在φ→3γ衰变末态分析中的运用

介绍了介子工厂 (DAΦNE)KLOE组的数据分析中运动学拟合程序TELESIS的运用 .利用KLOE 2 0 0 0年在e+e- 对撞能量Ecm =1 0 2 0MeV获取的部分数据开展→γη→ 3γ和→γπ0 → 3γ的分析 ,得到介子的产生截面σe+ e- →=( 4.0 4± 0 .0 4± 0 .2 4 ) μb ,以及→γπ0 → 3γ的分截面σ→γπ0 →3γ=( 5.3± 0 .3± 0 .6)nb .这些结果与理论预言以及俄国新西伯利亚的VEPP(CMD 2 ,SND ,ND各探测器 )的相应结果一致 .     

D→PP衰变过程的末态相互作用

利用单粒子交换方法,研究了D介子衰变到两个赝标粒子中的末态相互作用.通过实验数据中抽取的强相角来分析末态相互作用的效应     

双辐射衰变J/ψ→γγV的角分布和推广的矩分析

本文讨论了J/ψ双辐射衰过程J/ψ→γ+X,X→γ+V,V→2P(或3P).对于具有不同自旋-宇称J^P的中间态X,给出了相应的角分布螺旋度形式以及由推广的矩分析方法得到的各种矩的表达式.这些公式对于确定中间态X的自旋是有帮助的.     

用Technicolor理论研究稀有辐射衰变B_c→D_sγ

在一代Ｔｅｃｈｎｉｃｏｌｏｒ（ＴＣＩ）和带有一个无质量的标量二重态（ＴＣⅡ）模型下，计算荷电的哥尔斯通粒子对衰变Ｂ＿ｃ→Ｄ＿ｓγ的贡献，并把它们同标准模型的计算相比较，发现哥尔斯通粒子对电磁企鹅图的贡献很大（ＴＣＩ下），在ＴＣⅡ下贡献较小；而对弱湮没图的贡献可以忽略不计，还对同位旋三重态粒子π＋ｐ的质量进行了约束。预言将来在ＬＨＣ上能对不同模型下的分支比Ｂｒ（Ｂｃ→Ｄｓγ）的差异进行研究，进而对不同的模型进行检验。     

北京谱仪上J/ψ→γπ~0、γη、γη—'→3γ衰变道的分支比测量

分析Ｊ／ψ衰变终态为三个光子的衰变道，测量得到了衰变道Ｊ／ψ→γπ０和Ｊ／ψ→γη’的分支比分别为Ｂｒ（Ｊ／ψ→γπ０）＝（４．６±１．１）×１０－５和Ｂｒ（Ｊ／ψ→ッη＇）＝（４．１２±０．８２）×１０－３；相对分支比Ｆ（Ｊ／ψ→γη’）／Ｆ（Ｊ／ψ→γη）＝４．７９±０．８５，在实验误差范围内与两个理论模型的预言都能一致。     

北京谱仪上J/ψ→γπ0、γη、γη'→3γ衰变道的分支比测量

分析J/ψ衰变终态为三个光子的衰变道,测量得到了衰变道J/ψ→γπ⁰和J/ψ→γη’的分支比分别为Br(J/ψ→γπ⁰)=(4.6±1.1)×10^－5和Br(J/ψ→、η＇)=(4.12±0.82)×10^－3;相对分支比F(J/ψ→γη’)/F(J/ψ→γη)=4.79±0.85,在实验误差范围内与两个理论模型的预言都能一致.     

基态介子辐射衰变中的屏蔽效应

利用屏蔽位对基态介子辐射衰变宽度进行了计算．通过与线性位的结果相比较，得到了屏蔽位结果的一些特点．     

用Technicolor理论研究稀有辐射衰变Bc→Dsγ

在一代Technicolor(TCI)和带有一个无质量的标量二重态(TCⅡ)模型下,计算荷电的哥尔斯通粒子对衰变B_c→D_sγ的贡献,并把它们同标准模型的计算相比较,发现哥尔斯通粒子对电磁企鹅图的贡献很大(TCI下),在TCⅡ下贡献较小;而对弱湮没图的贡献可以忽略不计,还对同位旋三重态粒子π+p的质量进行了约束. 预言将来在LHC上能对不同模型下的分支比Br(B_c→D_sγ)的差异进行研究,进而对不同的模型进行检验.     

B→KK衰变中的软胶子修正

应用光维QCD求和规则研究了B→KK衰变的软胶子交换修正,虽然QCD因子化方法已经计算了领头阶的因子化和硬胶子交换的α_s阶辐射修正部分,然而系统地估算所有树图和企鹅图的非因子化软胶子贡献是有价值的,我们的结果表明在B→KK衰变中软胶子效应总是使分支比值减小,约为几个百分点.     

Analysis of the φ → γπη and φ → γπ 0 π 0 decays

We study interference patterns in the φ → (γa ₀+π ⁰ ρ) → γπη and φ → (γf ₀+π ⁰ ρ) → γπ ⁰ π ⁰ reactions. Taking into account the interference, we fit the experimental data and show that the background reaction does not distort the π ⁰ η spectrum in the decay φ → γπη everywhere over the energy region and does not distort the π ⁰ π ⁰ spectrum in the decay φ → γπ ⁰ π ⁰ in the wide region of the π ⁰ π ⁰-system invariant mass, π ^ππ > 670 MeV, or when the photon energy is less than 300 MeV. We discuss the details of the scalar meson production in the radiative decays and note that there are reasonable arguments in favor of the one-loop mechanism φ → K ⁺ K ^? → γa ₀ and φ → K ⁺ K ^? → γf ₀. We also discuss distinctions between the four-quark, molecular, and two-quark models and argue that the Novosibirsk data give evidence in favor of the four-quark nature of the scalar a ₀(980) and f ₀(980) mesons.     

J/ψ→∑0Σ0衰变研究（英文）

利用北京正负电子对撞机(BEPC)上的北京谱仪(BES)收集的7.8×106个J/Ψ事例,研究了J/Ψ→Σ0衰变.其衰变分支比为BR(J/Ψ→Σ0)=(0.97±0.04±0.24)×10-3,角分布具有dN/dcosθθ=N0(1+acos2θ)的形式,a值等于-0.21±0.27±0.13.     

Neutrinoless Double-Beta Decay to Excited 0+ States

A considerable effort has been invested in studies of the two-neutrino double-beta decay to the first (and some others, too) excited 0⁺ states. These decay transitions have been considered favourable in terms of the nuclear matrix elements and the possibility to use -coincidence techniques in cleaning the background of the spectrum. A drawback in these studies is the diminished phase space for the emitted leptons due to the smaller Q value of the process. One positive result, namely the decay rate of ¹⁰⁰Mo to the first excited 0⁺ state in ¹⁰⁰Ru, already exists. Encouraged by this result one could argue that a similar situation could prevail also for the neutrinoless double-beta decay to excited 0 ⁺ states. In this article the situation has been studied for several nuclear systems with potential 0 decay to the low-lying 0⁺ states by using the quasiparticle random-phase approximation with realistic nucleon-nucleon interactions.     

Radiative Decay Bc → Ds*γ in the Technicolor with a Massless Scalar Doublet Model

Applying perturbative QCD, we study the process Bc → Dsγ in the technicolor with a massless scalar doublet model (TCMLSM). There are mainly two mechanisms contributing to the Bc → D*sγ process. One proceeds through the short distance b → sγ transition and the other through weak annihilation accompanied by a photon emission.We find that, compared with the standard model, the modification of Bc → D*sγ from πρ (the physical pions in the TCMLSM) is so small that can be neglected for the allowed mass ofπρ. The weak-annihilation contribution is found to be about one order larger than that of the electromagnetic penguin diagrams.     

Double-Beta Decay of 150Nd and 76Ge to Excited States

New results of experimental search for double beta decay of ⁷⁶Ge (2) and ¹⁵⁰Nd (0 + 2) to excited states of the daughter nuclei are presented. Data from 228 days of measurements performed with four HPGe detectors in the low background laboratory of Baksan neutrino observatory yield new limits on life-times T_1/2(0⁺ 0⁺ ₁)6.2×10²¹} yr at 90% C.L. for transition of ⁷⁶Ge to 0⁺ ₁ level of ⁷⁶Se and T_1/2(0⁺ 0⁺ ₁)1.5×10²⁰ yr at 90% C.L. for transition of ¹⁵⁰Nd to 0⁺ ₁ level of ¹⁵⁰Sm.     

Escape-Rate Formalism, Decay to Steady States, and Divergences in the Entropy-Production Rate

According to thermodynamics the irreversible entropy production of diffusive relaxation processes diverges at the boundary to the vacuum, i.e., to a state of vanishing particle density. By means of a multibaker map we point out that this divergence is not present in the spatially discrete dynamics, which brings forth the evolution equations of irreversible thermodynamics in the continuum limit. In addition, we show that the irreversible entropy production of relaxation towards a nonempty steady state is proportional to the decay rate of the thermodynamic system subjected to absorbing boundary conditions. This generalizes results of the escape rate formalism.     

Neutrinoless Double-Beta Decay to Excited 0+ States Mediated by Light Majorana Neutrinos

The neutrinoless double-beta decay (0 decay) to the first excited 0⁺ collective final state is examined for A = 76, 82, 100 and 136 nuclei by assuming light Majorana neutrino exchange mechanism. Realistic calculations of nuclear matrix elements are performed within the renormalized Quasiparticle Random Phase Approximation. Transitions to the first excited two-quadrupole phonon 0⁺ state are described within a boson expansion formalism. It is found that the ¹⁰⁰Mo is a good candidate for experimental study of the 0 decay to excited 0⁺ state due to small suppression of this transition relative to the transition to the ground state.     

Transfer of Entangled States for Two Atoms Via Cavity Decay

In this paper, the entangled states of two atoms trapped in two corresponding cavities are teleported to another two single atoms trapped in another two corresponding cavities by detecting the photons which leak out from the cavities. The most distinctive advantage of our scheme is that a direct carrier of quantum information between distant atoms is not required.     

Features of the Alpha Decay of Highly Excited States of the 10Be Nucleus

JETP Letters - The spectrum of the 10Be nucleus in a wide range of excitation energies has been calculated within the no-core shell model. An extrapolation procedure has been used to refine the...