Effect of Color Screening on Heavy Quarkonia Regge Trajectories

Using an unquenched lattice potential to calculate the spectrum of the bottomonium system, we demonstrate numerically that the effect of pair creation is to produce termination of hadronic Regge trajectories, in contrast to the Veneziano model and the vast majority of phenomenological generalizations. Termination of Regge trajectories may have significant experimental consequences.Comment: 8 pages, 3 figures, published version including a discussion of coupling to open channel

Heavy Meson Description with a Screened Potential

We perform a quark model calculation of the $b\bar{b}$ and $c\bar{c}$ spectra from a screened funnel potential form suggested by unquenched lattice calculations. A connection between the lattice screening parameter and an effective gluon mass directly derived from QCD is established. Spin-spin energy splittings, leptonic widths and radiative decays are also examined providing a test for the description of the states.Comment: 17 pages, no figures, to appear in Phys. Rev.

Effective Functional Form of Regge Trajectories

We present theoretical arguments and strong phenomenological evidence that hadronic Regge trajectories are essentially nonlinear and can be well approximated, for phenomenological purposes, by a specific square-root form.Comment: 29 pages, LaTeX. Published versio

The spin and flavour dependence of high-energy photoabsorption

We analyse the low $x$, low $Q^2$ polarised photoabsorption data from SLAC and use this data to make a first estimate of the high-energy part of the Drell-Hearn-Gerasimov sum-rule. The present status of spin dependent Regge theory is discussed