The University of Osaka · Physics and Astronomy
Professor Z. Yang's research lab specializes in experimental nuclear physics, with a focus on exotic and neutron-rich nuclei, cluster structures, and quantum many-body phenomena in atomic nuclei. The lab investigates nuclear clustering, halo structures, and collective excitations using advanced reaction techniques such as quasifree knockout, inelastic scattering, and inverse kinematics. Key research directions include the formation of α clusters and molecular-like states in light to medium-mass nuclei, the role of neutron skins in clustering, and the interplay between cluster formation and nuclear deformation or pairing correlations.
Figures are computed from collected data and may differ slightly.
In a recent breakup-reaction experiment using a Be12 beam at 29 MeV/nucleon, the 0+ band head of the expected He4+He8 molecular rotation was clearly identified at about 10.3 MeV, from which a large monopole matrix element of 7.0±1.0 fm2 and a large cluster-decay width were determined for the first time. These findings support the picture of strong clustering in Be12, which has been a subject of intense investigations over the past decade. The results were obtained thanks to a specially arranged
The surface of neutron-rich heavy nuclei, with a neutron skin created by excess neutrons, provides an important terrestrial model system to study dilute neutron-rich matter. By using quasi-free α cluster-knockout reactions, we obtained direct experimental evidence for the formation of α clusters at the surface of neutron-rich tin isotopes. The observed monotonous decrease of the reaction cross sections with increasing mass number, in excellent agreement with the theoretical prediction, implies a
A kinematically complete quasifree (p,pn) experiment in inverse kinematics was performed to study the structure of the Borromean nucleus ^{17}B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for 1s_{1/2} and 0d_{5/2} orbitals, and a surprisingly small percentage of 9(2)% was determined for 1s_{1/2}. Our finding of such a small 1s_{1/2} component and the halo features reported in p
An inelastic excitation experiment was performed with a $^{12}\mathrm{Be}$ beam at 29 MeV/u on a carbon target. New resonances close to the respective cluster separation thresholds were observed in $^{12}\mathrm{Be}$ for the $^{4}\mathrm{He}+^{8}\mathrm{He}$ and $^{6}\mathrm{He} + ^{6}\mathrm{He}$ decay channels, confirming the previously proposed molecular rotational bands. Using the model-independent angular correlation analysis, a ${0}^{+}$ spin parity is assigned to the remarkably large peak
We report here the first observation of the 0_{2}^{+} state of ^{8}He, which has been predicted to feature the condensatelike α+^{2}n+^{2}n cluster structure. We show that this state is characterized by a spin parity of 0^{+}, a large isoscalar monopole transition strength, and the emission of a strongly correlated neutron pair, in line with theoretical predictions. Our finding is further supported by the state-of-the-art microscopic α+4n model calculations. The present results may lead to new i
An overall irradiation and calibration technique was introduced and applied to a test scintillation detector array. An integral conversion method was used to reduce the nonlinearity of the time difference spectrum, and to improve the position determination especially for positions close to the two ends of a long scintillation bar. An overall position resolution of about 3.0 cm (FWHM) was extracted from the residual analysis method and verified by a direct measurement. Energy calibration was also
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