The Low Energy Beam and Ion Trap (LEBIT) Penning trap mass spectrometer was used to perform an improved-precision mass measurement of ${}^{72}\mathrm{Br}$ and the low-lying isomeric state, ${}^{72m}\mathrm{Br},$ giving mass excesses of $-59062.2\left(1.0\right)\mathrm{keV}$ and $-58960.9\left(1.2\right)\mathrm{keV}$, respectively. These values are consistent with the values from the 2012 atomic mass evaluation [Chin. Phys. C 36, 1603 (2012)] and the Nubase2012 evaluation of nuclear properties [Chin. Phys. C 36, 1157 (2012)]. The uncertainties on the mass of the ground state and isomeric state have been reduced by a factor of seven.

Neutral current quasielastic (anti)neutrino scattering cross sections on a ${}^{12}\mathrm{C}$ target are analyzed using a realistic spectral function $S(p,E)$ that gives a scaling function in accordance with the $(e,e^{\prime })$ scattering data. The spectral function accounts for the nucleon-nucleon (NN) correlations by using natural orbitals from the Jastrow correlation method and has a realistic energy dependence. The standard value of the axial mass $M_A=1.032$ GeV is used in all calculations. The effect of the final-state interaction on the spectral and scaling functions, as well as on the cross sections, is accounted for. A comparison of the calculations with the empirical data of the MiniBooNE and BNL experiments is performed. Our results are analyzed in comparison with those when NN correlations are not included and, also, with results from other theoretical approaches, such as the relativistic Fermi gas, the relativistic mean field, and the relativistic Green's function, as well as with the SuperScaling Approach based on the analysis of quasielastic electron scattering.

Using the VISHNU hybrid model, we calculate the multiplicity, spectra, and elliptic flow of $\Lambda ,\Xi$, and $\Omega$ in $2.76A$ TeV Pb + Pb collisions. Comparisons between our calculations and the ALICE measurements show that the model generally describes the soft hadron data of these strange and multistrange hadrons at several centrality bins. Mass ordering of elliptic flow among $\pi ,K,p,\Lambda ,\Xi$, and $\Omega$ has also been studied and discussed. With a nice description of the particle yields, we explore chemical and thermal freeze-out of various hadrons species at the Large Hadron Collider within the framework of the VISHNU hybrid model.

Tetraphenyl-butadiene is the wavelength shifter most widely used in combination with liquid argon. The latter emits scintillation photons with a wavelength of 127 nm that need to be downshifted to be detected by photomultipliers with glass or quartz windows. Tetraphenyl-butadiene has been demonstrated to have an extremely high conversion efficiency, possibly higher than 100% for 127 nm photons, while there is no precise information about the time dependence of its emission. It is usually assumed to be exponentially decaying with a characteristic time of the order of one ns, as an extrapolation from measurements with exciting radiation in the near UV. This work shows that tetraphenyl-butadiene, when excited by 127 nm photons, re-emits photons not only with a very short decay time, but also with slower ones due to triplet states de-excitations. This fact can strongly contribute to clarifying the anomalies in liquid-argon scintillation light reported in the literature since the 1970s, namely, the inconsistency in the measured values of the long decay time constant and the appearance of an intermediate component. Similar effects should be also expected when the TPB is used in combination with helium and neon, which emit scintillation photons with wavelengths shorter than 127 nm.

Although the modern shell-model picture of atomic nuclei is built from single-particle orbits with good total angular momentum $j$, leading to $j-j$ coupling, decades ago phenomenological models suggested that a simpler picture for $0p$-shell nuclides can be realized via coupling of the total spin $S$ and total orbital angular momentum $L$. I revisit this idea with large-basis, no-core shell-model calculations using modern ab initio two-body interactions and dissect the resulting wave functions into their component $L$- and $S$-components. Remarkably, there is broad agreement with calculations using the phenomenological Cohen-Kurath forces, despite a gap of nearly 50 years and six orders of magnitude in basis dimensions. I suggest that $L-S$ decomposition may be a useful tool for analyzing ab initio wave functions of light nuclei, for example, in the case of rotational bands.

A simple ${\left(sd\right)}^3$ shell-model calculation has previously worked extremely well in predicting absolute energies of the lowest $5/2^{+}$ state in ${}^{19}\mathrm{O},{}^{17}\mathrm{C}$, and ${}^{13}\mathrm{Be}$. Here, I apply the same model to ${}^{15}\mathrm{Be}$. When combined with a recent experimental result, the analysis produces tight constraints on the $s$ and $d$ single-particle energies in ${}^{13}\mathrm{Be}$.

The standard model (SM) of particle physics is spectacularly successful, yet the measured value of the muon anomalous magnetic moment ${(g-2)}_{\mu }$ deviates from SM calculations by $3.6\sigma .$ Several theoretical models attribute this to the existence of a “dark photon,” an additional U(1) gauge boson, which is weakly coupled to ordinary photons. The PHENIX experiment at the Relativistic Heavy Ion Collider has searched for a dark photon, $U$, in ${\pi }^0,\eta \to \gamma e^{+}{e}^{-}$ decays and obtained upper limits of $\mathcal{O}(2\times {10}^{-6})$ on $U-\gamma$ mixing at 90% C.L. for the mass range $30<m_U<90$ $\mathrm{MeV}/c^2$. Combined with other experimental limits, the remaining region in the $U-\gamma$ mixing parameter space that can explain the ${(g-2)}_{\mu }$ deviation from its SM value is nearly completely excluded at the 90% confidence level, with only a small region of $29<m_U<32$ $\mathrm{MeV}/c^2$ remaining.

Bulk and decay properties, including deformation energy curves, charge mean square radii, Gamow–Teller (GT) strength distributions and $\beta$-decay half-lives are studied in neutron-deficient even-even and odd-$A$ Hg and Pt isotopes. The nuclear structure is described microscopically from deformed quasiparticle random-phase approximation calculations with residual interactions in both particle-hole and particle-particle channels, performed on top of a self-consistent deformed quasiparticle Skyrme Hartree–Fock basis. The observed sensitivity of the not-yet-measured GT strength distributions to deformation is proposed as an additional complementary signature of the nuclear shape. The $\beta$-decay half-lives resulting from these distributions are compared to experiment to demonstrate the ability of the method.

In the present work, we have investigated an extension of the effective nucleon-nucleon Gogny interaction in which the zero-range density-dependent term has been replaced with a finite-range term. The parameters have been adjusted on both nuclear-matter properties and a few observables of stable nuclei. The traditional and unified fitting procedure of the Gogny force used in Bruyères-le-Châtel ensures common basic properties between the extended analytical form of the Gogny interaction, called $D2$, and the original one. In particular, symmetric infinite nuclear-matter and neutron-matter properties as well as pairing correlations have been investigated. A few static properties obtained in finite nuclei using the Hartree-Fock-Bogoliubov approach and the $D2$ parametrization of the Gogny interaction are analyzed and compared to the results obtained with $D1$-type parametrizations and experiment when it is possible. The $D2$ parametrization makes it possible to reproduce nuclear structure properties with improved accuracy.

For a shape-soft nucleus, the deformation change with increasing angular momentum of rotation can be significant. Total-Routhian-surface (TRS) calculations include the shape changes, but angular momentum is not conserved (neither is it a good quantum number, nor is it kept unchanged in the whole TRS mesh). In the projected shell model (PSM), the angular momentum appears as a good quantum number, but calculations have usually been performed with fixed deformation. In the present work, by performing angular-momentum projection on the mean-field potential-energy surface (PES), we can obtain an angular-momentum-conserved PES which gives deformation for a rotational state at a given spin. In order to investigate the shape-changing effect, we have chosen neutron-deficient Hg and Pb isotopes in which shape coexistence occurs. We interpret the irregular rotational behavior of the oblate bands at low spin as arising from deformation changes which are induced by collective rotation. At higher spin, the oblate rotational spectrum can also be influenced by the crossing between the $K=0$ ground-state band and a low-$K$ two-quasineutron band. Calculated $g$ factors for the states of oblate bands are given for future experimental testing, and the intrinsic structures of high-$K$ oblate states are investigated.

The low-energy structure of the neutron-rich nucleus ${}^{68}\mathrm{Ni}$ has been investigated by measuring the $\beta$ decay of the low-spin isomer in ${}^{68}\mathrm{Co}$ selectively produced in the decay chain of ${}^{68}\mathrm{Mn}$. A revised level scheme has been built based on the clear identification of $\beta -\gamma -E0$ delayed coincidences. Transitions between the three lowest-lying $0^{+}$ and $2^{+}$ states are discussed on the basis of measured intensities or their upper limits for unobserved branches and state-of-the-art shell model calculations.

I formulate a many-body theory to calculate the cross section of direct radiative neutron capture reaction by means of the Hartree–Fock–Bogoliubov mean-field model and the continuum quasiparticle random-phase approximation (QRPA). A focus is put on very-neutron-rich nuclei and low-energy neutron kinetic energy in the range from 1 keV to several MeV, which is relevant to the rapid neutron capture process of nucleosynthesis. I begin with the photoabsorption cross section and the $E1$ strength function. Next, in order to apply the reciprocity theorem, I decompose the cross section into partial cross sections corresponding to different channels of one- and two-neutron emission decays of photo-excited states. A numerical example is shown for the photo-absorption of ${}^{142}\mathrm{Sn}$ and the neutron capture of ${}^{141}\mathrm{Sn}$.

We analyze the production cross sections and isotopic distributions of projectilelike residues in the reactions ${}^{112}\mathrm{Sn}+{}^{112}\mathrm{Sn}$ and ${}^{124}\mathrm{Sn}+{}^{124}\mathrm{Sn}$ at an incident beam energy of 1 GeV/nucleon measured with the fragment separator at the GSI laboratory. Calculations within the statistical multifragmentation model for an ensemble of excited sources were performed with ensemble parameters determined previously for similar reactions at 600 MeV/nucleon. The obtained good agreement with the experiment establishes the universal properties of the excited spectator systems produced during the dynamical stage of the reaction. It is furthermore confirmed that a significant reduction of the symmetry-energy term at the freeze-out stage of reduced density and high temperature is necessary to reproduce the experimental isotope distributions. A trend of decreasing symmetry energy for large neutron-rich fragments of low excitation energy is interpreted as a nuclear-structure effect.

The density distributions of ${}^{10}\mathrm{Be}$ and ${}^{11}\mathrm{Be}$ nuclei obtained within the quantum Monte Carlo model and the generator coordinate method are used to calculate the microscopic optical potentials (OPs) and cross sections of elastic scattering of these nuclei on protons and ${}^{12}\mathrm{C}$ at energies $E<100$ MeV/nucleon. The real part of the OP is calculated using the folding model with the exchange terms included, while the imaginary part of the OP that reproduces the phase of scattering is obtained in the high-energy approximation. In this hybrid model of OP the free parameters are the depths of the real and imaginary parts obtained by fitting the experimental data. The well-known energy dependence of the volume integrals is used as a physical constraint to resolve the ambiguities of the parameter values. The role of the spin-orbit potential and the surface contribution to the OP is studied for an adequate description of available experimental elastic scattering cross-section data. Also, the cluster model, in which ${}^{11}\mathrm{Be}$ consists of a $n$-halo and the ${}^{10}\mathrm{Be}$ core, is adopted. Within the latter, the breakup cross sections of ${}^{11}\mathrm{Be}$ nucleus on ${}^9\mathrm{Be},{}^{93}\mathrm{Nb},{}^{181}\mathrm{Ta}$, and ${}^{238}\mathrm{U}$ targets and momentum distributions of ${}^{10}\mathrm{Be}$ fragments are calculated and compared with the existing experimental data.

Within the multiple scattering formulation, the incoherent pion production in neutrino-deuteron reactions at energies near the $\Delta \left(1232\right)$ resonance is investigated. The calculations include an impulse term and one-loop contributions from nucleon-nucleon $\left(NN\right)$ and pion-nucleon $\left(\pi N\right)$ final-state interactions. The input amplitudes of $\pi N$ scattering and electroweak pion-production reaction on the nucleon are generated from a dynamical model, which describes very extensive data of $\pi N$ scattering and both the electromagnetic and the weak pion-production reactions on the nucleon. The $NN$ scattering amplitudes are generated from the Bonn potential. The validity of the calculational procedures is established by giving a reasonably good description of the data of pion photoproduction on the deuteron. The constructed model is then applied to predict the cross sections of $\nu +d\to {\mu }^{-}+{\pi }^{+}+n+p$ and $\nu +d\to {\mu }^{-}+{\pi }^0+p+p$ reactions. The importance of including the $NN$ final-state interactions to understand the experimental data of these neutrino-deuteron reactions is demonstrated. Our results strongly suggest that the spectator approximation used in the previous analyses to extract the pion-production cross sections on the nucleon from the data on the deuteron is not valid for the $\nu +d\to {\mu }^{-}+{\pi }^{+}+n+p$, but is a good approximation for $\nu +d\to {\mu }^{-}+{\pi }^0+p+p$.

The relativistic scattering of spin-0 bosons by spherically symmetric Coulomb fields is analyzed in detail with an arbitrary mixing of vector and scalar couplings. It is shown that the partial wave series reduces the scattering amplitude to the closed Rutherford formula exactly when the vector and scalar potentials have the same magnitude, and as an approximation for weak fields. The behavior of the scattering amplitude near the conditions that furnish its closed form is also discussed. Strong suppressions of the scattering amplitude when the vector and scalar potentials have the same magnitude are observed either for particles or antiparticles with low incident momentum. We point out that such strong suppressions might be relevant in the analysis of the scattering of fermions near the conditions for the spin and pseudospin symmetries. From the complex poles of the partial scattering amplitude the exact closed forms of bound-state solutions for both particles and antiparticles with different scenarios for the coupling constants are obtained. Perturbative breaking of the accidental degeneracy appearing in a pair of special cases is related to the nonconservation of the Runge-Lenz vector.

We perform a global analysis of searches for the permanent electric dipole moments (EDMs) of the neutron, neutral atoms, and molecules in terms of six leptonic, semileptonic, and nonleptonic interactions involving photons, electrons, pions, and nucleons. By translating the results into fundamental charge-conjugation-parity symmetry (CP) violating effective interactions through dimension six involving standard model particles, we obtain rough lower bounds on the scale of beyond the standard model CP-violating interactions ranging from 1.5 TeV for the electron EDM to 1300 TeV for the nuclear spin-independent electron-quark interaction. We show that planned future measurements involving systems or combinations of systems with complementary sensitivities to the low-energy parameters may extend the mass reach by an order of magnitude or more.

Searches for Lorentz violation were recently extended to the weak sector, in particular neutron and nuclear $\beta$ decay [Noordmans, Wilschut, and Timmermans, Phys. Rev. C 87, 055502 (2013)]. From experiments on forbidden $\beta$-decay transitions, strong limits in the range of ${10}^{-6}$ to ${10}^{-8}$ were obtained on Lorentz-violating components of the $W$-boson propagator [Noordmans, Wilschut, and Timmermans, Phys. Rev. Lett. 111, 171601 (2013)]. In order to improve on these limits, strong sources have to be considered. In this Brief Report we study isotopes that undergo orbital electron capture and allow experiments at high decay rates and low dose. We derive the expressions for the Lorentz-violating differential decay rate and discuss the options for competitive experiments and their required precision.

Background: In the absence of accurate data on the free two-body hyperon-nucleon interaction, the spectra of hypernuclei provides information on the details of the effective hyperon-nucleon interaction.

Purpose: To obtain a high-resolution binding-energy spectrum for the ${}^9\mathrm{Be}(e,e^{\prime }{K}^{+}){}_{\Lambda }{}^9\mathrm{Li}$ reaction.

Method: Electroproduction of the hypernucleus ${}_{\Lambda }{}^9\mathrm{Li}$ has been studied for the first time with sub-MeV energy resolution in Hall A at Jefferson Lab on a ${}^9\mathrm{Be}$ target. In order to increase the counting rate and to provide unambiguous kaon identification, two superconducting septum magnets and a ring imaging Cherenkov detector were added to the Hall A standard equipment.

Results: The cross section to low-lying states of ${}_{\Lambda }{}^9\mathrm{Li}$ is concentrated within 3 MeV of the ground state and can be fit with four peaks. The positions of the doublets agree with theory while a disagreement could exist with respect to the relative strengths of the peaks in the doublets. The $\Lambda$ separation energy, $B_{\Lambda }$, of $8.36\pm 0.08$ (stat.) $\pm 0.08$ (syst.) MeV was measured, in agreement with an earlier experiment.