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Title: Parity violation in deep inelastic scattering at JLab 6 GeV.

Abstract

The parity-violating asymmetry in e-2H deep inelastic scattering (DIS) can be used to extract the weak neutral-current coupling constants C 2q . A measurement of this asymmetry at two Q 2 values is planned at Jefferson Lab. Results from this experiment will provide a value of 2C 2u - C 2d to a precision of {+-}0.03, a factor of eight improvement over our current knowledge. If all hadronic effects can be understood, this result will provide information on possible extensions of the Standard Model, complementary to other experiments dedicated to new physics searches. Presented here are the physics motivation, experimental setup, potential hadronic effects and their implications, and the future of PV DIS at Jefferson Lab.

Authors:
; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
983749
Report Number(s):
ANL/PHY/CP-119296
TRN: US1005367
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Conference
Resource Relation:
Conference: 3rd International Workshop from Parity Violation to Hadronic Structure (PAVI 2006); May 16, 2006 - May 20, 2006; Milos, Greece
Country of Publication:
United States
Language:
ENGLISH
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ACCURACY; ASYMMETRY; COUPLING CONSTANTS; DEEP INELASTIC SCATTERING; PARITY; POTENTIALS; STANDARD MODEL; VIOLATIONS; WEAK NEUTRAL CURRENTS

Citation Formats

Zheng, X., Arrington, J., Geesaman, D. F., Hafidi, K., Holt, R. J., Jackson, H. E., Potterveld, D. H., Reimer, P. E., Schulte, E., Zeidman, B., and Physics. Parity violation in deep inelastic scattering at JLab 6 GeV.. United States: N. p., 2007. Web. doi:10.1007/978-3-540-74413-9_40.
Zheng, X., Arrington, J., Geesaman, D. F., Hafidi, K., Holt, R. J., Jackson, H. E., Potterveld, D. H., Reimer, P. E., Schulte, E., Zeidman, B., & Physics. Parity violation in deep inelastic scattering at JLab 6 GeV.. United States. doi:10.1007/978-3-540-74413-9_40.
Zheng, X., Arrington, J., Geesaman, D. F., Hafidi, K., Holt, R. J., Jackson, H. E., Potterveld, D. H., Reimer, P. E., Schulte, E., Zeidman, B., and Physics. Mon . "Parity violation in deep inelastic scattering at JLab 6 GeV.". United States. doi:10.1007/978-3-540-74413-9_40.
@article{osti_983749,
title = {Parity violation in deep inelastic scattering at JLab 6 GeV.},
author = {Zheng, X. and Arrington, J. and Geesaman, D. F. and Hafidi, K. and Holt, R. J. and Jackson, H. E. and Potterveld, D. H. and Reimer, P. E. and Schulte, E. and Zeidman, B. and Physics},
abstractNote = {The parity-violating asymmetry in e-2H deep inelastic scattering (DIS) can be used to extract the weak neutral-current coupling constants C 2q . A measurement of this asymmetry at two Q 2 values is planned at Jefferson Lab. Results from this experiment will provide a value of 2C 2u - C 2d to a precision of {+-}0.03, a factor of eight improvement over our current knowledge. If all hadronic effects can be understood, this result will provide information on possible extensions of the Standard Model, complementary to other experiments dedicated to new physics searches. Presented here are the physics motivation, experimental setup, potential hadronic effects and their implications, and the future of PV DIS at Jefferson Lab.},
doi = {10.1007/978-3-540-74413-9_40},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

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  • The parity-violating asymmetry in e-more » $^2$H deep inelastic scattering (DIS) can be used to extract the weak neutral-current coupling constants $$C_{2q}$$. A measurement of this asymmetry at two $Q^2$ values is planned at Jefferson Lab. Results from this experiment will provide a value of $$2C_{2u}-C_{2d}$$ to a precision of $$\pm 0.03$$, a factor of eight improvement over our current knowledge. If all hadronic effects can be understood, this results will provide information on possible extensions of the Standard Model, complementary to other experiments dedicated to new physics searches. Presented here are the physics motivation, experimental setup, potential hadronic effects and their implications, and the future of PV DIS at Jefferson Lab.« less
  • The couplings of leptons to quarks are fundamental parameters of the electroweak interaction. Within the framework of the Standard Model, these couplings can be related to sin{sup 2} {theta}{sub W}. Parity violation (PV) in deep inelastic scattering (DIS) is proportional to these couplings and hence sensitive to sin{sup 2} {theta}{sub W}. PV-DIS, first measured at SLAC in the mid-1970's, was used to establish the Standard Model. The high quality and intensity of the upgraded 11 GeV CEBAF beam at Jefferson Laboratory will make it an ideal tool for PV studies. In DIS the asymmetry from parity violation is large (A{submore » PV} {approx} 10{sup -4} Q{sup 2}), allowing precise measurements with modest beam time. This talk will explore a PV-DIS measurement which can be made using the baseline spectrometers that will exist as part of the 12 GeV JLab upgrade.« less
  • The program proposed contains two ingredients which aim to address aspects of two of the three research frontiers of nuclear science as identified in the 2007 NSAC Long Range Plan. The first topic, a test of the current Standard Model, is an ongoing project focusing on measurements of the parity-violating asymmetry in ~e-2H deep inelastic scattering (PVDIS). The PVDIS measurement is complementary to other completed or ongoing low- to medium-energy tests of the Standard Model. As the first, exploratory, step, an experiment using a 6 GeV electron beam will be carried out from October to December 2009 at the Thomasmore » Jefferson National Accelerator Facility (JLab). Meanwhile, a program using the upgraded JLab 11 GeV beam is being planned. The PVDIS program as a whole will provide the first precision data on the axial quark neutral-weak coupling constants. This will either put the current Standard Model to a test that has never been done before, or reveal information on where to look for New Physics beyond the current Standard Model. The PVDIS program will also provide results on hadronic physics effects such as charge symmetry violation. The second part of the proposed program uses spin observables to address the research frontier concerning QCD and structure of the nucleon. An experiment using the JLab 6 GeV beam in 2001 showed that, contrary to predictions from perturbative quantum chromodynamics (pQCD), while the valence up quark’s spin is parallel to the nucleon’s spin, the valence down quark’s spin is not. In order to test the limit of QCD in describing the nucleon spin structure to a region beyond the 6 GeV kinematics, this measurement will be extended to a more energetic, “deeper” valence quark region using the upgraded JLab 11 GeV beam with a polarized 3He target. Although the two topics of the proposed program appear to focus on different physics, for the upgraded JLab 11 GeV beam, both will utilize a new, yet-to-be-built large acceptance spectrometer, called “SoLID”. Once built, SoLID can be used for other topics such as using PVDIS on a proton target to measure the valence quark distributions, using PVDIS on a polarized target to measure new electro-weak interference structure functions of the nucleon, and semi-inclusive deep inelastic scattering experiments. SoLID will greatly enhance the exploration potential of JLab. The proposed program will first focus on completion of the 6 GeV PVDIS experiment, its data analysis and publishing physics results. This 6 GeV experiment will explore whether precision PVDIS measurements are feasible, will set limits on the hadronic physics effects, and will improve our knowledge on the quark neutral weak couplings, optimally by a factor of six. Starting early 2010, efforts will be spent on preparation for the 11 GeV program, focusing on simulations of SoLID, optimization and construction of the SoLID detector package, and studies of the polarized 3He target and its improvements. Funding support for the whole program is requested here.« less
  • The parity-violating asymmetry in deep inelastic scattering (PVDIS) offers us a useful tool to study the weak neutral couplings and the hadronic structure of the nucleon, and provides high precision tests on the Standard Model. During the 6 GeV PVDIS experiment at the Thomas Jefferson National Accelerator Facility, the parity-violating asymmetries A{sub PV} of a polarized electron beam scattering off an unpolarized deuteron target in the deep inelastic scattering region were precisely measured at two Q 2 values of 1.1 and 1.9 (GeV/c) 2. The asymmetry at Q 2=1.9 (GeV/c) 2 can be used to extract the weak coupling combinationmore » 2C 2u - C 2d, assuming the higher twist effect is small. The extracted result from this measurement is in good agreement with the Standard Model prediction, and improves the precision by a factor of five over previous data. In addition, combining the asymmetries at both Q 2 values provides us extra knowledge on the higher twist effects. The parity violation asymmetries in the resonance region were also measured during this experiment. These results are the first A PV data in the resonance region beyond the Δ (1232). They provide evidence that the quark hadron duality works for A PV at the (10-15)% level, and set constraints on nucleon resonance models that are commonly used for background calculations to other parity-violating electron scattering measurements.« less
  • We report on the measurement of parity-violating asymmetries in the deep inelastic scattering and nucleon resonance regions using inclusive scattering of longitudinally polarized electrons from an unpolarized deuterium target. The effective weak couplings Cmore » $$_{2q}$$ are accessible through the deep-inelastic scattering measurements. Here we report a measurement of the parity-violating asymmetry, which yields a determination of 2C$$_{2u}$$ - C$$_{2d}$$ with an improved precision of a factor of five relative to the previous result. This result indicates evidence with 95% confidence that the 2C$$_{2u}$$ - C$$_{2d}$$ is non-zero. This experiment also provides the first parity-violation data covering the whole resonance region, which provide constraints on nucleon resonance models. Finally, the program to extend these measurements at Jefferson Lab in the 12 GeV era using the Solenoidal Large Intensity Device was also discussed.« less