We calculate the neutrino and antineutrino elastic scattering cross section on unpolarized deuterons at energies from a few MeV to several GeV and squared momentum transfers up to 5 ${\mathrm{GeV}}^2$. These cross sections can be used to deduce the unknown weak SU(2) isoscalar and SU(3) flavor-scalar axial-vector coupling to nucleons. This observable can be related to the strangeness axial-vector matrix element in the absence of QCD radiative or isospin-violating corrections. We show that the unknown weak magnetic vector coupling may also be gleaned from these measurements. We use different techniques at different energies, including light-cone impulse approximation at the highest energies, and show that they connect smoothly to each other.

The problem of the imitation of CP violation in neutron scattering is discussed. The thermal motion of nuclei cannot contribute to symmetry-violating effects. The influence of the nuclear depolarization due to neutron scattering is estimated.

The decay property of ${}_{}{}^{20}{}_{}{}^{}\mathrm{Na}$ was studied using a ${}_{}{}^{20}{}_{}{}^{}\mathrm{Mg}$ beam to learn better the onset mechanism of the rapid-proton process. The delayed protons were successfully measured, which correspond to one of the possible $1^{+}$ states in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Na}$. There is no clear beta decay to the first excited $1^{+}$ state above the proton threshold, suggesting that this state would not be the s-wave resonance in the thermal reaction of ${}_{}{}^{19}{}_{}{}^{}\mathrm{Ne}$+p as was expected before. The half-life time of ${}_{}{}^{20}{}_{}{}^{}\mathrm{Mg}$ is determined to be 114±17 ms. The stellar reaction rate of ${}_{}{}^{19}{}_{}{}^{}\mathrm{Ne}$(p,γ${)}^{20}$Na is also discussed based on the present experimental result.

With the aim of studying the related phenomena of preequilibrium and statistical decay origin, light charged particles (p,d,t,α) and evaporation residues have been measured in the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$${+}^{24}$Mg reaction performed at 27.5 MeV/nucleon. Proton-residue correlations were investigated and compared to simulations based on a model associating promptly emitted particles (PEP) with binary-scission statistical decay; a satisfactory agreement is obtained. The data evidence phase-space constraints and the competing presence of (i) preequilibrium emission, which dominate at backward angles and which can be described correctly in the context of PEP, and (ii) evaporative emission focused at forward angles. The data show also a substantial complex particle emission at both preequilibrium and evaporation stages demanding their inclusion in future theoretical treatment of preequilibrium.

The observed variation of hexadecupole deformation parameter ${\mathrm{\beta }}_4$ with mass number A in rare-earth and actinide nuclei is studied in the sdg interacting boson model (IBM) using single j-shell Otsuka-Arima-Iachello mapped and IBM-2 to IBM-1 projected hexadecupole transition operator together with ${\mathrm{SU}}_{\mathit{s}\mathit{d}\mathit{g}}$(3) and ${\mathrm{SU}}_{\mathit{s}\mathit{d}\mathit{g}}$(5) coherent states. The ${\mathrm{SU}}_{\mathit{s}\mathit{d}\mathit{g}}$(3) limit is found to provide a good description of data.

Distorting effects of the target Coulomb field are exploited to learn about the time scales for projectile disintegration in heavy-ion grazing collisions at intermediate energies. A global variable that can be used for this purpose is suggested.

The cross sections for the fusion of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ with ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ are calculated at near-barrier energies. The coupling of the entrance channel to the soft giant dipole resonance in ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ is taken into account together with the coupling to the breakup channel ${}_{}{}^9{}_{}{}^{}\mathrm{Li}$+2n. The deformation of ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ is also considered. The cross section is found to exhibit important structure around the barrier.

We calculate the one-body dissipation function, appropriate for a heavy-ion collision, as a function of the size of the neck connecting the two nuclei.

We estimate the E1 and E2 contributions to the Coulomb dissociation reaction ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$+Pb→α${+}^{12}$C+Pb using semiclassical Coulomb excitation theory. For projectile energies below 300 MeV/nucleon and scattering angles greater than 1°, we find that the process is dominated by the E2 component. This is in contrast to the astrophysically interesting ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(α,γ${)}^{16}$O cross section, which is dominated by the E1 multipole at the most effective energy of 300 keV. The E2 sensitivity of Coulomb dissociation would usefully complement forthcoming ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$ β-decay data, which will constrain only the E1 component.

We have measured the spin-transfer parameters ${\mathit{K}}_{\mathit{L}\mathit{L}}$, ${\mathrm{K}}_{\mathrm{SL}}$, ${\mathit{K}}_{\mathit{L}\mathit{S}}$, and ${\mathit{K}}_{\mathit{S}\mathit{S}}$ at 635 MeV from 50° to 178° c.m. and at 485 MeV from 74° to 176° c.m. These new data have a significant impact on the phase-shift analyses. There are now sufficient data near these energies to overdetermine the elastic nucleon-nucleon amplitudes.

Inclusive and exclusive spectra of the ${\mathrm{He}}^4$(π,π′p) reaction were measured with ${\mathrm{\pi }}^{+}$ and ${\mathrm{\pi }}^{\mathrm{-}}$ at ${\mathrm{T}}_{\mathrm{\pi }}$=140 MeV and ${\mathrm{\theta }}_{\mathrm{\pi }}$=40°, and at 180 MeV and 30°, 40°, 60°, and 80° using the EPICS system at LAMPF in coincidence with eight plastic scintillators. The inclusive spectra yield cross section ratios ${\mathrm{R}}_{\mathrm{\pi }}$=σ(${\mathrm{\pi }}^{+}$)/σ(${\mathrm{\pi }}^{\mathrm{-}}$)=1.1±0.1 at both ${\mathrm{T}}_{\mathrm{\pi }}$ and all ${\mathrm{\theta }}_{\mathrm{\pi }}$. Exclusive spectra were obtained between ${\mathrm{He}}^{4\mathrm{*}}$ excitation energies ${\mathrm{E}}_{\mathrm{x}}$=21.5 and 45.0 MeV. Angular correlation functions for (π,π′p) were extracted at ${\mathrm{T}}_{\mathrm{\pi }}$=180 MeV at the four pion angles for selected regions of ${\mathrm{E}}_{\mathrm{x}}$. The (${\mathrm{\pi }}^{+}$,${\mathrm{\pi }}^{+\prime }$p) angular correlations show a distinct peak near the free proton knockout angle; however, the (${\mathrm{\pi }}^{\mathrm{-}}$,${\mathrm{\pi }}^{\mathrm{-}\prime }$p) data show either a flat distribution or a minimum near that angle. Calculations, using a distorted wave impulse approximation (DWIA) code which models the (π,π′p) reaction as a pion-included proton knockout, predict peaks in the angular correlation functions in the quasifree knockout direction and reproduce quite well the (${\mathrm{\pi }}^{+}$,${\mathrm{\pi }}^{+\prime }$p) data above ${\mathrm{E}}_{\mathrm{x}}$=30 MeV. However, these calculations do not resemble the (${\mathrm{\pi }}^{\mathrm{-}}$,${\mathrm{\pi }}^{\mathrm{-}\prime }$p) data at any excitation energy. Above ${\mathrm{E}}_{\mathrm{x}}$=30 MeV, the ratios ${\mathrm{R}}_{\mathrm{\pi }\mathrm{p}}$=σ(${\mathrm{\pi }}^{+}$,${\mathrm{\pi }}^{+\prime }$p)/σ(${\mathrm{\pi }}^{\mathrm{-}}$,${\mathrm{\pi }}^{\mathrm{-}\prime }$p) were found to be unexpectedly large (up to ${\mathrm{R}}_{\mathrm{\pi }\mathrm{p}}$=50) near the free proton knockout angle and very small (${\mathrm{R}}_{\mathrm{\pi }\mathrm{p}}$=0.3) in the opposite direction in contrast to DWIA predictions of 8 and 5, respectively. These discrepancies are evidence that strong interference occurs between the quasifree proton knockout and another process, especially in the (${\mathrm{\pi }}^{\mathrm{-}}$,${\mathrm{\pi }}^{\mathrm{-}\prime }$p) reaction. Near the ${\mathrm{He}}^4$→p+t breakup threshold, where the $2^{\mathrm{-}}$, T=0 state in ${\mathrm{He}}^4$ (${\mathrm{E}}_{\mathrm{x}}$=21.8 MeV) is known to exist, the ratio ${\mathrm{R}}_{\mathrm{\pi }\mathrm{p}}$ was found to be between 1 and 2 at all pion angles which is in reasonable agreement with the expected value of 1 for the excitation and decay of a state of good isospin.

The Tucson-Melbourne two-pion exchange three-nucleon force is split into a reducible part mediated by Δ excitation and an irreducible part not mediated by Δ excitation. The triton binding energy is calculated. The irreducible part of the Tucson-Melbourne force is taken into account in the calculation. Its reducible part is discarded, but regenerated by the explicit treatment of the Δ isobar in a coupled-channel approach. The remaining irreducible part of the Tucson-Melbourne force makes a nonnegligible contribution to the triton binding energy. The strong dependence of the triton binding energy on the cutoff parameter for the πNN vertex in the Tucson-Melbourne force is considerably reduced.

Two-pion-exchange (TPE) nucleon-nucleon potentials are derived for one or two Δ isobars in the intermediate states. Strong dynamical pair suppression is assumed. At the NNπ and the NΔπ vertices Gaussian form factors are incorporated into the relativistic two-body framework by using a dispersion representation for the one-pion-exchange amplitudes. The Fourier transformations are performed using factorization techniques for the energy denominators, taking into account the mass difference between the nucleon and the Δ isobar. Analytic expressions for the TPE potentials are obtained, which contain at most one-dimensional integrals. The TPE potentials are first calculated up to orders (${\mathit{f}}_{\mathit{N}\mathit{N}\mathrm{\pi }}$ ${\mathrm{f}}_{\mathit{N}\mathrm{\Delta }\mathrm{\pi }}$${)}^2$ and ${\mathit{f}}_{\mathit{N}\mathrm{\Delta }\mathrm{\pi }}^4$. These come from the adiabatic contributions of all planar and crossed three-dimensional momentum-space TPE diagrams. We also give the contributions of the OPE iteration, which can be subtracted or not, depending on whether one performs a coupled-channel calculation for, e.g., the NN, NΔ system, or a single NN-channel calculation. Next, we calculate the (${\mathit{m}}_{\mathrm{\pi }}$/M) corrections. These are due to the 1/M terms in the pion-nucleon vertices, and the 1/M terms in the nonadiabatic expansion of the nucleon energies in the intermediate states.

Particle-particle coincidence measurements for both large and small separation angles are reported for the reactions 140 MeV ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$${+}^{27}$Al→p-p, p-d, d-d, α-α, d-α, and p-α. Two clusters of seven detectors were used at ±50°, on both the right and left sides of the beam axis. Coincidence data were compared for nearest-neighbor and across-beam geometries. For p-p, p-d, and d-d pairs, the results of this symmetry test are consistent with independent particle evaporation. For the α-α, d-α, p-α pairs, the results indicate significant contributions from breakup of preformed fragments. These results suggest that small-angle correlations for the former pairs are useful as probes of the space-time extent of the emitters, but that the latter pairs are compromised for this task.

In ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$ interactions with nuclear emulsion at 1.52A GeV, nuclei with charge Z up to 36 have been measured as a function of the associated proton multiplicity. The data reveal the presence of a strong correlation between different types of collisions and proton multiplicities. In the study of multifragment decays, the average number of intermediate-mass fragments (3≤Z≤15) increases with the proton multiplicity, reaches a maximum 〈${\mathit{N}}_{\mathrm{IMF}}$〉=2.03 for the most violent collisions, and then decreases.

The cross section σ(θ) and analyzing power ${\mathit{A}}_{\mathit{y}}$(θ) of the ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(p→,γ${)}^4$He reaction have been measured at an incident proton energy ${\mathit{E}}_{\mathit{p}}$=2.00 MeV. The angular distribution of the spin-dependent cross section σ(θ)${\mathit{A}}_{\mathit{y}}$(θ) shows that both odd parity (E1) and even parity (E2,M1) transitions contribute to this reaction. Detailed matrix element fits result in a spin-triplet total cross section which is 0.72(+0.29,-0.18)% of the total ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(p→,γ${)}^4$He reaction cross section. A nucleon-only calculation does not reproduce the data, and predicts a spin-triplet total cross section which is only 0.01% of the total cross section. The inclusion of meson exchange currents into this calculation increases the spin-triplet cross section to 0.5% of the total cross section, in agreement with the present results. A comparison of the calculated and fitted matrix elements is presented.

Absorption of positive pions on ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ at 65 MeV has been measured with a large solid angle detector, covering also noncoplanar kinematics. Cross sections for reactions leading to little explored final states with three or four energetic nucleons (ppp,pd, and ppd) have been determined. These processes contribute about 1/3 to the total absorption cross section. Roughly 1/10 of all charged coincidence events involves the emission of a deuteron. Evidence for backward-peaked direct deuteron emission in the pd and ppd channels has been found.

Axial and planar blocking patterns in thin Si single crystals have been measured for the products of the reaction ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$(150 MeV)${+}^{28}$Si at ${\mathrm{\theta }}_{\mathit{L}}$=15° and 12°. Reaction times of the order ${10}^{\mathrm{-}18–}$${10}^{\mathrm{-}17}$ s have been observed for fusion-evaporation and fusion-fission processes.