Radiative Decays of Ground-State Mesons in the Covariant Quark Model

title: Meson spectra and wave functions in a covariant version of the linear-plus-Coulomb potential quark model
abstract: We examine mass spectra and wave functions of nn, cc and bb meson systems in the covariant oscillator quark model with the four-dimensional color-Coulomb interaction and find that these spectra are described well. Our results seem to suggest that the present model may be considered effectively as a covariant version of the nonrelativistic linear-plus-Coulomb potential quark model.

title: HYBRID MESONS AND DOUBLING OF THE FOUR FLAVOR NONETS WITH J(PC) = (0,1,2)++ AND 1+-: THREE RELATED TALKS PRESENTED AT HADRON '89

title: One-gluon exchange effects on linear meson trajectories in the covariant oscillator quark model
abstract: SummaryWe investigate one-gluon exchange effects on the linear Regge trajectories of all quark-antiquark meson systems, from light through heavy quarks, in the framework of the covariant oscillator quark model. This model gives linearly rising trajectories to both orbitally and radially excited states in the limit of neglecting perturbative QCD effects. We find that the spin-independent one-gluon exchange interaction barely affects the orbital excitations, preserving the well-known linearity of the leading Regge trajectories, but for the radial excitations it makes an appropriate contribution, in conformity with the observed behaviour largely deviating from the linear trajectories. We also calculate the hyperfine mass splittings of all ground-stateS-wave mesons. For as yet unknown mass splittings, we findM(B*c)−M(Bc)≈50 MeV andM(Y)−M(ηb)≈49 MeV.

title: A Universal Spring and Baryon Regge Trajectories
abstract: In the covariant oscillator quark model (COQM) the squared-mass spectra of cvnfined meson and baryon systems are described by harmonic oscillators. In this work we propose a hypothesis of universal spring in COQM, which predicts the respective values of oscillator quanta in terms of constituent quark masses and a spring constant. In the previous work we have examined the universality within the meson system. In this work we shall examine the universality, further, in the baryon system by comparing the predicted orbital Regge trajectories in the respective flavor channels with experiments. The spring constants in the meson and baryon systems are related mutually by a color factor obtained through heuristic arguments. It seems to us that our universality is realized experimentally for the light-quark baryons, while for the heavy-flavored baryons the experimental knowledge is too poor to lead to any definite conclusions.

title: Electromagnetic transitions of light-through-heavy mesons and the covariant oscillator quark model

title: Triangular solution to the general relativistic three-body problem for general masses
abstract: Continuing work initiated in an earlier publication [Ichita, Yamada and Asada,  (2011)], we reexamine the post-Newtonian effects on Lagrange's equilateral triangular solution for the three-body problem. For three finite masses, it is found that a triangular configuration satisfies the post-Newtonian equation of motion in general relativity, if and only if it has the relativistic corrections to each side length. This post-Newtonian configuration for three finite masses is not always equilateral and it recovers previous results for the restricted three-body problem when one mass goes to zero. For the same masses and angular velocity, the post-Newtonian triangular configuration is always smaller than the Newtonian one.

title: Post-Newtonian effects of planetary gravity on the perihelion shift
abstract: We consider a coplanar system comprising of a massive central body (a star), a less massive secondary (a planet) on a circular orbit, and a test particle on a bound orbit exterior to that of the secondary. The gravitational pull exerted on the test particle by the secondary acts as a small perturbation, wherefore the trajectory of the particle can be described as an ellipse of a precessing perihelion. While the apsidal motion is defined overwhelmingly by the Newtonian portion of the secondary’s gravity, the post-Newtonian portion, too, brings its tiny input. We explore whether this input may be of any astrophysical relevance in the next few decades. We demonstrate that the overall post-Newtonian input of the secondary’s gravity can be split into two parts. One can be expressed via the orbital angular momentum of the secondary and another via its orbital radius. Despite some moderately large numerical factors showing up in the expressions for these two parts, the resulting post-Newtonian contributions from the secondary’s gravity into the apsidal motion of the test particle turn out to be small enough to be neglected in the near-future measurements.

title: Possible daily and seasonal variations in quantum interference induced by Chern-Simons gravity.
abstract: Possible effects of Chern-Simons (CS) gravity on a quantum interferometer turn out to be dependent on the latitude and direction of the interferometer on Earth in orbital motion around the Sun. Daily and seasonal variations in phase shifts are predicted with an estimate of the size of the effects, wherefore neutron interferometry with ~5 m arm length and ~10(-4) phase measurement accuracy would place a bound on a CS parameter comparable to the Gravity Probe B satellite.

title: Marginally stable circular orbit of a test body in spherically symmetric and static spacetimes
abstract: We study a marginally stable circular orbit (MSCO) such as the innermost stable circular orbit (ISCO) of a timelike geodesic in any spherically symmetric and static spacetime. It turns out that the metric components are separable from the constants of motion along geodesics. We show also that a metric component $g_{rr}$ with a radial coordinate $r$ does not affect MSCOs. This suggests that, as a test of gravity, any ISCO measurement may be put into the same category as gravitational redshift experiments. MSCOs for exact solutions to the Einstein's equation are also mentioned.

title: Possible altitudinal, latitudinal, and directional dependence of the relativistic Sagnac effect in Chern-Simons modified gravity
abstract: Toward a test of parity violation in a gravity theory, possible effects of Chern-Simons (CS) gravity on an interferometer have been recently discussed. Continuing work initiated in an earlier publication [Okawara, Yamada and Asada,  (2012)], we study possible altitudinal and directional dependence of relativistic Sagnac effect in CS modified gravity. We compare the CS effects on Sagnac interferometers with the general relativistic Lense-Thirring (LT) effects. Numerical calculations show that the eastbound Sagnac interferometer might be preferred for testing CS separately, because LT effects on this interferometer cancel out. The size of the phase shift induced in the CS model might have an oscillatory dependence also on the altitude of the interferometer through the CS mass parameter $m_{CS}$. Therefore, the international space station site as well as a ground-based experiment is also discussed.