Showing papers in "Nuovo Cimento Della Societa Italiana Di Fisica A-nuclei Particles and Fields in 1984"
TL;DR: In this paper, a mathematical formulation for a gauge theory for fields in the adjoint representation of SUn, where the fields are general differential forms living on the lattice objects, like sites, links, plaquettes, etc.
Abstract: We present a mathematical formulation for a gauge theory for fields in the adjoint representation ofSUn, where the fields are general differential forms living on the lattice objects, like sites, links, plaquettes, etc. By a general definition of covariant derivatives we write down the Lagrangian and Hamiltonian densities for the gauge field. Imposing the unitary condition for the gauge link variable we can obtain the well-known Wilson action and for time continuous the Kogut-Susskind Hamiltonian formalism. Furthermore, we present the gauge formulation for scalar and pseudoscalar fields.
44 citations
TL;DR: In this paper, the authors use perturbative QCD in conjunction with Mandelstam's path dependence formalism to evaluate explicit expressions for the quark two-point Green's function in momentum space.
Abstract: We use perturbative QCD in conjunction with Mandelstam’s path dependence formalism to evaluate explicit expressions for the quark two-point Green’s function in momentum space. In doing this we discuss in detail the mechanism of gauge invariance restoration and the regularization of path divergences. We calculate the renormalization constants of the colour connector and the quark connector hybrid and show that they satisfy the Slavnov-Taylor identities. Our results coincide at least toO(αs) with those obtained previously by other authors within thez-field formalism. We interpret this agreement as a justification of the basic identity underlying thez-field algorithm.
44 citations
TL;DR: In this paper, it has been shown that information on the effective yields of different elements in the annihilation process may impose limits on the possible amount of antimatter in the early universe and other important cosmological parameters.
Abstract: It has been shown that information on\(\bar p^4 He\) annihilation may impose limits on the possible amount of antimatter in the early Universe and other important cosmological parameters. We discuss which channels of\(\bar p^4 He\) annihilation must be measured and what restrictions on the parameters of GUT and SUSY models may be obtained from knowledge of the effective yields of different elements in\(\bar p^4 He\) annihilation.
42 citations
CERN1
TL;DR: In this article, the γ-rays from the decay η′η→4γ were detected with the hodoscope spectrometer GAMS-2000 and the measured ratio of the partial widths of the G→η−n and the G → ηη decay channels is 2.7±0.8 in agreement with the value expected for glueballs.
Abstract: η′η pair production in the charge exchange reaction π−p→η′ηn has been observed and studied in a search for glueballs with the 38 GeV/c pion beam of the 70 GeV IHEP accelerator. The γ-rays from the decay η′η→4γ were detected with the hodoscope spectrometer GAMS-2000. The η′η events in the mass range from threshold up to 1.8 GeV are decays of the scalar G(1590)-meson which has been already observed in its ηη decay mode. The measured ratio of the partial widths of the G→η′η and the G → ηη decay channels is 2.7±0.8 in agreement with the value expected for glueballs.
42 citations
TL;DR: In this article, a pedagogical introduction to supersymmetric quantum mechanics with emphasis on the question of spontaneous supersymmetry breaking is given, and various models both with N = 1 and N = 2 supersymmety are presented and analysed.
Abstract: We give a pedagogical introduction to supersymmetric quantum mechanics with emphasis on the question of spontaneous supersymmetry breaking. Various models both withN=1 andN=2 supersymmetry are then presented and analysed.
34 citations
TL;DR: The self-adjointness of the Aharonov-Bohm Hamiltonian has been shown to allow a continuous family of different dynamics including those following from Pauli's criterion of rotational invariance and single valuedness as discussed by the authors.
Abstract: Self-adjointness of the time-independent Aharonov-Bohm Hamiltonian is shown to allow a continuous family of different dynamics including those following from Pauli's criterion of rotational invariance, Aharonov-Bohm criterion of single valuedness and a version of Pauli's criterion appropriate to cylindrical symmetry suggested by Henneberger. A time-dependent fluxF(t) linking the Aharonov-Bohm solenoid leads to the time-dependent AB Hamiltonian. Explicit solutions in cases with and without inaccessible regions for the charged particle rule out applicability of both versions of the Pauli criterion. The solutions contain one time-independent parameter α, integer values of which correspond to single-valued wave functions. Any real (integer or noninteger) value of α is allowed. Charge and current densities depend on α andF(t) only through the combination α−eF(t)/2π and lead to the conclusion that physical effects of changing the flux during an experiment can be understood as local effects of the electric field inevitably associated with changing magnetic flux.
27 citations
TL;DR: When two nuclei form a nuclear molecule by touching each other only in their surface zones, a new collective model appeared as mentioned in this paper, which can be described as butterfly-and belly-dancer-type motions.
Abstract: When two nuclei form a nuclear molecule by touching each other only in their surface zones, new collective model appear. These modes can be described as butterfly- and belly-dancer-type motions, but also β- and γ-vibrational degrees of freedom of the individual nuclei are included. The appropriate collective variables are introduced. The coordinate symmetries arising from the definition of the internal system are discussed. As an example the classical Hamilton function for the pole-pole orientation is constructed. After quantizing, the Hamiltonian is obtained. The model is applied to238U-238U where such configurations seem to be good candidates for understanding the structures observed in positron experiments.
22 citations
TL;DR: In this paper, the energy spectrum and angular distribution of atmospheric prompt muons are calculated by using an integral solution for production of charmed particles, their decay and muon transport in the atmosphere.
Abstract: The energy spectrum and angular distribution of atmospheric prompt muons are calculated by using an integral solution for production of charmed particles, their decay and muon transport in the atmosphere. Current experimental information from accelerator and theoretical ideas about charm cross-section and semi-leptonic decay are used to give a reference prompt muon spectrum to compare with that from conventional sources (π and K decay). The obtained differential spectrum has an energy dependence which approaches that of the primary cosmic rays. The integral intensity of prompt muons is equal to the conventional one at about 250 TeV. The angular distribution is found to be practically flat in the range (0÷80)0 irrespective of the muon energy. On the basis of this analysis we estimate that accurate measurements of muon energy spectrum and angular distribution at energies greater than 10 TeV should allow one to obtain useful information regarding charm hadroproduction cross-section in the 100 TeV region.
22 citations
TL;DR: In this article, it was shown that 1±+ resonances can be observed at an appreciable rate in tagged e+e− experiments at low q 2 in low-q 2.
Abstract: We show that 1±+ resonances can be observed at an appreciable rate in tagged e+e− experiments at lowq2. We discuss the\(\left( {q\overline q } \right), \left( {qq\overline q \overline q } \right), \left( {q\overline q g} \right), \) (gg) and (ggg) spectroscopy and compute the corresponding γγ partial widths.
18 citations
TL;DR: The use of the correct variables in (pp), (e+e−), and deep-inelastic scattering (DIS) processes allows universality features to be established in these different ways of producing multihadronic states as mentioned in this paper.
Abstract: The use of the correct variables in (pp), (e+e−), and deep-inelastic scattering (DIS) processes allows universality features to be established in these—so far considered—different ways of producing multihadronic states.
16 citations
TL;DR: In this article, the authors proved that any free Dirac wave packet with positive energy is spread over all of R3 and discussed the fact that this is the case for any Dirac packet with negative energy.
Abstract: We prove and discuss the fact that any free Dirac wave packet with positive energy is spread over all ofR3.
TL;DR: The spin-1/2 Dirac singleton and the neutrino can have a gauge freedom similar to the gauge freedom of the electromagnetic-field potentials as mentioned in this paper, and an indefinite-metric field quantization for these field is performed.
Abstract: The spin-1/2 Dirac singleton Di and the neutrino can have a gauge freedom similar to the gauge freedom of the electromagnetic-field potentials. An indefinite-metric field quantization for these field is performed.
TL;DR: On montre que les signes oppose des lagrangiens libres A and B sont necessaires quand les champs se melangent hyperboliquement; qu'un lagrangien libre invariant de jauge for un triplet SU 1,1 de champs peut se definir avec des contributions de signe uniforme for les 3 champs as discussed by the authors.
Abstract: On montre que les signes opposes des lagrangiens libres A et B sont necessaires quand les champs se melangent hyperboliquement; qu'un lagrangien libre invariant de jauge pour un triplet SU 1,1 de champs peut se definir avec des contributions de signe uniforme pour les 3 champs; que des lagrangiens libres de signe soit positif soit negatif donnent des energies cinetiques positives dans une theorie quantifiee
TL;DR: In this paper, the non-leptonic decay rates of Λc+→Λπ+ were calculated by using current algebra and an evaluation of the matrix element by using nonrelativistic SU6 wave functions.
Abstract: The nonleptonic decay rates\(\Lambda _c^ + \to p\bar K^0 \) and Λc+→Λπ+ are calculated by using current algebra and an evaluation of the matrix element by using nonrelativisticSU6 wave functions. The results are found to be in good agreement with experiment. The results are also compared with earlier quark model and MIT bag model calculations.
TL;DR: In this article, two Higgs fields are introduced which break the SO4,2 symmetry spontaneously into SO3,2 and SO3⊗SO2 symmetry, respectively.
Abstract: ASO4,2 conformally symmetric model is presented for strong interactions at low energies. In order to obtain a realistic description of interacting gluons and quarks, two Higgs fields are introduced which break theSO4,2 symmetry spontaneously intoSO3,2 andSO3⊗SO2 symmetry, respectively. We obtain an alternative flat metric, invariant under rotations and translations which leave a preferred time-like geodesic invariant. In terms of this metric quarks and gluons carry out harmonic oscillations with universal frequency ν=(2πR)−1 within a spherical cavity of radiusR. This leads to a hadron spectrum with universal level spacinghν, which is in agreement with our earlier observations.
TL;DR: Born's quantum metric operator and Yukawa's equation are used in the context of a recently proposed framework for quantum space-time to arrive at mass formulae for integral as well as half-integer spin exciton states.
Abstract: Born’s quantum metric operator and Yukawa’s equation are used in the context of a recently proposed framework for quantum space-time to arrive at mass formulae for integral as well as half-integer spin exciton states. A recently performed harmonic analysis of phase-space representations of the Poincare group supplies then the corresponding exciton propagators.
TL;DR: In this article, a spin particuliere des interactions electrofortes des particules de la premiere generation is presented, based on a theoryie de jauge non abelienne.
Abstract: On presente une theorie de jauge non abelienne a spin particuliere des interactions electrofortes des particules de la premiere generation
TL;DR: In this article, the finite-energy sum rules are used for the estimate of the SU3 symmetry-breaking parameter γ = 0.43±0.12. But γ is not a constant.
Abstract: The finite-energy sum rules are used for the estimate of theSU3 symmetry-breaking parameterγ=1-〈s-s〉/〈u-u〉. We obtainγ=0.43±0.12.
TL;DR: In this paper, a spin gauge theory for the massless Dirac electron and Pauli neutrino is presented, based on a particular representation of an eight-dimensional Clifford algebra, which is then transformed by an inner automorphism into the theory describing "up" and "down" dion spinors corresponding to electric charges ± 1/3e and ± 2/3 e.
Abstract: In a previous paper, we introduced the concept of a spin gauge theory. Here we present a specific non-Abelian spin gauge theory of the electrostrong interactions of the particles of the first generation. The theory for the massless Dirac electron and Pauli neutrino is based upon a particular (16×16) representation of an eight-dimensional Clifford algebra, which is then transformed by an inner automorphism into the theory describing «up» and «down» dion spinors corresponding to electric charges ±1/3e and ±2/3e. The transformation of the dion Lagrangian to three other representations of the algebra produces dion spinors of three «colours». Three generators of the gauge transformation form aSU1,1 group, defining a neutral-vector-potential interaction and two unusual interactions with pseudovector potentials, corresponding to bosons with charges ±1/3e. The other generators define neutral vector potentials which mix with that generated fromSU1,1 to give the electromagnetic potential and a «strong» neutral potential. Finally we discuss the results obtained, problems which remain to be solved, and the aims of further work.
TL;DR: In this paper, the magnitude and angular variation of the coherent-scattering amplitude and its dependence on the mass and spin of the incident neutrinos are examined, and for the latter the standard nonrelativistic relation between reflection coefficient and refractive index is re-examined and extended to cover both relativistic and targets of spatially varying density.
Abstract: Coherent detection techniques are being studied both for relativistic neutrinos (e.g. MeV-range solar, ormυ < 10−4 eV «relic» neutrinos) and for nonrelativistic neutrinos (e.g. 1 eV
TL;DR: In this paper, the optical model is illustrated and discussed, in view of accurate phenomenological analyses of experimental data and of the fundamental analyses, based on the nucleon-nucleon interaction in nuclear matter, that have been carried out in the past years.
Abstract: Recent work on the optical model is illustrated and discussed, in view of the accurate phenomenological analyses of experimental data and of the fundamental analyses, based on the nucleon-nucleon interaction in nuclear matter, that have been carried out in the past years. Attention is restricted to the nucleon-nucleus potential, although many of the new results have implications for light- and heavy-ion potential as well
TL;DR: In this paper, a general scheme for deriving the equations of motion for classical particles in the presence of given external fields is presented for the case of a massive chargeless particle whose spin interacts with the curvature and torsion of a gravitational field.
Abstract: A general scheme as been presented for deriving the equations of motion for classical particles in the presence of given external fields. In this paper we illustrate the method for the case of a massive chargeless particle whose spin interacts with the curvature and torsion of a gravitational field. We solve these equations for the case of a constant vector torsion.
TL;DR: In this paper, the large-N limit for a class of matrix models in zero-dimensional space-time is found in closed form for planar graphs in every dimension and a method to sum in an approximate way is proposed and tested in dimension one.
Abstract: The large-N limit is found in closed form for a class of matrix models in a zero-dimensional space-time. A method to sum in an approximate way planar graphs in every dimension is proposed and tested in dimension one.
TL;DR: The elastic angular distribution for the reaction16O+28Si is calculated for the bombarding energiesEc.m.=21.1 MeV and 22.7 MeV by making use of microscopic form factors as mentioned in this paper.
Abstract: The elastic angular distribution for the reaction16O+28Si is calculated for the bombarding energiesEc.m.=21.1 MeV and 22.7 MeV. The imaginary part of the ion-ion potential due to transfer reactions is calculated by making use of microscopic form factors. The depopulation of the entrance channel due to Coulomb excitation and inelastic processes is treated within the coupled-channel framework. By making use of a standard folding expression for the real part of the ion-ion potential the main features of the backward rise of the angular distribution are reproduced. Detailed agreement is obtained by introducing a very-short-range absorption and adjusting slightly the strength of the real potential.
TL;DR: In this paper, a dynamical mechanism for SU3 and SU2 symmetry breaking based on scalar-meson-dominated tadpoles with σ-model-inspired meson and quark couplings is discussed.
Abstract: We discuss a dynamical mechanism forSU3 andSU2 symmetry breaking, based on scalar-meson-dominated tadpoles with σ-model-inspired meson and quark couplings. Meson and baryon mass differences are consistently described in terms of the two strange and nonstrange scalar-meson couplings to currents, and octet enhancement is obtained in a natural way.
TL;DR: In this paper, a DWBA diffractional model based on the diffraction model is presented for the analysis of direct one-step transfer cross-sections induced by heavy ions to discrete levels, and a Regge-pole analysis of alpha transfer reaction for a zero-spin system.
Abstract: Several applications of a DWBA formula based on the diffractional model and due to Blair, Austern and Hahne are presented. The applications are 1) computation of the direct one-step transfer cross-sections induced by heavy ions to discrete levels, 2) a Regge-pole analysis of alpha transfer reaction for a zero-spin system, 3) the analysis of elastic scattering with backward transfer of particles between two identical colliding cores and 4) the computation of the double differential cross-section dσ/dΩdEf of the continuum states. The DWBA diffractional formula turns out to be a powerful tool to analyse direct transfer reactions and suitable to heavy-ion transfer reactions leading to continuum states. Fast calculations are in these cases feasible, and the success stems from the fact that the formula is an analytical fit of the standard DWBA reduced matrix element.
TL;DR: In this article, the formulae found in a previous paper are used in order to give numerical values of Delbruck amplitudes for photon energies equal to 30, 50 and 70 MeV and scattering angles from 0° to 180°.
Abstract: The formulae found in a previous paper are used in order to give numerical values of Delbruck amplitudes for photon energies equal to 30, 50 and 70 MeV and scattering angles from 0° to 180°. These numerical results extend those given by other authors to a range of higher energies, where extensive calculations are generally lacking.
TL;DR: In this paper, a (n+4)-dimensional unification of Moffat's theory of gravitation and Yang-Mills' theory in Jordan-Thiry's manner was proposed.
Abstract: This paper is devoted to a (n+4)-dimensional unification of Moffat's theory of gravitation and Yang-Mills' theory in Jordan-Thiry's manner We found «interference effects» between gravitational and Yang-Mills fields which appear to be due to the skey-symmetric part of the metric on the (n+4)-dimensional manifold (nonsymmetrically metrized pricipal fibre bundle) Our unification, called the nonsymmetric non-Abelian Jordan-Thiry theory, becomes classical if the skew-symmetric part of the metric is zero
TL;DR: In this article, a phenomenological dynamical model is presented which allows us to reproduce the fusion excitation functions of a large number of systems measured experimentally, and it is shown that the dynamical fusion barriers can be, in some cases, different from the static ones.
Abstract: We use a simple parametrization of the interaction potential between two heavy ions to calculate static fusion barriers and the limit of fusion. A phenomenological dynamical model is presented which allows us to reproduce the fusion excitation functions of a large number of systems measured experimentally. The role of the dynamics on the fusion process is investigated in details and it is shown that the dynamical fusion barriers can be, in some cases, different from the static ones. The difference between them, called the dynamical energy surplus, is studied as a function of different variables and is shown to have a great influence on the fusion cross-sections.