WorldWideScience

Sample records for e1-transitions

  1. Evidence for the two-body nature of the E1 transition operator in the sdf-interacting boson model

    Energy Technology Data Exchange (ETDEWEB)

    Barfield, A.F.; Brentano, P. von; Dewald, A.; Zell, K.O.; Zamfir, N.V.; Bucurescu, D.; Ivascu, M.; Scholten, O.

    1989-01-01

    Two new a absolute transition rates are reported for the nucleus /sup 144/Sm following an (..cap alpha.., ..cap alpha..') Coulomb excitation study. They are B(E3;3/sup -/ -> 0/sup +/)=(38+-3)W.u. and B(E1;3/sup -/ -> 2/sup +/)=2.8+-0.4)x10/sup -3/W.u. This large E1 matrix element, along with the previously known B(E1;1/sup -/ -> 0/sup +/) value support the interpretation of the 1/sup -/ state in this nucleus as 2-phonon 2/sup +/x3/sup -/ excitation. In the frame of the IBM-1+f-boson model we show the need for a two-body term in the E1 transition operator. Estimates for the strenghts of the one and two-body parts of the E1 transition operator are obtained from these experimental data.

  2. Sensitive search for the temporal variation of the fine structure constant using radio-frequency E1 transitions in atomic dysprosium

    CERN Document Server

    Nguyen, A T; Lamoreaux, S K; Torgerson, J R

    2003-01-01

    It has been proposed that the radio-frequency electric-dipole (E1) transition between two nearly degenerate opposite-parity states in atomic dysprosium should be highly sensitive to possible temporal variation of the fine structure constant ($\\alpha$) [V. A. Dzuba, V. V. Flambaum, and J. K. Webb, Phys. Rev. A {\\bf 59}, 230 (1999)]. We discuss here an experimental realization of the proposed search, which involves monitoring the E1 transition frequency over a period of time using direct frequency counting techniques. We estimate that a statistical sensitivity of $|\\adota| \\sim 10^{-18}$/yr may be achieved and discuss possible systematic effects in such a measurement.

  3. Reinvestigation of the high spin states in ^(161)Er and enhanced E1 transitions in the N=93 isotones

    Institute of Scientific and Technical Information of China (English)

    陈亮; 周厚兵; 丁兵; 王海霞; 郑勇; 竺礼华; 吴晓光; 周小红; 张玉虎; 柳敏良; 王世陶; 方永得; 滑伟; 强赟华; 李广顺

    2011-01-01

    High-spin states in 161Er have been studied experimentally using the 150Nd(16O, 5n) reaction at a beam energy of 86 MeV. The relatively enhanced E1 transitions between the 5/2+[642] and 3/2-[521] bands are observed in 161Er, and the B(E1) values are extra

  4. Open charm contributions to the E1 transitions of ψ(3686) and ψ(3770) → γχ{sub cJ}

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Zheng [Chinese Academy of Sciences, Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Beijing (China); Cleven, Martin [Chinese Academy of Sciences, Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Beijing (China); Universitat de Barcelona, Departament de Fisica Quantica i Astrofisica, Barcelona (Spain); Wang, Qian [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Zhao, Qiang [Chinese Academy of Sciences, Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Beijing (China); Hunan Normal University, Synergetic Innovation Center for Quantum Effects and Applications (SICQEA), Changsha (China)

    2016-11-15

    The E1 transitions of ψ(3686) and ψ(3770) → γχ{sub cJ} are investigated in a non-relativistic effective field theory (NREFT) where the open charm effects are included systematically as the leading corrections. It also allows a self-consistent inclusion of the S-D mixing in the same framework. We are able to show that the open charm contributions are essential for understanding the rather unexpected discrepancies between the non-relativistic leading order calculations and the experimental data for these two low-lying states. (orig.)

  5. Phenomenology of heavy quarkonium radiative E1 transitions

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Hector E. [Physik-Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching (Germany)

    2016-01-22

    We present preliminary results of the evaluation of the next-to-leading-order (NLO) relativistic corrections to the heavy quarkonium electric dipole transition (E1) rate. In our evaluation we use the quark-antiquark potential up to 1/m{sup 2} corrections that includes the effective string theory expression for the long range, a review on the method to construct this potential is given. Our results compare favorable with the experiments and may provide predictions for the rates for which no experimental data is yet available.

  6. Multi-configuration Dirac-Hartree-Fock calculations of the transition rates of 2s22p2 - 2s2p3 and 2s2p3 - 2s22pnl (n ≥ 3) E1 transitions of N+

    Science.gov (United States)

    Shen, Xiaozhi; Liu, Juan; Zhou, Fuyang

    2016-10-01

    Wavefunctions were determined using the multi-configuration Dirac-Hartree-Fock method. The core-core, core-valence, valence correlation, Breit interaction and quantum electrodynamics effects, as well as some higher-order correlation effects, were considered to obtain accurate wavelengths (λ), oscillator strengths (gf) and transition rates (A) of 2s22p2 - 2s2p3, 2s2p3 - 2s22pnl (n ≥ 3) and 2s2p3 - 2s2p23s E1 transitions. The branching ratio of 2s2p3 5S^o_2 (namely Aλ2143.45/Aλ2139.68) based on the latest calculation of 2.462 ± 0.119 is recommended for the determination of a nebula's electron temperature and electron density. The largest calculated gf value of 2s2p3 - 2s22p4p is λ630.65, differing from that of λ1060.2 (i.e. 2s2p3 3P^o_2 - 2s22p4p 3S1) that was observed with the largest intensities in the Orion Nebula spectrum. In addition, the energy levels and the splittings of 2s2p3, the extremely difficult calculations of the rates of two-electron one-photon transitions as well as those of the very small intercombination A of 2s2p3 5S^o_2 were studied in detail. Because of the weak spin-orbit interaction, accurately calculating the levels 3P^o_{1,2,0} (or 3D^o_{3,2,1}) and their transition matrix elements is very sensitive to relativistic and electron correlation effects. A special case for this is when the transition operators synchronously applied to wavefunctions with regard to 2s2p3 3Po and 2s22pnl (n = 4) become extremely sensitive to some higher-order correlation effects.

  7. Evidence for the two-body nature of the E1 transition operator in the sdf-interacting boson model

    NARCIS (Netherlands)

    Barfield, A. F.; von Brentano, P.; Dewald, A.; Zell, K. O.; Zamfir, N. V.; Bucurescu, D.; Ivaşcu, M.; Scholten, O.

    1989-01-01

    Two new absolute transition rates are reported for the nucleus144Sm following an ( α, α') Coulomb excitation study. They are B(E3; 3-→ 0+)=(38±3) W.u. and B(E1;3- → 2+)=(2.8±0.4)×10-3 W.u. This large E1 matrix element, along with the previously known B(E1; 1- →+) value support the interpretation of

  8. E 1 transitions from the. Upsilon. prime prime state and the fine structure of the. chi. sub b prime states

    Energy Technology Data Exchange (ETDEWEB)

    Narain, M.; Lovelock, D.M.J.; Heintz, U.; Lee-Franzini, J.; Schamberger, R.D.; Willins, J.; Yanagisawa, C. (State University of New York at Stony Brook, Stony Brook, New York 11794 (USA)); Franzini, P.; Tuts, P.M.; Kanekal, S.; Wu, Q.W. (Columbia University, New York, New York 10027 (USA))

    1991-06-17

    Using the CUSB-II detector at the Cornell Electron Storage Ring, we have made precision measurements of the electric dipole transition rates from {Upsilon}{prime}{prime} to {chi}{sub {ital b}}{sup {prime}}, which are in excellent agreement with theory. The fine-structure splitting is found to be {ital M}({chi}{sub {ital b}2}{sup {prime}}){minus}{ital M}({chi}{sub {ital b}1}{sup {prime}})=13.5{plus minus}0.4{plus minus}0.5 MeV and {ital M}({chi}{sub {ital b}1}{sup {prime}}){minus}{ital M}({chi}{sub {ital b}0}{sup {prime}})=23.3{plus minus}0.7{plus minus}0.7 MeV, leading to a ratio {ital R}=0.584{plus minus}0.024{plus minus}0.02. The fine structure measures the relative contributions of the spin-orbit interaction {ital a}=9.5{plus minus}0.2{plus minus}0.1 MeV and tensor interaction {ital b}=2.3{plus minus}0.1{plus minus}0.1 MeV. We also find that the long-range confining potential transforms as a Lorentz scalar.

  9. Observation of chi(cJ) decays to Lambda(Lambda)over-bar pi(+)pi(-)

    NARCIS (Netherlands)

    Ablikim, M.; Achasov, M. N.; Ambrose, D. J.; An, F. F.; An, Q.; An, Z. H.; Bai, J. Z.; Ban, Y.; Becker, J.; Bennett, J. V.; Bertani, M.; Bian, J. M.; Boger, E.; Bondarenko, O.; Boyko, I.; Briere, R. A.; Bytev, V.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, S. J.; Chen, Y. B.; Cheng, H. P.; Chu, Y. P.; Cronin-Hennessy, D.; Dai, H. L.; Dai, J. P.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; Ding, W. M.; Ding, Y.; Dong, L. Y.; Dong, M. Y.; Du, S. X.; Fang, J.; Fang, S. S.; Fava, L.; Feldbauer, F.; Feng, C. Q.; Ferroli, R. B.; Fu, C. D.; Fu, J. L.; Gao, Y.; Geng, C.; Goetzen, K.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, Y. P.; Han, Y. L.; Harris, F. A.; He, K. L.; He, M.; He, Z. Y.; Held, T.; Heng, Y. K.; Hou, Z. L.; Hu, H. M.; Hu, J. F.; Hu, T.; Huang, G. M.; Huang, J. S.; Huang, X. T.; Huang, Y. P.; Hussain, T.; Ji, C. S.; Ji, Q.; Ji, X. B.; Ji, X. L.; Jiang, L. L.; Jiang, X. S.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jing, F. F.; Kalantar-Nayestanaki, N.; Kavatsyuk, M.; Kuehn, W.; Lai, W.; Lange, J. S.; Li, C. H.; Li, Cheng; Li, Cui; Li, D. M.; Li, F.; Li, G.; Li, H. B.; Li, J. C.; Li, K.; Li, Lei; Li, Q. J.; Li, S. L.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, X. R.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Liao, X. T.; Liu, B. J.; Liu, C. L.; Liu, C. X.; Liu, C. Y.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H.; Liu, H. B.; Liu, H. H.; Liu, H. M.; Liu, H. W.; Liu, J. P.; Liu, K. Y.; Liu, Kai; Liu, P. L.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, X. H.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqiang; Liu, Zhiqing; Loehner, H.; Lu, G. R.; Lu, H. J.; Lu, J. G.; Lu, Q. W.; Lu, X. R.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Lv, M.; Ma, C. L.; Ma, F. C.; Ma, H. L.; Ma, Q. M.; Ma, S.; Ma, T.; Ma, X. Y.; Ma, Y.; Maas, F. E.; Maggiora, M.; Malik, Q. A.; Mao, Y. J.; Mao, Z. P.; Messchendorp, J. G.; Min, J.; Min, T. J.; Mitchell, R. E.; Mo, X. H.; Morales, C. Morales; Motzko, C.; Muchnoi, N. Yu.; Muramatsu, H.; Nefedov, Y.; Nicholson, C.; Nikolaev, I. B.; Ning, Z.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Park, J. W.; Pelizaeus, M.; Peng, H. P.; Peters, K.; Ping, J. L.; Ping, R. G.; Poling, R.; Prencipe, E.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, X. S.; Qin, Y.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Rong, G.; Ruan, X. D.; Sarantsev, A.; Schaefer, B. D.; Schulze, J.; Shao, M.; Shen, C. P.; Shen, X. Y.; Sheng, H. Y.; Shepherd, M. R.; Song, X. Y.; Spataro, S.; Spruck, B.; Sun, D. H.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tapan, I.; Thorndike, E. H.; Toth, D.; Ullrich, M.; Varner, G. S.; Wang, B.; Wang, B. Q.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, Q.; Wang, Q. J.; Wang, S. G.; Wang, X. L.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. Y.; Wei, D. H.; Weidenkaff, P.; Wen, Q. G.; Wen, S. P.; Wiedner, U.; Wu, L. H.; Wu, N.; Wu, S. X.; Wu, W.; Wu, Z.; Xia, L. G.; Xiao, Z. J.; Xie, Y. G.; Xiu, Q. L.; Xu, G. F.; Xu, G. M.; Xu, H.; Xu, Q. J.; Xu, X. P.; Xu, Z. R.; Xue, F.; Xue, Z.; Yan, L.; Yan, W. B.; Yan, Y. H.; Yang, H. X.; Yang, Y.; Yang, Y. X.; Ye, H.; Ye, M.; Ye, M. H.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yu, S. P.; Yuan, C. Z.; Yuan, Y.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, S. H.; Zhang, X. J.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Y. S.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, H. S.; Zhao, J. W.; Zhao, K. X.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, X. H.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, Y. H.; Zhong, B.; Zhong, J.; Zhou, L.; Zhou, X. K.; Zhou, X. R.; Zhu, C.; Zhu, K.; Zhu, K. J.; Zhu, S. H.; Zhu, X. L.; Zhu, X. W.; Zhu, Y. C.; Zhu, Y. M.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.; Werner, M.J.; Zheng, J.P.

    2012-01-01

    Decays of the chi(cJ) states (J = 0, 1, 2) to Lambda(Lambda) over bar pi(+)pi(-), including processes with intermediate Sigma(1385), are studied through the E1 transition psi(1) -> gamma chi(cJ) using 106 x 10(6) psi(1) events collected with the BESIII detector at BEPCII. This is the first observati

  10. Investigation of Dilaton-Gluon Coupling Potential in Charmonium Family

    Institute of Scientific and Technical Information of China (English)

    PING Rong-Gang; CHEN Hong; PING Rong-Xiang

    2006-01-01

    The behaviour of dilaton-gluon coupling (DGC) potential is investigated by studying charmonium spectra,annihilation rates and E1 transition rates systematically.We find that in the non-relativistic quantum chromodynamics approximation,the charmonium properties can be described by the DGC potential.

  11. E1, M1, E2 transition energies and probabilities of W$^{54+}$ ions

    CERN Document Server

    Ding, Xiao-bin; Liu, Jia-xin; Koike, Fumihiro; Murakami, Izumi; Kato, Daiji; Sakaue, Hiroyuki A; Nakamura, Nobuyuki; Dong, Chen-zhong

    2016-01-01

    A comprehensive theoretical study of the E1, M1, E2 transitions of Ca-like tungsten ions is presented. Using multi-configuration Dirac-Fock (MCDF) method with a restricted active space treatment, the wavelengths and probabilities of the M1 and E2 transitions between the multiplets of the ground state configuration ([Ne]3s$^{2}$3p$^{6}$3d$^{2}$) and of the E1 transitions between [Ne]3s$^{2}$3p$^{5}$3d$^{3}$ and [Ne]3s$^{2}$3p$^{6}$3d$^{2}$ have been calculated. The results are in reasonable agreement with available experimental data. The present E1 and M1 calculations are compared with previous theoretical values. For E2 transitions, the importance of electron correlation from 3s and 3p orbitals is pointed out. Several strong E1 transitions are predicted, which have potential advantage for plasma diagnostics.

  12. Pygmy dipole resonance in 208Pb

    CERN Document Server

    Poltoratska, I; Tamii, A; Adachi, T; Bertulani, C A; Carter, J; Dozono, M; Fujita, H; Fujita, K; Fujita, Y; Hatanaka, K; Itoh, M; Kawabata, T; Kalmykov, Y; Krumbholz, A M; Litvinova, E; Matsubara, H; Nakanishi, K; Neveling, R; Okamura, H; Ong, H J; Özel-Tashenov, B; Ponomarev, V Yu; Richter, A; Rubio, B; Sakaguchi, H; Sakemi, Y; Sasamoto, Y; Shimbara, Y; Shimizu, Y; Smit, F D; Suzuki, T; Tameshige, Y; Wambach, J; Yosoi, M; Zenihiro, J

    2012-01-01

    Scattering of protons of several hundred MeV is a promising new spectroscopic tool for the study of electric dipole strength in nuclei. A case study of 208Pb shows that at very forward angles J^pi = 1- states are strongly populated via Coulomb excitation. A separation from nuclear excitation of other modes is achieved by a multipole decomposition analysis of the experimental cross sections based on theoretical angular distributions calculated within the quasiparticle-phonon model. The B(E1) transition strength distribution is extracted for excitation energies up to 9 MeV, i.e., in the region of the so-called pygmy dipole resonance (PDR). The Coulomb-nuclear interference shows sensitivity to the underlying structure of the E1 transitions, which allows for the first time an experimental extraction of the strength and energy centroid of the PDR.

  13. Properties of octupole-vibrational bands in the 160Dy nucleus

    Science.gov (United States)

    Usmanov, P. N.; Solnyshkin, A. A.; Vdovin, A. I.; Salikhbaev, U. S.

    2014-11-01

    The mixing of octupole-vibrational bands in the 160Dy nucleus is analyzed within a phenomenological model that involves Coriolis coupling. The energies of levels in the bands, the reduced probabilities for E1 transitions from the octupole-vibrational bands to the ground-state and γ bands, and the ratios of the reduced probabilities for these transitions to the neighboring levels of the ground-state band are calculated. Satisfactory agreement with available experimental data is reached.

  14. Relativistic Many-body Moller-Plesset Perturbation Theory Calculations of the Energy Levels and Transition Probabilities in Na- to P-like Xe Ions

    Energy Technology Data Exchange (ETDEWEB)

    Vilkas, M J; Ishikawa, Y; Trabert, E

    2007-03-27

    Relativistic multireference many-body perturbation theory calculations have been performed on Xe{sup 43+}-Xe{sup 39+} ions, resulting in energy levels, electric dipole transition probabilities, and level lifetimes. The second-order many-body perturbation theory calculation of energy levels included mass shifts, frequency-dependent Breit correction and Lamb shifts. The calculated transition energies and E1 transition rates are used to present synthetic spectra in the extreme ultraviolet range for some of the Xe ions.

  15. The Measurement of the 12C(n, γ)13C Reaction in the Pygmy Resonance Region

    Science.gov (United States)

    Zhengde, Huang; Lihua, Zhu; Long, Ho; Xiamin, Shi; Dazho, Ding

    1991-10-01

    The excitation function of 12(n, γ0)13C reaction has been measured in the pygmy resonance region. The present results are in agreement with the results of ref. 8 and DSD calculation of ref. 7. The angular distributions of 12C(n,γ0) reaction were fitted by Legendre polynomials. It is concluded that the E1 transitions dominate in the 12C(n,γ0)13C reaction.

  16. Radiative Neutron Capture on Carbon-14 in Effective Field Theory

    CERN Document Server

    Rupak, Gautam; Vaghani, Akshay

    2012-01-01

    The cross section for radiative capture of neutron on carbon-14 is calculated using the model-independent formalism of halo effective field theory. The dominant contribution from E1 transition is considered, and the cross section is expressed in terms of elastic scattering parameters of the effective range expansion. Contributions from both resonant and non-resonant interaction are calculated. Significant interference between these leads to a capture contribution that deviates from simple Breit-Wigner resonance form.

  17. Radiative transitions in mesons in a non relativistic quark model

    OpenAIRE

    Bonnaz, R.; Silvestre-Brac, B.; Gignoux, C.

    2001-01-01

    In the framework of the non relativistic quark model, an exhaustive study of radiative transitions in mesons is performed. The emphasis is put on several points. Some traditional approximations (long wave length limit, non relativistic phase space, dipole approximation for E1 transitions, gaussian wave functions) are analyzed in detail and their effects commented. A complete treatment using three different types of realistic quark-antiquark potential is made. The overall agreement with experi...

  18. Radiative transitions in mesons in a non relativistic quark model

    CERN Document Server

    Bonnaz, R; Gignoux, C

    2002-01-01

    In the framework of the non relativistic quark model, an exhaustive study of radiative transitions in mesons is performed. The emphasis is put on several points. Some traditional approximations (long wave length limit, non relativistic phase space, dipole approximation for E1 transitions, gaussian wave functions) are analyzed in detail and their effects commented. A complete treatment using three different types of realistic quark-antiquark potential is made. The overall agreement with experimental data is quite good, but some improvements are suggested.

  19. Inter-band coincidences in the superdeformed well of {sup 190}Hg from gammasphere

    Energy Technology Data Exchange (ETDEWEB)

    Crowell, B.; Carpenter, M.P.; Janssens, R.V.F. [and others

    1995-08-01

    Very few experimental observables are ordinarily accessible for superdeformed (SD) states in the A {approximately} 150 and A {approximately} 190 regions. The gamma-decay out of the superdeformed bands usually proceeds directly to the normally deformed states, through highly fragmented pathways, making it difficult to determine the spins, parities and excitation energies of the SD states. The in-band E2 transitions are so collective (2 x 10{sup 3} single-particle units in the A {approximately} 190 region) that it is typically impossible to detect any of the competing M1 and E1 transitions between states in the SD well.

  20. Nuclear structure of {sup 231}Ac

    Energy Technology Data Exchange (ETDEWEB)

    Boutami, R. [Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, E-28006 Madrid (Spain); Borge, M.J.G. [Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, E-28006 Madrid (Spain)], E-mail: borge@iem.cfmac.csic.es; Mach, H. [Department of Radiation Sciences, ISV, Uppsala University, SE-751 21 Uppsala (Sweden); Kurcewicz, W. [Department of Physics, University of Warsaw, Pl-00 681 Warsaw (Poland); Fraile, L.M. [Departamento Fisica Atomica, Molecular y Nuclear, Facultad CC. Fisicas, Universidad Complutense, E-28040 Madrid (Spain); ISOLDE, PH Department, CERN, CH-1211 Geneva 23 (Switzerland); Gulda, K. [Department of Physics, University of Warsaw, Pl-00 681 Warsaw (Poland); Aas, A.J. [Department of Chemistry, University of Oslo, PO Box 1033, Blindern, N-0315 Oslo (Norway); Garcia-Raffi, L.M. [Instituto de Fisica Corpuscular, CSIC - Universidad de Valencia, Apdo. 22805, E-46071 Valencia (Spain); Lovhoiden, G. [Department of Physics, University of Oslo, PO Box 1048, Blindern, N-0316 Oslo (Norway); Martinez, T.; Rubio, B.; Tain, J.L. [Instituto de Fisica Corpuscular, CSIC - Universidad de Valencia, Apdo. 22805, E-46071 Valencia (Spain); Tengblad, O. [Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, E-28006 Madrid (Spain); ISOLDE, PH Department, CERN, CH-1211 Geneva 23 (Switzerland)

    2008-10-15

    The low-energy structure of {sup 231}Ac has been investigated by means of {gamma} ray spectroscopy following the {beta}{sup -} decay of {sup 231}Ra. Multipolarities of 28 transitions have been established by measuring conversion electrons with a MINI-ORANGE electron spectrometer. The decay scheme of {sup 231}Ra {yields}{sup 231}Ac has been constructed for the first time. The Advanced Time Delayed {beta}{gamma}{gamma}(t) method has been used to measure the half-lives of five levels. The moderately fast B(E1) transition rates derived suggest that the octupole effects, albeit weak, are still present in this exotic nucleus.

  1. Identification of the predicted 5s-4f level crossing optical lines with applications to metrology and searches for the variation of fundamental constants.

    Science.gov (United States)

    Windberger, A; Crespo López-Urrutia, J R; Bekker, H; Oreshkina, N S; Berengut, J C; Bock, V; Borschevsky, A; Dzuba, V A; Eliav, E; Harman, Z; Kaldor, U; Kaul, S; Safronova, U I; Flambaum, V V; Keitel, C H; Schmidt, P O; Ullrich, J; Versolato, O O

    2015-04-17

    We measure optical spectra of Nd-like W, Re, Os, Ir, and Pt ions of particular interest for studies of a possibly varying fine-structure constant. Exploiting characteristic energy scalings we identify the strongest lines, confirm the predicted 5s-4f level crossing, and benchmark advanced calculations. We infer two possible values for optical M2/E3 and E1 transitions in Ir^{17+} that have the highest predicted sensitivity to a variation of the fine-structure constant among stable atomic systems. Furthermore, we determine the energies of proposed frequency standards in Hf^{12+} and W^{14+}.

  2. Description of Four-Body Breakup Reaction with the Method of Continuum-Discretized Coupled-Channels

    CERN Document Server

    Egami, Tomoaki; Ogata, Kazuyuki; Yahiro, Masanobu

    2008-01-01

    We present a method for smoothing discrete breakup $S$-matrix elements calculated by the method of continuum-discretized coupled-channels (CDCC). This smoothing method makes it possible to apply CDCC to four-body breakup reactions. The reliability of the smoothing method is confirmed for two cases, $^{58}$Ni($d$, $p n$) at 80 MeV and the $E1$ transition of $^6$He. We apply CDCC with the smoothing method to $^6$He breakup reaction at 22.5 MeV. Multi-step breakup processes are found to be important.

  3. Isospin mixing in the N=Z nucleus {sup 64}Ge

    Energy Technology Data Exchange (ETDEWEB)

    Farnea, E.; De Angelis, G.; Gadea, A.; Bizzeti, P.G.; Dewald, A.; Eberth, J.; Algora, A.; Axiotis, M.; Bazzacco, D.; Bizzeti-Sona, A.M.; Brandolini, F.; Colo, G.; Gelletly, W.; Kaci, M.A.; Kintz, N.; Klug, T.; Kroell, Th.; Lenzi, S.M.; Lunardi, S.; Marginean, N.; Martinez, T.; Menegazzo, R.; Napoli, D.R.; Nyberg, J.; Pavan, P.; Podolyak, Zs.; Petrache, C.M.; Quintana, B.; Rubio, B.; Spolaore, P.; Steinhardt, Th.; Tain, J.L.; Thelen, O.; Ur, C.A.; Venturelli, R.; Weiszflog, M

    2003-01-02

    The N=Z nucleus {sup 64}Ge has been investigated in two experiments using the EUROBALL III and EUROBALL IV spectrometers coupled to ancillary devices. Multipole mixing ratios, linear polarization and picosecond lifetimes for various transitions have been measured. The linear polarization results determine unambiguously the multipole character of the 5{sup -}{yields}4{sup +} 1665 keV transition, allowing to extract the electric dipole strength and to investigate for the first time the amount of isospin mixing implied by the presence of a forbidden E1 transition.

  4. New results on the superdeformed {sup 196}Pb nucleus: The decay of the excited bands to the yrast band

    Energy Technology Data Exchange (ETDEWEB)

    Bouneau, S.; Azaiez, F.; Duprat, J. [IPN, Orsay (France)] [and others

    1996-12-31

    The study of the superdeformed (SD) {sup 196}Pb nucleus has been revisited using the EUROGAM phase 2 spectrometer. In addition to the known yrast and two lowest excited SD bands, a third excited SD band has been seen. All of the three excited bands were found to decay to the yrast SD band through, presumably, E1 transitions, allowing relative spin and excitation energy assignments. Comparisons with calculations using the random-phase approximation suggest that all three excited bands can be interpreted as octupole vibrational structures.

  5. Octupole shapes in heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.

    1994-08-01

    Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets.

  6. Photoreflectance Spectroscopy for Study of Si/SiGe/Si Heterostructure

    Institute of Scientific and Technical Information of China (English)

    Liu Zhihong; Chen Changchun; Lin Huiwang; Xiong Xiaoyi; Dou Weizhi; Tsien Pei-Hsin

    2004-01-01

    UHVCVD-grown Si/Si1- xGex/Si heterostructure was investigated by Photoreflectance spectroscopy (PR). The principle of PR used in semiconductor film was thoroughly described. According to the E1 transition energy in the Si1- xGex alloy, the Ge content in SiGe film with constant composition can be accurately characterized. In this study, determine the composition uniformity of larger diameter SiGe epiwafer by PR mapping technique was determined. These results show PR is very promising for Si1- xGex epilayer characterization with constant Ge content and can provide film measurements for production-worthy line monitor.

  7. Partial radiative strength functions for dipole transitions in the sup 4 sup 9 sup , sup 5 sup 1 V nuclei

    CERN Document Server

    Fedorets, I D

    2002-01-01

    Radiative strength functions for dipole transitions from the compound-nuclei states to excited states of the sup 4 sup 9 V and sup 5 sup 1 V nuclei are determined from the resonance-averaged intensities of primary gamma-rays in the (p, gamma) reaction measured in the proton energy range of 1.5-3.5 MeV. The data so obtained are compared with predictions of various models. The best description for E1 transitions is achieved on the base of the model accounting for the dependence of the strength function on the gamma-ray energy, temperature, and nuclear shell structure

  8. Nuclear structure of $^{231}$Ac

    CERN Document Server

    Boutami, R; Mach, H; Kurcewicz, W; Fraile, L M; Gulda, K; Aas, A J; García-Raffi, L M; Løvhøiden, G; Martínez, T; Rubio, B; Taín, J L; Tengblad, O

    2008-01-01

    The low-energy structure of 231Ac has been investigated by means of gamma ray spectroscopy following the beta-decay of 231Ra. Multipolarities of 28 transitions have been established by measuring conversion electrons with a mini-orange electron spectrometer. The decay scheme of 231Ra --> 231Ac has been constructed for the first time. The Advanced Time Delayed beta-gamma-gamma(t) method has been used to measure the half-lives of five levels. The moderately fast B(E1) transition rates derived suggest that the octupole effects, albeit weak, are still present in this exotic nucleus.

  9. Internal and external radiative widths in the combined R-matrix and potential model formalism

    CERN Document Server

    Mukhamedzhanov, A M; Bertulani, C A; Hao, T V Nhan

    2016-01-01

    Using the $R$-matrix approach we calculate the radiative width for a resonance decaying to a bound state through electric dipole, $E1$, transitions. The total radiative width is determined by the interference of the nuclear internal and external radiative width amplitudes. For a given channel radius the external radiative width amplitude is model independent and is determined by the asymptotic normalization coefficient (ANC) of the bound state to which the resonance decays. It also depends on the partial resonance width. To calculate the internal radiative width amplitude we show that a single particle potential model is appropriate. We compare our results with a few experimental data.

  10. The radiative proton capture on 16O at satrophysical energies

    CERN Document Server

    Dubovichenko, Sergey

    2016-01-01

    The possibility of description of the experimental data for the astrophysical S-factor of the proton radiative capture on 16O to the ground state of 17F was considered in the frame of the modified potential cluster model with forbidden states and classification of the states according to Young tableaux. It was shown that on the basis of the E1 transitions from the states of p16O scattering to the ground state of 17F in the p16O channel generally succeed to explain the value of measured cross sections at astrophysical energies.

  11. Parity-violating electric-dipole transitions in helium induced by the electron-electron neutral weak interaction

    Energy Technology Data Exchange (ETDEWEB)

    Esteve, J.G.; Morales, A.; Morales, J.; Nuez-Lagos, R.; Pacheco, A.F.

    1984-04-01

    The parity-violating E1 transitions between the n = 2 levels of atomic helium, induced by the electron-electron neutral weak interaction have been computed by using Coulomb-type wave functions and (up to 84 parameter) Hylleraas wave functions. The parity-violating matrix elements turn out to be of the same order of magnitude as those due to the electron-nucleus weak interaction, thus allowing one to conclude that the relative importance of both effects is to be traced to their corresponding effective coupling constants.

  12. The electric quadrupole moment of molecular hydrogen ions and their potential for a molecular ion clock

    CERN Document Server

    Bakalov, Dimitar

    2013-01-01

    The systematic shifts of the transition frequencies in the molecular hydrogen ions are of relevance to ultra-high-resolution radio-frequency, microwave and optical spectroscopy of these systems, performed in ion traps. We develop the ab-initio description of the interaction of the electric quadrupole moment of this class of molecules with the static electric field gradients present in ion traps. In good approximation, it is described in terms of an effective perturbation hamiltonian. An approximate treatment is then performed in the Born-Oppenheimer approximation. We give an expression of the electric quadrupole coupling parameter valid for all hydrogen molecular ion species and evaluate it for a large number of states of H2+, HD+, and D2+. The systematic shifts can be evaluated as simple expectation values of the perturbation hamiltonian. Results on radio-frequency (M1), one-photon electric dipole (E1) and two-photon E1 transitions between hyperfine states in HD+ are reported. For two-photon E1 transitions b...

  13. Theoretical study of the $\\alpha+d$ $\\rightarrow$ $^6$Li + $\\gamma $ astrophysical capture process in a three-body model

    CERN Document Server

    Tursunov, E M; Turakulov, S A; Bray, I

    2016-01-01

    The astrophysical capture process $\\alpha+d$ $\\rightarrow$ $^6$Li + $\\gamma$ is studied in a three-body model. The initial state is factorized into the deuteron bound state and the $\\alpha+d$ scattering state. The final nucleus $^6$Li(1+) is described as a three-body bound state $\\alpha+n+p$ in the hyperspherical Lagrange-mesh method. The contribution of the E1 transition operator from the initial isosinglet states to the isotriplet components of the final state is estimated to be negligible. An estimation of the forbidden E1 transition to the isosinglet components of the final state is comparable with the corresponding results of the two-body model. However, the contribution of the E2 transition operator is found to be much smaller than the corresponding estimations of the two-body model. The three-body model perfectly matches the new experimental data of the LUNA collaboration with the help of the spectroscopic factor 2.586, very consistent with the three-body structure of the final state.

  14. Theoretical study of the α +d →6Li +γ astrophysical capture process in a three-body model

    Science.gov (United States)

    Tursunov, E. M.; Kadyrov, A. S.; Turakulov, S. A.; Bray, I.

    2016-07-01

    The astrophysical capture process α +d →6Li is studied in a three-body model. The initial state is factorized into the deuteron bound state and the (α +d )-scattering state. The final nucleus 6Li (1+) is described as a three-body bound state α +n +p in the hyperspherical Lagrange-mesh method. The contribution of the E 1 -transition operator from the initial isosinglet states to the isotriplet components of the final state is estimated to be negligible. An estimation of the forbidden E 1 transition to the isosinglet components of the final state is comparable with the corresponding results of the two-body model. However, the contribution of the E 2 -transition operator is found to be much smaller than the corresponding estimations of the two-body model. The three-body model perfectly matches the new experimental data of the LUNA Collaboration with the spectroscopic factor of 2.586 estimated from the bound-state wave functions of 6Li and a deuteron.

  15. Study of the thermal neutron radiative capture sup 31 P( n ,. gamma. ) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Zeng Xiantang; Shi Zongren; Zhang Ming; Li Guohua; Ding Dazhao (Institute of Atomic Energy, P. O. Box 275, Beijing (CN))

    1989-05-01

    The measurement of the {gamma}-ray spectrum of the {sup 31}P({ital n},{gamma}) reaction induced by thermal neutrons from the heavy water reactor is performed by using three crystal pair spectrometer'', Ge(Li) and HPGe detectors. 128 {gamma}-rays are identified, 24 of them are recognized as primary {gamma}-transitions. The excitation energies of 32 levels are deduced. Two possible levels of 5451.44 keV and 5021.10 keV have not been reported previously. The neutron separation energy is determined to be 7936.65(8) keV and partial cross sections are measured. The thermal neutron capture cross section of {sup 31}P is obtained to be 177(5) mb by comparison with Au({ital n}{sub th}, {gamma}) cross section standard. With the formula of the Lane-Lynn direct interaction, the partial capture cross sections of eight strong primary E1-transitions are calculated and compared with their experimental values, leading to the conclusion that the theoretical values are in coincidence with the experimental ones and the E1-transitions mainly come from 1+ capture state. The correlation analyses of the reduced strengths of E1 and M1 transitions with the spectroscopic factors of (d, p) reaction are performed and the reaction mechanisms discussed.

  16. Electromagnetic selection rules in the triangular α-cluster model of 12C

    Science.gov (United States)

    Stellin, G.; Fortunato, L.; Vitturi, A.

    2016-08-01

    After recapitulating the procedure to find the bands and the states occurring in the {{ D }}3h alpha-cluster model of 12C in which the clusters are placed at the vertexes of an equilateral triangle, we obtain the selection rules for electromagnetic transitions. While the alpha-cluster structure leads to the cancellation of E1 transitions, the approximations carried out in deriving the rotational-vibrational Hamiltonian lead to the disappearance of M1 transitions. Furthermore, although in general the lowest active modes are E2, E3, ... and M2, M3, ..., the cancellation of M2, M3 and M5 transitions between certain bands also occur as a result of the application of group theoretical techniques drawn from molecular physics. These implications can be very relevant for the spectroscopic analysis of γ-ray spectra of 12C.

  17. Examining the interplay between halo effects and deformation in neutron rich neon isotopes

    Science.gov (United States)

    Loelius, Charles; Iwasaki, Hironori; Bazin, Daniel; Elder, Robert; Elman, Brandon; Gade, Alexandra; Grinder, Mara; Longfellow, Brenden; Lunderberg, Eric; Heil, Sebastian; Hufnagel, Alexander; Mathy, Michael; Syndikus, Ina; Kobayashi, Nobu; Belarge, Joe; Bender, Peter; Weisshaar, Dirk; Petri, Marina; Whitmore, Kenneth

    2017-01-01

    27 Ne serves as an excellent test case for understanding the interplay between halo effects and deformation. It is known that the neighboring isotopes 26Ne and 28Ne demonstrate substantial deformation, which indicate a potential for deformation in 27Ne. At the same time, the 1/2+ excited state is expected to have a single valence neutron in the s orbital near the neutron separation energy and therefore is expected to exhibit halo effects. Due to the interplay between the halo and deformation effects, the M1 transition strength, which is expected to be large because of the deformation, could be severely reduced, while the E1 transition strength is expected to be large. To examine this effect, precise knowledge of transition rates is required. In this work, the model-independent Recoil Distance Method was employed with fast RI beams to constrain the lifetime of the 1/2+ state down to the lowest achievable limits of precision.

  18. Can Ab Initio Theory Explain the Phenomenon of Parity Inversion in 11Be?

    Science.gov (United States)

    Calci, Angelo; Navrátil, Petr; Roth, Robert; Dohet-Eraly, Jérémy; Quaglioni, Sofia; Hupin, Guillaume

    2016-12-01

    The weakly bound exotic 11Be nucleus, famous for its ground-state parity inversion and distinct n + 10Be halo structure, is investigated from first principles using chiral two- and three-nucleon forces. An explicit treatment of continuum effects is found to be indispensable. We study the sensitivity of the 11Be spectrum to the details of the three-nucleon force and demonstrate that only certain chiral interactions are capable of reproducing the parity inversion. With such interactions, the extremely large E 1 transition between the bound states is reproduced. We compare our photodisintegration calculations to conflicting experimental data and predict a distinct dip around the 3 /21- resonance energy. Finally, we predict low-lying 3 /2+ and 9 /2+ resonances that are not or not sufficiently measured in experiments.

  19. Can ab initio theory explain the phenomenon of parity inversion in ${}^{11}$Be?

    CERN Document Server

    Calci, Angelo; Roth, Robert; Dohet-Eraly, Jérémy; Quaglioni, Sofia; Hupin, Guillaume

    2016-01-01

    The weakly-bound exotic ${}^{11}$Be nucleus, famous for its ground-state parity inversion and distinct n+${}^{10}$Be halo structure, is investigated from first principles using chiral two- and three-nucleon forces. An explicit treatment of continuum effects is found to be indispensable. We study the sensitivity of the ${}^{11}$Be spectrum to the details of the three-nucleon force and demonstrate that only certain chiral interactions are capable of reproducing the parity inversion. With such interactions, the extremely large E1 transition between the bound states is reproduced. Our photo-disintegration calculations discriminate between conflicting experimental data and predict a distinct dip around the $3/2^-_1$ resonance energy. Finally, we predict low-lying $3/2^+$ and $9/2^+$ resonances that are not or not sufficiently measured in experiment.

  20. Octupole correlations in N =88 154Dy : Octupole vibration versus stable deformation

    Science.gov (United States)

    Zimba, G. L.; Sharpey-Schafer, J. F.; Jones, P.; Bvumbi, S. P.; Masiteng, L. P.; Majola, S. N. T.; Dinoko, T. S.; Lawrie, E. A.; Lawrie, J. J.; Negi, D.; Papka, P.; Roux, D.; Shirinda, O.; Easton, J. E.; Khumalo, N. A.

    2016-11-01

    We report on low-spin states of 154Dy populated via the reaction 155Gd (3He,4 n ) with a beam energy of 37.5 MeV from the Separated Sector Cyclotron at iThemba Laboratory. The AFRODITE γ-ray spectrometer was used to establish new E 1 transitions between bands of opposite parity. The measurements broaden the N =88 systematics on the relationship between the first excited positive-parity pairing isomer band and the lowest-lying negative-parity band as the nuclear quadrupole deformation decreases with increasing proton number. In a region of strong octupole correlations the data suggest that the spectroscopy of N =88 nuclei is driven by stable octupole deformations and not by vibrations.

  1. Electric and Magnetic Dipole States in ^238U

    Science.gov (United States)

    Hammond, S. L.; Adekola, A.; Angell, C. T.; Karwowski, H. J.; Howell, C. R.; Kwan, E.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Kelley, J. H.

    2010-11-01

    An investigation of dipole states in ^238U is important for the fundamental understanding of its structure. Precise experimental information on the distribution of M1 and E1 transitions in ^238U has been obtained using the nuclear resonance fluorescence technique at the High-Intensity γ-ray Source at the Triangle Universities Nuclear Laboratory. Using 100% linearly-polarized, monoenergetic γ-ray beams between incident energies of 2.0 - 5.5 MeV, the spin, parity, width, and γ-strength of the ground-state deexcitations were determined. These measurements will form a unique data set that can be used for comparison with theoretical models of collective excitations in heavy, deformed nuclei. The data can also provide isotope-specific signatures to search for special nuclear materials.

  2. Electromagnetic selection rules in the triangular alpha-cluster model of 12C

    CERN Document Server

    Stellin, G; Vitturi, A

    2015-01-01

    After recapitulating the procedure to find the bands and the states occurring in the $\\mathcal{D}_{3h}$ alpha-cluster model of $^{12}$C in which the clusters are placed at the vertexes of an equilateral triangle, we obtain the selection rules for electromagnetic transitions. While the alpha cluster structure leads to the cancellation of E1 transitions, the approximations carried out in deriving the roto-vibrational hamiltonian lead to the disappearance of M1 transitions. Furthermore, although in general the lowest active modes are E2, E3, $\\cdots$ and M2, M3, $\\cdots$, the cancellation of M2, M3 and M5 transitions between certain bands also occurs, as a result of the application of group theoretical techniques drawn from molecular physics. These implications can be very relevant for the spectroscopic analysis of $\\gamma$-ray spectra of $^{12}$C.

  3. Study of thermal neutron capture in /sup 32/S

    Energy Technology Data Exchange (ETDEWEB)

    GUO Taichang; SHI Zongren; ZENG Xiantang; LI Guohua; DING Dazhao

    1985-10-01

    The ..gamma..-ray spectrum of the /sup 32/S (n, ..gamma..) reaction at thermal neutron energy is measured by using a Ge(Li) detector. Among 86 ..gamma.. rays identified, 23 are recognized as primary ..gamma.. transitions. The excitation energies of 25 levels and the decay branching ratios are deduced. Three possible levels at 7505.0, 4473.1, and 2884.6 keV were not reported previously. The neutron separation energy of S is determined to be 8641.7 +- 0.6 keV. The thermal neutron capture cross section of /sup 32/S is determined to be 529 +- 26 mb by summing the transition intensities to the ground state of /sup 33/S and comparing with the well-known Au (n, ..gamma..) cross section. The partial capture cross sections of seven primary E1 transitions are calculated by the formula of the Lane-Lynn direct capture theory, and compared with measured values.

  4. Microscopic structure of deformed and superdeformed collective bands in rotating nuclei

    Science.gov (United States)

    Kvasil, J.; Iudice, N. Lo; Andreozzi, F.; Knapp, F.; Porrino, A.

    2007-03-01

    We investigate in self-consistent cranked Nilsson plus quasiparticle random-phase approximation the structure of Hg190,192,194 in their evolution from normal to superdeformation and from low to high rotational frequencies. The analysis of the energy levels suggests a splitting of few normally deformed bands into two or more branches. The investigation of the dynamical moments of inertia supports the octupole character of the low-lying negative parity superdeformed bands, in agreement with previous theoretical predictions and experimental findings. As a more direct confirm of their octupole nature, we obtain strong E1 transitions linking those bands to the yrast superdeformed band, in agreement with experiments. A similar result is shown to hold also for Dy152. Like in Dy152, the collectivity of the low-lying scissors mode gets enhanced with the onset of superdeformation.

  5. Evidence for the Direct Two-Photon Transition from $\\psi'$ to $J/\\psi$

    CERN Document Server

    Ablikim, M; Ambrose, D J; An, F F; An, Q; An, Z H; Bai, J Z; Ferroli, R B; Ban, Y; Becker, J; Berger, N; Bertani, M B; Bian, J M; Boger, E; Bondarenko, O; Boyko, I; Briere, R A; Bytev, V; Cai, X; Calcaterra, A C; Cao, G F; Chang, J F; Chelkov, G; Chen, G; Chen, H S; Chen, J C; Chen, M L; Chen, S J; Chen, Y; Chen, Y B; Cheng, H P; Chu, Y P; Cronin-Hennessy, D; Dai, H L; Dai, J P; Dedovich, D; Deng, Z Y; Denig, A; Denysenko, I; Destefanis, M; Ding, W M; Ding, Y; Dong, L Y; Dong, M Y; Du, S X; Fang, J; Fang, S S; Fava, L; Feldbauer, F; Feng, C Q; Fu, C D; Fu, J L; Gao, Y; Geng, C; Goetzen, K; Gong, W X; Gradl, W; Greco, M; Gu, M H; Gu, Y T; Guan, Y H; Guo, A Q; Guo, L B; Guo, Y P; Han, Y L; Hao, X Q; Harris, F A; He, K L; He, M; He, Z Y; Held, T; Heng, Y K; Hou, Z L; Hu, H M; Hu, J F; Hu, T; Huang, B; Huang, G M; Huang, J S; Huang, X T; Huang, Y P; Hussain, T; Ji, C S; Ji, Q; Ji, X B; Ji, X L; Jia, L K; Jiang, L L; Jiang, X S; Jiao, J B; Jiao, Z; Jin, D P; Jin, S; Jing, F F; Kalantar-Nayestanaki, N; Kavatsyuk, M; Kuehn, W; Lai, W; Lange, J S; Leung, J K C; Li, C H; Li, Cheng; Li, Cui; Li, D M; Li, F; Li, G; Li, H B; Li, J C; Li, K; Li, Lei; Li, N B; Li, Q J; Li, S L; Li, W D; Li, W G; Li, X L; Li, X N; Li, X Q; Li, X R; Li, Z B; Liang, H; Liang, Y F; Liang, Y T; Liao, G R; Liao, X T; Liu, B J; Liu, B J; Liu, C L; Liu, C X; Liu, C Y; Liu, F H; Liu, Fang; Liu, Feng; Liu, H; Liu, H B; Liu, H H; Liu, H M; Liu, H W; Liu, J P; Liu, Kun; Liu, Kai; Liu, K Y; Liu, P L; Liu, S B; Liu, X; Liu, X H; Liu, Y B; Liu, Y; Liu, Z A; Liu, Zhiqiang; Liu, Zhiqing; Loehner, H; Lu, G R; Lu, H J; Lu, J G; Lu, Q W; Lu, X R; Lu, Y P; Luo, C L; Luo, M X; Luo, T; Luo, X L; Lv, M; Ma, C L; Ma, F C; Ma, H L; Ma, Q M; Ma, S; Ma, T; Ma, X Y; Ma, Y; Maas, F E; Maggiora, M; Malik, Q A; Mao, H; Mao, Y J; Mao, Z P; Messchendorp, J G; Min, J; Min, T J; Mitchell, R E; Mo, X H; Morales, C Morales; Motzko, C; Muchnoi, N Yu; Nefedov, Y; Nicholson, C; Nikolaev, I B; Ning, Z; Olsen, S L; Ouyang, Q; Pacetti, S P; Park, J W; Pelizaeus, M; Peters, K; Ping, J L; Ping, R G; Poling, R; Prencipe, E; Pun, C S J; Qi, M; Qian, S; Qiao, C F; Qin, X S; Qin, Y; Qin, Z H; Qiu, J F; Rashid, K H; Rong, G; Ruan, X D; Sarantsev, A; Schulze, J; Shao, M; Shen, C P; Shen, X Y; Sheng, H Y; Shepherd, M R; Song, X Y; Spataro, S; Spruck, B; Sun, D H; Sun, G X; Sun, J F; Sun, S S; Sun, X D; Sun, Y J; Sun, Y Z; Sun, Z J; Sun, Z T; Tang, C J; Tang, X; Thorndike, E H; Tian, H L; Toth, D; Ulrich, M U; Varner, G S; Wang, B; Wang, B Q; Wang, K; Wang, L L; Wang, L S; Wang, M; Wang, P; Wang, P L; Wang, Q; Wang, Q J; Wang, S G; Wang, X F; Wang, X L; Wang, Y D; Wang, Y F; Wang, Y Q; Wang, Z; Wang, Z G; Wang, Z Y; Wei, D H; Weidenkaff, P; Wen, Q G; Wen, S P; Werner, M W; Wiedner, U; Wu, L H; Wu, N; Wu, S X; Wu, W; Wu, Z; Xia, L G; Xiao, Z J; Xie, Y G; Xiu, Q L; Xu, G F; Xu, G M; Xu, H; Xu, Q J; Xu, X P; Xu, Y; Xu, Z R; Xue, F; Xue, Z; Yan, L; Yan, W B; Yan, Y H; Yang, H X; Yang, T; Yang, Y; Yang, Y X; Ye, H; Ye, M; Ye, M H; Yu, B X; Yu, C X; Yu, J S; Yu, S P; Yuan, C Z; Yuan, W L; Yuan, Y; Zafar, A A; Zallo, A Z; Zeng, Y; Zhang, B X; Zhang, B Y; Zhang, C C; Zhang, D H; Zhang, H H; Zhang, H Y; Zhang, J; Zhang, J G; Zhang, J Q; Zhang, J W; Zhang, J Y; Zhang, J Z; Zhang, L; Zhang, S H; Zhang, T R; Zhang, X J; Zhang, X Y; Zhang, Y; Zhang, Y H; Zhang, Y S; Zhang, Z P; Zhang, Z Y; Zhao, G; Zhao, H S; Zhao, J W; Zhao, K X; Zhao, Lei; Zhao, Ling; Zhao, M G; Zhao, Q; Zhao, S J; Zhao, T C; Zhao, X H; Zhao, Y B; Zhao, Z G; Zhemchugov, A; Zheng, B; Zheng, J P; Zheng, Y H; Zheng, Z P; Zhong, B; Zhong, J; Zhou, L; Zhou, X K; Zhou, X R; Zhu, C; Zhu, K; Zhu, K J; Zhu, S H; Zhu, X L; Zhu, X W; Zhu, Y M; Zhu, Y S; Zhu, Z A; Zhuang, J; Zou, B S; Zou, J H; Zuo, J X

    2012-01-01

    The two-photon transition $\\psi' \\to \\gamma\\gamma J/\\psi$ is studied in a sample of 106 million $\\psi'$ decays collected by the BESIII detector. The branching fraction is measured to be $(3.3\\pm0.6(\\unit{stat})^{+0.8}_{-1.1}(\\unit{syst})) \\times10^{-4}$ using $J/\\psi \\to e^+e^-$ and $J/\\psi \\to \\mu^+\\mu^-$decays. This work represents the first measurement of a two-photon transition among charmonium states. The orientation of the $\\psi'$ decay plane and the $J/\\psi$ polarization in this decay are also studied. In addition, the product branching fractions of sequential $E1$ transitions $\\psi'\\to\\gamma\\chi_{cJ}$, $\\chi_{cJ}\\to\\gamma J/\\psi (J=0,1,2)$ are reported.

  6. The electric quadrupole moment of molecular hydrogen ions and their potential for a molecular ion clock

    Science.gov (United States)

    Bakalov, D.; Schiller, S.

    2014-01-01

    The systematic shifts of the transition frequencies in the molecular hydrogen ions are of relevance to ultra-high-resolution radio-frequency, microwave and optical spectroscopy of these systems, performed in ion traps. We develop the ab initio description of the interaction of the electric quadrupole moment of this class of molecules with the static electric field gradients present in ion traps. In good approximation, it is described in terms of an effective perturbation Hamiltonian. An approximate treatment is then performed in the Born-Oppenheimer approximation. We give an expression of the electric quadrupole coupling parameter valid for all hydrogen molecular ion species and evaluate it for a large number of states of H{2/+}, HD+, and D{2/+}. The systematic shifts can be evaluated as simple expectation values of the perturbation Hamiltonian. Results on radio-frequency, one-photon electric dipole (E1), and two-photon E1 transitions between hyperfine states in HD+ are reported. For two-photon E1 transitions between rotationless states, the shifts vanish. For a large subset of rovibrational one-photon transitions, the absolute values of the quadrupole shifts range from 0.3 to 10 Hz for an electric field gradient of 108 V/m2. We point out an experimental procedure for determining the quadrupole shift which will allow reducing its contribution to the uncertainty of unperturbed rovibrational transition frequencies to the 1 × 10-15 fractional level and, for selected transitions, even below it. The combined contributions of black-body radiation, Zeeman, Stark and quadrupole effects are considered for a large set of transitions, and it is estimated that the total transition frequency uncertainty of selected transitions can be reduced below the 1 × 10-15 level.

  7. Calculation of parity violating effects in the 6/sup 2/P/sub 1/2/-7/sup 2/P/sub 1/2/ forbidden M1 transition in thallium. [E1 amplitude, circular dichroism, parity violation, hyperfine structure

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, D.B.

    1977-05-01

    Calculations are presented of the E1 amplitude expected in forbidden M1 transitions of Tl and Cs if parity is violated in the neutral weak e-N interaction, as proposed in a number of gauge models, including that of Weinberg and Salam. Valence electron wave functions are generated as numerical solutions to the Dirac equation in a modified Tietz central potential. These wave functions are used to calculate allowed E1 transition rates, hfs splittings, and Stark E1 transition ampitudes. These results are compared with experiment and the agreement is generally good. The relativistic Tl 6/sup 2/P/sub 1/2/-7/sup 2/P/sub 1/2/ M1 transition amplitude M is also calculated, and corrections due to interconfiguration interaction, Breit interaction, and hfs mixing are included. The parity violating E1 amplitude E/sub PV/ is calculated and a value for the circular dichroism in the Weinberg model delta = -2.6 x 10/sup -3/ is obtained. Parity violating effects in other Tl transitions are discussed. Contributions to the M1 amplitude for the forbidden Cs 6/sup 2/S/sub 1/2/-7/sup 2/S/sub 1/2/ and 6/sup 2/S/sub 1/2/-8/sup 2/S/sub 1/2/ transitions and to the Cs 6/sup 2/S/sub 1/2/ g-factor anomaly from relativistic effects, Breit interaction, interconfiguration interaction, and hfs mixing are calculated, and it is found that this current theoretical description is not entirely adequate. The parity violating E1 amplitude E/sub PV/ for the 6S/sub 1/2/-7/sup 2/S/sub 1/2/ and 6S/sub 1/2/-8/sup 2/S/sub 1/2/ transitions is evaluated. With a measured value M/sub expt/ and the Weinberg value Q/sub W/ = -99, a circular dichroism delta = 1.64 x 10/sup -4/ for the 6/sup 2/S/sub 1/2/-7/sup 2/S/sub 1/2/ transition is found.

  8. 激光金等离子体中Au50+离子E1、M1跃迁的理论研究%E1 and M1 transitions of Au50+ in Au laser plasma

    Institute of Scientific and Technical Information of China (English)

    徐敏; 闫安英; 蒋刚

    2015-01-01

    根据全相对论组态相互作用(RCI)方法和多组态Dirac-Fock (MCDF)方法,考虑量子电动力学(QED)效应和Breit修正,选取重要的电子组态,系统计算了激光金等离子体中类铜Au50+离子nl−n′l′(n=4,l=s, p, d, f;n′=4,5,l′=s, p, d, f)电偶极(E1)跃迁和磁偶极(M1)跃迁的跃迁波长、跃迁几率和振子强度,并得到Au50+离子部分激发态能级结构。计算得到的能级与波长与其他已有的理论和实验结果进行了比较,得到了较为满意的结果。分别采用长度规范和速度规范对电偶极(E1)跃迁参数进行了计算和比较,得到了很好的收敛。计算结果还表明,对于高 Z高离化态离子,某些禁戒跃迁占有重要地位。%Using the fully relativistic configuration interaction (RCI) method and the multi-configuration Dirac-Fock (MCDF) method and taking quantum electrodynamical (QED) effect and Breit correction into account, wavelengths, transition probabilities and oscillator strengths were calculated for electric dipole (E1) transitions and magnetic dipole (M1) transitions in Au50+ ion. The obtained energy levels of some excited states and wavelengths of transitions in Au50+ ion from the method were compared with other theoretical and experimental results, and a good agreement with other results was shown. The calculated transition probabilities and oscillator strengths in E1 transitions using the velocity and length gauges respectively confirmed the accuracy of our calculations. The calculation results indicated that for high-Z highly ionized atom, some forbidden transitions could be very important.

  9. Atomic tests of symmetry principles

    Energy Technology Data Exchange (ETDEWEB)

    Davies, I.O.G.

    1986-01-01

    Parity non-conserving effects in atoms due to the neutral weak current interaction can be enhanced in two ways: by exploiting the Z-dependence and by using a near degeneracy between opposite parity states. In this thesis a case where both enhancements are simultaneously present is considered: samarium has Z = 62 and the states 4f{sup 6}6s6p {sup 7}G{sub 1}{sup 0} and 4f{sup 6}6d5d {sup 7}F{sub 1} are only 320 GHz apart. A calculation by Gongora and Sandars (1986) yields a value for R = Im {sup PNC}/ of 10{sup {minus}4}. To assess the feasibility of utilizing this gain to detect PNC effects a number of exploratory experiments have been performed and a new type of optical rotation experiment, involving crossed electric and magnetic fields,has been considered. Results are presented for the E1 transition 4f{sup 6}6s{sup 2} {sup 7}F{sub 0} - 4f{sup 6}6s6p {sup 7}G{sub 1} at 639 nm which include analyses of the absorption spectrum (both Doppler-broadened and Doppler-free), the Faraday and the Stark induced rotation. The data include measurements of isotope shifts and hyperfine structure constants, the oscillator strength (from the deduced natural linewidth) and the broadening constant for the He-Sm system. The Stark rotation was analyzed giving {vert bar}4f{sup 6}6s5d {sup 7}F{sub 1}{parallel}er{parallel}4f{sup 6}6s6p {sup 7}G{sub 1}{vert bar} = 0.85 (5) e a{sub 0}. The M1 resonance was located by Stark mixing and the background Faraday rotation in this region investigated. It is concluded that because of observed background, the low E1 transition amplitude measured and the low work function of samarium making the application of high electrical fields in the oven difficult that a PNC optical rotation experiment is unlikely to offer any advantage over existing experiments.

  10. Atomic Tests of Symmetry Principles.

    Science.gov (United States)

    Davies, I. O. G.

    Available from UMI in association with The British Library. Requires signed TDF. Parity non-conserving effects in atoms due to the neutral weak current interaction can be enhanced in two ways: by exploiting the Z-dependence and by using a near degeneracy between opposite parity states. In this thesis a case where both enhancements are simultaneously present is considered: samarium has Z = 62 and the states 4f^66s6p ^7G_sp{1} {0} and 4f^66d5d ^7F_1 are only 320 GHz apart. A calculation by Gongora and Sandars (1986) yields a value for R = Im ^{rm PNC}/ of 10^{-4}. To assess the feasibility of utilizing this gain to detect PNC effects a number of exploratory experiments have been performed and a new type of optical rotation experiment, involving crossed electric and magnetic fields, has been considered. Results are presented for the E1 transition 4f^6 6s^2 ^7F _0 - 4f^66s6p ^7G_1 at 639 nm which include analyses of the absorption spectrum (both Doppler-broadened and Doppler-free), the Faraday and the Stark induced rotation. The data include measurements of isotope shifts and hyperfine structure constants, the oscillator strength (from the deduced natural linewidth) and the broadening constant for the He-Sm system. Zeeman and optical coherences were discovered to be important in the analysis of the rotation spectra and a theoretical treatment involving density matrix equations is presented. In addition, for the odd isotopes, effects of optical pumping have also been considered. The Stark rotation was analysed giving |(4f^66s5d ^7F_1|er |4f^66s6p ^7G_1| = 0cdot85(5) e a_0 . The M1 resonance was located by Stark mixing and the background Faraday rotation in this region investigated. It is concluded that because of observed background, the low E1 transition amplitude measured and the low work function of samarium making the application of high electrical fields in the oven difficult that a PNC optical rotation experiment is unlikely to offer any advantage over existing

  11. Evidence for octupole vibration in the superdeformed well of {sup 190}Hg from eurogam

    Energy Technology Data Exchange (ETDEWEB)

    Crowell, B.; Carpenter, M.P.; Janssens, R.V.F. [and others

    1995-08-01

    Gammasphere experiments in 1993-94 brought to light the existence of an excited superdeformed (SD) band in {sup 190}Hg with the unusual property of decaying entirely to the lowest (yrast) SD band over 3-4 transitions, rather than to the normally deformed states as is usually the case in the A {approximately} 150 and A {approximately} 190 regions of superdeformation. Although M1 transitions between signature-partner SD bands were previously observed in {sup 193}Hg, no such mechanism was available to explain the situation in the even-even nucleus {sup 190}Hg, whose yrast SD band has no signature partner. The best explanation appears to lie in long-standing theoretical predictions that the SD minimum in the potential energy surface would be quite soft with respect to octupole vibrations. This would lead to enhanced E1 transitions connecting the one-phonon and zero-phonon states. The data and this interpretation were published. A shortcoming of the Gammasphere experiments was that they did not allow the definitive measurement of the energies of the gamma-ray transitions connecting the two bands, due to the very weak population of the excited band ({approximately}0.05% of the {sup 190}Hg channel) and also partly, we believed, to the angular distributions of the transitions, which were peaked near 90 degrees, where Gammasphere had few detectors.

  12. Ab initio description of continuum effects in A=11 exotic systems with chiral NN+3N forces

    Science.gov (United States)

    Calci, Angelo; Navratil, Petr; Roth, Robert; Dohet-Eraly, Jeremy; Quaglioni, Sofia; Hupin, Guillaume

    2016-09-01

    Based on the fundamental symmetries of QCD, chiral effective field theory (EFT) provides two- (NN), three- (3N) and many-nucleon interactions in a consistent and systematically improvable scheme. The rapid developments to construct divers families of chiral NN+3N interactions and the conceptual and technical improvements of ab initio many-body approaches pose a great opportunity for nuclear physics. By studying particular interesting phenomena in nuclear structure and reaction observables one can discriminate between different forces and study the predictive power of chiral EFT. The accurate description of the 11Be nucleus, in particular, the ground-state parity inversion and exceptionally strong E1 transition between its two bound states constitute an enormous challenge for the developments of nuclear forces and many-body approaches. We present a sensitivity analysis of structure and reaction observables to different NN+3N interactions in 11Be and n+10Be as well as the mirror p+10C scattering using the ab initio NCSM with continuum (NCSMC). Supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Work Proposal No. SCW1158. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada.

  13. Continuous reversal of Hanle resonances of counter-propagating pulse and continuous-wave field

    CERN Document Server

    Dimitrijević, Jelena; Jelenković, Branislav M

    2013-01-01

    In this work we study propagation dynamics of the two counter-propagating lasers, the continuous-wave (CW) laser and the pulse of another laser, when both lasers are tuned to the $F_{g}=2 \\rightarrow F_{e}=1$ transition in $^{87}$Rb, and therefore can develop Hanle electromagnetically induced transparency (EIT) in Rb vapor. We calculate transmission of both lasers as a function of applied magnetic field, and investigate how the propagation of the pulse affects the transmission of the CW laser. And vice versa, we have found conditions when the Gaussian pulse can either pass unchanged, or be significantly absorbed in the vacuum Rb cell. This configuration is therefore suitable for the convenient control of the pulse propagation and the system is of interest for optically switching of the laser pulses. In terms of the corresponding shapes of the coherent Hanle resonances, this is equivalent to turning the coherent resonance from Hanle EIT into electromagnetically induced absorption (EIA) peak. There is the range...

  14. Levels of 232U fed in 236Pu α decay

    Science.gov (United States)

    Ardisson, G.; Hussonnois, M.; Ledu, J. F.; Trubert, D.; Lederer, C. M.

    1994-06-01

    The γ spectrum following the α decay of 236Pu has been reinvestigated with a high-resolution HPGe detector. Accurate energies and intensities are reported for 26 γ transitions, of which 20 were observed for the first time. A decay scheme is constructed using the Ritz combination principle, γγ coincidence data, and previously known data from nuclear reactions and from232Pa β- decay. We observe feeding of the ground-state rotational band up to spin 8, the β vibrational band to spin 4, the K=0 octupole vibrational band to spin 5, and the bandhead of the γ vibrational band. New states of 232U at 927.3 and 967.7 keV, populated with low α-decay hindrance factors, are assigned as members of a second-excited Kπ=0+ band. The ratio of E1/E2 transitions in the decay of these states suggests that the E1 transitions to members of the K=0 octupole band may be rather fast (~=10-3 Weisskopf units). Systematics of hindrance factors for α decay to vibrational states are presented.

  15. Dispersion amplitudes in the Moessbauer lineshape of /sup 237/Np, /sup 182/W, and /sup 195/Pt

    Energy Technology Data Exchange (ETDEWEB)

    Potzel, W. (Technische Universitaet Muenchen, Garching, Ger.); Wagner, F.E.; Kalvius, G.M.; Asch, L.; Spirlet, J.C.; Mueller, W.

    1977-01-01

    Measurements of the dispersion amplitude for the Moessbauer resonances in /sup 237/Np (60 keV), /sup 182/W (100 keV) and /sup 195/Pt (99 keV) are reported. For the E1 transition in /sup 237/Np a value of xi = -(3.4 + 0.2) x 10/sup -2/ was found. Theoretical estimates of xi for this case are of limited accuracy and the comparison with experimental data is inaccurate because of the considerable line broadening. Computer simulations show the influence of xi on /sup 237/Np hyperfine spectra. For the E2 transition in /sup 182/W the dependence of the effective value of xi on absorber thickness was studied. Extrapolations to zero thickness yield xi = -(1.0 +- 0.1) x 10/sup -2/ in good agreement with theoretical calculations. For /sup 195/Pt we found xi = -(1.1 +- 0.3) x 10/sup -2/ for the dispersion amplitude at zero absorber thickness. This is the first pure M1 transition for which a dispersion term has been observed. For all three resonances the dispersion is large enough to affect the determination of isomer shifts.

  16. Direct Evidence of Octupole Deformation in Neutron-Rich $^{144}$Ba

    CERN Document Server

    Bucher, B; Wu, C Y; Janssens, R V F; Cline, D; Hayes, A B; Albers, M; Ayangeakaa, A D; Butler, P A; Campbell, C M; Carpenter, M P; Chiara, C J; Clark, J A; Crawford, H L; Cromaz, M; David, H M; Dickerson, C; Gregor, E T; Harker, J; Hoffman, C R; Kay, B P; Kondev, F G; Korichi, A; Lauritsen, T; Macchiavelli, A O; Pardo, R C; Richard, A; Riley, M A; Savard, G; Scheck, M; Seweryniak, D; Smith, M K; Vondrasek, R; Wiens, A

    2016-01-01

    The neutron-rich nucleus $^{144}$Ba ($t_{1/2}$=11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers $A$ less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced $E1$ transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multi-step Coulomb excitation of a post-accelerated 650-MeV $^{144}$Ba beam on a 1.0-mg/cm$^2$ $^{208}$Pb target. The measured value of the matrix element, $\\langle 3_1^- \\| \\mathcal{M}(E3) \\| 0_1^+ \\rangle=0.65(^{+17}_{-23})$ $e$b$^{3/2}$, corresponds to a reduced $B(E3)$ transition probability of 48($^{+25}_{-34}$) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.

  17. The Search For The Cp-violating Emission Of An E1 Photon From The Kaon Long Decays To Positive Pion Negative Pion Gamma

    CERN Document Server

    Shields, J M

    2005-01-01

    A search for the CP-violating electric dipole (E1) direct emission contribution to the KL → π+π −γ decay is performed using data from the 1997 KTeV/E832 experiment. Because the KL → π +π−γ decay mode is massively dominated by the CP-violating inner bremsstrahlung (IB) and the CP-conserving magnetic dipole (M1) direct emission processes, previous analyses have neglected the E1 contribution. Therefore, this measurement is the first attempt to directly quantify the size of the E1 decay process. This E1 transition is one of the very few CP-violating processes that is accessible to experiment and, in principle, will produce new insights into the structure of the neutral kaon. The result of this analysis is that the E1 contribution is below the threshold of sensitivity, and therefore an upper bound of |g E1| < 0.14 (90% CL) is reported. In the process of obtaining this upper limit, high resolution measurements of fit parame...

  18. Odd tensor E3 transitions and the generalized seniority in Sn-isotopes

    CERN Document Server

    Maheshwari, Bhoomika

    2016-01-01

    In our recent paper [Phys. Lett. B 753, (2016) 122], we have shown that both the odd and even tensor electric transition probabilities exhibit similar behavior within the generalized seniority scheme in a multi-j environment. This microscopic approach was used to show for the first time the occurrence of seniority isomers in the $ {13}^-$ isomers of Sn-isotopes, which decay by odd tensor $E1$ transition to the same seniority ($\\Delta v = 0$) state. In this letter, we extend our studies to odd tensor $E3$ transitions connecting different seniority states ($\\Delta v = 2$), and show for the first time that the generalized seniority scheme explains reasonably well the systematics of the $B(E3)$ values for the $(0^+ \\rightarrow 3_1^-)$ transitions in the Sn-isotopes. Additionally, we support these results by seniority guided Large Scale Shell Model (LSSM) calculations. The generalized seniority results are able to single out the most crucial valence space required in the LSSM calculations.

  19. Energy levels, radiative rates and electron impact excitation rates for transitions in Si III

    CERN Document Server

    Aggarwal, K M

    2016-01-01

    Energy levels and radiative rates (A-values) for four types of transitions (E1, E2, M1, and M2) are reported for an astrophysically important Mg-like ion Si~III, whose emission lines have been observed in a variety of plasmas. For the calculations, well-known and widely-used GRASP code has been adopted, and results are listed for transitions among the 141 levels of the 3$\\ell3\\ell'$ and 3$\\ell$4$\\ell$ configurations. Experimental energies are available for only the lowest 58 levels but there is no major discrepancy with theoretical results. Similarly, the A-values and lifetimes show a satisfactory agreement with other available results, particularly for strong E1 transitions. Collision strengths are also calculated, with the DARC code, and listed for resonance transitions over a wide energy range, up to 30~Ryd. No similar results are available in the literature for comparisons. However, comparisons are made with the more important parameter, effective collision strength ($\\Upsilon$), for which recent $R$-matr...

  20. VizieR Online Data Catalog: Iron Project. LIII. Fe XVII (Nahar+, 2003)

    Science.gov (United States)

    Nahar, S. N.; Eissner, W.; Chen, G. X.; Pradhan, A. K.

    2009-08-01

    An extensive set of fine structure levels and corresponding transition probabilities for allowed and forbidden transitions in Fe XVII is presented. A total of 490 bound energy levels of Fe XVII of total angular momenta 0parities with 2translate to over 2.6x104 allowed (E1) transitions that are of dipole and intercombination type, and 2312 forbidden transitions that include electric quadrupole (E2), magnetic dipole (M1), electric octopole (E3), and magnetic quadrupole (M2) type representing the most detailed calculations to date for the ion. Oscillator strengths f, line strengths S, and coefficients A of spontaneous emission for the E1 type transitions are obtained in the relativistic Breit-Pauli R-matrix approximation. A-values for the forbidden transitions are obtained from atomic structure calculations using codes SUPERSTRUCTURE and GRASP. The energy levels are identified in spectroscopic notation with the help of a newly developed level identification algorithm. Nearly all 52 spectroscopically observed levels have been identified, their binding energies agreeing within 1% with our calculation. Computed transition probabilities are compared with other calculations and measurement. The effect of 2-body magnetic terms and other interactions is discussed. The present data set enhances by more than an order of magnitude the heretofore available data for transition probabilities of Fe XVII. (11 data files).

  1. Atomic data from the Iron Project. LIII. Relativistic allowed and forbidden transition probabilities for Fe XVII

    CERN Document Server

    Nahar, S N; Chen, G X; Pradhan, A K; Nahar, Sultana N.; Eissner, Werner; Chen, Guo-Xin; Pradhan, Anil K.

    2003-01-01

    An extensive set of fine structure levels and corresponding transition probabilities for allowed and forbidden transitions in Fe XVII is presented. A total of 490 bound energy levels of Fe XVII of total angular momenta 0 <= J <= 7 of even and odd parities with 2 <= n <= 10, 0 <= l <= 8, 0 <= L <= 8, and singlet and triplet multiplicities, are obtained. They translate to over 2.6 x 10^4 allowed (E1) transitions that are of dipole and intercombination type, and about 3000 forbidden transitions that include electric quadrupole (E2), magnetic dipole (M1), electric octopole (E3), and magnetic quadrupole (M2) type representing the most detailed calculations to date for the ion. Oscillator strengths f, line strengths S, and coefficients A of spontaneous emission for the E1 type transitions are obtained in the relativistic Breit-Pauli R-matrix approximation. A valus for the forbidden transitions are obtained from atomic structure calculations using codes SUPERSTRUCTURE and GRASP. The energy le...

  2. Coexistence of symmetric and asymmetric shapes in $^{145}$/Ba, $^{145}$/La

    CERN Document Server

    Hamilton, J H; Jones, E F; Ramayya, A V; Hwang, J K; Gore, P M; Wang, M G; Cole, J D; Collins, W E; Peker, L K

    2000-01-01

    A new region of stable octupole deformation was predicted to occur with its center around the reinforcing shell gaps for beta /sub 3 /~0.15 at Z=56, N=88, and with /sub 56//sup 145/Ba/sub 89/ was predicted to be a prime candidate for stable octupole deformation. Evidence for stable octupole deformation was found in /sup 144/Ba, /sup 146/Ce and expanded to include odd-A /sup 143/Ba and other neighboring isotopes but was not observed in /sup 145/Ba. Recently we found evidence for the rotational enhancement of stable octupole deformation in /sup 145,147/La. In a reinvestigation of /sup 145/Ba, two new bands were discovered that are connected by enhanced, intertwined E1 transitions to two different previously known bands in /sup 145/Ba. These new data support the predicted presence of octupole deformation in /sup 145/Ba, which is rotation-enhanced above about spin 19/2. In both /sup 145/La and /sup 145/Ba, the low spin ground bands are built on a symmetric rotor shape and at intermediate spins there are shifts to...

  3. Multi-Configuration Dirac–Hartree–Fock (MCDHF Calculations for B-Like Ions

    Directory of Open Access Journals (Sweden)

    Indu Khatri

    2016-05-01

    Full Text Available Relativistic configuration interaction results are presented for several B-like ions (Ge XXVIII, Rb XXXIII, Sr XXXIV, Ru XL, Sn XLVI, and Ba LII using the multi-configuration Dirac–Hartree–Fock (MCDHF method. The calculations are carried out in the active space approximation with the inclusion of the Breit interaction, the finite nuclear size effect, and quantum electrodynamic corrections. Results for fine structure energy levels for 1s22s22p and 2s2p2 configurations relative to the ground state are reported. The transition wavelengths, transition probabilities, line strengths, and absorption oscillator strengths for 2s22p–2s2p2 electric dipole (E1 transitions are calculated. Both valence and core-valence correlation effects were accounted for through single-double multireference (SD-MR expansions to increasing sets of active orbitals. Comparisons are made with the available data and good agreement is achieved. The values calculated using core–valence correlation are found to be very close to other theoretical and experimental values. The behavior of oscillator strengths as a function of nuclear charge is studied. We believe that our results can guide experimentalists in identifying the fine-structure levels in their future work.

  4. Proton pygmy resonances: predictions for N=20 isotones

    CERN Document Server

    Kim, Y

    2015-01-01

    We study theoretically the low-energy electric-dipole response of N=20 isotones to assess the possibility of detecting a proton-pygmy mode in the near future and to examine the factors that would determine such an outcome. We present results from a quasiparticle random-phase approximation (QRPA) and a continuum random-phase approximation (CRPA), and we compare our results with other calculations of proton-rich nuclei. According to our analysis, enhanced E1 strength is expected energetically well below the giant dipole resonance in the proton-rich isotones. A proton-skin oscillation could develop especially in 46Fe. We identify factors which affect theoretical predictions, besides the equation of state (EoS) of infinite matter: the nucleon separation energy, accordingly the proper description of non localized threshold transitions, and the nucleon effective mass in mean-field treatments. Future measurements of E1 transitions in proton-rich nuclei and comparisons with mirror stable nuclei could help disentangle...

  5. Study of the soft dipole modes in 140Ce via inelastic scattering of 17O

    Science.gov (United States)

    Krzysiek, M.; Kmiecik, M.; Maj, A.; Bednarczyk, P.; Ciemała, M.; Fornal, B.; Grȩbosz, J.; Mazurek, K.; Mȩczyński, W.; Ziȩbliński, M.; Crespi, F. C. L.; Bracco, A.; Benzoni, G.; Blasi, N.; Boiano, C.; Bottoni, S.; Brambilla, S.; Camera, F.; Giaz, A.; Leoni, S.; Million, B.; Morales, A. I.; Nicolini, R.; Pellegri, L.; Riboldi, S.; Vandone, V.; Wieland, O.; De Angelis, G.; Napoli, D. R.; Valiente-Dobon, J. J.; Bazzacco, D.; Farnea, E.; Gottardo, A.; Lenzi, S.; Lunardi, S.; Mengoni, D.; Michelagnoli, C.; Recchia, F.; Ur, C.; Gadea, A.; Huyuk, T.; Barrientos, D.; Birkenbach, B.; Geibel, K.; Hess, H.; Reiter, P.; Steinbach, T.; Wiens, A.; Bürger, A.; Görgen, A.; Guttormsen, M.; Larsen, A. C.; Siem, S.

    2014-05-01

    The main aim of this study was a deeper understanding of the nuclear structure properties of the soft dipole modes in 140Ce, excited via inelastic scattering of weakly bound 17O projectiles. An important aim was to investigate the ‘splitting’ of the PDR into two parts: a low-energy isoscalar component dominated by neutron-skin oscillations and a higher-energy component lying on the tail of the giant dipole resonance of a rather isovector character. This was already observed for this nucleus, investigated in (α, α‧) and (γ, γ‧) experiments. The experiment was performed at Laboratori Nazionali di Legnaro, Italy. Inelastic scattering of 17O ion beam at 20 MeV A-1 was used to excite the resonance modes in the 140Ce target. Gamma-rays were registered by five triple clusters of AGATA-Demonstrator and nine large volume scintillators (LaBr3). The scattered 17O ions were identified by two ΔE - E Si telescopes of the TRACE array mounted inside the scattering chamber. The telescopes consisted of two segmented Si-pad detectors, each of 60 pixels. Very preliminary data have shown a strong domination of the E1 transitions in the ‘pygmy’ region with a character more similar to the one obtained in alpha scattering experiment.

  6. Fission of heavy nuclei by linearly polarized photons

    CERN Document Server

    Khvastunov, V M; Kasyan, S V; Likhachev, V P; Paschuk, S A

    2002-01-01

    Analysing power SIGMA data from photofission of sup 2 sup 3 sup 2 Th, sup 2 sup 3 sup 3 U, sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 6 U, sup 2 sup 3 sup 8 U at the region of giant resonance have been measured using linearly polarized photons. The polarized photons were obtained by plane channelling of electrons in a silicon single crystal. The analysing power SIGMA dependence of the mass number of even-even nucleus has been discovered. Comparison of the analysing power SIGMA values with the data from other experiments with both polarized and unpolarized photon beams was made. It is shown that the analysing power SIGMA values agree with the modern knowledge of E1 transitions but cannot be explain by domination any one of them. It is supposed that analysing power SIGMA is very sensitive to different relative inner and outer fission barrier heights and this affects on SIGMA values for even-even nuclei with the same Z.

  7. p +d →3He+γ reaction with pionless effective field theory

    Science.gov (United States)

    Nematollahi, H.; Bayegan, S.; Mahboubi, N.; Arani, M. Moeini

    2016-11-01

    We study the proton radiative capture by a deuteron with the pionless effective field theory [EFT(π / )] formalism. The calculation of the p d →3Heγ amplitude is considered for the incoming doublet and quartet channels leading to the formation of a 3He. The strong and Coulomb scattering amplitudes for the proton-deuteron (p d ) scattering are included in this study. In this calculation, the properly normalized 3He wave function has been used at each order. We evaluate both M 1 and E 1 transitions in the p d →3Heγ process up to NLO. We calculate the total cross section for the p d →3Heγ process based on the cluster-configuration space and compare it with the experimental data. The cross section results are presented for the incoming proton with the energy 0.5 ≤E ≤3 MeV where the lower and upper limits are chosen for the treatment of Coulomb effects perturbatively and the EFT(π / ) breakdown scale, respectively. No three-body force is needed to renormalize observables up to NLO other than those we have introduced in the p d scattering amplitudes.

  8. Spatial dynamics of laser-induced fluorescence in an intense laser beam: experiment and theory in alkali metal atoms

    CERN Document Server

    Auzinsh, Marcis; Ferber, Ruvin; Gahbauer, Florian; Kalnins, Uldis

    2015-01-01

    We have shown that it is possible to model accurately optical phenomena in intense laser fields by taking into account the intensity distribution over the laser beam. We developed a theoretical model that divided an intense laser beam into concentric regions, each with a Rabi frequency that corresponds to the intensity in that region, and solved a set of coupled optical Bloch equations for the density matrix in each region. Experimentally obtained magneto-optical resonance curves for the $F_g=2\\longrightarrow F_e=1$ transition of the $D_1$ line of $^{87}$Rb agreed very well with the theoretical model up to a laser intensity of around 200 mW/cm$^2$ for a transition whose saturation intensity is around 4.5 mW/cm$^2$. We have studied the spatial dependence of the fluorescence intensity in an intense laser beam experimentally and theoretically. An experiment was conducted whereby a broad, intense pump laser excited the $F_g=4\\longrightarrow F_e=3$ transition of the $D_2$ line of cesium while a weak, narrow probe ...

  9. Study of thermal neutron capture on /sup 32/S

    Energy Technology Data Exchange (ETDEWEB)

    Guo Taichang; Shi Zongren; Zeng Xiantang; Li Guohua; Ding Dazhao

    1985-02-01

    The ..gamma..-ray spectrum of the /sup 32/S (n,..gamma..) reaction at thermal energy measured by using a Ge(Li) detector. Among 86 ..gamma.. rays identified 23 ones are recognized as primary ..gamma..-transitions. The excitation energies of 25 levels and the decay branch ratios are deduced. Three possible levels of 7505.0, 4473.1, and 2884.6 keV were not reported previously. The neutron separation energy of /sup 33/S is determined to be 8641.7 +- 0.6 keV. The thermal neutron capture cross section of /sup 32/S is determined to be 529 +- 26 mb by summing the transition intensities to the ground state of /sup 33/S and comparing with the well known Au (n,..gamma..) cross sections. The partial capture cross section of seven primary E1 transitions are calculated by the formula of the Lane-Lynn direct capture theory and compared with measured values.

  10. Decay spectroscopy of 160Sm: The lightest four-quasiparticle K isomer

    Directory of Open Access Journals (Sweden)

    Z. Patel

    2016-02-01

    Full Text Available The decay of a new four-quasiparticle isomeric state in 160Sm has been observed using γ-ray spectroscopy at the RIBF, RIKEN. The four-quasiparticle state is assigned a 2π⊗2ν π52−[532], π52+[413], ν52−[523], ν72+[633] configuration. The half-life of this (11+ state is measured to be 1.8(4 μs. The (11+ isomer decays into a rotational band structure, based on a (6− ν52−[523]⊗ν72+[633] bandhead, consistent with the gK−gR values. This decays to a (5− two-proton quasiparticle state, which in turn decays to the ground state band. Potential energy surface and blocked-BCS calculations were performed in the deformed midshell region around 160Sm. They reveal a significant influence from β6 deformation and that 160Sm is the best candidate for the lightest four-quasiparticle K isomer to exist in this region. The relationship between reduced hindrance and isomer excitation energy for E1 transitions from multiquasiparticle states is considered with the new data from 160Sm. The E1 data are found to agree with the existing relationship for E2 transitions.

  11. Study of $\\psi(3686)\\to\\pi^0 h_c, h_c\\to\\gamma\\eta_c$ via $\\eta_c$ exclusive decays

    CERN Document Server

    Ablikim, M; Ambrose, D J; An, F F; An, Q; An, Z H; Bai, J Z; Ban, Y; Becker, J; Bertani, M; Bian, J M; Boger, E; Bondarenko, O; Boyko, I; Briere, R A; Bytev, V; Cai, X; Cakir, O; Calcaterra, A; Cao, G F; Cetin, S A; Chang, J F; Chelkov, G; Chen, G; Chen, H S; Chen, J C; Chen, M L; Chen, S J; Chen, Y B; Cheng, H P; Chu, Y P; Cronin-Hennessy, D; Dai, H L; Dai, J P; Dedovich, D; Deng, Z Y; Denig, A; Denysenko, I; Destefanis, M; Ding, W M; Ding, Y; Dong, L Y; Dong, M Y; Du, S X; Fang, J; Fang, S S; Fava, L; Feldbauer, F; Feng, C Q; Ferroli, R B; Fu, C D; Fu, J L; Gao, Y; Geng, C; Goetzen, K; Gong, W X; Gradl, W; Greco, M; Gu, M H; Gu, Y T; Guan, Y H; Guo, A Q; Guo, L B; Guo, Y P; Han, Y L; Harris, F A; He, K L; He, M; He, Z Y; Held, T; Heng, Y K; Hou, Z L; Hu, H M; Hu, J F; Hu, T; Huang, G M; Huang, J S; Huang, X T; Huang, Y P; Hussain, T; Ji, C S; Ji, Q; Ji, X B; Ji, X L; Jiang, L L; Jiang, X S; Jiao, J B; Jiao, Z; Jin, D P; Jin, S; Jing, F F; Kalantar-Nayestanaki, N; Kavatsyuk, M; Kuehn, W; Lai, W; Lange, J S; Li, C H; Li, Cheng; Li, Cui; Li, D M; Li, F; Li, G; Li, H B; Li, J C; Li, K; Li, Lei; Li, Q J; Li, S L; Li, W D; Li, W G; Li, X L; Li, X N; Li, X Q; Li, X R; Li, Z B; Liang, H; Liang, Y F; Liang, Y T; Liao, G R; Liao, X T; Liu, B J; Liu, C L; Liu, C X; Liu, C Y; Liu, F H; Liu, Fang; Liu, Feng; Liu, H; Liu, H B; Liu, H H; Liu, H M; Liu, H W; Liu, J P; Liu, K Y; Liu, Kai; Liu, P L; Liu, Q; Liu, S B; Liu, X; Liu, X H; Liu, Y B; Liu, Z A; Liu, Zhiqiang; Liu, Zhiqing; Loehner, H; Lu, G R; Lu, H J; Lu, J G; Lu, Q W; Lu, X R; Lu, Y P; Luo, C L; Luo, M X; Luo, T; Luo, X L; Lv, M; Ma, C L; Ma, F C; Ma, H L; Ma, Q M; Ma, S; Ma, T; Ma, X Y; Ma, Y; Maas, F E; Maggiora, M; Malik, Q A; Mao, Y J; Mao, Z P; Messchendorp, J G; Min, J; Min, T J; Mitchell, R E; Mo, X H; Morales, C Morales; Motzko, C; Muchnoi, N Yu; Muramatsu, H; Nefedov, Y; Nicholson, C; Nikolaev, I B; Ning, Z; Olsen, S L; Ouyang, Q; Pacetti, S; Park, J W; Pelizaeus, M; Peng, H P; Peters, K; Ping, J L; Ping, R G; Poling, R; Prencipe, E; Qi, M; Qian, S; Qiao, C F; Qin, X S; Qin, Y; Qin, Z H; Qiu, J F; Rashid, K H; Rong, G; Ruan, X D; Sarantsev, A; Schaefer, B D; Schulze, J; Shao, M; Shen, C P; Shen, X Y; Sheng, H Y; Shepherd, M R; Song, X Y; Spataro, S; Spruck, B; Sun, D H; Sun, G X; Sun, J F; Sun, S S; Sun, Y J; Sun, Y Z; Sun, Z J; Sun, Z T; Tang, C J; Tang, X; Tapan, I; Thorndike, E H; Toth, D; Ullrich, M; Varner, G S; Wang, B; Wang, B Q; Wang, K; Wang, L L; Wang, L S; Wang, M; Wang, P; Wang, P L; Wang, Q; Wang, Q J; Wang, S G; Wang, X L; Wang, Y D; Wang, Y F; Wang, Y Q; Wang, Z; Wang, Z G; Wang, Z Y; Wei, D H; Weidenkaff, P; Wen, Q G; Wen, S P; Werner, M; Wiedner, U; Wu, L H; Wu, N; Wu, S X; Wu, W; Wu, Z; Xia, L G; Xiao, Z J; Xie, Y G; Xiu, Q L; Xu, G F; Xu, G M; Xu, H; Xu, Q J; Xu, X P; Xu, Z R; Xue, F; Xue, Z; Yan, L; Yan, W B; Yan, Y H; Yang, H X; Yang, Y; Yang, Y X; Ye, H; Ye, M; Ye, M H; Yu, B X; Yu, C X; Yu, J S; Yu, S P; Yuan, C Z; Yuan, Y; Zafar, A A; Zallo, A; Zeng, Y; Zhang, B X; Zhang, B Y; Zhang, C C; Zhang, D H; Zhang, H H; Zhang, H Y; Zhang, J Q; Zhang, J W; Zhang, J Y; Zhang, J Z; Zhang, S H; Zhang, X J; Zhang, X Y; Zhang, Y; Zhang, Y H; Zhang, Y S; Zhang, Z P; Zhang, Z Y; Zhao, G; Zhao, H S; Zhao, J W; Zhao, K X; Zhao, Lei; Zhao, Ling; Zhao, M G; Zhao, Q; Zhao, S J; Zhao, T C; Zhao, X H; Zhao, Y B; Zhao, Z G; Zhemchugov, A; Zheng, B; Zheng, J P; Zheng, Y H; Zhong, B; Zhong, J; Zhou, L; Zhou, X K; Zhou, X R; Zhu, C; Zhu, K; Zhu, K J; Zhu, S H; Zhu, X L; Zhu, X W; Zhu, Y C; Zhu, Y M; Zhu, Y S; Zhu, Z A; Zhuang, J; Zou, B S; Zou, J H

    2012-01-01

    The process $\\psi(3686) \\to \\pi^0 h_c, h_c \\to \\gamma \\eta_c$ has been studied with a data sample of $106 \\pm 4$ million $\\psi(3686)$ events collected with the BESIII detector at the BEPCII storage ring. The mass and width of the $P$-wave charmonium spin-singlet state $h_c(^1P_1)$ are determined by simultaneously fitting distributions of the $\\pi^0$ recoil mass for 16 exclusive $\\eta_c$ decay modes. The results, $M(\\hc) = 3525.31 \\pm 0.11 {\\rm (stat.)} \\pm 0.14 {\\rm (syst.)}$\\,MeV/$c^2$ and $\\Gamma(\\hc) = 0.70 \\pm 0.28 \\pm 0.22$\\,MeV, are consistent with and more precise than previous measurements. We also determine the branching ratios for the 16 exclusive $\\eta_c$ decay modes, five of which have not been measured previously. New measurements of the $\\eta_c$ line-shape parameters in the $E1$ transition $h_c\\to\\gamma\\eta_c$ are made by selecting candidates in the $h_c$ signal sample and simultaneously fitting the hadronic mass spectra for the 16 $\\eta_c$ decay channels. The resulting $\\eta_c$ mass and width v...

  12. Study of some properties of 's' neutron resonance parameters for target nuclei I = 1/2 and I = 3/2 in function of spin value J = I + 1/2 in the energy range 1 {yields} 5000 eV; Etude de quelques proprietes des parametres de resonances des neutrons ''s'' pour des noyaux cibles I = 1/2 et I = 3/2 en fonction de la valeur du spin J = I + 1/2 dans le domaine d'energie 1 eV {yields} 5000 eV

    Energy Technology Data Exchange (ETDEWEB)

    Julien, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-05-15

    Different kinds of experiments and analysis methods allowing to achieve neutron resonances parameters in the low energy range (1 eV {yields} 5000 eV) are described. A great deal of effort to improve experimental conditions and data processing in order to know the spin value J = I {+-} 1/2 has been spent. The time of flight method was used. A few target nuclei I = 3/2 and 1 = 1/2 have been studied. For I = 3/2 (Ga, As, 3r, Au) we find S{sub o} J = 2 {approx_equal} 2 S{sub o} J = 1 and S{sub o} J = 1 {approx_equal} S{sub o} J = 0 for I = 1/2 (Tm, Pt) but {sup 77}Se. Fluctuations of the total radiative width {gamma}{sub {gamma}} depend on the spin value I = I {+-} 1/2 when E1 transition, are enhanced for one of the both spin states. The magnitude of these fluctuations can be explained of the strength of E1 transitions (E{sub {gamma}} {approx} 7 MeV) is supposed to be proportional to E{sup 5}{sub {gamma}} instead of E{sup 3}{sub {gamma}}. The distribution of levels spacings against spin value J are considered and are compared to theoretical predictions. (author) [French] On decrit les differentes methodes d'analyse permettant d'obtenir les parametres des resonances de neutron dans le domaine d'energie 1 eV {yields} 5000 eV. Un effort particulier a ete fait pour connaitre la valeur du spin J = I {+-} 1/2. Les types d'experience et les analyses des donnees, developpes et ameliores pour determiner J sont decrits. Les resultats obtenus ont permis l'etude de differentes proprietes en fonction du spin J. On trouve: S{sub o} J 2 {approx_equal} 2 S{sub o} J = 1 pour les noyaux I = 3/2 etudies (Ga, As, Br, Au) et S{sub o} J = 1 {approx_equal} S{sub o} J = 0 Pour le Tm et {sup 195}Pt de spin I = 1/2. On constate que les largeurs radiatives totales {gamma}{sub {gamma}} fluctuent si des transitions E1 aux premiers etats excites sont favorisees. Ces fluctuations peuvent etre expliquees si on suppose que les intensites de ces transitions sont

  13. NUSTART: A PC code for NUclear STructure And Radiative Transition analysis and supplementation

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, G.L.; Gardner, D.G.; Gardner, M.A.

    1990-10-01

    NUSTART is a computer program for the IBM PC/At. It is designed for use with the nuclear reaction cross-section code STAPLUS, which is a STAPRE-based CRAY computer code that is being developed at Lawrence Livermore National Laboratory. The NUSTART code was developed to handle large sets of discrete nuclear levels and the multipole transitions among these levels; it operates in three modes. The Data File Error Analysis mode analyzes an existing STAPLUS input file containing the levels and their multipole transition branches for a number of physics and/or typographical errors. The Interactive Data File Generation mode allows the user to create input files of discrete levels and their branching fractions in the format required by STAPLUS, even though the user enters the information in the (different) format used by many people in the nuclear structure field. In the Branching Fractions Calculations mode, the discrete nuclear level set is read, and the multipole transitions among the levels are computed under one of two possible assumptions: (1) the levels have no collective character, or (2) the levels are all rotational band heads. Only E1, M1, and E2 transitions are considered, and the respective strength functions may be constants or, in the case of E1 transitions, the strength function may be energy dependent. The first option is used for nuclei closed shells; the bandhead option may be used to vary the E1, M1, and E2 strengths for interband transitions. K-quantum number selection rules may be invoked if desired. 19 refs.

  14. Self-consistent quasiparticle formulation of a multiphonon method and its application to the neutron-rich O20 nucleus

    Science.gov (United States)

    De Gregorio, G.; Knapp, F.; Lo Iudice, N.; Vesely, P.

    2016-04-01

    A Bogoliubov quasiparticle formulation of an equation-of-motion phonon method, suited for open-shell nuclei, is derived. Like its particle-hole version, it consists of deriving a set of equations of motions whose iterative solution generates an orthonormal basis of n -phonon states (n =0 ,1 ,2 ,... ), built of quasiparticle Tamm-Dancoff phonons, which simplifies the solution of the eigenvalue problem. The method is applied to the open-shell neutron-rich O20 for illustrative purposes. A Hartree-Fock-Bogoliubov canonical basis, derived from an intrinsic two-body optimized chiral Hamiltonian, is used to derive and solve the eigenvalue equations in a space encompassing a truncated two-phonon basis. The spurious admixtures induced by the violation of the particle number and the center-of-mass motion are eliminated to a large extent by a Gram-Schmidt orthogonalization procedure. The calculation takes into account the Pauli principle, is self-consistent, and is parameter free except for the energy cutoff used to truncate the two-phonon basis, which induces an increasing depression of the ground state through its strong coupling to the quasiparticle vacuum. Such a cutoff is fixed so as to reproduce the first 1- level. The two-phonon states are shown to enhance the level density of the low-energy spectrum, consistently with the data, and to induce a fragmentation of the E 1 strength which, while accounting for the very low E 1 transitions, is not sufficient to reproduce the experimental cross section in the intermediate energy region. This and other discrepancies suggest the need of including the three-phonon states. These are also expected to offset the action of the two phonons on the quasiparticle vacuum and, therefore, free the calculation from any parameter.

  15. The Search for the Emission of a CP-Violating E1 Photon in the KL → π+π-γ Decay

    Energy Technology Data Exchange (ETDEWEB)

    Shields, John Michael [Univ. of Virginia, Charlottesville, VA (United States)

    2005-08-01

    A search for the CP-violating electric dipole (E1) direct emission contribution to the KL → π+π-γ decay is performed using data from the 1997 KTeV/E832 experiment. Because the KL → π+π-γ decay mode is massively dominated by the CP-violating inner bremsstrahlung (IB) and the CP-conserving magnetic dipole (M1) direct emission processes, previous analyses have neglected the E1 contribution. Therefore, this measurement is the first attempt to directly quantify the size of the E1 decay process. This E1 transition is one of the very few CP-violating processes that is accessible to experiment and, in principle, will produce new insights into the structure of the neutral kaon. The result of this analysis is that the E1 contribution is below the threshold of sensitivity, and therefore an upper bound of |gE1| < 0.14 (90% CL) is reported. In the process of obtaining this upper limit, high resolution measurements of fit parameters (~gM1 and a1/a2) associated with the size and shape of the M1 direct emission peak are also extracted. The fit results for these parameters: ~gM1 = 1.229 ± 0.035 (stat) ± 0.087 (syst); a1/a2 = -0.733 ± 0.007 (stat) ± 0.014 (syst) are in strong agreement with previous measurements.

  16. Theoretical study on the low-lying excited states of the phosphorus monoiodide (PI) including the spin-orbit coupling

    Science.gov (United States)

    Zhang, Xiaomei; Liu, Xiaoting; Liang, Guiying; Li, Rui; Xu, Haifeng; Yan, Bing

    2016-01-01

    The potential energy curves (PECs) of the 22 Λ-S states of the phosphorus monoiodide (PI) molecule have been calculated at the level of MRCI+Q method with correlation-consistent quadruple-ζ quality basis set. The spectroscopic constants of the bound states are determined, which well reproduce the available measurements. The metastable a1Δ state has been reported for the first time, which lies between the X3Σ- and b1Σ+ states and have much deeper well than the ground state. The R-dependent spin-orbit (SO) matrix elements are calculated with the full-electron Breit-Pauli operator. Based on the SO matrix elements, the perturbations that the 23Π state may suffer from are analyzed in detail. The SOC effect makes the original Λ-S states split into 51 Ω states. In the zero-field splitting of the ground state X3Σ-, the spin-spin coupling contribution (2.23 cm-1) is found to be much smaller compared to the spin-orbit coupling contribution (50 cm-1). The avoided crossings between the Ω states lead to much shallower potential wells and the change of dissociation relationships of the states. The Ω-state wavefunctions are analyzed depending on their Λ-S compositions, showing the strong interactions among several quasidegenerate Λ-S states of the same total SO symmetry. The transition properties including electric dipole (E1), magnetic dipole (M1), and electric quadrupole (E2) transition moments (TMs), the Franck-Condon factors, the transition probabilities and the radiative lifetimes are computed for the transitions between Ω components of a1Δ and b1Σ+ states and ground state. The transition probabilities induced by the E1, E2, and M1 transitions are evaluated. The E2 makes little effect on transition probabilities. In contrast, the E1 transition makes the main contribution to the transition probability and the M1 transition also brings the influence that cannot be neglected. Finally, the radiative lifetimes are determined with the transition moments including E