The hadron string dynamics (HSD) model is generalized to include the creation and evolution of retarded electromagnetic fields as well as the influence of the magnetic and electric fields on the quasiparticle propagation. The time-space structure of the fields is analyzed in detail for noncentral Au $+$ Au collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV. It is shown that the created magnetic field is highly inhomogeneous, but in the central region of the overlapping nuclei it changes relatively weakly in the transverse direction. For the impact parameter $b=10$ fm, the maximal magnetic field— perpendicularly to the reaction plane—is obtained of order ${\mathit{eB}}_y/m_{\pi }^2~$5 for a very short time $~$0.2 fm/$c$, which roughly corresponds to the time of a maximal overlap of the colliding nuclei. We find that at any time, the location of the maximum in the ${\mathit{eB}}_y$ distribution correlates with that of the energy density of the created particles. In contrast, the electric field distribution, being also highly inhomogeneous, has a minimum in the center of the overlap region. Furthermore, the field characteristics are presented as a function of the collision energy and the centrality of the collisions. To explore the effect of the back reaction of the fields on hadronic observables, a comparison of HSD results with and without fields is exemplified. Our actual calculations show no noticeable influence of the electromagnetic fields—created in heavy-ion collisions—on the effect of the electric charge separation with respect to the reaction plane.

The complete expression for the intensity in pseudo-scalar meson photoproduction with a polarized beam, target, and recoil baryon is derived using a density matrix approach that offers great economy of notation. A Cartesian basis with spins for all particles quantized along a single direction, the longitudinal beam direction, is used for consistency and clarity in interpretation. A single spin-quantization axis for all particles enables the amplitudes to be written in a manifestly covariant fashion with simple relations to those of the well-known Chew-Goldberger-Low-Nambu formalism. Possible sign discrepancies between theoretical amplitude-level expressions and experimentally measurable intensity profiles are dealt with carefully. Our motivation is to provide a coherent framework for coupled-channel partial-wave analysis of several meson photoproduction reactions, incorporating recently published and forthcoming polarization data from Jefferson Lab.

The substantial contribution of neutron pickup to proton elastic scattering from ${}^8\mathrm{He}$ is modified by breakup of the outgoing deuteron. We draw attention to the fact that certain relevant quantitative results given in Mackintosh and Keeley [Phys. Rev. C 81, 034612 (2010)] require amendment in light of what we have subsequently found in the course of later work [N. Keeley and R. S. Mackintosh, Phys. Rev. C 83, 044608 (2011)]. We also add some results and comment on the need for verification, by an alternative formalism, of the effects found.

It is shown that the recently developed hybrid code VISHNU, which couples a relativistic viscous fluid dynamical description of the quark-gluon plasma (QGP) with a microscopic Boltzmann cascade for the late hadronic rescattering stage, yields an excellent description of charged and identified hadron spectra and elliptic flow measured in 200 $A$ GeV $\text{Au}+\text{Au}$ collisions at the Relativistic Heavy-Ion Collider (RHIC). Using initial conditions that incorporate event-by-event fluctuations in the initial shape and orientation of the collision fireball and values $\eta /s$ for the specific shear viscosity of the quark-gluon plasma that were recently extracted from the measured centrality dependence of the eccentricity-scaled, $p_T$-integrated charged hadron elliptic flow $v_{2,\mathrm{ch}}/\varepsilon$, we obtain universally good agreement between theory and experiment for the $p_T$ spectra and differential elliptic flow $v_2(p_T)$ for both pions and protons at all collision centralities.

To solve the current debate on the position of the quasibound $K^{-}p$ state, namely, “$\Lambda (1405)$ or $\Lambda {}^{*}(1420),$” we propose to measure the $T_{21}=T_{\Sigma \pi \leftarrow \mathrm{K̄}N}$ $\Sigma \pi$ invariant-mass spectrum in stopped-$K^{-}$ absorption in the deuteron, since the spectrum, reflecting the soft and hard deuteron momentum distribution, is expected to have a narrow quasifree component with an upper edge of $M=1430$ MeV/$c^2$, followed by a significant “high-momentum” tail toward the lower mass region, where a resonant formation of $\Lambda (1405)$ of any mass and width in a wide range will be clearly revealed. We introduce a “deviation” spectrum as defined by $\mathrm{DEV}$ $=$ $\mathrm{OBS}$ (observed or calculated) / $\mathrm{QF}$ (nonresonant quasifree), in which the resonant component can be seen as an isolated peak free from the QF shape.

The ${}^{18}\mathrm{F}(p,\alpha ){}^{15}\mathrm{O}$ reaction is the predominant destruction mechanism in novae of the radionuclide ${}^{18}\mathrm{F}$, a target of $\gamma$-ray observatories. Thus, its rate is important for understanding ${}^{18}\mathrm{F}$ production in novae. We have studied resonances in the ${}^{18}\mathrm{F}+p$ system by making a measurement of a proton-transfer reaction ${}^{18}\mathrm{F}(d,n)$. We have observed 15 ${}^{19}\mathrm{Ne}$ levels, 5 of which are below the proton threshold, including a subthreshold state, which has significant $l_p=0$ strength. Our data provide a direct determination of the spectroscopic strength of these states and new constraints on their spins and parities, thereby resolving a controversy, which involves the 8- and 38-keV resonances. The ${}^{18}\mathrm{F}(p,\alpha ){}^{15}\mathrm{O}$ reaction rate is reevaluated, which takes the subthreshold resonance and other new information determined in this experiment into account.

We have calculated the nuclear symmetry energy $E_{\mathrm{sym}}(\rho )$ up to densities of $4-5{\rho }_0$ with the effects from the Brown-Rho (BR) and Ericson scalings with the in-medium mesons included. Using the $V_{\mathrm{low}\hspace{0.5em}k}$ low-momentum interaction with and without such scalings, the equations of state (EOSs) of symmetric and asymmetric nuclear matter have been calculated using a ring-diagram formalism where the particle-particle-hole-hole ring diagrams are included to all orders. The EOSs for symmetric nuclear matter and neutron matter obtained with linear BR scaling are both overly stiff compared with the empirical constraints of Danielewicz et al. [Science 298, 1592 (2002)]. In contrast, satisfactory results are obtained by either using the nonlinear Ericson scaling or by adding a Skyrme-type three-nucleon force (TNF) to the unscaled $V_{\mathrm{low}\hspace{0.5em}k}$ interaction. Our results for $E_{\mathrm{sym}}(\rho )$ obtained with the nonlinear Ericson scaling are in good agreement with the empirical values of Tsang et al. [Phys. Rev. Lett. 102, 122701 (2009)] and Li et al. [Phys. Rev. C 72, 064611 (2005)], while those with the TNF are slightly below these values. For densities below the nuclear saturation density ${\rho }_0$, the results of the above calculations are nearly equivalent to each other and all are in satisfactory agreement with the empirical values.

We study cluster formation in strongly deformed states for ${}^{28}\mathrm{Si}$ and ${}^{32}\mathrm{S}$ using a macroscopic-microscopic model. The study is based on calculated total-energy surfaces, which are the sums of deformation-dependent macroscopic-microscopic potential-energy surfaces and rotational-energy contributions. We analyze the angular-momentum-dependent total-energy surfaces and identify the normal- and superdeformed states in ${}^{28}\mathrm{Si}$ and ${}^{32}\mathrm{S}$. We show that at sufficiently high angular momenta strongly deformed minima appear. The corresponding microscopic density distributions show cluster structures that closely resemble the ${}^{16}\mathrm{O}$ $+$ ${}^{12}\mathrm{C}$ and ${}^{16}\mathrm{O}$ $+$ ${}^{16}\mathrm{O}$ configurations. At still higher deformations, beyond the minima, valleys develop in the calculated surfaces. These valleys lead to mass divisions that correspond to the target-projectile configurations for which molecular resonance states have been observed. We discuss the relation between the one-body deformed minima and the two-body molecular-resonance states.

The resonant breakup of ${}^{19}\mathrm{C}$ on a proton target at 70 MeV/nucleon is analyzed using Faddeev–Alt, Grassberger, Sandhas (Faddeev-AGS) and continuum-discretized coupled-channels (CDCC) reaction frameworks, where in both cases a three-body model (${}^{18}$$\text{C}+n+p$) for the reaction is considered. Taking a ${}^{18}\mathrm{C}$ $+$ $p$ potential from a global nucleon-nucleus parametrization and a $L$-independent Gaussian proton-neutron potential, both methods provide very similar results for the calculated observables. However, when this simplified proton-neutron potential is replaced by the more realistic CD-Bonn potential, the breakup cross section, calculated with the Faddeev AGS formalism, decreases by almost one order of magnitude, largely underestimating the experimental data. From this calculation, we conclude that, within a core $+$ valence neutron model, the single-particle mechanism gives a negligible contribution to the calculated resonant breakup and therefore core-excitation mechanisms should be taken into account.

The proportionality between differential cross sections at vanishing linear momentum transfer and Gamow-Teller transition strength, expressed in terms of the unit cross section (${\mathrm{\sigma ̂}}_{\mathit{GT}}$), was studied as a function of target mass number for ($t$,${}^3\mathrm{He}$) and (${}^3\mathrm{He}$,$t$) reactions at $115A$ MeV and $140A$ MeV, respectively. Existing (${}^3\mathrm{He}$,$t$) and ($t$,${}^3\mathrm{He}$) data on targets with mass number $12⩽A⩽120$ were complemented with new and reevaluated ($t$,${}^3\mathrm{He}$) data on proton, deuteron, ${}^6\mathrm{Li}$, and ${}^{12}\mathrm{C}$ targets. It was found that in spite of the small difference in beam energies between the two probes, the unit cross sections have a nearly identical and simple dependence on target mass number $A$, for $A⩾12$: ${\mathrm{\sigma ̂}}_{\mathit{GT}}=109/A^{0.65}$. The factorization of the unit cross sections in terms of a kinematical factor, a distortion factor, and the strength of the effective spin-isospin transfer nucleus-nucleus interaction was investigated. Simple phenomenological functions depending on mass number $A$ were extracted for the latter two. By comparison with plane and distorted-wave Born approximation calculations, it was found that the use of a short-range approximation for knock-on exchange contributions to the transition amplitude results in overestimated cross sections for reactions involving the composite (${}^3\mathrm{He}$,$t$) and ($t$,${}^3\mathrm{He}$) probes.

Precise predictions of the antineutrino spectra emitted by nuclear reactors is a key ingredient in measurements of reactor neutrino oscillations as well as in recent applications to the surveillance of power plants in the context of nonproliferation of nuclear weapons. We report new calculations including the latest information from nuclear databases and a detailed error budget. The first part of this work is the so-called ab initio approach where the total antineutrino spectrum is built from the sum of all $\beta$ branches of all fission products predicted by an evolution code. Systematic effects and missing information in nuclear databases lead to final relative uncertainties in the $10–20\%$ range. A prediction of the antineutrino spectrum associated with the fission of ${}^{238}\mathrm{U}$ is given based on this ab initio method. For the dominant isotopes we developed a more accurate approach combining information from nuclear databases and reference electron spectra associated with the fission of ${}^{235}\mathrm{U}$, ${}^{239}\mathrm{Pu}$, and ${}^{241}\mathrm{Pu}$, measured at Institut Laue-Langevin (ILL) in the 1980s. We show how the anchor point of the measured total $\beta$ spectra can be used to suppress the uncertainty in nuclear databases while taking advantage of all the information they contain. We provide new reference antineutrino spectra for ${}^{235}\mathrm{U}$, ${}^{239}\mathrm{Pu}$, and ${}^{241}\mathrm{Pu}$ isotopes in the 2–8 MeV range. While the shapes of the spectra and their uncertainties are comparable to those of the previous analysis of the ILL data, the normalization is shifted by about $+3\%$ on average. In the perspective of the reanalysis of past experiments and direct use of these results by upcoming oscillation experiments, we discuss the various sources of errors and their correlations as well as the corrections induced by off-equilibrium effects.

Thermal photon emission is widely believed to reflect properties of the earliest, hottest evolution stage of the medium created in ultrarelativistic heavy-ion collisions. Previous computations of photon emission have been carried out using a hydrodynamical medium description with smooth, averaged initial conditions. Recently, more sophisticated hydrodynamical models that calculate observables by averaging over many evolutions with event-by-event fluctuating initial conditions (ICs) have been developed. Given their direct connection to the early time dynamics, thermal photon emission appears to be an ideal observable to probe fluctuations in the medium initial state. In this work, we demonstrate that including fluctuations in the ICs may lead to an enhancement of the thermal photon yield of about a factor of 2 in the region $2<p_T<4$ GeV$/c$ (where thermal photon production dominates the direct photon yield) compared to a scenario using smooth, averaged ICs. Consequently, a much better agreement with PHENIX data is found. This can be understood in terms of the strong temperature dependence of thermal photon production, translating into a sensitivity to the presence of hotspots in an event and thus establishing thermal photons as a suitable probe to characterize IC fluctuations.

We obtain within the statistical hadronization model (SHM) the hadron yields $\mathit{dh}/\mathit{dy}$ in heavy ion reactions at $\sqrt{s_{\mathit{NN}}}=2.76$ TeV. We discuss the dependence both on hadronization temperature $T$ and on critical hadronization pressure $P$. We consider observables distinguishing the hadronization models and conditions.

It is shown that the duality symmetry of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) equation can be interpreted as a symmetry under rotation of the BFKL kernel in the transverse space from $s$ channel (color-dipole model) to $t$ channel (Reggeized gluon formulation). It is argued that the duality symmetry also holds in the nonforward case due to a very special structure of the nonforward BFKL kernel, which can be written as a sum of three forward BFKL kernels. The duality symmetry is established by identifying the dual coordinates with the transverse coordinates of a nondiagonal dipole scattered off the target.

The $Q_{\mathrm{EC}}$ values of the superallowed ${\beta }^{+}$ emitters ${}^{10}\mathrm{C}$, ${}^{34}\mathrm{Ar}$, ${}^{38}\mathrm{Ca}$, and ${}^{46}\mathrm{V}$ have been measured with the JYFLTRAP Penning-trap mass spectrometer to be 3648.12(8), 6061.83(8), 6612.12(7), and 7052.44(10) keV, respectively. All four values are substantially improved in precision over previous results. Of the well-known superallowed emitters, only ${}^{14}\mathrm{O}$ has yet to have had its $Q_{\mathrm{EC}}$ value measured with a Penning trap.

High-spin levels of the neutron-rich ${}^{114}\mathrm{Ru}$ have been investigated by measuring the prompt $\gamma$ rays in the spontaneous fission of ${}^{252}\mathrm{Cf}$. The ground-state band and one-phonon $\gamma$-vibrational band have been extended up to 14${}^{+}$ and 9${}^{+}$, respectively. Two levels are proposed as the members of a two-phonon $\gamma$-vibrational band. A back bending (band crossing) has been observed in the ground-state band at $\hslash \omega \approx$ 0.40 MeV. Using the triaxial deformation parameters, the cranked shell model calculations indicate that this back bending in ${}^{114}\mathrm{Ru}$ should originate from the alignment of a pair of $h_{11/2}$ neutrons. Triaxial projected shell model calculations for the $\gamma$-vibrational band structures of ${}^{114}\mathrm{Ru}$ are in good agreement with the experimental data. However, when using the oblate deformation parameters, both of the above-calculated results are not in agreement with the experimental data.

The transient-field technique has been used in both conventional kinematics and inverse kinematics to measure the $g$ factors of the 2${}_1^{+}$ states in the stable even isotopes of Ru, Pd, and Cd. The statistical precision of the $g(2_1^{+})$ values has been significantly improved, allowing a critical comparison with the tidal-wave version of the cranking model recently proposed for transitional nuclei in this region.

Differential, total, and cumulative cross section calculations for neutral current neutrino scattering on ${}^{128,130}\mathrm{Te}$ isotopes are performed in the context of the quasiparticle random phase approximation by utilizing realistic two-nucleon forces. These isotopes are the main contents of detectors of ongoing experiments with multiple neutrino physics goals (COBRA and CUORE at Gran Sasso), including potential low-energy astrophysical neutrino (solar, supernova, geoneutrinos) detection. The incoming neutrino energy range adopted in our calculations (${\varepsilon }_{\nu }⩽100$ MeV) covers the low-energy $\beta$-beam neutrinos and the pion-muon stopped neutrino beams existing or planned to be conducted at future neutron spallation sources. The aim of these facilities is to measure neutrino-nucleus cross sections at low and intermediate neutrino energies with the hope of shedding light on open problems in neutrino-induced reactions on nuclei and neutrino astrophysics. Such probes motivate theoretical studies on weak responses of various nuclear systems; thus the evaluated cross sections may be useful in this direction.

Gamow-Teller (GT) and charge-exchange spin-dipole (SD) excitation energies in ${}^{90}\mathrm{Zr}$ and ${}^{208}\mathrm{Pb}$ are systematically studied to determine the appropriate magnitude of the tensor terms of the Skyrme interactions. We have found that the centroid energies of GT and SD excitations are sensitive to the adopted strengths of the triplet-even and triplet-odd tensor interactions. Especially, the $1^{-}$ SD state plays a crucial role in constraining the triplet-even part while the triplet-odd part is related rather to the GT peaks. Among the 36 $\mathrm{T}\mathit{IJ}$ parameter sets that include nonperturbatively the tensor terms, the four sets, T21, T32, T43, and T54, give reasonable results for the centroid energies in comparison with the experimental data. The sign and magnitude of the tensor terms are also discussed when these terms are added to the existing Skyrme interactions SGII and SLy5. The triplet-even strength can be constrained in a narrow range by using the available experimental data while further empirical data are needed to set a constraint on the triplet-odd term.

The neutron-induced fission cross section of ${}^{238}\mathrm{Pu}$ was determined using the surrogate ratio method. The $(n,f)$ cross section over an equivalent neutron energy range 5–20 MeV was deduced from inelastic $\alpha$-induced fission reactions on ${}^{239}\mathrm{Pu}$, with ${}^{235}\mathrm{U}$($\alpha ,{\alpha }^{\prime }f)$ and ${}^{236}\mathrm{U}$($\alpha ,{\alpha }^{\prime }f)$ used as references. These reference reactions reflect ${}^{234}\mathrm{U}$($n,f)$ and ${}^{235}\mathrm{U}$($n,f)$ yields, respectively. The deduced ${}^{238}\mathrm{Pu}$$(n,f$) cross section agrees well with standard data libraries up to $~$10 MeV, although larger values are seen at higher energies. The difference at higher energies is less than 20%.