6,839 research outputs found
Correlation of circular differential optical absorption with geometric chirality in plasmonic meta-atoms
We report a strong correlation between the calculated broadband circular differential optical absorption (CDOA) and the geometric chirality of plasmonic meta-atoms with two-dimensional chirality. We investigate this correlation using three common gold meta-atom geometries: L-shapes, triangles, and nanorod dimers, over a broad range of geometric parameters. We show that this correlation holds for both contiguous plasmonic meta-atoms and non-contiguous structures which support plasmonic coupling effects. A potential application for this correlation is the rapid optimization of plasmonic nanostructure for maximum broadband CDOA
Lepton flavor violating decays of vector mesons
We estimate the rates of lepton flavor violating decays of the vector mesons
. The theoretical tools are based on an effective
Lagrangian approach without referring to any specific realization of the
physics beyond the standard model responsible for lepton flavor violation
(\Lfv). The effective lepton-vector meson couplings are extracted from the
existing experimental bounds on the nuclear conversion. In
particular, we derive an upper limit for the \Lfv branching ratio which is much more stringent than
the recent experimental result
presented by the SND Collaboration. Very tiny limits on \Lfv decays of vector
mesons derived in this letter make direct experimental observation of these
processes unrealistic.Comment: 3 pages, 1 figure, accepted for publication in Phys. Rev.
Hadronic and radiative three-body decays of J/psi involving the scalars f0(1370), f0(1500) and f0(1710)
We study the role of the scalar resonances f0(1370), f0(1500) and f0(1710) in
the strong and radiative three-body decays of J/psi with J/psi to V + P P
(gamma gamma) and J/psi to gamma + P P (V V), where P (V) denotes a
pseudoscalar (vector) meson. We assume that the scalars result from a
glueball-quarkonium mixing scheme while the dynamics of the transition process
is described in an effective chiral Lagrangian approach. Present data on J/psi
to V + P P are well reproduced, predictions for the radiative processes serve
as further tests of this scenario.Comment: 15 page
New bounds on lepton flavor violating decays of vector mesons and the Z0 boson
We give an estimate for the upper bounds on rates of lepton flavor violating
(LFV) decays M to mu(pm) + e(mp) of vector mesons M = rho0, omega, phi, J/psi,
Upsilon and the Z0 boson in a model independent way, analyzing the
corresponding lowest dimension effective operators. These operators also
contribute to nuclear mu-e-conversion. Based on this observation and using the
existing experimental limits on this LFV nuclear process, we show that the
studied two-body LFV decays of vector bosons are strongly suppressed
independent on the explicit realization of new physics. The upper limits on the
rates of some of these decays are significantly more stringent than similar
limits known in the literature. In view of these results experimental
observation of the two-body LFV decays of vector bosons looks presently
unrealistic.Comment: 4 pages, 1 figur
Electron-Positron Annihilation into Hadron-Antihadron Pairs
The reactions of electron-positron to nucleon-antinucleon pairs are studied
in a non-perturbative quark model. The work suggests that the two-step process,
in which the primary quark-antiquark pair forms first a vector meson which in
turn decays into a hadron pair, is dominant over the one-step process in which
the primary quark-antiquark pair is directly dressed by additional
quark-antiquark pairs to form a hadron pair. To reproduce the experimental data
of the reactions of electron-positron to proton-antiproton and
electron-positron to neutron-antineutron a D-wave omega-like vector meson with
a mass of around 2 GeV has to be introduced.Comment: 15 pages, 6 figure
Note on Scalar Mesons
Review article about the light scalar mesons, experimental and theoretical advances during the previous two years. The nature of several scalar mesons is controversial and they include exotic objects like glue-balls. The note is published in the Review of Particle Properties
Decays of tensor mesons and the tensor glueball in an effective field approach
The strong and electromagnetic decays of the ground-state tensor mesons are
studied in an effective field approach. A fit to the well-known experimental
data is performed. The decay ratios of the tensor glueball are evaluated and
possible candidates are discussed.Comment: 12 page
Updated analysis of meson-nucleon sigma terms in the perturbative chiral quark model
We present an updated analysis of meson-baryon sigma terms in the
perturbative chiral quark model, which is based on effective chiral Lagrangian.
The new feature concerns the inclusion of excited states in the quark
propagator. Its influence on meson loops is shown to lead in particular for the
pion-nucleon sigma term to an enhancement relevant for the current evaluation
of this quantity. We also determine various flavor combinations of the scalar
nucleon form factors and their respective low-momentum transfer limits.Comment: 26 pages, 10 figures, to be published in Phys Rev
Effective Lagrangian approach to nuclear mu-e conversion and the role of vector mesons
We study nuclear mu-e conversion in the general framework of an effective
Lagrangian approach without referring to any specific realization of the
physics beyond the standard model (SM) responsible for lepton flavor violation
(LFV). We examine the impact of a specific hadronization prescription on the
analysis of new physics in nuclear mu-e conversion and stress the importance of
vector meson exchange between lepton and nucleon currents. A new issue of this
mechanism is the presence of the strange quark vector current contribution
induced by the phi meson. This allows us to extract new limits on the LFV
lepton-quark effective couplings from the existing experimental data.Comment: 19 pages, 3 figures, to be published in Phys Rev
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