Branching ratios and CP noninvariance of nonleptonic rare exclusive B decays without charm particles in the final state are studied. Decay channels, such as ${\mathit{B}}_{\mathrm{d}}^0$→${\mathit{K}}^0$φ,${\mathit{K}}^{\mathrm{*}0}$φ, $B_s^0$→K${¯}^0$φ,K${¯}^{\mathrm{*}0}$φ, $B_d$,s→φφ,$K^0$K${¯}^0$,${\mathit{K}}^{\mathrm{*}0}$ K${\mathrm{¯}}^0$,${\mathit{K}}^0$K${\mathrm{¯}}^{\mathrm{*}0}$,${\mathit{K}}^{\mathrm{*}0}$K${\mathrm{¯}}^{\mathrm{*}0}$, etc., that can give direct evidence for the W-loop diagrams are pointed out. Some decay modes have large (tens of percent) CP noninvariance of partial-decay-rate differences. Decays such as $B_u^{+}$→$K^{+}$${\rho }^0$, ${\mathit{K}}^{+}$${\mathrm{\pi }}^{+}$${\mathrm{\pi }}^{\mathrm{-}}$,${\mathit{K}}^{+}$φ,${\mathit{K}}^{+}$${\mathit{K}}^{+}$${\mathit{K}}^{\mathrm{-}}$ might be of special interest because of the simplicity in the origin of their CP noninvariance and in their experimental detectability.

A lattice-QCD formalism for the calculation of spin-dependent potentials for heavy-quark systems is developed and applied to quark-antiquark (Q-Q¯) and quark-diquark (Q-${\mathrm{Q}}^2$) systems by use of the Monte Carlo technique. The tensor and the spin-spin terms of the potential are found to be consistent with the perturbative gluon-exchange potential. The magnitude of the Q-Q¯ potential is 2 times larger than that of the Q-${\mathrm{Q}}^2$ potential, whcih can be associated with the color factor λ⋅λ in a meson and a baryon.

The behavior of the scalar σ meson at high density is discussed in the context of the Nambu–Jona-Lasinio model. The decrease of the σ-meson mass with increasing density suggests a softening of the equation of state at high density in most of the relativistic mean-field calculations.

Searches have been performed for neutrinoless muon-electron conversion and muon-positron conversion using a time projection chamber. An upper limit on the branching ratio for the coherent reaction R(${\mu }^{\mathrm{-}}$ +Ti→$e^{\mathrm{-}}$+Ti)<4.6×1 $0^{\mathrm{-}12}$ [90% confidence level (C.L.)] relative to ordinary muon capture was obtained. For the process ${\mu }^{\mathrm{-}}$+Ti→$e^{+}$+Ca no events were observed for positron momenta p>96 MeV/c leading to an upper limit on the partial branching ratio relative to ordinary muon capture ${\Gamma }_{p>96\mathrm{}}$(${\mu }^{\mathrm{-}}$+Ti→$e^{+}$ +Ca)/Γ(${\mu }^{\mathrm{-}}$+Ti→capture) <9×${10}^{\mathrm{-}12}$ (90% C.L.). With the assumption of a giant-resonance-excitation model the integrated limit would be Γ(${\mathrm{\mu }}^{\mathrm{-}}$+Ti→$e^{+}$+Ca)/Γ(${\mu }^{\mathrm{-}}$ +Ti→capture)<1.7×${10}^{\mathrm{-}10}$ (90% C.L.).

We have succeeded in measuring at 0° and small angles the energy spectra for the (d,2p${[\mathrm{}}^1$$S_0$]) reaction (with the two protons in the singlet S state) at 650 MeV and 2 GeV. It is demonstrated that the reaction is a one-step process that can be used to study isospin-spin excitations. The Δ excitation is very clearly observed. A shift down in energy of the Δ peak from the proton to the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ target is observed. The experiments are performed with a tensor polarized beam and the tensor analyzing power for the p($d_{\mathrm{pol}}$,${\mathrm{}}^2$He)n reaction at 2 GeV is given.

Measurements have been made of the ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}=180\mathrm{}}$° cross sections for transfer reactions of ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$${+}^{116,118,120,122,124}$Sn at energies below the Coulomb barrier using a recoil mass separator. The largest single channel is for one-nucleon pickup, the cross section for which shows a strong dependence on target isotope. This dependence is correlated with the ground-state Q values for one-neutron pickup and is the same as that observed for subbarrier fusion for these systems.

The Steinwedel-Jensen hydrodynamic model is generalized to study isovector collective modes excited in charge-exchange reactions. Results are given for the energy splittings between the different isospin components of the giant dipole and monopole resonances recently observed in (p,n) and (${\pi }^{\pm }$,${\pi }^0$) reactions. The quenching of the Δ$T_z$=+1 excitation strength in N≠Z nuclei with respect to the N=Z case is also discussed.

X-ray empirical wave-function models (XEWM’s) for molecular hydrogen have been obtained by use of a density matrix formalism fitting to x-ray diffraction data. Data are derived from the Kolos-Roothaan wave function and an imposed crystal lattice. Molecular properties calculated from our XEWM’s are in excellent agreement with theoretical results. An XEWM with a crystallographic residual of ${\mathrm{R}}_{\mathrm{wF}}$=0.0007 yields a calculated binding energy of 0.1332 a.u., extremely close to the Hartree-Fock limit of 0.1336 a.u. This study demonstrates the accuracy with which XEWM’s are able to predict molecular properties from x-ray diffraction data.

An unexpected Zeeman shift discovered in recent measurements of ground-state rubidium hyperfine structure in strong magnetic fields can be explained as an effect of the hyperfine interaction in the mixing of electronic states of different principal quantum number and spin direction into the ground state. A term of the form β${\mathrm{m}}_{\mathrm{I}}^2$${\mathrm{M}}_{\mathrm{J}}$B/J is induced in the ground-state energy. A calculation based on the Fermi-Segré treatment of alkali-metal atoms yields the theoretical values β${(\mathrm{}}^{85}$Rb)=0.016 Hz/T and β${(\mathrm{}}^{87}$Rb)=0.18 Hz/T, which are in good agreement with the experimental results: β${(\mathrm{}}^{85}$Rb)=0.0162(14) Hz/T and β${(\mathrm{}}^{87}$Rb)=0.168(15) Hz/T.

We have made a very precise test of time-reversal invariance using nuclear-spin resonance in a thallium fluoride molecular beam. We searched for a shift of the 120-kHz Tl resonance when an external electric field was reversed relative to the nuclear spin and found it to be (-2.2±2.1)×${10}^{\mathrm{-}3}$ Hz, less than 0.02 ppm and a fivefold improvement over any previous measurement. Our result imposes new constraints on the proton electric dipole moment and on CP nonconservation in strong and weak interactions.

Nuclear magnetic resonance relaxation times for ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ in microscopic bubbles in 1-yr-old ${\mathrm{Pd}}^3$${\mathrm{H}}_{0.62}$ have been measured in the range 100–320 K. The results provide evidence for the melting of He in the range 200–280 K and for He diffusion in solid He below 200 K. The observed melting temperatures give a mean He atom density, from which the ratio of He atoms to host atom vacancies is found to be 2.0. An activation energy for He diffusion has been obtained and its relationship to the observed mean melting temperature is compared with that found in bulk ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ at much lower densities.

A binary mixture of hard spheres is investigated within mode-coupling theory under conditions ensuring the large particles to form an amorphous solid. The localization length of small spheres grows continuously with decreasing diameter ratio δ diverging at a critical value ${\mathrm{\delta }}_{\mathrm{c}}$≃0.15. Close to the localization-delocalization transition both the Lamb-Mössbauer and the Debye-Waller factor of the small particles show striking deviations from their commonly assumed wave-number dependence. Implications for quasielastic neutron scattering on hydrogen in (amorphous) metals are discussed.

We present a forecasting technique for chaotic data. After embedding a time series in a state space using delay coordinates, we ‘‘learn’’ the induced nonlinear mapping using local approximation. This allows us to make short-term predictions of the future behavior of a time series, using information based only on past values. We present an error estimate for this technique, and demonstrate its effectiveness by applying it to several examples, including data from the Mackey-Glass delay differential equation, Rayleigh-Benard convection, and Taylor-Couette flow.

Results from two recent ‘‘fifth-force’’ experiments disagree when analyzed in terms of a single baryonic interaction. We consider an interaction coupling to ${\mathrm{q}}_5$=B cos${\mathrm{\theta }}_5$+L sin${\mathrm{\theta }}_5$ where ${\mathrm{\theta }}_5$ has a value that could explain our null Cu-Be data while preserving Thieberger’s positive Cu-${\mathrm{H}}_2$O result. (B and L are baryon and lepton number, respectively.) We present new Al-Be data that rule out this possibility except for a narrow region around ${\mathrm{\theta }}_5$≊-63° (${\mathrm{q}}_5$∝${\mathrm{I}}_3$, the third component of isospin), where the ${\mathrm{q}}_5$ of terrestrial sources vanishes.

We show that nontopological solitons are predicted by a class of chiral models which incorporate the QCD scale anomaly. These solitons exist for all values of isospin which exceed a critical value ${\mathrm{I}}_{\mathrm{c}}$.

The (1+1)-dimensional O(N) nonlinear σ model is represented as a gauge theory with a U(1) gauge group. It is remarked that in the quantized version of the theory a dynamical Higgs phenomenon takes place. On the basis of this fact, we speculate on the existence of a similar gauge-symmetry-breaking mechanism for vector fields for which no additional fields are required.

An analysis is presented of the cross section at Superconducting Super Collider energies for events containing a large number of muons, arising from the production and decay of t quarks and of fourth-generation quark-antiquark pairs. We find that for fourth-generation masses in the range 140≤$m_Q$≤240 GeV, events containing six muons (of both signs) or four same-sign muons, with realistic momentum and rapidity cuts, will be detectable in the 0.1–1.0-pb range with essentially zero background from t-quark production or other sources.

The theoretical prediction for the decay rate of ${\Lambda }_c^{+}$→${\Lambda }^0$$e^{+}$ν greatly exceeds the measured inclusive rate for ${\Lambda }_c^{+}$→${\Lambda }^0$$e^{+}$X if ‖$V_{\mathrm{cs}}$‖ is near 1 as required by the unitarity of the Kobayashi-Maskawa matrix if there are only three generations. The discrepancy can be removed by allowing of a fourth generation. Alternatively, there may be gross errors in the standard techniques for the prediction of such decay rates or in the measurements of the ${\Lambda }_c^{+}$ decays.

The asymmetry parameter ${\alpha }_{\gamma }$ for the ${\Sigma }^{+}$→pγ decay has been measured with counter techniques. From a sample of about 190 ${\Sigma }^{+}$→pγ decays, the asymmetry parameter is found to be ${\alpha }_{\gamma }$=-0.86±0.13±0.04, where the quoted errors are statistical and systematic, respectively. The present result confirms with better accuracy the large and negative value for ${\alpha }_{\gamma }$ measured by two previous bubble-chamber experiments. The branching ratio is also found to be (1.30±0.15) ×${10}^{\mathrm{-}3}$, which is consistent with previous measurements.

We report on the numerical evidence of a new class of low-energy e+${\mathrm{H}}^{+}$ scattering resonances which dominate the field-modified elastic (Rutherford) and the inelastic (inverse bremsstrahlung) scattering cross sections in the presence of a strong excimer laser.