43 research outputs found
Spin alignment of mesons produced in neutron-carbon interactions
A new precise measurements of spin density matrix element of
mesons produced inclusively in neutron-carbon interactions at
\~60 GeV have been carried out in the EXCHARM experiment at the Serpukhov
accelerator. The values of obtained in the transversity frame are
for and
for . Significant
dependence of has been observed in production.Comment: 8 pages, LaTeX, 3 eps figure
Spontaneous Lorentz Violation via QED with Non-Exact Gauge Invariance
We reconsider an alternative theory of the QED with the photon as a massless
vector Nambu-Goldstone boson and show that the underlying spontaneous Lorentz
violation caused by the vector field vacuum expectation value, while being
superficial in gauge invariant theory, becomes physically significant in the
QED with a tiny gauge non-invariance. This leads, through special dispersion
relations appearing for charged fermions, to a new class of phenomena which
could be of distinctive observational interest in particle physics and
astrophysics. They include a significant change in the GZK cutoff for UHE
cosmic-ray nucleons, stability of high-energy pions and W bosons, modification
of nucleon beta decays, and some others.Comment: 15 pages, to appear in Eur.Phys.J.