共查询到20条相似文献,搜索用时 46 毫秒
1.
A. Berglund T. Buran P.J. Carlson C.J.S. Damerell I. Endo A.R. Gillman V. Gracco R.J. Homer M.J. Hotchkiss A. Lundby M. Macri B.N. Ratcliff A. Santroni T. Tso F. Wickens J.A. Wilson 《Physics letters. [Part B]》1975,57(1):100-104
For the first time, the reactions π+p→K+∑+ and K?p→π?∑+ have been studied in the same apparatus. This has been done at an adequately high momentum (10.1 GeV/c) to allow a check of the prediction of exchange degeneracy, that the differential cross sections should be converging at high energy. We have measured the cross section for momentum transfers t between tmin and t = ?0.3 (GeV/c)2. We find that for both reactions the differential cross section shows an exponential fall, with no deviations right in to t =tmin (where some other experiments have shown a dip in the cross section). Furthermore, we find the magnitude of the differential cross sections to be closely similar at t = 0, with a ratio However, the slope for the positive reaction is about 19% steeper than that for the negative reaction. 相似文献
2.
D. Dekkers J.P. Guillaud V. Lepeltier M.N. Minard H. Pessard T.R. Willitts M. Yvert 《Nuclear Physics B》1977,131(1):72-79
Measurement of the exotic exchange reaction π?p → K+Σ? has been performed at 5 and 8 GeV, in the ?0.015 to ?0.13 and ?0.009 to ?0.15 (GeV/c)2 range of t repectively. We give the value near t = 0 of the differential cross section at 5 GeV, 21?21+76 nb/(GeV/c)2, and an upper limit (< 37 nb/GeV/c)2) at 8 GeV. As a check the measured differential cross section is given at both energies for the reaction π+p → K+Σ+ in the same range of t. 相似文献
3.
The hard photon emission in e+e? → μ+μ?γ is investigated to order α3. Formulas for a number of distributions are obtained, when neglecting terms of order (me/?)2 and (mμ/?)2. Both charge-even and charge-odd contributions are calculated. The total contribution to the charge asymmetry parameter does not exceed 5% for the c.m.s. energy 2? = 3 GeV. 相似文献
4.
We have analyzed the D^0→π^+π^- decay with α_s corrections in quantum chromodynamic (QCD) factorization and with the soft-gluon corrections in the light cone QCD sum rules. The soft-gluon effects are firstly calculated in the decay channel. The results show that once the factorization contributions, the α_s corrections, and the soft-gluon effects are all considered, we can satisfactorily explain the experimental data in the decay channel. 相似文献
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6.
H. -J. Behrend L. Criegee J. H. Field G. Franke H. Jung J. Meyer O. Podobrin V. Schr?der G. G. Winter P. J. Bussey et al. 《Zeitschrift fur Physik C Particles and Fields》1991,49(1):43-48
We have studied the 0 production rate in the reaction 3+3– in the energy range 1.6W
7.5 GeV with the CELLO detector at PETRA. Our analysis points to a substantial yield of 00+– events in particular atW
>4.0 GeV. We give cross sections for the 02+2– and 00+– final states and calculate upper limits for the reaction 00 (1700) 00+–.Now at CERN 相似文献
7.
用BESⅠ的7.8×106J/ψ数据更为精确地测定了J/ψ→π03(π+π-)和J/ψ→ω2(π+π-)的分支比(Br(J/ψ→π03(π+π-))=(2.52±0.06±0.43)%,Br(J/ψ→π03(π+π-))=(1.31±0.09±0.21)%.同时对4π不变质量谱和ωππ不变质量谱进行研究分析,试图观察是否存在有兴趣的信号. 相似文献
8.
E. P. Shabalin 《Physics of Atomic Nuclei》2010,73(11):1908-1915
The unitarization of the amplitude for the decay process K
10 → π+π− and allowance for the rescattering of final-state pions in the decay process K
+ → π+π+π− make it possible to evaluate, by using the parameters extracted from data on K → 2π decays, the K
+ → π+π+π− decay width. The result agrees with the experimental width value at a level of a few percent. Allowance for corrections for
higher order terms of the momentum expansion of the amplitude for the decay process K
+ → π+π+π− leads to the slope-parameter value of g
++−th = 0.2182, which agrees with its experimental counterpart, g
++−exp = 0.2154 ± 0.0035. 相似文献
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11.
利用色散关系研究了弱电流不守恒情况下的π-→π0+e+ν衰变过程。在对π—π散射相移作了一些假定后,证明了π、π中间态的贡献很小。在N、N中间态项中出现的N、N湮灭矩阵元用Chew-Ball理论及湮灭实验估计,同时出现的核子弱作用形状因子又用色散关系计算,证明了N、N中间态对它的贡献很小,计算了π、π中间态对它的贡献。根据现有N、N湮灭实验估计,π-→π0+e+ν过程的衰变几率<6×10-4秒-1。 相似文献
12.
P.F. Bernath R.W. Field B. Pinchemel Y. Lefebvre J. Schamps 《Journal of Molecular Spectroscopy》1981,88(1):175-193
Laser excitation spectra have been recorded for Ca79Br and Ca81Br in the spectral region 600–630 nm. The use of a 1-m monochromator as a narrow band pass filter (1–2 cm?1) has allowed rotational analysis of the 0-0, 1-1, and 2-2 bands of the B2Σ+ - X2Σ+ transition and the 0-0 and 1-1 bands of the A2Π - X2Σ+ transition. A few additional lines of the 0-1, 1-2, 1-0, and 2-1 bands of the B-X system were used to obtain band origins for vibrational analysis. The main constants for Ca79Br are (in cm?1):
0 | 15 958.41 (10) | 16 383.137 (6) | |
285.732 (9) | 288.56 (20) | 285.747 (9) | |
0.840 (4) | — | 0.954 (4) | |
0.094466141 (30) | 0.0957343 (20) | 0.0965151 (20) | |
0.000403551 (40) | 0.0004327 (20) | 0.0004483 (15) | |
(spin-rot.) | 0.00301484 (50) | — | 0.068767 (79) |
— | ?0.066834 (64) | — | |
— | 59.175 (1) | — |
0 | 15 624.67(5) | 15 700.52(12) | |
238.7496(33) | 241.19(7) | 242.63(17) | |
0.62789(64) | 0.53(5) (Pekeris) | 1.17(12) (Pekeris) | |
0.0693254(84) | 0.070460(14) | 0.071572(22) | |
2.640(35) | 2.15(10) | 3.95(2) | |
— | 45.8968(52) | — | |
2.8286(2) | 2.8057(3) | 2.7839(4) |
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