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1.
The two-neutrino positron double-beta decay of 106Cd for the 0 + 0+ transition has been studied in the Hartree-Fock-Bogoliubov model in conjunction with the summation method. In the first step, the reliability of the intrinsic wave functions of 106Cd and 106Pd nuclei has been tested by comparing the theoretically calculated results for yrast spectra, reduced B(E2: 0+ 2+) transition probabilities, quadrupole moments Q(2+) and gyromagnetic factors g(2+) with the available experimental data. In the second step, the nuclear transition matrix element M2 and the half-life T1/22 for the 0 + 0+ transition have been calculated with these wave functions. Moreover, we have studied the effect of deformation on the nuclear transition matrix element M2. 相似文献
2.
Cross-sections, beam asymmetries, and recoil polarisations for the reactions γp → K
+Λ;γp → K
+Σ0, and γp → K
0Σ+ have been measured by the SAPHIR, CLAS, and LEPS Collaborations with high statistics and good angular coverage for centre-of-mass
energies between 1.6 and 2.3 GeV. The combined analysis of these data with data from π and η photoproduction reveals evidence
for new baryon resonances in this energy region. A new P11 state with mass 1840 MeV and width 140 MeV was observed contributing to most of the fitted reactions. The data demand the
presence of two D13 states at 1875 and, optimistically, at 2170 MeV. 相似文献
3.
A. B. Arbuzov E. A. Kuraev M. K. Volkov 《The European Physical Journal A - Hadrons and Nuclei》2011,47(9):103
The processes of electron-positron annihilation into π0γ and into π′(1300)γ are considered within an extended NJL model. The intermediate vector mesons ρ
0, ω
ρ′(1450), and ω(1420) are taken into account. The latter two mesons are treated as the first radial excited states. They are incorporated
into the NJL model by means of a polynomial form factor. Numerical predictions for the cross-sections of these processes are
received for the center-of-mass energies below 2 GeV. Our results for the π0γ production are in agreement with experimental data obtained in the energy region 600–1020 MeV. 相似文献
4.
Combining the Okubo-Zweig-Iizuka rule in the decay φ→ρπ→π+π?π0 with the ρ→4π decay amplitudes, we calculate the φ→2π+2π?π0 and φ→π+π?3π0 ones. The partial widths of the above φ decays are evaluated, and the excitation curves in e+e? annihilation are obtained, assuming reasonable particular relations among the parameters characterizing the anomalous terms of the HLS Lagrangian. The evaluated branching ratios Bφ→π+π?3π0 ≈ 2 × 10?7 and Bφ→2π+2π?π0 ≈ 7 × 10?7 are such that, with the luminosity L=500 pb?1 attained at DAΦNE φ factory, one may already possess about 1685 events of the decays φ→5π. 相似文献
5.
A. S. Ignatov A. N. Mushkarenkov V. G. Nedorezov 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(6):703-706
The reaction of π0π+ photoproduction on free and quasi-free protons with γ-ray energies from 0.5 to 1.5 GeV has been studied. Its cross section was measured in the range θ π 0 ≥ 20°. The distributions of π0π+, π0n, and π+n invariant masses were analyzed. The experiment was performed using the Compton back-scattered γ-ray beam at the GRAAL facility (Grenoble, France), applying liquid deuterium and hydrogen targets and a large-aperture (almost 4π) detector. Particular attention was paid to analysis of systematic errors related to the neutron detection efficiency. 相似文献
6.
We perform a theoretical study based on dispersion relations of the reaction γγ → π
0
π
0 emphasizing the low-energy region. We discuss how the ƒ
0(980) signal emerges in γγ → ππ within the dispersive approach and how this fixes to a large extent the phase of the isoscalar S-wave γγ → ππ amplitude above the threshold. This allows us to make sharper predictions for the cross-section at lower energies and our results could then
be used to distinguish between different ππ isoscalar S-wave parameterizations with the advent of new precise data on ππ → π
0
π
0. We compare our dispersive approach with an updated calculation employing the unitary chiral perturbation theory (U
gC
PT). We also pay special attention to the role played by the σ-resonance in γγ → ππ and calculate its coupling and width to γγ, for which we obtain Γ(σ → γγ) = (1.68 ± 0.15) keV. 相似文献
7.
I.?Man?ev 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(2):213-218
The total cross sections for charge transfer in Li2+-H and He+-He+ collisions have been calculated, using the four body first Born approximation with correct boundary conditions (CB1-4B) and
four body continuum distorted wave method (CDW-4B) in the energy range 10–5000 keV/amu. The role of dynamic electron correlations
is examined as a function of the impact energy. The present results call for additional experimental data at higher impact
energies than presently available. 相似文献
8.
Walter Bonivento 《Czechoslovak Journal of Physics》1999,49(2):49-60
A large number of measurement related to spin was performed during the last decade at the e + e ? colliders LEP and SLC providing important information on the dynamics of high energy interactions. In this paper three main topics will be covered: the measurements of the electroweak couplings, the study of fragmentation dynamics and the search for physics beyond the Standard Model. 相似文献
9.
In this paper, a surface illuminated InAsSbP/InAs photodetector has been analyzed for operation in 2.0–3.5 m wavelength region. The influence of different dark current components on the resistance-area product (RA) of the photodetector has been estimated theoretically. The results obtained on the basis of the model are found to be in good agreement with the experimental data reported by others. The high value of detectivity of the device at room temperature will make it attractive for use in optical gas sensor. 相似文献
10.
E. P. Grigoriev 《Physics of Atomic Nuclei》2001,64(6):1081-1086
Experimental data on some long bands in N=88–98 deformed nuclei are analyzed on the basis of a method systematizing the energies of levels and inertial parameters and a method employing the analogy between neighboring. Beta bands built on low-lying 0 2 + levels are identified in N=90 isotones, including the 158Er, 160Yb, and 162Hf nuclei. Some of intermediate members of these bands have not been found yet. The systematic properties of 4? bands are presented, and the dynamics of the inertial parameters of these bands in N=88–98 isotones is revealed. The bands are identified in 158Yb, 156Dy, 156Er, 162Yb, and 166Hf. 相似文献
11.
The 0+ ↔ 0− first-forbidden β decay transitions have been investigated for some spherical nuclei. The theoretical framework is based on a proton-neutron
quasiparticle random phase approximation (pnQRPA). The Woods-Saxon potential basis has been used in our calculations. The
transition probabilities have been calculated within the ξ approximation. The relativistic β moment matrix element has been calculated both directly without any assumption and assuming that it is proportional to the
non-relativistic one. 相似文献
12.
The violated supersymmetry property of the pairing interaction between nucleons were restored using the Pyatov method [Pyatov
and Salamov, Nucleonica
22, 127 (1977)]. The eigenvalues and eigenfunctions of the restored Hamiltonian with the separable residual Gamow-Teller effective
interactions in the particle-hole and particle-particle channels were solved within the framework of proton-neutron quasirandom
phase approximation (pnQRPA). The Gamow-Teller resonance energies for 112–124Sb isotopes and the differential cross-sections for Sn(3He, t)Sb reactions at E(3He) = 200 MeV occurring by the excitation of the Gamow-Teller resonance state were calculated. The calculated values were
compared with other calculations and the corresponding experimental data. 相似文献
13.
S.-W. Xu Y.-X. Xie Z.-K. Li X.-D. Wang B. Guo C.-G. Leng C.-F. Wang Y. Yu 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):347-351
The 1/2+ ground state and a 11/2- isomer of very neutron-deficient isotope 143Dy were produced by irradiation of an enriched target of 106Cd with 40Ca and studied by using a helium-jet fast tape-transport system in combination with proton-γ, X-γ and γ-γ coincidence measurements.
A simple ( EC + β+) decay scheme of 143mDy with a half-life of 3.0(3) s and a tentative ( EC + β+) decay scheme of 143gDy with a half-life of 5.6(10) s are proposed. As a by-product, the 347- and 545-keV γ transitions in 138Sm following the β-delayed proton emission of 139Gd decay and the 323-keV γ transition in 139Eu following the β-delayed proton emission of 140Tb decay could be observed for the first time.
Received: 20 August 2002 / Accepted: 28 October 2002 / Published online: 11 February 2003
RID="a"
ID="a"e-mail: xsw@ns.lzb.ac.cn
Communicated by D. Schwalm 相似文献
14.
Using 160GeV muon scattering data collected with the COMPASS experiment at CERN, the exclusive production of ωπ0 via virtual photons was studied. Selective population of a peak around 1250MeV is observed. Possible contributions from spin-parity
1- are searched for, inspecting decay angular correlations. In particular, the orientation of the ω decay plane may allow a
distinction from the 1+
b
1(1235) state. Our observation is compared with indications of a (1250) in annihilation and in γp .
Original article based on material presented at HADRON 2007. 相似文献
15.
W. Szajna M. Zachwieja 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(3):549-555
The high-resolution emission spectrum of the A1
Π–X1Σ+ transition of AlH was observed in the 18 000–25 000 cm-1 spectral region using a conventional spectroscopic
technique. The AlH molecules were excited in an Al hollow-cathode
lamp filled with a mixture of Ne carried gas and a trace amount of
NH3. The emission from the discharge was observed with a plane
grating spectrograph and recorded by a photomultiplier tube. In
total 163 transition wave numbers belonging to six bands (0-0,1
and 1-0,1,2,3) were precisely measured and rotationally
analysed. In the final fit the present data have been combined
with available high-resolution measurements of the
vibration-rotation bands by White et al. [J. Chem. Phys. 99,
8371 (1993)]. This procedure enabled extracting molecular
constants for the A1
Π and X1
Σ+ states of AlH. A very
slight local perturbation has been discovered in the v=1
vibration level of the A1
Π state at J=5. This was probably
caused by the interaction with the a3Π state. 相似文献
16.
17.
Lukáš Pichl 《Czechoslovak Journal of Physics》2005,55(2):167-171
An accurate calculation of the lowest negative electronic state of H
2
-
(fixed nuclei) is reported using the CCSD(T) method and doubly augmented cc-pv5z basis set. Comparison has been made with the reference data by Senekowitsch et al. [Chem. Phys. Lett. 111 (1984) 211]. Owing to larger size of the basisset and inclusion of triple excitations, no vertical shift in this work is necessary to reproduce the asymptotics of H + H -. In addition, the effect of basis-set truncation is estimated, based on the complete-basis-set extrapolation method. The contribution of correlated electron-proton motion to the electron-energy curve for H2
– dynamics is pointed out.Dedicated to Prof. Jií Horáek on the occasion of his 60th birthday. 相似文献
18.
The near-threshold 12C(02+) resonance provides unique possibility for fast helium burning in stars, as predicted by Hoyle to explain the observed abundance
of elements in the Universe. Properties of this resonance are calculated within the framework of the α cluster model whose
two-body and three-body effective potentials are tuned to describe the α-α scattering data, the energies of the 01+ and 02+ states, and the 01+-state rootmean-square radius. The extremely small width of the 02+ state, the 02+ → 01+ monopole transition matrix element, and transition radius are found in remarkable agreement with the experimental data. The
02+-state structure is described as a system of three α particles oscillating between the ground-state-like configuration and
the elongated chain configuration whose probability exceeds 0.9. 相似文献
19.
G. V. Golubkov M. G. Golubkov R. J. Buenker 《Russian Journal of Physical Chemistry B, Focus on Physics》2011,5(6):921-924
The dissociative recombination theory of slow electrons with molecular ions in a strong monochromatic light field is developed.
Classifications of all possible transitions and reaction mechanisms are presented. The potential energy curves of the oxygen
molecule O2** dissociative states and partial cross sections are calculated. 相似文献
20.
Tianyun Chen Ningjiu Zhao Weiping Zhang Xinqiang Wang 《Central European Journal of Physics》2011,9(5):1221-1227
Quasiclassical trajectory method for the title reaction He +H2+ → HeH+ + H was carried out on the potential energy surface which was revised by Aquilanti et al. [Chem. Phys. Lett. 469, 26 (2009)].
The initial vibrational quantum number of reactant was set as v=1, v=2 and v=3. Stereodynamics information of the reaction
was obtained, such as the distributions of product angular momentum P(θ
r
), P(ϕ
r
),p(ϕ
r
, θ
r
) and the two commonly used polarization-dependent differential cross sections (PDDCSs) (2π/σ)(dσ
00/dω
t
) and (2π/σ)(dσ
20/dω
t
), to get the alignment and orientation of product molecules. The results show that the influence of both the collision energy
and vibrational quantum number (v) to the reaction are highly sensitive. 相似文献