69 research outputs found
Particle interference as a test of Lorentz-violating electrodynamics
In Lorentz-violating electrodynamics a steady current (and similarly a static
charge) generates both static magnetic and electric fields. These induced
fields, acting on interfering particles, change the interference pattern. We
find that particle interference experiments are sensitive to small Lorentz
violating effects, and thus they can be used to improve current bounds on some
Lorentz-violating parameters.Comment: 5 page
Charmed scalar resonances -- Conventional and four-quark mesons
We propose that there coexist two scalar mesons of different structures (a
conventional meson and a four-quark meson) in the recently observed broad bumps
just below the large peak of the tensor meson in the D-pi mass distribution. We
base this proposal on the interpretation of the charm-strange scalar meson of
mass 2317 MeV as a four-quark meson. The strange counterparts of these scalar
mesons are also studied.Comment: 4 pages, 0 figures, Revte
The Foldy-Wouthuysen transformation
The Foldy-Wouthuysen transformation of the Dirac Hamiltonian is generally
taught as simply a mathematical trick that allows one to obtain a two-component
theory in the low-energy limit. It is not often emphasized that the transformed
representation is the only one in which one can take a meaningful *classical
limit*, in terms of particles and antiparticles. We briefly review the history
and physics of this transformation.Comment: Standard LaTeX, 6 page
Electromagnetic Deflection of Spinning Particles
We show that it is possible to obtain self-consistent and physically
acceptable relativistic classical equations of motion for a point-like
spin-half particle possessing an electric charge and a magnetic dipole moment,
directly from a manifestly covariant Lagrangian, if the classical degrees of
freedom are appropriately chosen. It is shown that the equations obtained
encompass the well-tested Lorentz force and Thomas--Bargmann--Michel--Telegdi
spin equations, as well as providing a definite specification of the classical
_magnetic_dipole_ force_, whose exact form has been the subject of recent
debate. Radiation reaction---the force and torque on an accelerated particle
due to its self-interaction---is neglected at this stage.Comment: 18 pp. (latex, uses revtex 3), UM-P-92/9
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