Within a hydrodynamical approach we investigate the sensitivity of single inclusive momentum spectra of hadrons in $158A\mathrm{GeV}$ $\mathrm{Pb}+\mathrm{Pb}$ collisions to three different equations of state of nuclear matter. The initial conditions before the evolution of the fireballs and the space-time evolution pictures differ dramatically for the three equations of state when the same freeze-out temperature is used in all calculations. However, the softest of the equations of state results in transverse mass spectra that are too steep in the central rapidity region. We conclude that the transverse particle momenta are determined by the effective softness of the equation of state during the fireball expansion.

We have measured the polarization of ${}_{\Lambda }^5\mathrm{He}$ produced by the $\left({\pi }^{+}{,K}^{+}\right)$ reaction for the first time by observing the asymmetric emission of its weak decay pions. The large asymmetry parameter of the mesonic decay, which is unique to ${}_{\Lambda }^5\mathrm{He}$, made the measurement possible. The measurement is consistent with the theoretical prediction by which the mechanism of the hypernuclear polarization was clarified. This technique will open a new field to the spectroscopic study of hypernuclei.

The $\mathrm{pp}\to \mathrm{pp}{\eta }^{\prime }\left(958\right)$ reaction has been measured at the cooler synchrotron COSY at Jülich using the internal beam and the COSY-11 facility. The total cross sections at the four different excess energies $Q=1.5,1.7,2.9$, and $4.1\mathrm{MeV}$ have been evaluated to be $\sigma =2.5\mathrm{}\pm 0.5,2.9\pm 1.1,12.7\pm 3.2$, and $25.2\pm 3.6\mathrm{nb}$, respectively. In this region of excess energy the ${\eta }^{\prime }\left(958\right)$ cross sections are much lower compared to those of the ${\pi }^0$ and $\eta$ production.

Ultraviolet spectroscopy of ${}^{233}\mathrm{U}$ and ${}^{232}\mathrm{U}$, in the form of uranium oxide dissolved in 3M nitric acid, has revealed a number of spectral lines with widths of less than 6 nm from the ${}^{233}\mathrm{U}$ source but no detectable narrow lines from the ${}^{232}\mathrm{U}$ source. These lines could possibly be attributed to the decay of the ${}^{229}\mathrm{Th}$ isomeric state at an energy of around 4.0 eV.

An excited well-deformed rotational band has been observed in the $N=Z$ odd-odd nucleus ${}^{58}\mathrm{Cu}$. The first excited state in this band decays via $\gamma$ emission to the spherical states associated with the first minimum in the potential, thus providing for its unambiguous assignment to ${}^{58}\mathrm{Cu}$. In contrast, its bandhead decays via emission of a prompt 2.4(1) MeV proton to an excited state in the daughter nucleus ${}^{57}\mathrm{Ni}$. This is the first observation of proton decay from states associated with a deformed secondary minimum in the potential. Self-consistent Hartree-Fock calculations reproduce well both the large collectivity of this band and the general trend of its moment of inertia.

The recoil distance transient field technique in coincidence mode has been used to measure the magnetic moments of the ${21/2}^{+}$ and ${29/2}^{-}$ yrast states in ${}^{87}\mathrm{Nb}$. This method in conjunction with the use of five highly efficient EUROBALL cluster detectors has for the first time allowed the direct determination of individual $g$ factors of picosecond high-spin states populated in heavy-ion compound-nucleus reactions. The value $g\left({29/2}^{-}\right)=+0.56\mathrm{}\left(16\right)$ indicates that the five-quasiparticle band consists of both an aligned $g_{9/2}$ proton and a $g_{9/2}$ neutron pair besides the odd $p_{1/2}$ proton.

The cross section of the ${}^4\mathrm{He}({e,e}^{\prime }p{)}^3\mathrm{H}$ reaction has been measured for missing momenta $220\le p_m\le 690\mathrm{MeV}/c$ to study high-momentum components of the nuclear wave function and the reaction mechanism for this transition. The zero predicted in the plane-wave impulse approximation (PWIA) cross section, due to the underlying $\mathrm{pt}$ momentum distribution, is found to be washed out. Three types of calculations indicate that this is caused by final-state interactions and contributions from two-body currents. The calculations reproduce the high $p_m$ $(600–690\mathrm{MeV}/c)$ data, although due to different ingredients in the models.

An analytical relation between center of mass momenta in a nonrelativistic and a relativistic two-nucleon Schrödinger equation is proposed which allows analytically rewriting the two Schrödinger equations into each other. As a consequence a $\mathrm{NN}$ potential occurring in the relativistic Schrödinger equation can be gained from a nonrelativistic one by an analytical procedure. The $S$ matrices in the two equations are exactly identical, and therefore the two-nucleon phase shifts are also.

We report on a measurement of the ${}^{44}\mathrm{Ti}$ half-life aimed at lowering existing systematic uncertainties in this value, which is important to astrophysics. The half-life was measured by following the decay of ${}^{44}\mathrm{Ti}$ relative to ${}^{60}\mathrm{Co}$ for about 5 yr and the measurements were performed independently in three laboratories—Argonne, Jerusalem, and Torino. We suggest to combine our result, $59.0\pm 0.6$ yr, with the one from the accompanying Letter by Görres et al., $60.3\pm 1.3$ yr, to obtain a current “best value” for the half-life of ${}^{44}\mathrm{Ti}$ of $59.2\pm 0.6$ yr ( $1\sigma$ error).

Recent measurements of galactic radioactivity with the Compton Gamma Ray Observatory reported ${}^{44}\mathrm{Ti}$ activity from the supernova remnant Cassiopeia A. The absolute amount of ${}^{44}\mathrm{Ti}$ provides a stringent test for current supernova models. The main uncertainty is presently the half-life of ${}^{44}\mathrm{Ti}$. We report a new measurement of the half-life of ${}^{44}\mathrm{Ti}$ applying a novel technique using a mixed radioactive ion beam containing ${}^{44}\mathrm{Ti}$ as well as ${}^{22}\mathrm{Na}$ ions. This method allows the reliable determination of the half-life of ${}^{44}\mathrm{Ti}$ with high accuracy, $t_{1/2}=(60.3\pm 1.3)\mathrm{yr}$. The ${}^{44}\mathrm{Ti}$ abundance determined for Cassiopeia A with this half-life agrees with theoretical predictions within the observational uncertainties.

Two sets of strongly coupled rotational bands have been identified in ${}^{62}\mathrm{Zn}$. These bands have been observed up to the terminating states of their respective configurations. Lifetime measurements indicate that the transition quadrupole moments in these bands decrease as termination is approached. These results establish the first terminating states of rotational bands in the $A\sim 60$ mass region and confirm the predicted loss of collectivity associated with smooth band termination.

The quasifree $p+n\to d+\eta$ reaction cross section has been measured at the threshold using 1295 MeV protons in the CELSIUS storage ring and an internal cluster-jet deuterium target. The kinematics is chosen such that the target proton can be assumed to be a spectator. The Fermi momentum of the target neutron is used to extract the energy dependence of the cross section by reconstructing the kinematics on an event-by-event basis. The data cover excess energies from threshold to 10 MeV in the center of mass of the final $d\eta$ system. Approaching the threshold the cross section is enhanced compared to what is expected from phase space. This behavior is typical for a strong final-state interaction.

Sharp transmission resonances have been observed in the ${}_{}{}^{235}{}_{}{}^{}U(d,pf){}_{}{}^{236}{}_{}{}^{}U$ reaction. The shapes of the resonances as well as the angular distributions of the associated fission fragments are analyzed together with the data obtained previously for ${}_{}{}^{234}{}_{}{}^{}U$. The resonances are interpreted as being hyperdeformed rotational bands with ${ħ}^2/2\theta {=1.8\mathrm{}}_{-0.7\mathrm{}}^{+0.5\mathrm{}}$ and ${1.6}_{-0.4\mathrm{}}^{+1.0\mathrm{}}\mathrm{keV}$ and $K$ values of 1, 2, and 4 for ${}_{}{}^{234}{}_{}{}^{}U$ and ${}_{}{}^{236}{}_{}{}^{}U$, respectively.

A high spin isomer with spin ${25}^{-}$ and mean lifetime of $220\mu \mathrm{s}$ has been observed at an excitation energy of 4772 keV in ${}^{212}\mathrm{At}$. The measured $E3\mathrm{}$ decay rate for the 224 keV transition deexciting this level is enhanced but significantly lower than those observed in the neighboring isotopes or predicted using a multiparticle octupole coupling model. The relatively simple configurations involved in this decay and the close relationship to neighboring states allow a clear association to be made between the occupation of a specific single particle orbital and a blocking of the octupole vibrational correlation.

The $\beta$-unstable nuclei ${}^{32,34,36,38}\mathrm{Si}$ have been produced by projectile fragmentation and studied by in-beam Coulomb excitation. Excited states at $1399\pm 25$ keV and $1084\pm 20$ keV have been identified for the first time in ${}^{36}\mathrm{Si}$ and ${}^{38}\mathrm{Si}$, respectively, and tentatively assigned $J^{\pi }{=2\mathrm{}}^{+}$. The $B({E2;0\mathrm{}}_1^{+}\to 2_1^{+})$ values leading to these states and the previously identified $2_1^{+}$ states in ${}^{32,34}\mathrm{Si}$ have been measured, and are compared to shell model calculations. Our results indicate that the $2_1^{+}$ state in ${}^{34}\mathrm{Si}$ has a large $\mathrm{fp}$-shell intruder component, and that the $2_1^{+}$ states in the $N>\mathrm{}20\mathrm{}$ silicon isotopes can be reproduced assuming an $N=20\mathrm{}$ shell closure.

The weak ${\beta }^{+}$ decay of the astrophysically significant radioisotope ${}^{54}\mathrm{Mn}$ has been observed. The energies of positrons from a chemically purified ${}^{54}\mathrm{Mn}$ source were measured using the APEX spectrometer at Argonne National Laboratory. We deduce a ${\beta }^{+}$ decay branch of $(1.20\pm 0.26)\times {10}^{-9\mathrm{}}$, corresponding to a partial half-life of $(7.1\pm 1.5)\times {10}^8\mathrm{yr}$. The implications of this value for cosmic-ray confinement times are discussed in light of recent satellite measurements of the cosmic-ray abundance of ${}^{54}\mathrm{Mn}$.

We discuss an outside-inside scenario for a first order quark-hadron transition in the quark-gluon plasma (QGP) expected to be produced in heavy ion collisions, wherein the entire QGP region itself becomes like a subcritical bubble, and starts shrinking. We argue that this shrinking QGP bubble will lead to concentration of baryon number in a narrow beamlike region in the center, which can be detected by Hanbury-Brown-Twiss (HBT) analysis, or as a raised plateau in the rapidity plot of baryon number.

A phenomenological description of superdeformed bands in the Gd, Tb, and Dy isotopes is presented, based on experimental incremental alignments and the associated intruder configurations. By comparing the individual contributions of the different orbitals involved, predictions are made of $\gamma$-ray energies of 13 superdeformed bands in ${}^{145–148}\mathrm{Eu}$, ${}^{148,149}\mathrm{Tb}$, and ${}^{149,150}\mathrm{Dy}$ nuclei. Our results indicate that the incremental alignments exhibit an additivity of single-particle orbitals. The calculations also predict the occurrence of a $\Delta I=2\mathrm{}$ staggering effect in the ${}^{147,148}\mathrm{Eu}$ yrast bands.

Proton radioactivity from ${}^{141}\mathrm{Ho}$ and ${}^{131}\mathrm{Eu}$ has been identified. The ${}^{141}\mathrm{Ho}$ proton transition has an energy $E_p=1169\mathrm{}\left(8\right)\mathrm{keV}$, a half-life $t_{1/2}=4.2\mathrm{}\left(4\right)\mathrm{ms}$, and is assigned to the decay of the ${7/2}^{-}\left[523\right]$ Nilsson state. The ${}^{131}\mathrm{Eu}$ transition has an energy $E_p=950\mathrm{}\left(8\right)\mathrm{keV}$ and a half-life of 26(6) ms, consistent with decay from either the ${3/2}^{+}\left[411\right]$ or ${5/2}^{+}\left[413\right]$ Nilsson orbital. The proton decay rates deviate significantly from calculations assuming spherical configurations, and thus indicate the onset of large deformations in the region of the proton drip line below $Z=69\mathrm{}$.

We investigate fluctuations and even-odd effects in small superfluid systems at finite temperature by means of the static path approximation (SPA) plus random-phase approximation (RPA) treatment, where exact number parity projection is introduced. The RPA correction to the SPA is evaluated exactly. Results are given first for a schematic 20-level pairing model, where an excellent agreement with the exact canonical results is obtained both for even and odd systems, and then for a heavy nucleus, where the smoothing of the BCS transition and the even-odd effects in the pairing energy and specific heat are examined.