Ambiguities of theoretical parameters and CP/T violation in neutrino factories

We study the optimal setup for observation of the CP asymmetry in neutrino factory experiments --- the baseline length, the muon energy and the analysis method. First, we point out that the statistical quantity which has been used in previous works doesn't represent the CP asymmetry. Then we propose the more suitable quantity, $\equiv \chi^{2}_{2}$, which is sensitive to the CP asymmetry. We investigate the behavior of $\chi^{2}_{2}$ with ambiguities of the theoretical parameters. The fake CP asymmetry due to the matter effect increases with the baseline length and hence the error in the estimation of the fake CP asymmetry grows with the baseline length due to the ambiguities of the theoretical parameters. Namely, we lose the sensitivity to the genuine CP-violation effect in longer baseline.Comment: 8pages, 2figures, Talk given by J. Sato at Joint U.S. / Japan Workshop on New Initiatives in Muon Lepton Flavor Violation and Neutrino Oscillation with High Intense Muon and Neutrino Sources, Honolulu, Hawaii, 2-6 Oct 200

Large Lepton Mixing in a Coset-space Family Unification on E7/SU(5)×U(1)3E_7/SU(5) \times U(1)^3

We study a coset-space unification model for families based on $E_7/SU(5) \times U(1)^3$. We find that qualitative structure of quark and lepton mass matrices in this model describes very well the observation. We stress, in particular, that the large mixing angle, $\sin^22\theta_{\nu_\mu\nu_\tau} \simeq 1$, required for the atmospheric neutrino oscillation reported by the SuperKamiokande collaboration, is naturally obtained, which is a consequence of unparallel family structure in the present coset-space unification.Comment: 8 pages, Latex2

A human colonic crypt culture system to study regulation of stem cell-driven tissue renewal and physiological function

The intestinal epithelium is one of the most rapidly renewing tissues in the human body and fulfils vital physiological roles such as barrier function and transport of nutrients and fluid. Investigation of gut epithelial physiology in health and disease has been hampered by the lack of ex vivo models of the native human intestinal epithelium. Recently, remarkable progress has been made in defining intestinal stem cells and in generating intestinal organoid cultures. In parallel, we have developed a 3D culture system of the native human colonic epithelium that recapitulates the topological hierarchy of stem cell-driven tissue renewal and permits the physiological study of native polarized epithelial cells. Here we describe methods to establish 3D cultures of intact human colonic crypts and conduct real-time imaging of intestinal tissue renewal, cellular signalling, and physiological function, in conjunction with manipulation of gene expression by lentiviral or adenoviral transduction. Visualization of mRNA- and protein-expression patterns in cultured human colonic crypts, and cross-validation with crypts derived from fixed mucosal biopsies, is also described. Alongside studies using intestinal organoids, the near-native human colonic crypt culture model will help to bridge the gap that exists between investigation of colon cancer cell lines and/or animal (tissue) studies, and progression to clinical trials. To this end, the near native human colonic crypt model provides a platform to aid the development of novel strategies for the prevention of inflammatory bowel disease and cancer

Vortical amplification of magnetic field at inward shock of supernova remnant Cassiopeia A

We present an interpretation of the time variability of the $X$-ray flux recently reported from a multi-epoch campaign of $15$ years observations of the supernova remnant Cassiopeia A by {\it Chandra}. We show for the first time quantitatively that the $[4.2-6]$ keV non-thermal flux increase up to $50\%$ traces the growth of the magnetic field due to vortical amplification mechanism at a reflection inward shock colliding with inner overdensities. The fast synchrotron cooling as compared with shock-acceleration time scale qualitatively supports the flux decrease.Comment: 5 pages, 2 figures, PRL in pres

On the Magnetic Excitation Spectra of High Tc Cu Oxides up to the Energies far above the Resonance Energy

Magnetic excitation spectra c"(q,w) of YBa2Cu3Oy and La214 systems have been studied. For La1.88Sr0.12CuO4, c"(q,w) have been measured up to ~30 meV and existing data have been analyzed up to the energy w~150 meV by using the phenomenological expression of the generalized magnetic susceptibility c(q,w)=c0(q,w)/{1+J(q)c0(q,w)}, where c0(q,w) is the susceptibility of the electrons without the exchange coupling J(q) among them. In the relatively low energy region up to slightly above the resonance energy Er, it has been reported by the authors' group that the expression can explain characteristics of the q- and w-dependence of the spectra of YBa2Cu3Oy (YBCO or YBCOy). Here, it is also pointed out that the expression can reproduce the rotation of four incommensurate peaks of c"(q,w) within the a*-b* plane about (p/a, p/a) {or so-called (p, p)} point by 45 degree, which occurs as w goes to the energy region far above Er from E below Er. For La2-xSrxCuO4 and La2-xBaxCuO4, agreements between the observed results and the calculations are less satisfactory than for YBCO, indicating that we have to take account of the existence of the "stripes" to consistently explain the observed c"(q,w) of La214 system especially near x=1/8.Comment: 14 pages, 5 figure

X-ray Absorption Study of Pulsed Laser Deposited Boron Nitride Films

B and N K-edge x-ray absorption spectroscopy measurements have been performed on three BN thin films grown on Si substrates using ion-assisted pulsed laser deposition. Comparison of the films' spectra to those of several single-phase BN powder standards shows that the films consist primarily of $sp^2$ bonds. Other features in the films' spectra suggest the presence of secondary phases, possibly cubic or rhombohedral BN. Films grown at higher deposition rates and higher ion-beam voltages are found to be more disordered, in agreement with previous work.Comment: 7 pages, LaTeX 2.09. Figures not included, but available by fax. Send email to [email protected]