A new quark model for hadrons

It is suggested that quarks and leptons are composites of still more fundamental PRE-entities.     

A kinematical model for quarks and hadrons

Starting from simple topological arguments due to Dirac on the classical rotational properties of extended rigid bodies, we abstract the concept of a finite-size spinor (FSS). The FSS is a concept distinct from both point spinors (e.g., electrons) and composite spinors (e.g., nuclei), and suggests a new model for baryons. The FSS offers a natural explanation of threeness for the quarks, excludes the existence of free quarks, denies the operational definition of quark spin statistics, and, moreover, leads to the dual model of hadronic interactions.Research supported in part by the National Science Foundation, the Army Research Office (Durham), and the U.S. Atomic Energy Commission.     

A Markoffian master equation for high-field electron transport

The high-field electron transport problem is reanalyzed in the frame of a Markoffian (i.e. memoryless) master equation proposed by Hashitsume et al. for the reduced density matrix. It is shown that a Markoffian high-field transport equation for the velocity distribution can be established, which considerably simplifies the usual (non-Markoffian) approaches of hot electron transport.     

A non-Abelian vortex-bond model of hadrons

It is argued for a general class of models by analyzing the internal holonomy group of the cylindrically symmetric solutions that the most general vortex-like configurations of minimal energy can always be transformed to Abelian form. The corresponding “magnetic” fluxes are defined gauge invariantly. In the case of the SU(3) local gauge group, Nambu's valency-model is recovered. The stability problem in the case of small-amplitude oscillations reduces to the analogue investigation for “truly” Abelian vortices.     

A constituent quark model for particle production in collisions between hadrons

It is shown that a constituent picture of hadrons, with no other fundamental assumption than that only one constituent in each hadron interacts with one constituent in the other hadron, explains several features of particle production in high-energy collisions. We obtain KNO scaling of the particle multiplicity, a neutral for multiplicity for fixed charged multiplicity which is independent of the energy, and a rapidity distribution of the central fireball which depends on n/〈n〉 only. Numerical applications show that the quark momentum distribution which reproduces the experimental data in strong interactions is very similar to the valence quark momentum distribution derived from deep inelastic scattering experiments.     

The case for a quartet model of hadrons

A model of hadrons based on an underlying quartet leads to a more satisfactory picture of weak interactions than one based on a triplet. Hadrons containing the fourth type of quark may be as low as 700 MeV above their uncharmed counterparts. It is argued that charmed hadrons should be searched for in photoproduction and (under certain circumstances) in hadronic formation experiments.     

Jet-structure and the statistical model for electron-positron annihilation into hadrons

We consider a statistical model for electron-positron annihilation into hadrons, whose input single particle distribution function $\text{?(p)}$ is power behaved for large values of the momentum $\text{p, ?(p) ～ p}{}^{\mathrm{m?2}}$. Three classes can be distinguished, corresponding to m > 0, m = 0 and m < 0. The first two classes have asymptotically a spherically symmetric event structure, while for the case m < 0 we argue that energy-momentum conservation forces the events to be jet-like.     

Bag model of hadrons with massive quarks

We generalize the bag model of hadrons to include massive quarks and investigate in particular the properties of the l = 0 octet and decimet baryons with m_p = m_n = 0, m_λ = 270 MeV (obtained by fitting the decimet). The magnetic moments and weak axial vector/vector transition moments are calculated and compared with experimental data for cases in which data exists. We also speculate on the mechanism by which the remaining degeneracies in the baryons are lifted and on modifications which are necessary to construct a bag model of mesons.     

Hydrodynamical model of electron-positron annihilation into hadrons

Landau's hydrodynamical model of multiparticle production is formulated for e⁺e^? → hadrons at center-of-momentum energies 10 GeV and higher. An analytical solution to the problem of spherical expansion of a relativistic fluid is presented. When hadrons condense out at the last stage of expansion, fluid thermal motion is taken into account. We derive predictions for multiplicities, average secondary energies and inclusive single particle distributions for various secondary hadrons; these results are then compared to other models. Finally, we investigate the internal consistency of the model.     

QCD and a holographic model of hadrons

We propose a five-dimensional framework for modeling low-energy properties of QCD. In the simplest three parameter model we compute masses, decay rates and couplings of the lightest mesons. The model fits experimental data to within 10%. The framework is a holographic version of the QCD sum rules, motivated by the anti-de Sitter/conformal field theory correspondence. The model naturally incorporates properties of QCD dictated by chiral symmetry, which we demonstrate by deriving the Gell-Mann-Oakes-Renner relationship for the pion mass.     

Black sphere model for the absorption of negative hadrons by nuclei

The slowing down of hadrons in a moderator entails an intensity loss by nuclear absorption. The loss is expected to be particularly large for negative hadrons, due to a combination of Coulomb attraction and strong local absorption. A black sphere absorption model is set up and used for numerical calculations of absorption probability per momentum loss. ForK ^? and¯p on heavy nuclei, a sharp maximum is found for kinetic energies below 0.1 MeV.     

Detailed balance in open quantum Markoffian systems

Agarwal's definition of detailed balance for open quantum Markoffian systems is shown to arise from microreversibility in an analogous fashion to the familiar classical concept. It is therefore presented as the appropriate formal generalisation of the classical result to the quantum-mechanical regime. This fully quantum-mechanical approach is discussed in relation to the Fokker-Planck equations of the phase-space calculus and the Pauli master equation; two contexts in which a pseudo-classical form of detailed balance is well known. Our discussion is illustrated through the examples of the damped harmonic oscillator and the single mode laser.Supported by a New Zealand U.G.C. Post Graduate Scholarship.     

Gluon condensation and the bag model of hadrons

Migdal's scheme for gluon condensation is applied to a model where gluons are dynamically confined by coloured Higgs fields and are also subjected to ac-number colour field due to external “semiclassical” quarks. We show that, no matter how strong the external field becomes, stabilization of the gluonic ground state is guaranteed by the formation of an inhomogeneous gluon condensate. The contribution to the total energy from the condensate is computed semiclassically using a variational approximation. A physical interpretation of the results obtained is given in terms of a renormalization of the MIT bag model input parameters in particular the zero point energy coefficientZ and the bag constantB.

     

Recent heavy ion experiments and statistical model of hadrons

The combined CERN and Brookhaven heavy ion (H.I.) data supports a scenario of hadron gas which is in chemical and thermal equilibrium at a temperatureT of about 140 MeV. Using the Brown-Stachel-Welke model (which gives 150 MeV) we show that in this scenario, the hot nucleons have mass 3T and the and mesons have masses close to T and 2T, respectively. A simple model with pions and quarks supports the co-existence of two phases in these heavy ion experiments, suggesting a second order phase transition. The masses of the pion, rho and the nucleon are intriguingly close to the lattice screening masses.Supported by FAPESP of São Paulo, Brasil and DST grant no SP/S2/K04/92 Govt. of India