ISSN / EISSN : 0031-899X / 1536-6065
Published by: American Physical Society (APS) (10.1103)
Total articles ≅ 47,965
Latest articles in this journal
Physical Review, Volume 188, pp 2458-2464; https://doi.org/10.1103/physrev.188.2458
On the basis of the current-field-identity relation, a unified treatment and quantitatively successful calculation of pion production by ρ mesons and photons is presented. The model, which is independent of free parameters, explains the empirically established facts about strong mass dependences in the ρ density matrix elements (in particular, also in the combination ρ11+ρ1−1) considered as a function of the mass k2 of the ρ meson. These facts have been the basis for a recent criticism of the vector-meson-dominance hypothesis in pion production. But our results indicate that the current-field-identity relation is not in conflict with experiment. We emphasize in our discussion that no model-independent formulation of vector-meson dominance is possible in pion production, according to our present knowledge.
Physical Review, Volume 188, pp 2465-2468; https://doi.org/10.1103/physrev.188.2465
It is shown that the contributions to the Adler-Weisberger sum rule (AWSR) in the simplest Veneziano model for K−π scattering are too large by a factor of 2. A modification of the simplest Veneziano amplitude is proposed which satisfies (i) the Adler self-consistency condition, (ii) the AWSR, and (iii) the K*(890) having the experimentally observed width of 50 MeV. If this modified Veneziano amplitude is required to satisfy the Adler-Weisberger-type sum rule for zero-mass K mesons scattering from physical pions, the ratio FKFπ is predicted to be 1.26, in good agreement with experiment.
Physical Review, Volume 188, pp 2534-2535; https://doi.org/10.1103/physrev.188.2534
For any spin, the Coulomb bound states can be described by an irreducible unitary representation of O(4, 1). The relativistic Coulomb problems that have been solved (spins 0 and ½) are described in this way.
Physical Review, Volume 188, pp 2536-2538; https://doi.org/10.1103/physrev.188.2536
The unitarity relations for the decay of overlapping resonances as obtained by an S-matrix approach and the usual Wigner-Weisskopf approach are compared.
Physical Review, Volume 188, pp 2541-2542; https://doi.org/10.1103/physrev.188.2541
A discrepancy is found between the two-meson solution of charged scalar theory given by Bronzan and the isobar spectrum known from strong-coupling theory. The discrepancy is traced to a failure of production amplitudes to satisfy crossing symmetry.
Physical Review, Volume 188, pp 2154-2158; https://doi.org/10.1103/physrev.188.2154
A crossing-symmetric Regge-pole model of the generalized interference type is discussed. The model consists of a sum of infinitely many Regge poles in each channel, corresponding to a leading Regge trajectory and its parallel daughters. All the usual requirements are satisfied by the Regge residues, and nonlinear trajections can be introduced without difficulty. At the expense of a loss of physical interpretation, the double-counting problem can be eliminated by identifying the Schmid loops with the direct-channel resonances.
Physical Review, Volume 188, pp 2274-2276; https://doi.org/10.1103/physrev.188.2274
We present here a derivation of Weinberg's formulas for the algebraic structure of current algebra and superconvergence sum rules in the case of massive pions, using the infinite-momentum method. We show that Weinberg's formulas are closely related to the fact that there is no T=2 part in some double commutation relations between axial charges Q5a, Q5b and the generators of inhomogeneous Lorentz transformations.
Physical Review, Volume 188, pp 2277-2280; https://doi.org/10.1103/physrev.188.2277
The ω−φ mixing angle of SU(3) is usually assumed to be positive, but only its magnitude is actually determined by various models of SU(3) breaking. The effect of this ambiguity of the relative sign of the SU(3) prediction of the γ−ρ and γ−ω coupling constants on ρ−ω interference is investigated. The interference can be "constructive" or "destructive." In photoproduction of lepton pairs, destructive interference causes the effect of ρ−ω interference to be smaller than that of previous calculations. Two new models of ρ−ω interference in the colliding-beam reaction e++e−→π++π− are discussed. A measurement of the cross section for the latter reaction would make possible a determination of the sign of the ω−φ mixing angle.
Physical Review, Volume 188, pp 2281-2283; https://doi.org/10.1103/physrev.188.2281
Relations between processes related by crossing are proposed as a test of (i) exchange degeneracy and (ii) dominance by trajectories of the same signature. Various possible experiments are discussed.
Physical Review, Volume 188, pp 2283-2286; https://doi.org/10.1103/physrev.188.2283
A sequence of amplitudes for ππ→πω is constructed exhibiting exact crossing symmetry, Regge asymptotic behavior, direct-channel poles, and arbitrary nonlinear trajectories. The sequence, constructed out of the elementary symmetric functions of s, t, and u, possesses some of the desired features in a limiting sense only. In the complex angular momentum plane, any member of the sequence contains a leading finite array of simple poles spaced by two units, and additional nonleading arrays of higher-order singularities. A similar amplitude for the elastic scattering of neutral scalar bosons is proposed to test the unitarizability of the representation by finding a suitable nonlinear trajectory.