We report on results obtained with the event-shape engineering technique applied to Pb-Pb collisions at $\sqrt{s_{\mathit{NN}}}=2.76$ TeV. By selecting events in the same centrality interval, but with very different average flow, different initial-state conditions can be studied. We find the effect of the event-shape selection on the elliptic flow coefficient $v_2$ to be almost independent of transverse momentum $p_{\mathrm{T}}$, which is as expected if this effect is attributable to fluctuations in the initial geometry of the system. Charged-hadron, -pion, -kaon, and -proton transverse momentum distributions are found to be harder in events with higher-than-average elliptic flow, indicating an interplay between radial and elliptic flow.

In this article, we study the coherent pion production in the neutrino-nucleus interaction in the resonance region using the formalism based on the partially conserved axial current (PCAC) theorem which relates the neutrino-nucleus cross section to the pion-nucleus elastic cross section. The pion-nucleus elastic cross section is calculated using the Glauber model in terms of pion-nucleon cross sections obtained by parametrizing the experimental data. We calculate the differential and integrated cross sections for charged current coherent pion production in neutrino-carbon scattering. The results of integrated cross-section calculations are compared with the measured data. Predictions for the differential and integrated cross sections for coherent pion productions in neutrino-iron scattering using the above formalism are also made.

We investigate the effects of the odd-state part of bare $\mathrm{\Lambda }\mathrm{\Lambda }$ interactions on the structure of neutron stars (NSs) by constructing equations of state (EOSs) for uniform nuclear matter containing $\mathrm{\Lambda }$ and ${\mathrm{\Sigma }}^{-}$ hyperons with use of the cluster variational method. The isoscalar part of the Argonne v18 two-nucleon potential and the Urbana IX three-nucleon potential are employed as the interactions between nucleons, whereas, as the bare $\mathrm{\Lambda }N$ and even-state $\mathrm{\Lambda }\mathrm{\Lambda }$ interactions, two-body central potentials that are determined so as to reproduce the experimental data on single- and double-$\mathrm{\Lambda }$ hypernuclei are adopted. In addition, the ${\mathrm{\Sigma }}^{-}N$ interaction is constructed so as to reproduce the empirical single-particle potential of ${\mathrm{\Sigma }}^{-}$ in symmetric nuclear matter. Since the odd-state part of the $\mathrm{\Lambda }\mathrm{\Lambda }$ interaction is not known owing to lack of experimental data, we construct four EOSs of hyperonic nuclear matter, each with a different odd-state part of the $\mathrm{\Lambda }\mathrm{\Lambda }$ interaction. The EOS obtained for NS matter becomes stiffer as the odd-state $\mathrm{\Lambda }\mathrm{\Lambda }$ interaction becomes more repulsive, and correspondingly the maximum mass of NSs increases. It is interesting that the onset density of ${\mathrm{\Sigma }}^{-}$ depends strongly on the repulsion of the odd-state $\mathrm{\Lambda }\mathrm{\Lambda }$ interaction. Furthermore, we take into account the three-baryon repulsive force to obtain results that are consistent with observational data on heavy NSs.

The elastic scattering and breakup of the halo nucleus ${}^{11}\mathrm{Be}$ on protons at an incident energy of $26.9A$ MeV have been measured. The ${}^{11}\mathrm{Be}+p$ elastic scattering cross sections at various energies, including the present one, are systematically analyzed with the Chapel Hill 89 (CH89) and Koning-Delaroche (KD) global optical model potentials (OMPs), and the corresponding normalization factors are obtained. An extended version of the continuum-discretized coupled-channels (XCDCC) formalism, including dynamic core excitation effects, is applied to analyze the elastic scattering and breakup data. It is found that the core excitation plays a moderate role in the elastic scattering and breakup reaction of the halo nucleus ${}^{11}\mathrm{Be}$, being consistent with previous results at higher energies.

Two types of average neutron-proton interaction formulas are compared: In the first type, neutron-proton interactions for even-even and odd-$A$ nuclei extracted from experimental binding energies show a smooth behavior as a function of mass number $A$ and are dominated by the contribution from the symmetry energy. Whereas in the second type large systematic staggering is seen between even-$A$ and odd-$A$ nuclei. This deviation is understood in terms of the additional neutron-proton interaction in odd-odd nuclei relative to the neighboring even-even and odd-$A$ systems. We explore three possible ways to extract this additional interaction from the binding energy difference of neighboring nuclei. The extracted interactions are positive in nearly all cases and show weak dependence on the mass number. The empirical interactions are also compared with theoretical values extracted from recent nuclear mass models where large unexpected fluctuations are seen in certain nuclei. The reproduction of the residual neutron-proton interaction and the correction of those irregular fluctuations can be a good criterion for the refinement of those mass models.

Based on mean field calculations with Skyrme interactions, we extract a constraint on the isovector effective mass in nuclear matter at saturation density ${\rho }_0$, i.e., $m_v^{*}\left({\rho }_0\right)=(0.77\pm 0.03)m$ by combining the experimental data of the centroid energy of the isovector giant dipole resonance (IVGDR) and the electric dipole polarizability ${\alpha }_{\mathrm{D}}$ in ${}^{208}\mathrm{Pb}$. Meanwhile, the isoscalar effective mass at ${\rho }_0$ is determined to be $m_s^{*}\left({\rho }_0\right)=(0.91\pm 0.05)m$ by analyzing the measured excitation energy of the isoscalar giant quadrupole resonance (ISGQR) in ${}^{208}\mathrm{Pb}$. From the constrained $m_s^{*}\left({\rho }_0\right)$ and $m_v^{*}\left({\rho }_0\right)$, we obtain the isospin splitting of nucleon effective mass in asymmetric nuclear matter of isospin asymmetry $\delta$ at ${\rho }_0$ as $[m_n^{*}({\rho }_0,\delta )-m_p^{*}({\rho }_0,\delta )]/m=\mathrm{\Delta }{m}_1^{*}\left({\rho }_0\right)\delta +O\left({\delta }^3\right)$ with the linear isospin splitting coefficient $\mathrm{\Delta }{m}_1^{*}\left({\rho }_0\right)=0.33\pm 0.16$. We notice that using the recently corrected data on the ${\alpha }_{\mathrm{D}}$ in ${}^{208}\mathrm{Pb}$ with the contribution of the quasideuteron effect subtracted slightly enhances the isovector effective mass to $m_v^{*}\left({\rho }_0\right)=(0.80\pm 0.03)m$ and reduces the linear isospin splitting coefficient to $\mathrm{\Delta }{m}_1^{*}\left({\rho }_0\right)=0.27\pm 0.15$. Furthermore, the constraints on $m_v^{*}\left(\rho \right),m_s^{*}\left(\rho \right)$, and $\mathrm{\Delta }{m}_1^{*}\left(\rho \right)$ at other densities are obtained from the similar analyses and we find that the $\mathrm{\Delta }{m}_1^{*}\left(\rho \right)$ increases with the density.

We reply to the Comment by Arrington, which concerns the proton radius extracted from the elastic electron-proton scattering data by using the assumption of nonidentical protons. We agree that the extracted radius should be 0.853 fm. We briefly point out the corresponding consequence in the result of our original paper.

The structure of ${}^{35}\mathrm{P}$ was studied with a one-proton knockout reaction at 88 MeV/u from a ${}^{36}\mathrm{S}$ projectile beam at NSCL. The $\gamma$ rays from the depopulation of excited states in ${}^{35}\mathrm{P}$ were detected with GRETINA, while the ${}^{35}\mathrm{P}$ nuclei were identified event-by-event in the focal plane of the S800 spectrograph. The level scheme of ${}^{35}\mathrm{P}$ was deduced up to 7.5 MeV using $\gamma \text{−}\gamma$ coincidences. The observed levels were attributed to proton removals from the $sd$ shell and also from the deeply bound $p_{1/2}$ orbital. The orbital angular momentum of each state was derived from the comparison between experimental and calculated shapes of individual $(\gamma$-gated) parallel momentum distributions. Despite the use of different reactions and their associate models, spectroscopic factors, $C^{2}S$, derived from the ${}^{36}\mathrm{S}(-1p)$ knockout reaction agree with those obtained earlier from ${}^{36}\mathrm{S}\left(d,{}^3\mathrm{He}\right)$ transfer, if a reduction factor $R_s$, as deduced from inclusive one-nucleon removal cross sections, is applied to the knockout transitions. In addition to the expected proton-hole configurations, other states were observed with individual cross sections of the order of 0.5 mb. Based on their shifted parallel momentum distributions, their decay modes to negative parity states, their high excitation energy (around 4.7 MeV), and the fact that they were not observed in the $\left(d,{}^3\mathrm{He}\right)$ reaction, we propose that they may result from a two-step mechanism or a nucleon-exchange reaction with subsequent neutron evaporation. Regardless of the mechanism, that could not yet be clarified, these states likely correspond to neutron core excitations in ${}^{35}\mathrm{P}$. This newly identified pathway, although weak, offers the possibility to selectively populate certain intruder configurations that are otherwise hard to produce and identify.

The nuclei that constitute a crystalline lattice oscillate relative to each other with a very low energy that is not sufficient to penetrate through the Coulomb barriers separating them. An additional energy, which is needed to tunnel through the barrier and fuse, can be supplied by external electromagnetic waves (x rays or synchrotron radiation). Exposing the solid compound LiD (lithium deuteride) to x rays for the duration of 111 h, we detect 88 events of nuclear fusion $d+{}^6\mathrm{Li}\to {}^8{\mathrm{Be}}^{*}$. Our theoretical estimate agrees with what we observed. One possible application of the phenomenon we found is in measurements of the rates of various nuclear reactions (not necessarily fusion) at extremely low energies inaccessible in accelerator experiments.

Prompt photon production in $\sqrt{s_{NN}}=2.76$-TeV $\mathrm{Pb}+\mathrm{Pb}$ collisions has been measured by the ATLAS experiment at the Large Hadron Collider using data collected in 2011 with an integrated luminosity of $0.14 {\mathrm{nb}}^{-1}$. Inclusive photon yields, scaled by the mean nuclear thickness function, are presented as a function of collision centrality and transverse momentum in two pseudorapidity intervals, $\left|\eta \right|<1.37$ and $1.52\le \left|\eta \right|<2.37$. The scaled yields in the two pseudorapidity intervals, as well as the ratios of the forward yields to those at midrapidity, are compared to the expectations from next-to-leading-order perturbative QCD (pQCD) calculations. The measured cross sections agree well with the predictions for proton-proton collisions within statistical and systematic uncertainties. Both the yields and the ratios are also compared to two other pQCD calculations, one which uses the isospin content appropriate to colliding lead nuclei and another which includes nuclear modifications to the nucleon parton distribution functions.

We argue that a crucial determinant of the acceptance dependence of fluctuation measures in heavy-ion collisions is the range of correlations in the momentum space, e.g., in rapidity, $\mathrm{\Delta }{y}_{\mathrm{corr}}$. The value of $\mathrm{\Delta }{y}_{\mathrm{corr}}\sim 1$ for critical thermal fluctuations is determined by the thermal rapidity spread of the particles at freeze-out, and has little to do with position space correlations, even near the critical point where the spatial correlation length $\xi$ becomes as large as 2–3 fm (this is in contrast to the magnitudes of the cumulants, which are sensitive to $\xi$). When the acceptance window is large, $\mathrm{\Delta }y\gg \mathrm{\Delta }{y}_{\mathrm{corr}}$, the cumulants of a given particle multiplicity, ${\kappa }_k$, scale linearly with $\mathrm{\Delta }y$, or mean multiplicity in acceptance, $\langle N\rangle$, and cumulant ratios are acceptance independent. In the opposite regime, $\mathrm{\Delta }y\ll \mathrm{\Delta }{y}_{\mathrm{corr}}$, the factorial cumulants, ${\widehat{\kappa }}_k$, scale as ${\left(\mathrm{\Delta }y\right)}^k$, or ${\langle N\rangle }^k$. We demonstrate this general behavior quantitatively in a model for critical point fluctuations, which also shows that the dependence on transverse momentum acceptance is very significant. We conclude that the extension of rapidity coverage as proposed by the STAR Collaboration should significantly increase the magnitude of the critical point fluctuation signatures.

Background: At high density deconfinement of hadronic matter may occur leading to quark matter. The immense densities reached in the inner core of massive neutron stars may be sufficient to facilitate the transition.

Purpose: To investigate a crossover transition between two phenomenological models which epitomize quantum chromodynamics in two different regimes, while incorporating the influence of quark degrees of freedom in both.

Method: We use the Hartree-Fock quark-meson coupling model and the proper-time regularized three-flavor Nambu–Jona-Lasinio model to describe hadronic and quark matter, respectively. Hybrid equations of state are obtained by interpolating the energy density as a function of total baryonic density and calculating the pressure.

Results: Equations of state for hadronic, quark, and hybrid matter and the resulting mass versus radius curves for hybrid stars are shown, as well as other relevant physical quantities such as species fractions and the speed of sound in matter.

Conclusions: The observations of massive neutron stars can certainly be explained within such a construction. However, the so-called thermodynamic correction arising from an interpolation method can have a considerable impact on the equation of state. The interpolation dependency of and physical meaning behind such corrections require further study.

$\beta$-decay rates of ${}^{121–131}\mathrm{Cs}$ have been calculated in the framework of the neutron-proton interacting boson-fermion model (IBFM-2). For odd-$A$ nuclei, the decay operator can be written in a relatively simple form in terms of the one-nucleon transfer operator. Previous studies of $\beta$ decay in IBFM-2 were based on a transfer operator obtained by using the number operator approximation (NOA). In this work a new form of the one-nucleon transfer operator, derived microscopically without the NOA approximation, is used. The results from both approaches are compared and show that the deviation from experimental data is reduced without using the NOA approximation. Indications about the renormalization of the Fermi and Gamow-Teller matrix elements are discussed. This is a further step toward a more complete description of low-lying states in medium and heavy nuclei which is necessary to compute reliable matrix elements in studies of current active interest such as double-$\beta$ decay or neutrino absorption experiments.

Using the improved scission-point model, the mass distributions are calculated for induced fission of several Po and Ir isotopes. The calculated mass distributions and mean total kinetic energies of fission fragments are compared with the existing experimental data. The revealed coexistence of both symmetric and asymmetric modes in the $\beta$-delayed fission of ${}^{194,196}\mathrm{At}$ is in agreement with the experimental observations. The change of the shape of mass distribution with increasing $A$ of fissioning ${}^A\mathrm{Ir}$ nucleus from asymmetric for ${}^{185}\mathrm{Ir}$ to symmetric for ${}^{193}\mathrm{Ir}$ is found.

A systematic analysis of hot fusion reactions with a comparison to experimental cross sections related to the synthesis of superheavy elements is carried out using the hivap code. A single parameter set is found which when implemented in the hivap computer code, describes experimental production cross sections for reactions using a ${}^{48}\mathrm{Ca}$ beam on actinide targets reasonably well. A simple scaling based on the mass asymmetry of the projectile-target system is introduced for projectiles lighter than ${}^{48}\mathrm{Ca}$. It is seen that only three parameters scaled by a constant factor are required to describe cross-section data obtained using lighter projectiles. The projectile dependence on the production cross section is also studied. From these investigations, new reactions with ${}^{48}\mathrm{Ca}$ incident on various actinide targets are proposed for the production of unknown heavier isotopes of $Z=116$ and 118 and for the synthesis of new superheavy elements with $Z=119$ and 120.

Transverse momentum $\left(p_{\mathrm{T}}\right)$ spectra of pions, kaons, and protons up to $p_{\mathrm{T}}=20\text{GeV}/c$ have been measured in Pb-Pb collisions at $\sqrt{s_{\mathit{NN}}}=2.76\text{TeV}$ using the ALICE detector for six different centrality classes covering 0%–80%. The proton-to-pion and the kaon-to-pion ratios both show a distinct peak at $p_{\mathrm{T}}\approx 3\text{GeV}/c$ in central Pb-Pb collisions that decreases for more peripheral collisions. For $p_{\mathrm{T}}>10\text{GeV}/c$, the nuclear modification factor is found to be the same for all three particle species in each centrality interval within systematic uncertainties of 10%–20%. This suggests there is no direct interplay between the energy loss in the medium and the particle species composition in the hard core of the quenched jet. For $p_{\mathrm{T}}<10\text{GeV}/c$, the data provide important constraints for models aimed at describing the transition from soft to hard physics.

Classic calculations of the magnetic moments ${\mu }_p$ and ${\mu }_n$ of the nucleons using the traditional exponential kernel show instability with respect to variations of the Borel mass as well as arbitrariness with respect to the choice of the onset of perturbative QCD. The use of a polynomial kernel, the coefficients of which are determined by the masses of the nucleon resonances stabilizes the calculation and provides much better damping of the unknown contribution of the nucleon continuum. The method is also applied to the evaluation of the coupling $g_A$ of proton to the axial current and to the strong part of the neutron-proton mass difference $\delta M_{np}$. All these quantities depend sensitively on the value of the 4-quark condensate $\langle 0\mid \overline{q}q\overline{q}q\mid 0\rangle$, and the value $\langle 0\mid \overline{q}q\overline{q}q\mid 0\rangle \simeq 1.6{\langle 0\mid \overline{q}q\mid 0\rangle }^2$ reproduces the experimental results.