The centrality dependence of the midrapidity charged particle multiplicity in $\mathrm{Au}+\mathrm{Au}$ heavy-ion collisions at $\sqrt{s_{NN}}=19.6$ and $200\mathrm{GeV}$ is presented. Within a simple model, the fraction of hard (scaling with number of binary collisions) to soft (scaling with number of participant pairs) interactions is consistent with a value of $x=0.13\pm 0.01\left(\mathrm{stat}\right)\pm 0.05\left(\mathrm{syst}\right)$ at both energies. The experimental results at both energies, scaled by inelastic $p\left(\overline{p}\right)+p$ collision data, agree within systematic errors. The ratio of the data was found not to depend on centrality over the studied range and yields a simple linear scale factor of $R_{200∕19.6}=2.03\pm 0.02\left(\mathrm{stat}\right)\pm 0.05\left(\mathrm{syst}\right)$.

The triaxial rotor model for nuclei is investigated by relaxing the use of irrotational moments of inertia. The dependence of observables of the model on the electric quadrupole tensor, through a triaxiality angle $\left(\gamma \right)$, and on the inertia tensor, through a mixing angle, is illustrated. This formalism provides insights into the physics of triaxial rotations in nuclei.

Neutron-production double-differential cross sections for $870\mathrm{MeV}{\pi }^{+}$ and ${\pi }^{-}$ and $2.1\mathrm{GeV}{\pi }^{+}$ mesons incident on iron and lead targets were measured with NE213 liquid scintillators by time-of-flight technique. NE213 liquid scintillators $12.7\mathrm{cm}$ in diameter and $12.7\mathrm{cm}$ thick were placed in directions of 15, 30, 60, 90, 120, and $150°$. The typical flight path length was $1.5\mathrm{m}$. Neutron detection efficiencies were evaluated by calculation results of SCINFUL and CECIL codes. The experimental results were compared with JAERI quantum molecular dynamics code. For the meson incident reactions, adoption of $NN$ in-medium effects was slightly useful for reproducing $870\mathrm{MeV}{\pi }^{+}$-incident neutron yields at neutron energies of $10–30\mathrm{MeV}$, as was the case for proton incident reactions. The ${\pi }^{-}$ incident reaction generates more neutrons than ${\pi }^{+}$ incidence as the number of nucleons in targets decrease.

A schematic model for hadronic states, based on constituent quarks and antiquarks and gluon pairs, is discussed. The phenomenological interaction between quarks and gluons is QCD motivated. The obtained hadronic spectrum leads to the identification of nucleon and $\Delta$ resonances and to pentaquark and heptaquark states. The predicted lowest pentaquark state $\left(J^{\pi }={\frac{1}{2}}^{-}\right)$ lies at the energy of $1.5\mathrm{GeV}$ and it is associated to the observed ${\Theta }^{+}\left(1540\right)$ state. For heptaquarks $\left(J^{\pi }={\frac{1}{2}}^{+},{\frac{3}{2}}^{+}\right)$ the model predicts the lowest state at $2.5\mathrm{GeV}$.

The statistical theory of particle evaporation from hot compound nuclei can be used to calculate the probability that particles are evaporated from the nuclear surface with not enough energy to surmount the Coulomb barrier. These quasievaporated particles exist between the nuclear surface and the Coulomb barrier for a short period of time before returning to the nuclear fluid. Occasionally, a quasievaporated charged particle emitted into the region surrounding the pre-scission neck material, fails to be reabsorbed by either of the main fragments as they accelerate away from each other after scission. This new particle emission mechanism can be used to explain many of the properties of ternary nuclear fission.

The nuclear incompressibility $K_{\infty }$ is deduced from measurements of the isoscalar giant monopole resonance (ISGMR) in medium-heavy nuclei, and the resulting value turns out to be model dependent. Since the considered nuclei have neutron excess, it has been suggested that the model dependence is due to the different behavior of the symmetry energy in different models. To clarify this issue, we make a systematic and careful analysis based on new Skyrme forces, which span a wide range of values for $K_{\infty }$, for the value of the symmetry energy at saturation and for its density dependence. By calculating, in a fully self-consistent fashion, the ISGMR centroid energy in ${}^{208}\mathrm{Pb}$, we reach three important conclusions: (i) the monopole energy, and consequently the deduced value of $K_{\infty }$, depend on a well-defined parameter related to the shape of the symmetry energy curve and called $K_{\mathit{sym}}$; (ii) Skyrme forces of the type of SLy4 predict $K_{\infty }$ around $230\mathrm{MeV}$, in agreement with the Gogny force (previous estimates using Skyrme interactions having been plagued by a lack of full self-consistency); (iii) it is possible to build forces which predict $K_{\infty }$ around $250\mathrm{MeV}$, although part of this increase is due to our poor knowledge of the density dependence and effective mass.

We present measurements from BNL AGS Experiment 864 of the ${}_{\Lambda }{}^3\mathrm{H}$ yield and of an upper limit on the ${}_{\Lambda }{}^4\mathrm{H}$ yield in central $11.5A\text{GeV}∕c\text{Au}+\text{Pt}$ collisions. The measurements span a rapidity range from center of mass, $y_{\mathrm{c.m.}}$, to $y_{\mathrm{c.m.}}+1$ and a transverse momentum range of $0<p_t⩽1.5\text{GeV}∕c$. We compare these results with E864 measurements of stable light nuclei and particle unstable nuclei yields of the same baryon number. The implications of these results for the coalescence of strange clusters are discussed.

We investigate the ambiguity in the choice of different gauges for a relativistic single particle model of the inclusive $(e,e^{\prime })$ reaction in the quasielastic region. Gauge ambiguities lead to different results due to the off-shellness for a bound nucleon. The difference between results using different gauges increases with energy transfer and is larger for heavier nuclei at the same incident electron energy. We compare the theoretical results with the experimental data measured at Bates, Saclay, and SLAC.

We show how the limiting fragmentation phenomenon can arise from the Color Glass Condensate model of high energy QCD. We consider the very forward rapidity region in relativistic heavy ion collisions and argue that in this region, nucleus-nucleus collisions are similar to proton-nucleus collisions (up to shadowing corrections). We then use the known results for proton-nucleus cross sections to show that it leads to the phenomenon of limiting fragmentation in the very forward region of heavy ion collisions as observed at RHIC.

The framework to describe natural phenomena at their basics being quantum mechanics, there exist a large number of common global phenomena occurring in different branches of natural sciences. One such global phenomenon is spontaneous quantum decay. However, its long time behavior is experimentally poorly known. Here we show, that by combining two genuine quantum mechanical results, it is possible to infer on this large time behavior, directly from data. Specifically, we find evidence for nonexponential behavior of alpha decay of ${}^8\mathrm{Be}$ at large times from experiments.

Projectilelike fragment emission is studied via two-particle correlation functions, constructed from coincidence data detected at very forward angles $\left(0.7°⩽{\theta }_{\mathrm{lab}}⩽7°\right)$ in the $E∕A=44$ and $77\mathrm{MeV}$ ${}^{40}\mathrm{Ar}+{}^{27}\mathrm{Al}$ reactions. The shape of the proton-proton correlation function is unexpected. Possible origins of this effect are discussed and a way to reestablish the expected shape is presented.

A numerical analysis of QED radiative corrections for elastic $e\left(\mu \right)p$ scattering in hadronic variables at energies of the current experiment at JLab is performed. The explicit formulas from the review of Akhundov et al. [Fortschr. Phys.44, 373 (1996)] resulting from the integration over the phase space of leptonic variables plus photon are used to obtain the values of the cross sections and the radiative correction factor for unpolarized lepton-proton scattering. Our numerical results agree with the corresponding results arising from the formulas of Afanasev et al. [Phys. Lett. B514, 269 (2001); Phys. Rev. D64, 113009 (2001)].

Information on $\beta$-decay properties of neutron-rich ${}^{47}\mathrm{Ar}$ was obtained at the ISOLDE facility at CERN using isobaric selectivity. This was achieved by a combination of a plasma-ion source with a cooled transfer line and subsequent mass separation. A doubly charged beam was used in order to improve the signal-to-background ratio associated with multi-charged noble gas fission products. The identification of the ${}^{47}\mathrm{Ar}$ $\gamma$-ray transitions was performed by comparing the spectra obtained from direct proton bombardment of the target and of the neutron converter. New excited levels in the daughter ${}^{47}\mathrm{K}$ nucleus corresponding to the negative-parity states were observed. The obtained data are compared to the result of large-scale shell model calculations and quasiparticle random-phase approximation predictions.

Davidson potentials of the form ${\beta }^2+{\beta }_0^4∕{\beta }^2$, when used in the E(5) framework bridge the U(5) and O(6) symmetries, while they bridge the U(5) and SU(3) symmetries when used in the X(5) framework. Using a variational procedure, we determine for each value of angular momentum $L$ the value of ${\beta }_0$ at which the rate of change of various physical quantities [energy ratios, intraband B(E2) ratios, quadrupole moment ratios] has a maximum, the collection of the values of the physical quantity formed in this way being a candidate for describing its behavior at the relevant critical point. Energy ratios lead to the E(5) and X(5) results, while intraband B(E2) ratios and quadrupole moments lead to the $\mathrm{E}\left(5\right)\text{−}{\beta }^4$ and $\mathrm{X}\left(5\right)\text{−}{\beta }^4$ models. A new derivation of the Holmberg-Lipas formula for nuclear energy spectra is obtained as a by-product.

The $\Lambda \Lambda$ bond energy $\Delta B_{\Lambda \Lambda }$ in $\Lambda \Lambda$ hypernuclei is obtained from a $G$-matrix calculation which includes the coupling between the $\Lambda \Lambda$, $\Xi N$, and $\Sigma \Sigma$ channels, as well as the effect of Pauli blocking to all orders. The Nijmegen NSC97e model is used as bare baryon-baryon interaction in the strangeness $S=-2$ sector. The $\Lambda \Lambda$-$\Xi N$ coupling increases substantially the bond energy with respect to the uncoupled $\Lambda \Lambda$ case. However, the additional incorporation of the $\Sigma \Sigma$ channel, which couples simultaneously to $\Lambda \Lambda$ and $\Xi N$ states, has a surprisingly drastic effect and reduces the bond energy down to a value closer to that obtained in an uncoupled calculation. We find that a complete treatment of Pauli blocking reduces the repulsive effect on the bond energy to about half of what was claimed before.

We derive an approximate analytic expression for thermonuclear reaction rate for charged particles for the case that the cross section contains a single narrow or broad resonance described by a Breit-Wigner shape. An asymptotic series is obtained by making a Taylor series expansion which is exact at both the effective energy of the Gamow window and at the resonance energy. The resulting expression is uniformly valid as the effective energy and resonance energy coalesce or separate and as the resonance width is varied from narrow to broad. This is not true of conventional analytic approximations. We compare our uniform approximation with the exact reaction rate numerically and find it to be accurate over a large parameter range. We use our expressions to calculate the reaction rate for ${}^{12}\mathrm{C}(p,\gamma ){}^{13}\mathrm{N}$.

The high spin structures in ${}^{86}\mathrm{Nb}$ are analyzed using the cranked Nilsson-Strutinsky model. Energy versus spin curves as well as deformations and electric transition quadrupole moments are considered. It is concluded that different single-particle parameters compared with the standard values lead to better agreement with recent experimental results.

We show that the centrality dependence of charged particle and photon pseudorapidity density at midrapidity along with the transverse energy pseudorapidity density at SPS (super proton synchrotron) and RHIC (relativistic heavy ion collider) energies scales with the number of participating constituent quarks. The number of charged particles and transverse energy per participant constituent quark is found to increase with increase in beam energy. The sensitivity of the results to change in quark-quark cross section and choice of nuclear density profile is also studied.