Measuring the neutron's mean square charge radius using neutron interferometry

✍ Scribed by F.E. Wietfeldt; M. Huber; T.C. Black; H. Kaiser; M. Arif; D.L. Jacobson; S.A. Werner

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 153 KB
• Volume: 385-386
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2006.05.187

✦ Synopsis

The neutron is electrically neutral, but its substructure consists of charged quarks so it may have an internal charge distribution. In fact it is known to have a negative mean square charge radius (MSCR), the second moment of the radial charge density. In other words the neutron has a positive core and negative skin. In the first Born approximation the neutron MSCR can be simply related to the neutron-electron scattering length b ne . In the past this important quantity has been extracted from the energy dependence of the total transmission cross-section of neutrons on high-Z targets, a very difficult and complicated process. A few years ago S.A. Werner proposed a novel approach to measuring b ne from the neutron's dynamical phase shift in a perfect crystal close to the Bragg condition. We are conducting an experiment based on this method at the NIST neutron interferometer which may lead to a five-fold improvement in precision of b ne and hence the neutron MSCR.