共查询到19条相似文献,搜索用时 62 毫秒
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用程函近似分析在高能核碰撞中次级作用对K+/π+比的影响.计算表明,在K+/π+比中次级碰撞效应是重要的. 相似文献
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K+-Na+二次离子交换制作玻璃波导 总被引:4,自引:4,他引:0
通过数值计算模拟了K+Na+二次扩散玻璃波导的折射率轮廓,阐述了利用K+Na+二次离子交换的方法,在BK7玻璃上制作波导的过程,分析了极化率不同的扩散离子对的选择对波导有效折射率变化的影响,以及扩散平衡时体积变化对表面折射率的影响,描述了扩散引起的波导内部诱导应力变化设计了测试波导损耗以及波导表面折射率改变的实验装置,对尺寸10mm×10mm×1.5mm和10mm×5mm×1.5mm两组BK7玻璃基片上的玻璃波导进行了测试,测试结果与理论吻合较好. 相似文献
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在高能碰撞中,e+e-湮没的电荷多重性可用负二项分布很好地描绘.阶乘矩F2、F3和F4仅由3k表示出来. 相似文献
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Based on a relativistic quark model approach, the transition properties of the first nucleon resonance △(1232), and the coupling constants gπNN, g△πN are investigated. Tvo different vays to remove the center of mass motion are considered. The results of the relativistic approaches with and without center ofmass correction are compared with those of nonrelativistic constituent quark model. Moreover, pion meson cloud effect on these calculated observables is explicitly addressed. Better results are obtained by taking the pion meson cloud into account. 相似文献
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We obtain mass spectra of the light and heavy meson-antimeson(molecular states) sectors by using a nonrelativistic potential model with Coulomb and one pion exchange potential terms for meson-meson interaction.The digamma decay widths are also obtained for the light sector.We compare our results with available experimental and theoretical data. 相似文献
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用微扰QCD对B(s)→Φρ衰变进行了研究,考虑了因子化和非因子化图的贡献,得出了B(s)→Φρ衰变的分支比以及纵向极化衰变、横向极化衰变之比,所得到的结果与现在的实验数据吻合. 相似文献
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TANG Ze-Bo 《中国物理 C》2007,31(12)
We present the preliminary results on the spin alignment matrix elementρ_(00)for vector mesons K~(*0)(892)andφ(1020)in mid-central(20%—60%)Au Au and p p collisions at S_(NN)~(1/2)=200GeV.The values ofρ_(00)with respect to reaction plane in Au Au collisions are 0.36±0.02(stat)±0.13(sys)for K~(*0)(892)and 0.38±0.01(stat)±0.04(sys)forφ(1020).No evident global spin alignment with respect to reaction plane is observed in the measured p_T region up to 5GeV/c with current sensitivity,ρ_(00)with respect to the production plane of the vector meson is also measured for K~(*0)(892)andφ(1020)in Au Au collisions,and forφ(1020)in p p collisions.No significant difference for theρ_(00)between Au Au and p p collisions is observed with our data sample. 相似文献
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The phenomenological non-relativistic quark model has been employed to obtain the ground state masses of light vector mesons and their radially excited states and their decay widths.The full hamiltonian used in the investigation has kinetic energy,the confinement potential and the one-gluon-exchange potential.A good agreement is obtained with the experimental masses and their leptonic decay widths. 相似文献
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The phenomenological non-relativistic quark model has been employed to obtain the ground state masses of light vector mesons and their radially excited states and their decay widths.The full hamiltonian used in the investigation has kinetic energy,the confinement potential and the one-gluon-exchange potential.A good agreement is obtained with the experimental masses and their leptonic decay widths. 相似文献
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对f0(400—1200)的物理本质进行了探讨,将其分解为三部分:t道ρ介子和f2(1270)介子交换部分以及一个很宽的s道共振态f0(X).在ππ不变质量1.2GeV以下,用t道ρ介子交换就可以很好地解释同位旋为2的ππS波散射实验数据.但是,在能量高于1.2GeV时,t道f2(1270)介子交换的贡献必须计入.利用同位旋为2的ππS波散射过程对t道ρ介子和f2(1270)介子交换中的形状因子进行约束,通过重新拟合CERN-Munich(CM)实验数据来获得f0(X)的参数.结果表明,确实需要引入一个在1.6—1.7GeV附近具有极点的较宽的0++的共振态,其极点是(1.69–0.26i)GeV. 相似文献
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Avery P Freyberger A Rodriguez J Stephens R Yelton J Cinabro D Henderson S Kinoshita K Liu T Saulnier M Wilson R Yamamoto H Ong B Selen M Sadoff AJ Ammar R Ball S Baringer P Coppage D Copty N Davis R Hancock N Kelly M Kwak N Lam H Kubota Y Lattery M Nelson JK Patton S Perticone D Poling R Savinov V Schrenk S Wang R Alam MS Kim IJ Nemati B O'Neill JJ Romero V Severini H Sun CR Zoeller MM Crawford G Daubenmier CM Fulton R Fujino D Gan KK Honscheid K Kagan H Kass R Lee J Malchow R Morrow F 《Physical review letters》1993,71(15):2391-2395