A new reaction-mechanism-independent method is proposed for determining spins of nuclear levels from angular correlations between $\alpha$ particles and heavy ions. This is an alternative approach to the well-known Method II of Litherland and Ferguson, permitting geometry other than 0° or 180° for the detection of the reaction particle.

Quasi-rotational bands built on the ${\frac{7}{2}}^{+}$ and ${\frac{11}{2}}^{-}$ states in ${}_{}{}^{101}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{103}{}_{}{}^{}\mathrm{Pd}$, and ${}_{}{}^{105}{}_{}{}^{}\mathrm{Pd}$ and the ${\frac{5}{2}}^{+}$ state in ${}_{}{}^{101}{}_{}{}^{}\mathrm{Pd}$ have been excited by (heavy-ion, $\mathrm{xn}$) reactions. ($d, p$) and ($d, t$) reactions have been used to show that the absence of the ${\frac{5}{2}}^{+}$ band in ${}_{}{}^{103}{}_{}{}^{}\mathrm{Pd}$ and ${}_{}{}^{105}{}_{}{}^{}\mathrm{Pd}$ is related to the fragmentation of the $d_{\frac{5}{2}}$ quasiparticle strength in these nuclei. An unusual relation has been found between the type of reaction used and the detection of quasirotational bands in odd-$A$ nuclei.

Using satellite data obtained over the polar regions during the solar active period of 30 October through 2 November 1972, we obtain upper limits to the ${}_{}{}^2{}_{}{}^{}\mathrm{H}$/${}_{}{}^1{}_{}{}^{}\mathrm{H}$ and ${}_{}{}^3{}_{}{}^{}\mathrm{H}$/${}_{}{}^1{}_{}{}^{}\mathrm{H}$ ratios: 1.4 × ${10}^{-5\mathrm{}}$ (3.1-30.6 MeV/nucleon) and 9 × ${10}^{-6\mathrm{}}$ (2.4-23.0 MeV/nucleon), respectively.

We report a preliminary search for a positively charged lepton ($Y^{+}$) coupled directly to the ${\mu }^{-}$ and ${\nu }_{\mu }$ (i.e., muon number = + 1). Using the production process ${\nu }_{\mu }+N\to Y^{+}+\mathrm{anything}$, we have looked for the ${\mu }^{+}$ from the decay $Y^{+}\to {\mu }^{+}+{\nu }_{\mu }+{\nu }_{\mu }$. The expected number of ${\mu }^{+}$ events is given as a function of the heavy-lepton mass, the branching fraction to muons, and the heavy-lepton coupling. For typical gauge-theory predictions, we obtain the 90% confidence limit $M_Y>2\mathrm{}$ GeV/${\mathit{c}}^2$.

Inclusive ${\pi }^{-}$ distributions from 205-GeV/c $\mathrm{pp}$ interactions, covering the full range of longitudinal and transverse momenta, have been obtained using the 30-in. hydrogen bubble chamber at the National Accelerator Laboratory. These data provide new evidence for scaling in the fragmentation region and for a plateau in the central region of rapidity. The 90°-c.m. invariant cross section varies as $\exp [-(10\mathrm{}\pm 2\left){P_T}^2\right]$ in the range ${P_T}^2<~0.1$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$.

The $3s3p{{}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}}^{\circ }$ level of Mg i has been selectively excited by the second harmonic of the output of a high-power, narrow-band, frequency tunable dye laser. The excited-state absorption series $3s3p{{}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}}^{\circ }-3\mathrm{snd}{}_{}{}^1{}_{}{}^{}D_2^{}{}_{}{}^{}$ has been recorded to $n=24\mathrm{}$. A strong autoionization resonance has been obtained at $\lambda =300.9\mathrm{}$ nm, with a photoionization cross section of ∼5 × ${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$, in very good agreement with the values predicted by calculation.

Exact hydrogenic (EH) Compton-profile calculations have been performed for the $L$ shell of neon. For the scattering of Mo $K\alpha$ and Ag $K\alpha$ radiation from neon the EH calculations show the Mo $K\alpha$ profile to lie higher at the center, in agreement with the experimental results of Eisenberger. An accurate configuration-interaction impulse Compton profile for neon is calculated and it is observed that the effect of correlation of $J\left(0\right)\mathrm{}$ is significantly smaller than reported earlier.

An expression is given for the Stark-induced beat signal in the Lyman-$\alpha$ radiation from hydrogen atoms in a beam-foil experiment. This expression includes possible contributions to the beat signal from coherent excitation of $S$ and $P$ states in the beam-foil process. For the case where the electric field is applied parallel to the beam, the coherentexcitation contributions can be separated experimentally from those resulting purely from coherence produced by the electric field, by simply reversing the direction of the electric field.

We observe very narrow (∼200 Hz) magnetic resonance lines in alkali vapors with atomic densities much greater than usual and with cell dimensions much smaller than usual. The Zeeman resonance frequency is shifted downward by a large factor, but the spin-exchange broadening vanishes in the high-density limit. This new regime affords important new possibilities for investigating basic interactions in dense alkali vapors, and it also opens the way to miniaturized optically pumped devices.

We exhibit a dynamical model of particles in a two-dimensional lattice. We study a particular class of equilibrium states, and we investigate the simplest time correlation functions for these states. As a consequence, the propagation of sound waves with velocity $\frac{1}{\sqrt{2}}$ can be proved rigorously. A transport coefficient analogous to a viscosity is given by a Kubo-type integral formula. The convergence of the integral is discussed. Some preliminary computer results are reported.

A concept for a mirror-type fusion reactor based on recent advances in neutral-beam technology is shown to have improved plasma stability, a much higher power density, and a somewhat higher factor of energy gain $Q$, as compared with previous concepts using the magnetic-mirror principle.

The velocity of first sound in liquid helium has been measured for frequencies between 5.4 and 208 kHz and at temperatures $1 \mu \mathrm{K}<|T_{\lambda }-T|<\mathrm{}5\mathrm{} \mathrm{mK}$. The dispersion $u\left(\omega \right)-u\left(0\right)\mathrm{}$ for each frequency shows a single asymmetric peak at $T_{\lambda }$. The Landau-Khalatnikov order-parameter relaxation process alone is not adequate to describe the magnitude or the shape of the dispersion. The maximum of the dispersion remains frequency dependent even at the highest frequencies.

Experimental observations of the propagation of an intense, unneutralized, annular, relativistic electron beam along a homogeneous magnetic guide field show that it is unstable. The instability is accompanied by a loss of beam particles and intense microwave emission.

A stability condition is derived for the trapped-electron instability which is valid in both the collisional and collisionless regimes. This instability arises from wave-particle interaction between the perpendicular phase velocity of the waves and the gradient-$B$ drift velocity of the electrons. The stability condition is applied to the FM-1 spherator and ST and PLT tokamaks.

All contributions to the free energy of $O\left(n\right)\mathrm{}$ and of $O\left(1\right)\mathrm{}$ are computed for an $n$-component two-dimensional Ginzburg-Landau field. The $O\left(1\right)\mathrm{}$ terms correspond to ring diagrams, and their sum constitutes the first-order screening approximation. The second derivative of the free energy with respect to temperature yields a predicted specific heat for $n=2\mathrm{}$ which peaks, in qualitative disagreement with the monotonic temperature variation found experimentally for a superconducting film by Zally and Mochel.

The elastic constants of krypton single crystals near the triple point determined from neutron-scattering measurements by Skalyo and Endoh and from our Brillouin-scattering measurements differ by as much as 12%. It is suggested that these large differences arise from the different velocities of zero and first sound.

We have studied reflection of a ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ nozzle beam from a LiF crystal surface cleaved in situ at ${10}^{-9\mathrm{}}$ Torr. As compared with previous results on water-covered surfaces, the selective adsorption intensity minima are pronouncedly sharpened and deepened and there is considerable fine structure. The main minima can be associated with three bound states and two positive-energy resonances. On aging the surface in the vacuum, the fine structure fades and the bound-state energy levels shift slightly.

Time-dependent measurements of the hot-electron magnetophonon effect in $n$-InSb have been performed with a resolution of about 10 nsec. The amplitudes and the relative importance of the two oscillation series, which involve either single LO or pairs of TA phonons, depend on the time which has passed after application of the voltage pulse. This time dependence reflects the change of average electron energy connected with the energy relaxation time and the influence of the resonant cooling process.

Synchrotron radiation is used to obtain energy distributions of photoemitted electrons from KI above and below the threshold for hole-electron pair creation by the excited electrons. Because the inelastic scattering lengths are short (≲15 Å) above the threshold and long (>100 Å) below, the energy distribution of secondary electrons due to pair creation replicates the conduction-band density of states.

The lattice instability of TmV${\mathrm{O}}_4$ near its cooperative Jahn-Teller phase transition is shown to be a competitive process involving distortions of $B_{1\mathrm{g}}$ and $B_{2\mathrm{g}}$ symmetry. In order to understand the soft-mode behavior, we must consider the spin-lattice coupling of the entire $J=6\mathrm{}$ ground multiplet of the ${\mathrm{Tm}}^{3+}$ ion. Axial magnetic fields are found to affect dramatically the soft acoustic-mode behavior.