Properties of isoscalar-pair condensates Van Isacker, P.; Macchiavelli, A. O.; Fallon, P. ...
Physical review. C,
08/2016, Letnik:
94, Številka:
2
Journal Article
Recenzirano
Odprti dostop
It is pointed out that the ground state of $n$ neutrons and $n$ protons in a single-$j$ shell,interacting through an isoscalar ($T=0$) pairing force, is not paired, $J=0$, but rather spin-aligned, ...$J=n$.This observation is explained in the context of a model of isoscalar $P$ ($J=1$) pairs,which is mapped onto a system of $p$ bosons, leading to an approximate analytic solutionof the isoscalar-pairing limit in $jj$ coupling.
Weak binding effects on the structure of $$^{40}$$Mg Macchiavelli, A. O.; Crawford, H. L.; Fallon, P. ...
The European physical journal. A, Hadrons and nuclei,
04/2022, Letnik:
58, Številka:
4
Journal Article
The Active Target Time Projection Chamber (AT-TPC) project at the National Superconducting Cyclotron Laboratory (NSCL) is a novel Active Target designed to study nuclear reactions induced by ...low-intensity exotic beams. The AT-TPC acts as a tracking medium and target at the same time, providing excellent angular (1°) and energy resolution (3% FWHM) and high luminosity. The AT-TPC offers a broad range of applications within the low-energy nuclear physics domain. Resonant scattering and transfer reactions are typically performed with Active Targets using beams with energies spanning from 1 to 10AMeV and with intensities as low as 100 pps. The AT-TPC is also a promising tool for experiments where the observables of interest require higher beam energies (above 100AMeV). In particular, inelastic scattering reactions on light targets, where the recoil particle has a very low kinetic energy (less than 1 MeV), can be performed with such a device. In this work, we discuss aspects of the AT-TPC experimental program, focusing on experiments that leverage the outstanding capabilities this detector offers. In addition, we introduce a conceptual design for a new Time Projection Chamber detector for specific measurements of reactions using special gases as targets.
An approximate solution at the critical point of the pairing transition from harmonic vibration to deformed rotation in gauge space is found by analytic solution of the collective pairing ...Hamiltonian. The eigenvalues are expressed in terms of the zeros of Bessel functions of integer order. The results are compared to the pairing bands based on the Pb isotopes.
Four previously known rotational bands in 76Rb have been extended to moderate spins using the Gammasphere and Microball γ ray and charged particle detector arrays and the 40Ca(40Ca, 3pn) reaction at ...a beam energy of 165 MeV. The properties of two of the negative-parity bands can only readily be interpreted in terms of the highly successful Cranked Nilsson–Strutinsky model calculations if they have the same configuration in terms of the number of g9/2 particles, but they result from different nuclear shapes (one near-oblate and the other near-prolate). These data appear to constitute a unique example of shape coexisting structures at medium spins.
We analyze a recent study of the one-proton knockout reaction on N-19 in the framework of a time-dependent two-level model. Focusing on the specific case of C-18, we quantify the validity of the ...so-called "piston" mechanism in terms of the timescales involved in the process, namely, the reaction time, the period of oscillation between the mixed states, and the lifetime of the excited unbound state.
Weak binding effects on the structure of 40Mg Macchiavelli, A. O.; Crawford, H. L.; Fallon, P. ...
The European physical journal. A, Hadrons and nuclei,
12/4, Letnik:
58, Številka:
4
Journal Article
Recenzirano
Odprti dostop
While the phenomenon of one- and two-neutron ground-state halo nuclei is well established, the effects of weak binding on nuclear excitation properties remain largely unexplored. Motivated by this ...question and by recent data in
40
Mg we investigate the coupling of weakly bound (halo) valence neutrons to a core using the known properties of
40
Mg to explore and illustrate possible particle-core coupling schemes and their impact on the low-lying excitation spectrum.
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