共查询到20条相似文献,搜索用时 15 毫秒
1.
《Physics letters. A》1998,243(4):215-222
The features of the low-lying spectrum and the complete set of quantum numbers of each of the low-lying states of a (e+e+e−e−) system have been deduced based on symmetry. 相似文献
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The triple differential cross section of the Ar 2p orbital in a highly asymmetric geometry is calculated by using a modified distorted wave Born approximation method. A short-range polarization potential via density-functional theory is included in our calculations. It is shown that polarization potential is particularly important for calculations of the triple differential cross section. 相似文献
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《Nuclear Physics B》1996,474(1):72-84
We consider indirect searches for additional neutral vector bosons in e+e− and e−e− collisions, and compare these two linear collider modes with similar analysis procedures and assumptions. Discovery limits and resolving power are discussed in a model-independent way. 相似文献
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《Physics letters. [Part B]》1986,180(4):353-357
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《Nuclear Physics B》1986,278(1):1-25
We study in detail production and decay of neutralinos in e+e− annihilation. Formulae for the cross section, the single lepton, lepton pair, and missing energy spectra are given. Particular attention is paid to the mixing of gauginos and higgsinos. In order to illustrate its importance numerical results for four different mixing scenarios are presented. 相似文献
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A. I. Ahmadov 《Physics of Atomic Nuclei》2006,69(1):51-58
The production of the lightest stable neutralino in the process
including general mixing of gauginos and Higgsinos is studied. General formulas for the differential cross section are presented.
The dependence of the differential cross section on the photon energy spectrum and also the dependence of the total cross
section on the beam energies for three different mixing scenarios are illustrated.
The text was submitted by the author in English. 相似文献
10.
S. Fajfer 《The European Physical Journal C - Particles and Fields》2011,71(1):307-312
The decaysK +???? + e + e ?,K S???? 0 e + e ? andK L???? 0 e + e ? are reinvestigated within the framework of chiral perturbation theory. The counterterms induced by strong, electromagnetic and weak interactions are determined assuming the resonance exchange. The weak deformation model, the factorization model and the largeN c limit are used to create a weak Lagrangian. It is found that the results of the first two approaches depend on theH 1 coupling, defined in the effective chiral Lagrangian of theO(p 4) order. The set of parameters used in the extended Nambu and Jona-Lasinio model can accommodeteK +???? + e + e ? decay rate within the factorization approach. The CP violatingK L???? 0 e + e ? decay rate is discussed. 相似文献
11.
The \(e^ + e^ - \to b\bar bv\bar v\) process, where υ is an electron, muon, or τ-lepton neutrino, is analyzed in detail for the general form of the coupling constant of a Higgs boson with b quarks, with the (m b /v)(a+Iγ5b) parameterization of the \(Hb\bar b\) interaction. This process is shown to be highly sensitive to this coupling constant. Experiments at the future with \(\sqrt s = 500 - GeV\) linear collider will provide limits of 2 and 20% for deviations of the parameters a and b, respectively, from their Standard Model values. Results concerning the \(e^ + e^ - \to b\bar bv\bar v\) process in combination with the independent measurements of the partial width \(\Gamma _{H \to b\bar b}\) can testify to the CP origin of the Higgs sector of the theory. 相似文献
12.
P. Simji Vishnu M. Bannur 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(9):1-4
The two widely studied thermodynamically consistent quasiparticle models are compared by studying the statistics and thermodynamics of relativistic plasma consists of (e, e +, ??). We use different density dependent dispersion relation for electron and photon with the requirment that at high temperature thermal masses go to that of corresponding perturbative results and do the calculation self-consistently. We further compare our results with previous results. 相似文献
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《Nuclear Physics A》1997,613(3):267-281
We present the first data on the exclusive (p,e+e−) reaction in a nucleus. Cross sections for populating the ground state and first excited state in the residual nucleus are presented for the reaction 11B(p, e+e−)12C at 98 MeV. The e+e− momentum vectors were measured with a high-resolution magnetic pair spectrometer. The distributions of the virtual photon invariant mass and of the direction of the electron in the virtual photon rest system are compared with a simple single-nucleon model. The (p,e+e−) cross sections are compared with corresponding data for the (p, γ) reaction obtained with the same apparatus. The (p,e+e−) cross sections show substantial enhancement over what is expected from the simple model. 相似文献
15.
E. Offermann 《Czechoslovak Journal of Physics》1993,43(3-4):387-415
The expeprimental (e, ep) program at Mainz is presented. The reaction (e, ep) without spin degrees of freedom is compared with the case when polarization observables are considered. It is demonstrated on some examples how the new information can be used to extend the knowledge of the reaction mechanism and nucleon/nuclear structure. Construction and operation of a focal-plane proton polarimeter at Mainz is described.Lectures held at the Indian-Summer School on Electromagnetic and Weak Interactions of Particles with Nuclei, Sázava, Czechoslovakia, 6–11 September 1992. 相似文献
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M. P. Rekalo 《Russian Physics Journal》1982,25(9):769-771
Density matrix elements for a Z-boson created in the reaction e++e–Z+, are computed. Two reference frames are used in computations: the center-of-mass frame of the reaction e++e–Z+ with polarization states of the Z-boson specified by the polarization 4-vector with definite helicities, and the rest frame of the Z-boson. In both cases P-odd phenomena should stipulate particular combinations of the density matrix elements. The energy behavior of the total cross-section of the process e++e–Z+ is studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 3–6, September, 1982. 相似文献
18.
《Comptes Rendus Physique》2002,3(9):1211-1222
This article gives an overview of the main experimental tests of perturbative QCD performed at LEP. It covers the following topics: determination of αs from event shapes, tests of flavour independence of αs, studies of heavy quark mass effects, differences between quark and gluon jet fragmentation and study of the triple gluon vertex. To cite this article: D. Duchesneau et al., C. R. Physique 3 (2002) 1211–1222. 相似文献
19.
A. Dewanto A. H. Chan C. H. Oh R. Chen K. Sitaram 《The European Physical Journal C - Particles and Fields》2008,57(3):515-523
We study the evolution of Lee-Yang zeros structure of generalized multiplicity distribution (GMD) in high energy collision.
Starting our study with electron-positron e
+
e
− scattering data, we extend the study by Chan and Chew (Z. Phys. C 55:503, 1992) on TASSO and AMY multiplicity data for
, 22, 34.8, 43.6 and 57 GeV to the ones from DELPHI and OPAL Collaboration for
, 133, 161, 172, 183 and 189 GeV. We compare the results with the Lee-Yang structure for proton-antiproton
at
, 546 and 900 GeV from UA5 Collaboration. Our preliminary result shows that there is indeed a change in the shape and size
of the Lee-Yang zeros with increasing energy, accompanied by the development of the so-called “ear”-like structure in the
Lee-Yang plot. We expect that the development of this “ear”-like structure is related to the “shoulder” structure in the multiplicity
data, which further indicates an ongoing phase transition from soft to semihard scattering. We also extend our prediction
to LHC’s
TeV. Insert your abstract here. 相似文献
20.
Xiaohui Liu 《The European Physical Journal C - Particles and Fields》2010,68(1-2):153-158
We study the possibility of using soft-collinear effective theory (SCET) and non-relativistic QCD (NRQCD) to investigate the exclusive J/ψ production from e + e ? annihilation. By performing a two-step matching at scale μ H and μ c respectively, we determine the SCET Wilson coefficient and run to the scale Λ~1 GeV to sum large logarithms. We apply our model to the two-body final state. In order to fit our SCET model, we estimate the upper limit on the mass of the exclusive particle. Together with the symmetry consideration, we conclude that our model is applicable to J/ψ production accompanied with an f 2 meson or a ground state glueball. Finally, we use our results to calculate the cross section for the e + e ?→J/ψ+f 2(1270) process. 相似文献