| 1. |
- Li, Z. S, et al.
(författare)
-
The FERRUM project: radiative lifetimes of intermediate-excitation states of Fe II measured in a fluorescence signal induced by laser pumping from a metastable state
- 1999
-
Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 6:1, s. 9-12
-
Tidskriftsartikel (refereegranskat)abstract
- A new collaborative program, the FERRUM project. aims at extending and improving the database of oscillator strengths for the astrophysical important Fe II spectrum. In this paper we report on the experimental method applied for measurements of radiative lifetimes of Fe II levels at intermediate excitation (5-10 eV) that can be populated ba laser excitation from metastable states. The technique involves a laser-produced plasma as a source for metastable ions, a stimulated Brillouin scatttering cell for shortening the laser pulse, and fast time resolved detection. We have applied the technique on two Fe II levels at about 7.5 eV and obtained the lifetimes: tau(z(4)S(3/2)(0)) = 3.8(2) ns; tau(y(4)P(5/2)(0)) = 3.6(3) Its.
|
|
| 2. |
- Adamczewski-Musch, J., et al.
(författare)
-
Production and electromagnetic decay of hyperons : a feasibility study with HADES as a phase-0 experiment at FAIR
- 2021
-
Ingår i: European Physical Journal A. - : Springer Nature. - 1434-6001 .- 1434-601X. ; 57:4
-
Tidskriftsartikel (refereegranskat)abstract
- A feasibility study has been performed in order to investigate the performance of the HADES detector to measure the electromagnetic decays of the hyperon resonances Sigma(1385)(0), Lambda(1405) and Lambda(1520) as well as the production of double strange baryon systems Xi(-) and Lambda Lambda in p + p reactions at a beam kinetic energy of 4.5GeV. The existing HADES detector will be upgraded by a new Forward Detector, which extends the detector acceptance into a range of polar angles that plays a crucial role for these investigations. The analysis of each channel is preceded by a consideration of the production cross-sections. Afterwards the expected signal count rates using a target consisting of either liquid hydrogen or polyethylene are summarized.
|
|
| 3. |
- Adlarson, Patrik, et al.
(författare)
-
Backward single-pion production in the pd -> He-3 pi(0)reaction with WASA-at-COSY
- 2018
-
Ingår i: European Physical Journal A. - : SPRINGER. - 1434-6001 .- 1434-601X. ; 54:9
-
Tidskriftsartikel (refereegranskat)abstract
- New data on the production of single neutral pions in the pd -> He-3 pi(0) reaction are presented. For fifteen proton beam momenta between p(p) = 1.60GeV/c and p(p) = 1.74 GeV/c, differential cross sections are determined over a large fraction of the backward hemisphere. Since the only previous systematic measurements of single-pion production at these energies were made in collinear kinematics, the present work constitutes a significant extension of the current knowledge on this reaction. Even this far above the production threshold, significant changes are found in the behaviour of the angular distributions over small intervals in beam momentum.
|
|
| 4. |
- Adlarson, Patrik, et al.
(författare)
-
Cross section ratio and angular distributions of the reaction p + d -> He-3 + eta at 48.8MeV and 59.8MeV excess energy
- 2014
-
Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 50:6, s. 100-
-
Tidskriftsartikel (refereegranskat)abstract
- We present new data for angular distributions and on the cross section ratio of the p+d -> He-3+eta reaction at excess energies of Q - 48.8MeV and Q - 59.8 MeV. The data have been obtained at the WASA-at-COSY experiment (Forschungszentrum Julich) using a proton beam and a deuterium pellet target. While the shape of obtained angular distributions show only a slow variation with the energy, the new results indicate a distinct and unexpected total cross section fluctuation between Q = 20MeV and Q = 60 MeV, which might indicate the variation of the production mechanism within this energy interval.
|
|
| 5. |
- Adlarson, Patrik, et al.
(författare)
-
Measurement of the (n)over-right-arrowp -> d pi(0) pi(0) reaction with polarized beam in the region of the d(*)(2380) resonance
- 2016
-
Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 52:5, s. 1-7
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a high-statistics measurement of the most basic double-pionic fusion reaction over the energy region of the d (*)(2380) resonance by use of a polarized deuteron beam and observing the double fusion reaction in the quasifree scattering mode. The measurements were performed with the WASA detector setup at COSY. The data reveal substantial analyzing powers and confirm conclusions about the d(*) resonance obtained from unpolarized measurements. We also confirm the previous unpolarized data obtained under complementary kinematic conditions.
|
|
| 6. |
- Adolfsson, J., et al.
(författare)
-
QCD challenges from pp to A–A collisions
- 2020
-
Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 56:11
-
Forskningsöversikt (refereegranskat)abstract
- This paper is a write-up of the ideas that were presented, developed and discussed at the third International Workshop on QCD Challenges from pp to A–A, which took place in August 2019 in Lund, Sweden (Workshop link: https://indico.lucas.lu.se/event/1214/). The goal of the workshop was to focus on some of the open questions in the field and try to come up with concrete suggestions for how to make progress on both the experimental and theoretical sides. The paper gives a brief introduction to each topic and then summarizes the primary results.
|
|
| 7. |
- Ahlgren Cederlöf, Ebba, et al.
(författare)
-
Lifetime measurement of the yrast 2+ state in 118Te
- 2023
-
Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 59:12
-
Tidskriftsartikel (refereegranskat)abstract
- The electromagnetic transition probabilities of the yrast 2+ states in the midshell Te isotopes, two protons above the closed shell at Sn, are of great importance for the understanding of nuclear collectivity in these isotopes and the role played by the neutron-proton interactions and cross-shell excitations. However, the large uncertainty of the experimental data for the midshell nucleus 118Te and the missing data for 116Te make it difficult to pin down the general trend of the evolution of transition probabilities as a function of the neutron number. In this work, the lifetime of the yrast 2+ state in 118Te was measured, with the aim of reducing the uncertainty of the previous measurement. The result is τ2+ = 7.46(19) ps. In addition, the lifetime of the 4+ state was measured to be τ4+ = 4.25(23) ps. The experimental transition rates are extracted from the measured lifetimes and compared with systematic large-scale shell-model calculations. The trend of the B(E2; 0+ → 2+) values in the midshell area is in good agreement with the calculations and the calculated B4/2 ratio provide evidence for 118Te as a near perfect harmonic vibrator.
|
|
| 8. |
- Ahmed, I., et al.
(författare)
-
Shell-model studies relevant for the low-energy Coulomb excitation in Zn isotopes
- 2023
-
Ingår i: European Physical Journal A. - : Springer Nature. - 1434-6001 .- 1434-601X. ; 59:12
-
Tidskriftsartikel (refereegranskat)abstract
- The low-lying nuclear structure of even-even Zn isotopes ranging from 62 Zn to 70 Zn has been comprehensively examined through large scale shell model calculations. These calculations encompassed the f 5 / 2p 3 / 2 , 1 / 2g 9 / 2 (fpg) model space without any truncation, employing 56 Ni as an inert core. Two different effective interactions, JUN45 and jj44b, were utilized in these calculations. Various critical observables, including excitation energies, reduced transition strengths, and electric quadrupole moments, were computed and then evaluated in the context of existing experimental data. The configurations of the resulting wave functions were also thoroughly analyzed. Furthermore, occupation probabilities for distinct single-particle orbitals were determined, with particular attention given to the pivotal role of the g 9 / 2 orbital in elucidating the nuclear structure of heavy Zn isotopes. Additionally, rotational invariants were calculated for the ground state, shedding light on a prolate deformation in 62 Zn and 64 Zn, while suggesting moderate prolate-triaxial excitations in 66 Zn, 68 Zn, and 70 Zn. These findings hold significant relevance for interpreting the intriguing outcomes of sub-barrier Coulomb excitation experiments, offering invaluable insights into the static electromagnetic properties of the nucleus through a model-independent approach.
|
|
| 9. |
- Ahrens, J, et al.
(författare)
-
First measurement of the helicity-dependent (gamma)over-right-arrow(p)over-right-arrow -> p eta differential cross-section
- 2003
-
Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 17:2, s. 241-244
-
Tidskriftsartikel (refereegranskat)abstract
- The helicity dependence of the (γ) over right arrow(p) over right arrow -+ peta reaction has been measured for the first time at a center-of-mass angle theta(eta)*= 70degrees in the photon energy range from 780 MeV to 790 MeV. The experiment, performed at the Mainz microtron MAMI, used a 4pi-detector system, a circularly polarized, tagged photon beam. and a longitudinally polarized frozen-spin target. The helicity 3/2 cross-section is found to be small and the results for helicity 1/2 agree with predictions from the MAID analysis.
|
|
| 10. |
- Ahrens, J, et al.
(författare)
-
Helicity dependence of the gamma p -> N pi channels and multipole analysis in the Delta region
- 2004
-
Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 21:2, s. 323-333
-
Tidskriftsartikel (refereegranskat)abstract
- A high-quality double-polarization data set for the helicity dependence of the total and differential cross-sections for both gammap --> Npi channels in the Delta region has been obtained in the framework of the GDH experiment. The experiment, performed at the Mainz microtron MAMI, used a 4pi detection system, a circularly polarized photon beam, and a longitudinally polarized frozen-spin target. These data are included in the database to perform a multipole analysis to determine the properties of the Delta(1232)-resonance. For the resonant Delta(1232) multipoles we find a very good agreement with previous analyses, while the nonresonant ones show significant deviations.
|
|
