G. Preparata

On the stability of the perturbative ground state in non-abelian Yang-Mills theories

Abstract We study the stability properties of the perturbative ground state of non-abelian Yang-Mills theories, by analyzing the energy density of a class of gauge-invariant wave functionals which include the perturbative ground state. We find a minimum at a value of the “gluon condensate” (gH ∗ ) 2 whicch does not scale according to asymptotic freedom expectations. The consequences of our results for the reliability of perturbation theory at short distances are briefly discussed.

Current Particle Matrix Elements in Acd

Abstract Using anisotropic chromo-dynamics (ACD) we compute the relevant one-particle matrix elements of the electroweak currents. Good agreement with experiments is found for light mesons, while some discrepancies for heavy mesons (ϒ, ϒ′) are well understood within the limitations of our approximations.

A realistic model of the semileptonic decays of beauty

Abstract A realistic calculation of the semileptonic decays of B-mesons, which depends in an essential manner on the Kobayashi-Maskawa matrix elements Vb→c and Vb→u only, is presented. A very good fit to the experimental lepton spectrum is obtained for | V b→u V b→c | 2 = 0.10 ± 0.06 , and from the world average for the B-lifetime (τB = 1.04 ± 0.15 ps), Vb→c = (5.9 ± 0.4) × 10−2 and Vb→u = (1.9 ± 0.5) × 10−2 are derived.

Do we understand parity violation in nucleon-nucleon interactions?

Abstract We apply the wavefunction (WF) weak renormalization effect to parity violation in nuclei and proton-nucleon scattering at low and intermediate energies. We find that, while at high and intermediate energies the WF mechanism is expected to give the largest contribution, at low energies it must compete with other sources of parity violations.

Chirality and its breaking in a new theory of hadrons

Abstract We show that in Anisotropic Chromo-Dynamics (ACD), a new approach to the dynamics of coloured, confined quarks, the π -meson is a qq-bound state very close to the Nambu-Goldstone boson of a spontaneously broken chiral symmetry. We calculate the “current” quark masses and obtain m u (0) ≈ m d (0) ≈ 18 MeV , and m s (0) ≈ 123 Mev , in disagreement with the usual “strong PCAC” Ansatz.

Geometrodynamics for quarks and hadrons: The baryon states

Abstract In the geometrodynamical approach, baryons turn out to exist only in configuration where the quark coordinates are spatially aligned. As a consequence, the spectrum of [SU(6), L P ] multiplets follows the pattern: (56, 0 + ), (70, 1 − ; (56, 2 + ), (70, 2 + ); (70, 3 − );… with their radial recurrences. This appears to solve an old quark-model puzzle.

Does asymptotic freedom shine on the lattice

Abstract Motivated by the recent discovery of the violation of asymptotic freedom (AF) in continuum Yang-Mills theories, we have looked for similar phenomena in lattice gauge theories (LGT). We have found indications that AF is violated also in LGTs, and that its violation is just of the type found in continuum theories.

Multisequence comparisons in protein coding genes: Search for functional constraints

A very powerful method for detecting functional constraints operative in biological macromolecules is presented. This method entails performing a base permanence analysis of protein coding genes at each codon position simultaneously in different species. It calculates the degree of permanence of subregions of the gene by dividing it into segments,c codons long, counting how many sites remain unchanged in each segment among all species compared. By comparing the base permanence among several sequences with the expectations based on a stochastic evolutionary process, gene regions showing different degrees of conservation can be selected. This means that wherever the permanence deviates significantly from the expected value generated by the simulation, the corresponding regions are considered “constrained” or “hypervariable”.The constrained regions are of two types: α and β. The α regions result from constraints at the amino acid level, whereas the β regions are those probably involved in “control” processing. The method has been applied to mitochondrial genes coding for subunit 6 of the ATPase and subunit 1 of the cytochrome oxidase in four mammalian species: human, rat, mouse, and cow. In the two mitochondrial genes a few regions that are highly conserved in all codon positions have been identified. Among these regions a sequence, common to both genes, that is complementary to a strongly conserved region of 12S rRNA has been found. This method can also be of great help in studying molecular evolution mechanisms.

Parity non-conservation in low energy nucleon-nucleon interaction

Abstract We apply a recently proposed theory of parity violation effects in the wave function of nucleons to the derivation of the parity violating (PV) nucleon-nucleon potential. We obtain PV terms in the hamiltonian much larger than previously calculated. A successful application of such potential is made to the calculation of the proton asymmetry at low energies.

A MONTE CARLO PROGRAM FOR GENERATING HADRONIC FINAL STATES IN ELECTRON POSITRON ANNIHILATIONS

Titleofprogram: EPOS particlesin thefinal state(30 or 40particlesarenot uncommon at W= 35 GeV) [1]. Thecomplexityof this phenomenonneeds Cataloguenumber:ACDM a theoreticalframework for describingand understandingthe basicphysicalmechanisminvolved. Programobtainablefrom: CPC ProgramLibrary, Queen’sUniThe presentprogramis aneventgeneratorof hadronicfinal versityof Belfast,N. Ireland(seeapplicationform in thisissue) statesbasedon the Fire-String theory and hasbeen shownto reproducevery well all thefeaturesexperimentallyobserved[2]. Computers on which the program is operable: CDC 7600/CYBER875/VAX 780 Methodofsolution The program is based on the Monte Carlo method and its Operatingsystem:7000 SCOPE2.1.4 (CDC)/NOS-BELevel generateseventswith weight= I using the Fire-String theory 587/VAX-VMS [2]. The notion of Fire-String comesfrom the descriptionof hadronicmatterin termsof boundstates(bags)of quarksand Programminglanguage:FORTRAN antiquarksin the theoretical framework named Quark-Geometro-Dynamics[3]. In this approachto the dynamicsof high High speedstoragerequired: 50 Kwords on CDC’s anda peak energyphysicsonecandefinea highly excitedquark—antiquark valueof 240 Kwords on theVAX boundstatewith a cylindricalstructure,calledFire-string(FS). Theevolutionof theFSandits decaymodesareresponsiblefor No. of bits in a word: 60 (CDC), 32 (VAX) thedepositionof hadronsin thefinal states. All these physical ideas have been implementedin the No. of lines in combinedprogram and testdeck: 3938 presentprogram.