Molecular resolution imaging of protein molecules in liquid using frequency modulation atomic force microscopy

金沢大学フロンティアサイエンス機構We demonstrated molecular resolution imaging of biological samples such as bacteriorhodopsin protein molecules in purple membrane and isolated chaperonin (GroEL) protein molecules, both adsorbed on mica using frequency modulation atomic force microscope (FM-AFM) in liquid. We also showed that the frequency noise of FM-AFM in liquid can be greatly reduced by the reduction of the noise-equivalent deflection of an optical beam deflection sensor. © 2009 The Japan Society of Applied Physics

Large Solar Neutrino Mixing and Radiative Neutrino Mechanism

We find that the presence of a global $L_e-L_\mu-L_\tau$ ($\equiv L^\prime$) symmetry and an $S_2$ permutation symmetry for the $\mu$- and $\tau$-families supplemented by a discrete $Z_4$ symmetry naturally leads to almost maximal atmospheric neutrino mixing and large solar neutrino mixing, which arise, respectively, from type II seesaw mechanism initiated by an $S_2$-symmetric triplet Higgs scalar $s$ with $L^\prime=2$ and from radiative mechanism of the Zee type initiated by two singly charged scalars, an $S_2$-symmetric $h^+$ with $L^\prime=0$ and an $S_2$-antisymmetric $h^{\prime +}$ with $L^\prime=2$. The almost maximal mixing for atmospheric neutrinos is explained by the appearance of the democratic coupling of $s$ to neutrinos ensured by $S_2$ and $Z_4$ while the large mixing for solar neutrinos is explained by the similarity of $h^+$- and $h^{\prime +}$-couplings described by $f^h_+\sim f^h_-$ and $\mu_+\sim\mu_-$, where $f^h_+$ ($f^h_-$) and $\mu_+$ ($\mu_-$) stand for $h^+$ ($h^{\prime +}$)-couplings, respectively, to leptons and to Higgs scalars.Comment: RevTex, 10 pages including one figure. In Ref.[25], the cited page number is correcte

\mu-\tau Symmetry and Maximal CP Violation

We argue the possibility that a real part of a flavor neutrino mass matrix only respects a mu-tau symmetry. This possibility is shown to be extended to more general case with a phase parameter \theta, where the mu-tau symmetric part has a phase of \theta/2. This texture shows maximal CP violation and no Majorana CP violation.Comment: 5 pages, version to appear in Phys. Lett.

Determination of Neutrino Mass Texture for Maximal CP Violation

We show a general form of neutrino mass matrix (M), whose matrix elements are denoted by M_{ij} (i.j=e, mu, tau) as flavor neutrino masses, that induces maximal CP violation as well as maximal atmospheric neutrino mixing. The masses of M_{mu mu}, M_{tau tau} and M_{mu tau}+sigma M_{ee} (sigma =\pm 1) turn out to be completely determined by M_{e mu} and M_{e tau} for given mixing angles. The appearance of CP violation is found to originate from the interference between the mu-tau symmetric part of M and its breaking part. If |M_{e mu}|=|M_{e tau}|, giving either M_{e mu}=-sigma e^{i theta} M_{e tau} or M_{e mu}=-sigma e^{i theta}M*_{e tau} with a phase parameter theta, is further imposed, we find that |M_{mu mu}|=|M_{tau tau}|is also satisfied. These two constraints can be regarded as an extended version of the constraints in the mu-tau symmetric texture given by M_{e mu}=-sigma M_{e tau} and M_{mu mu}=M_{tau tau}. Majorana CP violation becomes active if arg(M_{mu tau})\neq arg(M_{e mu})+theta/2 for M_{e mu}=-sigma e^{i theta} M_{e tau} and if arg(M_{mu tau})\neq theta/2 for M_{e mu}=-sigma e^{i theta} M*_{e tau}.Comment: 10 pages, RevTex, typos corrected, minor clarifications added in Sec.3 and Sec.4, version to appear in Nucl. Phys.

The Interplay between Neutrinos and Charged Leptons in the Minimal SU(3)_LxU(1)_N Gauge Model

In the minimal SU(3)_LxU(1)_N gauge model with a global L_e-L_mu-L_tau (=L') symmetry and a discrete Z_4 symmetry, it is found that the interplay between neutrinos and charged leptons contained in triplets of \psi^i=(\nu^i_L, \ell^i_L, \ell^{ci}_L) (i=1,2,3) naturally leads to the large mixing angle (LMA) MSW solution. The model includes two (anti)sextet Higgs scalars, S^(0) with L'=0 and S^(+) with L'=2, which, respectively, couple to \psi^1\psi^{2,3} for the electron mass and masses of atmospheric neutrinos and to \psi^{2,3}\psi^{2,3} for the \mu- and \tau-masses and one-loop radiative neutrino masses relevant to solar neutrinos. This mechanism is realized by utilizing an additional residual discrete symmetry supplied by explicitly broken L', which guarantees the absence of tree-level neutrino mass terms of the \psi^{2,3}\psi^{2,3}-type. Pure rotation effects due to the diagonalization of neutrino and charged-lepton mass matrices are estimated to yield \Delta m^2_\odot/\Delta m^2_{atm} \leq (m_e/m_\mu)^{3/2}=O(10^{-4}) but the radiative effects supersede the rotation effects to yield \Delta m^2_\odot/\Delta m^2_{atm}=O(10^{-2}) as the LMA solution.Comment: 16 pages, RevTeX, including 2 figures with typos and misprints corrected and with modifications in sections II-B and V, accepted by Nuclear Physics