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[en] The analyzing powers for proton elastic scattering (ppA→pX) and neutron charge exchange (nnA→pX) reactions on nuclei have been measured on C, CH, CH and Cu targets at incident neutron momenta 3.0-4.2 GeV/c by detecting one charged particle in forward direction. The polarized neutron measurements are the first of their kind. The experiment was performed using the Nuclotron accelerator in JINR Dubna, where polarized neutrons and protons were obtained from break-up of a polarized deuteron beam which has a maximum momentum of 13 GeV/c. The polarimeter ALPOM2 was used to obtain the analyzing power dependence on the transverse momentum of the final-state nucleon. These data have been used to estimate the figure of merit of a proposed experiment at Jefferson Laboratory to measure the recoiling neutron polarization in the quasi-elastic H(e,e′n) reaction, which yields information on the charge and magnetic elastic form factors of the neutron.
[en] The magnetic dipole moments of the spin-32 doubly charmed, bottom and charmed-bottom baryons are obtained by means of the light-cone QCD sum rule. The magnetic dipole moments of these baryons encode essential knowledge of their inner structure and shape deformations. The numerical results are given by μ=2.94±0.95, μ=-0.67±0.11, μ=-0.52±0.07, μ=2.30±0.55, μ=-1.39±0.32, μ=-1.56±0.33, μ=2.63±0.82, μ=-0.96±0.32 and μ=-1.11±0.33, respectively.
[en] The rate of the Al(p, γ)Si reaction is one of the few key remaining nuclear uncertainties required for predicting the production of the cosmic γ-ray emitter Al in explosive burning in novae. This reaction rate is dominated by three key resonances (J = 0, 1 and 3) in Si. Only the 3 resonance strength has been directly constrained by experiment. A high resolution measurement of the Mg(d, p) reaction was used to determine spectroscopic factors for analog states in the mirror nucleus, Mg. A first spectroscopic factor value is reported for the 0 state at 6.256 MeV, and a strict upper limit is set on the value for the 1 state at 5.691 MeV, that is incompatible with an earlier (He, He) study. These results are used to estimate proton partial widths, and resonance strengths of analog states in Si contributing to the Al(p, γ)Si reaction rate in nova burning conditions.
[en] In the past 85 years the number of known nuclides increased by more than a factor of ten, resulting in 4000 presently known isotopes of 118 elements. This considerable progress we owe to the discovery of new reaction types along with the development of powerful accelerators and experimental techniques for separation and identification of reaction products. Model predictions indicate that still about 4000 further nuclides are waiting for their discovery. The vastest unexplored territory is located on the neutron-rich side in the upper half of the chart of nuclides and hides the answers to some of the most fundamental questions of nuclear physics like the limits of nuclear stability, element synthesis in the universe or stellar evolution. The access to these nuclei is presently limited by available beam intensities and/or the lack of appropriate methods for their production and identification. The latter concerns particularly new neutron-rich isotopes of transuranium and superheavy elements. To extend this area, the hope is presently based on multinucleon transfer reactions and on the application of fusion reactions with radioactive ion beams. But how promising are these approaches? Based on a survey of present-day knowledge, we treat the questions where we currently are on our journey towards new territory on the chart of nuclides, how the chances are to gain new territory in the future and which challenges we will have to face.
[en] Rotational bands built on positive parity s, d, and g valence neutron orbitals in Xe have been investigated via in-beam γ ray spectroscopy. Excited states belonging to these one-quasineutron bands were populated via Sn(Be,4nγ) fusion-evaporation reaction at a beam energy of 48 MeV. The level scheme has been updated by extending the low-lying rotational bands up to higher spin states, as well as, by assigning the spin/parity of the constituting energy levels. Signature splitting of low-js, d and high-jg bands have been discussed in comparison to the neighbouring nuclei. Theoretical Modified Particle Rotor Model (MPRM) calculations have been carried out in order to study the microscopic structure of these bands.
[en] Hadronization is known as the nonperturbative part of hadron production process which is described by the process-independent fragmentation functions. These functions refer to the probability densities for the initial partons to fragment into observed hadrons carrying away the momentum fractions of parent partons. In this work, using the quark-diquark approximative model we compute the fragmentation density of gluon into polarized triply heavy baryon Ω in a vector cc-diquark fragmentation. To impose the polarization effect of baryon into the corresponding fragmentation function we shall apply three different scenarios and compare all results.
[en] Vector-analyzing powers, A and A, of the proton-deuteron break-up reaction have been measured by using a polarized-proton beam at 135 MeV impinging on a liquid-deuterium target. For the experiment, the big instrument for nuclear-polarization analysis (BINA) was used at KVI, Groningen, the Netherlands. The data are compared to the predictions of Faddeev calculations using state-of-the-art two- and three-nucleon potentials. Our data are reasonably well described by calculations for the kinematical configurations at which the three-nucleon force (3NF) effect is predicted to be small. However, striking discrepancies are observed at specific configurations, in particular in the cases of symmetric configurations, where the relative azimuthal angle between the two protons is small which corresponds to the d(, He)n channel. The vector-analyzing powers of these configurations are compared to the proton-deuteron elastic scattering to study the spin-isospin sensitivity of the 3NF models. The results are compared to the earlier results of the proton-deuteron break-up reaction at 190 MeV proton-beam energy. Disagreement is observed for both proton-beam energies between data and calculations which points to a deficiency in the treatment of spin-isospin part of the 3NF.
[en] Excited states in the extremely neutron-deficient nucleus Pt were populated via Ru(Kr,2p) and Mo(Kr,3n) reactions. The level scheme has been extended up to an excitation energy of ≈5 MeV and tentative spin-parity assignments up to I=18. Linear polarization and angular distribution measurements were used to determine the electromagnetic E1 character of the dipole transitions connecting the positive-parity ground-state band with an excited side-band, firmly establishing it as a negative-parity band. The lowest member of this negative-parity structure was firmly assigned spin-parity 3. In addition, we observed an E3 transition from this 3 state to the ground state, providing direct evidence for octupole collectivity in Pt. Large-scale shell model (LSSM) and total Routhian surface (TRS) calculations have been performed, supporting the interpretation of the 3 state as a collective octupole-vibrational state.
[en] The first quasi‐binary acetonitriletriide Sr[CN] has been synthesised and characterised. The nearly colourless crystals were obtained from the reaction of Sr metal, graphite, and elemental N, generated by decomposition of Sr(N), in a sealed Ni ampoule with the aid of an alkali metal flux. The structure of this compound was analysed via single‐crystal X‐ray diffraction and the identity of the [CN] anion was confirmed by Raman spectroscopy and further investigated by quantum‐chemical methods. Computed interatomic distances within the [CN] anion strikingly match the obtained experimental data. (© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)