13,162 research outputs found
Strong decays of and
With the identification of () as the (,
) doublet in the heavy quark effective field theory, we derive the light
cone QCD sum rule for the coupling of eta meson with and
. Through mixing we calculate their pionic
decay widths, which are consistent with the experimental values (or upper
limits). Combining the radiative decay widths derived by Colangelo, Fazio and
Ozpineci in the same framework, we conclude that the decay patterns of
strongly support their interpretation as ordinary mesons.Comment: Comments and suggestions welcome
Manipulating non-reciprocity in a two-dimensional magnetic quantum walk
Non-reciprocity is an important topic in fundamental physics and
quantum-device design, as much effort has been devoted to its engineering and
manipulation. Here we experimentally demonstrate non-reciprocal transport in a
two-dimensional quantum walk of photons, where the directional propagation is
highly tunable through dissipation and synthetic magnetic flux. The
non-reciprocal dynamics hereof is a manifestation of the non-Hermitian skin
effect, with its direction continuously adjustable through the photon-loss
parameters. By contrast, the synthetic flux originates from an engineered
geometric phase, which competes with the non-Hermitian skin effect through
magnetic confinement. We further demonstrate how the non-reciprocity and
synthetic flux impact the dynamics of the Floquet topological edge modes along
an engineered boundary. Our results exemplify an intriguing strategy for
achieving tunable non-reciprocal transport, highlighting the interplay of
non-Hermiticity and gauge fields in quantum systems of higher dimensions.Comment: 9 pages, 6 figure
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