光磁共振实验反常共振信号的判断与原因分析

对光磁共振实验中各反常共振信号对应的射频信号进行了研究,提出了反常共振信号的判断方法.利用傅立叶级数展开,对反常射频信号各谐波分量的强度进行了定量分析.结果表明,反常共振信号是由射频信号中的谐波所引起,而非多量子跃迁的结果.     

Process e^-у→ e^-H in Littlest Higgs Model

In the context of the littlest Higgs （LH） model, we estimate the production cross section of the process e^-у→ e^-H in the future high-energy linear e^＋e^- collider （ILC） with the center-of-mass （CM） energy √S = 500 GeV. Our numerical results show that the contributions of the LH model Co this process are very small in most of the parameter space allowed by the electroweak precision measurement data, and are very diffcult to be detected in the future ILC experiments.     

B→K^＊у/Decay in Top-Quark Two-Higgs-Doublet Model

By employing the QCD factorization approach for the exclusive B→Vу decays, we study the exclusive decay B→K^＊у in the top-quark two-Higgs-doublet mode/（T2HDM）. Within the considered parameter space, we find the following conclusions （a） A hght charged-Higgs boson with a mass about 200 GeV is clearly excluded by the date of B→K^＊у decay, and this lower limit is comparable with that from the inclusive B→X8＊у decay; （b） The theoretical predictions for CP asymmetry of B→K^＊у in the T2HDM is always less than 1% in size; and （c） The isospin symmetry breaking for B→K^＊у decay in the SM and T2HDM considered here is around 6% in size and well consistent with the data and the general expectations.     

Functional Integrals and Collective Excitations in Boson-Fermion Model

In this paper, collective excitations in the boson-fermion model are investigated by means of functional integration method. The equations of energy gap and excitation spectrum are derived. Moreover, the Bose energy spectrum of zero wave vector Fermi fields is also calculated.     

A QCD Model Using Generalized Yang-Mills Theory

Generalized Yang-Mills theory has a covariant derivative, which contains both vector and scalar gauge bosons. Based on this theory, we construct a strong interaction model by using the group U（4）. By using this U（4） generalized Yang-Mills model, we also obtain a gauge potential solution, which can be used to explain the asymptotic behavior and color confinement.     

反常扩散:定向通过一个势能鞍点

考虑一个处于非Ohmic环境下的系统定向通过一个倒谐振子势鞍点的输运过程,给出了通过几率的解析式。结果表明在欠扩散情况下,时间有关的通过几率出现一个很强的超前峰和回流,这可能有助于理解重核熔合系统的激发函数随质心能量的慢增长机制。Directional transport of a particle in a non-Ohmic environment passing over the saddle point of a potential is considered and the analytical expression of the passing probability is obtained. Our results has shown that both overshooting and backflow are observed in the case of subdiffusion. This is a possible for understanding slow increasing of the fusion probability with the center-of-mass energy.     

Anomalous spectral behaviour of diffracted chirped Gaussian pulses in the near field

By using the Fourier transform method, analytical expressions for the axial power spectrum and near-field intensity in the spacetime domain of chirped Gaussian pulses diffracted at an aperture are derived, which permit us to study changes in spectral and temporal profiles of the chirped Gaussian pulses both analytically and numerically. Detailed numerical results and physical analysis show that spectral anomalies take place in the neighbourhood of certain critical distances, and the shifting of maximum and splitting of temporal intensity profiles appear. In particular, for ultrashort chirped pulses, there exists also spectral switch. Besides the truncation parameter, the chirp parameter and pulse duration affect the behaviour of spectral switches.     

CERN可能探测到了希格斯粒子

 ２１世纪前夕,位于日内瓦附近的欧洲核子研究中心（简称ＣＥＲＮ）的物理学家们在大型正负电子对撞机（ＬＥＰ）上做出了令科学家们激动不已的工作：他们可能探测到了梦寐以求的希格斯粒子存在的迹象。 ＣＥＲＮ现在的这台正负电子对撞机的设计能量为１００吉电子伏（ＧｅＶ）。按人们原来推测,希格斯粒子的质量很可能在１５０吉电子伏左右,看来ＬＥＰ的能量是不够的。因此,ＣＥＲＮ几年前就开始筹建大型强子对撞机（ＬＨＣ）。这台对撞机将采用１４０００吉电子伏能量的质子一质子对撞,每年能产生８０万个顶夸克,发现希格斯粒子的机会因而会大得多。     

高能加速器近期的几个大工程

 量子论和相对论的发现和确立是20世纪基础科学的最伟大的事件,它们是现代科学技术的基础,改变了整个人类的生活方式。例如,人们制造了原子弹、氢弹,建造了核电站;随着集成电路的迅速发展,计算机已经普及到家庭,人们坐在家里就可通过网络了解全世界发生的事。20世纪后期,在总结新的实验事实的基础上,理论上创立了粒子物理的标准模型,所有核物理和粒子物理的实验结果都和标准模型的预言相一致。在人们为标准模型而欢呼的时候,实验上测量到存在中微子振荡现象,说明中微子有质量,这就超出了标准模型,说明标准模型需要完善和发展。     

基于微观IBM对电子-核散射及核电磁性质的研究(I) BE理论方案

从价核子自由度出发构造出核跃迁电荷/电流密度算符,采用Dyson玻色子展开技术给出了获取核玻色子形式跃迁电荷/电流密度有效算符的一种微观方法(BE方法).利用微观相互作用玻色子模型(IBM)提供的波函数可在玻色子态空间中求出核跃迁电荷/电流密度,结合电子-核散射以及核电磁跃迁的形式理论,建立了可研究电子-核散射各种形状因子,微分散射截面以及核约化跃迁几率、电磁多极矩、核态g因子等物理量的理论方案.在一种微观sdIBM-2框架下,结合现有理论方案,初步计算了