College Park, Maryland June 6 - 10 , 2004 |
TP43: Some Principal Problems in Physics and Neutron Low Energy Physics
Yu. A. Alexandrov (Senior Scientist of FLNP, JINR, Dubna)
Physics is a single whole, therefore the answers to some principal questions should be sought for not only in high-energy physics, but also in other divisions of physics, e.g. in low energy neutron physics. Especially since the accuracy of experiments in neutron physics is frequently much higher.
In this report the questions connected with the internal structure of particles (e.g. of neutron) are discussed.
The first question deals with the charge neutron radius connected with the value of neutron-electron scattering length determined at low neutron energies. At present, the obtained accuracy allows us to speak not only about the value of the charge neutron radius, but also on the division of it into Dirac and Foldy terms. The sign of the Dirac term is connected directly with the fundamental Yukawa theory explaining the origin of nuclear forces.
The second question also concerns the subject of the structure of the neutron, namely its deformation. The notion of deformation (polarizability) of the nucleon in electromagnetic field was introduced in mid 50s. In the report the reasons are given in favor of the opinion that the neutron polarizability was observed for the first time in neutron experiments already in 1957, i.e. earlier than the proton polarizability was detected (1960).
Finally, the third question deals with the search for a magnetic charge of the neutron. The beautiful experiment (Finkelstein, Shull, Zeilinger, 1986) testifying with high accuracy the absence of a magnetic charge of the neutron is discussed. The existence of an isolated magnetic charge in the nature would explain the quantization of electric and magnetic charges (Dirac, 1931).
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