16 results on '"Bai, X. X."'
Search Results
2. Proton widths of the low-lying 16F states from the 15N(7Li, 6Li)16N reaction
- Author
-
Wu, Z. D., Guo, B., Li, Z. H., Li, Y. J., Su, J., Pang, D. Y., Yan, S. Q., Li, E. T., Bai, X. X., Du, X. C., Fan, Q. W., Gan, L., He, J. J., Jin, S. J., Jing, L., Li, L., Li, Z. C., Lian, G., Liu, J. C., Shen, Y. P., Wang, Y. B., Yu, X. Q., Zeng, S., Zhang, D. H., Zhang, L. Y., Zhang, W. J., and Liu, W. P.
- Subjects
Nuclear Experiment - Abstract
All the 16F levels are unbound by proton emission. To date the four low-lying 16F levels below 1 MeV have been experimentally identified with well established spin-parity values and excitation energies with an accuracy of 4 - 6 keV. However, there are still considerable discrepancies for their level widths. The present work aims to explore these level widths through an independent method. The angular distributions of the 15N(7Li, 6Li)16N reaction leading to the first four states in 16N were measured using a high-precision Q3D magnetic spectrograph. The neutron spectroscopic factors and the asymptotic normalization coefficients for these states in 16N were then derived based on distorted wave Born approximation analysis. The proton widths of the four low-lying resonant states in 16F were obtained according to charge symmetry of strong interaction., Comment: 14 pages, 6 figures, 4 tables
- Published
- 2014
- Full Text
- View/download PDF
3. Spectroscopic factors for low-lying 16N levels and the astrophysical 15N(n,gamma)16N reaction rate
- Author
-
Guo, B., Li, Z. H., Li, Y. J., Su, J., Pang, D. Y., Yan, S. Q., Wu, Z. D., Li, E. T., Bai, X. X., Du, X. C., Fan, Q. W., Gan, L., He, J. J., Jin, S. J., Jing, L., Li, L., Li, Z. C., Lian, G., Liu, J. C., Shen, Y. P., Wang, Y. B., Yu, X. Q., Zeng, S., Zhang, L. Y., Zhang, W. J., and Liu, W. P.
- Subjects
Nuclear Experiment - Abstract
Fluorine is a key element for nucleosynthetic studies since it is extremely sensitive to the physical conditions within stars. The astrophysical site to produce fluorine is suggested to be asymptotic giant branch (AGB) stars. In these stars the 15N(n, g)16N reaction could affect the abundance of fluorine by competing with 15N(a, g)19F. The 15N(n, g)16N reaction rate depends directly on the neutron spectroscopic factors of the low-lying states in 16N. The angular distributions of the 15N(7Li, 6Li)16N reaction populating the ground state and the first three excited states in 16N are measured using a Q3D magnetic spectrograph and are used to derive the spectroscopic factors of these states based on distorted wave Born approximation (DWBA) analysis. The spectroscopic factors of these four states are extracted to be 0.96+-0.09, 0.69+-0.09, 0.84+-0.08 and 0.65+-0.08, respectively. Based on the new spectroscopic factors we derive the 15N(n,g)16N reaction rate. The accuracy and precision of the spectroscopic factors are enhanced due to the first application of high-precision magnetic spectrograph for resolving the closely-spaced 16N levels which can not be achieved in most recent measurement. The present result demonstrates that two levels corresponding to neutron transfers to the 2s1/2 orbit in 16N are not so good single-particle levels although 15N is a closed neutron-shell nucleus. This finding is contrary to the shell model expectation. The present work also provides an independent examination to shed some light on the existing discrepancies in the spectroscopic factors and the 15N(n, g)16N rate., Comment: 13 pages, 4 figures, 2 tables
- Published
- 2013
- Full Text
- View/download PDF
4. Determination of astrophysical 12N(p,g)13O reaction rate from the 2H(12N, 13O)n reaction and its astrophysical implications
- Author
-
Guo, B., Su, J., Li, Zhihong, Wang, Y. B., Yan, S. Q., Li, Y. J., Shu, N. C., Han, Y. L., Bai, X. X., Chen, Y. S., Liu, W. P., Yamaguchi, H., Binh, D. N., Hashimoto, T., Hayakawa, S., Kahl, D., Kubono, S., He, J. J., Hu, J., Xu, S. W., Iwasa, N., Kume, N., and Li, Zhihuan
- Subjects
Nuclear Experiment - Abstract
The evolution of massive stars with very low-metallicities depends critically on the amount of CNO nuclides which they produce. The $^{12}$N($p$,\,$\gamma$)$^{13}$O reaction is an important branching point in the rap-processes, which are believed to be alternative paths to the slow 3$\alpha$ process for producing CNO seed nuclei and thus could change the fate of massive stars. In the present work, the angular distribution of the $^2$H($^{12}$N,\,$^{13}$O)$n$ proton transfer reaction at $E_{\mathrm{c.m.}}$ = 8.4 MeV has been measured for the first time. Based on the Johnson-Soper approach, the square of the asymptotic normalization coefficient (ANC) for the virtual decay of $^{13}$O$_\mathrm{g.s.}$ $\rightarrow$ $^{12}$N + $p$ was extracted to be 3.92 $\pm$ 1.47 fm$^{-1}$ from the measured angular distribution and utilized to compute the direct component in the $^{12}$N($p$,\,$\gamma$)$^{13}$O reaction. The direct astrophysical S-factor at zero energy was then found to be 0.39 $\pm$ 0.15 keV b. By considering the direct capture into the ground state of $^{13}$O, the resonant capture via the first excited state of $^{13}$O and their interference, we determined the total astrophysical S-factors and rates of the $^{12}$N($p$,\,$\gamma$)$^{13}$O reaction. The new rate is two orders of magnitude slower than that from the REACLIB compilation. Our reaction network calculations with the present rate imply that $^{12}$N($p,\,\gamma$)$^{13}$O will only compete successfully with the $\beta^+$ decay of $^{12}$N at higher ($\sim$two orders of magnitude) densities than initially predicted., Comment: 8 figures, 2 tables, Submitted to Physical Review C
- Published
- 2012
- Full Text
- View/download PDF
5. New determination of the 13C(a, n)16O reaction rate and its influence on the s-process nucleosynthesis in AGB stars
- Author
-
Guo, B., Li, Z. H., Lugaro, M., Buntain, J., Pang, D. Y., Li, Y. J., Su, J., Yan, S. Q., Bai, X. X., Chen, Y. S., Fan, Q. W., Jin, S. J., Karakas, A. I., Li, E. T., Li, Z. C., Lian, G., Liu, J. C., Liu, X., Shi, J. R., Shu, N. C., Wang, B. X., Wang, Y. B., Zeng, S., and Liu, W. P.
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Nuclear Experiment - Abstract
We present a new measurement of the $\alpha$-spectroscopic factor ($S_\alpha$) and the asymptotic normalization coefficient (ANC) for the 6.356 MeV 1/2$^+$ subthreshold state of $^{17}$O through the $^{13}$C($^{11}$B, $^{7}$Li)$^{17}$O transfer reaction and we determine the $\alpha$-width of this state. This is believed to have a strong effect on the rate of the $^{13}$C($\alpha$, $n$)$^{16}$O reaction, the main neutron source for {\it slow} neutron captures (the $s$-process) in asymptotic giant branch (AGB) stars. Based on the new width we derive the astrophysical S-factor and the stellar rate of the $^{13}$C($\alpha$, $n$)$^{16}$O reaction. At a temperature of 100 MK our rate is roughly two times larger than that by \citet{cau88} and two times smaller than that recommended by the NACRE compilation. We use the new rate and different rates available in the literature as input in simulations of AGB stars to study their influence on the abundances of selected $s$-process elements and isotopic ratios. There are no changes in the final results using the different rates for the $^{13}$C($\alpha$, $n$)$^{16}$O reaction when the $^{13}$C burns completely in radiative conditions. When the $^{13}$C burns in convective conditions, as in stars of initial mass lower than $\sim$2 $M_\sun$ and in post-AGB stars, some changes are to be expected, e.g., of up to 25% for Pb in our models. These variations will have to be carefully analyzed when more accurate stellar mixing models and more precise observational constraints are available.
- Published
- 2012
- Full Text
- View/download PDF
6. Asymptotic normalization coefficient from the 12C(7Li,6He)13N reaction and the astrophysical 12C(p,g)13N reaction rate
- Author
-
Li, Z. H., Su, J., Guo, B., Li, Z. C., Bai, X. X., Liu, J. C., Li, Y. J., Yan, S. Q., Wang, B. X., Wang, Y. B., Lian, G., Zeng, S., Li, E. T., Fang, X., Liu, W. P., Chen, Y. S., Shu, N. C., and Fan, Q. W.
- Subjects
Nuclear Experiment - Abstract
Angular distribution of the 12C(7Li,6He)13N reaction at E(7Li) = 44.0 MeV was measured at the HI-13 tandem accelerator of Beijing, China. Asymptotic normalization coefficient (ANC) of 13N = 12C + p was derived to be 1.64 $\pm$ 0.11 fm$^{-1/2}$ through distorted wave Born approximation (DWBA) analysis. The ANC was then used to deduce the astrophysical $S(E)$ factors and reaction rates for direct capture in 12C(p,g)13N at energies of astrophysical relevance., Comment: 13 pages, 4 figues, submitted to Nucl. Phys. A
- Published
- 2009
7. Optical potential parameters from 12C + Zr elastic scattering
- Author
-
Gan L., Li Z. H., Sun H. B., Su J., Li Y. J., Yan S. Q., Wang Y. B., Zeng S., Bai X. X., Du X. C., Wu Z. D., Jin S. J., Zhang W. J., Liu W. P., and Li E. T.
- Subjects
Physics ,QC1-999 - Abstract
The angular distributions of 12C + 90,92,94,96Zr elastic scattering were measured with the Q3D magnetic spectrometer at the HI-13 tandem accelerator, Beijing. The real part of optical potential were extracted by analysing these angular distributions. The analysis enable us to avoid the influence of Coulomb effect and to observe the dependence of optical potential on the nuclear properties. With the deduced potential parameters, the experimental elastic scattering angular distributions can be reproduced very well. Formulas to infer global heavy-ion potential parameters were obtained then by analyzing the extracted optical potential parameters. The formulas can be used widely in heavy-ion nuclear reactions.
- Published
- 2016
- Full Text
- View/download PDF
8. Spectroscopic factors for low-lying 16N levels and the astrophysical 15N(n,gamma)16N reaction rate
- Author
-
Guo, B., Li, Z. H., Li, Y. J., Su, J., Pang, D. Y., Yan, S. Q., Wu, Z. D., Li, E. T., Bai, X. X., Du, X. C., Fan, Q. W., Gan, L., He, J. J., Jin, S. J., Jing, L., Li, L., Li, Z. C., Lian, G., Liu, J. C., Shen, Y. P., Wang, Y. B., Yu, X. Q., Zeng, S., Zhang, L. Y., Zhang, W. J., and Liu, W. P.
- Subjects
FOS: Physical sciences ,Nuclear Experiment (nucl-ex) ,Nuclear Experiment - Abstract
Fluorine is a key element for nucleosynthetic studies since it is extremely sensitive to the physical conditions within stars. The astrophysical site to produce fluorine is suggested to be asymptotic giant branch (AGB) stars. In these stars the 15N(n, g)16N reaction could affect the abundance of fluorine by competing with 15N(a, g)19F. The 15N(n, g)16N reaction rate depends directly on the neutron spectroscopic factors of the low-lying states in 16N. The angular distributions of the 15N(7Li, 6Li)16N reaction populating the ground state and the first three excited states in 16N are measured using a Q3D magnetic spectrograph and are used to derive the spectroscopic factors of these states based on distorted wave Born approximation (DWBA) analysis. The spectroscopic factors of these four states are extracted to be 0.96+-0.09, 0.69+-0.09, 0.84+-0.08 and 0.65+-0.08, respectively. Based on the new spectroscopic factors we derive the 15N(n,g)16N reaction rate. The accuracy and precision of the spectroscopic factors are enhanced due to the first application of high-precision magnetic spectrograph for resolving the closely-spaced 16N levels which can not be achieved in most recent measurement. The present result demonstrates that two levels corresponding to neutron transfers to the 2s1/2 orbit in 16N are not so good single-particle levels although 15N is a closed neutron-shell nucleus. This finding is contrary to the shell model expectation. The present work also provides an independent examination to shed some light on the existing discrepancies in the spectroscopic factors and the 15N(n, g)16N rate., Comment: 13 pages, 4 figures, 2 tables
- Published
- 2014
- Full Text
- View/download PDF
9. Optical potential parameters from12C + Zr elastic scattering
- Author
-
Gan, L., primary, Li, Z. H., additional, Sun, H. B., additional, Su, J., additional, Li, Y. J., additional, Yan, S. Q., additional, Wang, Y. B., additional, Zeng, S., additional, Bai, X. X., additional, Du, X. C., additional, Wu, Z. D., additional, Jin, S. J., additional, Zhang, W. J., additional, Liu, W. P., additional, and Li, E. T., additional
- Published
- 2016
- Full Text
- View/download PDF
10. Two measurements of the 22Na+p resonant scattering via thicktarget inverse-kinematics method.
- Author
-
Wang, Y. B., Jin, S. J., Jing, L., Han, Z. Y., Bai, X. X., Guo, B., Li, Y. J., Li, Z. H., Lian, G., Su, J., Sun, L. J., Yan, S. Q., Zeng, S., Liu, W. P., Yamaguchi, H., Kubono, S., Hu, J., Kahl, D., He, J. J., and Wang, J. S.
- Subjects
ELASTIC scattering ,SODIUM ,KINEMATICS ,RADIOISOTOPES ,RADIOACTIVITY ,CHARGE exchange reactions ,EXCITATION energy (In situ microanalysis) - Abstract
22 Na is an important isotope for the study of extinct radioactivity, meanwhile its sufficiently long half life provides the possibility to observe live22 Na in nearby nova explosions. The22 Na(p,γ)23 Mg is one of the key reactions that influence the22 Na abundance in nova ejecta. To study the proton resonant states in23 Mg relevant to the astrophysical22 Na(p,γ)23 Mg reaction rates, two measurements have been carried out at the CRIB separator of University of Tokyo, and the RIBLL secondary beamline in Lanzhou, respectively. The22 Na secondary beam was produced via the ¹H(22 Ne,22 Na)n charge exchange reaction. Thick-target inverse-kinematics method is applied to obtain the excitation function of22 Na+p elastic scattering. Extended gas target and solid state polyethylene foil were used in the two measurements, respectively, to map the different excitation energy region of the compound nucleus23 Mg. Several new resonant levels are observed and their contribution to the22 Na(p,γ)23 Mg reaction rate is evaluated. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
11. Optical potential parameters from 12C + Zr elastic scattering.
- Author
-
Gan, L., Li, Z. H., Sun, H. B., Su, J., Li, Y. J., Yan, S. Q., Wang, Y. B., Zeng, S., Bai, X. X., Du, X. C., Wu, Z. D., Jin, S. J., Zhang, W. J., Liu, W. P., and Li, E. T.
- Subjects
ELASTIC scattering ,MAGNETIC spectrometer ,TANDEM accelerators ,ANGULAR distribution (Nuclear physics) ,HEAVY ion collisions - Abstract
The angular distributions of
12 C +90,92,94,96 zr elastic scattering were measured with the Q3D magnetic spectrometer at the HI-13 tandem accelerator, Beijing. The real part of optical potential were extracted by analysing these angular distributions. The analysis enable us to avoid the influence of Coulomb effect and to observe the dependence of optical potential on the nuclear properties. With the deduced potential parameters, the experimental elastic scattering angular distributions can be reproduced very well. Formulas to infer global heavy-ion potential parameters were obtained then by analyzing the extracted optical potential parameters. The formulas can be used widely in heavy-ion nuclear reactions. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
12. NEW DETERMINATION OF THE13C(α,n)16O REACTION RATE AND ITS INFLUENCE ON THEs-PROCESS NUCLEOSYNTHESIS IN AGB STARS
- Author
-
Guo, B., primary, Li, Z. H., additional, Lugaro, M., additional, Buntain, J., additional, Pang, D. Y., additional, Li, Y. J., additional, Su, J., additional, Yan, S. Q., additional, Bai, X. X., additional, Chen, Y. S., additional, Fan, Q. W., additional, Jin, S. J., additional, Karakas, A. I., additional, Li, E. T., additional, Li, Z. C., additional, Lian, G., additional, Liu, J. C., additional, Liu, X., additional, Shi, J. R., additional, Shu, N. C., additional, Wang, B. X., additional, Wang, Y. B., additional, Zeng, S., additional, and Liu, W. P., additional
- Published
- 2012
- Full Text
- View/download PDF
13. Current progress of nuclear astrophysical reaction and decay study at CIAE
- Author
-
Liu, W P, primary, Li, Z H, additional, Guo, B, additional, Wang, Y B, additional, Su, J, additional, Bai, X X, additional, Lian, G, additional, Wang, B X, additional, Yan, S Q, additional, Zeng, S, additional, Li, Y J, additional, Li, E T, additional, Jin, S J, additional, and Liu, X, additional
- Published
- 2011
- Full Text
- View/download PDF
14. Determination of astrophysical 11C(p, γ)12N reaction rate from the asymptotic normalization coefficients of 12B →11B + n
- Author
-
Guo, B, primary, Li, Z H, additional, Liu, W P, additional, and Bai, X X, additional
- Published
- 2006
- Full Text
- View/download PDF
15. Revalidation of the isobaric multiplet mass equation at A=53, T=3/2
- Author
-
Su, J., Zhang, N., T., Shen, Y., P., Lam, Y., H., Smirnova, N., A., Liu W., P., Zhang N., T., Shen Y., P., Lam Y., H., Smirnova N., A., MacCormick, M., Wang J., S., Jing, L., Li Z., H., Wang Y., B., Guo, B., Yan S., Q., Li Y., J., Zeng, S., Lian, G., Du X., C., Gan, L., Bai X., X., Gao Z., C., Zhang Y., H., Zhou X., H., Tang X., D., He J., J., Yang Y., Y., Jin S., L., Ma, P., Ma J., B., Huang M., R., Bai, Z., Zhou Y., J., Ma W., H., Hu, J., Xu S., W., Ma S., B., Chen S., Z., Zhang, Ling Yan, Ding, B., Audi, G., Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), CSNSM SNO, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
- Subjects
Nuclear and High Energy Physics ,Mass excess ,TI-41 ,Proton decay ,Isobaric multiplet mass equation ,LINE ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,01 natural sciences ,Nuclear physics ,0103 physical sciences ,BETA-DECAY ,010306 general physics ,Multiplet ,Line (formation) ,Physics ,[PHYS]Physics [physics] ,NUCLEI ,010308 nuclear & particles physics ,Isobaric analog state ,Beta decay ,lcsh:QC1-999 ,Mass formula ,MODEL ,Isobaric process ,Atomic physics ,lcsh:Physics ,Excitation ,HIGH-RESOLUTION ,COEFFICIENTS ,β-Delayed γ decay - Abstract
International audience; The T = 3/2 isobaric analog state (IAS) in Co-53 is firmly established through a comprehensive measurement of beta-delayed gamma and proton decay of Ni-53. The determined excitation energy of Co-53 IAS combined with the mass of Co-53 generates a precise mass excess of -38 333.6(27) keV for the Co-53 IAS, which is 70(18) keV lower than the previously adopted value. The new result solves a problem raised by incorrect assignments of the Co-53 IAS of unexpected deviation from the isobaric multiplet mass equation (IMME) at A = 53, T = 3/2. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.
- Full Text
- View/download PDF
16. Fluorine intake of a Tibetan population
- Author
-
Cao, J., Zhao, Y., Liu, J. W., Bai, X. X., Zhou, D. Y., Fang, S. L., Jia, M., and Wu, J. S.
- Published
- 1996
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.