950 research outputs found
Neutrino propagation in media and axis of complete polarization
We construct a spectral representation of neutrino propagator in moving
matter or in external magnetic field. In both cases there exists fixed
four-dimensional axis of polarization, such that the corresponding spin
projectors commute with propagator. As a result, all eigenvalues of propagator
and, consequently, dispersion laws for neutrino in media are classified
according to spin projection onto this axis. Use of the found spin projectors
simplifies essentially the eigenvalue problem and allows to build spectral
representation of propagator in moving matter or external magnetic field in
analogy with the vacuum propagator.Comment: 16 pages, journal versio
Measurement of the neutron electric dipole moment by crystal diffraction
An experiment using a prototype setup to search for the neutron electric
dipole moment by measuring spin-rotation in a non-centrosymmetric crystal
(quartz) was carried out to investigate statistical sensitivity and systematic
effects of the method. It has been demonstrated that the concept of the method
works. The preliminary result of the experiment is ecm. The experiment showed that an accuracy of ecm can be obtained in 100 days data taking, using available
quartz crystals and neutron beams.Comment: 13 pages, 4 figure
Frequency shifts in gravitational resonance spectroscopy
Quantum states of ultracold neutrons in the gravitational field are to be
characterized through gravitational resonance spectroscopy. This paper
discusses systematic effects that appear in the spectroscopic measurements. The
discussed frequency shifts, which we call Stern-Gerlach shift, interference
shift, and spectator state shift, appear in conceivable measurement schemes and
have general importance. These shifts have to be taken into account in
precision experiments
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