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1.
A few neutrino-induced tetramuon events have recently been reported by two experimental groups with a production rate of 10–6 for( + +)/ ( ). However, the rate for such events is not yet determined theoretically. In the present paper, we report on a detailed calculation of the rate in the framework of a heavy quark cascade mechanism, using the QCD-improved parton distribution functions parametrized by Buras and Gaemers, which have successfully fitted various experimental data. Our calculation for( + +)/ () accords well with the CDHS and FHPRW rate. The computed rate is also in accord with that obtained via the radiative charm model calculation, whereby the normal charm dimuon production is accompanied by a radiative + pair.  相似文献   

2.
Using a grating-tuned CO2-TEA laser to pump CH3OH in a metallic-wave-guide resonator, submillimeter laser emissions have been produced by pumping with 36 lines in the 9.4m CO2 band and with 23 lines in the 10.6m band. Several dozen new SMM laser lines were observed. Wavelengths accurate to within 0.1% are given for 12 previously unmeasured lines between 34m and 225m.  相似文献   

3.
A compact CO2–NH3 FIR laser system where an NH3 laser cavity was inserted in pump, three mirror CO2 laser cavity was designed. The total length of this system was about 1.8 m. Output energy of about 1 mJ (10 KW pea power) was obtained at the 152 m and 90 m lines in NH3. Power conversion efficiency of 1.7 percent was obtained at the 90 m line.  相似文献   

4.
Thirty-nine new submillimetre laser lines in CH2F2 and twelve in CD2Cl2 have been obtained in a Fabry-Perot FIR resonator by optically pumping with a CW12C18O2 laser. The wavelength range obtained for CH2F2 is 126m to 1091m and for CD2Cl2 212m to 774m. The wavelength measurements are accurate to within 5.10–3. The relative polarisations of the pump laser and the FIR laser output were also determined. Tentative assignments of the IR and FIR transitions were made using existing microwave data.  相似文献   

5.
Direct measurements of small signal and saturated gain in cw laser pumped CH3OD are reported for three lasing transitions of 57 m, 82 m and 103 m. The 57 m transition has a measured gain of 0.6/m, the strongest gain in methanol reported so far. Moreover small gain saturation of this line makes it to be one of the strongest known cw FIR laser lines.  相似文献   

6.
The tuning characteristics of a uv preionized 20-atmospheres gas discharge CO2 laser with a novel and simple preionization scheme have been investigated. Continuous tunability in all branches of the 9.4 m and 10.4 m band with a total tuning range of more than 60 cm–1 without frequency pulling is demonstrated. Additionally, a study of the laser pulse behaviour was performed.  相似文献   

7.
A 16-m CF4 laser oscillator has operated at 1 kHz in a cooled static cell. Pump energies required from the low pressure, Q-switched, cw discharge CO2 laser were as low as 60 J. The laser cavity employed a multiple-pass off-axis path resonator in a ring configuration. CF4 laser power at 615 cm–1 and a 1-kHz repetition rate exceeded 300 W.  相似文献   

8.
An unified miniature optically pumped NH3 submillimeter wave laser (OPSMMWL), including a mini TEA-CO2 pump laser, was developed. It lased successfully with coherent emission at 67.2m, 90.4m and 151.5m. The optimum operation of the unified mini-OPSMMWL was studied experimentally and the relations among SMMW laser output power, operating gas pressure, length and coupling condition of the cavity were measured. It has been found that buffer gas N2 has significant effect on 67.2m and 151.5m emissions and very wide band SMMW laser emission was a common feature of the mini-OPSMMW cavity laser.  相似文献   

9.
Fifty-five new submillimeter laser lines from optically pumped CD2Cl2, have been obtained in a FIR metallic waveguide resonator. Twenty-seven lines, ranging from 184 m to 1387 m, and twenty-eight lines, from 219 m to 888 m, have been observed when using CW CO2 laser and CW N2O laser optical pumping, respectively. The accuracy of wavelength measurements are of the order of 3.10–3.  相似文献   

10.
We give a simplified construction of twist eating configurations, based on a theorem due to Frobenius. These configurations are defined through the equation:U U U + U + =exp(2in /N) withU SU(N), =1 tod andn an antisymmetric matrix with integer entries. In the (Twisted)-Eguchi-Kawai model they yield extrema some of which survive forN. Comparison is made with the Monte Carlo data of the internal energy in the small coupling region.  相似文献   

11.
Respectively, 41 and 36 new cw far-infrared lasing lines have been observed using a waveguide resonator in CH3OD and CD3OD pumped by a low-pressure CO2 laser emitting in the 9.4, 10.4 m regular bands and in the 10.8 m hot band. The wavelength range was 46.6 m–1.67 mm in CH3OD and 53.6 m–1 mm in CD3OD.  相似文献   

12.
Rates of particle-emitting decay of the resonant state of the muonic molecular ion (dHe) J=1 lying below the (d)1s-He threshold can decay to the d-He scattering state. The resonant state is estimated by scattering calculations with the non-adiabatic coupled-rearrangement-channel method. Strong isotope dependence of the decay rates of (d3He) J=1 and (d4He) J=1 is predicted, though the calculated radiative decay rates of the states are almost the same. In (d3He) J=1, the particle decay width is three times larger than the radiative decay width, while the two types of decay widths are almost the same in (d4He) J=1. This results in a strong hindrance of the branching ratio of the radiative decay of (d3He) J=1 compared with the case of (d4He) J=1. This is consistent with a recent observation of the radiative decay of the two molecular states.  相似文献   

13.
The isotopomer of methanol, CD3OD, was optically pumped by a cw CO2 laser resulting in 53 new far-infrared (FIR) laser lines. The wavelengths are in the range 42.9 m to 189.9 m with the majority below 100 m. Ten different CO2 lines were used for the first time to pump CD3OD yielding new FIR laser lines. Some of the CO2 pump lines belong to the hot-bands and sequence-bands of CO2 in the 10 m region. The frequency was measured for 40 FIR laser lines in the range 1.5 THz to 6.9 THz, 32 of which were new laser lines.  相似文献   

14.
We report for the first time wavelength, relative polarization, and frequency measurements for 47 new cw FIR laser lines in the wavelength region from 120 to 1714 m, all obtained by optically pumping CD2F2 with a CO2 laser. Relative output powers were also measured. For comparison, the 189.8 m line pumped by RI(34) is nearly five times as efficient as the 118.8 m methyl alcohol line.Contribution of the U.S. Government, not subject to copyright.  相似文献   

15.
The central limit theorem of Cushen and Hudson is reformulated on the algebra of the CCR. Namely, for a gauge invariant state , the weighted convolutions n of the central limit tend to the quasi-free reduction Q of pointwise. It is proved that if the initial relative entropy S(, Q ) is finite, then S( n , Q ) goes to 0 and so n Q 0. No restriction on the dimension of the test function space is made.  相似文献   

16.
The paramagnetic state (+e) in Si and Te was observed in a longitudinal magnetic field. The mean lifetimes of these states were obtained: Si = 1.45(3) s, Te = 12.5(8) s at 290 K, Te = 12(2) s at 250 K.  相似文献   

17.
The far infrared response of granular thin-film Bi2Sr2CaCu2O8 superconductor has been investigated using long (5 s) but sharply truncated free electron laser pulses in the frequency range between 50 cm–1 and 125 cm–1. Under constant current bias, a fast response and a slow bolometric signal component could be identified in this energy range, which is below the BCS energy gap ( 200 cm–1). Measurements of the power dependences of the signal voltages showed that both the fast and the thermal responses are consistent with the predictions of the resistively shunted Josephson junction model.  相似文献   

18.
In a systematic study of the transfer process to sulphur dioxide, in seven different H2 + SO2 gas mixtures, the time spectra of the muonic sulphur X-rays yield muon transfer rates to the SO2 molecule, deduced from the lifetimes of the p atoms, which agree all well with each other. The muonic oxygen time spectra show an additional structure as if p atoms of another kind were present. Reduced transfer ratesO are reproducible if one uses the model of ephemeral p atoms. The intensity ratios between the different kinds of p atoms are also discussed in the framework of this model and the one of black and white p atoms.  相似文献   

19.
By using the [General Relativity + additional matter fields] formulation (which depends on a redefined metrich ) of metric theories of gravitation, the study of singularities characterized by incomplete nonspacelike geodesics is simplified, but may be used only if (at least) the non-spacelike geodesics of the original metricg are conserved under the transformation betweeng and the new metrich . In order that every class of geodesies of a diagonal Bianchi I metric correspond to the same class of geodesies of a diagonal metrich , it is necessary that the transformation between these two metrics be a constant (positive) conformal transformation. We analyse the implications of the previous results for the singularitiesg when the latter is a solution of theories with a quadratic or polynomial Lagrangian.  相似文献   

20.
Low temperature nuclear orientation experiments down to 2 mK on147GdFe,149GdFe,149GdGd and153GdGd have yielded the magnetic hyperfine interaction strength. Bhf as 31.0(1.6) NT, 28.3(2.0) NT, 33.8(4.7) NT and 13.3(2.1) NT respectively. From these values the respective ground state magnetic moments ¦¦ of147Gd,149Gd and159Gd were deduced as 1.12(20) N, 1.01(16) N and 0.40(8) N.  相似文献   

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