Showing papers in "Nuovo Cimento Della Societa Italiana Di Fisica A-nuclei Particles and Fields in 1978"
TL;DR: In this paper, it was shown that the elementary treatments of the Aharonov-Bohm effect are vitiated by a false conception of the electron wave phase, and that the effect is a consequence of an improper choice of the initial condition, or an improper Green's propagator for the initial wave function.
Abstract: Some theoretical points of a previous paper on the same subject are further developed. In particular, it is shown that 1) the elementary treatments of the Aharonov-Bohm effect are vitiated by a false conception of the electron wave phase; 2) the Aharonov-Bohm effect is a consequence of an improper choice of the initial condition, or—alternatively—of the choice of an improper Green's propagator for the initial wave function. Then, the most significant experiments on the Aharonov-Bohm effect are discussed; it is shown that they are not probative, and a simple explanation is proposed.
99 citations
TL;DR: In this article, properties of 3n-quark systems in the spherical-cavity approximation of the MIT bag model are considered, and the appearance of hidden colour baryonie mixtures in multibaryonic states is emphasized.
Abstract: Properties of the 3n-quark systems in the spherical-cavity approximation of the MIT bag model are considered. Results concerning the kinematies—colour restrictions, baryon composition—as well as the dynamies—mass formulae, magnetic moments, gluon corrections—of such states are obtained via a group-theoretical treatment. The appearance of «hidden colour» baryonie mixtures in multibaryonic states is emphasized, and the role of the quark-gluon interaction illustrated.
56 citations
TL;DR: In this paper, a complete cluster analysis of the one-particle momentum distribution of a quantum fluid, based on the power series expansion, is presented, and a set of integral equations whose solutions allow for an exact calculation of the momentum distribution is derived.
Abstract: A complete cluster analysis of the one-particle momentum distribution\(n_{\hat q} \) of a quantum fluid, based on the power series expansion, is presented. The expansion is shown to be linked and it is demonstrated that\(n_{\hat q} \) may be written asnN(q), where both lnn andN(q) are given by a series of irreducible cluster contributions. A set of integral equations whose solutions allow for an exact calculation of\(n_{\hat q} \) is derived.
54 citations
TL;DR: In this paper, the relevance of the Coulomb de-excitation in the early stages of the cascade of neutral exotic atoms is pointed out, and the effect is shown to be dominant forn≳10 and for a large interval of pressure values.
Abstract: Some aspects of the cascade of neutral exotic atoms are analysed. In particular the relevance of the Coulomb de-excitation—transitions induced by the Coulomb interaction with the surrounding atoms—is pointed out. Cross-sections and rates are calculated for μ−p and π−p atoms in hydrogen with energies ranging between 0.1 and 10 eV. The effect turns out to be dominant forn≳10 and for a large interval of pressure values. The consequence is a drastic shortening of the early stages of the cascade. When considered for π−p atoms, the effect provides a better agreement between the theoretical and experimental cascade times than that previously found.
53 citations
Journal Article•
40 citations
TL;DR: In this paper, the canonical formalism of a singular-Lagrangian model describing the interaction between two relativistic particles is studied and the covariance and quantization of the model are discussed.
Abstract: The canonical formalism of a singular-Lagrangian model describing the interaction between two relativistic particles is studied. Instead of following the Dirac method, we make use of a canonical transformation that enables us to work in the complete phase space. The covariance and the quantization of the model are discussed.
40 citations
TL;DR: In this paper, the power series cluster expansion has been derived for an infinite fermion system described by a state-dependent Jastrow correlation function, and the resulting terms have been classified and separated into two groups.
Abstract: The power series cluster expansion has been derived for an infinite fermion system described by a state-dependent Jastrow correlation function. The resulting terms have been classified and separated into two groups. In the first group all the irreducible terms not containing commutators are included and they are summed up by means of a FHNC procedure wich requires the solution of a set of integral equations. The second group is constituted by terms containing commutators and it is suggested that their complessive contribution should be small: the preliminary numerical calculations are in agreement with this suggestion.
37 citations
TL;DR: In this paper, a single-particle quantum formalism for spin-zero particles based upon state functions and operators defined on a four-dimensional space-time manifold was constructed. But this formulation requires that particle mass be treated as an observable, not as a specified constant.
Abstract: A single-particle quantum formalism is constructed for spin-zero particles based upon state functions and operators defined on a four-dimensional space-time manifold. This yields a generalized Schrodinger equation having a Hermitian Hamiltonian and a derivative with respect to proper time. This formulation requires that particle mass be treated as an observable, not as a specified constant. A consistent probability interpretation results and a proper classical limit is exhibited. It is proposed that this formalism should properly replace the conventional Klein-Gordon formalism.
34 citations
TL;DR: In this paper, the construction of a complete, orthonormal set of complex energy states is first discussed for a general Hamiltonian and then illustrated in detail for a new solvable model.
Abstract: Properties of complex energy solutions to the Schrodinger equation are studied in a spectral representation of the type used in the Lee-Friedrichs model of unstable states. The construction of a complete, orthonormal set of complex energy states is first discussed for a general Hamiltonian and then illustrated in detail for a new solvable model. This model determines normalizable eigenvectors corresponding to resonant solutions to the eigenvalue equation for a simple potential scattering problem.
34 citations
TL;DR: In this article, an organic exposition is given of a new quantum theory of the electron based on the introduction of the chronon in physics, which is developed essentially without the need of any new hypothesis beyond those adopted for the formulation of the classical theory, developed many years ago by the author to overcome some typical difficulties of the Lorentz-Dirac theory.
Abstract: In this paper an organic exposition is given of a new quantum theory of the electron based on the introduction of the chronon in physics. Such a theory is developed essentially without the need of any new hypothesis beyond those adopted for the formulation of the classical theory of the electron developed many years ago by the author to overcome some typical difficulties of the Lorentz-Dirac theory. From the new quantum theory of the electron it is possible to derivea) the interpretation of the muon as an excited state of the electron;b) the prediction of the existence of a heavy electronlike charged lepton e(2) having a massM(2)=(3/2 (ħc/e2))2m0 ⋍ 23 protonic masses;c) an indication for the possibility of existence of another heavy muonlike charged lepton e(3), extremely unstable, having a massM(3)=(3/2 (ħc/e2))3m0 ⋍ 4740 protonic masses;d) the existence of a whole spectrum of « virtual » charged heavy leptons e(n) having massesM(n)=(3/2 (ħc/e2))nm0 (withn>3), electronlike for evenn and muonlike for oddn;e) the existence of a whole spectrum of neutrinos having massesmv(n)=(gW2/e2)M(n) both electronlike (evenn) and muonlike (oddn); those withn>3 are connected to the « virtual » heavy leptons. Moreover, the electronlike heavy lepton e(2) may be conceived as related to the heavy vectorial meson W introduced in the theory of weak interations by Abdus Salam and by Weinberg. The heavy electron e(2) might also be responsible, in addition to the heavy vectorial mesons, for some anomalies observed in the cosmic radiation. Finally the values of the neutrino masses predicted by our theory appear not to be in disagreement with the bounds that can be established on the basis of the experiments on the Pontecorvo oscillations and of various kinds of observations concerning the astrophysical environment.
30 citations
TL;DR: In this paper, the infinite part of these diagrams is found very easily, also if they are overlapping, and the separation of the several kinds of divergences comes out quite naturally.
Abstract: Dimensionally regularized Feynman diagrams are represented by means of products ofk-functions. The infinite part of these diagrams is found very easily, also if they are overlapping, and the separation of the several kinds of divergences comes out quite naturally. Ward identities are proven in a transparent way. Series expansions in terms of the external momenta and their inner products are possible.
TL;DR: In this article, the reaction of the K-meson conspiracy and the exchange of the k*K** degenerate trajectory associated with a Regge cut was studied in a bubble chamber experiment at eight incident momenta between 1.50 and 2.06 GeV/c.
Abstract: The reaction\(\bar pp \to \bar \Lambda \Lambda \) has been studied in a bubble chamber experiment at eight incident momenta between 1.50 and 2.06 GeV/c. The differential cross-section, the polarization and the spin correlation coefficients have been measured. They have been compared with the prediction of two theoretical models: the K-meson conspiracy and the exchange of the K*K** degenerate trajectory associated with a Regge cut. The latter model gives the best representation of the data.
TL;DR: In this paper, an approach to quantization of a free matter field in curved space-time is presented which takes advantage of the existence of infinitely many unitarily inequivalent Fock representations.
Abstract: An approach to the quantization of a free matter field in curved space-time is presented which takes advantage of the existence of infinitely many unitarily inequivalent Fock representations. The construction describes a particle creation mechanism, which, in the case of black-hole metric, has many properties of the Hawking process. The renormalizability of the theory is proved at the one-loop order. In this respect a crucial role is played by the contributions coming from the unitarily inequivalent representations of the canonical commutation relations.
TL;DR: In this article, the low-energy πK scattering amplitudes consistent with crossing, unitarity and thet-channel information are obtained by combining fixed-t and hyperbolic dispersion relations.
Abstract: The low-energy πK scattering amplitudes consistent with crossing, unitarity and thet-channel information are obtained by combining fixed-t and hyperbolic dispersion relations.
TL;DR: In this article, the authors describe a nuclear event of new character observed in an emulsion chamber exposed on Mt. Chacaltaya, where the interaction has its vertex within the chamber and contains 40 γ-rays, whose energies sum up to ∼42 TeV.
Abstract: We give a description of a nuclear event of new character observed in an emulsion chamber exposed on Mt. Chacaltaya. The interaction has its vertex within the chamber and contains 40 γ-rays, whose energies sum up to ∼42 TeV. The most remarkable feature of the event are: 1) Abnormally large transverse momenta. The average transverse momentum of the γ-rays is ∼0.5 GeV/c. 2) Abnormally high transverse-momentum density. That of the γ-rays is (70÷90) GeV/c per unit log tgϑ interval. 3) Multijetlike angular structure. At least three structures are observed. 4) Noncoplanarity. The γ-ray momentum distribution deviates appreciably from a coplanar one. If a fireball picture is adopted, the event can be interpreted as a production of a giant fireball, out of whose rest energy an energy of (60÷80) GeV is liberated in the form of γ-rays, and which decays into hadrons through smaller fireballs. The highest-energy γ-ray pair starts in an empty space within the chamber, suggesting that they come from a parent particle with a lifetime of the order of 10−13 s.
TL;DR: In this paper, the existence of unphysical solutions for a large class of models can be drawn from an analysis of the location of the poles of the Green's function, and a new condition for the nonexistence of pathological solutions is discussed.
Abstract: Starting from a covariant equation, we have shown how a consistent equation of motion and an equation for the energy balance are achieved in the nonrelativistic limit. In that limit we can integrate such an equation for any charge distribution by finding its Green’s function. Conclusions concerning the existence of unphysical solutions (and explicit solutions for a large class of models) can be drawn from an analysis of the location of the poles of the Green’s function. A new condition for the nonexistence of pathological solutions is discussed.
TL;DR: In this paper, the generalized zetafunction was applied to the regularization of the effective potential of the one-loop effective potential at finite temperature and in an uniform magnetic field in a few models of field theory.
Abstract: The aim of this paper is to apply the generalized zetafunction to the regularization of the effective potential. This method is exemplified by the calculation of the one-loop effective potential at finite temperature and in an uniform magnetic field in a few models of field theory. The zeta-function regularization avoids the subtraction of any pole term or the addition of infinite counterterms.
TL;DR: In this paper, a classical theory of the electron, proposed by one of us several years ago and based on finite-difference equations, is discussed by considering the three possible following cases: radiating electron, absorbing electron and nonradiating, nonabsorbing electron.
Abstract: A classical theory of the electron, proposed by one of us several years ago and based on finite-difference equations, is discussed by considering the three possible following cases: radiating electron, absorbing electron and nonradiating, nonabsorbing electron. In particular the so-called transmission laws necessary to determine, in conjunction with the dynamical equations, the motion of a charged particle corresponding to given initial values of position and velocity are critically reconsidered. The general characteristics of the one-dimensional motion in the non-relativistic approximation are discussed in detail. It is found that in the case of the radiating electron the particle position tends asimptotically to the point of stable equilibrium. The present theory is, therefore, free from the unphysical phenomenon of runaway solutions. These general results are illustrated by studying the motion of a particle under the action of a restoring elastic force and under the action of purely time-dependent forces.
TL;DR: In this article, a lepton-hadron relation is proposed to explain some interesting features of the multiparticle production processes and the approximate global nature of the average multiplicities in deep inelastic scatterings.
Abstract: On the basis of a lepton-hadron relation which takes muonic leptons as the basic constituents of hadrons, we attempt here to explain some interesting features of the multiparticle production processes and the approximate global nature of the average multiplicities in deep inelastic pp, πOpen image in new window and eOpen image in new window scatterings. The application of the model shows that the validity of scale invariance at low transverse momentum and the violation of scale invariance at high transverse momentum are not two exclusively different phenomena, but just the two-tier behaviour of the same multiparticle production mechanism at two varying values of transverse momentum corresponding to different (high or ultrahigh) energy regions. The model links up the question of multiplicity growth with energy—logarithmic rise at low transverse momentum and power law increase at high transverse momentum as demanded by some high-energy experiments. This also explains some other features, such as angular independence of the multiple-production cross-section for wide-angle scatterings. The model claims a major success in accounting for the nearly uniform average multiplicities in a nice way in various high-energy scattering experiments from the dynamics of collision of the pointlike constituents of hadrons.
CERN1
TL;DR: In this paper, the first-order corrections of the naive parton model for the one-hadron inclusive virtual photoproduction were calculated in a SU3, colour ×SU3, flavour invariant interaction of quarks and gluons.
Abstract: In aSU3, colour ×SU3, flavour invariant interaction of quarks and gluons, where the colour degree of freedom is locally gauged, we calculate first-order corrections of the naive parton model for the one-hadron inclusive virtual photoproduction. We study the high-pT distribution of hadrons and we determine the kinematical region in which the prediction of the model dominates over the fall-off ∼ exp [−bpT2] which seems to be supported by the low-pT available experimental data.
TL;DR: In this article, the positive-definiteness property of the two-point correlations of the bidimensional Ising model in the scaling limit atT≠Tc was verified.
Abstract: We verify explicitly the positive-definiteness property of the two-point correlations of the bidimensional Ising model in the scaling limit atT≠Tc. In the scaling limit atT=Tc we give a representation of the aligned correlations in terms of Gaussian expectation values of exponentials of free fields.
TL;DR: In this paper, a two-component model of high-energy interactions is presented, consisting of a three-fireball (inelastic) plus two-fireballs (mainly elastic) structure.
Abstract: A new two-component picture of high-energy interactions is advanced. It consists of a three-fireball (inelastic) plus two-fireball (mainly elastic) structure. A somewhat simplified version is applied to pp multiplicities at machine energies. Very good fits are obtained, particularly if one excludes in the fitting procedure the occasional “erratic” data point. A comparison is made with a variant of the model which reduces to a conventional sum of two Poisson terms.
TL;DR: In this article, the binding energies and lifetimes of stable charmed hyperfragments formed by C0 and nucleons are discussed, and the bound energies and lifetime of these structures are estimated.
Abstract: Stable charmed hyperfragments formed by C0 and nucleons are discussed. Estimates are given for binding energies and lifetimes. Among light charmed hyperfragments\(^5 He_{C_0 } ,^4 He_{C_0 } ,^4 H_{C_0 } , and ^3 H_{C_0 } \) are probably bound and live (10−14÷10−13) seconds.
TL;DR: In this article, a relation for Cohen's kernel is obtained, which shows the inconsistency of quantization rules with Dirac's correspondence, and the same relation is used to find the special classes of observables for which the more common quantisation rules preserve Dirac correspondence.
Abstract: A classical relation for Cohen’s kernel is obtained, which shows the inconsistency of quantization rules with Dirac’s correspondence. The same relation is used to find the special classes of observables for which the more common quantization rules preserve Dirac's correspondence.
TL;DR: In this paper, the energy spectra of the ψ family of mesons, the Υ family and a possible new ζ family, using the quark model with a Coulomb-like potential at small distances and a linear potential at large distances, both modified by logarithmic factors.
Abstract: We calculate the energy spectra of the ψ family of mesons, the Υ family and a possible new ζ family, using the quark model with a Coulomb-like potential at small distances and a linear potential at large distances, both modified by logarithmic factors. We also calculate the leptonic-decay widths of vector mesons of these families. We include the effects of spin-dependent forces in perturbation theory. In the case of the ψ and Υ families, we compare the predictions of the model with experiment.
TL;DR: In this article, an appropriate connection is found on such bundles, and the connection supports a projective realization of the structure group, which provides an example of gauge theories in which the number of independent gauge fields is smaller than the dimension of the local symmetry group.
Abstract: Classical gauge theories are constructed on a class of associated bundlesS(M, G; G/A), with structure groupG, the fibre being isomorphic to a coset space ofG. An appropriate connection is found on such bundles. The connection supports a projective realization of the structure group. The connection coefficients may be identified as gauge potentials. This construction provides an example of gauge theories in which the number of independent gauge fields is smaller than the dimension of the local symmetry group.
TL;DR: In this article, the symmetry of the wave functions of identical particles is related to the presence of a global gauge effect, which is used to investigate in detail the statistics of composite particles which are bound systems of a charged particle and a magnetic monopole.
Abstract: A formalism is described in which the symmetry of the wave functions of identical particles is related to the presence of a global gauge effect. The formalism is used to investigate in detail the statistics of composite particles which are bound systems of a charged particle and a magnetic monopole. For such composites the phase factor which determines their statistics can be shown to be influenced by the gauge field which is present.
CERN1
TL;DR: In this paper, the authors suggest that nuclear Compton scattering below meson production threshold can provide a fundamental tool in the analysis of the exchange effects in nuclei and evaluate exchange terms and show that they strongly affect the diffractive behaviour even in the low-momentum-transfer region.
Abstract: We suggest that nuclear Compton scattering below meson production threshold can provide a fundamental tool in the analysis of the exchange effects in nuclei We evaluate exchange terms and show that they strongly affect the diffractive behaviour even in the low-momentum-transfer region
TL;DR: In this article, a balloon-borne telescope containing four Ĉerenkov counters and a neon flash tube hodoscope was used to measure abundances of the light elements in cosmic rays.
Abstract: Abundances of the light elements in cosmic rays were measured with a balloon-borne telescope containing four Ĉerenkov counters and a neon flash tube hodoscope. In order to extract Li events from the surrounding background of proton and He interactions in the instrument, an event was rejected if the hodoscope indicated the presence of more than one particle near the top of the instrument. The selection strategy led to essentially complete charge separation between He and Li. Some events were lost because the hodoscope was sensitive to δ-electrons; a correction for the charge dependence of this loss was carried out, affecting the measured Li/B ratio by ∼2%. Ratios between integral fluxes were measured above a geomagnetic cut-off ∼1.9 GV/c and above 650 MeV/nucleon kinetic energy. Li/B ratios found in the two cases were 0.73±0.05 and 0.70±0.05; the Li/C ratio was found to be 0.21±0.02 in both cases. These results agree with Li abundances reported by several other observers. They also agree with Li/B ratios predicted from a leaky-box type of propagation model as well as from a recent two-component model by Peters and Westergaard.
TL;DR: In this paper, the authors investigated the effect of the Landau-Pomeranchuk-Migdal effect in the processes of bremsstrahlung and pair production by using the full Monte Carlo method.
Abstract: Cascade showers in the ultrahigh-energy region are investigated, by taking into account the Landau-Pomeranchuk-Migdal effect in the processes of bremsstrahlung and pair production by the use of the full Monte Carlo method. Calculations are carried out in both one dimension and three dimensions and mean values, such as numbers of shower particles, mean square angular and lateral spread of particles and lateral structure functions, are obtained. These quantities are compared with results from cascade theory under approximationA and their features are discussed. The validity of the Monte Carlo method adopted is checked in individual processes in a cascade shower and is examined as a whole by comparing results from the simulation with those from the corresponding analytical theory.