共查询到20条相似文献,搜索用时 31 毫秒
1.
Sayipjamal Dulat Bing-Song Zou 《The European Physical Journal A - Hadrons and Nuclei》2005,26(1):125-134
With accumulation of high statistics data at BES and CLEO-c, many new interesting channels can get enough statistics for partial-wave
analysis (PWA). Among them, ψ↦γpˉ,γΛˉ,γΣˉ,γΞˉ channels provide a good place for studying baryon-antibaryon interactions; the double radiative decays ψ↦γγV with V ≡ ρ,ω,φ have a potential to provide information on the flavor content of any meson resonances (R) with positive charge parity
(C = +) and mass above 1 GeV through ψ↦γR↦γγV; ψ(2s)↦γχc0,1,2 with χc0,1,2↦Kˉπ+π- and 2π+2π- decays are good processes to study χcJ charmonium decays. Using the covariant tensor formalism, here we provide theoretical PWA formulae for these channels. 相似文献
2.
W. Zhang S. You C. Sun Y. Zhang J. Xu Z. Ma Y. Feng H. Liu P. Quinet é. Biémont Z. Dai 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(1):1-8
First laser spectroscopic measurements of the 6s5d3D1-6s6p1P1 and 6s5d3D2-6s6p1P1 transitions in several isotopes of atomic barium have been performed. The hyperfine structure of these transitions was optically
resolved and isotope shifts for even and odd isotopes were determined. The isotope shifts show a deviation from their expected
behavior for odd isotopes in an analysis based on King-plots. This observation puts atomic structure calculations at test
because available theories do not predict this. A profound understanding of the wavefunctions for heavy alkaline earth systems
like barium (Ba) and radium (Ra) is essential for a theoretical evaluation of their sensitivity to fundamental symmetry breaking
effects such as they could be observed, e.g., through permanent electric dipole moments. Further the absolute frequency of
the 6s2
1S0-6s6p3P1 intercombination line in 138Ba was determined to be 12 636.6232(1) cm-1. 相似文献
3.
A. Yu. Buki I. S. Timchenko N. G. Shevchenko 《The European Physical Journal A - Hadrons and Nuclei》2012,48(2):17
The Coulomb sums S
L(q) of the 6Li nucleus have been obtained from electron scattering measurements at 3-momentum transfers q = 1.125–1.625 fm−1. It is found that at q > 1.35 fm−1 the Coulomb sum of the nucleus becomes saturated: S
L(q) = 1 . 相似文献
4.
R. Álvarez-Rodrıguez E. Garrido A. S. Jensen D. V. Fedorov H. O. U. Fynbo 《The European Physical Journal A - Hadrons and Nuclei》2007,31(3):303-317
The hyperspherical adiabatic expansion is combined with complex scaling and used to calculate low-lying nuclear resonances
of 12C in the 3α model. We use Ali-Bodmer potentials and compare results for other potentials α-α with similar 8Be properties. A three-body potential is used to adjust the 12C resonance positions to desired values extending the applicability of the method to many-body systems decaying into three
α-particles. For natural choices of three-body potentials we find 14 resonances below the proton separation threshold, i.e. two 0+, three 2+, two 4+, one of each of 1±, 2-, 3±, 4-, and 6+. The partial-wave decomposition of each resonance is calculated as a function of the hyperradius. Strong variation is found
from small to large distance. The connection to previous experimental and theoretical results is discussed and agreements
as well as disagreements are emphasized. 相似文献
5.
E. S. Mironchuk 《Bulletin of the Lebedev Physics Institute》2010,37(6):180-181
A method for determining the relative concentration of 13C/12C isotopes by the vibrational-rotational spectrum of CO2 molecule absorption in the range near 2 μm was proposed. The use of the entire region of the diode laser tuning (∼7 cm−1) and multivariate linear regression for spectrum approximation allow measurements at atmospheric pressure. The laser frequency
is additionally stabilized by injection current variation. The ultimate sensitivity of the setup, determined by the plot of
the squared Alan variance, is 0.03% for 2-min signal acquisition. The system does not contain elements cooled by liquid nitrogen
and can be used in medical diagnostics. 相似文献
6.
The trielectronic recombination of an In+ (4d
105s
2
1
S
0) ion in collisions with slow electrons, including the two-electron excitation of the 5s2 core of the ion with the simultaneous capture of the triply excited 5p
3 intermediate autoionizing state with its subsequent radiative stabilization 5p
3 → 5s5p
2 + hν has been detected and experimentally examined for the first time. The maximum effective cross section of trielectronic recombination
is 1.6 × 10−16 cm2, which is comparable to the effective cross sections for both dielectronic recombination and electron excitation of the In+ ion. 相似文献
7.
I. N. Boboshin V. V. Varlamov B. S. Ishkhanov E. A. Romanovsky 《Physics of Atomic Nuclei》2007,70(8):1363-1368
New information about energies and occupation probabilities of neutron and proton single-particle (hole) subshells in even—even
nuclei was obtained in previous studies applying the method of putting into correspondence all available data on one-nucleon
pickup and stripping reactions. The most important and interesting resultwas identification of several nuclei as new magic
ones. Namely, itwas found that a filling of the neutron 2d
5/2 subshell in 96Zr makes this nuclide a magic one. Moreover, changes in proton subshell energies with increasing neutron number N are accompanied by an increasing energy gap between closed 2p
1/2 and empty 1g
9/2 subshells. Thus, the neutron number N = 56 appears to be a magic one if the proton number Z is equal to 40. The proton number Z = 40 manifests properties of the magic number in 96Zr. Therefore, 96Zr was identified as a new double-magic nucleus. Further investigations revealed that the energy of the first 2+ state E(2
1
+
) in 96Zr is much higher than that in the neighboring isotopes and isotones, whereas the ratio E(4
1
+
)/E(2
1
+
) and the quadrupole deformation parameter β2 are, vice versa, clearly lower. Moreover, the A dependence of the neutron separation energy B(n) in Zr isotopes has an irregularity at N = 56 which is typical of magic nuclei. As a result of these investigations, it was found that, near the Fermi energy, there
are two closed subshells with the same (and large) angular momentum j = 5/2 (viz. π1f
5/2 and ν2d
5/2). We call this situation the jj connection. The magic numbers under discussion (Z = 40 and N = 56) are achieved at the points where both subshells are closed, and in addition, the closed subshell with j = 1/2, π2p
1/2, occurs above the proton π1f
5/2 subshell. This looks like a result of some additional attractive proton-neutron interaction. It was found that application
of this scheme (jj connection) to other subshells reveals several other new magic nuclei: 54Ca (closed π1d
3/2 and ν2p
3/2 together with closed ν2p
1/2), 30S and 30Si (closed π1d
5/2 and ν1d
5/2 together with closed (π/ν)2s
1/2), and 14O and 14C (closed π1p
3/2 and ν1p
3/2 together with closed ν2p
1/2).
The text was submitted by the authors in English. 相似文献
8.
H. Naik R.J. Singh R.H. Iyer 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):495-507
Charge distribution studies for heavy-mass fission products were carried out in the fast-neutron-induced fission of 232Th, 238U, 240Pu and 244Cm using radiochemical and gamma-ray spectrometric techniques. The width parameter( σZ/σA), the most probable charge/mass ( Z
P/A
P), the charge polarization (ΔZ) and the slope of charge polarization [ δ(ΔZ)/δA
′] as a function of the fragment mass (A
′) were deduced. The average charge dispersion parameter ( 〈σZ〉) and proton odd-even effect ( δp) were also obtained for these fissioning systems. The 〈σZ〉 and δp values in the fissioning systems 241Pu * and 245Cm * were determined for the first time. The δ(ΔZ)/δA
′ value is also determined for the first time in the fissioning systems 239U * , 241Pu * and 245Cm * . These data along with the literature data for even-Z fissioning systems such as 230Th * , 232Th * , 233U * , 234U * , 236U * , 238U * , 239Pu * , 240Pu*, 242Pu * , 246Cm * , 250Cf * and 252Cf(SF) are discussed in terms of nuclear structure effect and dynamics of descent from the saddle to the scission point. The
role of the excitation energy in low-energy fission is also discussed.
Received: 26 July 2002 / Accepted: 3 December 2002 / Published online: 3 April 2003
RID="a"
ID="a"Present address: Emeritus Scientist (CSIR) Bhabha Atomic Research Centre, Nuclear Recycle Group, WIP Building, Trombay, Mumbai-400085, India;
e-mail: rhiyer@magnum. barc.ernet.in
Communicated by D. Schwalm 相似文献
9.
Within the framework of the single-channel approximation, an {αtd} model of the 9
Be nucleus is presented. A comparative analysis of the t 6
Li wave functions describing relative motion of bound states constructed in {ααn} and {αtd} cluster representations is carried out on the example of calculations of the 9
Be(γ,t0)6
Li process characteristics.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 85–89, January, 2008. 相似文献
10.
A. Sibirtsev J. Haidenbauer H. -W. Hammer U. -G. Meißner 《The European Physical Journal A - Hadrons and Nuclei》2007,32(2):229-241
We utilize existing inclusive data on K+-meson momentum spectra of the reaction pp→K
+
X at T
p = 2.3-2.85GeV to deduce total cross-sections for pp→K
+
Σ
+
n. The method used to extract those cross-sections is explained and discussed in detail. Our result for T
p = 2.85GeV is consistent with the data point from a direct measurement at the same beam energy. The cross-section obtained
for T
p = 2.3GeV is with 13.7±2.3μb considerably smaller than the value found in a recent experiment by the COSY-11 Collaboration
at a somewhat lower beam energy, indicating that the pp→K
+
Σ
+
n reaction cross-section could exhibit a rather unusual energy dependence. 相似文献
11.
Ion cluster desorption yields from LiF were measured at PUC-Rio with ≈0.1 MeV/u N
q+ (q = 2,4,5,6) ion beams by means of a time-of-fight (TOF) mass spectrometer. A 252Cf source mounted in the irradiation chamber allows immediate comparison of cluster emissions induced by ≈65 MeV fission fragments
(FF). Emission of (LiF)
n
Li+ clusters are observed for both the N beams and the 252Cf fission fragments. The observed cluster size n varies from 1 to 6 for N
q+ projectiles and from 1 to ≈40 for the 252Cf-FF. The size dependence of the Y(n) distributions suggests two cluster formation regimes: (i) recombination process in the outgoing gas phase after impact and
(ii) emission of pre-formed clusters from the periphery of the impact site. The corresponding distribution of ejected negative
cluster ions (LiF)
n
F− closely resembles that of the positive secondary (LiF)
n
Li+ ions. The desorption yields of positive ions scale as Y(n) ∼ q
5. A calculation with the CASP code shows that this corresponds to a cubic scaling ∼S
e
3 with the electronic stopping power S
e
, as predicted by collective shock wave models for sputtering and models involving multiple excitons (Frenkel pair sputtering).
We discuss possible interpretations of the functional dependence of the evolution of the cluster emission yield Y(n) with cluster size n, fitted by a number of statistical distributions. 相似文献
12.
A. S. Kachan I. V. Kurguz I. S. Kovtunenko V. M. Mischenko V. A. Panin 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(11):1506-1510
The γ decay of the resonance-like structure observed in the 30Si(pγ)31P reaction in the energy range E
p = 1.4–2.7 MeV of accelerated protons has been investigated. The excitation function of this reaction and the spectra and
angular distributions of the γ rays formed in the decay of resonances with E
p = 1482, 2350, and 2505 keV have been measured. The M1 resonance on the ground and the first excited states of 31P with E
p = 1266 keV is identified. The total strength of the M1 resonance on the ground state of this nucleus is determined. The position and total strength of this resonance on the ground
state are explained taking into account pairing forces. 相似文献
13.
J. He B. Saghai Z. Li Q. Zhao J. Durand 《The European Physical Journal A - Hadrons and Nuclei》2008,35(3):321-324
A constituent quark model is developed for the reaction γp → ηp , allowing us to investigate all available data for differential cross-sections as well as single polarization asymmetries
(beam and target) by including all of the PDG, one to four star, nucleon resonances (S11, P11, P13, D13, D15, F15, F17, G17, G19, H19, I1,11, and K1,13). Issues related to the missing resonances are also briefly discussed by examining possible contributions from several new
resonances (S11, P11, P13, D13, D15, and H1,11). 相似文献
14.
We have grown crystals Na0.4Y0.6F2.2:Ho3+ (NYF:Ho3+) by the Bridgman-Stockbarger method. The optical spectra and luminescence kinetics of NYF:Ho3+ crystals have been studied. Based on the analysis of low-temperature absorption spectra, we determine the structure of the
Stark splitting of holmium levels in NYF:Ho3+ crystals. From absorption spectra examined at T = 300 K, we calculate absorption cross-section spectra and oscillator strengths of transitions from the ground state of holmium
to excited multiplets. We show that the absorption spectra of NYF:Ho3+ crystals consist of broad bands that lie in the UV, visible, and near-IR ranges. The most intense bands are observed in the
visible range, they correspond to transitions 5
I
8 → (5
F
1, 5
G
6) and 5
I
8 → (5
F
4, 5
S
2), and their maximal absorption cross sections are σabsmax (λ = 450.3 nm) = 1.16 × 10−20 cm2 and σabsmax (λ = 535.1 nm) = 0.9 × 10−20 cm2. The intensity parameters Ω
t
have been calculated by the Judd-Ofelt method taking into account 10, 12, and 20 transitions from the 5
I
8 ground state to excited multiplets. We show that, with an increasing number of transitions taken into account in the calculation,
the parameters Ω
t
somewhat increase. For 20 transitions, we have obtained the following intensity parameters: Ω2 = 0.97 × 10−20, Ω4 = 1.74 × 10−20, and Ω6 = 1.15 × 10−20 cm2. With these parameters, we have calculated the probabilities of radiative transitions, the radiative lifetimes, and the branching
ratios. The rates of multiphoton nonradiative transitions have been estimated. The luminescence decay kinetics from excited
holmium levels 5
F
3 (5
F
4, 5
S
2) and 5
F
5 have been studied upon selective excitation in the range of 490 nm, and the lifetimes of these levels have been experimentally
determined. We find that the calculated and experimental rates of radiative and nonradiative relaxation from excited holmium
levels agree well with each other. We show that, upon pumping in the range of 490 nm, the multiplet (5
F
4, 5
S
2) is populated as a result of the radiative and nonradiative excitation relaxation from the 5
F
3 level, while the lower-lying 5
F
5 level is populated due to direct radiative transitions 5
F
3, 2 → 5
F
5, obviating the cascade scheme 5
F
3 → (5
F
4, 5
S
2) ↝ 5
F
5. We conclude that NYF:Ho3+ crystals are processable; admit doping by holmium in high concentrations (up to 100%); and, with respect to all their radiative
characteristics, can be considered as potential active media for solid-state continuously tunable lasers in the IR and visible
ranges. 相似文献
15.
A. Gasparyan J. Haidenbauer C. Hanhart K. Miyagawa 《The European Physical Journal A - Hadrons and Nuclei》2007,32(1):61-67
The prospects of utilizing the strangeness production reaction γd→K
+
Λn for the determination of the Λn low-energy scattering parameters are investigated. The spin observables that need to be measured in order to isolate the
Λn singlet (1
S
0) and triplet (3
S
1) states are identified. Possible kinematical regions where the extraction of the Λn scattering lengths might be feasible are discussed. 相似文献
16.
I. V. Glavanakov P. Grabmayr Yu. F. Krechetov A. N. Tabachenko 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(6):747-749
Experimental research on positive-pion photoproduction on the oxygen nucleus in the 16O(γ, π+p) reaction at high recoil momenta of the residual nuclear system was performed. The yield for the 16O(γ, π+p) reaction was analyzed using a model that takes Δ-isobar configurations in nuclei ground states into account, together with
the earlier-measured yield of the12C(γ, π+p) reaction. The estimated number of isobars per nucleon N
Δ = 0.012 ± 0.005 was obtained for the 12C nucleus, and 16O N
Δ = 0.018 ± 0.004 was obtained for the 16O nucleus. 相似文献
17.
J.H. Huang X.H. Gong Y.J. Chen Y.F. Lin J.S. Liao X.Y. Chen Z.D. Luo Y.D. Huang 《Applied physics. B, Lasers and optics》2007,89(1):73-80
Polarized spectral properties of Er3+:NaGd(WO4)2 single crystal are reported. The crystal was grown by the Czochralski method. The Judd–Ofelt theory was applied to analyze
the polarized absorption spectra and then calculate the spontaneous emission probabilities, radiative lifetimes, and branching
ratios. Fluorescence decay curves of the 4
I
13/2, 4
I
11/2, and 4
S
3/2 multiplets for the Er3+ ions were measured. Stimulated emission cross-sections of the 4
I
13/2→4
I
15/2 transition obtained by the Fuchtbauer–Ladenberg formula and the reciprocity method were compared. Multi-phonon relaxation
rates of the crystal were estimated. Green up-conversion fluorescence around 531 and 552 nm was observed, and the possible
up-conversion mechanisms were proposed.
PACS 78.20.-e; 42.70.Hj 相似文献
18.
N. Burtebayev S. V. Artemov B. A. Duisebayev Zh. K. Kerimkulov S. B. Kuranov S. B. Sakuta 《Physics of Atomic Nuclei》2010,73(5):746-756
At an energy of 25 MeV and in the angular range 7°−175° in the laboratory frame, angular distributions were measured for elastic
deuteron scattering on 6Li nuclei and for the respective inelastic-scattering processes accompanied by the transitions to the ground state (1+) of
the 6Li nucleus and to its excited state at E
x
= 2.186 MeV (J
π = 3+). The resulting data were analyzed on the basis of the optical model of the nucleus and the coupled-reaction-channel method
with allowance for the mechanism of alpha-particle-cluster exchange. It is shown that only upon including, in the analysis,
channel coupling and the exchange mechanism can the experimental cross sections for elastic and inelastic scattering be reproduced
over the entire range of angles. 相似文献
19.
The torus group (S
1)ℓ+1 has a canonical action on the odd-dimensional sphere S
q
2ℓ+1. We take the natural Hilbert space representation where this action is implemented and characterize all odd spectral triples
acting on that space and equivariant with respect to that action. This characterization gives a construction of an optimum
family of equivariant spectral triples having nontrivial K-homology class thus generalizing our earlier results for SU
q
(2). We also relate the triple we construct with the C
*-extension
相似文献
20.
We report the results of the Monte Carlo study of the method to determine the CKM angle φ3 using Dalitz plot analysis of D0 produced in B±→DK± decay. Our main goal is to find the optimal strategy for a model-independent φ3 extraction. We find that the analysis using decays of CP-tagged D mesons only cannot provide a completely model-independent
measurement in the case of a limited data sample. The procedure involving binned analysis of B±→DK± and ψ(3770)→(K0
Sπ+π-)D(K0
Sπ+π-)D decays is proposed which, in contrast, allows not only to reach the φ3 precision comparable to an unbinned model-dependent fit, but also provides an unbiased measurement with currently available
data.
PACS 11.30.Er; 12.15.Hh 相似文献