One-gluon exchange effects on linear meson trajectories in the covariant oscillator quark model
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: Possible evidence for a chiral particle D1**chi, axial vector in the D meson system
abstract: In the covariant level-classification scheme of hadrons proposed recently, the existence of "chiral particles", scalar and axial-vector mesons as the partners of the ground-state pseudo-scalar and vector mesons, respectively, were predicted in the D and B meson systems, realizing a linear representation of chiral symmetry. In this work we reanalyze the D* pi mass spectra obtained through the Upsilon (4S) and Z0 decays to show a possibility for the D_1chi.

title: Is the f1(1420) Our First Hybrid Meson

title: Electromagnetic transitions of light-through-heavy mesons and the covariant oscillator 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: Collinear solution to the general relativistic three-body problem
abstract: The three-body problem is reexamined in the framework of general relativity. The Newtonian three-body problem admits Euler's collinear solution, where three bodies move around the common center of mass with the same orbital period and always line up. The solution is unstable. Hence, it is unlikely that such a simple configuration would exist owing to general relativistic forces dependent not only on the masses but also on the velocity of each body. However, we show that the collinear solution remains true with a correction to the spatial separation between masses. Relativistic corrections to the Sun-Jupiter Lagrange points L{sub 1}, L{sub 2}, and L{sub 3} are also evaluated.

title: Moment Approach to Determining the Orbital Elements of an Astrometric Binary with a Low Signal-to-Noise Ratio
abstract: A moment approach to the orbit determination of an astrometric binary with a low signal-to-noise ratio from astrometric observations alone is proposed, especially aiming at a close binary system with a short orbital period, such as Cyg X-1, and also at a star wobbled by planets. As an exact solution to the nonlinearly coupled equation, the orbital elements are written in terms of the second and third moments of projected positions that are measured by astrometry. This may hold the possibility of the true orbit estimate.

title: Possible latitude effects of Chern-Simons gravity on quantum interference
abstract: It has been recently suggested that possible effects of Chern-Simons gravity on a quantum interferometer are dependent on the latitude and direction of the interferometer on Earth in orbital motion around Sun. Continuing work initiated in the earlier publication [Okawara, Yamada and Asada,  (2012)], we perform numerical calculations of time variation in the induced phase shifts for nonequatorial cases. We show that the maximum phase shift at any latitude might occur at 6, 0 (and 12), and 18 hours (in local time) of each day, when the normal vector to the interferometer is vertical, eastbound and northbound, respectively. If two identical interferometers were located at different latitudes, the difference between two phase shifts that are measured at the same local time would be $O(\sin \delta\varphi)$ for a small latitude difference $\delta\varphi$. It might thus become maximally $\sim 20$ percents for $\delta\varphi \sim 10$ degrees, for instance.