Martina M. Brisudova

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. (c) 2000 The American Physical Society.

Initial studies of bound states in light-front QCD.

We present the first numerical QCD bound state calculation based on a renormalization group-improved light-front Hamiltonian formalism. The QCD Hamiltonian is determined to second order in the coupling, and it includes two-body confining interactions. We make a momentum expansion, obtaining an equal-time-like Schr˝ odinger equation. This is solved for quark-antiquark constituent states, and we obtain a set of self-consistent parameters by fitting B meson spectra.

Quarkonia in Hamiltonian light front QCD

A constituent parton picture of hadrons with logarithmic confinement naturally arises in weak coupling light-front QCD. Confinement provides a mass gap that allows the constituent picture to emerge. The effective renormalized Hamiltonian is computed to O(g{sup 2}), and used to study charmonium and bottomonium. Radial and angular excitations can be used to fix the coupling {alpha}, the quark mass M, and the cutoff {Lambda}. The resultant hyperfine structure is very close to experiment. {copyright} {ital 1997} {ital The American Physical Society}

New Glueball-Meson Mass Relations

Using the “glueball dominance” picture of the mixing between q¯ q mesons of different hidden flavors, we establish new glueball-meson mass relations which serve as a basis for glueball spectral systematics. For the tensor glueball mass 2.3 ± 0.1 GeV used as an input parameter, these relations predict the following glueball masses: M(0 ++ ) ≃ 1.65 ± 0.05 GeV, M(1 ) ≃ 3.2 ± 0.2 GeV, M(2 + ) ≃ 2.95 ± 0.15 GeV, M(3 ) ≃ 2.8 ± 0.15 GeV. We briefly discuss the failure of such relations for the pseudoscalar sector. Our results are consistent with (quasi)-linear Regge trajectories for glueballs with slope ≃ 0.3 ± 0.1 GeV 2 .

Effect of color screening on heavy quarkonia Regge trajectories

Abstract Using an unquenched lattice potential to calculate the spectrum of a bottomonium-like system, we demonstrate numerically that the effect of pair creation is to produce termination of the real part of hadronic Regge trajectories, in contrast to the Veneziano model and the vast majority of phenomenological generalizations. Termination of the real part of Regge trajectories may have significant experimental consequences.

JAYNES-CUMMINGS MODEL WITH DISPLACED NUMBER STATES

We investigate the dynamics of the Jaynes-Cummings model with the cavity field initially prepared in the displaced number state. The time evolution of the atomic population inversion, squeezing of the cavity field and the emission spectra from the two-level atom are studied.

The spin and flavour dependence of high-energy photoabsorption

Abstract: We analyse the low x, low Q2 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.

An attempt to do without dark matter.

Abstract: The discrepancy between dynamical mass measures of objects such as galaxies and the observed distribution of luminous matter in the universe is typically explained by invoking an unseen “dark matter” component. Dark matter must necessarily be nonbaryonic. We introduce a simple hypothesis to do away with the necessity for dark matter by introducing an additional nongravitational force coupled to baryon number as a charge. We compare this hypothesis to Milgroms modified Newtonian dynamics. The model ultimately fails when confronted with observation, but it fails in an interesting way.

Nonlinear Dissipative Oscillator with Displaced Number States

Abstract We study the interaction of a Kerr-like medium with light initially prepared in a displaced number state. We analyse squeezing properties and photon statistics at the output of a Kerr-like medium. We show that under certain conditions the superposition of two displaced number states can be created. We study the influence of dissipation on the formation of the superposition state.

Cosmology With a Long-Range Repulsive Force

We discuss the properties of a cosmology dominated by a charged scalar field with a repulsive, long-range self-interaction. The interaction, in the form of a vector field with a tiny mass, can have a dramatic effect on the evolution of the universe, with interesting consequences — including in some cases accelerated expansion. One characteristic of the model is an oscillating deceleration parameter, which would potentially allow it to be distinguished from other scalar field models such as quintessence.