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相对论原理在研究基本粒子的运动规律中起着十分重要的作用.它不仅要研究相对论性粒子的运动,还要研究诸如粒子的产生、衰变和湮没等问题.此外,相对论运动学在粒子物理中的应用还有其方法上的特殊性.近几年的CUSPEA试题中也常有这类考题.以下就有关基础知识,如基本变换公式、质心坐标系、粒子产生阈能、弹性散射运动学及粒子衰变等作一扼要叙述,并举例以明之.1 基本变换公式 对能量为E,动量为P,静止质量为m的粒子,下述关系式成立 E2=m2c4 p2c4粒子物理中常取光速c=1为单位,则有 E2=m2 p2这里已取c=1,故公式中所用到的质量或动量均以MeV… 相似文献
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4.弹性散射运动学 在一粒子与另一粒子的碰撞中,若只有动能的交换,粒子内部状态并无改变,则称此过程为弹性碰撞或弹性散射. 设质量为m1,动量为p的相对论性粒子沿x方向射向起始静止、质量为m2的靶粒子.碰撞后,入射粒子偏离x方向发生散射,靶粒子则发生反冲(参见图2).称入射粒子散射后的运动方向与入射方向间的夹角θ1为散射角,并称靶粒子反冲方向与入射方向间的夹角θ2为反冲角.设散射后粒子m1的动能和动量分别为T1和p1,粒子m的动能和动量则分别为T2和p2由能量守恒很容易得出,弹性散射过程中动能守恒.即 T=T1 T2(13)式中T为入射粒子的动能.… 相似文献
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本文利用置换群CG系数计算了五个粒子以内的所有SU(mn) SU(m)×SU(n)单粒子母分系数. 相似文献
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本文利用置换群CG系数计算了五个粒子以内的所有SU(mn)SU(m)×SU(n)单粒子母分系数。 相似文献
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本文借助于SU(3)群生成元四种不同的实现,建立了一个以SU(3)规范群为基础的弱电统一模型,得到W&;#177;粒子和Z粒子的质量以及它们与轻子的相互作用都与Weinberg-Salam模型的结果相同,并且给出sin2θw=1/4。这个模型要求有一个新的守恒量子数——弱奇异数存在,还存在四个重矢量粒子V&;#177;和U±±和一些重费米子以及标量粒子。它们都带有不为零的弱奇异数,都和轻子不直接耦合。它们的存在不影响低能范围内轻子的弱电作用,并且只能在高能下成对产生。它们中最轻的粒子将是稳定粒子。本文还讨论了弱奇异数守恒破坏的可能性及其后果。 相似文献
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It is shown that the (8, 8) model and explicitηπ
0 mixing successfully explain theη→3π decay width whereas the decay width calculated from the mass difference
is about one order less than the experimental value. 相似文献
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本文提出一种SU(4)⊙SU(2)⊙SU(1)统一模型. 在此模型中, 层子和轻子放于同一个多重态中, 所以它们有耦合, 但这种耦合不会导致质子衰变, 只对高能散射有效应. 此模型预言了有两种中性中间玻色子, 还算得了sin2θw=0.25, 并可使中微子有合理的质量. 相似文献
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《Physics letters. [Part B]》1988,212(3):343-350
We analyze the Yukawa couplings of the first SU(3)×SU(2)×U(1)Y orbifold models recently obtained. In these models the rank is naturally lowered due to the presence of a Fayet-Iliopoulos term associated with an “anomalous” U(1) in the four-dimensional theory. It is shown that the phenomenological viability of the models selects a favoured class of vacua. In particular, for the specific examples considered, some twisted fields with one moded oscillator acting, must acquire non-vanishing VEVs. However other possibilities may exist. We also find that all the baryon and lepton violating operators can be, in general, avoided in a completely natural way. 相似文献
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The β function behavior for SU(3)×SU(3) chiral model on 2-demensional random triangle lattice has been studied with Monte Carlo renormalization group method.The behavior is similar to that of the 4-dimensional SU(3) gauge theory,but it has a smoother transition from weak to strong coupling regions.There is no nonperturbative peak structure.The asymptotic scaling starts beyond β=5.8. 相似文献
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Yu. A. Simonov 《Physics of Atomic Nuclei》2012,75(9):1052-1066
A new approach to electroweak (EW) composite scalars is developed starting from the fundamental gauge interaction on high scale. The latter is assumed to have the group structure SU(2) L × SU(2) R × SU(4), where SU(4) is the Pati-Salam color-lepton group. The topological EW vacuum filled by instantons is explicitly constructed and the resulting equations for fermion masses exhibit spontaneous SU(2) flavor symmetry violation with possibility of very large mass ratios. 相似文献
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《Physics letters. [Part B]》1986,179(4):375-378
MCRG results are presented for the SU(3) β-function obtained from optimized blockspin transformations at β = 6.9 and 7.2. At both couplings for the shiftΔβ, corresponding to a change of length scale by a factor 2, Δβ = 0.51 is found. Although the error is large, deviations from asymptotic scaling seem to be larger than expected on the basis of earlier calculations. 相似文献
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本文讨论了重子素填充SU(3)群高维表示的可能性,指出了这些表示中核子素及其近邻的质谱特征,特别是核子素在27维表示中组成同位旋转动带。在质量小于2.6GeV的区域可能出现宽度不足0.1MeV的极窄共振。 相似文献