Charged hadrons in $0.15<p_{\perp }<4\mathrm{GeV}/c$ associated with particles of $p_{\perp }^{\mathrm{trig}}>4\mathrm{GeV}/c$ are reconstructed in $pp$ and $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$. The associated multiplicity and $p_{\perp }$ magnitude sum are found to increase from $pp$ to central $\mathrm{Au}+\mathrm{Au}$ collisions. The associated $p_{\perp }$ distributions, while similar in shape on the nearside, are significantly softened on the awayside in central $\mathrm{Au}+\mathrm{Au}$ relative to $pp$ and not much harder than that of inclusive hadrons. The results, consistent with jet quenching, suggest that the awayside fragments approach equilibration with the medium traversed.

We report the present results of CUORICINO, a search for neutrinoless double-beta ($0\nu \beta \beta$) decay of ${}^{130}\mathrm{Te}$. The detector is an array of 62 ${\mathrm{TeO}}_2$ bolometers with a total active mass of 40.7 kg. The array is cooled by a dilution refrigerator shielded from environmental radioactivity and energetic neutrons, operated at $\sim 8\mathrm{mK}$ in the Gran Sasso Underground Laboratory. No evidence for ($0\nu \beta \beta$) decay was found and a new lower limit, $T_{1/2}^{0\nu }\ge 1.8\times {10}^{24}\mathrm{yr}$ (90% C.L.) is set, corresponding to $⟨m_{\nu }⟩\le 0.2$ to 1.1 eV, depending on the theoretical nuclear matrix elements used in the analysis.

We have developed a new technique to study exotic neutron-rich nuclei via their isobaric analog states (IAS). We populate high-isospin states in resonant reactions of radioactive ion beams with protons. Characteristic $\gamma$ rays emitted from excited decay products were used to identify the population of the IAS. We show that information on the differential and total cross section for formation of the IAS can be extracted from the energy spectrum of the Doppler-shifted $\gamma$ rays. This technique was applied to the study of $T=3/2$ states in ${}^7\mathrm{Li}$, which are analogs of states in ${}^7\mathrm{He}$. The analog of the ${}^7\mathrm{He}$ ground state was clearly observed, whereas the presence of the analog of a narrow $1/2^{-}$ state at 0.6 MeV excitation in ${}^7\mathrm{He}$ reported by M. Meister et al. [Phys. Rev. Lett. 88, 102501 (2002)] was excluded at the 90% confidence level. Evidence is presented for a broad $1/2^{-}$ state at a higher excitation energy in ${}^7\mathrm{He}$.

The dipole strength distribution above the one-neutron separation energy was measured in the unstable ${}^{130}\mathrm{Sn}$ and the double-magic ${}^{132}\mathrm{Sn}$ isotopes. The results were deduced from Coulomb dissociation of secondary Sn beams with energies around $500\mathrm{MeV}/\mathrm{\text{nucleon}}$, produced by in-flight fission of a primary ${}^{238}\mathrm{U}$ beam. In addition to the giant dipole resonance, a resonancelike structure (“pygmy resonance”) is observed at a lower excitation energy around 10 MeV exhausting a few percent of the isovector $E1$ energy-weighted sum rule. The results are discussed in the context of a predicted new dipole mode of excess neutrons oscillating out of phase with the core nucleons.

We report on the first measurement of elliptic flow ${\nu }_2(p_T)$ of multistrange baryons ${\Xi }^{-}+{\overline{\Xi }}^{+}$ and ${\Omega }^{-}+{\overline{\Omega }}^{+}$ in heavy-ion collisions. In minimum-bias $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$, a significant amount of elliptic flow, comparable to other nonstrange baryons, is observed for multistrange baryons which are expected to be particularly sensitive to the dynamics of the partonic stage of heavy-ion collisions. The $p_T$ dependence of ${\nu }_2$ of the multistrange baryons confirms the number of constituent quark scaling previously observed for lighter hadrons. These results support the idea that a substantial fraction of the observed collective motion is developed at the early partonic stage in ultrarelativistic nuclear collisions at the Relativistic Heavy Ion Collider.

An accurately calibrated relativistic parametrization is introduced to compute the ground state properties of finite nuclei, their linear response, and the structure of neutron stars. While similar in spirit to the successful NL3 parameter set, it produces an equation of state that is considerably softer—both for symmetric nuclear matter and for the symmetry energy. This softening appears to be required for an accurate description of several collective modes having different neutron-to-proton ratios. Among the predictions of this model are a symmetric nuclear-matter incompressibility of $K=230\mathrm{MeV}$ and a neutron skin thickness in ${}^{208}\mathrm{P}\mathrm{b}$ of $R_n-R_p=0.21\mathrm{fm}$. The impact of such a softening on various neutron-star properties is also examined.

$\alpha \mathrm{\text{−}}\gamma$ and $\alpha$-electron coincidence spectroscopy for a short-lived heavy actinide nucleus ${}^{257}\mathrm{No}$ ($T_{1/2}=24.5\mathrm{s}$) has been performed using a gas-jet transport system and an on-line isotope separator. Spin-parities of excited states in ${}^{253}\mathrm{Fm}$ fed by the $\alpha$ decay of ${}^{257}\mathrm{No}$ have been identified on the basis of the measured internal conversion coefficients. The $\nu 3/2^{+}[622]$ configuration has been assigned to the ground state of ${}^{257}\mathrm{No}$ as well as to the 124.1 keV level in ${}^{253}\mathrm{Fm}$. It was found that the ground-state configuration of ${}^{257}\mathrm{No}$ is different from that of lighter $N=155$ isotones.

The masses of the radioactive nuclei and its decay daughter have been measured with the Canadian Penning Trap on-line Penning trap mass spectrometer to a precision of . A value of 7052.90(40) keV for the superallowed beta decay of is obtained from the difference of these two masses. With this precise value, the value for this decay is determined with improved precision. An investigation of an earlier -value measurement for uncovers a set of 7 measurements that cannot be reconciled with modern data and affects previous evaluations of from superallowed Fermi decays. A new evaluation, adding our new data and removing the discredited subset, yields new values for and . When combined with recent results for , this yields modified constraints for the unitarity of the Cabibbo-Kobayashi-Maskawa matrix and other extensions of the standard model.

The Coulomb interaction between the two protons is fully included in the calculation of proton-deuteron breakup with realistic interactions for the first time. The hadron dynamics is based on the purely nucleonic charge-dependent (CD) Bonn potential and its realistic extension CD Bonn $+\Delta$ to a coupled-channel two-baryon potential, allowing for single virtual $\Delta$-isobar excitation. Calculations are done using integral equations in momentum space. The screening and renormalization approach is employed for including the Coulomb interaction. The Coulomb effect on breakup observables is seen at all energies in particular kinematic regimes.

For a Hamiltonian $H(\mathbf{q})$, given in a suitable set of basis states, we construct diabatic states from requiring conservation of their nodal structure. The diabatic states and energies are single-valued functions for an arbitrary number of parameters $\mathbf{q}\equiv \{q_1,q_2,\dots ,q_f\}$. The method is illustrated for nucleons moving in a deformed Woods-Saxon potential.

The dynamical eikonal approximation unifies the semiclassical time-dependent and eikonal methods. It allows calculating differential cross sections for elastic scattering and breakup in a quantal way by taking into account interference effects. Good agreement is obtained with experiment for ${}^{11}\mathrm{Be}$ breakup on ${}^{208}\mathrm{Pb}$. Dynamical effects are weak for elastic scattering.

We present the first measurement of pseudorapidity distribution of photons in the region $2.3\le \eta \le 3.7$ for different centralities in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=62.4\mathrm{GeV}$. We find that the photon yield scales with the number of participating nucleons at all collision centralities studied. The pseudorapidity distribution of photons, dominated by ${\pi }^0$ decays, has been compared to those of charged pions, photons, and inclusive charged particles from heavy-ion and nucleon-nucleon collisions at various energies. The photon production has been shown to be consistent with the energy and centrality independent limiting fragmentation scenario.

The nuclides ${}^{98}\mathrm{Mo}$ and ${}^{100}\mathrm{Mo}$ have been studied in photon-scattering experiments by using bremsstrahlung produced from electron beams with kinetic energies from 3.2 to 3.8 MeV. Six electromagnetic dipole transitions in ${}^{98}\mathrm{Mo}$ and 19 in ${}^{100}\mathrm{Mo}$ were observed for the first time in the energy range from 2 to 4 MeV. A specific feature in the two nuclides is the deexcitation of one state with spin $J=1$ to the $0^{+}$ ground state as well as to the first excited $0^{+}$ state, which cannot be explained in standard models. We present a model that allows us to deduce the mixing coefficients for the two $0^{+}$ shape-isomeric states from the experimental ratio of the transition strengths from the $J=1$ state to the $0^{+}$ ground state and to the $0^{+}$ excited state.

The $K^{-}p\to {\pi }^0{\pi }^0{\Sigma }^0$ reaction is studied within a chiral unitary model. The distribution of ${\pi }^0{\Sigma }^0$ states forming the $\Lambda (1405)$ shows, in agreement with a recent experiment, a peak at 1420 MeV and a relatively narrow width of $\Gamma =38\mathrm{MeV}$. The mechanism for the reaction is largely dominated by the emission of a ${\pi }^0$ prior to the $K^{-}p$ interaction leading to the $\Lambda (1405)$. This ensures the coupling of the $\Lambda (1405)$ to the $K^{-}p$ channel, thus maximizing the contribution of the second state found in chiral unitary theories, which is narrow and of higher energy than the nominal $\Lambda (1405)$. This is unlike the ${\pi }^{-}p\to K^0\pi \Sigma$ reaction, which gives more weight to the pole at lower energy and with a larger width. The data of these two experiments, together with the present theoretical analysis, provide firm evidence of the two-pole structure of the $\Lambda (1405)$.

An excellent description of both spin-independent and spin-dependent quark distributions and structure functions has been obtained with a modified Nambu—Jona-Lasinio model, which is free of unphysical thresholds for nucleon decay into quarks—hence incorporating an important aspect of confinement. We utilize this model to investigate nuclear medium modifications to structure functions and find that we are readily able to reproduce both nuclear matter saturation and the experimental $F_{2N}^A/F_{2N}$ ratio, that is, the European Muon Collaboration (EMC) effect. Applying this framework to determine $g_{1p}^A$, we find that the ratio $g_{1p}^A/g_{1p}$ differs significantly from unity, with the quenching caused by the nuclear medium being about twice that of the spin-independent case. This represents an exciting result, which, if confirmed experimentally, will reveal much about the quark structure of nuclear matter.

Dynamic supersymmetries of differential equations are defined. The case of a liquid drop with quadrupole deformation coupled to a particle with $j=3/2$ is shown as an example of a situation where the dynamic supersymmetry $OSp(5/4)$ may occur. A special solution, called $E(5/4)$, of interest in the spectroscopy of odd-even nuclei in the transitional region between spherical and gamma unstable is explicitly worked out.

Using realistic three-body wave functions corresponding to the $AV18$ interaction, it is shown that the effects of the final state interaction in the exclusive processes ${}^3\mathrm{He}(e,e^{\prime }p){}^2\mathrm{H}$ and ${}^3\mathrm{He}(e,e^{\prime }p)(pn)$, can be successfully treated in terms of a generalized eikonal approximation based upon the direct calculation of the Feynman diagrams describing the rescattering of the struck nucleon. The relevant role played by the double rescattering contribution at high values of the missing momentum is illustrated.

We report the first measurement of a ratio ${\lambda }_{{\beta }_b}/{\lambda }_{{\beta }_c}$ of bound-state (${\lambda }_{{\beta }_b}$) and continuum-state $({\lambda }_{{\beta }_c})$ ${\beta }^{-}$-decay rates for the case of bare ${}^{207}\mathrm{Tl}^{81+}$ ions. These ions were produced at the GSI fragment separator FRS by projectile fragmentation of a ${}^{208}\mathrm{Pb}$ beam. After in-flight separation with the $B\rho \mathrm{\text{−}}\Delta E\mathrm{\text{−}}B\rho$ method, they were injected into the experimental storage-ring ESR at an energy of $400.5A\mathrm{MeV}$, stored, and electron cooled. The number of both the ${}^{207}\mathrm{Tl}^{81+}$ ions and their bound-state ${\beta }^{-}$-decay daughters, hydrogenlike ${}^{207}\mathrm{Pb}^{81+}$ ions, were measured as a function of storage time by recording their Schottky-noise intensities. The experimental result, ${\lambda }_{{\beta }_b}/{\lambda }_{{\beta }_c}=0.188(18)$, is in very good agreement with the value of 0.171(1) obtained from theory employing spectra of allowed transitions.

We formulate a theory of the two-proton radioactivity based on the real-energy continuum shell model. This microscopic approach is applied to describe the two-proton decay of the $1_2^{-}$ state in ${}^{18}\mathrm{Ne}$.

Large scale shell model calculations in the valence space spanned by two major oscillator shells ($sd$ and $pf$) describe simultaneously the superdeformed excited band of ${}^{36}\mathrm{A}\mathrm{r}$ and its spherical ground state. We explain the appearance of this superdeformed band at low excitation energy as a consequence of the very large quadrupole correlation energy of the configurations with many particles and many holes ($n\mathrm{p}\mathrm{\text{−}}n\mathrm{h}$) relative to the normal filling of the spherical mean field orbits (0p-0h). We study the mechanism of mixing between the different configurations to understand why the superdeformed band survives and how it finally decays into the low-lying spherical states via the indirect mixing of the 0p-0h and 4p-4h configurations.