兰州大学机构库研究单元&专题: 核科学与技术学院
http:///ir.lzu.edu.cn/:80/handle/262010/113465
2024-03-29T12:35:13Z
2024-03-29T12:35:13Z
Study on branching ratios and direct CP asymmetries of D → PV decays
Qin, Qin
Li, Hsiang-Nan
Lü, Cai-Dian
Yu, Fu-Sheng
http:///ir.lzu.edu.cn/:80/handle/262010/583822
2024-03-15T02:33:05Z
2024-03-15T02:33:04Z
题名: Study on branching ratios and direct CP asymmetries of D → PV decays
作者: Qin, Qin; Li, Hsiang-Nan; Lü, Cai-Dian; Yu, Fu-Sheng
摘要: We study the non-leptonic two-body decays of D mesons decaying into one pseudoscalar meson (P) and one vector meson (V) in the factorization-asisted topological-amplitude approach. In this approach, the decay amplitudes are factorized into two parts, the short-distance contribution (Wilson coefficients) and the long-distance contribution (hadronic matrix elements). We predict the branching ratios of D → PV decays using a global fit with the non-perturbative parameters. Our results agree well with the experimental data. We also predict the direct CP asymmetries by combining short-distance dynamics associated with penguin operators and long-distance hadronic matrix elements determined by branching ratios. The large asymmetries in D+ → π+ρ0 and Ds+ → K+ may be measurable in the LHCb and future Belle II experiments. © The Authors.
2024-03-15T02:33:04Z
Molecular states with two heavy quarks
Li, Ning
Sun, Zhi-Feng
Liu, Xing
Zhu, Shi-Lin
http:///ir.lzu.edu.cn/:80/handle/262010/583821
2024-03-15T02:33:03Z
2024-03-15T02:33:02Z
题名: Molecular states with two heavy quarks
作者: Li, Ning; Sun, Zhi-Feng; Liu, Xing; Zhu, Shi-Lin
摘要: Within the one-boson-exchange (OBE) potential model, we perform a coupled-channel study of the possible deuteron-like molecular states with two heavy flavor quarks. In our study, we take into account the S-D mixing and the coupled-channel effect in the flavor space. Interestingly, we predict some molecular states which are suggested to be searched for in the further experiments. © The Authors.
2024-03-15T02:33:02Z
The initial single chiral particle emission mechanism and its predictions of charmonium-like structures
Chen, Dian-Yong
http:///ir.lzu.edu.cn/:80/handle/262010/583820
2024-03-15T02:33:02Z
2024-03-15T02:33:02Z
题名: The initial single chiral particle emission mechanism and its predictions of charmonium-like structures
作者: Chen, Dian-Yong
摘要: We propose a new mechanism, named as the initial single chiral particle emission mechanism, to explain the charged Zb(10610) and Zb(10650) observed in the Υ(5S) → π+π-Υ(nS), π+π-hb(mP), (n = 1 ∼ 3, m = 1, 2) processes. After successfully interpreting the charge Zb structures, we extend this mechanism to study the process of the dipion transitions between the higher charmonia/charmonium-like state and the lower charmonia. In these transitions process, we predict two charmonium analogs of the charged Zb. After the observations of Zc(3900) by the BESIII and the Belle Collaborations, we reproduce the dipion and the J/ψπ invariant mass distributions simultaneously with the initial single chiral particle emission mechanism. In addition, we predict some enhancements in the J/ψK invariant mass spectra in the dikaon decay of the higher charmonium and the charmonium like states. © The Authors.
2024-03-15T02:33:02Z
Experimental studies on astrophysical reactions at the low-energy RI beam separator CRIB
Yamaguchi, H.
Hayakawa, S.
Ma, N.R.
Shimizu, H.
Okawa, K.
Yang, L.
Kahl, D.
La Cognata, M.
Lamia, L.
Abe, K.
Beliuskina, O.
Cha, S.M.
Chae, K.Y.
Cherubini, S.
Figuera, P.
Ge, Z.
Gulino, M.
Hu, J.
Inoue, A.
Iwasa, N.
Kim, A.
Kim, D.
Kiss, G.
Kubono, S.
La Commara, M.
Lattuada, M.
Lee, E.J.
Moon, J.Y.
Palmerini, S.
Parascandolo, C.
Park, S.Y.
Phong, V.H.
Pierroutsakou, D.
Pizzone, R.G.
Rapisarda, G.G.
Romano, S.
Spitaleri, C.
Tang, X.D.
Trippella, O.
Tumino, A.
Zhang, N.T.
Lam, Y.H.
Heger, A.
Jacobs, A.M.
Xu, S.W.
Ma, S.B.
Ru, L.H.
Liu, E.Q.
Liu, T.
Hamill, C.B.
Murphy, A.St.J.
Su, J.
Fang, X.
Kwag, M.S.
Duy, N.N.
Uyen, N.K.
Kim, D.H.
Liang, J.
Psaltis, A.
Sferrazza, M.
Johnston, Z.
Li, Y.Y.
http:///ir.lzu.edu.cn/:80/handle/262010/583819
2024-03-15T02:33:01Z
2024-03-15T02:33:00Z
题名: Experimental studies on astrophysical reactions at the low-energy RI beam separator CRIB
作者: Yamaguchi, H.; Hayakawa, S.; Ma, N.R.; Shimizu, H.; Okawa, K.; Yang, L.; Kahl, D.; La Cognata, M.; Lamia, L.; Abe, K.; Beliuskina, O.; Cha, S.M.; Chae, K.Y.; Cherubini, S.; Figuera, P.; Ge, Z.; Gulino, M.; Hu, J.; Inoue, A.; Iwasa, N.; Kim, A.; Kim, D.; Kiss, G.; Kubono, S.; La Commara, M.; Lattuada, M.; Lee, E.J.; Moon, J.Y.; Palmerini, S.; Parascandolo, C.; Park, S.Y.; Phong, V.H.; Pierroutsakou, D.; Pizzone, R.G.; Rapisarda, G.G.; Romano, S.; Spitaleri, C.; Tang, X.D.; Trippella, O.; Tumino, A.; Zhang, N.T.; Lam, Y.H.; Heger, A.; Jacobs, A.M.; Xu, S.W.; Ma, S.B.; Ru, L.H.; Liu, E.Q.; Liu, T.; Hamill, C.B.; Murphy, A.St.J.; Su, J.; Fang, X.; Kwag, M.S.; Duy, N.N.; Uyen, N.K.; Kim, D.H.; Liang, J.; Psaltis, A.; Sferrazza, M.; Johnston, Z.; Li, Y.Y.
摘要: Experimental studies on astrophysical reactions involving radioactive isotopes (RI) often accompany technical challenges. Studies on such nuclear reactions have been conducted at the low-energy RI beam separator CRIB, operated by Center for Nuclear Study, the University of Tokyo. We discuss two cases of astrophysical reaction studies at CRIB; one is for the 7Be+n reactions which may affect the primordial 7Li abundance in the Big-Bang nucleosynthesis, and the other is for the 22Mg(α, p) reaction relevant in X-ray bursts. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).
2024-03-15T02:33:00Z
Regulated NiCu Cycles with the New 57Cu(p,γ)58Zn Reaction Rate and the Influence on Type-I X-Ray Bursts: GS 1826−24 Clocked Burster
Lam, Yi Hua
Lu, Ning
Heger, Alexander
Jacobs, Adam Michael
Smirnova, Nadezda A.
Nieto, Teresa Kurtukian
Johnston, Zac
Kubono, Shigeru
http:///ir.lzu.edu.cn/:80/handle/262010/583818
2024-03-15T02:32:59Z
2024-03-15T02:32:59Z
题名: Regulated NiCu Cycles with the New 57Cu(p,γ)58Zn Reaction Rate and the Influence on Type-I X-Ray Bursts: GS 1826−24 Clocked Burster
作者: Lam, Yi Hua; Lu, Ning; Heger, Alexander; Jacobs, Adam Michael; Smirnova, Nadezda A.; Nieto, Teresa Kurtukian; Johnston, Zac; Kubono, Shigeru
摘要: In Type-I X-ray bursts (XRBs), the rapid-proton capture (rp-) process passes through the NiCu and ZnGa cycles before reaching the region above Ge and Se isotopes that hydrogen burning actively powers the XRBs. The sensitivity study performed by Cyburt et al. [1] shows that the 57Cu(p,γ)58Zn reaction in the NiCu cycles is the fifth most important rp-reaction influencing the burst light curves. Langer et al. [2] precisely measured some low-lying energy levels of 58Zn to deduce the 57Cu(p,γ)58Zn reaction rate. Nevertheless, the order of the 1+1 and 2+3 resonance states that dominate at 0.2 T(GK) 0.8 is not confirmed. The 1+2 resonance state, which dominates at the XRB sensitive temperature regime 0.8 T(GK) 2 was not detected. Using isobaric-multipletmass equation (IMME), we estimate the order of the 1+1 and 2+3 resonance states and estimate the lower limit of the 1+2 resonance energy. We then determine the 57Cu(p,γ)58Zn reaction rate using the full pf-model space shell model calculations. The new rate is up to a factor of four lower than the Forstner et al. [3] rate recommended by JINA REACLIBv2.2. Using the present 57Cu(p,γ)58Zn, the latest 56Ni(p,γ)57Cu and 55Ni(p,γ)56Cu reaction rates, and 1D implicit hydrodynamic Kepler code, we model the thermonuclear XRBs of the clocked burster GS 1826−24. We find that the new rates regulate the reaction flow in the NiCu cycles and strongly influence the burst-ash composition. The 59Cu(p,α)56Ni and 59Cu(p,γ)60Zn reactions suppress the influence of the 57Cu(p,γ)58Zn reaction. They strongly diminish the impact of the nuclear reaction flow that bypasses the 56Ni waiting point induced by the 55Ni(p,γ)56Cu reaction on burst light curve. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).
2024-03-15T02:32:59Z
Description of weak-interaction rates within the relativistic energy density functional theory
Ravlić, Ante
Yüksel, Esra
Niu, Yifei
Paar, Nils
Colò, Gianluca
Khan, Elias
http:///ir.lzu.edu.cn/:80/handle/262010/583817
2024-03-15T02:32:58Z
2024-03-15T02:32:58Z
题名: Description of weak-interaction rates within the relativistic energy density functional theory
作者: Ravlić, Ante; Yüksel, Esra; Niu, Yifei; Paar, Nils; Colò, Gianluca; Khan, Elias
摘要: A new theoretical framework has been established and applied in the calculation of electron capture (EC) and β-decay rates in stellar environment, characterized by high density and temperature. For the description of the nuclear properties, the finite-temperature Hartree Bardeen-Cooper-Schrieffer (FT-HBCS) theory based on the relativistic derivative-coupling D3C∗ interaction is employed. In order to describe the charge-exchange transitions, the finite-temperature proton-neutron quasi-particle random-phase approximation is developed (FT-PNRQRPA) which includes both temperature and pairing correlations. In the FT-HBCS calculations, only the isovector pairing is included, while in the residual interaction of the FT-PNRQRPA both the isovector and isoscalar pairing contribute. In this work, results for EC and β-decay rates are presented in the temperature interval T = 0-1.5 MeV and stellar density ρYe = 107 and 109 g/cm3. Both allowed 0+, 1+ and first-forbidden transitions 0−, 1− and 2− are included in the calculations. It is shown that interplay between pairing correlations and finite-temperature effects can lead to significant changes in rates. It is also important to include de-excitations, i.e. transitions with negative Qvalue, that become increasingly significant at higher temperatures especially for p f -shell nuclei. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).
2024-03-15T02:32:58Z
Simulation of the dynamical transmission of 100 eV positrons through a conical capillary
Yang, Aixiang
Zhou, Dianwei
Han, Chengzhi
Chen, Ximeng
Shao, Jianxiong
http:///ir.lzu.edu.cn/:80/handle/262010/583781
2024-03-15T02:27:54Z
2024-03-15T02:27:53Z
题名: Simulation of the dynamical transmission of 100 eV positrons through a conical capillary
作者: Yang, Aixiang; Zhou, Dianwei; Han, Chengzhi; Chen, Ximeng; Shao, Jianxiong
摘要: The simulation of 100 eV positrons transmitted in conical capillary was performed with inserted beam intensity from 0.04 fA/mm2 to 10 fA/mm2. At lower injected intensity of sub-fA, the transmission profile is geometrical and dominated by direct transmission. As the tilt angle increases, the intensity of the transmitted positron decreases rapidly, which is consistent with the experimental data. After increasing injected current intensities to several fA/mm2, charge deposited in the capillary significantly enhances the transmission rate, and the positrons can transmit the capillary with larger tilt angles. The transmitted current density is shown to increase up to a factor of 4.8 with respect to the injected one. These results provide evidence that the low-energy positrons can be guided and significantly focused by insulating conical capillary. © 2024 Elsevier B.V.
2024-03-15T02:27:53Z
An evaluation of Ar ion milling in TEM sample preparation by energy-filtered TEM technique
Meng, Xuan
Zhao, Jiangtao
http:///ir.lzu.edu.cn/:80/handle/262010/583775
2024-03-15T02:27:40Z
2024-03-15T02:27:39Z
题名: An evaluation of Ar ion milling in TEM sample preparation by energy-filtered TEM technique
作者: Meng, Xuan; Zhao, Jiangtao
摘要: Irradiated materials impose unique challenges when it comes to sample preparation for transmission electron microscopy (TEM) analysis. After the preparation of TEM samples by electrolytic polish, Ar ion milling was usually used to remove the surface contamination, as well as to thin the samples to desired thickness. Therefore, it is necessary to evaluate the advantages and limitations of Ar ion milling technique. In this work, the optimum milling condition with minimal surface artifacts was determined by Ar ion milling with various incident angles and beam energies, and the high-resolution TEM (HR-TEM) examinations confirmed the optimum condition to be 4.0keV Ar ions with incident angles of ±4°. In addition, Ar ion milling and subsequent thickness measurement by energy-filtered TEM (EF-TEM) were conducted to determine the thinning rate. It is found that electrolytic polished TEM lamella has a wedge-shape structure with a very sharp edge, and the thinning rates varied from 9.7±1.4nm/minute to 5.0±2.3nm/minute across the TEM lamella for 4.0keV Ar ions. However, the thinning rates for 2keV and 1keV Ar ions were under the examination limit, and they were supposed not sufficient to thin the tungsten samples. Even though the exact thinning rate varies for different materials, the general trends for the Ar ion milling observed in this study can be used as a guidance. © 2024 Elsevier Ltd
2024-03-15T02:27:39Z
Nuclear ground-state properties probed by the relativistic Hartree–Bogoliubov approach
Liu, Zi Xin
Lam, Yi Hua
Lu, Ning
Ring, Peter
http:///ir.lzu.edu.cn/:80/handle/262010/583752
2024-03-15T02:26:13Z
2024-03-15T02:26:13Z
题名: Nuclear ground-state properties probed by the relativistic Hartree–Bogoliubov approach
作者: Liu, Zi Xin; Lam, Yi Hua; Lu, Ning; Ring, Peter
摘要: Using the relativistic Hartree–Bogoliubov approach with separable pairing force coupled with the latest point-coupling and meson-exchange covariant density functionals, i.e., PC-L3R, PC-X, DD-MEX, and DD-PCX, we systematically explore the ground-state properties of all isotopic chains from oxygen (Z=8) to darmstadtium (Z=110). These properties consist of the binding energies (Eb), one- and two-neutron separation energies (Sn and S2n), root-mean-square radii of matter (Rm), of neutron (Rn), of proton (Rp) and of charge (Rc) distributions, Fermi surfaces (λ), ground-state spins (J) and parities (π). We then use these calculated properties to predict the edges of nuclear landscape and bound nuclei for the isotopic chains of Z = 8–110. The number of bound nuclei predicted by PC-L3R, PC-X, DD-MEX, and DD-PCX, are 9004, 9162, 7112, and 6799, respectively. These latest covariant density functionals produce a set of rather similar proton drip lines due to the strong repulsive Coulomb force shifting up the single-proton energy of the proton-rich nuclei. PC-L3R and PC-X estimate more extended borders of the neutron-rich region compared with the neutron drip lines estimated by DD-MEX, and DD-PCX. Meanwhile, the root-mean-square deviations of one- (two-) neutron separation energies yielded from PC-L3R, PCX, DD-MEX, and DD-PCX are 0.962 (1.300) MeV, 0.920 (1.483) MeV, 1.010 (1.544) MeV, and 0.993 (1.753) MeV, respectively. The deviations of theoretical Sn, S2n, and charge radii from the available experimental ones increase at the regions further away from the proton magic numbers, indicating the important role of deformation in these regions. The root-mean-square deviations of charge radius distributions of comparing the available experimental values with the theoretical counterparts resulted from PC-L3R, PC-X, DD-MEX, and DD-PCX are 0.035 fm, 0.037 fm, 0.034 fm, and 0.035 fm, respectively. We compute and present the root-mean-square radii of neutron distributions for all isotopes of 8≤Z≤110 with respect to the empirical Rn. Basically, the systematic trends of the theoretical root-mean-square radii of neutron distributions generated from PC-L3R and PC-X closely follow the empirical Rn, except for the region of extreme neutron-rich nuclei, whereas DD-PCX produces a trend lower than the empirical Rn at the Nn at nuclei near the neutron drip line of the Mg, Ca, and Kr isotopic chains, suggesting the possible existence of the halo or giant halo phenomena. © 2024 Elsevier Inc.
2024-03-15T02:26:13Z
Free-space competition between gain-swept superradiance and spontaneous emission from N2+ in a femtosecond filament
Zhang, Yuxuan
Gao, Yitan
Lei, Hongbin
Zhu, Zoumingyang
Hu, Bitao
Zhao, Kun
Zhao, Zengxiu
Ding, Pengji
Liu, Zuoye
http:///ir.lzu.edu.cn/:80/handle/262010/583746
2024-03-15T02:25:58Z
2024-03-15T02:25:57Z
题名: Free-space competition between gain-swept superradiance and spontaneous emission from N2+ in a femtosecond filament
作者: Zhang, Yuxuan; Gao, Yitan; Lei, Hongbin; Zhu, Zoumingyang; Hu, Bitao; Zhao, Kun; Zhao, Zengxiu; Ding, Pengji; Liu, Zuoye
摘要: Air lasing from the singly ionized nitrogen molecule N2+ in a femtosecond laser filament under low gas pressures has been of intense interest in the field of ultrafast optics in the past decade. Several theoretical models have been proposed to explain the origin of N2+ lasing, but none of them have considered the competition between spontaneous emission and gain-swept lasing from N2+ in the filamentation process. In this work, we experimentally investigate such competition by measuring the dynamic fluorescence distribution along the filament in the presence of an external probe pulse. The results show that the occurrence of lasing in the middle of the filament reduces the side fluorescence and the absorption of lasing in the rear part of the filament increases the fluorescence. By solving a time-dependent nonlinear Schrödinger equation and applying the transient ionization injection model, population distributions along the filament are numerically simulated and well explain our experimental observations. © 2024 American Physical Society.
2024-03-15T02:25:57Z