electron.
- Very small asymmetry:
-  A|11 GeV **1⁄4** 9**¢**10-7 (1 – 4 sin2W) **1⁄4** 4**¢**10-8.
- Near-vanishing of the tree-level asymmetry makes this measurement sensitive to
- New physics at tree-level (*e.g.* Z**0**),
- 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?

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## Moller sin2 W Error De-Magnification

- sin2(W) **1⁄4** 0.238
- 1 - 4 sin2(W) **1⁄4** 0.05

- Radiative corrections
- Not all of which are suppressed (De-Magnified) by (1-4sin2(W)
- Reduce tree-level Moller asymmetry by **1⁄4** 40%

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## Moller 12 GeV vs. 48 GeV

- Repeat SLAC-E158 Moller
- Figure of merit:
- A2 d/d **/** 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.

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## JLab 12 GeV Moller vs. SLAC E158

- JLab’s advantage comes from the higher integrated luminosity available.

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## Moller sin2(W) Anticipated Uncertainties

- Clearly a competitive measurement of sin2W is possible at 11 GeV which is competitive with the best single measurements below  and at the Z-pole.

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## Moller Detection

- Detector Concept:
- Drift scattered electrons to a collimator.
- Focus electrons in a *resistive* toroidal magnet.
- Drift electrons to detector ring.

- 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

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## 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.

- JLab QWeak (proton) and JLab e2ePV Moller (QWe) anticipated limits.

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## DIS-Parity:  Polarized e- deuterium Deep Inelastic Scattering Parity NonConservation

- Paul Reimer, Peter Bosted, Dave Mack

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## 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 A vs. 4 A at SLAC in ’78	**£** 25 stat
- 60 cm target vs. 30 cm target			**£ ** 2 stat
- Pe (=electron polarization) = 80%  vs. 37% 	**£**  4 stat
-   Pe **1⁄4** 1% vs. 6%					**£**  6 sys

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## DIS-Parity:  Polarized e- deuterium DIS

- Longitudinally polarized electrons on unpolarized isoscaler (deuterium) target.

- Note that each of the Cia are sensitive to *different* possible S.M. extensions.

- C1q **)** NC vector coupling to *q*
-         **£** NC axial coupling to *e*
- C2q **)** NC axial coupling to *q*
-         **£** NC vector coupling to *e*

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## DIS-Parity:  Detector and Expected Rates

- Expt. Assumptions:
- 60 cm ld2/lH2 target
- 11 GeV beam @ 90
- 75% polar.
- 12.5**±** central angle
- 12 msr d
** **6.8 GeV**§**10% mom. bite

- Rate expectations:
-  **1⁄4** 1MHz DIS
-  /e **1⁄4** 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)

**h**x**i** = 0.45  **h**Q**2****i** = 3.5 GeV**2**
**h**Y**i** = 0.46 **h**W**2****i** = 5.23 GeV**2**

- Q2 near NuTeV result—provide cross check on neutrino result.

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## 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% |
| Q2 | 0.5% |
| Radiative corr. | <1% |
| R = (L/T) = § 15% | <0.02% |
| s(x) = § 10% | <0.03% |
| EMC Effect | ???? |
| Higher Twist | ???? |

*What about C**iq**’s?*

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## Extracted Signal—It’s all in the binning

- Note—Polarization uncertainty enters as in slope and intercept
- Aobs = PAd **/** P(2C1u–C1d) + P(2C2u–C2d)Y]
- but is correlated

- PDG:	C1u= –0.209**§**0.041 highly
- 		C1d=   0.358**§**0.037 correlated
- 		2C2u– C2d = –0.08**§**0.24
- This measurement:
- 	(2C1u– C1d) = 0.005 (stat.)
- 	(2C2u– C2d) = 0.014 (stat.)

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## DIS-Parity determines 2C2u-C2d

- Combined result significantly constrains 2C2u–C2d.
- PDG 2C2u–C2d = –0.08 **§** 0.24  Combined (2C2u–C2d) = **§** 0.014
**£** 17 improvement (S.M 2C2u – C2d = 0.0986)

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## 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***

- (2C1u – C1d) = 0.005
- (2C2u – C2d) = 0.014

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003

## JLab tests of the Standard Model 

- Measurements of sin2(W) 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.

**RPV**

**No SUSY dark matter**

- hep-ph/0205183

- Weak Mixing Angle MS-bar scheme
- Jens Erler

- Paul E. Reimer, Argonne National Laboratory

- 17 January 2003