We introduce a cumulant expansion to parametrize possible initial conditions in relativistic heavy ion collisions. We show that the cumulant expansion converges and that it can systematically reproduce the results of Glauber type initial conditions. At third order in the gradient expansion the cumulants characterize the triangularity $\langle r^3\cos 3(\varphi -{\psi }_{3,3})\rangle$ and the dipole asymmetry $\langle r^3\cos (\varphi -{\psi }_{1,3})\rangle$ of the initial entropy distribution. We show that for midperipheral collisions the orientation angle of the dipole asymmetry ${\psi }_{1,3}$ has a $20\%$ preference out of plane. This leads to a small net $v_1$ out of plane. In peripheral and midcentral collisions the orientation angles ${\psi }_{1,3}$ and ${\psi }_{3,3}$ are strongly correlated, but this correlation disappears towards central collisions. We study the ideal hydrodynamic response to these cumulants and determine the associated $v_1/{\epsilon }_1$ and $v_3/{\epsilon }_3$ for a massless ideal gas equation of state. The space time development of $v_1$ and $v_3$ is clarified with figures. These figures show that $v_1$ and $v_3$ develop toward the edge of the nucleus, and consequently the final spectra are more sensitive to the viscous dynamics of freezeout. The hydrodynamic calculations for $v_3$ are provisionally compared to Alver and Roland fit of STAR inclusive two-particle correlation functions. Finally, we propose to measure the $v_1$ associated with the dipole asymmetry and the correlations between ${\psi }_{1,3}$ and ${\psi }_{3,3}$ by measuring a two-particle correlation with respect to the participant plane $\langle \cos ({\varphi }_{\alpha }-3{\varphi }_{\beta }+2{\Psi }_{\mathit{PP}})\rangle$. The hydrodynamic prediction for this correlation function is several times larger than a correlation currently measured by the STAR collaboration $\langle \cos ({\varphi }_{\alpha }+{\varphi }_{\beta }-2{\Psi }_{\mathit{PP}})\rangle$. This experimental measurement would provide convincing evidence for the hydrodynamic and geometric interpretation of two-particle correlations at RHIC.

The STAR Collaboration at the BNL Relativistic Heavy Ion Collider has measured two-pion correlation functions from $p+p$ collisions at $\sqrt{s}=200$ GeV. Spatial scales are extracted via a femtoscopic analysis of the correlations, though this analysis is complicated by the presence of strong nonfemtoscopic effects. Our results are put into the context of the world data set of femtoscopy in hadron-hadron collisions. We present the first direct comparison of femtoscopy in $p+p$ and heavy ion collisions, under identical analysis and detector conditions.

We calculate the statistical significance of the anomalous deficit of electron neutrinos measured in the radioactive source experiments of the GALLEX and SAGE solar neutrino detectors, taking into account the uncertainty of the detection cross section. We found that the statistical significance of the anomaly is $~$$3.0\sigma$. A fit of the data in terms of neutrino oscillations favors at $~$$2.7\sigma$ short-baseline electron neutrino disappearance with respect to the null hypothesis of no oscillations.

The nuclear mean-field potentials obtained in the Hartree-Fock method with different choices of the in-medium nucleon-nucleon (NN) interaction have been used to study the equation of state (EOS) of the neutron star (NS) matter. The EOS of the uniform NS core has been calculated for the $\mathit{npe}\mu$ composition in the $\beta$ equilibrium at zero temperature, using version Sly4 of the Skyrme interaction as well as two density-dependent versions of the finite-range M3Y interaction (CDM3Y$n$ and M3Y-P$n$), and versions D1S and D1N of the Gogny interaction. Although the considered effective NN interactions were proven to be quite realistic in numerous nuclear structure and/or reaction studies, they give quite different behaviors of the symmetry energy of nuclear matter at supranuclear densities that lead to the soft and stiff scenarios discussed recently in the literature. Different EOS’s of the NS core and the EOS of the NS crust given by the compressible liquid drop model have been used as input of the Tolman-Oppenheimer-Volkov equations to study how the nuclear symmetry energy affects the model prediction of different NS properties, like the cooling process as well as the gravitational mass, radius, and moment of inertia.

We have calculated the zero-temperature properties of the outer crust of neutron stars for four nuclear-mass models based on the Hartree-Fock-Bogoliubov method: the three most recent Skyrme-force models (HFB-19, HFB-20, and HFB-21) and the Gogny-force model D1M. While the equation of state is substantially the same for the four models, the nuclidic composition varies considerably from one model to another. We solve the Tolman-Oppenheimer-Volkoff equations by integrating inward from the surface and thereby determine the abundance of each nuclide in the outer crust of a typical neutron star of mass $1.5M_{\odot }$ and radius 13 km. Although the total mass of the outer crust is slightly model dependent, its thickness is essentially the same for all four models.

The impulse approximation of pion production reactions is studied by developing a relativistic formalism, consistent with that used to define the nucleon-nucleon potential. For plane wave initial states we find that the usual one-body (1B) expression ${\mathcal{O}}_{1\mathrm{B}}$ is replaced by ${\mathcal{O}}_{2\mathrm{B}}=-\mathit{iK}(m_{\pi }/2){\mathcal{O}}_{1\mathrm{B}}/m_{\pi }$, where $K(m_{\pi }/2)$ is the sum of all irreducible contributions to nucleon-nucleon scattering with energy transfer of $m_{\pi }/2$. We show that ${\mathcal{O}}_{2\mathrm{B}}\approx {\mathcal{O}}_{1\mathrm{B}}$ for plane wave initial states. For distorted waves, we find that the usual operator is replaced with a sum of two-body operators that are well approximated by the operator ${\mathcal{O}}_{2\mathrm{B}}$. Our new formalism solves the (previously ignored) problem of energy transfer forbidding a one-body impulse operator. Using a purely one pion exchange deuteron, the net result is that the impulse amplitude for $\mathit{np}\to d{\pi }^0$ at threshold is enhanced by a factor of approximately two. This amplitude is added to the larger “rescattering” amplitude and, although experimental data remain in disagreement, the theoretical prediction of the threshold cross section is brought closer to (and in agreement with) the data.

A coherent state technique is used to generate an interacting boson model (IBM) Hamiltonian energy surface which is adjusted to match a mean-field energy surface. This technique allows the calculation of IBM Hamiltonian parameters, prediction of properties of low-lying collective states, as well as the generation of probability distributions of various shapes in the ground state of transitional nuclei, the last two of which are of astrophysical interest. The results for krypton, molybdenum, palladium, cadmium, gadolinium, dysprosium, and erbium nuclei are compared with experiment.

The analysis of the recent experimental data on charged-current neutrino-nucleus scattering cross sections measured at MiniBooNE requires relativistic theoretical descriptions also accounting for the role of final-state interactions. In this work we evaluate inclusive quasielastic differential neutrino cross sections within the framework of the relativistic impulse approximation. Results based on the relativistic mean-field potential are compared with the ones corresponding to the relativistic Green's-function approach. An analysis of scaling and superscaling properties provided by both models is also presented.

Nucleon drift and diffusion mechanisms in central collisions of asymmetric heavy ions at near-barrier energies are investigated in the framework of a stochastic mean-field approach. Expressions for diffusion and drift coefficients for nucleon transfer deduced from the stochastic mean-field approach in the semiclassical approximation have similar forms familiar from the phenomenological nucleon exchange model. The variance of fragment mass distribution agrees with the empirical formula ${\sigma }_{\mathrm{AA}}^2(t)=N_{\mathrm{exc}}(t)$. The comparison with the time-dependent Hartree-Fock calculations shows that below barrier energies, the drift coefficient in the semiclassical approximation underestimates the mean number of nucleon transfer obtained in the quantal framework. Motion of the window in the dinuclear system has a significant effect on the nucleon transfer in asymmetric collisions.

The dynamics of pions and strange particles in heavy-ion collisions in the region of $1A$ GeV energies is investigated by the lanzhou quantum molecular dynamics model for probing the nuclear equation of state at suprasaturation densities. The total multiplicities and the ratios obtained in ${}^{197}\mathrm{Au}$${+}^{197}$Au over ${}^{12}\mathrm{C}$${+}^{12}$C systems are calculated for selected Skyrme parameters SkP, SLy6, Ska, and SIII, which correspond to different modulus of incompressibility of symmetric nuclear matter and different cases of the stiffness of symmetry energy. A decreasing trend of the excitation functions of the ratios for strange particle production with increasing incident energy was observed. The available data of ${\mathrm{K}}^{+}$ production measured by KaoS collaboration are described well with the parameter SkP, which results in a soft equation of state. The conclusions cannot be modified by an in-medium kaon-nucleon potential.

Prompt fission neutrons following the thermal and 0.5 MeV neutron-induced fission reaction of ${}^{239}\mathrm{Pu}$ are calculated using a Monte Carlo approach to the evaporation of the excited fission fragments. Exclusive data such as the multiplicity distribution $P(\nu )$, the average multiplicity as a function of fragment mass $\mathrm{\nu ̄}(A)$, and many others are inferred in addition to the most used average prompt fission neutron spectrum $\chi (E_{\text{in}},E_{\text{out}})$, as well as average neutron multiplicity $\mathrm{\nu ̄}$. Experimental information on these more exclusive data help constrain the Monte Carlo model parameters. The calculated average total neutron multiplicity is ${\mathrm{\nu ̄}}_c=2.871$ in very close agreement with the evaluated value ${\mathrm{\nu ̄}}_e=2.8725$ present in the ENDF/B-VII.0 library. The neutron multiplicity distribution $P(\nu )$ is in very good agreement with the evaluation by Holden and Zucker. The calculated average spectrum differs in shape from the ENDF/B-VII.0 spectrum, evaluated with the Madland-Nix model. In particular, we predict more neutrons in the low-energy tail of the spectrum (below about 300 keV) than the Madland-Nix calculations, casting some doubts on how much scission neutrons contribute to the shape of the low-energy tail of the spectrum. The spectrum high-energy tail is very sensitive to the total kinetic energy distribution of the fragments as well as to the total excitation energy sharing at scission. Present experimental uncertainties on measured spectra above 6 MeV are too large to distinguish between various theoretical hypotheses. Finally, comparisons of the Monte Carlo results with experimental data on $\mathrm{\nu ̄}(A)$ indicate that more neutrons are emitted from the light fragments than the heavy ones, in agreement with previous works.

Mass and energy distributions of binary reaction products obtained in the reactions ${}^{22}\mathrm{Ne}$$+$${}^{249}\mathrm{Cf}$,${}^{26}\mathrm{Mg}$$+$${}^{248}\mathrm{Cm}$, ${}^{36}\mathrm{S}$$+$${}^{238}\mathrm{U}$, and ${}^{58}\mathrm{Fe}$$+$${}^{208}\mathrm{Pb}$ have been measured. All reactions lead to Hs isotopes. At energies below the Coulomb barrier the bimodal fission of Hs${}^{*}$, formed in the reaction ${}^{26}\mathrm{Mg}$$+$${}^{248}\mathrm{Cm}$, is observed. In the reaction ${}^{36}\mathrm{S}$$+$${}^{238}\mathrm{U}$, leading to the formation of a similar compound nucleus, the main part of the symmetric fragments arises from the quasifission process. At energies above the Coulomb barrier fusion-fission is the main process leading to the formation of symmetric fragments for both reactions with Mg and S ions. In the case of the ${}^{58}\mathrm{Fe}$$+$${}^{208}\mathrm{Pb}$ reaction the quasifission process dominates at all measured energies.

Transverse momentum distributions and yields for ${\pi }^{\pm }$, $K^{\pm }$, $p$, and $\mathrm{p̄}$ in $p+p$ collisions at $\sqrt{s}$ $=$ 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). These data provide important baseline spectra for comparisons with identified particle spectra in heavy ion collisions at RHIC. We present the inverse slope parameter $T_{\mathrm{inv}}$, mean transverse momentum $\langle p_T\rangle$, and yield per unit rapidity $\mathit{dN}/\mathit{dy}$ at each energy, and compare them to other measurements at different $\sqrt{s}$ in $p+p$ and $p+\mathrm{p̄}$ collisions. We also present the scaling properties such as $m_T$ scaling and $x_T$ scaling on the $p_T$ spectra between different energies. To discuss the mechanism of the particle production in $p+p$ collisions, the measured spectra are compared to next-to-leading-order or next-to-leading-logarithmic perturbative quantum chromodynamics calculations.

We perform a calculation for the three-body $N\mathrm{K̄}K$ scattering amplitude by using the fixed-center approximation to the Faddeev equations, taking the interaction between $N$ and $\mathrm{K̄}$, $N$ and $K$, and $\mathrm{K̄}$ and $K$ from the chiral unitary approach. The resonant structures show up in the modulus squared of the three-body scattering amplitude and suggest that a $N\mathrm{K̄}K$ hadron state can be formed. Our results are in agreement with others obtained in previous theoretical works, which claim a new $N^{*}$ resonance around $1920$ MeV with spin-parity $J^P=1/2^{+}$. The existence of these previous works allows us to test the accuracy of the fixed center approximation in the present problem and sets the grounds for possible application in similar problems, as an explorative tool to determine bound or quasibound three-hadron systems.

The elastic scattering cross sections for the reactions ${}^{110,116}\mathrm{Cd}$($\alpha ,\alpha$)${}^{110,116}\mathrm{Cd}$ at energies above and below the Coulomb barrier are presented to provide a sensitive test for the $\alpha$-nucleus optical potential parameter sets. Additional constraints for the optical potential are taken from the analysis of elastic scattering excitation functions at backward angles which are available in literature. Moreover, the variation of the elastic $\alpha$ scattering cross sections along the $Z=48$ isotopic and $N=62$ isotonic chain is investigated by the study of the ratios of the ${}^{106,110,116}\mathrm{Cd}$($\alpha ,\alpha$)${}^{106,110,116}\mathrm{Cd}$ scattering cross sections at $E_{\mathrm{cm}}\approx 15.6\text{and}18.8$ MeV and the ratio of the ${}^{110}\mathrm{Cd}$($\alpha ,\alpha$)${}^{110}\mathrm{Cd}$ and ${}^{112}\mathrm{Sn}$($\alpha ,\alpha$)${}^{112}\mathrm{Sn}$ reaction cross sections at $E_{\mathrm{cm}}\approx 18.8$ MeV, respectively. These ratios are sensitive probes for the $\alpha$-nucleus optical potential parametrizations. The potentials under study are a basic prerequisite for the prediction of $\alpha$-induced reaction cross sections (e.g., for the calculation of stellar reaction rates in the astrophysical $p$ or $\gamma$ process).

We generate a second equation of state (EOS) of nuclear matter for a wide range of temperatures, densities, and proton fractions for use in supernovae, neutron star mergers, and black hole formation simulations. We employ full relativistic mean field (RMF) calculations for matter at intermediate density and high density, and the virial expansion of a nonideal gas for matter at low density. For this EOS we use the RMF effective interaction FSUGold, whereas our earlier EOS was based on the RMF effective interaction NL3. The FSUGold interaction has a lower pressure at high densities compared to the NL3 interaction. We calculate the resulting EOS at over 100 000 grid points in the temperature range $T=0$ to 80 MeV, the density range $n_B={10}^{-8}$ to 1.6 fm${}^{-3}$, and the proton fraction range $Y_p=0$ to 0.56. We then interpolate these data points using a suitable scheme to generate a thermodynamically consistent equation of state table on a finer grid. We discuss differences between this EOS, our NL3-based EOS, and previous EOSs by Lattimer-Swesty and H. Shen et al. for the thermodynamic properties, composition, and neutron star structure. The original FSUGold interaction produces an EOS, which we call FSU1.7, that has a maximum neutron star mass of 1.7 solar masses. A modification in the high-density EOS is introduced to increase the maximum neutron star mass to 2.1 solar masses and results in a slightly different EOS that we call FSU2.1. The EOS tables for FSU1.7 and FSU2.1 are available for download.

We investigate the influence of deformation on the possible occurrence of long-lived $K$ isomers in Hf isotopes around $N=116$, using configuration-constrained calculations of potential-energy surfaces. Despite having reduced shape elongation, the multiquasiparticle states in ${}^{186,188}\mathrm{Hf}$ remain moderately robust against triaxial distortion, supporting the long expected occurrence of exceptionally long-lived isomers. The calculations are compared with available experimental data.

We derive the total and the differential cross sections with respect to angle for neutron-induced reactions from an analytical model having a simple functional form to demonstrate the quantitative agreement with the measured cross sections. The energy dependence of the neutron-nucleus interaction cross sections are estimated successfully for energies ranging from 5 to 600 MeV. In this work, the effect of the imaginary part of the nuclear potential is treated more appropriately compared to our earlier work. The angular distributions for neutron scattering also agree reasonably well with the experimental data at forward angles.

In this paper, we investigate the influence of nuclear effects in the production of gluinos in nuclear collisions at the Large Hadron Collider, and estimate the transverse momentum dependence of the nuclear ratios $R_{\mathit{pA}}=\frac{d\sigma (\mathit{pA})}{\mathit{dy}{d}^2{p}_T}/A\frac{d\sigma (\mathit{pp})}{\mathit{dy}{d}^2{p}_T}$ and $R_{\mathit{AA}}=\frac{d\sigma (\mathit{AA})}{\mathit{dy}{d}^2{p}_T}/A^2\frac{d\sigma (\mathit{pp})}{\mathit{dy}{d}^2{p}_T}$. We demonstrate that depending on the magnitude of the nuclear effects, the production of gluinos could be enhanced, compared to proton-proton collisions. The study of these observables can be useful to determine the magnitude of the shadowing and antishadowing effects in the nuclear gluon distribution. Moreover, we test different snowmass points and slopes scenarios, corresponding to different soft, supersymmetry breaking mechanisms, and find that the nuclear ratios are strongly dependent on that choice.

We present a unified Dyson-Schwinger equation treatment of static and electromagnetic properties of pseudoscalar and vector mesons, and scalar and axial-vector diquark correlations, based upon a vector-vector contact interaction. A basic motivation for this paper is the need to document a comparison between the electromagnetic form factors of mesons and those diquarks that play a material role in nucleon structure. A notable result, therefore, is the large degree of similarity between related meson and diquark form factors. The simplicity of the interaction enables computation of the form factors at arbitrarily large spacelike $Q^2$, which enables us to expose a zero in the $\rho$-meson electric form factor at $z_Q^{\rho }\approx \surd 6m_{\rho }$. Notably, $r_{\rho }{z}_Q^{\rho }\approx r_D{z}_Q^D$, where $r_{\rho }$ and $r_D$ are, respectively, the electric radii of the $\rho$-meson and deuteron.