共查询到20条相似文献,搜索用时 31 毫秒
1.
Using the B-S wave functions of mesons in the massive straton model[1], we discuss their weak decay, electromagnetic decay, and particularly hadronic decay processes. Not only fπ≈fK, 1-→l+l- rate are successfully explained, the predicted widths for various hadronic decays are also in good agreement with experimental data. 相似文献
2.
C. Ruwiedel M. Schumacher N. Wermes 《The European Physical Journal C - Particles and Fields》2007,51(2):385-414
The prospects for the measurement of the tensor structure of the vertex between a standard model Higgs boson and two weak
gauge bosons using the distribution of the azimuthal angles between the two tagging jets in the weak boson fusion channel
are studied in a Monte Carlo analysis using the fast simulation of the ATLAS detector. The decay channels H→τ+τ-→ll+4ν, H→τ+τ-→lh+3ν at mH=120 GeV and H→W+W-→llνν at mH=160 GeV are used in the analysis. For a standard model Higgs boson it is found that purely anomalous couplings are expected
to be excluded at a confidence level corresponding to 2σ or more at mH=120 GeV and more than 5σ at mH=160 GeV from 30 fb-1 of data. With a value of 1 roughly reproducing the standard model cross section for a purely anomalous coupling, the standard
deviation in a measurement of a contribution of a CP even anomalous coupling in addition to the standard model coupling is
estimated to be 0.20 at mH=120 GeV and 0.09 at mH=160 GeV. 相似文献
3.
JIANG Xiang-Dong 《中国物理C(英文版)》1984,8(3):272-278
A model of grand unified theory based on SU(6) gauge group is proposed. It can accommodate two generations of ordinary fermions with V-A weak coupling and two generations of anomalous fermions with V+A weak coupling. In this model a new discrete symmetry is introduced which insures existence of fermions with lower masses when SU(6) gauge symmetry is spontaneously broken. We choose simple Higgs fields with appropriate vacuum expectation values so that the masses of anomalous fermions are heavier than those of ordinary fermions. This model also gives the same value of Weinberg angle, sin2θw=3/8, as in the usual SU(5) grand unified model at the grand unified scale. 相似文献
4.
WU Lu-Sen XIAO Zhen-Jun 《理论物理通讯》2007,48(3):502-508
In this paper, we present the exact calculations for the vertex ^-sγb and ^sZb in the unitary gauge. We find that (a) the divergent- and μ-dependent terms are left in the effective vertex function Г^γμ(p, k) for b → sγ transition even after we sum up the contributions from four related Feynman diagrams; (b) for an on-shell photon, such terms do not contribute et al.; (c) for off-shell photon, these terms will be canceled when the contributions from both vertex ^sγb and ^sZb are taken into account simultaneously, and therefore the finite and gauge-independent function Zo(xt) = Co(xt) + Do(xt)/4, which governs the semi-leptonic decay b → sl^- l^+, is derived in the unitary gauge. 相似文献
5.
本文在文献[1]基础上讨论由一对正反层子组成的介子结构波函数。假定层子质量很重,相互作用是谐振子位阱,旋量耦合方式符合一定的要求,则可以普遍给出以下结果:(1)自动给出质量谱的平方等距关系,又可以避免通常谐振子基态能级过高的困难;(2)如果层子原始弱流为V-A型,层子原始电磁流无反常磁矩项,可以解决赝标介子二体轻子衰变Cabibbo角的不谐调和矢量介子衰变到e+e-几率比的困难;(3)只要在相互作用中引入很小比例的SU(3)破坏项,就足以解释现有介子质量的SU(3)分裂。这就对为什么K-π质量差3.5倍却在许多情况下表现有相当好的SU(3)对称性给以一个合理解释;(4)方程的展开和波函数都有较好的近似性;(5)介子中层子反层子分布半径与现有关于介子电磁半径的实验量级是可以谐调的;(6)介子结构波函数的旋量结构和动量结构都是完全确定的。 相似文献
6.
In a combined investigation of B→K(*)l+l- decays, constraints on the related couplings in family non-universal Z' models are derived. We find that within the allowed parameter space, the recently observed forward-backward asymmetry in the B→K(*)l+l- decay can be explained by flipping the signs of the Wilson coefficients C9eff and C10. With the obtained constraints, we also calculate the branching ratio of the Bs→μ+μ- decay. The upper bound of our prediction is nearly an order of magnitude smaller than the upper bound given by the CDF Collaboration recently. 相似文献
7.
Toshiyuki Kuruma 《Zeitschrift fur Physik C Particles and Fields》1993,57(4):551-558
The top quark, once produced, should be an important window to the electroweak symmetry breaking sector. We compute electroweak radiative corrections to the decay processt→b+W + in order to extract information on the Higgs sector and to fix the background in searches for a possible new physics contribution. The large Yukawa coupling of the top quark induces a new form factor through vertex corrections and causes discrepancy from the tree-level longitudinalW-boson production fraction, but the effect is of order 1% or less form H<1 TeV. 相似文献
8.
本文应用戴逊表示对层子击出图形进行更严格的研究,以考察:这种机制是否确能给出无标度性;如果能够,它是否要求层子质量很小,以及ν和q2取大值的具体标准是什么?结果表明,在ν足够大时,层子击出图形能给出无标度性,但最初结果与Bjorken的不同,这里得到的是W1=νf1(x),W2=f2(x)。只有借助于击出图形为主(对深度非弹性散射)的假定,应用规范条件,才能压低W1和W2而得到Bjorken无标度性。另外,无标度性的得出,只要求ν取大值(按照某些确定的标准),对q2并无限制。层子质量M亦不要求比核子小。理论上,对于任意的M值,只要ν足够大,都将得到无标度性。 相似文献
9.
J.B. Kogut 《Physics Reports》1980,67(1):67-102
Two topics of lattice gauge theory are reviewed. They include string tension and β-function calculations by strong coupling Hamiltonian methods for SU(3) gauge fields in 3 + 1 dimensions, and a 1/N-expansion for discrete gauge and spin systems in all dimensions. The SU(3) calculations give solid evidence for the coexistence of quark confinement and asymptotic freedom in the renormalized continuum limit of the lattice theory. The crossover between weak and strong coupling behavior in the theory is seen to be a weak coupling but non-perturbative effect. Quantitative relationships between perturbative and non-perturbative renormalization schemes are obtained for the O(N) nonlinear sigma models in 1 + 1 dimensions as well as the range theory in 3 + 1 dimensions. Analysis of the strong coupling expansion of the β-function for gauge fields suggests that it has cuts in the complex 1/g2-plane. A toy model of such a cut structure which naturally explains the abruptness of the theory's crossover from weak to strong coupling is presented. The relation of these cuts to other approaches to gauge field dynamics is discussed briefly.The dynamics underlying first order phase transitions in a wide class of lattice gauge theories is exposed by considering a class of models-P(N) gauge theories - which are soluble in the N → ∞ limit and have non-trivial phase diagrams. The first order character of the phase transitions in Potts spin systems for N #62; 4 in 1 + 1 dimensions is explained in simple terms which generalizes to P(N) gauge systems in higher dimensions. The phase diagram of Ising lattice gauge theory coupled to matter fields is obtained in a expansion. A one-plaquette model (1 time-0 space dimensions) with a first-order phase transitions in the N → ∞ limit is discussed. 相似文献
10.
The hierarchy of lepton masses is studied in a dynamical model of family (horizontal) symmetry. Left-right symmetry for both vertical (electroweak) and horizontal gauge groups is favored. The decay μ→eγ puts a strong constraint on couplings as well as on the masses of both the horizontal gauge boson and the right handed Z boson. 相似文献
11.
Isospin violating signals in the τ? → (3π)?ντ decay mode are discussed. For the τ? → π?π?π+ντ decay mode, isospin violation arises from the vector current contribution in the τ? → ωπ?ντ decay with the subsequent isospin violating ω decay into π+π?. We demonstrate that such effects may be observed in presently available data through the measurement of the interference effects of these vector current contributions with the dominating axial vector current,i. e. through a measurement of the structure functionsW F, WG, WH andW I. In the case of the τ? → π0π0π?ντ decay mode, a vector current contribution is generated by ηπ0 mixing in the decay chain τ? → η??ντ → π0π0π?ντ. We find that this effect is rather small, the magnitude of the associated interference terms being too low for present statistics. 相似文献
12.
We calculate analytically the weak radiative corrections to the weak neutral current gauge boson-bottom fermion vertex, keeping the mass mt of the internal fermion line for the relevant diagrams. We find, to order α, a hard mass-term dependence mt2/MW2 of the amplitude, for large mt values. Its origin comes from the unphysical charged Higgs coupling to fermions in the renormalizable gauge or, equivalently, from the longitudinal charged gauge boson couplings. The diagonal Z0 decay width to b-quarks decreases, due to these weak radiative corrections, by 0.6%–2.5% when the top mass mt varies from 45 to 200 GeV. 相似文献
13.
HUI Ping 《中国物理C(英文版)》2004,28(11):1146-1149
The random phase approximation (RPA) method and the Feymann-Hellman theorem are used to calculate the seventh order glueball mass of the 2+1-D SU(2) lattice gauge theory. As an approximation, the trial wave function is constructed only by single-hollow graphs. The calculated result of the seventh order glueball mass shows good scaling behavior at the weak coupling region of 1/g2=1.0-1.8(m/e2≈1.20±0.01). 相似文献
14.
We present a variational calculation of 0+- and 0++ glueball masses in 2+1 dimensional U(1) lattice gauge theory by using a Hamiltonian which possesses exact ground state and correct classical continuum limit.In deep weak coupling region,we obtain that am(0+-) decreases with 1/g2 exponentially and am(0++)=2.78g2. 相似文献
15.
We study the possibility of searching the η→e+e- rare decay on the Cooling Storage Ring (CSR) at Lanzhou. The main features of the proposed Internal Target Experiment (ITE) and External Target Facility (ETF) are included in the Monte Carlo simulation. Both the beam condition at the CSR and the major physics backgrounds are carefully taken into account. We conclude that the ITE is more suitable for such a study due to better detector acceptance and higher beam density. At the maximum designed luminosity (1034 cm-2s-1), η→e+e- events can be collected every ~400 seconds at the CSR. With a mass resolution of 1 MeV, the expected signal-to-background (S/B) ratio is around 1. 相似文献
16.
The coupling problem of the three different intermediate processes J/ψ→ωf2(1270),f2→π+π- and J/ψ→b1±(1235)π+,b1±→ωπ± included in the hadronic decay process J/ψ→ωπ+π- is discussed.The consideration of the coupling effect is very important for measuring the parameters of the resonances f2 and b1± and the helicity amplitude ratios of these reactions precisely. 相似文献
17.
On the basis of the straton model[1],using the general groundstate wave functionsof mesons and baryons given in ref.[2],we have constructed under some specific as-sumptions the meson and baryon wave functions without SU6 symmetry.We applythese wave functions to explain the mesonic and baryonic properties of the electroma-gnetic and weak interactions;many results obtained are in agreement with the experi-ments.By using the 1/2+-baryon wave functions without SU6 symmetry,we obtain ananomalous magnetic moment for the proton.There is no need to introduce an ano-malous magnetic moment for the straton in the effective Hamiltonian of electromag-netic interaction between stratons.Similarly,the magnetic moment of the neutroncan also be explained. 相似文献
18.
Angular Distributions and Generalized Moment Analysis for the Doubly Radiative Decay J/ψ→γγV
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The doubly radiative decay process J/ψ→γ+X,X→γ+V,V→2P(or 3P) is discussed in this paper.For the intermediate state X with various spin-parity JP,the corresponding helicity formalism of angular distribution formulas and the moments developed from the generalized moment analysis are presented.They are helpful for determining the spin of the intermediate state. 相似文献
19.
In the framework of top-color assisted
technicolor (TC2) theory, we study the four decay processes of charged top-pion, i.e.,
Π+t→ t\bar{b},
Π+t→ c\bar{b},
Π+t→
W+γ, Π+t→ W+Z0. The decay
branching ratio of these modes are calculated. The results show
that the main decay channels of charged top-pion are the tree
level modes: Π+t → t\bar{b} and Π+t
→ c\bar{b}. Light Π+t is easier to be detected
than heavy one at future coliders. So, the study provides us with some
useful informations to search for charged top-pion. 相似文献
20.
In this paper a unified electro-weak model for leptons based on the SU(3) gaugegroup is suggested by means of four kinds of realization for the generators of thegroup. For all low energy electro-weak processes, this model predicts the same resultsas the conventional Weinberg-Salam model does. The Weinberg angle is shown to be sin2θw=1/4 in a natural way. When the Higgs self potential respects a discrete symme-try Φ→-Φ, a new conserved quantum number called weak strangeness emerges fromthe model after spontaneous symmetry breaking. In the present model there existanother four heavy vector gauge bosons V± and U±± together with some heavyfermions and Higgs scalars, which have non vanishing weak strangeness quantumnumbers. These weak strange particles have no direct couplings with leptons. Theirexistence will not influence the low energy electro-weak processes. Nevertheless, theycan be produced in pairs in high energy collisions and the lightest of them should bestable if the conservation of weak strangeness is exact. The experimental implicationsand the possibility of violation of the conservation of weak strangeness are also dis-cussed. 相似文献