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Träfflista för sökning "L773:0556 2813 srt2:(2020-2021)"

Sökning: L773:0556 2813 > (2020-2021)

  • Resultat 1-8 av 8
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1.
  • Adlarson, Patrik, et al. (författare)
  • Differential cross sections for neutron-proton scattering in the region of the d* (2380) dibaryon resonance
  • 2020
  • Ingår i: Physical Review C. Nuclear Physics. - : AMER PHYSICAL SOC. - 0556-2813 .- 1089-490X. ; 102:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Differential cross sections have been extracted from exclusive and kinematically complete high-statistics measurements of quasifree polarized (n) over barp scattering performed in the energy region of the d* (2380) dibaryon resonance covering the range of beam energies T-n = 0.98-1.29 GeV (root s = 2.32-2.44 GeV). The experiment was carried out with the WASA-at-COSY setup having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process dp -> np + p(spectator). In this way the np differential cross section sigma (Theta) was measured over a large angular range. The obtained angular distributions complement the corresponding analyzing power A(y)(Theta) measurements published previously. A SAID partial-wave analysis incorporating the new data strengthens the finding of a resonance pole in the coupled D-3(3) - (3)G(3) waves.
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2.
  • Adlarson, Patrik, et al. (författare)
  • Search for the eta mesic He-3 in the pd -> dp pi(0) reaction with the WASA-at-COSY facility
  • 2020
  • Ingår i: Physical Review C. Nuclear Physics. - : AMER PHYSICAL SOC. - 0556-2813 .- 1089-490X. ; 102:4
  • Tidskriftsartikel (refereegranskat)abstract
    • The excitation function for the pd -> dp pi(0) reaction has been measured byWASA-at-COSY experiment with the aim of searching for He-3-h mesic nuclei. The measurement in the vicinity of h meson production was performed using a ramped proton beam. The data analysis and interpretation was carried out with the assumption that the h mesic helium decays via the formation of an intermediate N*(1535) resonance. No direct signal of the. mesic nucleus is observed in the excitation function. We determine a new improved upper limit for the total cross section for the bound state production and decay in the pd -> (He-3-eta)(bound) -> dp pi(0) process. It varies between 13 nb to 24 nb for the bound state with width in the range Gamma is an element of ( 5, 50) MeV.
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3.
  • Georgali, E., et al. (författare)
  • Experimental study of the 165Ho(n, 2n) reaction : Cross section measurements for the population of the 164Ho ground state and isomeric state from the threshold up to 20 MeV
  • 2020
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 102:3
  • Tidskriftsartikel (refereegranskat)abstract
    • In the present work the 165Ho(n,2n) reaction was studied experimentally and theoretically for the population of the ground state (Jπ=1+) of the 164Ho product nucleus, as well as for the population of its isomeric state (Eex=139.8 keV, Jπ=6−). The cross sections of both the ground and isomeric state channels were measured at energies near the reaction threshold (Eth=8.04 MeV), at 10.1, 10.4, and 10.7 MeV, as well as at energies higher than 17 MeV, at 17.1, 18.1, 19.0, and 19.6 MeV. The adopted method was the activation technique relative to the 197Au(n,2n) 196Au and 27Al(n,α)24Na reference reactions. The quasi-monoenergetic neutron beams for the near threshold energies were produced via the 2H(d,n)3He reaction, while for the neutron beams above 17 MeV the 3H(d,n)4He reaction was utilized. In both cases the deuteron beams were delivered by the 5.5 MV Tandem Van de Graaff accelerator of the Institute of Nuclear and Particle Physics at N.C.S.R. “Demokritos”. Additional to the experimental study, calculations were performed using the talys code (v. 1.9). The experimental data of the present work along with the previous measurements were compared with the talys results so as to investigate the reproduction of the experimental data for the different level density models of the code.
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4.
  • Guo, S., et al. (författare)
  • Pseudospin partner bands in Ba-130
  • 2020
  • Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society (APS). - 0556-2813 .- 1089-490X. ; 102:4
  • Tidskriftsartikel (refereegranskat)abstract
    • The high-spin states in Ba-130 have been investigated using the Sn-122(C-13, 5n) reaction and the GALILEO array coupled to the EUCLIDES and Neutron Wall ancillary detectors. The level scheme has been extended to an excitation energy of approximate to 12 MeV and spin 28. Two sets of pseudospin partner bands have been identified built on pi h(11/2)(g(7/2), d(5/2)) and nu h(11/2)(S-1/2, d(3/2)) configurations. The assignments are supported by calculations using the projected shell model and the particle rotor model.
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5.
  • Junker, Olov, et al. (författare)
  • Electromagnetic form factors of the transition from the spin-3/2 Σ to the Λ hyperon
  • 2020
  • Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society (APS). - 0556-2813 .- 1089-490X. ; 101:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The three electromagnetic form factors for the transition from a spin-3/2 Σ* hyperon to the ground-state Λ hyperon are studied. At low energies, combinations of the transition form factors can be deduced from Dalitz decays of the  Σ* hyperon to Λ plus an electron-positron pair. It is pointed out how more information can be obtained with the help of the self-analyzing weak decay of the Λ. In particular, it is shown that these transitionform factors are complex quantities already in this kinematical region. Such measurements are feasible at hyperon factories such as, for instance, the Facility for Antiproton and Ion Research (FAIR). At higher energies, the transition form factors can be measured in electron-positron collisions. The transition form factors are related to decay distributions and differential cross sections. Using dispersion theory, the low-energy electromagneticform factors for the  Σ*-to-Λ transition are related to the pion vector form factor. The additionally required input, i.e., the two-pion–Σ*–Λ amplitudes, is determined from relativistic next-to-leading-order (NLO) baryon chiralperturbation theory, including the baryons from the octet and the decuplet. A poorly known NLO parameter is fixed to the experimental value of the Σ*→Λ γ decay width. Pion rescattering is taken into account by using dispersion theory and solving a Muskhelishvili-Omnès equation. Subtracted and unsubtracted dispersion relations are discussed. However, in view of the fact that the transition form factors are complex quantities, the current data situation does not allow for a full determination of the subtraction constants. To reduce the numberof free parameters, unsubtracted dispersion relations are used to make predictions for the transition form factors in the low-energy space- and timelike regions.
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6.
  • Rudolph, D., et al. (författare)
  • Onset of high-spin rotational bands in the N=Z nucleus 62Ga
  • 2020
  • Ingår i: Physical Review C. - : American Physical Society. - 2469-9985. ; 102:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The fusion-evaporation reaction 28Si + 40Ca at 122 MeV beam energy was used to populate high-spin states in the odd-odd N = Z nucleus 62Ga. With the combination of the Gammasphere spectrometer and the Microball CsI(Tl) charged-particle detector array the decay scheme of 62Ga was extended beyond 10 MeV excitation energy. The onset of band structures was observed. These high-spin rotational states are interpreted and classified by means of cranked Nilsson-Strutinsky calculations.
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7.
  • Rudolph, D., et al. (författare)
  • Single-particle and collective excitations in the N=28 isotones 54Fe and 53Mn
  • 2020
  • Ingår i: Physical Review C. - : American Physical Society. - 2469-9985. ; 102:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The fusion-evaporation reaction 32S + 28Si at 125 MeV beam energy was used to populate high-spin states in the semimagic N = 28 nuclei 53Mn and 54Fe. With a combination of the Gammasphere spectrometer and ancillary devices including the Microball CsI(Tl) array, extensive high-spin level schemes are derived. They exhibit rotational-like collective structures and competing single-particle excitations. The experimental results are compared with predictions from shell-model calculations, for which the inclusion of isopin-symmetry-breaking terms is found to improve the description. An interpretation of the high-spin states is put forward using cranked Nilsson-Strutinsky calculations, indicative of contributions from collective excitations beyond some 8-MeV excitation energy and highlighting the importance of the g9/2 intruder orbital in this energy range.
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8.
  • Zhang, Wei, et al. (författare)
  • Identification of excited states in Te55 52107
  • 2021
  • Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society. - 0556-2813 .- 1089-490X. ; 104:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Excited states in the extremely neutron-deficient nucleus Te107 have been identified from two separate experiments using the recoil-decay tagging technique. Two connected structures were observed on the basis of γγ-coincidence relations and tentatively assigned as built on the mixed-parentage νg7/2d5/2 and νh11/2 intruder configurations. The observed structures were compared with large-scale shell-model calculations and total Routhian surface calculations. Collective behavior was discovered to persist in the νh11/2 band of Te107 which highlights the shape-polarizing effect of a single valence neutron occupying the h11/2 intruder orbit as the N=50 shell closure is approached.
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  • Resultat 1-8 av 8

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