Charmonium dissociation cross sections due to flavor-exchange charmonium-baryon scattering are computed in the constituent quark model. We present results for inelastic $J/\psi N$ and ${\eta }_{c}N$ scattering amplitudes and cross sections into 46 final channels, including final states composed of various combinations of $D,D^{*},{\Sigma }_c$, and ${\Lambda }_c$. These results are relevant to experimental searches for the deconfined phase of quark matter and may be useful in identifying the contribution of initial $c\overline{c}$ production to the open-charm final states observed at the BNL Relativistic Heavy Ion Collider (RHIC) through the characteristic flavor ratios of certain channels. These results are also of interest in relation to possible charmonium-nucleon bound states.

Proposed low-energy β-beam facilities would be capable of producing intense beams of neutrinos (antineutrinos) with well-defined spectra. We present analytic expressions and numerical results that accurately show how the total neutrino flux reaching the detector depends on the geometry of the source and the detector. Several authors have proposed measurements which require using different flux shapes. We show that detectors of different sizes and shapes will receive neutrino fluxes with different spectral shapes and that the spectral shape will also be different in different regions of the same detector. Our findings also show that for certain measurements, systematic uncertainties and run time can be reduced.

In a recent paper, Aritomo discusses the possibility of forming a doubly magic superheavy nucleus using reactions with radioactive beams. I point out the suggested reactions have negligible rates.

We review a concept of the Moscow potential of the $\mathit{NN}$ interaction. On the basis of this concept, we derive by quantum inversion optical partial potentials from the modern partial-wave analysis data and deuteron properties. Point-form relativistic quantum mechanics is applied to the two-body deuteron photodisintegration. Calculations of the cross-section angular distributions cover photon energies between 1.1 and 2.5 GeV. Good agreement between our theory and recent experimental data confirms the concept of deep attractive Moscow potential with forbidden $S$ and $P$ states.

The structure of the three-body Borromean nucleus ${}^6\mathrm{He}$ is approximated by a two-body di-neutron cluster model. The binding energy of the $2n\text{−}\alpha$ system is determined to obtain a correct description of the $2n\text{−}\alpha$ coordinate, as given by a realistic three-body model calculation. The model is applied to describe the breakup effects in elastic scattering of ${}^6\mathrm{He}$ on several targets, for which experimental data exist. We show that an adequate description of the di-neutron-core degree of freedom permits a fairly accurate description of the elastic scattering of ${}^6\mathrm{He}$ on different targets.

We use a formal recurrence relation approach to multiple parton scattering to find the complete solution to the problem of medium-induced gluon emission from partons propagating in cold nuclear matter. The differential bremsstrahlung spectrum, where Landau-Pomeranchuk-Migdal destructive interference effects are fully accounted for, is calculated for three different cases: (i) a generalization of the incoherent Bertsch-Gunion solution for asymptotic on-shell jets, (ii) initial-state energy loss of incoming jets that undergo hard scattering, and (iii) final-state energy loss of jets that emerge out of a hard scatter. Our analytic solutions are given as an infinite opacity series, which represents a cluster expansion of the sequential multiple scattering. These new solutions allow, for the first time, direct comparison between initial- and final-state energy loss in cold nuclei. We demonstrate that, contrary to the naive assumption, energy loss in cold nuclear matter can be large. Numerical results to first order in opacity show that, in the limit of large jet energies, initial- and final-state energy losses exhibit different path length dependences, linear versus quadratic, in contrast to earlier findings. In addition, in this asymptotic limit, initial-state energy loss is considerably larger than final-state energy loss. These new results have significant implications for heavy-ion phenomenology in both $p+A$ and $A+A$ reactions.

A study of the level structure of ${}^{26}\mathrm{Si}$ using in-beam γ-ray spectroscopy is presented. A full level scheme is derived incorporating all states lying below the proton threshold energy. The results are in good agreement with shell model predictions and one-to-one correspondence is found with states in the mirror nucleus ${}^{26}\mathrm{Mg}$. Additionally, a γ-decay branch is observed from a state at 5677.0(17) keV, which is assigned to a $1^{+}$ resonance important in the astrophysical reaction ${}^{25}\mathrm{Al}$($p$,γ)${}^{26}\mathrm{Si}$. The newly derived resonance energy, $E_r=159.2(35)$ keV, has the effect of decreasing the reaction rate at the novae ignition temperature of $\approx 0.1$ GK by a factor of $\approx 2$ when compared with the previous most precise measurement of this state.

Within the post-form distorted wave Born approximation wherein pure Coulomb, pure nuclear and their interference terms are treated consistently in a single setup we study the beam energy dependence of the Coulomb-nuclear interference terms in the breakup of ${}^{11}\mathrm{Be}$ on a medium mass ${}^{44}\mathrm{Ti}$ target. Our results suggest that the Coulomb-nuclear interference terms are dependent on the incident beam energy and can be as big as that of the individual Coulomb or nuclear terms depending on the angle and energy of the breakup fragments. We also calculate the relative energy spectra and one-neutron removal cross sections in the breakup of ${}^{11}\mathrm{Be}$ on a heavy ${}^{208}\mathrm{Pb}$ target at 69 MeV/nucleon for two different angular ranges of the projectile center of the mass scattering angle and compare them with recently available experimental data.

We report the results of a series of measurements of the differential cross sections for inclusive pion double charge exchange in ${}^{6,7}\mathrm{Li}$, ${}^9\mathrm{Be}$, and ${}^{12}\mathrm{C}$ for positive and negative incident pions of energies 120, 180, and 240 MeV. The data are compared with the predictions of an intranuclear cascade model and a model based on two sequential single charge exchange processes.

The inclusive energy distributions of complex fragments ($3⩽9$) emitted in the reactions ${}^{20}\mathrm{Ne}$ (145, 158, 200, 218 MeV) $+$ ${}^{27}\mathrm{Al}$ have been measured in the angular range ${10}^{°}\text{−}{50}^{°}$. The fusion-fission and the deep-inelastic components of the fragment yield have been extracted using multiple Gaussian functions from the experimental fragment energy spectra. The elemental yields of the fusion-fission component have been found to be fairly well explained in the framework of the standard statistical model. It is found that strong competition occurs between the fusion-fission and the deep-inelastic processes at these energies. The time scale of the deep-inelastic process was estimated to be typically in the range of $~{10}^{-21}$–${10}^{-22}$ s, and it was found to decrease with increasing fragment mass. The angular momentum dissipations in the fully energy damped deep-inelastic process have been estimated from the average energies of the deep-inelastic components of the fragment energy spectra. The estimated angular momentum dissipations, for lighter fragments in particular, are found to be greater than those predicted by the empirical sticking limit.

We measured the β-delayed α-particle emission spectrum of ${}^{16}\mathrm{N}$ with a sensitivity for β-decay branching ratios of the order of ${10}^{-10}$. The ${}^{16}\mathrm{N}$ nuclei were produced using the $d($${}^{15}\mathrm{N}$,${}^{16}\mathrm{N}$)$p$ reaction with 70 MeV ${}^{15}\mathrm{N}$ beams and a deuterium gas target 7.5 cm long at a pressure of 1250 torr. The ${}^{16}\mathrm{N}$ nuclei were collected (over 10 s) using a thin aluminum foil with an areal density of 180 μg/cm${}^2$ tilted at $7^{°}$ with respect to the beam. The activity was transferred to the counting area by means of a stepping motor in less than $3s$ with the counting carried out over $8s$. The β-delayed α-particles were measured using a time-of-flight method to achieve a sufficiently low background. Standard calibration sources (${}^{148}\mathrm{Gd}$, ${}^{241}\mathrm{Am}$, ${}^{208,209}\mathrm{Po}$, and ${}^{227}\mathrm{Ac}$) as well as α particles and ${}^7\mathrm{Li}$ from the ${}^{10}\mathrm{B}$$(n,\alpha )$${}^7\mathrm{Li}$ reaction were used for an accurate energy calibration. The energy resolution of the catcher foil (180–220 keV) was calculated and the time-of-flight resolution (3–10 nsec) was measured using the β-delayed α-particle emission from ${}^8\mathrm{Li}$ that was produced using the $d($${}^7\mathrm{Li}$,${}^8\mathrm{Li}$)$p$ reaction with the same setup. The line shape was corrected to account for the variation in the energy and time resolution and a high statistics spectrum of the β-delayed α-particle emission of ${}^{16}\mathrm{N}$ is reported. However, our data (as well as earlier Mainz data and unpublished Seattle data) do not agree with an earlier measurement of the β-delayed α-particle emission of ${}^{16}\mathrm{N}$ taken at TRIUMF after averaging over the energy resolution of our collection system. This disagreement, among other issues, prohibits accurate inclusion of the f-wave component in the R-matrix analysis.

We reinvestigate the $J/\psi$ dissociation processes induced by the reactions with nucleons, $J/\psi +N\to {\overline{D}}^{(*)}+{\Lambda }_c$, in the meson-exchange model. Main constraints used in this work are vector-meson dominance and charm vector-current conservation. We show that the cross section for $J/\psi +N\to \overline{D}+{\Lambda }_c$ can be larger than that for $J/\psi +N\to {\overline{D}}^{*}+{\Lambda }_c$ when these constraints are imposed. The dependence of the cross sections on the coupling constants is analyzed in detail, and the comparison with the recent quark-interchange model predictions is also made.

The centrality and system size dependence of multiplicity fluctuations of charged particles produced in nuclear collisions at $158A$ GeV was studied by the NA49 Collaboration. Centrality selected Pb+Pb collisions, semicentral C+C and Si+Si collisions as well as inelastic $p$+$p$ interactions were analyzed. The number of projectile participants determined on an event-by-event basis was used to characterize the collision centrality. The scaled variance of the multiplicity distribution obtained in the forward rapidity region ($1.1<y_{\mathrm{c.m.}}<2.6$) shows a significant increase toward peripheral collisions. The results are similar for negatively and positively charged particles and about 50% larger for all charged particles. String-hadronic models of nuclear reactions without the fusion process do not reproduce the rise of fluctuations from central toward peripheral collisions. The measured centrality dependence can be reproduced in superposition models with the assumption of contributions from target participants to particle production in the forward hemisphere or in string models with fusion.

We explore the mechanism of transverse momentum broadening of fast quarks propagating in nuclei, using Drell-Yan (DY) transverse momentum distributions measured in experiment E866 at the Fermi National Accelerator Laboratory with beams of 800 GeV protons. Our theoretical analysis is based on the color-dipole approach in the target rest frame, which has provided a successful phenomenological description of a variety of hadronic reactions. The present application is relevant to the regime of short coherence length, where the spatial extent of the fluctuations of the projectile responsible for the Drell-Yan reaction is short compared to the internucleon spacing. In this limit, momentum broadening comes from initial state interactions and is described as color filtering, i.e., the absorption of large-size dipoles leading to diminished transverse separation and hence enhanced transverse momentum. The predictions we present are in good agreement with the E866 data. The interactions leading to the acquisition of transverse momentum arise from the color-dipole cross section determined previously from deep-inelastic scattering on proton targets. Aside from the determination of the color-dipole cross section, no other phenomenological input is needed to explain the experimental results. The mean-square momentum broadening of dileptons determined in a recent separate analysis of the data is likewise well described by our theory. These results confirm within the model studied that the origin of momentum broadening in DY is the color-dipole cross section mediating the soft initial state interactions between the parton of the projectile that initiates the reaction and the nucleons of the nucleus, as provided by the color-dipole description. Predictions for broadening observables at the BNL Relativistic Heavy Ion Collider are presented.

A newly-proposed parity-violating nucleon-nucleon interaction based on effective field theory is studied in this work. Using the hybrid effective field theory treatment, it is found that the parity-violating phenomena at low energy, where $S\text{−}P$ transitions dominate, can be well specified by a set of six parameters. This includes five low-energy constants, which are equivalent to the Danilov parameters, and an additional parameter that characterizes the long-range one-pion exchange and is proportional to the parity-violating pion-nucleon coupling constant $h_{\pi }^1$. Selected observables in two-nucleon systems are analyzed, with their dependences on these parameters being determined by employing high-quality wave functions.

The masses of neutron-rich ${}^{106-112}\mathrm{Tc}$, ${}^{106-115}\mathrm{Ru}$, ${}^{108-118}\mathrm{Rh}$, and ${}^{112-120}\mathrm{Pd}$ produced in proton-induced fission of uranium were determined using the JYFLTRAP double Penning trap setup. The measured isotopic chains include a number of previously unmeasured nuclei. Typical precisions on the order of 10 keV or better were achieved, representing a factor of 10 improvement over earlier data. In many cases, significant deviations from the earlier measurements were found. The obtained data set of 39 masses is compared with different mass predictions and analyzed for global trends in the nuclear structure.

By means of HFB calculations with independent constraints on axial neutron and proton quadrupole moments ${\widehat{Q}}_n$ and ${\widehat{Q}}_p$, we investigate the large amplitude isoscalar and isovector deformation properties of the neutron-rich isotope ${}^{20}\mathrm{O}$. Using the particle-number and angular-momentum projected generator coordinate method, we analyze the collective dynamics in the $\{\langle {\widehat{Q}}_n\rangle ,\langle {\widehat{Q}}_p\rangle \}$ plane. The parametrization SLy4 of the Skyrme interaction is used for all calculations in connection with a density-dependent zero-range pairing interaction. Our results show that already for this moderately neutron-rich nucleus the transition moments are modified when independent neutron and proton collective dynamics are allowed.

We apply the algebraic Bethe ansatz technique to the nuclear pairing problem with orbit dependent coupling constants and degenerate single particle energy levels. We find the exact energies and eigenstates. We show that for a given shell, there are degeneracies between the states corresponding to less than and more than half full shell. We also provide a technique to solve the equations of Bethe ansatz.

For each of the (9/2), (11/2), and (13/2) single $j$ shells we have only one state with $J=j$ $v=3$ for a five particle system. For four identical particles there can be more than one state of seniority four. We note some “ratio” relations for the coefficients of fractional parentage for the four and five identical particle systems, which are found in the works of de Shalit and Talmi [Nuclear Shell Theory (Academic Press, New York, 1963)] and Talmi [Simple Models of Complex Nuclei (Harwood Academic, Reading, UK, 1993)] to be useful for explaining the vanishing of a five particle coefficients of fractional parentage (cfp). These relations are used to show that there is a special $(g_{9/2}){}^{4}I=4v=4$ wave function that cannot be admixed with an $I=4v=2$ wave function, even with seniority violating interactions.

The quasielastic excitation function at ${\theta }_{\mathrm{lab}}=161°$ has been measured for the ${}^{16}\mathrm{O}$+${}^{64}\mathrm{Zn}$ system at energies near the Coulomb barrier. Coupled-channel calculations were compared with the deduced quasielastic barrier distribution and with data sets available in the literature for this system, such as fusion, elastic, and inelastic scattering. Using the double-folding São Paulo potential as the bare nuclear interaction of this system, the free-parameter calculations present good and simultaneous prescriptions for all reaction channels analyzed, except for fusion. A striking collectivity of the ${}^{64}\mathrm{Zn}$ target nucleus is revealed by the strong coupling effects of its quadrupole and octupole vibrations on the fusion, elastic, and inelastic cross sections.