Invariant approach to flavour-dependent CP-violating phases in the MSSM

We use a new weak basis invariant approach to classify all the observable phases in any extension of the Standard Model (SM). We apply this formalism to determine the invariant CP phases in a simplified version of the Minimal Supersymmetric SM with only three non-trivial flavour structures. We propose four experimental measures to fix completely all the observable phases in the model. After these phases have been determined from experiment, we are able to make predictions on any other CP-violating observable in the theory, much in the same way as in the Standard Model all CP-violation observables are proportional to the Jarlskog invariant.Comment: 25 pages, 12 figure

Tree-level flavor-changing neutral currents in the B system: From CP asymmetries to rare decays

Tree-level flavor-changing neutral currents (FCNC) are characteristic of models with extra vectorlike quarks. These new couplings can strongly modify the B/sup 0/ CP asymmetries without conflicting with low-energy constraints. In the light of low CP asymmetry in B to J/ psi K/sub S/, we discuss the implications of these contributions. We find that even these low values can be easily accommodated in these models. Furthermore, we show that the new data from B factories tend to favor an O(20) enhancement of the b to dll transition over the SM expectation. (25 refs)

A Geometric Approach Towards Momentum Conservation

In this work, a geometric discretization of the Navier-Stokes equations is sought by treating momentum as a covector-valued volume-form. The novelty of this approach is that we treat conservation of momentum as a tensor equation and describe a higher order approximation to this tensor equation. The resulting scheme satisfies mass and momentum conservation laws exactly, and resembles a staggered-mesh finite-volume method. Numerical test-cases to which the discretization scheme is applied are the Kovasznay flow, and lid-driven cavity flow

How sensitive to FCNC can B0B^0 CP asymmetries be?

We show that the study of CP asymmetries in neutral B-meson decays provides a very sensitive probe of flavour-changing neutral currents (FCNC). We introduce two new angles, $\alpha_{SM}$ and $\beta_{SM}$, whose main feature is that they can be readily obtained from the measurement of the CP asymmetries $a_{J/\psi K_s}$, $a_{\pi^+ \pi^-}$ and the ratio $R_u \equiv|V_{ud}V_{ub}^*|/|V_{cd}V_{cb}^*|$, providing a quantitative test of the presence of new physics in a model-independent way. Assuming that new physics is due to the presence of an isosinglet down-type quark, we indicate how to reconstruct the unitarity quadrangles and point out that the measurements of the above asymmetries, within the expected experimental errors, may detect FCNC effects, even for values of $|\sum_{i=1}^3 V_{id} V_{ib}^* / (V_{td} V_{tb}^*)|$ at the level of a few times $10^{-2}$.Comment: 19 pages including 9 figure

γ\gamma - Z interferometry at a Φ\Phi-factory

We analyze the possibilities that the proposed $\Phi$-factories offer to measure $\gamma-Z$ interference. In the unpolarized beam case, we study different signatures in the $\rho \pi$ channel, taking advantage of the presence of the near-by $a_1$ resonance. We build a C-odd forward-backward asymmetry, estimated to be around $10^{-5}$, and (P-even, T-even) and (P-odd, T-odd) alignments of the $\rho$, to be seen from the angular distribution of its $\pi \pi$ decay products. With polarized electrons a left-right asymmetry around $2\times 10^{-4}$ is present in all channels. At leading order this asymmetry is independent of hadronic matrix elements and is sensitive to the $Z^0-s\bar{s}$ vector coupling. In the $\rho \pi$ channel, a combined left-right forward-backward asymmetry is considered.Comment: 29 pages + 6 figures. Some changes concerning $a_1$ observables, especially related with possible 2 $\gamma$ contribution

Fine Grid Numerical Solutions of Triangular Cavity Flow

Numerical solutions of 2-D steady incompressible flow inside a triangular cavity are presented. For the purpose of comparing our results with several different triangular cavity studies with different triangle geometries, a general triangle mapped onto a computational domain is considered. The Navier-Stokes equations in general curvilinear coordinates in streamfunction and vorticity formulation are numerically solved. Using a very fine grid mesh, the triangular cavity flow is solved for high Reynolds numbers. The results are compared with the numerical solutions found in the literature and also with analytical solutions as well. Detailed results are presented

Somatic embryogenesis and plant regeneration of Vitis vinifera cultivars 'Macabeo' and 'Tempranillo'

Different experimental conditions have been compared to achieve a high efficiency in embryogenic calli initiation from 'Macabeo' and 'Tempranillo' anthers. Specifically, two stages of anther development were tested (corresponding to tetrad cells or uninucleate pollen), and direct culture of anthers was compared to culture after a cold treatment of inflorescences (4 °C during 48 h). In addition, two induction media (C1 P and B2), mainly differing by microelement and cytokinin levels, were evaluated. Experiment repeatability was also examined with a repetition of anther culture one week later. Callus initiation was similar in all media and treatments for both cultivars, usually starting from the anther filament. A simple protocol for efficient induction of embryogenesis in 'Macabeo' and 'Tempranillo' consisted in:selecting the first inflorescence from hardwood cutting,excising anthers at uninucleate pollen stage without cold treatment of the inflorescences,incubating anthers on C1 P medium.The procedure used for embryo germination and plant regeneration, allowed to obtain a conversion rate up to 75 % in 'Macabeo' and 60 % in 'Tempranillo'. The protocol proposed represents the first regeneration system developed for the Spanish cultivars 'Macabeo' and 'Tempranillo'.

Efecto de posibles mitovirus en el crecimiento in vitro de aislados de Gremmeniella abietina bajo diferentes condiciones de laboratorio

Mitoviruses have been found in several forest pathogens (i.e. Cryphonectria parasitica, Gremmeniella abietina), and because they have been shown to reduce the virulence of host fungi there is a growing interest in studying their use as a biocontrol. This study was carried out to test the effect of temperature (5°C, 15°C, 25°C and 35°C), pH (4, 5, 7 and 9) and osmotic potential (–0.6, –1.2, –1.8 and –2.4 MPa) on the mycelial growth of seven G. abietina isolates under controlled laboratory conditions. Four of the isolates hosted mitoviruses and three of them did not. During the experiment, mycelial growth was recorded every week for a period of 8 weeks. Results showed no differences in growth behavior between mitovirus infected and non-infected isolates when placed under different pH modifications. However, the mitovirus-infected isolates presented larger mycelial growth than the mitovirus-free ones when at the fungi’s optimal growing temperature of 15°C. When growing at certain osmotic potentials (–0.6 and –1.8 MPa) a reduction in growth of the mitovirus-infected isolates was observed. The results of this experiment suggest that mycelial growth among non-infected isolates and isolates naturally infected by mitovirus vary under different culture conditions, thus providing further insight into the effects of mitovirus on Gremmeniella abietina isolates.Los mitovirus son virus exclusivamente fúngicos que han sido aislados de algunos patógenos forestales (i.e. Cryphonectria parasitica, Gremmeniella abietina) y ya que pueden reducir la virulencia del hongo existe un creciente interés por su posible papel como agentes de control biológico. Se ha llevado a cabo un estudio para evaluar el efecto de la temperatura (5°C, 15°C, 25°C y 35°C), el pH (4, 5, 7 y 9) y el potencial osmótico (–0.6, –1.2, –1.8, –2.4 MPa) en el crecimiento micelial de siete aislados de G. abietina bajo condiciones controladas de laboratorio. Cuatro de los aislados albergaban mitovirus y tres de ellos no. Durante el experimento, el crecimiento micelial fue registrado semanalmente hasta completar 8 mediciones. Los aislados infectados con mitovirus presentaron mayor crecimiento micelial que los no infectados a la temperatura de crecimiento óptimo del hongo de 15°C. No se observaron efectos de la presencia de mitovirus entre los aislados infectados y los no infectados en los tratamientos de modificación del pH. Cuando se modificaron los potenciales osmóticos se observó una reducción del crecimiento micelial de los aislados infectados con mitovirus en los potenciales osmóticos de –0.6 y –1.8 MPa. Los resultados de este experimento sugieren que la presencia de los mitovirus afecta al crecimiento micelial del hongo bajo distintas condiciones de laboratorio. Este estudio proporciona un conocimiento más profundo de los efectos de las infecciones víricas en aislados españoles de Gremmeniella abietina

Thermal Response Measurement and Performance Evaluation of Borehole Heat Exchangers: A Case Study in Kazakhstan

The purpose of the present work was to determine the thermal performance of borehole heat exchangers, considering the influences of their geometric configurations and the thermophysical properties of the soil, grout and pipe wall material. A three-dimensional model was developed for the heat and mass transfer in soil (a porous medium) and grout, together with one-dimensional conductive heat transfer through the pipe walls and one-dimensional convective heat transfer of the heat transfer fluid circulating in the pipes. An algorithm was developed to solve the mathematical equations of the model. The COMSOL Multiphysics software was used to implement the algorithm and perform the numerical simulations. An apparatus was designed, installed and tested to implement the thermal response test (TRT) method. Two wells of depth 50 m were drilled in the Almaty region in Kazakhstan. Gravel and till/loam were mainly found, which are in accordance with the stratigraphic map of the local geological data. In each well, two borehole heat exchangers were installed, which were an integral part of the ground source heat pump. The TRT measurements were conducted using one borehole heat exchanger in one well and the data were obtained. The present TRT data were found to be in good agreement with those available in literature. The numerical results of the model agreed well with the present TRT data, with the root-mean-square-deviation within 0.184 °C. The TRT data, together with the predictions of the line-source analytical model, were utilized to determine the soil thermal conductivity (λg = 2.35 W/m K) and the thermal resistance of the borehole heat exchanger from the heat transfer fluid to the soil (Rb = 0.20 m K/W). The model was then used to predict the efficiencies of the borehole heat exchangers with various geometric configurations and dimensions. The simulation results show that the spiral borehole heat exchanger extracts the highest amount of heat, followed by the multi-tube, double U-type parallel, double U-type cross and single U-type. It is also found that the spiral configuration can save 34.6% drilling depth compared with the conventional single U-type one, suggesting that the spiral configuration is the best one in terms of the depth and the maximum heat extracted. The simulation results showed that (i) more heat was extracted with a higher thermal conductivity of grout material, in the range of 0.5–3.3 W/m K; (ii) the extracted heat remained unchanged for a thermal conductivity of pipe material higher than 2.0 W/m K (experiments in the range of 0.24–0.42 W/m K); (iii) the extracted heat remained unchanged for a volumetric flow rate of water higher than 1.0 m3/h (experimental flow rate 0.6 m3/h); and (iv) the heat extracted by the borehole heat exchanger increased with an increase in the thermal conductivity of the soil (experiments in the range of 0.4–6.0 W/m K). The numerical tool developed, the TRT data and simulation results obtained from the present work are of great value for design and optimization of borehole heat exchangers as well as studying other important factors such as the heat transfer performance during charging/discharging, freezing factor and thermal interference