19,491 research outputs found
Two-orbital Systems with Crystal Field Splitting and Interorbital Hopping
The nondegenerate two-orbital Hubbard model is studied within the dynamic
mean-field theory to reveal the influence of two important factors, i.e.
crystal field splitting and interorbital hopping, on orbital selective Mott
transition (OSMT) and realistic compound CaSrRuO. A
distinctive feature of the optical conductivity of the two nondegenerate bands
is found in OSMT phase, where the metallic character of the wide band is
indicated by a nonzero Drude peak, while the insulating narrow band has its
Drude peak drop to zero in the mean time. We also find that the OSMT regime
expands profoundly with the increase of interorbital hopping integrals. On the
contrary, it is shown that large and negative level splitting of the two
orbitals diminishes the OSMT regime completely. Applying the present findings
to compound CaSrRuO, we demonstrate that in the doping
region from to 2.0, the negative level splitting is unfavorable to the
OSMT phase.Comment: 7 pages with 5 figure
Isospin violation in via hadronic loops
In this work, we study the isospin-violating decay of
and quantify the electromagnetic (EM) transitions and intermediate meson
exchanges as two major sources of the decay mechanisms. In the EM decays, the
present datum status allows a good constraint on the EM decay form factor in
the vector meson dominance (VMD) model, and it turns out that the EM transition
can only account for about of the branching ratio for . The intermediate meson exchanges, (intermediate
interaction via exchanges), (intermediate
rescattering via kaon exchanges), and
(intermediate rescattering via exchanges), which evade the
naive Okubo-Zweig-Iizuka (OZI) rule, serve as another important contribution to
the isospin violations. They are evaluated with effective Lagrangians where
explicit constraints from experiment can be applied. Combining these three
contributions, we obtain results in good agreement with the experimental data.
This approach is also extended to , where
we find contributions from the , and
loops are negligibly small, and the isospin violation is
likely to be dominated by the EM transition.Comment: Revised version resubmitted to PRD; Additional loop contributions
included; Conclusion unchange
Effects of interorbital hopping on orbital fluctuations and metal-insulator transitions: Extended linearized dynamical mean-field theory
We study the effects of interorbital hopping on orbital fluctuations and
Mott-Hubbard metal-insulator transition (MIT) in the two-orbital Hubbard model
within the extended linearized dynamical mean-field theory. By mapping the
model onto an effective model with different bandwidths through the canonical
transformation, we find that at half-filling, the increases of the interorbital
Coulomb interaction and the Hund's coupling drive the MIT, and
the critical for MIT increases with the lift of the inter-orbital
hopping integral . Meanwhile at quarter filling and in the strong
correlation regime, the system without exhibits MIT with the
decreasing of , and favors the orbital liquid ground state. However, the
system transits from metal to insulator with the increasing of t,
accompanied with the rising of the orbital order parameter. These results show
the important role of the interorbital hopping in the orbital fluctuation and
orbital ordering.Comment: 7 pages, 6 figure
Heavy Quark Spin Symmetry Violating Hadronic Transitions of Higher Charmonia
In heavy quarkonia, hadronic transitions serve as an enlightened probe for
the structure and help to establish the understanding of light quark coupling
with a heavy degree of freedom. Moreover, in recent years, hadronic transitions
revealed remarkable discoveries to identify the new conventional heavy
quarkonia and extracting useful information about the so called "XYZ" exotic
states. In this contribution, we present our predictions for heavy quark spin
symmetry (HQSS) breaking hadronic transitions of higher and wave vector
charmonia based on our recently proposed model (inspired by Nambu-Jona-Lasinio
(NJL) model) to create light meson(s) in heavy quarkonium transitions. We also
suggest spectroscopic quantum numbers for several observed
charmoniumlike states. Our analysis indicates that the is most likely
to be a dominant state.Comment: Proceedings of the talk presented at "XVII International Conference
on Hadron Spectroscopy and Structure (Hadron2017)", 25-29 September 2017,
Salamanca, Spai
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