We try to explain the differences in the ${}^6\mathrm{He}$ dipole strength function by B. V. Danilin et al. [Phys. Rev. C $55,$ R577 (1997)] and A. Cobis, D. V. Fedorov, and A. S. Jensen [Phys. Rev. Lett. $79,$ 2411 (1997)]. We perform the full basis calculation of the strength function with the same renormalized interaction as B. V. Danilin et al. and show that the size of the basis, needed for converged calculations of the ${}^6\mathrm{He}$ continuum spectrum, is much larger than that for the discrete spectrum. The renormalized interaction of B. V. Danilin et al. therefore cannot be used for the continuum spectrum calculations with the same basis size as for the ground state.

In this reply we explain that the Comment of Fedorov, Cobis, and Jensen is misleading. First of all, there are different renormalization procedures of two-body $\alpha -n$ potentials involved in the ground state and continuum calculations of ours and the authors of the Comment. Secondly, the authors of the Comment erroneously advocate the use of effective interactions fitted for a truncated basis in calculations with extended bases.

The ${\beta }^{+}/\mathrm{EC}$ decay of a mass-separated ${}^{80}\mathrm{Y}$ source has been studied by $\beta$- and $\gamma$-ray spectroscopy following the bombardment of a thin ${}^{24}\mathrm{Mg}$ target with ${}^{58}\mathrm{Ni}$ ions at 190 MeV. An extended decay scheme with 14 new states in ${}^{80}\mathrm{Sr}$ has been identified including the first observation of negative-parity states. The low-lying positive-parity states have been found to be clustered indicating a pattern of one-, two-, and possibly three-phonon multiplets characteristic of an anharmonic vibrator. Some states in ${}^{80}\mathrm{Sr}$ can also be grouped into a $\gamma$-vibrational band. In general the low-lying states in light strontium isotopes show vibrationlike collectivity which evolves to rotational behavior with increasing spin and decreasing neutron number. The observed ${}^{80}\mathrm{Y}\beta$-decay fragmentation and $\log \mathrm{ft}$ values have also been used to assign spin and parity of $4^{-}$ and $1^{-}$ to the parent ground state and the 228.5 keV isomeric state, respectively.

High-spin states in ${}^{82}\mathrm{Rb}$ were studied through the ${}^{68}\mathrm{Zn}{(}^{18}\mathrm{O},p3n)$ reaction at 56 MeV beam energy via a thin target coincidence measurement. The known sequence of positive-parity states built on the $6^{+}$ state at 191.3 keV was extended up to spin 14, and signature inversion was observed around spin 11. Above spin 8 the observed properties of this band indicate a rotationlike structure. A new high-lying level sequence connected by $\Delta I=1\mathrm{}$ transitions was identified. This magnetic dipole sequence is built on a new ${(11\mathrm{}}^{-})$ level at 2617.3 keV excitation energy which is interpreted as a $\pi {(g}_{9/2}{)}^2\otimes \pi {(p}_{3/2}{,f}_{5/2})\otimes \nu g_{9/2}$ four-quasiparticle state at small quadrupole deformation.

Several $\mu \mathrm{s}$ isomers were observed in neutron-rich nuclei in the mass range $A=88\mathrm{}–109.$ These nuclei are produced by thermal neutron-induced fission of ${}^{241}\mathrm{Pu}.$ The detection is based on time correlation between fission fragments selected by the LOHENGRIN spectrometer, at ILL (Grenoble) and the $\gamma$-ray or conversion electron emission of the isomers. Among a dozen isomers studied, three new ones have been observed. The decay schemes of ${}^{88m}\mathrm{Br},$ ${}^{94m}\mathrm{Y},$ ${}^{96m}\mathrm{Rb},$ and ${}^{100m}\mathrm{Nb}$ are discussed in the framework of the spherical shell model. The yields and isomeric ratios of all these isomers have been measured.

Gamow-Teller (GT) transitions and $M1\mathrm{}$ transitions from or to the ground states are analogous in the pair of $T=1/2\mathrm{}$ mirror nuclei, if the excited states hold the mirror-symmetry properties. In order to study the mirror-symmetry structure of the $A=27\mathrm{}$ mirror nuclei ${}^{27}\mathrm{Al}$ and ${}^{27}\mathrm{Si},$ experimental data on GT transition strengths obtained from ${}^{27}{\overrightarrow{\mathrm{Si}}}^{27}\mathrm{Al}$ $\beta$ decay and from a good-resolution ${}^{27}\mathrm{Al}{(}^3\mathrm{He}{,t)}^{27}\mathrm{Si}$ reaction at 150 MeV/nucleon and 0° have been compared with $M1\mathrm{}$ transition strengths obtained from $\gamma$ decay in ${}^{27}\mathrm{Al}$ and ${}^{27}\mathrm{Al}(\gamma ,{\gamma }^{\prime })$ reaction. Good overall correspondence of transitions is observed for states up to nearly 9 MeV in excitation energy, where the particle-decay channel becomes important. The difference of excitation energies of analog states in the mirror nuclei are about 250 keV at this excitation energy. From a comparison of $B\left(M1\mathrm{}\right)\mathrm{}$ and $B\left(\mathrm{GT}\right)$ strengths of the analogous transitions, the contribution of the isoscalar and the orbital terms in the $M1\mathrm{}$ operator is found to become prominent in weak $M1\mathrm{}$ transitions.

We construct the equation of state (EOS) of finite nuclei including surface and Coulomb effects in a Thomas-Fermi framework using a finite range, momentum and density dependent two-body interaction. We identify critical temperatures for nuclei below which the EOS so constructed shows clear signals for liquid-gas phase transition in these finite systems. Comparison with the EOS of infinite nuclear matter shows that the critical density and temperature of the phase transition in nuclei are influenced by the mentioned finite size effects.

Few-body Glauber theory calculations of reaction cross sections for the proposed single neutron halo nucleus ${}^{19}\mathrm{C}$ are presented for an incident energy of 960 MeV/nucleon on a ${}^{12}\mathrm{C}$ target. The calculated reaction cross sections are shown to be significantly smaller than those obtained using the optical limit approximation to the Glauber theory elastic profile function. The implications of these differences upon the deduced size and structure of the extended ${}^{19}\mathrm{C}$ ground state, from newly reported interaction cross-section measurements, are discussed, including the sensitivity of the cross sections to the assumed ${}^{19}\mathrm{C}$ single neutron separation energy.

The relativistic hydrodynamical model HYLANDER-C is used to give estimates for single inclusive particle momentum spectra in $\sqrt{s}=200\mathrm{}\mathrm{G}\mathrm{e}\mathrm{V}/\mathrm{n}\mathrm{u}\mathrm{c}\mathrm{l}\mathrm{e}\mathrm{o}\mathrm{n}$ $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ collisions that will be investigated experimentally in the near future. The predictions are based on initial conditions that the initial fireball has a longitudinal extension of 1.6 fm and an initial energy density of $30.8{\mathrm{G}\mathrm{e}\mathrm{V}/\mathrm{f}\mathrm{m}}^3$ as obtained from a cascade model. For the collision energy considered here, different stopping scenarios are explored for the first time. Our calculations give particle yields of the order of 10 000 to 20 000 charged particles per event.

The electromagnetic form factors of the trinucleons ${}^3\mathrm{H}$ and ${}^3\mathrm{He}$ are calculated with wave functions obtained with the Argonne $v_{18}$ two-nucleon and Urbana IX three-nucleon interactions. Full account is taken of the two-body currents required by current conservation with the $v_{18}$ interaction as well as those associated with $N\Delta$ transition currents and the currents of Δ resonance components in the wave functions. Explicit three-nucleon current operators associated with the two-pion exchange three-nucleon interaction arising from irreducible $S$-wave pion-nucleon scattering are constructed and shown to have very little effect on the calculated magnetic form factors. The calculated magnetic form factor of ${}^3\mathrm{H},$ and charge form factors of both ${}^3\mathrm{H}$ and ${}^3\mathrm{He}$ are in satisfactory agreement with the experimental data. However, the position of the zero in the magnetic form factor of ${}^3\mathrm{He}$ is slightly underpredicted.

High precision benchmark calculations for phase shifts and mixing parameters as well as observables in elastic neutron-deuteron scattering below the deuteron breakup threshold are presented using a realistic nucleon-nucleon potential. Two totally different methods, one using a variational principle in configuration space and the other solving the Faddeev equations in momentum space, are used and compared to each other. The agreement achieved in phase shifts and mixing parameters as well as in the polarization observables is excellent. The extreme sensitivity of the vector analyzing power $A_y$ to small changes of the phase shifts and mixing parameters is pointed out.

We investigate in a model with scalar “nucleons” and mesons the contributions of higher Fock states that are neglected in the ladder approximation of the Lippmann-Schwinger equation. This leads to a breaking of covariance, both in light-front and in instant-form Hamiltonian dynamics. The lowest Fock sector neglected has two mesons in the intermediate state and corresponds to the stretched box. First we show in a simplified example that the contributions of higher Fock states are much smaller on the light-front than in instant-form dynamics. Then we show for a scattering amplitude above threshold that the stretched boxes are small, however necessary to retain covariance. For an off-energy-shell amplitude covariance is not necessarily maintained and this is confirmed by our calculations. Again, the stretched boxes are found to be small.

Based on the multiple scattering series incorporated in the Faddeev scheme the high-energy limit of the total $n+d$ cross section is evaluated in a nonrelativistic model system where spins are neglected. In contrast to the naive expectation that the total $n+d$ scattering cross section is the sum of two $\mathrm{NN}$ cross sections we find two additional effects resulting from rescattering processes. These additional terms have different signs (shadowing and antishadowing) and a different behavior as function of the energy. Our derivation of these results which are already known from Glauber theory is based on the analytical evaluation of elastic transition amplitudes in the high-energy limit. It does not depend on the diffraction-type assumptions connected with Glauber theory. In this model of spinless Yukawa type forces (with no absorption) the total $n+d$ cross section does not approach twice the $\mathrm{NN}$ total cross section in the high-energy limit but rather approaches the total $\mathrm{NN}$ cross section multiplied by a number larger than 2. Therefore, the enhancement effect resulting from rescattering is larger than the shadowing effect, which decreases faster with energy.

A new set of integral equations for the coupled $\pi \mathrm{NNN}-\mathrm{NNN}$ problem is obtained starting from the observation that this system breaks into fragments in a nontrivial way. Assuming the particles as distinguishable, there are indeed four modes of fragmentation into two clusters, while in the standard three-body problem there are three possible two-cluster partitions and conversely the four-body problem has seven different possibilities. The pion-three-nucleon collision problem is formulated through the integral-equation approach by taking into account the proper fragmentation of the system. The final result does not depend on the assumption of separability of the two-body t matrices. Then, the quasiparticle method à la Grassberger and Sandhas is applied and effective two-cluster connected-kernel equations are obtained. The corresponding bound-state problem is also formulated, and the resulting homogeneous equation provides an approach which generalizes the commonly used approaches via 3N Hamiltonians (where the meson degrees of freedom are usually suppressed) to describe the three-nucleon bound-state problem.

We investigate the nonrelativistic reduction of the Bethe-Salpeter amplitude for the deuteron electrodisintegration near threshold energies. To this end, two assumptions have been used in the calculations: (1) the static approximation and (2) the one iteration approximation. Within these assumptions it is possible to recover the nonrelativistic result including a systematic extension to relativistic corrections. We find that the so-called pair current term can be constructed from the P-wave contribution of the deuteron Bethe-Salpeter amplitude. The form factor that enters into the calculation of the pair current is constrained by the manifestly gauge independent matrix elements.

Based upon the Bonn meson-exchange-model for the nucleon-nucleon $\mathrm{}\left(\mathrm{NN}\right)\mathrm{}$ interaction, we calculate the charge-independence breaking (CIB) of the $\mathrm{NN}$ interaction due to pion-mass splitting. Besides the one-pion exchange (OPE), we take into account the $2\pi$-exchange model and contributions from three and four irreducible pion exchanges. We calculate the CIB differences in the ${}^1{S}_0$ effective range parameters as well as phase-shift differences for partial waves up to total angular momentum $J=4\mathrm{}$ and laboratory energies below 300 MeV. We find that the CIB effect from OPE dominates in all partial waves. However, the CIB effects from the $2\pi$ model are noticable up to D waves and amount to about 40% of the OPE CIB contribution in some partial waves, at 300 MeV. The effects from $3\pi$ and $4\pi$ contributions are negligible except in ${}^1{S}_0$ and ${}^3{P}_2.$

Excited states in ${}^{52}\mathrm{Fe}$ have been studied up to spin $10ħ$ in the reaction ${}^{28}\mathrm{Si}{+}^{28}\mathrm{Si}$ at 115 MeV beam energy by using in-beam $\gamma$-ray spectroscopy methods at the GASP array. The excitation energy of the yrast ${10}^{+}$ state is 7.381 MeV, almost 0.5 MeV above the well known ${\beta }^{+}$-decaying yrast ${12}^{+}$ state. Experimental upper limits for the $B\left(E4\mathrm{}\right)\mathrm{}$ transition probabilities from the ${12}^{+}$ isomer to the $8_1^{+}$ and $8_2^{+}$ states have been determined. The mean lifetimes of five excited states have been measured by using the Doppler shift attenuation method. Complete diagonalizations in the $\mathrm{pf}$ major shell lead to very good agreement with the experimental level scheme and transition probabilities. The lifetime, $\log \mathrm{ft}$ value, branching ratios, and $B\left(E4\mathrm{}\right)\mathrm{}$ values are calculated for the ${12}^{+}$ isomer. The positive parity states are also interpreted in terms of a Nilsson projected method. The structure of the yrast levels of ${}^{52}\mathrm{Fe}$ is compared with those of its cross conjugate ${}^{44}\mathrm{Ti}.$

The lifetimes of 12 states in the opposite-parity bands of ${}^{153}\mathrm{Eu}$ have been measured using a recoil-distance technique following Coulomb excitation with a 220-MeV ${}^{58}\mathrm{Ni}$ beam. Electric-quadrupole ${(Q}_0)$ and -dipole ${(D}_0)$ moments, and intrinsic g factors ${(g}_K)$ have been extracted from the lifetimes. The $Q_0$ and $D_0$ values show very little dependence on spin and parity, and have the values of approximately 6.6 e b and 0.077 e fm, respectively. The $g_K$ values are found to differ for the positive- and negative-parity states. Although the large $D_0$ values suggest a reflection-asymmetric octupole-deformed nuclear shape, the different $g_K$ values contradict this interpretation. A discussion of the nuclear structure of ${}^{153}\mathrm{Eu}$ in terms of potential parity-doublet bands and octupole deformation is given.

Angular distribution data for $\alpha$ particles emitted in the favored decay of on-line oriented neutron deficient isotopes ${}^{189,191,193}\mathrm{Bi}$ near midshell $\mathrm{}(N=104\mathrm{})\mathrm{}$ are presented. They give additional support for the recent finding that anisotropic $\alpha$ emission in favored decays from near-spherical nuclei is mainly determined by nuclear structure effects.