The g factors for the $4_1^{+}$ states in ${}_{}{}^{136}{}_{}{}^{}\mathrm{Xe}$ and ${}_{}{}^{138}{}_{}{}^{}\mathrm{Ba}$ were measured using the method of time-integral perturbed angular correlation. The levels of interest were populated by the decay of mass-separated ${}_{}{}^{136}{}_{}{}^{}\mathrm{I}$ and ${}_{}{}^{138}{}_{}{}^{}\mathrm{Cs}$. g factors of 0.80±0.15 and 0.80±0.14 were measured for the $4_1^{+}$ states in ${}_{}{}^{136}{}_{}{}^{}\mathrm{Xe}$ and ${}_{}{}^{138}{}_{}{}^{}\mathrm{Ba}$, respectively. The above results, along with those for the g factors in the $4_1^{+}$ state in ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ce}$ and the $6_1^{+}$ states in ${}_{}{}^{134}{}_{}{}^{}\mathrm{Te}$ and ${}_{}{}^{138}{}_{}{}^{}\mathrm{Ba}$, are well described by a shell-model calculation in which the effective elemental proton g factors are $g_l^{\mathcal{’}}$=1.12 and $g_s^{\mathcal{’}}$=4.12.

A γ-ray peak attributed to the deexcitation of the first excited state of ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$ has been detected from vanadium metal by a large, low background intrinsic Ge detector operating in a salt mine. The partial half-life for the electron capture decay of ${}_{}{}^{50}{}_{}{}^{}\mathrm{V}$ to the first excited state of ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$ has been estimated to be ${1.2}_{\mathrm{-}0.4}^{+0.8\mathrm{}}$×${10}^{17}$ yr. A limit on the partial half-life for ${\beta }^{\mathrm{-}}$ decay is also obtained.

The decay of ${}_{}{}^{158}{}_{}{}^{}\mathrm{Tb}$ may be a sensitive neutrino balance which could yield the electron neutrino’s mass to within a few eV. The determination of the neutrino’s mass will require a knowledge of the energy levels in ${}_{}{}^{158}{}_{}{}^{}\mathrm{Gd}$ and so we present new high precision measurements of the energies of the γ rays from the deexcitation of these levels. They are 780.166±0.007, 897.620±0.055, 944.181±0.009, 962.125±0.009, 977.070±0.170, 1107.635±0.009, and 1187.147±0.007. We also discuss the use of this neutrino balance and we review the current literature regarding the decay of ${}_{}{}^{158}{}_{}{}^{}\mathrm{Tb}$.

Sources of ${}_{}{}^{199}{}_{}{}^{}\mathrm{Po}_{}^{\mathrm{m}}{}_{}{}^{}$ and ${}_{}{}^{199}{}_{}{}^{}\mathrm{Po}_{}^{\mathrm{g}}{}_{}{}^{}$ have been produced and mass separated on line. Multiscaled spectra of γ rays, x rays, and conversion electrons, and γ-γ and γ-x-ray coincidences were measured. The M4 isomeric transition of the ${\mathrm{}(13/2)\mathrm{}}^{+}$ state of ${}_{}{}^{199}{}_{}{}^{}\mathrm{Po}$, with a half-life of 4.17 min, was observed for the first time, permitting the placement of the ${\mathrm{}(13/2)\mathrm{}}^{+}$ and ${\mathrm{}(5/2)\mathrm{}}^{\mathrm{-}}$ levels above the ${\mathrm{}(3/2)\mathrm{}}^{\mathrm{-}}$ ground state. Also, the placement of the ${\mathrm{}(13/2)\mathrm{}}^{+}$ state in Po together with previously reported α-decay Q values made possible the location of the ${\mathrm{}(13/2)\mathrm{}}^{+}$ isomeric state in ${}_{}{}^{195}{}_{}{}^{}\mathrm{Pb}$. From an analysis of γ-γ-t coincidence data and energy sums, 26 transitions were placed in a decay scheme between 23 levels in ${}_{}{}^{199}{}_{}{}^{}\mathrm{Bi}$. On the basis of systematics the population of a ${\mathrm{}(1/2)\mathrm{}}^{+}$ isomeric state in ${}_{}{}^{199}{}_{}{}^{}\mathrm{Bi}$ was deduced. The isomeric (M4) transition to the ${\mathrm{}(9/2)\mathrm{}}^{\mathrm{-}}$ ground state was not observable in the present data; its rate is at least 390 times less than the Weisskopf single particle estimate.

The directional correlation of coincident γ transitions in ${}_{}{}^{127}{}_{}{}^{}\mathrm{Te}$ has been measured following the ${\beta }^{\mathrm{-}}$ decay of ${}_{}{}^{127}{}_{}{}^{}\mathrm{Sb}$ ($T_{1/2}$=3.9 d) using Ge(Li)-Ge(Li) and Ge(Li)-NaI(T1) gamma spectrometers. Measurements have been carried out for 14 gamma cascades resulting in the determination of multipole mixing ratios δ(E2/M1) for 15 γ transitions. The present results permitted a definite spin assignment of (7/2) for the 785 keV level and confirmation of several previous assignments to other levels in ${}_{}{}^{127}{}_{}{}^{}\mathrm{Te}$. The g factor of the 340 keV (${\mathrm{}(9/2)\mathrm{}}^{\mathrm{-}}$) level has also been measured using the integral perturbed angular correlation method in the hyperfine magnetic field of a Te in Ni matrix. The results of the g factor as well as the mixing ratio for the 252 keV (${\mathrm{}(9/2)\mathrm{}}^{\mathrm{-}}$→${\mathrm{}(11/2)\mathrm{}}^{\mathrm{-}}$) transition support the earlier interpretation of this state as an anomalous coupling state.

The computed mass difference between six quark clusters formed by two neutrons and two protons is less than that (2.6 MeV) of free nucleons in both the nonrelativistic and MIT bag quark models. This is because quark-quark Coulomb and hyperfine interactions have an increased magnitude in the six-quark system. This makes a neutron-rich nucleus slightly more bound than its proton-rich mirror. The magnitude of the effect is of about the right size to account for the missing Coulomb energy problem (Nolen-Schiffer anomaly) for nuclei with A=3, 13, 17, 29, 33, and 41.

We present a microscopic treatment for the small amplitude limit of the equations of motion for the nuclear one-body density. These were derived previously by means of projection techniques, and allow for the explicit separation of mean-field and collision effects which result from the dynamics of many-body correlations. The form of the nuclear response in the presence of collision effects is derived. An illustrative application to a soluble model is discussed.

The level structure of the N=60 isotone ${}_{}{}^{99}{}_{}{}^{}\mathrm{Y}$ has been studied via the decay of ${}_{}{}^{99}{}_{}{}^{}\mathrm{Sr}$. γ singles and γ-γ coincidence measurements have resulted in 71 γ transitions placed in a decay scheme with 26 levels. γ-ray multiscaling measurements give a ${}_{}{}^{99}{}_{}{}^{}\mathrm{Sr}$ half-life of 270±10 ms. Five rotational bands, including the previously identified K=(5/2) ground-state band, have been identified in ${}_{}{}^{99}{}_{}{}^{}\mathrm{Y}$. Nilsson orbitals, with bandhead energies in keV in parentheses, associated with these five bands are (5/2)[422] (0), (5/2)[303] (487), (3/2)[301] (536), (1/2) [431] (1011), and (3/2)[431] (1119). The rotational features are consistent with an axially symmetric deformation in the range 0.3 to 0.4. The characteristics of these bands and their associated γ-ray transitions are discussed.

In the preceding paper, experimental evidence for five rotational bands in the deformed nucleus ${}_{39}{}^{99}{}_{}{}^{}\mathrm{Y}_{60}^{}{}_{}{}^{}$ was presented and discussed qualitatively. In the present paper, a quantitative analysis of these bands using the particle-rotor model is presented. One-quasiparticle calculations of level energies, single-particle E1 and M1 transitions, and collective E2 transitions provide an excellent description of the level structures and transition rates for the (5/2)[422], (5/2)[303], (3/2)[301], and (1/2)[431] bands in ${}_{}{}^{99}{}_{}{}^{}\mathrm{Y}$ and the (5/2)[422], (5/2)[303], and (3/2)[301] bands in ${}_{}{}^{103}{}_{}{}^{}\mathrm{Nb}$. The Coriolis interaction is shown to be crucial in obtaining the level energy and transition patterns of these bands. The only feature which cannot be explained by the one-quasiparticle calculations is the E1 strength from the (3/2)[431] band in ${}_{}{}^{99}{}_{}{}^{}\mathrm{Y}$.

We argue that the straightforward introduction of πN form factors into the s-wave component of the two-pion-exchange three-nucleon potential based on chiral symmetry is not free of problems. These can be avoided by means of a redefinition of the potential which considers its physical content.

The ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$(d${,}^3$He${)}^{196}$Pt reaction has been studied at $E_{\mathrm{d}}$=50 MeV. A coupled channels analysis is presented which shows that the strong excitation of the $2_2^{+}$ state, with a cross section of 80% of the $2_1^{+}$ state, cannot be explained without an important direct spectroscopic amplitude. Thus the discrepancy with the U(6‖4) supersymmetry model, in which this transition is forbidden, remains.

Direct and exchange one-step transfer mechanisms have been investigated for the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(p${,}^6$Li${)}^7$Be at $E_p$=40.3 MeV. The role of the ${}_{}{}^6{}_{}{}^{}$Li${+\mathrm{}}^6$Li clustering configuration for ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ is underlined.

Proton capture populating the ${\mathrm{}(7/2)\mathrm{}}^{\mathrm{-}}$ second-excited state in ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$, at an excitation energy of 4.57 MeV, is reported for the ${}_{}{}^6{}_{}{}^{}(\mathit{p}$,γ${)\mathrm{}}^7$Be reaction at a bombarding energy of 44.4 MeV. This state cannot be populated by either a conventional direct or semidirect process. Evidence is presented showing that this state could be populated via a multistep excitation in the entrance channel.

We have studied the absorption cross section of antiprotons on Al, Cu, and Pb for T=131.6 and 193.6 MeV. These results are compared with predictions of an optical model fitted to antiproton elastic scattering data on these nuclei and are in agreement with these predictions. The cross sections have an exponential dependence on the mass number A with an exponent of approximately 0.61.

The ${}_{}{}^{71}{}_{}{}^{}\mathrm{Ge}$ half-life has been redetermined in a series of measurements using different source preparation and counting techniques. The adopted value is 11.43±0.03 days.

We show that the information theory method of Aichelin and Huefner for calculating the fragment distribution resulting from high energy proton bombardments is an approximation to the Euler number partition. We find that a consistent application of the theory produces fragment distributions substantially steeper than the calculation of Aichelin and Huefner. The quality of fit to the data and its implications are discussed.

We present a generalization of the O(6) limit of the interacting boson model by considering an E2 transition operator which is different from the quadrupole operator used in the Hamiltonian. We analyze, both quantum mechanically and in the classical limit, under which conditions this more general O(6) limit is invariant under time reversal.

In light of a recent experiment indicating an anomalously large enhancement of the M3 moment in ${}_{}{}^{39}{}_{}{}^{}\mathrm{K}$ we examine in detail the possible mechanisms usually at play in the renormalization of magnetic moments. These include meson exchange currents, core polarization, and Δ excitations. We conclude that none of the nuclear structure mechanisms presently known are able to account for any enhancement of the M3 moment and suggest the need for a reevaluation of the experimental analysis.

The analyzing power at forward angles shows negative (positive) sign when the one-step (two-step) process is dominant. This distinguished feature has been confirmed for the unnatural-parity transition ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(p,t${)}^{206}$Pb($3^{+}$) at three proton energies 22, 35, and 50 MeV. The effect of a deuteron unbound state in the intermediate channels of the (p,d) (d,t) process is elucidated, which gives a contrary result to Pinkston and Satchler’s conjecture. The natural-parity transition (p,t)${(0\mathrm{}}^{+}$) is also interpreted consistently on the same theoretical basis.

Estimates of the mean free path of relativistic ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ in nuclear emulsion strongly suggest that it is much shorter than the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ or ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ mean free path. A discussion is given of the important implications of this difference for the interpretation of recent data on secondary helium fragments produced in interactions of relativistic primary beams.