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1.
If a new sequential heavy lepton L exists with mass below that of the W boson, it will give rise to the following decay chains: W → LνLwith LeνeνL or LQL. We critically study, and quantify, the possibility of identifying this heavy lepton signal against the various backgrounds in high energy p?p collision. We find that the leptonic decay signal is plagued by serious b?b, W → eν, and W → τν backgrounds, whereas the hadronic decay mode leads to a distinctive signature, after selected cuts are applied. We discuss how the mass of such a lepton may be determined.  相似文献   

2.
The temperature dependence of the field emission flicker noise spectral density functions has been investigated for potassium adsorbed on tungsten (112) planes by a probe hole technique. By integration of the spectral density functions W(?) = Bi??gei the noise power (δn2Δ? for different frequency intervals Δ? is obtained. From the exponential temperature dependence of (δn2Δ? noise power “activation energies” qΔ? are determined. Plots of these energies versus coverage show a similar “oscillating” behaviour as recently found for W(?j) or (δn2Δ?j which indicates phase transitions of the adsorbed potassium submonolayers. The noise activation energies are discussed in terms of existing models and a comparison is made between the experimental q values and surface diffusion energies Ed as determined by conventional methods.  相似文献   

3.
The stability of soliton solutions
ψ = A0sech2νν2Aν20ν+2(x?υt)expiυ24+ν+2Aν0t+υ2(x?υt)
to the nonlinear Schrödinger equation iψt + ψxx + β|ψ|νψ = 0 is investigated for arbitrary positive ν.  相似文献   

4.
Medium resolution infrared grating spectra of gaseous ketene, H2CCO were recorded between 1000 and 400 cm?1, both at instrument temperature (40°C) and with cooling (?40°C). Interferometric Fourier spectra were also measured at ?70°C with resolution 0.22 cm?1 between 450 and 330 cm?1. The K structure of the fundamentals ν5, ν6, ν8, and ν9 was assigned. These fundamentals are coupled by a-axis Coriolis interactions. These couplings were analysed on the symmetric top basis for setting up the perturbation matrix and by utilizing the K-dependent Coriolis shifts of levels. A preliminary analysis of the Coriolis intensity anomalies was also undertaken.Band center values from combination differences are ν50 = 587.30 (27) and ν60 = 528.36 (39) cm?1. Synthetic spectra indicate the band origins of ν8 and ν9 to be close to 977.8 and 439.0 cm?1, respectively. Estimates of Coriolis coupling constants obtained from synthetic spectra are ζ58a = + 0.33 (5), ζ68a = + 0.714 (20), ζ59a = ? 0.774 (20), and ζ69a = ? 0.30 (2). Approximate ratios of unperturbed vibrational transition moments obtained from spectral simulations are M80:±iM50:±iM60:M90 ≈ +2:?9:+10:+0.5.  相似文献   

5.
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 νμγ+X. In the theory of Eliezer and Ross where λLAB ~ 0.8 × 10?19 (m2νμ ? m2νe)/ h?Eν, 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   

6.
The Coriolis interactions between ν1 and ν3, and between ν2 and ν3 in SO2 have been analyzed to obtain the signs of the products ζ3.1c(a?Q3)(b?Q1) and ζ3.2c(a?Q3)(b?Q2). It has been found that both of the signs of these products are positive. Then, relative signs of (?Q1) 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 (?Qi) 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   

7.
A review of polariton modes at interfaces composed of two semiinfinite, homogeneous, and isotropic media is given. Both media are characterized by frequency-dependent dielectric functions ?i(ω), i = 1, 2, and may become “interface-wave-active” in different frequency regions. The conditions for the existance of propagation windows are analyzed and applied to two particular cases: an interface composed of (a) two dielectrics with dielectric functions ?i = ??∞i(ω2 ωLi2ω2ωTi2, where ?t8i are the dielectric constants for very large frequencies and ωTi and ωLi are the transverse and longitudinal phonon frequencies; (b) two conductors with dielectric functions ?i = ?∞i(1 ?ωi2ω2), where ωiare the plasma frequencies. In the first case there exist two propagation windows in the infrared region, while in the second case there is one propagation window in the ultraviolet, visible, or infrared region. The dispersion relations of the modes and their decay distances into the two media are presented, and various damping effects are discussed. The review is concluded with theoretical results on the optical excitation and detection (ATR) of the interface modes.  相似文献   

8.
We consider the general baryon-number violating operators which are produced by dressing the supersymmetric dimension-five operators by gaugino exchanges. We then use chiral dynamics to calculate the widths for the decay modes pK+νd, K0ed+, and nk0νd. The resulting branching ratios are rather sensitive to the precise admixture of the various baryon-number violating operators involved. In particular the decay mode pK+νd is generally dominant in qualitative agreement with previous quark model results.  相似文献   

9.
We present one approach for solving the gauge hierarchy problem in a grand unified supersymmetric theory. Supersymmetry is broken at a scale of order 1012 GeV. Both the grand scale (~1019 GeV) and the weak scale are generated via radiative corrections. The main phenomenological features of the model are: (i) the proton decays into K0μ+andK+νμ and the neutron decays into K0νμ; (ii) the strong GP problem is solved with an invisible axion; (iii) the superpartners of quarks, leptons, gauge and Higgs bosons have masses ~ 50–100 GeV; and (iv) the lightest superpartner is stable.  相似文献   

10.
Charge properties of the hadronic systems from νp and νp scattering in BEBC are studied in the framework of the quark-parto model (QPM). The average charges 〈Qjetν and 〈Qjetν of a quark jet and a d-qua jet, respectively, are determined according to two different methods. The difference 〈Qjetν ? 〈Qjetν is in agreement with e QPM value of 1. Scaling of charge and energy flow in the angular variable λ is demonstrated. The ratios ΔQν/ΔQν of charge flows in νp a νp scattering are in accord with the QPM in both hemispheres.  相似文献   

11.
The magnetic moments of the 12+ isomers in 192, 196, 198, 200, 206Pb and of the 332+ isomer in 205Pb have been measured using the PAD technique. The results for the g-factors are: g(192) = ?0.173(2), g(196) = ?0.1600(15), g(198) = ?0.1552(15), g(200) = ?0.1512(15), g(206) = ?0.1496(18), and g(205) = ?0.148(5). As all states have a rather pure (νi132)?n configuration, the values reflect directly the νi132 orbital. They show a decrease towards the more neutron-deficient isotopes attributed to the reduced core polarisation as a result of decreasing occupation of the i132 neutron shell. The measured systematics are discussed regarding core polarisation, mesonic corrections, and small admixtures of core-excited states to the i132 wave function.  相似文献   

12.
The usual condition for static balance, for two bodies with masses and charges mi and ei (i = 1, 2), is ei=±G12mi. From a post-Newtonian analysis of the two-body problem, an alternate condition for static balance ei=±(Gm1m2)12 has been found. We do not know if this condition is exact beyond the post-Newtonian approximation.  相似文献   

13.
The parameter η̄ of muon decay has been measured in the radiative decay μ+e+νeν?μγ of unpolarized positive muons. The result η??0.083 (68% confidence) or η? = ?0.03±0.10 with ρ fixed at 34 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   

14.
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 sin2θ〉νμ ? 〈sin2θ〉νe = (α)ln(m2μm2e).  相似文献   

15.
We calculate the effective electron-hole interaction Vre in the presence of an exciton gas, which reads in real space:
Vre(r)=?e2r{1+ i=14(?1)iCiexp(?Zira}
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 8πR0?exa03kT?1. (R0, exciton Rydberg, a0 exciyon radius, ?ex exciton density, T temperature).  相似文献   

16.
The resistance of a deuterium plasma generated by a radio frequency discharge near the lower hybrid resonance —power transfer into the plasma between 400W and 1500W — is measured and compared with the theory of a bounded cold plasma. Reasonable agreement is found between measurement and theory only by introducing an effective collision frequency in the range from ν1 = 0.01 ωp up to ν1 = 0.1 ωp. The effective collision frequency introduced in this manner exhibits an almost linear dependence on the power transferred into the plasma (ν1ωp~?P).  相似文献   

17.
The ν events collected in “Gargamelle” exposed at the CERN SPS wide band beam are reanalyzed to search for possible νμνe oscillations. No effect is found and an upper limit of 1.2 eV at 68% c.l. is determined for the mass parameters Δm = (m12 ? m22)12 in the case of maximum neutrino mixing. A limit on the νμντ transition probability is also quoted, but the sensitivity is smaller.  相似文献   

18.
The decay K+ → e+υγ has been investigated. For the structure-dependent part with positive γ-helicity (SD+) the branching ratio Γ(SD+)Γ(Kμ2) = (2.33 ± 0.42) × 10?5 is obtained from 51 ± 3 events observed in the kinematical region Ee ? 235 MeV, Eγ > 48 MeV and θeγ > 140°. For the corresponding part with negative γ-helicity we obtain an upper limit Γ(SD?)/Γ(SD+) < 11 (90% CL) from the sample of electrons with energies 220 MeV ? Ee < 230 MeV and with no γ in the backward direction. This upper limit implies that the ratio of structure-dependent axial vector amplitudes lies outside the region ?1.8 < aKυK < ?0.54.For the decay K+e+ννν the limit Γ(K+e+ννν)/Γ(Ke2) < 3.8 90% confidence level) was found.  相似文献   

19.
In a class of supersymmetric GUTs with a coloured Higgs sector of an intermediate mass, we study nucleon decay and the generation of baryon assymmetry. We find that: (a) a non-vanishing baryon asymmetry can be generated by the decay of coloured Higgs bosons and Higgs fermions into quarks and squarks; (b) nucleons decay at a rate 10?31 yr?1 preferably to μ+K0, νμK+ while decay involving dimension-five operators is kinematically excluded.  相似文献   

20.
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