(Introduction)
- The poem by John Updike,
Neutrinos they are very small
They have no charge and have no mass
And do not interact at all.....
(Contemporary Issues)
- 1) Use of neutrino scattering in order to study the Q² evolution of deep inelastic structure functions as a test of perturbative QCD.
- 2) Use of such deep inelastic structure functions in order to check the valadity of various sum rules.
Two of the issues are well known. So the author discussed 3 of the following applications of neutrino studies.
- 1) Goldberger-Treiman Discrepancy
- 2) Axial Charge Radius
- 3) Nucleon Strangeness Content
1) Goldberger-Treiman Discrepancy: In QCD, (borken) Chiral symmetry implies the existence of the Goldberger-Treiman (GT) relation, which connects the strong pion-nucleon coupling g_{πNN} and the axial coupling g_{A}(0) measured in neutron beta decay, where
- M_{N}g_{A}(0) = F_{π}g_{πNN}(0)
where F_{π} = 92.3 MeV is the pion decay constant.
2) Axial Charge Radius: Neutrino scattering result associated with confirmation of a prediction of Chiral perturbation theory and therefore of QCD.
Recent calculation by Bernard, Kaiser, and Meissner in heavy Baryon chiral perturbation theory implies that the old low energy theorem is incorrect.
Using triangle diagram,
- r²_{A}(elec.) = r²_{A}(neu.) - (3/64)(1/F²_{π})(12/π² - 1)
Result: Prediction of 0.046fm² difference from chiral symmetry agrees well in size and sign with that seen experimentally.
3) Nucleon Strangeness Content: the paper of Donoghue and Nappi is wrong. IDEA: In the limit of vanishing quark masses the nucleon mass should approach some nonzero value M_{0}.