78,329 research outputs found

    Profiles of the Unitarity Triangle and CP-Violating Phases in the Standard Model and Supersymmetric Theories

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    We report on a comparative study of the profile of the CKM unitarity triangle, and the resulting CP asymmetries in B decays, in the standard model and in several variants of the minimal supersymmetric standard model (MSSM), characterized by a single phase in the quark flavour mixing matrix. The supersymmetric contributions to the mass differences \Delta M_d, \Delta M_s and to the CP-violating quantity |\epsilon| are, to an excellent approximation, equal to each other in these theories, allowing for a particularly simple way of implementing the resulting constraints on the elements of V_{CKM} from the present knowledge of these quantities. Incorporating the next-to-leading-order corrections and applying the current direct and indirect constraints on the supersymmetric parameters, we find that the predicted ranges of \sin 2 \beta in the standard model and in MSSM models are very similar. However, precise measurements at B-factories and hadron machines may be able to distinguish these theories in terms of the other two CP-violating phases \alpha and \gamma. This is illustrated for some representative values of the supersymmetric contributions in \Delta M_d, \Delta M_s and |\epsilon|.Comment: 30 pages, 9 figures; typos corrected, minor notation change; matches version to appear in the European Physical Journal

    Attainable lengths for circular binary words avoiding k-powers

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    We show that binary circular words of length n avoiding 7/3+ powers exist for every sufficiently large n. This is not the case for binary circular words avoiding k+ powers with k < 7/3https://projecteuclid.org/download/pdf_1/euclid.bbms/113379334

    A system-on-chip digital pH meter for use in a wireless diagnostic capsule

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    This paper describes the design and implementation of a system-on-chip digital pH meter, for use in a wireless capsule application. The system is organized around an 8-bit microcontroller, designed to be functionally identical to the Motorola 6805. The analog subsystem contains a floating-electrode ISFET, which is fully compatible with a commercial CMOS process. On-chip programmable voltage references and multiplexors permit flexibility with the minimum of external connections. The chip is designed in a modular fashion to facilitate verification and component re-use. The single-chip pH meter can be directly connected to a personal computer, and gives a response of 37 bits/pH, within an operating range of 7 pH units

    Design of a single-chip pH sensor using a conventional 0.6-&#956;m CMOS process

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    A pH sensor fabricated on a single chip by an unmodified, commercial 0.6-/spl &#956;m CMOS process is presented. The sensor comprises a circuit for making differential measurements between an ion-sensitive field-effect transistor (ISFET) and a reference FET (REFET). The ISFET has a floating-gate structure and uses the silicon nitride passivation layer as a pH-sensitive insulator. As fabricated, it has a large threshold voltage that is postulated to be caused by a trapped charge on the floating gate. Ultraviolet radiation and bulk-substrate biasing is used to permanently modify the threshold voltage so that the ISFET can be used in a battery-operated circuit. A novel post-processing method using a single layer of photoresist is used to define the sensing areas and to provide robust encapsulation for the chip. The complete circuit, operating from a single 3-V supply, provides an output voltage proportional to pH and can be powered down when not required

    Energy of Stable Half-Quantum Vortex in Equal-Spin-Pairing

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    In the triplet equal-spin-pairing states of both 3He-A phase and Sr2RuO4 superconductor, existence of Half-Quantum Vortices HQVs are possible. The vortices carry half-integer multiples of magnetic quantum flux (hc/2e). To obtain equilibrium condition for such systems, one has to take into account not only weak interaction energy but also effects of Landau Fermi liquid. Our method is based on the explanation of the HQV in terms of a BCS-like wave function with a spin-dependent boots. We have considered l=2 order effects of the Landau Fermi liquid. We have shown that the effects of Landau Fermi liquid interaction with l=2 are negligible. In stable HQV, an effective Zeeman field exists. In the thermodynamic stability state, the effective Zeeman field produces a non-zero spin polarization in addition to the polarization of external magnetic field

    Effects of heavy Majorana neutrinos at lepton-proton colliders

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    We discuss the prospects of detecting the processes e+pνˉe++Xe^+p\to\bar\nu_e\ell^+\ell'^+X and νepe++X\nu_ep\to e\ell^+\ell'^+X (,=e,μ,τ\ell,\ell'=e,\mu,\tau) under the conditions of the present epep collider HERA and of future colliders. These high-energy processes are assumed to be mediated by the exchange of heavy Majorana neutrinos (HMN). We consider two simple scenarios for the HMN mass spectrum: the effective singlet (m1m2<m3...m_1\ll m_2<m_3...) and the effective doublet (m1<m2m3...m_1<m_2\ll m_3...). For the latter case, the cross section includes information about CP-violating phases.Comment: 5pages, 2 figures; published in conference proceedings: Particle Physics in Laboratory, Space and Universe, 11th. Lomonosov Conf. on Elementary Particle Physics (Moscow, 21-27 August 2003) (Singapore, World Scientific, 2005

    Electron angular correlation in neutrinoless double beta decay and new physics

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    The angular correlation of the electrons in the neutrinoless double beta decay (0ν2β0\nu2\beta) is calculated taking into account the nucleon recoil, the SS and PP-waves for the electrons and the electron mass using a general Lorentz invariant effective Lagrangian. We show that the angular coefficient is essentially independent of the nuclear matrix element models. We work out the angular coefficient in several scenarios for new physics, in particular, in the left-right symmetric models.Comment: 5 pages, 1 figure; to appear in the Proceedings of the 13th Lomonosov Conference on Elementary Particle Physics, 23 --29 August 2007, Moscow, Russi
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