In this work we present the results of a theoretical analysis of the data on photoproduction of the $f_0\left(980\right)$ meson in the laboratory photon energy between 3.0 and 3.8 GeV. A comparison is done to the measurements performed by the CLAS Collaboration at the JLab accelerator for the exclusive reaction $\gamma p\to p{f}_0\left(980\right)$. In the analysis the partial $S$-wave differential cross section is described by a model based on the Regge approach with reggeized exchanges and distinct scenarios for the $f_0\left(980\right)\to V\gamma$ coupling considered. It is shown that such a process can provide information on the resonance structure and production mechanism.

A noncritical holographic QCD model constructed in the six dimensional anti–de Sitter (AdS${}_6$) supergravity background is employed to study a baryon. It is shown that the size of the baryon is of order one with respect to the $\lambda$, however, it is smaller than the scale of the dual QCD. An effective four-dimensional action for the nucleon is obtained in terms of the meson exchange potentials. All meson-nucleon couplings in the noncritical AdS${}_6$ background are calculated. Results obtained using our model are compared with predictions of four modern phenomenological interaction models. Also, our numerical results are compared with the results of the Sakai-Sugimoto (SS) model which indicate that the noncritical holographic QCD model can be a good toy to calculate the meson-nucleon couplings.

Pre- and post-scission neutron multiplicities are measured for the three isotopes of Fr (${}^{217}$Fr, ${}^{215}$Fr, and ${}^{213}$Fr) in the excitation energy range of 48–91.8 MeV. Out of these three isotopes, ${}^{213}$Fr has shell closure ($N_C=126$) while the other two are non-closed-shell nuclei. Statistical model calculations using Kramers’ fission width are performed to investigate shell effects on the dissipation strength which fit the experimental data. It is observed that shell correction to the binding energies of the evaporated particles strongly affects the fitted values of the dissipation strength. However, the best-fit dissipation strength is only weakly influenced by the inclusion of shell correction in fission barrier.

${}^{230}$U and its daughter nuclide ${}^{226}$Th are promising therapeutic nuclides for application in targeted α therapy of cancer. We investigated the feasibility of producing ${}^{230}$U/${}^{226}$Th via irradiation of ${}^{230}$Th with ${}^3$He particles according to the reaction ${}^{230}$Th(${}^3$He,3$n$)${}^{230}$U. The experimental excitation function for this reaction is reported here. Cross sections were measured by using thin targets of ${}^{230}$Th prepared by electrodeposition, and ${}^{230}$U yields were analyzed by using α spectrometry. Beam intensities were obtained via monitor reactions on aluminum foils by using high-resolution γ spectrometry and International Atomic Energy Agency recommended cross sections. Incident particle energies were calculated by using the srim-2003 code. The experimental cross sections for the reaction ${}^{230}$Th(${}^3$He,3$n$)${}^{230}$U are in good agreement with model calculations by the empire-3 code once breakup and transfer reactions are properly considered in the incident channel. The obtained cross sections are too low to allow for the production of ${}^{230}$U/${}^{226}$Th in clinically relevant levels.

Within a multiphase transport (AMPT) model, dijet asymmetry is studied in $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{s_{{}_{NN}}}=2.76$ TeV. It is found that a large dijet asymmetry ($A_J$) is produced by strong interactions between jets and partonic matter. It is demonstrated that hadronization and final-state hadronic rescatterings have little effect on $A_J$. The final $A_J$ is found to be driven by both initial $A_J$ and partonic jet energy loss, which is consistent with an increasing jet energy loss in a hot and strongly interacting partonic medium in more central $\mathrm{Pb}+\mathrm{Pb}$ collisions.

Within the framework of a thermal model with its parameters fitted to the results from an isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model, we have studied the pion in-medium effect on the charged-pion ratio in heavy-ion collisions at various energies. We find that due to the cancellation between the effects from pion-nucleon $s$-wave and $p$-wave interactions in nuclear medium, the ${\pi }^{-}/{\pi }^{+}$ ratio generally decreases after including the pion in-medium effect. The effect is larger at lower collision energies as a result of narrower pion spectral functions at lower temperatures.

We propose an improved version of the antisymmetrized quasicluster model (AQCM) to describe a smooth transition from the $\alpha$-cluster wave function to the $jj$-coupling shell model wave function and apply it to the ground state of ${}^{12}$C. The cluster-shell transition in ${}^{12}$C is characterized in AQCM by only two parameters: $R$ representing the distance between $\alpha$ clusters and the center of mass and $\Lambda$ describing the break of $\alpha$ clusters. The optimal AQCM wave function for the ground state of ${}^{12}$C is an intermediate state between the three-$\alpha$ cluster state and the shell model state with the $p_{3/2}$ subshell closure configuration. The result is consistent with that of the antisymmetrized molecular dynamics (AMD), and the optimal AQCM wave function quantitatively agrees with the AMD one, although the number of degrees of freedom in AQCM is significantly fewer.

Predictions of cross sections and analyzing powers using $g$-folding optical potentials for the scattering of $71A$ MeV ${}^{6,8}$He ions from (polarized) hydrogen are compared with data. A $g$-folding model in which exchange amplitudes are evaluated explicitly was used with wave functions of ${}^{6,8}$He specified from a no-core shell model that used a complete $(0+2+4)\hslash \omega$ basis. The analyzing powers reveal some sensitivities to the details of the wave functions, especially in the case of halo nuclei.

Background: The search for violations of Lorentz invariance is nowadays motivated by attempts to unify the standard model of particle physics with general relativity. Such theories of “quantum gravity” predict Lorentz-violating signals that could be detected in low-energy precision experiments. In this context, Lorentz invariance has been tested poorly in the weak interaction.

Purpose: We explore the possibility that the weak interaction violates Lorentz, and in particular rotational, invariance in neutron and allowed nuclear $\beta$ decay.

Method: A broad class of Lorentz-violating effects is considered in an effective field theory approach, wherein the standard propagator of the $W$ boson acquires an additional Lorentz-violating tensor.

Results: The general decay rate for allowed $\beta$ decay that incorporates the modified $W$-boson propagator is derived. The resulting Lorentz-violating signals are discussed for the different types of $\beta$-decay transitions: Fermi, Gamow-Teller, and mixed. We study the implications of our formalism for dedicated $\beta$-decay experiments. We give a short overview of the few relevant experiments that have been performed in the past or are ongoing.

Conclusions: Our work provides a general theoretical framework that should be used for designing and interpreting $\beta$-decay experiments that search for Lorentz violation. In particular, it determines the kind of experiments that are necessary to probe different parameters that quantify Lorentz violation, and it establishes their sensitivity.

The potential barriers governing the reactions ${}^{58}$Fe+${}^{244}$Pu, ${}^{238}$U+${}^{64}$Ni, and ${}^{238}$U+${}^{72}$Ge have been determined from a liquid-drop model taking into account the proximity energy, shell energies, rotational energy, and deformation of the incoming nuclei in the quasimolecular shape valley. Double-humped potential barriers appear in these entrance channels. The external saddle-point corresponds to two touching ellipsoidal nuclei when the shell and pairing effects are taken into account, while the inner barrier is due to the shell effects at the vicinity of the spherical shape of the composite system. Between them, a large potential pocket exists and persists at very high angular momenta allowing the capture of very heavy ions at high excitation energies.

The half-skyrmions that appear in dense baryonic matter when skyrmions are put on crystals modify drastically hadron properties in dense medium and affect strongly the nuclear tensor forces, thereby influencing the equation of state (EoS) of dense nuclear and asymmetric nuclear matter. The matter comprising half-skyrmions has vanishing quark condensate but nonvanishing pion decay constant and could be interpreted as a hadronic dual of strong-coupled quark matter. We infer from this observation combined with certain predictions of hidden local symmetry in low-energy hadronic interactions a set of new scaling laws—called “new-BR”—for the parameters in nuclear effective field theory controlled by renormalization-group flow. They are subjected to the EoS of symmetric and asymmetric nuclear matter, and are then applied to nuclear symmetry energies and properties of compact stars. The changeover from the skyrmion matter to a half-skyrmion matter that takes place after the crossover density $n_{1/2}$ provides a simple and natural field theoretic explanation for the change of the EoS from soft to stiff at a density above that of nuclear matter required for compact stars as massive as $\sim 2.4M_{\odot }$. Crossover density in the range $1.5n_0\lesssim n_{1/2}\lesssim 2.0n_0$ was employed, and the possible skyrmion half-skyrmion coexistence or crossover near $n_{1/2}$ is discussed. The novel structure of the tensor forces and the EoS obtained with the new-BR scaling is relevant for neutron-rich nuclei and compact-star matter and could be studied in RIB (rare isotope beam) machines.

We have used a potential model to compute energies of the lowest $T$ $=$ 2 states in $A=10$ nuclei. For ${}^{10}$N, we obtain $E_p=1.81$ to 1.94 MeV.

Studies of superheavy nuclei produced in the ${}^{249}$Bk + ${}^{48}$Ca reaction were performed using the Dubna Gas Filled Recoil Separator. The cross section for the production of ${}^{293}$117 and ${}^{294}$117 isotopes was measured at five excitation energies of the ${}^{297}$117 compound nucleus ranging from 30 to 48 MeV and yielding maximum values of 1.1${}_{-0.6}^{+1.2}$ pb for the $3n$ and 2.4${}_{-1.4}^{+3.3}$ pb for the $4n$ reaction channels. Alpha emission from ${}^{281}$Rg competing with spontaneous fission ($\alpha$/SF decay probability 1:9) was observed for the first time leading to the identification of the new isotope ${}^{277}$Mt ($T_{\mathrm{SF}}\approx 5$ ms). The measured decay properties are in good agreement with those expected based on the properties of neighboring even-$Z$ and odd-$Z$ nuclei. The $\alpha$ energies and half-lives of odd-$Z$ isotopes observed in the ${}^{293}$117 and ${}^{294}$117 decay chains together with results obtained for lower-$Z$ superheavy nuclei demonstrate enhanced stability with increasing neutron number toward the predicted new magic number $N=184$.

An analysis of six different sets of experimental data indicates that infinite, neutron-proton symmetric, neutral nuclear matter has a critical temperature of $T_c=17.9\pm 0.4$ MeV, a critical density of ${\rho }_c=0.06\pm 0.01$ nucleons/fm${}^3$, and a critical pressure of $p_c=0.31\pm 0.07$ MeV/fm${}^3$. These values have been obtained by analyzing data from six different reactions studied in three experiments: two “compound nuclear” reactions, ${}^{58}\mathrm{Ni}{+}^{12}\mathrm{C}{\to }^{70}$Se and ${}^{64}\mathrm{Ni}{+}^{12}\mathrm{C}{\to }^{76}$Se (both performed at the LBNL 88-in. cyclotron); and four “multifragmentation” reactions, 1 GeV/$c$ $\pi {+}^{197}$Au (performed by the Indiana Silicon Sphere Collaboration), 1 GeV/nucleon ${}^{197}\mathrm{Au}{+}^{12}$C, 1 GeV/nucleon ${}^{139}\mathrm{La}{+}^{12}$C, and 1 GeV/nucleon ${}^{84}\mathrm{Kr}{+}^{12}$C (all performed by the Equation of State Collaboration). The charge yields of all reactions as a function of the excitation energy were fit with a version of Fisher's droplet model modified to account for the dual components of the fluid (i.e., protons and neutrons), Coulomb effects, finite-size effects, and angular momentum arising from the nuclear collisions.

We estimate the electromagnetic effect of the spectator charge on azimuthal anisotropies observed in heavy ion collisions. For peripheral $\mathrm{Pb}+\mathrm{Pb}$ reactions at the top energy of the CERN Super Proton Synchrotron, $\sqrt{s_{NN}}=17.3$ GeV, we predict this effect to bring very large distortions to the observed directed flow, $v_1$, of positive and negative pions emitted close to beam rapidity. The overall magnitude of this effect is comparable to values of $v_1$ reported by the WA98 experiment in the vicinity of target rapidity. We argue that also at lower rapidities the spectator-induced electromagnetic effect may result in the splitting of values of $v_1$ observed for positive and negative pions. Such a splitting is visible in the data reported by the STAR Collaboration from the BNL Relativistic Heavy Ion Collider Beam Energy Scan. Both effects are sensitive to the space-time scenario assumed for pion emission. Therefore, they bring new information on the collision dynamics.

The centrality dependence of $\sqrt{s_{\mathit{NN}}}$ $=$ 200 GeV $d+\mathrm{Au}$ $J/\psi$ data, measured in 12 rapidity bins that span $-2.2<y<2.4$, has been fitted using a model containing an effective absorption cross section combined with EPS09 NLO shadowing. The centrality dependence of the shadowing contribution was allowed to vary nonlinearly, employing a variety of assumptions, in an effort to explore the limits of what can be determined from the data. The impact parameter dependencies of the effective absorption cross section and the shadowing parametrization are sufficiently distinct to be determined separately. It is found that the onset of shadowing is a highly nonlinear function of impact parameter. The mid and backward rapidity absorption cross sections are compared with lower energy data and, for times of 0.05 fm/$c$ or greater, data over a broad range of collision energies and rapidities are well described by a model in which the absorption cross section depends only on time spent in the nucleus.

Empirically determined values of the nuclear volume and surface symmetry energy coefficients from nuclear masses are expressed in terms of density distributions of nucleons in heavy nuclei in the local density approximation. This is then used to extract the value of the symmetry energy slope parameter $L$. The density distributions in both spherical and well deformed nuclei calculated within microscopic framework with different energy density functionals give $L=59.0\pm 13.0$ MeV. Application of the method also helps in a precision determination of the neutron skin thickness of nuclei that are difficult to measure accurately.

We derive the subleading contributions to the two-pion–one-pion exchange and ring three-nucleon force topologies emerging at next-to-next-to-next-to-next-to-leading order in chiral effective field theory. The resulting expressions do not involve any unknown parameters. To study convergence of the chiral expansion we work out the most general operator structure of a local isospin-invariant three-nucleon force. Using the resulting operator basis with 22 independent structures, we compare the strength of the corresponding potentials in configuration space for individual topologies at various orders in the chiral expansion. As expected, the subleading contributions from the two-pion–one-pion exchange and ring diagrams are large, which can be understood in terms of intermediate excitation of the $\Delta$(1232) isobar.

The reaction ${}^{16}$O($\alpha ,{}^{20}\text{Ne}$), has been studied with beam energies from 23.0 to 29.0 MeV in 100-keV steps. Resonant states in ${}^{20}$Ne have been populated which are above the multi-$\alpha$ decay threshold and that decay via ${}^8$Be + ${}^8$Be + $\alpha$ and ${}^8$Be + ${}^{12}$C$\left(0_2^{+}\right)$. An array of four silicon-strip detectors was used for the detection of four of the five emitted $\alpha$ particles, enabling the full reconstruction of the kinematics. The normalized yields have been obtained, with indications of significant strength above 24.5 MeV arising from several possible resonances.