3 research outputs found
Effective Hadron Dynamics: From Meson Masses to the Proton Spin Puzzle
We construct a three flavor chiral Lagrangian of pseudoscalars and vectors
with special emphasis on the symmetry breaking terms. Comparing tree level two
and three point functions with experiment allows us to first, fix the
parameters of the model (including the light quark mass ratios) and second, to
predict and
. The last mentioned quantities come
out reasonably well, in contrast to an ``ordinary" treatment. For this
purpose we need ``second order" symmetry breakers involving the vector fields
analogous to those needed for the chiral perturbation theory program with only
pseudoscalars. An improved description of the system is also
given. We then use the soliton sector of this improved chiral Lagrangian to
investigate some aspects of baryon physics which are especially sensitive to
symmetry breaking. For this purpose a fairly elaborate ``cranking" techinque is
employed in connection with the collective Hamiltonian. In addition to the
``strong" baryon mass spectrum a careful investigation is made of the
non-electromagnetic part of the neutron-proton mass difference. This work is
needed to improve our previous estimates concerning the two component approach
to the ``proton spin" puzzle. We find that both the ``matter" and ``glue"
contributions are small but they do tend to cancel each other.Comment: 33 pages, LaTe
Semileptonic lepton number / flavor violating tau decays in Majorana neutrino models
Motivated by the recent investigation of neutrinoless -lepton decays by
the CLEO collaboration, we perform a systematic analysis of such decays in a
possible new-physics scenario with heavy Dirac/Majorana neutrinos, including
heavy-neutrino nondecoupling effects, finite quark masses, and quark as well as
meson mixings. We find that -lepton decays into an electron or muon and a
pseudoscalar or vector meson can have branching ratios close to the
experimental sensitivity. Numerical estimates show that the predominant decay
modes of this kind are , , and
, with branching ratios of order .Comment: LaTeX, 24 pages, minor rewordings