共查询到20条相似文献,搜索用时 15 毫秒
1.
We discuss how semi-leptonic decays of charmed baryons can be used to discriminate between different forms of the charm-changing weak current. Some information can be obtained from the energy and invariant mass distributions of the decay products. More sensitive tests can be made using the polarizations of strange baryons such as Λ, Σ or Ξ in the final state. In principle V±A, pure V and pure A coupling types can all be distinguished. Tests using decays of charmed baryons, such as , are more sensitive than those using decays of baryons, such as . 相似文献
2.
A.C.David Wright 《Physics letters. [Part B]》1977,71(2):425-428
Cross sections for charmed baryon pair production near threshold in e+e? annihilation are calculated using pole-dominated form factors modified to take intoccount continuum effects. When the C0+0? production cross section is normalized with the help of data for it is found that the total charmed baryon production cross reaches a peak value of approximately 2.7 nb at √s = 5 GeV. 相似文献
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4.
Yu. Oročko 《Reports on Mathematical Physics》1979,15(2):163-172
Let ,m? 1.Consider the operatorT0 = ?Δ+q with domain consisting of all bounded measurable functions , having bounded support, for which the distribution ?Δu+qu belongs to . The main result of the paper is essential self-adjointness of . The proof is independent of a method due to Kato who recently established the self-adjointness of a maximal Schrödinger operator corresponding to such potential. 相似文献
5.
The rotational spectrum of methylene cyanide has been measured up to J = 62 and a total of 82 b-type transitions have been obtained. These data have been analyzed with a semirigid rotor Hamiltonian to give accurate rotational and centrifugal distortion constants. The rotational constants are (in MHz) = 20882.7537 ≠ 0.017, = 2942.3003. ≠ 0.0031, = 2616.7225 ≠ 0.0031 The quartic centrifugal distortion constants are (in MHz) The uncertainties are twice the standard deviations in the constants obtained from the least squares analysis, and represent approximately 95% confidence limits. 相似文献
6.
From a study of (p,t) reactions on 31P and 30Si it is suggested that in 29P the states with and , the pair , , and the pair , are related by weak coupling of a s proton with the states 01+, 02+, 21+ and 41+ respectively of 28Si. Completely atypical L = 2 angular distributions have been obtained for the and states in 29P and it is suggested that this is due to contribution by two-step processes. 相似文献
7.
Potential energy functions for the ground states of the linear triatomics HCN, HNC () and HCP () were derived, by minimizing the difference between the observed vibrational frequencies and those calculated from the potentials by a variational method. Good agreement is obtained between the observed and calculated spectra for HCN and HNC. For the HCP system, a secondary minimum is predicted to lie on the ground-state surface (linear HPC) having dimensions , , and an energy of 3.8 eV above the HCP () minimum. 相似文献
8.
G. Sobotta 《Solid State Communications》1982,43(11):875-877
A field theoretical model is proposed to describe the critical behaviour of a strongly inhomogeneous spin system with a position dependent concentration of magnetic atoms C(R) and magnetisation M(R). Assuming a finite number of Fouriermodes ,..., , to express C(R), the quenched randomness requires to interpret {} on a set of invariant or marginal lengths. As consequence, M(R) can be described by n Fourier-modes MQv, where . For short range spin-spin interaction, we find for strong inhomogeneity, i.e. large n, the critical exponent between those of the related homogeneous system and those of the spherical model. 相似文献
9.
Radha Balakrishnan 《Physica D: Nonlinear Phenomena》1985,16(3):405-413
Using an extended AKNS-ZS formalism developed in earlier work, we present a systematic inverse spectral transform analysis and solution of the generalized nonlinear Schrödinger equation which arises in certain physical problems involving inhomogeneous interactions (or media). Physically interesting forms of the inhomogeneity function f(x) are discussed, that support localized solutions and permit non-dissipative tunneling of lump-like solutions through the inhomogeneity. 相似文献
10.
Hyperfine structure of the (0, 0, 1) - (1, 0, 1) transition of methanol has been investigated by beam absorption and of the (J, 1, 3?) → (J, 1, 3+) transitions for J = 2, 3, and 6 by beam-maser spectroscopy. The best-fit results for the spin-rotation and spin-spin coupling constants and , respectively, are in kHz1: , , , , , and (. 相似文献
11.
The self-diffusion coefficients of 14C in NbCx single crystals have been measured as a function of composition in the temperature range 1900–2315 K, and can be represented by the expressions The lower values of the activation energy and the pre-exponential term in NbC0.766 are attributed to a change in the path of C mass transport from that of an octahedral-tetrahedral-octahedral mechanism in NbC0.868 and NbC0.834 involving a C-metal divacancy mechanism. The effect of lattice geometry and the electronic charge distribution on the diffusion mechanism is also discussed. 相似文献
12.
We calculate the effective electron-hole interaction Vre in the presence of an exciton gas, which reads in real space: The parameters Ci and Zi are given explicitly for GaAs. For this material, we show the binding energy of the exciton is weakly modified so long as . (R0, exciton Rydberg, a0 exciyon radius, ?ex exciton density, T temperature). 相似文献
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A red-degraded band head, normally badly overlapped by the gamma system, , of zirconium oxide, appears in emission spectra of zirconium arcs and in absorption spectra of S-type stars and of frozen rare gas matrices containing zirconium. The emission band has been examined at high-resolution with the aid of separated zirconium isotopes. Identification of the band as 0-0 of a system of zirconium oxide is confirmed by rotational analysis where the following constants (cm?1) are obtained for 90Zr16O: The Λ-type doubling in the 1Π state and the question of whether or is the true ground state of ZrO are discussed. 相似文献
15.
Revised and more complete vibrational assignments are made for the 3540-Å band system of malonaldehyde. The tunneling splitting is found to be 19 ± 11 cm?1 for the state and this represents a 7-cm?1 decrease relative to the ground electronic state. The tunneling splitting and the Franck-Condon envelope of intensities in the 185-cm?1 upper-state progression suggest that the state is significantly less tightly hydrogen-bonded than the ground 1A1 state. 相似文献
16.
Measurements have been carried out of the elastic constants of SrO in the virgin undoped state and of the changes produced in them by equilibrium doping with oxygen at ? 1200°C and oxygen partial pressure of 0.95 atm. The method used was Papadakis' pulse-echo overlap technique in conjunction with thermogravimetric analysis (T.G.A.) to determine mass and density changes due to oxygen doping.The values obtained for C11, C12 and C44 of the virgin crystal at 23°C are ;;.(These values are in very good agreement with those of Son and Bartels [2].)Values for and were found to be ?1.74% and ?0.86% respectively. Accurate valu could not be obtained because of sample size limitations after quenching. However, C12 was shown to definitely increase due to doping.Analysis of the results indicate that the elastic modulus changes can only be attributed to the formation of cation vacancies during doping. Analysis of the T.G.A. behavior indicates that this cation vacancy formation is probably associated with the presence of various tripositive cation and uninegative anion species depending upon the impurity concentrations of the sample. This implied impurity-controlled cation vacancy concentration is consistent with the earlier observed extrinsic nature of cation diffusion in SrO at 1200°C. 相似文献
17.
Line positions and molecular constants for the 0-0, 1-0, 2-0, 0-1, 2-1, 3-1, 0-2, 1-2, and 4-2 bands of the C2 Phillips system () are reported. Among them, five bands have not been reported previously. Rotational perturbations have been observed in the previously unobserved v = 1 level of the state. This state is perturbed by the state which was discovered by Ballik and Ramsay. These observations provide new information regarding the perturbing state. In particular, the minimum of the potential energy for the state has been found to be at 9227.4 cm?1 instead of 13 310 cm?1, which was the previous Te value for this electronic state. 相似文献
18.
The emission spectrum of the He2 molecule has been rephotographed in the ~4000–~5700 Å region and the , , and transitions analyzed. The 4dδj3Δu, 4dπj3Πu, and states have been characterized through v = 2 and the 4dδJ1Δu, 4dπJ1Πu, , and states for v = 0. The term levels for these perturbed and l-uncoupled states have been confirmed (a) by analyses of bands with common levels from Δv = 0, ±1 sequences and (b) by analyses of the transitions between the above states from 4d and 4s and the and states associated with 3pσ. Molecular constants are reported which have been partially corrected for the effects of l-uncoupling and the homogeneous perturbations between the state pairs J, H and j, h. 相似文献
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Carl-G. Källman 《Physics letters. [Part B]》1979,85(4):392-394
Vacuum fluctuation effects in QCD due to instantons are considered in dense neutron star matter. In the density region of interest to neutron star cores we find a density dependence , in contrast to a result by Shuryak, . 相似文献