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We have applied 57Fe nuclear resonance vibrational spectroscopy (NRVS) for the first time to study the dynamics of Fe centers in Iron-sulfur protein crystals, including oxidized wild type rubredoxin crystals from Pyrococcus furiosus, and the MoFe protein of nitrogenase from Azotobacter vinelandii. Thanks to the NRVS selection rule, selectively probed vibrational modes have been observed in both oriented rubredoxin and MoFe protein crystals. The NRVS work was complemented by extended X-ray absorption fine structure spectroscopy (EXAFS) measurements on oxidized wild type rubredoxin crystals from Pyrococcus furiosus. The EXAFS spectra revealed the Fe-S bond length difference in oxidized Pf Rd protein, which is qualitatively consistent with the crystal structure. [ABSTRACT FROM AUTHOR]

Abstract: We continue the study of form factors of descendant operators in the sinh- and sine-Gordon models in the framework of the algebraic construction proposed in [1]. We find the algebraic construction to be related to a particular limit of the tensor product of the deformed Virasoro algebra and a suitably chosen Heisenberg algebra. To analyze the space of local operators in the framework of the form factor formalism we introduce screening operators and construct singular and cosingular vectors in the Fock spaces related to the free field realization of the obtained algebra. We show that the singular vectors are expressed in terms of the degenerate Macdonald polynomials with rectangular partitions. We study the matrix elements that contain a singular vector in one chirality and a cosingular vector in the other chirality and find them to lead to the resonance identities already known in the conformal perturbation theory. Besides, we give a new derivation of the equation of motion in the sinh-Gordon theory, and a new representation for conserved currents. [Copyright &y& Elsevier]

Highlights: [•] Fast measurement of heteronuclear coupling constants by 1D NMR. [•] Simultaneous determination of the sign and the magnitude of coupling constants. [•] Direct analysis of 1D multiplets showing Up&Down or Left&Right coupling pattern. [Copyright &y& Elsevier]

The complete iron vibrational spectrum of the five-coordinate high-spin complex [Fe(OEP)(2-MeHIm)], where OEP = octaethylporphyrinato and 2-Me Him = 2-methyl-imidazole, has been obtained by oriented single-crystal nuclear resonance vibrational spectroscopy (NRVS) data. Measurements have been made in three orthogonal directions, which provides quantitative information for all iron motion. These experimental data, buttressed by density functional theory (DFT) calculations, have been used to define the effects of the axial ligand orientation. Although the axial imidazole removes the degeneracy in the in-plane vibrations, the imidazole orientation does not appear to control the direction of the in-plane iron motion. This is in contrast to the effect of the imidazolate ligand, as defined by DFT calculations, which does have substantial effects on the direction of the in-plane iron motion. The axial NO ligand has been found to have the strongest orientational effect (Angew. Chem., Int. Ed., 2010, 49, 4400). Thus the strength of the directional properties are in the order NO > imidazolate > imidazole, consistent with the varying strength of the Fe--ligand bond. [ABSTRACT FROM AUTHOR]

Abstract: The existing Nuclear Resonance Fluorescence (NRF) setup at the facility at the Triangle Universities Nuclear Laboratory at Duke University has been extended in order to perform coincidence experiments. The new setup combines large volume detectors and high resolution HPGe detectors in a very close geometry to offer high efficiency, high energy resolution as well as high count rate capabilities at the same time. The combination of a highly efficient spectroscopy setup with the mono-energetic high-intensity photon beam of provides a worldwide unique experimental facility to investigate the pattern of dipole excitations in atomic nuclei. The performance of the new setup has been assessed by studying the nucleus 32S at 8.125MeV beam energy. The relative branching ratio from the 1+ level at 8125.4keV to the first excited 2+ state was determined to 15.7(3)%. [Copyright &y& Elsevier]

The nucleon resonances are investigated within a dynamical coupled-channels model of π N and γ N reactions up to the invariant mass W = 2 GeV. The meson-baryon (M B) channels included in the calculations are M B = π N, η N, K Λ, K Σ, and pπ N that has π Δ, ρ N, and σ N resonant components. The meson-baryon amplitudes TM'B',MB(W) are calculated from solving a set of coupled-channels integral equations defined by an interaction Hamiltonian consisting of (a) meson-exchange interactions vM'B',MB derived from phenomenological Lagrangian and (b) vertex interactions N* → M B for describing the transition of a bare excited nucleon state N* to a meson-baryon channel M B. The parameters of νM'B',MB are mainly constrained by the fit to the data of π N → π N in the low-energy region up to W= 1.4 GeV. The bare masses of N* and the N* → M B parameters are then determined in simultaneous fits to the data of π N → π N up to W = 2.3 GeV and those of π N → η N, K Λ, K Σ and γ N → π N,η N, K Λ, K Σ up to W= 2.1 GeV. The pole positions and residues of nucleon resonances are extracted by analytically continuing the meson-baryon amplitudes TM'B',MB(W) to the complex Riemann energy surface. From the extracted residues, we have determined the N* → π N,γ N,η N, K Λ, K Σ transition amplitudes at resonance poles. We compare the resonance pole positions from our analysis with those given by the Particle Data Group and the recent coupled-channels analyses by the Jülich and Bonn-Gatchina groups. Four results agree well only for the first N* in each spin-parity-isospin (JP,I) channel. For higher mass states, the number of states and their resonance positions from four results do not agree well. We discuss the possible sources of the discrepancies and the need of additional data from new hadron facilities such as the Japan Proton Accelerator Research Complex. [ABSTRACT FROM AUTHOR]

A fast and robust time-independent method to calculate thermal rate constants in the deep resonant tunneling regime for scattering reactions is presented. The method is based on the calculation of the cumulative reaction probability which, once integrated, gives the thermal rate constant. We tested our method with both continuous (single and double Eckart barriers) and discontinuous first derivative potentials (single and double rectangular barriers). Our results show that the presented method is robust enough to deal with extreme resonating conditions such as multiple barrier potentials. Finally, the calculation of the thermal rate constant for double Eckart potentials with several quasi-bound states and the comparison with the time-independent log-derivative method are reported. An implementation of the method using the Mathematica Suite is included in the Supporting Information. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The parameters of six resonances of the isobar model for η′-meson photoproduction were fitted to experimental differential cross sections for the reaction γπ → η′p that weremeasured by the CLAS-2009 and CBELSA/TAPS Collaborations (Mainz, Germany). It was shown that, in the photon energy region from the reaction threshold to 3700MeV, a good description of the experimental cross sections was attained by taking into account the contributions of high-angular-momenta heavy resonances alone. [ABSTRACT FROM AUTHOR]

The local surrounding of copper, antimony, and iodine atoms in multicomponent chalcogenide films CuI-PbI-AsSe and CuI-SbI-PbI-AsSe deposited from solutions of chalcogenide glass in n-butylamine has been studied by the Mössbauer spectroscopy method on Sb and I isotopes. It was established that antimony atoms are in the Sb (III) state, where each antimony atom is surrounded by three selenium atoms. Copper atoms are in the Cu (I) state and are surrounded by iodine atoms. The local surrounding of copper, antimony, and iodine atoms in chemically deposited chalcogenide films is analogous to the local surrounding of atoms in the initial chalcogenide glass. [ABSTRACT FROM AUTHOR]

High-valent intermediates of binuclear nonheme iron enzymes are structurally unknown despite their importance for understanding enzyme reactivity. Nuclear resonance vibrational spectroscopy combined with density functional theory calculations has been applied to structurally well-characterized high-valent mono- and di-oxo bridged binuclear Fe model complexes. Low-frequency vibrational modes of these high-valent diiron complexes involving Fe motion have been observed and assigned. These are independent of Fe oxidation state and show a strong dependence on spin state. It is important to note that they are sensitive to the nature of the Fe2 core bridges and provide the basis for interpreting parallel nuclear resonance vibrational spectroscopy data on the high-valent oxo intermediates in the binuclear nonheme iron enzymes. [ABSTRACT FROM AUTHOR]

We used nuclear resonant scattering (NRS) of synchrotron radiation to investigate the details of the thickness- induced spin reorientation transition (SRT) in ultrathin epitaxial iron films on W(110), where the thicknesses of the films ranged from 1-5 monolayers. During growth, the magnetization of the Fe film, which was probed by the hyperfine magnetic field, changes from a noncollinear configuration with an out-of-plane magnetic component to the homogeneously magnetized state with the in-plane 1-10] easy direction. The fast acquisition of the experimental NRS spectra combined with the high sensitivity of this technique to the orientation of the hyperfine magnetic fields allowed us to study the magnetic evolution during SRT in detail. Our results reveal the complex character of this transition, which has been intensively studied in the past. The noncollinear magnetic structure appears in the system of the mono-, double-, and trilayer areas that coexist due to deviation from the layer-by-layer growth of iron on W(110). We also report the observation of out-of-plane magnetic anisotropy in the double-layer areas at temperatures as high as 300 K. By comparing the experimental results with density functional theory calculations, we conclude that surface magnetic moments are enhanced by 25%. [ABSTRACT FROM AUTHOR]

We investigate the Λ(1520) hadronic production in the pp → pK+Λ(1520) and π-p K0Λ(1520) reactions within the effective Lagrangian method. For the π-p K0Λ(1520) reaction, in addition to the "background" contributions from t-channel K* exchange, μ-channel Σ+ exchange, and s-channel nucleón pole terms, we also consider the contribution from the nucleón resonance N*(2080) (spin-parity Jp = 3/2-), which has significant coupling to the KΛ(1520) channel. We show that the inclusion of the N*(2080) leads to a fairly good description of the low-energy experimental total cross section data of the π-p K0Λ(1520) reaction. From fitting to the experimental data, we get the N*(2080)Nπ coupling constant gN*(208O)/Nπ = 0.14 ± 0.04. By using this value, and with the assumption that the excitation of N*(2080) is due to the π0-meson exchanges, we calculate the total and differential cross sections of the pp → pK+Λ(1520) reaction. We also demonstrate that the invariant mass distribution and the Dalitz plot provide direct information of the Λ(1520) production, which can be tested by future experiments. [ABSTRACT FROM AUTHOR]

The first systematic study of the correlation between the experimental giant dipole resonance (GDR) width and the average deformation (β) of the nucleus at finite excitation is presented for the mass region A ~ 59 to 208. We show that the width of the GDR (Γ) and the quadrupole deformation of the nucleus do not follow a linear relation, as predicted earlier, owing to the GDR-induced quadrupole moment, and the correlation also depends on the mass of the nuclei. The different empirical values of (β) extracted from the experimental GDR width match exceptionally well with the thermal shape fluctuation model. As a result, this universal correlation between (β) and Γ provides a direct experimental probe to determine the nuclear deformation at finite temperature and angular momentum over the entire mass region. [ABSTRACT FROM AUTHOR]

Background: The resonance structure in 11C is of particular interest with regard to the astrophysical 7Be(α,γ) reaction, relevant at high temperature, and to the α-cluster structure in 11C. Purpose: The measurement was made to determine the unknown resonance parameters for the high excited states of 11C. In particular, the α-decay width can be useful information to discuss the α-cluster structure in 11C. Methods: New measurements of 7Be+α resonant scattering and the 7Be(α,p)10B reaction in inverse kinematics were performed for center-of-mass energy up to 5.5 MeV, and the resonances at excitation energies of 8.9-12.7 MeV in the compound 11C nucleus were studied. Inelastic scattering of 7Be+α and the 7Be(α,p1)10B* reaction were also studied with a simultaneous γ-ray measurement. The measurements were performed at the low-energy radioactive ion beam facility CRIB (CNS Radioactive Ion Beam separator) of the Center for Nuclear Study, the University of Tokyo. Results: We obtained excitation functions of 7Be(α,α0)7Be (elastic scattering), 7Be(α,α1)7Be* (inelastic scattering), 7Be(α,p0)10B, and 7Be(α,p1)10B*. Many resonances including a new one were observed and their parameters were determined by using an R-matrix analysis. Conclusions: The resonances we observed possibly enhance the 7Be(α,γ) reaction rate but with a smaller magnitude than the lower-lying resonances. A new negative-parity cluster band, similar to the one previously suggested in the mirror nucleus 11B, is proposed. [ABSTRACT FROM AUTHOR]

The article discusses the experimental developments in nuclear physics. It presents the extraction of nucleon resonance couplings through the use of π- photoproduction cross sections on the neutron. It explores the effect of adding the CEBAF Large Acceptance Spectrometer (CLAS) differential cross sections for ϒn → π- p to the full Scattering Analysis Interactive Dial-in (SAID) program database.

The article discusses the experimental developments in nuclear physics. It presents the study which calculated the mass shifts of 1 S, 2 S, and 1 P bottomonium states because of the coupling to the meson-meson continuum. The calculation was made within the unquenched quark model (UCQM). It claims that the baryon and meson resonances were extensively studied within the constituent quark model (CQM).

The article discusses the experimental developments in nuclear physics. It presents the study which examined the near-threshold bump structure in the forward differential cross section of the ø-meson photoproduction to find if it is a signature of resonance. The methods used in the study includes the effective Lagrangian approach.

This study sets out to explore the perception of noise, as well as the relation toward meaning or information that it might contain, in arts, science and daily life. It is realized as an installation based on a suspended cloud of nitinol drums that create a sonic environment evolving in time and space. Digital random noise drives the instruments. Roaming freely and listening, visitors become part of an ecology of noise. As visitors explore differing regions in time and space, what appears to be noise can shift to a "meaningful" signal. This process of discovering a clear signal in a noisy background holds strong analogies to the scientific search for a nuclear resonance performed in the nuClock project. [ABSTRACT FROM AUTHOR]

Continuum discretized coupled-channel (CDCC) calculations of total fusion cross sections for reactions induced by the weakly bound nucleus 6Li with targets 28Si, 59Co, 96Zr, 198Pt, and 209Bi at energies around the Coulomb barrier are presented. In the cluster structure frame of 6Li→α+d, short-range absorption potentials are considered for the interactions between the α and d fragments with the targets. The effect of resonance (l=2, Jπ=3+,2+,1+) and nonresonance states of 6Li on fusion is studied by using two approaches: (1) by omitting the resonance states from the full discretized CDCC breakup space and (2) by considering only the resonance subspace. A systematic analysis of the effect on fusion from resonance breakup couplings is carried out from light to heavy mass targets. Among other things, it is found that resonance breakup states produce strong repulsive polarization potentials that lead to fusion suppression. Couplings from nonresonance states give place to weak repulsive potentials at high energies; however, these become attractive for the heavier targets at low energies. [ABSTRACT FROM AUTHOR]

The low-lying dipole strength in 52Cr was measured in nuclear resonance fluorescence experiments using a quasimonochromatic, linearly polarized photon beam. The parities of the excited dipole states were determined by the intensity asymmetry of resonantly scattered γ rays with respect to the polarization plane of the incident photon beam. We observed 62 resonances at excitation energies between 7.5 and 12.1 MeV. The observed M1 and E1 strengths were compared via random-phase-approximation calculations using the Skyrme interaction. The effects of two-particle-two-hole configuration mixing and tensor force on dipole strength distributions were investigated. [ABSTRACT FROM AUTHOR]

Nuclear resonant x-ray diffraction in grazing incidence geometry is used to determine the lateral magnetic configuration in a one-dimensional lattice of ferromagnetic nanostripes. During magnetic reversal, strong nuclear superstructure diffraction peaks appear in addition to the electronic ones due to an antiferromagnetic order in the nanostripe lattice. We show that the analysis of the angular distribution together with the time dependence of the resonantly diffracted x rays reveals surface spin structures with very high sensitivity. This scattering technique provides unique access to laterally correlated spin configurations in magnetically ordered nanostructures and, in perspective, also to their dynamics. [ABSTRACT FROM AUTHOR]

The Porter-Thomas (PT) distribution of resonance widths is one of the oldest and simplest applications of statistical ideas in nuclear physics. Previous experimental data confirmed it quite well, but recent and more careful investigations show clear deviations from this distribution. To explain these discrepancies, Volya, Weidenmüller, and Zelevinsky [Phys. Rev. Lett. 115, 052501 (2015)] argued that to get a realistic model of nuclear resonances is not enough to consider one of the standard random matrix ensembles which leads immediately to the PT distribution, but it is necessary to add a rank-one interaction which couples resonances to decay channels. The purpose of this Letter is to solve this model analytically and to find explicitly the modifications of the PT distribution due to such an interaction. Resulting formulas are simple, in good agreement with numerics, and could explain experimental results. [ABSTRACT FROM AUTHOR]

We have examined within a fully self-consistent theoretical framework the energy difference between the anti-analog giant dipole resonance (AGDR) and the isobaric analog state (IAS), EAGDR-EIAS, as an indicator of the neutron skin and of the density behavior of the symmetry energy. We have improved two specific points in our HF+RPA calculations: (1) the exchange term of the two-body Coulomb interaction is treated exactly without Slater approximation; and (2) the two-parameters spin-orbit interaction is treated in a consistent way within the energy density functional theory. The estimated values for the neutron skin in 208Pb and the slope parameter of symmetry energy are compared with previous analysis available in the literature. [ABSTRACT FROM AUTHOR]

We present depth-resolved nuclear resonance reflectivity studies of the magnetization evolution in [57Fe(3nm)/Cr(1.2nm)]10 multilayer under applied external field. The measurements have been performed at the station BL09XU of SPring-8 at different values of the external field (0-1500 Oe). We apply the joint fit of the delayed reflectivity curves and the time spectra of the nuclear resonance reflectivity measured at different grazing angles for enhancement of the depth resolution and reliability of results. We show that the azimuth angle, which is used in all papers devoted to the magnetization profile determination, has a more complicated physical sense due to the partially coherent averaging of the scattering amplitudes from magnetic lateral domains. We describe how to select the true azimuth angle from the determined "effective azimuth angle." Finally we obtain the noncollinear twisted magnetization depth profiles where the spin-flop state appears sequentially in different 57Fe layers at increasing applied field. [ABSTRACT FROM AUTHOR]

We consider spherically symmetric Einstein-massless-scalar field equations with a negative cosmological constant in five dimensions and analyze the evolution of small perturbations of anti-de Sitter (AdS) spacetime using the recently proposed resonant approximation. We show that for typical initial data the solution of the resonant system develops an oscillatory singularity in finite time. This result hints at a possible route to establishing the instability of AdS under arbitrarily small perturbations. [ABSTRACT FROM AUTHOR]

To search for the lowest energy nuclear isomeric transition in 229Th in solid samples, a novel adsorption technique which prepares 229Th atoms on a surface of CaF2 is developed. Adsorbed 229Th is exposed to highly intensive undulator radiation in the wavelength range between 130 and 320 nm, which includes the indirectly measured nuclear resonance wavelength 160(10) nm. After the excitation, fluorescence from the sample is detected with a VUV sensitive photomultiplier tube. No clear signal relating to the nuclear transition is observed and possible reasons are discussed. [ABSTRACT FROM AUTHOR]