The cosmic-ray muon momentum spectrum and charge ratio up to momenta ≃ 10 TeV/c have been measured with high accuracy. The power index of the differential spectrum of parent mesons at production gradually increases with momentum and becomes 2.87 ±0.06 in the momentum range 1 to 10 TeV/c. The charge ratio is almost constant at a value of 1.25±0.05 from 0.1 to 10 TeV/c.

The quantum one-dimensional transverse Ising model with an imaginary longitudinal field is studied at $T=0\mathrm{}$ using a real-space renormalization-group method. Evaluation is made of the real part of the ground-state longitudinal magnetization which is related to the Yang-Lee distribution of zeros of the partition function for the two-dimensional classical Ising model. The edge exponents are found as $\sigma =-0.25\mathrm{}\pm 0.05$ and $\eta =-1.0\mathrm{}\pm 0.02$, in agreement with series expansion estimates.

The statistical mechanics of the interface between two discrete thermodynamic phases is studied in terms of a field $f$ which describes the deviation of the interface from planar. Exploiting the dynamical Euclidean invariance of the Hamiltonian of the field $f$, we construct $\epsilon$ expansions for Ising-like critical behavior in $1+\epsilon$ dimensions, with a critical temperature of order $\epsilon$, Scaling functions for the interface profile and width in a pinning potential are obtained.

This Letter accounts for the observed (i) enhancement of $\frac{\Gamma (D^0\to K^{-}{K}^{+})}{\Gamma (D^0\to K^{-}{\pi }^{+})}$ and (ii) suppression of $\frac{\Gamma (D^0\to {\pi }^{-}{\pi }^{+})}{\Gamma (D^0\to K^{-}{\pi }^{+})}$ relative to ${{tan}^2\theta }_{\mathrm{C}}$ in terms of (i) the ratio $\frac{f_K}{f_{\pi }}$ of leptonic decay constants and (ii) different effective Cabibbo angles in noncharm and charm sectors. Strong new constraints on mixing angles in the six-quark model are implied.

The predictions of SU(3) for charmed-meson decay are reanalyzed, allowing for expeoted new weak-mixing angles.

The new measurement of the $D^0\to K^{-}{\pi }^{+}$, $K^{-}{K}^{+}$, and ${\pi }^{-}{\pi }^{+}$ branching ratios is compared with the range of values allowed by weak-interaction mixing angles of heavy quarks. The possibility of accommodating this measurement in the standard gauge model is discussed.

We generalize the analysis of coupling-constant renormalization in unified theories to allow for more than one scale of spontaneous symmetry breakdown between unification and SU(3) ⊗ SU(2) ⊗ U(1). We find a relation between $\alpha$, ${\alpha }_s$, ${{sin}^2\theta }_{\mathrm{W}}$, and the proton lifetime which is independent of the details of the gauge hierarchy and holds in a large class of unified theories.

This paper presents a superunified model in six dimensions using the superalgebra SU(5|1) with the vector and Higgs mesons being the various components of the gauge fields. These are fixed by the principle of infinitesimal gauge invariance to give the standard symmetry-breaking mechanism. Superheavy vector-meson masses are obtained by an additional scalar matter 24-plet. Fermions are placed in the 10 ⊕ 5 representation, and their masses examined; the theory is shown to be anomaly free.

An infinite class of nonplanar skeleton graphs is found to vanish in any non-Abelian gauge theory. Thus, the dominance of planar graphs is enhanced, particularly in processes where some momenta are very large.

We report the analysis of the spatial energy distribution of data for $e^{+}{e}^{-}\to \mathrm{hadrons}$ obtained with the MARK-J detector at PETRA. We define the quantity "oblateness" to describe the flat shape of the energy configuration and the three-jet structure which is unambiguously observed for the first time. Our data can be explained by quantum chromodynamic predictions for the production of quark-antiquark pairs accompanied by hard noncollinear gluons.

With use of the coherent-state formalism, general expressions are presented for arbitrary massless quark and gluon jet cross sections. Also, normalized probability distributions are given for the jet transverse momentum which take due account of correlations imposed by the momentum conservation. These results are used to discuss successfully the SPEAR data of Hanson et al. between 3 and 7.8 GeV.

Particle-$\gamma$ angular correlations with forty ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ angles for a fixed $\gamma$ angle have been measured for the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$)${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$*(4.44 MeV) over the energy range $14.5<~E_{\mathrm{c}.\mathrm{m}.\mathrm{}}<~32$ MeV. Satisfactory agreement with a large body of experimental data is obtained using a simple distorted-wave Born-approximation calculation without introducing the idea of "quasimolecular" resonances.

The parallel- and transverse-momentum distributions have been measured for fragments of $Z>~3$ produced by the fragmentation of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ at 90 and 120 MeV/nucleon. A strong anisotropy is observed with ${\sigma }_{p\perp }\approx 200$ MeV/c for all fragments, which can be explained by considering the dispersion due to orbital deflection of the projectile prior to breakup.

Differential elastic cross-section ratios and absolute cross sections have been measured for ${}_{}{}^{12,13}{}_{}{}^{}\mathrm{C}$ at 29.2-and 49.5-MeV average ${\pi }^{-}$ energy and for ${}_{}{}^{16,18}{}_{}{}^{}\mathrm{O}$ at 29.2 MeV. Range telescopes detected the scattered pions. The ratio data were compared with different optical-potential calculations to extract neutron radii of 2.35 ± 0.03 fm for ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ and 2.81 ± 0.03 fm for ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, relative to the neutron radii of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ (2.31) and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ (2.60), respectively. Our studies indicate little sensitivity to the optical model used.

Collisionally aided radiative excitation in a three-level atomic system is investigated with use of a stationary-phase method for the case of large atom-field detunings and weak incident fields. It is found that collision-induced coherent phase-interference effects can give rise to oscillatory structure in the total absorption cross section as a function of relative speed (energy). An example is given for a specific interatomic potential, indicating that experimental observation of such an effect is feasible.

We predict and observe the periodic reformation of spatial gratings in Na vapor commencing $\frac{\tau }{2}$ after the application of the second of two resonant ($\lambda =5896\mathrm{}$ Å) standing-wave excitation pulses which are themselves separated by $\tau$. These gratings have spatial periodicity $\frac{\lambda }{2}$, and backscatter our laser. One set of alternate echoes relaxes because of velocity-changing collisions; phase-changing collisions play no role. The other set is amplitude modulated with laser detuning $\Delta$ as $cos\Delta \tau$.

One-dimensional radial transport equations for the ELMO bumpy torus are solved numerically assuming a constant flux of cold neutrals at the plasma edge. With this boundary condition, thermal stability of numerical solutions is achieved, for the first time, in the collisionless electron regime using a fully classical transport model. Results show a parametric dependence on edge neutral pressure in the collisionless regime which is similar to that observed in experiments.

Experimental and theoretical results are presented concerning a method for providing three-dimensional spontaneous implosion of a magnetic mirror field. This is achieved by making the mirror field a propagating macroscopic wave in medium for which the wave velocity is a slowly changing function of position. Slowing down of the magnetic mirror wave causes WKB steepening and shortening—i.e., three-dimensional field compression—in a manner wherein the total magnetic field energy stays constant.

The nonlinear evolution of a single, coherent, electrostatic, ion-cyclotron wave driven unstable by a cold-ion beam directed along the magetic field is studied. When the beam energy density is large compared to the thermal energy density of the background plasma, saturation occurs by the nonlinear ion gyrofrequency shift of the background ions. Saturation amplitudes are estimated and nonlinear oscillations and solitons are shown to occur.

It is shown conclusively that electron impact ionization of the C $1s$ and O $1s$ core levels of CO adsorbed on W(100) leads to C${\mathrm{O}}^{+}$ and ${\mathrm{O}}^{+}$ desorption, respectively, and that soft-x-ray photons induce the same processes by an intrinsic photoeffect. Disintegration of the adsorption complex which becomes multiply charged by Auger decay of the core hole is assumed as explanation.