The baryon self-energies are expressed in terms of the QCD condensates of the lowest dimension in symmetric and asymmetric nuclear matter within the QCD sum-rule approach. The self-energies are shown to satisfy the Gell-Mann–Okubo relations in the linear SU(3) breaking approximation. The results are in qualitative agreement with those obtained by the standard nuclear physics methods.

One possible scenario of chromofield decay in its initial stage of evolution is Schwinger's mechanism in restricted volume. It is assumed that initial chromofield energy can be represented as a collection of color flux tubes (CFT) stretched between receding nuclei. CFT expands up to some length until its breakup followed by the production of soft partons. A new formula for initial chromofield energy density is derived from the MacLerran-Venugopalan model to calculate CFT tension. It considers two possible ansatzes for saturation momentum. Color charge screening by produced partons is taken into account as well. A new formula for evolution of produced parton multiplicities based on the Wigner representation of the phase-space density of probability is also derived.

The momentum spectra of $K^{+}$ produced at small angles in proton-proton and proton-deuteron collisions have been measured at four beam energies, 1.826, 1.920, 2.020, and 2.650 GeV, using the ANKE spectrometer at COSY-Jülich. After making corrections for Fermi motion and shadowing, the data indicate that $K^{+}$ production near threshold is stronger in $pp$- than in $pn$-induced reactions. However, most of this difference could be made up by the unobserved $K^0$ production in the $pn$ case.

We derive a nonlocal Nambu-Jona-Lasinio model from QCD with a form factor exactly obtained in the infrared limit. Using this model, with all parameters properly fixed via QCD, we consider the case of finite temperature and compute the solution of the gap equation at low temperature, small momentum, and zero chemical potential. Taking the quark masses to be zero, we prove that the theory undergoes a phase transition with a critical temperature that is exactly determined. These results prove unequivocally that the picture of the vacuum of QCD as a liquid of instantons is a very good approximation.

We investigate the double differential neutrino-carbon quasielastic cross sections as measured by the MiniBooNE experiment. Our present treatment incorporates relativistic corrections in the nuclear response functions and includes the multinucleon component. We confirm our previous conclusion that it is possible to account for all the data without any modification of the axial mass. We also introduce the $Q^2$ distribution for charged and neutral current. The data point at a sizable multinucleon component beside the genuine quasielastic peak. They are also indicative of the collective character of the nuclear response, of interest for hadronic physics.

The ${}^{31}\mathrm{S}{(p,\gamma )}^{32}$Cl reaction is expected to provide the dominant break-out path from the SiP cycle in novae and is important for understanding enrichments of sulfur observed in some nova ejecta. We studied the ${}^{32}\mathrm{S}{{(}^3\mathrm{He},t)}^{32}$Cl charge-exchange reaction to determine properties of proton-unbound levels in ${}^{32}$Cl that have previously contributed significant uncertainties to the ${}^{31}\mathrm{S}{(p,\gamma )}^{32}$Cl reaction rate. Measured triton magnetic rigidities were used to determine excitation energies in ${}^{32}$Cl. Proton-branching ratios were obtained by detecting decay protons from unbound ${}^{32}$Cl states in coincidence with tritons. An improved ${}^{31}\mathrm{S}{(p,\gamma )}^{32}$Cl reaction rate was calculated including robust statistical and systematic uncertainties.

We discuss in this Brief Report the subleading contact interactions, or counterterms, in the ${}^3{P}_0$ channel of nucleon-nucleon scattering up to $O\left(Q^3\right)$, where, already at leading order, Weinberg's original power counting (WPC) scheme fails to fulfill renormalization group invariance due to the singular attraction of one-pion exchange. Treating the subleading interactions as perturbations and using renormalization group invariance as the criterion, we investigate whether WPC, although missing the leading order, could prescribe correct subleading counterterms. We find that the answer is negative and, instead, that the structure of counterterms agrees with a modified version of naive dimensional analysis. Using ${}^3{P}_0$ as an example, we also study the cutoffs where the subleading potential can be iterated together with the leading one.

We have examined the production of $J/\psi$ mesons in high-energy proton-proton and proton-nucleus collisions at beam energies in the range from 158 to 920 GeV, available from different fixed-target experiments. In the employed model $J/\psi$ production in hadronic collisions is assumed to be a factorizable two-step process: (i) production of a $c\overline{c}$ pair, which can be reliably described by perturbative QCD, and (ii) formation of a $J/\psi$ resonance from the $c\overline{c}$ pair, which can be conveniently parametrized by incorporating different existing physical mechanisms of color neutralization. We show that, for lower collision energies, $J/\psi$ production through quark-antiquark annihilation gives a larger contribution at higher $x_F$, while gluon-gluon fusion dominates the production at smaller $x_F$. For proton-nucleus collisions the model takes into account both the initial-state modification of parton distributions in nuclei and the final-state interaction of the produced $c\overline{c}$ pairs with the target nucleons. The model is found to give a reasonable description of data on $J/\psi$ production in protonic and proton-nucleus collisions for different existing fixed-target experiments. For proton-nucleus collisions, our calculations show a non-negligible dependence of the final state nuclear dissociation of $J/\psi$ mesons on the energy of the incident proton beam. The model has been applied to predict the $J/\psi$ production and suppression expected in proton-nucleus collisions at energies relevant to GSI Facility for Antiproton and Ion Research, the upcoming accelerator facility at Darmstadt, Germany. The amount of suppressions, for different mechanisms of $J/\psi$ hadronization, has been found to be distinguishably different, which might help an experimental settlement of the much controversial issue of color neutralization.

The rapidity dependence of two-particle momentum correlations can be used to probe the viscosity of the liquid produced in heavy nuclei collisions at the Relativistic Heavy Ion Collider (RHIC). We reexamine this probe in light of the recent experimental analyses of the azimuthal-angle dependence of number correlations, which demonstrate the importance of initial state fluctuations propagated by hydrodynamic flow in these correlations. The NEXSPHERIO model combines fluctuating initial conditions with viscosity-free hydrodynamic evolution and, indeed, has been shown to describe azimuthal correlations. We use this model to compute the number density correlation $R_2$ and the momentum current correlation function C, at low transverse momentum in Au + Au collisions at $\sqrt{s_{NN}}=200$ GeV. The correlation function C is sensitive to details of the collision dynamics. Its longitudinal width is expected to broaden under the influence of viscous effects and narrow in the presence of sizable radial flow. While the NEXSPHERIO model qualitatively describes the emergence of a near-side ridge-like structure for both the $R_2$ and C observables, we find that it predicts a longitudinal narrowing of the near-side peak of these correlation functions for increasing number of participants in contrast with recent observations by the STAR Collaboration of a significant broadening in most central collisions relative to peripheral collisions.

A scheme that elucidates the nature of critical point symmetries in deformed odd-A nuclei by linking them to critical point symmetries of neighboring even-even nuclei is introduced. Specifically, a new symmetry, called SX(3), is advanced that shows primary characteristics of an assumed strong-coupling limit for odd-A systems. It is found that the SX(3) symmetry can be used to identify the soft collective structures in odd-A system. A preliminary application of the new scheme to describe the lowest positive parity bands of ${}^{193}$Ir is also shown.

A spectroscopic investigation of the $\gamma$ decays from excited states in ${}^{159}\mathrm{Er}$ has been performed to study the changing structural properties exhibited as ultrahigh spins ($I>60\hslash$) are approached. The nucleus of ${}^{159}\mathrm{Er}$ was populated by the reaction ${}^{116}\mathrm{Cd}{(}^{48}\mathrm{Ca},5n\gamma )$ at a beam energy of 215 MeV, and the resulting $\gamma$ decays were studied using the Gammasphere spectrometer. New rotational bands and extensions to existing sequences were observed, which are discussed in terms of the cranked shell model, revealing a diverse range of quasiparticle configurations. At spins around $50\hslash$, there is evidence for a change from dominant prolate collective motion at the yrast line to oblate non-collective structures via the mechanism of band termination. A possible strongly deformed triaxial band occurs at these high spins, which indicates collectivity beyond $50\hslash$. The high-spin data are interpreted within the framework of cranked Nilsson-Strutinsky calculations.

The reaction ${}^{16}$O $+$ ${}^{208}$Pb is a benchmark in nuclear reaction studies as it involves two doubly magic nuclei. New measurements of back-scattered projectile-like fragments at sub-barrier energies show that the probability of two-proton ($2p$) transfer is much larger than that of $\alpha$-particle transfer. At energies around the fusion barrier the probability for $2p$ transfer is $\sim 10\%$, similar to that for one-proton transfer. The $2p$ transfer probabilities are enhanced by up to an order of magnitude compared to calculations based on an independent particle picture as simulated by the fully microscopic time-dependent Hartree-Fock model (TDHF). Since beyond mean-field correlations like nucleon pairing are not included in the TDHF model, the enhancement indicates strong pairing correlations between the transferred protons. $2p$ transfer leads to excitation energies (most likely in the target-like nucleus) up to $\sim 13$ MeV, indicating that it may represent an effective doorway for the dissipation of energy and thus provide a microscopic mechanism toward understanding the inhibition of fusion and energies both above and below the barrier.

Background: Multicenter (molecular) structures can play an important role in light nuclei. The highly deformed rotational band in ${}^{10}$Be with a bandhead at 6.179 MeV has been observed recently and suggested to have an exotic $\alpha$:$2n$:$\alpha$ configuration.

Purpose: Search for states with $\alpha$:$pn$:$\alpha$ two-center molecular configurations in ${}^{10}$B that are analogous to the states with $\alpha$:$2n$:$\alpha$ structure in ${}^{10}$Be.

Methods: The $T=1$ isobaric analog states in ${}^{10}$B were studied in the energy range of $E_x=8.7\text{--}12.1$ MeV using the reaction ${}^1$H(${}^9$Be,$\alpha$)${}^6$Li*($T=1$, 0${}^{+}$, 3.56 MeV). An $R$-matrix analysis was used to extract parameters for the states observed in the ($p$,$\alpha$) excitation function.

Results: Five $T=1$ states in ${}^{10}$B have been identified. The known 2${}^{+}$ and 3${}^{-}$ states at 8.9 MeV have been observed and their partial widths have been measured. The spin parities and partial widths for three higher-lying states were determined.

Conclusions: Our data support theoretical predictions that the 2${}^{+}$ state at 8.9 MeV (isobaric analog of the 7.54-MeV state in ${}^{10}$Be) is a highly clustered state and can be identified as a member of the $\alpha$:$np$:$\alpha$ rotational band. The next member of this band, the 4${}^{+}$ state, has not been found. A very broad 0${}^{+}$ state at 11 MeV that corresponds to pure $\alpha +{}^6\mathrm{Li}$(0${}^{+}$, $T=1$) configuration is suggested and it might be related to similar structures found in ${}^{12}$C, ${}^{18}$O, and ${}^{20}$Ne.

High transverse momentum ($P_T$) processes are considered to be an important tool to probe and understand the medium produced in ultrarelativistic heavy-ion collisions via the interaction of hard, perturbatively produced partons with the medium. In this context, triggered hard dihadron correlations constitute a class of observables set between hard single inclusive hadrons (dominated by the leading jet fragments) and fully reconstructed jets; while they probe some features of the perturbative QCD evolution of a parton shower in the medium, they do not suffer from the problem of finding a suitable separation between soft hadrons coming from perturbative jets and soft hadrons coming from the nonperturbative medium as the identification of full jets does. On the other hand, the trigger requirement introduces nontrivial complications to the process, which makes the medium modification of the correlation pattern difficult and nonintuitive to understand. In this work, we review the basic physics underlying triggered dihadron correlations and make a systematic comparison of several combinations of medium evolution and parton-medium interaction models with the available data from 200-AGeV Au-Au collisions at the BNL Relativistic Heavy Ion Collider (RHIC). We also discuss the expected results for 2.76-ATeV Pb-Pb collisions at the CERN Large Hadron Collider (LHC).

The formation of clusters in nuclear matter is investigated, which occurs, e.g., in low-energy heavy-ion collisions or core-collapse supernovae. In astrophysical applications, the excluded volume concept is commonly used for the description of light clusters. Here we compare a phenomenological excluded volume approach to two quantum many-body models, the quantum statistical model and the generalized relativistic mean-field model. All three models contain bound states of nuclei with mass number $A\le 4$. It is explored to which extent the complex medium effects can be mimicked by the simpler excluded volume model, regarding the chemical composition and thermodynamic variables. Furthermore, the role of heavy nuclei and excited states is investigated by use of the excluded volume model. At temperatures of a few MeV the excluded volume model gives a poor description of the medium effects on the light clusters, but there the composition is actually dominated by heavy nuclei. At larger temperatures there is a rather good agreement, whereas some smaller differences and model dependencies remain.

Photoneutron cross sections were measured for ${}^{118}$Sn, ${}^{119}$Sn, ${}^{120}$Sn, ${}^{122}$Sn, and ${}^{124}$Sn near neutron threshold with quasi-monochromatic laser-Compton scattering $\gamma$ rays. A systematic analysis of the present photoneutron data and existing neutron-capture data is made using the $\gamma$-ray strength function on the basis of the HFB + QRPA model of $E1$ strength supplemented with a pygmy dipole resonance, which was deduced from a previous study on ${}^{116}$Sn and ${}^{117}$Sn. Radiative neutron capture cross sections for two radioactive nuclei, ${}^{121}$Sn and ${}^{123}$Sn, are deduced through the $\gamma$-ray strength function method.

A fully symmetry unrestricted time-dependent density functional theory extended to include pairing correlations is used to calculate properties of the isovector giant dipole resonances of the deformed open-shell nuclei ${}^{172}$Yb (axially deformed), ${}^{188}$Os (triaxially deformed), and ${}^{238}$U (axially deformed) and to demonstrate good agreement with experimental data on nuclear photo-absorption cross sections for two different Skyrme force parametrizations of the energy density functionals SkP and SLy4.

A dynamical coupled-channels study of a $K^{*}{\overline{K}}^{*}$ state with isospin 0 and $\omega \phi$ state is performed within both the chiral SU(3) quark model and the extended chiral SU(3) quark model by solving a resonating group method (RGM) equation. The model parameters are taken from our previous work, which gave a satisfactory description of the energies of the octet and decuplet baryon ground states, the binding energy of the deuteron, the nucleon-nucleon ($NN$) scattering phase shifts, and the hyperon-nucleon ($YN$) cross sections. The results show that the interactions of $K^{*}{\overline{K}}^{*}$ states are attractive, which consequently result in $K^{*}{\overline{K}}^{*}$ bound states with the binding energies of about 10–70 MeV, and contrarily, no $\omega \phi$ bound state is obtained. The channel coupling effect of $K^{*}{\overline{K}}^{*}$ and $\omega \phi$ is found to be considerably large, which makes the binding of $K^{*}{\overline{K}}^{*}$ 5–45 MeV deeper. The plausible interpretation of $f_0\left(1710\right)$ and $X\left(1812\right)$ being $K^{*}{\overline{K}}^{*}$ dominated states is briefly discussed.