Measurement of the Neutron Radius of 208Pb Through Parity Violation in Electron Scattering
Abstract
In contrast to the nuclear charge densities, which have been accurately measured with electron scattering, the knowledge of neutron densities still lack precision. Previous model-dependent hadron experiments suggest the difference between the neutron radius, Rn, of a heavy nucleus and the proton radius, Rp, to be in the order of several percent. To accurately obtain the difference, Rn-Rp, which is essentially a neutron skin, the Jefferson Lab Lead (208Pb) Radius Experiment (PREX) measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from 208Pb at an energy of 1.06 GeV and a scattering angle of 5° . Since Z0 boson couples mainly to neutrons, this asymmetry provides a clean measurement of Rn with respect to Rp. PREX was conducted at the Jefferson lab experimental Hall A, from March to June 2010. The experiment collected a final data sample of 2x 107 helicity-window quadruplets. The measured parity-violating electroweak asymmetry APV = 0.656 ± 0.060 (stat) ± 0.014 (syst) ppm corresponds to a difference between the radii of the neutron and proton distributions, Rn-Rp = 0.33+0.16-0.18 fm and provides the first electroweak observation of the neutron skin as expected in a heavy, neutron-rich nucleus. The value of the neutron radiusmore »
- Authors:
-
- Univ. of Virginia, Charlottesville, VA (United States)
- Publication Date:
- Research Org.:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- OSTI Identifier:
- 1079207
- Report Number(s):
- JLAB-PHY-13-1731; DOE/OR/23177-2553
- DOE Contract Number:
- AC05-06OR23177
- Resource Type:
- Thesis/Dissertation
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Citation Formats
Saenboonruang, Kiadtisak. Measurement of the Neutron Radius of 208Pb Through Parity Violation in Electron Scattering. United States: N. p., 2013.
Web. doi:10.2172/1079207.
Saenboonruang, Kiadtisak. Measurement of the Neutron Radius of 208Pb Through Parity Violation in Electron Scattering. United States. https://doi.org/10.2172/1079207
Saenboonruang, Kiadtisak. 2013.
"Measurement of the Neutron Radius of 208Pb Through Parity Violation in Electron Scattering". United States. https://doi.org/10.2172/1079207. https://www.osti.gov/servlets/purl/1079207.
@article{osti_1079207,
title = {Measurement of the Neutron Radius of 208Pb Through Parity Violation in Electron Scattering},
author = {Saenboonruang, Kiadtisak},
abstractNote = {In contrast to the nuclear charge densities, which have been accurately measured with electron scattering, the knowledge of neutron densities still lack precision. Previous model-dependent hadron experiments suggest the difference between the neutron radius, Rn, of a heavy nucleus and the proton radius, Rp, to be in the order of several percent. To accurately obtain the difference, Rn-Rp, which is essentially a neutron skin, the Jefferson Lab Lead (208Pb) Radius Experiment (PREX) measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from 208Pb at an energy of 1.06 GeV and a scattering angle of 5° . Since Z0 boson couples mainly to neutrons, this asymmetry provides a clean measurement of Rn with respect to Rp. PREX was conducted at the Jefferson lab experimental Hall A, from March to June 2010. The experiment collected a final data sample of 2x 107 helicity-window quadruplets. The measured parity-violating electroweak asymmetry APV = 0.656 ± 0.060 (stat) ± 0.014 (syst) ppm corresponds to a difference between the radii of the neutron and proton distributions, Rn-Rp = 0.33+0.16-0.18 fm and provides the first electroweak observation of the neutron skin as expected in a heavy, neutron-rich nucleus. The value of the neutron radius of 208Pb has important implications for models of nuclear structure and their application in atomic physics and astrophysics such as atomic parity non-conservation (PNC) and neutron stars.},
doi = {10.2172/1079207},
url = {https://www.osti.gov/biblio/1079207},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed May 01 00:00:00 EDT 2013},
month = {Wed May 01 00:00:00 EDT 2013}
}