CPT-violating effects in muon decay

We consider low-energy CPT-violating modifications in charged current weak interactions and analyze possible ramifications in muon and antimuon decays. We calculate the lifetime of muon and antimuon with these modifications, and from the result, put bounds on the CPT-violating parameters. Moreover, we elaborate on the muon and antimuon decay rate differentials in electron energy and spatial angle, which entail interesting phenomenological consequences presenting new ways to constrain CPT violation in charged lepton decays.     

Oscillation of Dirac and Majorana neutrinos from muon decay in the case of a general interaction

We analyse the possibility of distinguishing Dirac and Majorana neutrinos in future neutrino factory experiments in which neutrinos are produced in muon decay when, in addition to a vector type as in the SM, there are also scalar interactions. We check this possibility in an experiment with a near detector, where the observed neutrinos do not oscillate, and in a far detector, after the neutrino oscillations. Neglecting higher-order corrections, even neutrino observation in the near detector does not give a chance to differentiate their character. However, this possibility appears in the leading-order after the neutrino oscillations observed in far detector.     

Enhanced electroweak radiative corrections in SUSY and precision data

Enhanced radiative corrections generated in SUSY extensions of the Standard Model spoil the fit of the precision data (Z-boson decay parameters and W-boson mass). This negative effect is washed out for heavy enough squarks, because of the decoupling property of SUSY models. We find that even for light squarks the enhanced radiative corrections can be small. In this case substantial mixing is necessary.     

Radiative corrections to muon and beta decay in the intermediate Vector Boson theory

The radiative corrections to muon and beta decay are examined in detail using the ξ-limiting formalism ofLee andYang. The electron spectra for both decays are calculated. It is found that the muon lifetime discrepancy is reduced considerably if one considers, quantitatively, the effect of strong interactions on the weak vector coupling constant as determined from the neutron's lifetime.     

Radiative corrections to muon decay in leading and next-to-leading approximation for electron spectrum

We have noted that the electron spectrum of muon decay in the leading logarithmic approximation calculated in two lowest orders of the perturbation theory in the paper of Berman (1958), can be reproduced by the parton language. This fact permits one to generalize the result to all orders of the perturbation theory using the structure function method.     

Hard meson corrections to the amplitude for radiative muon capture and the elementary particle method

Hard meson corrections to the amplitude of radiative muon capture on the proton are derived within the framework of vector meson dominance in the tree approximation. The weak form factors are mediated by π, ρ and A₁ mesons which may radiate. The model reproduces the terms in the amplitude of lower order in the momentum transfers as derived from low-energy theorems and determines higher-order terms which are otherwise ambiguous or undetermined. Arguments are given why a similar approach to radiative muon capture in nuclei in an elementary particle method is expected to fail.     

Hard meson corrections to the amplitude for radiative muon capture and the elementary particle method

Hard meson corrections to the amplitude of radiative muon capture on the proton are derived within the framework of vector meson dominance in the tree approximation. The weak form factors are mediated by π, ρ and A₁ mesons which may radiate. The model reproduces the terms in the amplitude of lower order in the momentum transfers as derived from low-energy theorems and determines higher-order terms which are otherwise ambiguous or undetermined. Arguments are given why a similar approach to radiative muon capture in nuclei in an elementary particle method is expected to fail.     

高离化态金离子的辐射复合及其退激发过程的理论研究

利用基于多组态Dirac-Fock方法的程序包GRASP92和RATIP以及最新发展的RERR06程序,详细计算了高离化态金离子(类镍Au51+、类铜Au50+和类锌Au49+)俘获一个自由电子到nl(n=4—8,l=0—3)壳层的辐射复合谱以及相应的辐射退激发谱.理论计算的辐射复合谱很好地重现了实验谱.研究结果表明:对类镍Au51+、类铜Au50+和类锌Au49+而言,将一个自由电子俘获到n=4壳层的概率最大;在辐射复合过程之后,处在n=4壳层的俘获电子的辐射退激发谱线最强,并且体现了整个辐射退激发谱的主要特征.     

Recent progress on isospin breaking corrections and their impact on the muon g－2 value

We describe some recent results on isospin breaking corrections which are of relevance for predictions of the leading order hadronic contribution to the muon anomalous magnetic moment aμ^had.LO when using τ lepton data. When these corrections are applied to the new combined data on the π^±π^0 spectral function, the prediction for aμ^had.LO based on τ lepton data gets closer to the one obtained using e^＋e^- data.     

Recent progress on isospin breaking corrections and their impact on the muon g-2 value

We describe some recent results on isospin breaking corrections which are of relevance for predictions of the leading order hadronic contribution to the muon anomalous magnetic moment ahμa d,LOwhen using τ lepton data.When these corrections are applied to the new combined data on the π±π0 spectral function,the prediction for aμha d,LObased on τ lepton data gets closer to the one obtained using e+e-data.     

New non-abelian couplings and radiative corrections to the main decay of the top quark

We calculate first order radiative corrections to the main decay of the top quark,tb+W, beyond the Standard Model, by grafting onto the standard lagrangian (using the terminology of de Rújula, Gavela, Hernandez and Massó), a new operator, which respects the gauge symmetry of the Standard Model and modifies theZ ⁰ W ⁺ W ^–,W ⁺ W ^– vertices In our renormalization scheme we use ,G _F,M _Z as input parameters. Them _t dependence is given where we use =1 TeV as a possible scale of the new physics. Form _t =150(200) GeV and =1 TeV, the maximal effect due to the new non-abelian couplings, is to change the relative size of the electroweak radiative corrections of the Standard Model by adding a value of –2.98(–6.96)%, i.e. from a value of 5.55(3.26)% to 2.57(–3.7)%.     

类铝离子基态能量的相对论修正和Z相关修正

以Breit-Pauli哈密顿的球张量形式为基础,借助不可约张量理论,在拉卡表象下计算了类铝体系基态能量相对论修正(包括相对论质量修正项、单体和双体达尔文修正项、自旋-自旋接触和轨道-轨道相互作用项)。在此基础上,引入了一个与核电荷数Z相关的能量修正项,用以弥补因忽略能量的其它高阶项对原子体系能量的影响。计算结果与实验值非常接近。     

Asphericity in the Fermi Surface and Fermi Energy of Na-K, Na-Rb and Na-Cs Binary Alloys

Detailed theoretical investigations into asphericity in the Fermi surface (FS) and Fermi energy (FE) ofNa1_xKx, Na1_xRbx, and Na1_xCsx binary solid solutions are carried out for the first time. The alloying behavior ofthe K, Rb, and Cs with the Na generates the Fermi surface distortion (FSD) of bce simple metals. The FS of Na-K,Na-Rb, and Na-Cs solid solution is a distorted sphere with the largest deviation along [110]. We have found that theimpact of local-field correction function on FSD is maximun at [100] point and minimum at [111] point. The exchangeand correlation effect is found to suppress the value of FE.     

Xe54+离子与Xe原子碰撞过程中的辐射电子俘获及退激发辐射的理论研究

基于多组态Dirac-Fock理论方法和冲量近似, 对Xe⁵⁴⁺与Xe在197 MeV/u碰撞能量下, 炮弹离子的俘获及退激发过程进行了理论研究. 计算了炮弹离子从中性靶原子俘获一个电子到nl (n=1, 2, 3, 4, 5; l=s, p, d) 轨道上的辐射电子俘获截面和相应的辐射光子能量, 以及俘获末态退激发辐射跃迁的能量和概率. 结合这些计算结果, 进一步模拟了碰撞产生的炮弹离子的退激发X射线谱的结构, 并与兰州重离子加速器装置上的最新实验观测结果进行了比较, 符合得很好.     

Measurement of and the dipion contribution to the muon anomaly with the KLOE detector

We have measured the cross section σ(e⁺e⁻→π⁺π⁻γ(γ)) at DAΦNE, the Frascati -factory, using events with initial state radiation photons emitted at small angle and inclusive of final state radiation. We present the analysis of a new data set corresponding to an integrated luminosity of 240 pb⁻¹. We have achieved a reduced systematic uncertainty with respect to previously published KLOE results. From the cross section we obtain the pion form factor and the contribution to the muon magnetic anomaly from two-pion states in the mass range 0.592<M_ππ<0.975 GeV. For the latter we find Δ^ππa_μ=(387.2±0.5_stat±2.4_exp±2.3_th)×10⁻¹⁰.     

原子核体积和质量效应对较轻元素及同位素类氢离子能级的修正

在类氢离子电子束缚能一级相对论修正的基础上,计算了原子核的体积效应及质量效应对较轻元素及同位素类氢离子能级的修正量,结果显示,原子核的体积及质量效应不仅导致同位异核氢及类氢离子精细结构能级出现分裂,还会导致类氢离子精细结构能级的简并消失。     

Relativistic studies of the decay constants of S wave and P wave mesons

Relativistic corrections are important in hadronic physics since even for the heavy hadrons there are sizable relativistic corrections. Therefore one should use a relativistic model to describe the higher excited states. This note summarizes our predictions for the decay constants of the S wave and P wave heavy mesons by means of the instantaneous relativistic Bethe Salpeter equation (Salpeter equation).     

QCD and electro-weak corrections to the production of Higgs+2 jets at the LHC

We present complete next-to-leading-order (NLO) QCD correction and electro-weak (EW) correction to the production cross section of Higgs-Boson in association with two hard quark jets by using Monte-Carlo numerical calculation program, HAWK, for various photon parton distribution functions at the Large Hadron Collider with center of mass energy 7, 8, 13, and 14 TeV without and with typical vector-Boson-fusion cuts on the tagging jets. In our calculation we include complete contribution from the full set of t-channel, u-channel and s-channel Feynman diagrams, and corresponding interferences as well as NLO QCD and EW corrections.     

Relativistic studies of the decay constants of S wave and P wave mesons

Relativistic corrections are important in hadronic physics since even for the heavy hadrons there are sizable relativistic corrections. Therefore one should use a relativistic model to describe the higher excited states. This note summarizes our predictions for the decay constants of the S wave and P wave heavy mesons by means of the instantaneous relativistic Bethe Salpeter equation （Salpeter equation）.