共查询到20条相似文献,搜索用时 46 毫秒
1.
Virgil E. Barnes 《Physics letters. [Part B]》1976,65(2):174-176
The nonobservation of photon-induced e+e? pairs pointing in the neutrino beam direction in large bubble chambers would allow one to set an upper limit on the product mνμλCM for muon-type neutrinos, where mνμ is the mass and λCM is the intrinsic partial decay width in sec?1 for νμ→γ+X. In the theory of Eliezer and Ross where , this implies an upper limit on mνμ considerably smaller than the present upper limit, and a large lower limit on the lifetime τνμ. 相似文献
2.
P. Fayet 《Nuclear Physics B》1974,78(1):14-28
We present a unified gauge theory of weak and electromagnetic interactions in which parity is spontaneously broken together with gauge invariance, by the Higgs mechanism. The gauge group is SU(2) × U(1), and a heavy neutrino is associated with every charged lepton. After the breaking of the original parity-conserving theory, both a purely vector electromagnetic current and the usual V-A charged currents are obtained. Z is coupled to a vector electron current, and the model predicts equal cross sections. Extension to hadrons is made by introducing three charmed quarks p′, n′ and λ′ of the same charges as p, n and λ. All the experimental results , νμ and hadron scatterings) are compatible with a value of sin2θW of order 0.4. 相似文献
3.
The parameter η̄ of muon decay has been measured in the radiative decay of unpolarized positive muons. The result (68% confidence) or with ρ fixed at yields an improvement of the previous value by more than a factor of two. An analysis of all data on muon decay that are presently available slightly improves the constraints on the weak coupling constants to: gs?0.29gv, gp?0.27gv, gT?0.23gv and 0.92gv?gA?1.2gv 相似文献
4.
D. Allasia C. Angelini A. Baldini S. Barlag L. Bertanza A. Bigi V. Bisi F. Bobisut T. Bolognese R. Bonarelli E. Calimani R. Casali P. Capiluppi S. Ciampolillo J. Derkaoui E. De Wolf M.L. Faccini-Turleur R. Wigmans 《Nuclear Physics B》1984,239(2):301-310
The total νμ and nucleon charged-current cross sections have been measured in BEBC filled with deuterium and exposed to the wide-band neutrino and antineutrino beams at the CERN-SPS. Assuming a linear energy dependence for the cross sections, σ = aE(?ν, we obtained the coefficients , where the quoted error is mainly systematic. The ratio of the cross sections is .We also determined the ratio of the charged-current cross section for neutrino interactions on neutrons and protons R = σνn/σνp = 2.10 ± 0.08 (statistical) ±0.22 (sysetmatic). The dependence of R on the variables x, y and Eν is discussed. 相似文献
5.
Yasuki Endo Shuji Saito Eizi Hirota Toshio Chikaraishi 《Journal of Molecular Spectroscopy》1979,77(2):222-234
Microwave spectra of SF2 in the first excited states of the three normal modes were observed and analyzed. A comparison of the observed inertia defects in the ν1 and ν3 states with those calculated by omitting the contributions of the Coriolis interaction between the two modes led to a vibrational frequency differences of 25.72 ± 0.33 cm?1, with ν1 being definitely higher. The inertia defect in the ground state and our measured values for the inertia defect in the ν2 state and for the difference were combined with the centrifugal distortion constants of Kirchhoff et al. [J. Mol. Spectrosc.48, 157–164 (1973)] to improve the harmonic force field. The interaction constant between the two SF stretching coordinates was determined precisely. The third-order and the cubic anharmonic potential constants were calculated from the observed vibration-rotation constants. The equilibrium structure was determined to be and θe(FSF) = 98.048 ± 0.013°. 相似文献
6.
We propose to explain two observed anomalies that suggest extension of the minimal gauge scheme, the eμ production in the e+e? reaction and the anomalous y-distribution in reactions, as being caused by a single object, a heavy muon. With more accurate neutrino data this explanation can readily be distinguished from that of a new quark production. 相似文献
7.
A. Possoz Ph. Deschepper L. Grenacs P. Lebrun J. Lehmann L. Palffy A. De Moura Gonçalves C. Samour V.L. Telegdi 《Physics letters. [Part B]》1977,70(2):265-268
The helicity, h?, of μ? in π-decay has been determined as positive (h??+0.90) from the average polarization, Pav≡〈JB·sμ〉, of 12B produced in the reaction. We obtain also dynamical information on μ-capture: (i) the weak magnetism form factor, μ=4.5±1.1, and (ii) the sum of the induced pseudoscalar (gp) and the 2nd class induced tensor (gT) couplings versus gA, (. The latter result, adopting the “canonical” value of , leads to which is compatible with zero and in strong contradiction with the value ?—6 recently advocated by Kubodera, Delorme and Rho. 相似文献
8.
Nicola Cabibbo 《Physics letters. [Part B]》1978,72(3):333-335
We discuss the possibility of CP or T violation in neutrino oscillation. CP requires νμ ? νe and oscillations to be equal. Time reversal invariance requires the oscillation probability to be an even function of time. Both conditions can be violated, even drastically, if more than two neutrinos exist. 相似文献
9.
D. Bertrand G. Bertrand-Coremans R. Blaes F.W. Bullock M. Dewit B. Escoubes E. Fett A. Haatuft A. Halsteinslid T.W. Jones J.G. Morfin K. Myklebost J.M. Olsen P. Petitjean M. Pohl F. Rahimi P.N. Ratoff J. Sacton L.C. Welch 《Physics letters. [Part B]》1979,84(3):354-356
Candidates for the purely leptonic process have been searched for in the bubble chamber Gargamelle exposed to the CERN-SPS antineutrino wide-band beam. No single e?, of energy greater than 1 GeV, was found in a total of 230 000 pictures, corresponding to 7400 charged current events. This leads to an upper limit for the observed cross section of cm2 (90% C.L.). Interpretation of this value in terms of the standard W Weinberg-Salam model yields an upper limit to the mixing parameter sin2θW < 0.39 at 90% C.L. 相似文献
10.
A weak emission spectrum of I2 near 2770 Å is reanalyzed and found to to minate on the A(1u3Π) state. The assigned bands span v″ levels 5–19 and v′ levels 0–8. The new assignment is corroborated by isotope shifts, band profile simulations, and Franck-Condon calculations. The excited state is an ion-pair state, probably the 1g state which tends toward . In combination with other results for the A state, the analysis yields the following spectroscopic constants: T″e = 10 907 cm?1, ″e = 1640 cm?1, ω″e = 95 cm?1, ; T′e = 47 559.1 cm?1, ω′e = 106.60 cm?1, . 相似文献
11.
J.P. Berge D. Bogert R. Hanft D. Hamilton G. Harigel J.A. Malko G.I. Moffatt F.A. Nezrick J. Wolfson V.V. Ammosov A.G. Denisov P.F. Ermolov G.S. Gapienko V.A. Gapienko V.I. Klukhin V.I. Koreshev P.V. Pitukhin V.I. Sirotenko E. Wang 《Physics letters. [Part B]》1979,84(3):357-359
We have searched for candidates for the weak neutral leptonic current reaction in the Fermilab 15 ft bubble chamber filled with a heavy neon-hydrogen mix. Based on zero observed events of this type we find the 90% confidence level upper limit for the rate for this reaction relative to the total antineutrino charged current rate to be 3.9 × 10?4 and, in the Weinberg-Salam model, sin2θW ? 0.37. 相似文献
12.
The Raman active fundamentals ν1(A1g), ν2(Eg), ν5(F2g), and the overtone 2ν6 of SF6 have been investigated with a higher resolution and the band origins were estimated to be: ν1 = 774.53 cm?1, ν2 = 643.35 cm?1, ν5 = 523.5 cm?1, and 2ν6 = 693.8 cm?1. Raman and infrared data have been combined for estimation of several anharmonicity constants. The ν6 fundamental frequency is calculated as 347.0 cm?1. From the analysis of the ν2 Raman band, the following rotational constants of both the ground and upper states have been calculated: ; . 相似文献
13.
The Coriolis resonance between ν4 and ν7 in CH3CN and between ν1 and ν5, ν3 and ν6, and ν4 and ν7 in CD3CN has been analyzed, applying the technique developed by DiLauro and Mills, to obtain the signs of [] and the ratio of to for the interacting pairs in CD3CN. For (ν4, ν7) in both CH3CN and CD3CN, the sign of [] is found to be negative as it is also for (ν1, ν5) in CD3CN. For (ν3, ν6) the sign of this interaction term is found to be positive. For a given definition of normal coordinates the signs of these interaction terms give the relative signs of and ; our study also gives approximate values for the corresponding ratio [] 相似文献
14.
In the presence of right-handed currents including , it is emphasized that the dominant parity-violating (-conserving) Hamiltonian for nonleptonic decays of charmed hadrons transforms like of SU(4), and leads to distinctive results especially in D+ → KSπ+, F+ → μ+νμ and D0 → K?e+νe, etc. 相似文献
15.
Yoav Achiman 《Physics letters. [Part B]》1977,70(2):187-191
A left-right symmetric SUL(3) × SUR(3) gauge model with leptons in the () representation is presented. The SUIL(2)×U(1) subgroup is practically the WS + GIM model for , with additional currents involving heavy leptons. μ→eγ is naturally suppressed and a new kind of oscillations is possible. τ and 3μ events can be related to one leptonic triplet. The model is naturally imbedded in exceptional groups. 相似文献
16.
O. Dumbrajs R. Koch H. Pilkuhn G.C. Oades H. Behrens J.J. de Swart P. Kroll 《Nuclear Physics B》1983,216(2):277-335
The electron capture decay occurs with a record low energy release, Q ~ 2.6 keV. The daughter DyH atom has an electron hole, H, and predominantly decays by electron ejection DyH→DyH1H2+e?. We investigate the neutrino mass sensitivity of the electron spectrum in the overall process Ho→DyH1H2+e?+νe. In this spectrum, the fraction of events sensitive to a fixed non-zero neutrino mass in one to two orders of magnitude smaller than in the standard case of tritium β decay. But the electron energies in 163Ho decay are considerably smaller than in 3H decay (Q ~ 18 keV). This suggests experiments whose energy resolution could be much better than that of the magnetic spectrometers conventionally used in the tritium case. 相似文献
17.
We distinguish electron and positron tracks from νe and charged-current interactions in a large bubble chamber f ed with a neon-hydrogen mixture. No evidence is seen for an excess of interactions from primary sources secondary oscillations. Upper limits on oscillation parameters, majoron sion and lepton-number violating π and K decays are presented. 相似文献
18.
A modified Kuti-Weisskopf model which satisfies the Feynman threshold constraints is considered further. Detailed predictions for the sum of neutrino and anti-neutrino differential cross sections on nucleon (which can be readily compared with forthcoming NAL data), the shapes of the structure functions and the ratio , and spin-dependence of inelastic electron-nucleon scattering versus scaling variable x are delineated. We also compare in some detail the general features of our model with the “model independent” approach of Feynman for quark parton theory. 相似文献
19.
We examine the effects of higher-order corrections on the universality between νμ and νe in the Weinberg-Salam model. The leading correction to neutral current amplitudes is an apparent difference in the values of sin2θ as measured by νμ and νe beams. The difference is . 相似文献
20.
Taisuke Nakanaga Shigeo Kondo Shinnosuke Saëki 《Journal of Molecular Spectroscopy》1980,81(2):413-423
The Coriolis interactions between ν1 and ν3, and between ν2 and ν3 in SO2 have been analyzed to obtain the signs of the products and . It has been found that both of the signs of these products are positive. Then, relative signs of () have been determined using the calculated values of the Coriolis zeta constants for the present definition of the normal coordinates. The obtained sign combination of () is ±(+?+), which agrees with the one predicted by the molecular orbital calculations. Using the sign combination (+?+), the polar tensors of S and O atoms were also calculated. 相似文献