Springer Science and Business Media LLC

The structure of 17C has been investigated using the three-neutron transfer reaction (12C,9C) on a 14C target at 231MeV incident energy, the reaction Q-value is Q 0 = - 46.930MeV. Eleven new states up to 16.3MeV excitation energy were identified. The same reaction has also been used on a 12C target ( Q 0 = - 38.787MeV), and excited states in 15C up to 19MeV were observed. In 17C the three transferred neutrons populate (sd )3 configurations on the 14C core. The comparison of levels populated by the (12C,9C) reaction in 17C, 16C and 15C reveals a strong similarity of their properties. This concerns especially nine states in each of the three carbon isotopes, which show practically the same excitation energies except a constant mean shift of +5.82MeV for 16C and +6.65MeV for 15C with respect to 17C. The triples of states from the three isotopes, which correspond to each other, have also similar widths and cross-section ratios. It is concluded that the same (sd )3 structures are populated in the three carbon isotopes. The observed levels of 17C are also compared to the levels of 19O with known assignments and to shell model calculations, and their decay properties are discussed.

Nhiều dữ liệu trong Vật lý Năng lượng Cao thực chất là trung bình mẫu. Bài báo chỉ ra rằng khi xem xét ý nghĩa chính xác của dữ liệu và loại bỏ các trạng thái bị ràng buộc yếu nhất khỏi khí cộng hưởng hadron, toàn bộ phổ của pion, kaon và proton đo được tại trung tâm tốc độ trong các va chạm Pb-Pb tại $ \sqrt{s_{NN}} = 2.76$ TeV có thể được điều chỉnh đồng thời. Các phân bố bất biến được dự đoán với sự giúp sức của mô hình đông tụ đơn trong khung cân bằng hóa học. Phương pháp này được áp dụng cho các phép đo trong các ô trung tâm của các va chạm Pb-Pb và cho kết quả điều chỉnh chấp nhận được cho tất cả các ô ngoại trừ ô ngoại biên. So sánh với các kết quả thu được trong khung thực hiện mô hình đông tụ đơn ban đầu cũng được trình bày. Một số tác động tổng quát hơn, có thể của cách tiếp cận này cũng được chỉ ra.

A non-additive entropy is used to describe quark matter. We consider a non-extensive thermodynamic system in the framework of the MIT bag model of hadrons, in order to consider the correlation between quarks and gluons due to strong interactions. The non-additive entropy of the system describes quarks and gluons as two probabilistically independent subsystems. We analyze the phase diagram in terms of the correlation parameter q that enters the sum of entropies in the Tsallis prescription. For the case of non-zero chemical potentials it can be shown that the systems with $ q\le q_{\max}$ may be associated with the weakly coupled systems while those with $q > q_{\max}$ are more correlated. Furthermore, we find that the critical temperature for the hadron increases as the correlation between quarks and gluons increases, according to the expectations.

Theoretical issues and perspectives of hadronic matter at high baryon density are discussed with focus on the restoration of chiral symmetry and observable consequences.

The low-energy structures of the radioactive nuclei 20, 21Na have been examined using Coulomb excitation at the TRIUMF-ISAC radioactive ion beam facility. Beams of ∼ 5×106 ions/s were accelerated to 1.7MeV/A and Coulomb excited in a 0.5mg/cm^2 natTi target. Two TIGRESS HPGe clover detectors perpendicular to the beam axis were used for $ \gamma$ -ray detection, while scattered nuclei were observed by the Si detector BAMBINO. For 21Na , Coulomb excitation from the 3/2+ ground state to the first excited 5/2+ state was observed, while for 20Na , Coulomb excitation was observed from the 2+ ground state to the first excited 3+ and 4+ states. For both beams, B ( $ \lambda$ L) values were determined using the 2+ $ \rightarrow$ 0+ de-excitation in 48Ti as a reference. The resulting B(E2) ↓ value for 21Na is 137±9 e^2fm^4, while the resulting B( $ \lambda$ L) ↓ values for 20Na are 55±6 e^2fm^4 for the 3+ $ \rightarrow$ 2+ , 35.7±5.7 e^2 fm^4 for the 4+ $ \rightarrow$ 2+ , and 0.154±0.030 μ_N^2 for the 4+ $ \rightarrow$ 3+ transitions. This analysis significantly improves the measurement of the 21Na B(E2) value, and provides the first experimental determination of B( $ \lambda$ L) values for the proton dripline nucleus 20Na .-1