7913664
Energy dependence of pion inelastic scattering to the 1(+) states in 12C.
The energy dependence of cross sections for inelastic pion scattering to the /Delta/ = /Delta/ = /Delta/ = 1 transition at 15.11 MeV in /sup 12/C is found to map very closely the /Delta/ = /Delta/ = /Delta/+1 /pi/-nucleon scattering cross sections at beam energies from 50 to 295 MeV. This free /pi/-nucleon energy dependence is due to the prominent /Delta/sub 3/2,3/2/ resonance, corresponding to the first excited nucleon state, which is mirrored in the /pi/-nucleus system with little alteration.
121596205
Solution of the equations for the green’s functions of a two dimensional relativistic field theory
SummaryThe explicit solution of the coupled set of equations for the Green’s functions for the self-coupled field theory model of Thirring is given. It is found that the infra-red problem causes no special difficulty. The question of how to define products of singular field operators at coincident space-time points arises and it is shown that the commutation relations for such products are not consistently given by making use of the formal expressions and the canonical commutation relations. The problem of gauge invariance in an external field is studied and it is shown that:a) the current and charge density do not commute at equal times, andb) this is necessary for and consistent with the gauge invariance of the field equations.RiassuntoSi dà la soluzione esplicita del gruppo accoppiato di equazioni per le funzioni di Green per il modello auto-accoppiato della teoria del campo di Thirring. Si trova che il problema infrarosso non genera particolare difficoltà. Sorge la questione sul modo di definire i prodotti degli operatori di campo singolari in punti coincidenti dello spaziotempo e si mostra che le relazioni di commutazione per questi prodotti non vengono espresse coerentemente facendo uso delle espressioni formali e delle relazioni di commutazione canonica. Si studia il problema della invarianza di gauge in un campo esterno e si mostraa) che la corrente e la densità di carica non commutano in tempi uguali, eb) che questo è necessario per l’invarianza di gauge delle equazioni del campo, e coerente con essa.
120478935
Vacuum polarization in quantum electrodynamics
116403039
THE M.I.T. BAG, 1976 EDITION
We assume (1,2) that hadrons consist of colored quarks and gluons, and that the dynamics is described by the standard non-Abelian gauge field theory. However, we also assume that space exists in two phases. In the first phase, I, ordinary space, colored fields are not carried on the spatial points. In the second phase, II, which is the kind of space inside hadrons, the spatial points carry colored field variables; Further, we assume that the second kind of space carries an energy per unit volume, BGT0, greater than the first kind and that the second kind of space can exist as bubbles in the first kind. This is done in a relativistically covariant way, by associating with the second kind of space a local stress-energy of the form, -gμν B. The phase II space is called a bag.
122229005
Simple semiclassical model for the rotational states of mesons containing massive quarks
We present a semiclassical relativistic model for the orbital spectra of mesons, based on the assumption of a universal, flavor-independent linear confining interaction. Flavor dependence of the spectra arises from the quark masses.
116663050
The Quark Model Pion and the PCAC Pion
An important problem in the theory of strong interactions is furnished by the least massive hadrons, the pseudoscalar meson octet. The difficulty is that there are two such octets.
36028712
Driven response of a trapped particle beam.
The dynamics of a metastable beam of particles injected'' into artificially excited resonance islands in the Fermilab Tevatron is studied. Evolution of the captured beam distribution is measured by an externally detectable coherent signal. Dynamical partitions observed in the control space of amplitude and tune of a focusing modulation are consistent with an equivalent mode of an ensemble of driven gravity pendula. The model's single parameter, the island tune {ital Q}{sub {ital I}} of small oscillations, is inferred as the central frequency of resonant detrapping under this weak drive.
11984264
Low-energy technicolor Lagrangian with vector mesons.
We apply techniques used in QCD and the implied chiral symmetry to motivate a low-energy Lagrangian for technicolor theories. This allows one to cleanly introduce the gluon and the weak gauge bosons at the technifermion level. The Higgs mechanism and techni-vector-meson dominance are displayed. The effect of vector dominance on the {ital W} and {ital Z} masses, the techni-{omega} and techni-{rho} couplings, and the sizable enhancement by the latter on {ital W} and {ital Z} production are demonstrated. Differences between our results and some published results are discussed. The incorporation of extended technicolor interactions is also presented.
36956553
Scale anomaly and the scalars.
We investigate the properties of a possible low-lying scalar glueball as well as the ordinary scalar-quark states using an effective chiral Lagrangian which satisfies the trace anomaly and U(1)/sub A/ anomaly of QCD. An interesting mass bound for the lightest particle in the scalar-singlet channel is discussed. Detailed arguments against the existence of a very light (less than 400 MeV) scalar glueball are presented. It is shown that the introduction of a derivative-coupling term in the usual type of linear sigma model cures the problem of excessively large widths for the ordinary (nonet) scalar mesons. In fact, chiral symmetry enables one to nicely correlate the widths of the entire scalar nonet. It is noted that the same derivative-coupling term allows a heavy (1-2 GeV) scalar glueball to have sufficiently narrow width to permit its observation as an ordinary resonance, in contrast with a recent claim. Our model can naturally explain the unusually large partial width for the etaeta' mode of the glueball candidate G(1590). A symmetrical ansatz for the anomaly terms is suggested which enables one to successfully calculate the eta' mass as the ratio of gluon condensate to pion-decay constant. In addition, the theoretically interesting limit where the glueballmore » becomes a true dilaton is formulated in a new and illustrative way.« less
26932934
Measurements of a Hamiltonian system and their description by a diffusive model.
The dynamics of transverse particle oscillations in the Fermilab Tevatron, artificially made nonlinear, is studied by observing beam profiles over periods up to an hour. A ``diffusive'' model with amplitude-dependent diffusion coefficient gives a quantitatively accurate description of beam evolution. The evolution is influenced strongly by nonlinear resonance.
7811061
Atomic-weight dependence of the production of hadron pairs by 800-GeV/c protons on nuclear targets.
Fermilab experiment 711 has investigated proton-nucleus collisions in which two high-transverse-momentum hadrons are produced forming high-mass ++, +{minus}, and {minus}{minus} charged states, using an 800-GeV/{ital c} proton beam on targets of beryllium, aluminum, iron, and tungsten. Our data cover the range in dihadron mass from 6 to 15 GeV/{ital c}{sup 2}. We show here that the dependence of the cross section on atomic weight {ital A} can be parametrized as {ital A}{sup {alpha}} where {alpha}=1.043{plus minus}0.011(stat){plus minus}0.025 (syst), and is independent of the charge state of the dihadron system.