217 research outputs found

    Non local parity transformations and anomalies

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    We present an alternative derivation of the parity anomaly for a massless Dirac field in 2+1 dimensions coupled to a gauge field. The anomaly functional, a Chern-Simons action for the gauge field, is obtained from the non-trivial Jacobian corresponding to a non local symmetry of the Pauli-Villars regularized action. That Jacobian is well-defined, finite, and yields the standard Chern-Simons term when the cutoff tends to infinity.Comment: 10 pages, Latex fil

    Low frequency thermo-ultrasonication of Saccharomyces cerevisiae suspensions: Effect of temperature and of ultrasonic power

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    The combined effect of low frequency ultrasound (20 kHz) with temperature on the survival of a strain of Saccharomyces cerevisiae suspended in water was studied. The treatment temperatures tested were 45°C, 50°C and 55°C; the actual ultrasonic powers tested were 50 W, 100 W and 180 W. Application of ultrasonic waves at a non-lethal temperature did not display a deactivating action; a higher effect of ultrasound at higher temperatures was observed, and the synergy between ultrasound and temperature was confirmed. These results proved that the ultrasonic waves do not destroy the yeast’s cells; they damage them, thus increasing their sensitivity to heat. The existence of an optimal ultrasonic power for a maximal deactivating effect was shown, and was found to have a value of around 100 W (actual power)

    Fluoropyrimidine sensitivity of human MCF-7 breast cancer cells stably transfected with human uridinehosphorylase

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    The relationship between uridine phosphorylase (UP) expression level in cancer cells and the tumour sensitivity to fluoropyrimidines is unclear. In this study, we found that UP overexpression by gene transfer, and the subsequent efficient metabolic activation of 5-fluorouracil (5-FU) by the ribonucleotide pathway, does not increase the fluoropyrimidine sensitivity of MCF-7 human cancer cells. © 2001 Cancer Research Campaign http://www.bjcancer.co

    Generalized parity transformations in the regularized Chern-Simons theory

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    We study renormalization effects in the Abelian Chern-Simons (CS) action. These effects can be non-trivial when the gauge field is coupled to dynamical matter, since the regularization of the UV divergences in the model forces the introduction of a parity even piece in the gauge field action. This changes the classical (odd) transformation properties of the pure CS action. This effect, already discussed for the case of a lattice regularization by F. Berruto, M.C. Diamantini and P. Sodano in hep-th/0004203, is also present when the theory is defined in the continuum and, indeed, it is a manifestation of a more general `anomalous' effect, since it happens for every regularization scheme. We explore the physical consequences of this anomaly. We also show that generalized, nonlocal parity transformations can be defined in such a way that the regularized theory is odd, and that those transformations tend to the usual ones when the cutoff is removed. These generalized transformations play a role that is tantamount to the deformed symmetry corresponding to Ginsparg-Wilson fermions [2] (in an even number of spacetime dimensions).Comment: 16 pages, LaTeX, references added and typos correcte

    Nonlocal parity transformations and anomalies

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    We present an alternative derivation of the parity anomaly for a massless Dirac field in 2+1 dimensions coupled to a gauge field. The anomaly functional, a Chern-Simons action for the gauge field, is obtained from the non-trivial Jacobian corresponding to a non local symmetry of the Pauli-Villars regularized action. That Jacobian is well-defined, finite, and yields the standard Chern-Simons term when the cutoff tends to infinity.Facultad de Ciencias Exacta

    SANC integrator in the progress: QCD and EW contributions

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    Modules and packages for the one-loop calculations at partonic level represent the first level of SANC output computer product. The next level represents Monte Carlo integrator mcsanc, realizing fully differential hadron level calculations (convolution with PDF) for the HEP processes at LHC. In this paper we describe the implementation into the framework mcsanc first set of processes: DY NC, DY CC, ff->HW(Z) and single top production. Both EW and QCD NLO corrections are taken into account. A comparison of SANC results with those existing in the world literature is given

    Properties of 125 GeV Higgs boson in non-decoupling MSSM scenarios

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    Tantalizing hints of the Higgs boson of mass around 125 GeV have been reported at the LHC. We explore the MSSM parameter space in which the 125 GeV state is identified as the heavier of the CP even Higgs bosons, and study two scenarios where the two photon production rate can be significantly larger than the standard model (SM). In one scenario, Γ(H→γγ)\Gamma(H\to \gamma\gamma) is enhanced by a light stau contribution, while the WW∗WW^{\ast} (ZZ∗ZZ^{\ast}) rate stays around the SM rate. In the other scenario, Γ(H→bbˉ)\Gamma(H\to b\bar{b}) is suppressed and not only the γγ\gamma\gamma but also the WW∗WW^{\ast} (ZZ∗ZZ^{\ast}) rates should be enhanced. The ττˉ\tau\bar{\tau} rate can be significantly larger or smaller than the SM rate in both scenarios. Other common features of the scenarios include top quark decays into charged Higgs boson, single and pair production of all Higgs bosons in e+e−e^+e^- collisions at s≲300\sqrt{s}\lesssim 300 GeV.Comment: 20 pages, 5 figures, accepted version for publication in JHE
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