Mass and decays of Brout-Englert-Higgs scalar with extra generations

The higher bound on the mass of the Brout-Englert-Higgs scalar boson arising from radiative corrections is not stable when the Standard Model is extended to include nondecoupling particles. In particular, additional generations of fermions allow for a heavier scalar. We investigate how the decay branchings of the scalar boson are affected by the opening of new channels. The text was submitted by the authors in English.     

CKM pattern from localized generations in extra dimension

We revisit the issue of the quark masses and mixing angles in the framework of large extra dimension. We consider three identical standard model families resulting from higher-dimensional fields localized on different branes embedded in a large extra dimension. Furthermore we use a decaying profile in the bulk different form previous works. With the Higgs field also localized on a different brane, the hierarchy of masses between the families results from their different positions in the extra space. When the left-handed doublet and the right-handed singlets are localized with different couplings on the branes, we found a set of brane locations in one extra dimension which leads to the correct quark masses and mixing angles with the sufficient strength of CP-violation. We see that the decaying profile of the Higgs field plays a crucial role for producing the hierarchies in a rather natural way.     

再论空穴和霍尔效应

笔者曾谈论过空穴和霍尔效应问题[1],试图回答,在本质上都是电子移动的情况下, 为什么自由电子导电 (n 型半导体)和空穴导电 (p 型半导体)会出现相反方向的霍尔电压.笔者想用更通俗的方式再论述一下此问题.     

Fundamental symmetries and precision measurements on trapped particles

The tests of fundamental symmetries (CPT symmetry and the equivalence principle for antiparticles) that can be deduced from high-precision frequency measurements on trapped particles are reviewed.     

Optical methods for precision measurements

Contactless measuring techniques are becoming increasingly important for industrial applications. The use of a laser, solid-state detector arrays and powerful small computers leads to a very efficient fringe analysis in holography as well as in Moiré and speckle techniques. Due to the computer analysis, much more information can be extracted from interferograms, leading to higher sensitivities and accuracies. The application of different fringe analysis procedures is discussed, together with some potentials of the application of interferometry, holography, and speckle and Moiré techniques.     

Constraints on proton structure from precision atomic-physics measurements

Ground-state hyperfine splittings in hydrogen and muonium are very well measured. Their difference, after correcting for magnetic moment and reduced mass effects, is due solely to proton structure-the large QED contributions for a pointlike nucleus essentially cancel. The rescaled hyperfine difference depends on the Zemach radius, a fundamental measure of the proton, computed as an integral over a product of electric and magnetic proton form factors. The determination of the Zemach radius, (1.019+/-0.016) fm, from atomic physics tightly constrains fits to accelerator measurements of proton form factors. Conversely, we can use muonium data to extract an experimental value for QED corrections to hydrogenic hyperfine data. There is a significant discrepancy between measurement and theory, in the same direction as a corresponding discrepancy in positronium.     

Limitations on the precision of atomic meanlife measurements

Uncertainty estimates in atomic meanlife measurements are usually obtained by statistical inference based on the hypothesis that the exponential decay law is exact and the distribution of random errors about it is Gaussian. At some level of precision these parameter evaluation methods must be accompanied by additional hypothesis testing. Possible limitations on these accuracies are examined in the light of recent measurements and calculations, and are quantitatively studied through the simulation and fitting of several alternative models.     

Ion traps --Precision measurements and more

Today ion traps are an important experimental tool. Applications range from high-precision measurements of masses and moments, realization of atomic clocks, to the study of ion chemical reactions. Ion traps have gained particular importance in the field of nuclear physics where they are used for the precise determination of nuclear binding energies, decay studies, and radioactive ion beam manipulation. Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002 RID="a" ID="a"e-mail: bollen@nscl.msu.edu