Modified Reconstruction of Standard Model in Non-Commutative Differential Geometry

Sogami recently proposed the new idea to express Higgs particle as a kind of gauge particle by prescribing the generalized covariant derivative with gauge and Higgs fields operating on quark and lepton fields. The field strengths for both the gauge and Higgs fields are defined by the commutators of the covariant derivative by which he could obtain the Yang-Mills Higgs Lagrangian in the standard model. Inspired by Sogami's work, we present a modification of our previous scheme to formulate the spontaneously broken gauge theory in non-commutative geometry on the discrete space; Minkowski space multiplied by two points space by introducing the generation mixing matrix in operation of the generalized derivative on the more fundamental fields a_i(x,y) which compose the gauge and Higgs fields. The standard model is reconstructed according to the modified scheme, which does not yields not only any special relations between the particle masses but also the special restriction on the Higgs potential.Comment: 21 page

ALMA Temporal Phase Stability and the Effectiveness of Water Vapor Radiometer

Atacama Large Millimeter/submillimeter Array (ALMA) will be the world largest mm/submm interferometer, and currently the Early Science is ongoing, together with the commissioning and science verification (CSV). Here we present a study of the temporal phase stability of the entire ALMA system from antennas to the correlator. We verified the temporal phase stability of ALMA using data, taken during the last two years of CSV activities. The data consist of integrations on strong point sources (i.e., bright quasars) at various frequency bands, and at various baseline lengths (up to 600 m). From the observations of strong quasars for a long time (from a few tens of minutes, up to an hour), we derived the 2-point Allan Standard Deviation after the atmospheric phase correction using the 183 GHz Water Vapor Radiometer (WVR) installed in each 12 m antenna, and confirmed that the phase stability of all the baselines reached the ALMA specification. Since we applied the WVR phase correction to all the data mentioned above, we also studied the effectiveness of the WVR phase correction at various frequencies, baseline lengths, and weather conditions. The phase stability often improves a factor of 2 - 3 after the correction, and sometimes a factor of 7 improvement can be obtained. However, the corrected data still displays an increasing phase fluctuation as a function of baseline length, suggesting that the dry component (e.g., N2 and O2) in the atmosphere also contributes the phase fluctuation in the data, although the imperfection of the WVR phase correction cannot be ruled out at this moment.Comment: Proc. SPIE 8444-125, in press (7 pages, 4 figures, 1 table

Calculations of Branching Ratios for Radiative-Capture, One-Proton, and Two-Neutron Channels in the Fusion Reaction 209^{209}Bi+70^{70}Zn

We discuss the possibility of the non-one-neutron emission channels in the cold fusion reaction $^{70}$Zn + $^{209}$Bi to produce the element Z=113. For this purpose, we calculate the evaporation-residue cross sections of one-proton, radiative-capture, and two-neutron emissions relative to the one-neutron emission in the reaction $^{70}$Zn + $^{209}$Bi. To estimate the upper bounds of those quantities, we vary model parameters in the calculations, such as the level-density parameter and the height of the fission barrier. We conclude that the highest possibility is for the 2n reaction channel, and its upper bounds are 2.4$$ and at most less than 7.9% with unrealistic parameter values, under the actual experimental conditions of [J. Phys. Soc. Jpn. {\bf 73} (2004) 2593].Comment: 6 pages, 4 figure

BRST invariant Lagrangian of spontaneously broken gauge theories in noncommutative geometry

The quantization of spontaneously broken gauge theories in noncommutative geometry(NCG) has been sought for some time, because quantization is crucial for making the NCG approach a reliable and physically acceptable theory. Lee, Hwang and Ne'eman recently succeeded in realizing the BRST quantization of gauge theories in NCG in the matrix derivative approach proposed by Coquereaux et al. The present author has proposed a characteristic formulation to reconstruct a gauge theory in NCG on the discrete space $M_4\times Z_{_N}$. Since this formulation is a generalization of the differential geometry on the ordinary manifold to that on the discrete manifold, it is more familiar than other approaches. In this paper, we show that within our formulation we can obtain the BRST invariant Lagrangian in the same way as Lee, Hwang and Ne'eman and apply it to the SU(2)$\times$U(1) gauge theory.Comment: RevTeX, page

Field Theory in Noncommutative Minkowski Superspace

There is much discussion of scenarios where the space-time coordinates x^\mu are noncommutative. The discussion has been extended to include nontrivial anticommutation relations among spinor coordinates in superspace. A number of authors have studied field theoretical consequences of the deformation of N=1 superspace arising from nonanticommutativity of coordinates \theta, while leaving \bar{theta}'s anticommuting. This is possible in Euclidean superspace only. In this note we present a way to extend the discussion by making both \theta and \bar{theta} coordinates non-anticommuting in Minkowski superspace. We present a consistent algebra for the supercoordinates, find a star-product, and give the Wess-Zumino Lagrangian L_{WZ} within our model. It has two extra terms due to non(anti)commutativity. The Lagrangian in Minkowski superspace is always manifestly Hermitian and for L_{WZ} it preserves Lorentz invariance.Comment: 8 pages, added references, two-column format, published in PR

Comment on ``Quasiparticle Spectra around a Single Vortex in a d-wave Superconductor''

In a recent Letter Morita, Kohmoto and Maki analyzed the structure of quasiparticle states near a single vortex in a d-wave superconductor using an approximate version of the Bogoliubov - de Gennes theory. Their principal result is the existence of a bound state within the core region at finite energy with full rotational symmetry, which they assert explains the recent scanning tunneling microscopy results on YBCO single crystals. Here we argue that the approximation used in this work is fundamentally inadequate for the description of a d-wave vortex and that the obtained circular symmetry of the local density of states is an unphysical artifact of this approximation.Comment: 1 page REVTeX, to appear in PR

A possible involvement of ion transporter in tumor necrosis factor alpha and cycloheximide-induced apoptosis of endothelial cells.

We examined the tumor necrosis factor alpha (TNFalpha)-induced apoptosis of vascular endothelial cells from the standpoint of ion channels. Cultured vascular endothelial cells from bovine carotid artery were used. Apoptosis was determined by a propidium iodide assay. Treatment of the endothelial cells with TNFalpha and cycloheximide for 6 h induced nuclear fragmentation in a TNFalpha dose-dependent manner (1-10 ng/ml). Concomitant treatment of endothelial cells with TNFalpha at a dose of 10 ng/ml and cycloheximide at a dose of 10 microg/ml elicited endothelial cell apoptosis as high as 23.4+/-4.1% at 6 h after administration. However, 10 ng/ml TNFalpha alone elicited a little apoptosis at 6 h after its administration (% apoptosis=4.1+/-0.8%). Cycloheximide (10 microg/ml) did not induce apoptosis at all. Concomitant treatment of endothelial cells with 1 mmol/l of 4,4-diisothiocyanatostilbene-2,2-disulfonic acid, which is a chloride bicarbonate exchanger blocker, partially inhibited the TNFalpha and cycloheximide-induced endothelial cell apoptosis. On the other hand, endothelial cell apoptosis due to TNFalpha and cycloheximide was completely inhibited by benzyloxycarbonyl-Asp-CH2OC(O)-2,6-dichlorobenzene (50 micromol/l), an inhibitor of caspase. Moreover, pyrrolidine dithiocarbanate, an inhibitor of nuclear factor kappa B (NF-kappaB), also suppressed endothelial cell apoptosis induced by TNFalpha and cycloheximide completely. These findings suggest that the endothelial cell apoptosis induced by TNFalpha and cycloheximide is closely related to not only chloride ions, but also both NF-kappaB and caspase activation. That is to say, there is a possibility that chloride ions or bicarbonate (pH) may play an important role in signal transduction such as NF-kappaB and caspase activation in the apoptosis induced by TNFalpha and cycloheximide

Effects of Ground-State Correlations on High Energy Scattering off Nuclei: the Case of the Total Neutron-Nucleus Cross Section

With the aim at quantitatively investigating the longstanding problem concerning the effect of short range nucleon-nucleon correlations on scattering processes at high energies, the total neutron-nucleus cross section is calculated within a parameter-free approach which, for the first time, takes into account, simultaneously, central, spin, isospin and tensor nucleon-nucleon (NN) correlations, and Glauber elastic and Gribov inelastic shadowing corrections. Nuclei ranging from 4He to 208Pb and incident neutron momenta in the range 3 GeV/c - 300 GeV/c are considered; the commonly used approach which approximates the square of the nuclear wave function by a product of one-body densities is carefully analyzed, showing that NN correlations can play a non-negligible role in high energy scattering off nuclei.Comment: 5 pages, 3 figure