scholarly journals Measurement of the Neutron Radius of 208Pb Through Parity Violation in Electron Scattering

2013 ◽  
Author(s):  
Kiadtisak Saenboonruang
Keyword(s):  
Electron Scattering ◽  
Parity Violation ◽  
Neutron Radius

scholarly journals Measurement of the Neutron Radius ofPb208through Parity Violation in Electron Scattering

2012 ◽  
Vol 108 (11) ◽  
Author(s):  
S. Abrahamyan ◽  
Z. Ahmed ◽  
H. Albataineh ◽  
K. Aniol ◽  
D. S. Armstrong ◽  
...  
Keyword(s):  
Electron Scattering ◽  
Parity Violation ◽  
Neutron Radius

EXPERIMENT PREX AT TJNAF: A MODEL-INDEPENDENT MEASUREMENT OF THE NEUTRON RADIUS IN 208Pb

2010 ◽  
Vol 19 (05n06) ◽  
pp. 1084-1095
Author(s):  
◽  
G. M. URCIUOLI
Keyword(s):  
Electron Scattering ◽  
Cross Sections ◽  
Parity Violation ◽  
Heavy Ion ◽  
Independent Measurement ◽  
Ion Collisions ◽  
Neutron Radius ◽  
Left Handed ◽  
Model Independent

Experiment PREX will take place in Hall A at TJNAF in 2010. It will measure the neutron radius Rn in the 208 Pb nucleus through the measurement of the parity violating asymmetry in electron scattering [Formula: see text], with σR and σL the cross sections for right handed and left handed electrons respectively. The projected accuracy of 1% on Rn constitutes a fundamental test of nuclear theory. This measurement of Rn will provide the best determination of the density dependence of the symmetry energy at the density of ordinary nuclear matter. As a consequence, the PREX result will have a big impact on phenomena like neutron star structure, heavy ion collisions and atomic parity violation.

scholarly journals FROM HADRONIC PARITY VIOLATION TO PARITY-VIOLATING ELECTRON SCATTERING AND TESTS OF THE STANDARD MODEL

2008 ◽  
Vol 23 (17n20) ◽  
pp. 1266-1277 ◽  
Author(s):  
WILLEM T. H. VAN OERS
Keyword(s):  
Standard Model ◽  
Electron Scattering ◽  
Parity Violation ◽  
New Physics ◽  
Theoretical Interpretation ◽  
Weak Mixing Angle ◽  
Weak Mixing ◽  
Mixing Angle ◽  
The Standard Model ◽  
Analyzing Power

Searches for parity violation in hadronic systems started soon after the evidence for parity violation in β-decay of 60 Co was presented by Madame Chien-Shiung Wu and in π and μ decay by Leon Lederman in 1957. The early searches for parity violation in hadronic systems did not reach the sensitivity required and only after technological advances in later years was parity violation unambiguously established. Within the meson-exchange description of the strong interaction, theory and experiment meet in a set of seven weak meson-nucleon coupling constants. Even today, after almost five decades, the determination of the seven weak meson-nucleon couplings is incomplete. Parity violation in nuclear systems is rather complex due to the intricacies of QCD. More straight forward in terms of interpretation are measurements of the proton-proton parity-violating analyzing power (normalized differences in scattering yields for positive and negative helicity incident beams), for which there exist three precision experiments (at 13.6, at 45, and 221 MeV). To-date, there are better possibilities for theoretical interpretation using effective field theory approaches. The situation with regard to the measurement of the parity-violating analyzing power or asymmetry in polarized electron scattering is quite different. Although the original measurements were intended to determine the electro-weak mixing angle, with the current knowledge of the electro-weak interaction and the great precision with which electro-weak radiative corrections can be calculated, the emphasis has been to study the structure of the nucleon, and in particular the strangeness content of the nucleon. A whole series of experiments (the SAMPLE experiment at MIT-Bates, the G0 experiment and HAPPEX experiments at Jefferson Laboratory (JLab), and the PVA4 experiment at MAMI) have indicated that the strange quark contributions to the charge and magnetization distributions of the nucleon are tiny. These measurements if extrapolated to zero degrees and zero momentum transfer have also provided a factor five improvement in the knowledge of the neutral weak couplings to the quarks. Choosing appropriate kinematics in parity-violating electron-proton scattering permits nucleon structure effects on the measured analyzing power to be precisely controlled. Consequently, a precise measurement of the ‘running’ of sin 2θw or the electro-weak mixing angle has become within reach. The [Formula: see text] experiment at Jefferson Laboratory is to measure this quantity to a precision of about 4%. This will either establish conformity with the Standard Model of quarks and leptons or point to New Physics as the Standard Model must be encompassed in a more general theory required, for instance, by a convergence of the three couplings (strong, electromagnetic, and weak) to a common value at the GUT scale. The upgrade of CEBAF at Jefferson Laboratory to 12 GeV, will allow a new measurement of sin 2θW in parity-violating electron-electron scattering with an improved precision to the current better measurement (the SLAC E158 experiment) of the ‘running’ of sin 2θW away from the Z0 pole. Preliminary design studies of such an experiment show that a precision comparable to the most precise individual measurements at the Z0 pole (to about ±0.00025) can be reached. The result of this experiment will be rather complementary to the [Formula: see text] experiment in terms of sensitivity to New Physics.

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