13,528 research outputs found
The reactions p + n --> d + omega and p + n --> d + phi near threshold
The reactions p+n-->d+omega and p+n-->d+phi are studied within a relativistic
meson-exchange model of hadronic interactions. Predictions for the total cross
sections and for the angular distributions of the vector mesons are presented.
The resulting cross sections near threshold are around 10 - 30 microb for
p+n-->d+omega$ and 200 - 250 nb for p+n-->d+phi. A moderate deviation of the
cross section ratio sigma_{p+n-->d+phi} / sigma_{p+n-->d+omega} from that of
the Okubo-Zweig-Iizuka rule is predicted.Comment: 12 pages, 7 figure
Non-critical open strings beyond the semi-classical approximation
We studied the lowest order quantum corrections to the macroscopic wave
functions of non-critical string theory using the
semi-classical expansion of Liouville theory. By carefully taking the perimeter
constraint into account we obtained a new type of boundary condition for the
Liouville field which is compatible with the reparametrization invariance of
the boundary and which is not only a mixture of Dirichlet and Neumann types but
also involves an integral of an exponential of the Liouville field along the
boundary. This condition contains an unknown function of . We
determined this function by computing part of the one-loop corrections to
.Comment: 23 pages, 1 figure, LaTeX file, epsf.st
Analyzing eta' photoproduction data on the proton at energies of 1.5--2.3 GeV
The recent high-precision data for the reaction at
photon energies in the range 1.5--2.3 GeV obtained by the CLAS collaboration at
the Jefferson Laboratory have been analyzed within an extended version of the
photoproduction model developed previously by the authors based on a
relativistic meson-exchange model of hadronic interactions [Phys. Rev. C
\textbf{69}, 065212 (2004)]. The photoproduction can be described quite
well over the entire energy range of available data by considering ,
, , and resonances, in addition to the -channel
mesonic currents. The observed angular distribution is due to the interference
between the -channel and the nucleon - and -channel resonance
contributions. The resonances are required to reproduce some of the
details of the measured angular distribution. For the resonances considered,
our analysis yields mass values compatible with those advocated by the Particle
Data Group. We emphasize, however, that cross-section data alone are unable to
pin down the resonance parameters and it is shown that the beam and/or target
asymmetries impose more stringent constraints on these parameter values. It is
found that the nucleonic current is relatively small and that the
coupling constant is not expected to be much larger than 2.Comment: Revised version based on revised (finalized) CLAS data (14 pages, 10
figures, RevTeX4
Role of high-spin hyperon resonances in the reaction of
The recent data taken by the CLAS Collaboration at the Thomas Jefferson
National Accelerator Facility for the reaction of
are reanalyzed within a relativistic meson-exchange model of hadronic
interactions. The present model is an extension of the one developed in an
earlier work by Nakayama, Oh, and Haberzettl [Phys. Rev. C 74, 035205 (2006)].
In particular, the role of the spin-5/2 and -7/2 hyperon resonances, which were
not included in the previous model, is investigated in the present study. It is
shown that the contribution of the hyperon having spin-7/2 and
positive parity has a key role to bring the model predictions into a fair
agreement with the measured data for the invariant mass
distribution.Comment: 8 pages, 3 figures, REVTe
Flat-band excitonic states in Kagome lattice on semiconductor surface
Excitonic properties in the Kagome lattice system, which is produced by
quantum wires on semiconductor surfaces, are investigated by using the exact
diagonalization of a tight binding model. It is shown that due to the existence
of flat bands the binding energy of exciton becomes remarkably large in the
two-dimensional Kagome lattice compared to that in one-dimensional lattice, and
the exciton Bohr radius is quite small as large as a lattice constant. We also
discuss the magnetic field effects on the exciton binding energy and the
stability of exciton against the creation of charged exciton and biexciton.Comment: 5 pages, 5 figure
Superfield Formulation for Non-Relativistic Chern-Simons-Matter Theory
We construct a superfield formulation for non-relativistic
Chern-Simons-Matter theories with manifest dynamical supersymmetry. By
eliminating all the auxiliary fields, we show that the simple action reduces to
the one obtained by taking non-relativistic limit from the relativistic
Chern-Simons-Matter theory proposed in the literature. As a further
application, we give a manifestly supersymmetric derivation of the
non-relativistic ABJM theory.Comment: 18 page
On the sign of the pi-rho-omega coupling constant
It is shown that the relative sign between the and
coupling constants can be determined most sensitively from production
processes in collisions. Recent data on these reactions clearly favor the
sign of the coupling constant which is opposite to that
inferred from studies of the photoproduction reaction in combination with the
vector meson dominance assumption and used by many authors. Implication of this
finding in the description of other reactions is discussed.Comment: 6 pages, 4 figures, REVTeX, to be published in Phys. Lett.
Quantum metrology beyond the classical limit under the effect of dephasing
Quantum sensors have the potential to outperform their classical
counterparts. For classical sensing, the uncertainty of the estimation of the
target fields scales inversely with the square root of the measurement time T.
On the other hand, by using quantum resources, we can reduce this scaling of
the uncertainty with time to 1/T. However, as quantum states are susceptible to
dephasing, it has not been clear whether we can achieve sensitivities with a
scaling of 1/T for a measurement time longer than the coherence time. Here, we
propose a scheme that estimates the amplitude of globally applied fields with
the uncertainty of 1/T for an arbitrary time scale under the effect of
dephasing. We use one-way quantum computing based teleportation between qubits
to prevent any increase in the correlation between the quantum state and its
local environment from building up and have shown that such a teleportation
protocol can suppress the local dephasing while the information from the target
fields keeps growing. Our method has the potential to realize a quantum sensor
with a sensitivity far beyond that of any classical sensor
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