2,584 research outputs found

    Anapole Moment and Other Constraints on the Strangeness Conserving Hadronic Weak Interaction

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    Standard analyses of low-energy NN and nuclear parity-violating observables have been based on a pi-, rho-, and omega-exchange model capable of describing all five independent s-p partial waves. Here a parallel analysis is performed for the one-body, exchange-current, and nuclear polarization contributions to the anapole moments of 133Cs and 205Tl. The resulting constraints are not consistent, though there remains some degree of uncertainty in the nuclear structure analysis of the atomic moments.Comment: Revtex, 10 pages, 1 figur

    Precision Study of Positronium: Testing Bound State QED Theory

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    As an unstable light pure leptonic system, positronium is a very specific probe atom to test bound state QED. In contrast to ordinary QED for free leptons, the bound state QED theory is not so well understood and bound state approaches deserve highly accurate tests. We present a brief overview of precision studies of positronium paying special attention to uncertainties of theory as well as comparison of theory and experiment. We also consider in detail advantages and disadvantages of positronium tests compared to other QED experiments.Comment: A talk presented at Workshop on Positronium Physics (ETH Zurich, May 30-31, 2003

    Manifestation of the Nuclear Anapole Moment in M1 Transitions in Thallium

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    We calculate nuclear spin-dependent parity non-conserving E1E1-amplitudes for optical transition 6p1/2,F−>6p3/2,Fâ€Č6p_{1/2,F} -> 6p_{3/2,F'} and for hyperfine transition 6p1/2,F−>6p1/2,Fâ€Č6p_{1/2,F} -> 6p_{1/2,F'} in Tl. Experimental limit on the former amplitude placed by Vetter et al. [PRL, 74, 2658 (1995)] corresponds to the anapole moment constant Îșa=−0.26±0.27\kappa_a = -0.26 \pm 0.27. Experiment on the hyperfine transition can give direct measurement of the spin-dependent amplitude, because spin-independent amplitude turns to zero.Comment: 4 pages, LaTeX2e, uses revtex4.cl

    Negative group delay for Dirac particles traveling through a potential well

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    The properties of group delay for Dirac particles traveling through a potential well are investigated. A necessary condition is put forward for the group delay to be negative. It is shown that this negative group delay is closely related to its anomalous dependence on the width of the potential well. In order to demonstrate the validity of stationary-phase approach, numerical simulations are made for Gaussian-shaped temporal wave packets. A restriction to the potential-well's width is obtained that is necessary for the wave packet to remain distortionless in the travelling. Numerical comparison shows that the relativistic group delay is larger than its corresponding non-relativistic one.Comment: 10 pages, 5 figure

    Vlasov Description Of Dense Quark Matter

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    We discuss properties of quark matter at finite baryon densities and zero temperature in a Vlasov approach. We use a screened interquark Richardson's potential consistent with the indications of Lattice QCD calculations. We analyze the choices of the quark masses and the parameters entering the potential which reproduce the binding energy (B.E.) of infinite nuclear matter. There is a transition from nuclear to quark matter at densities 5 times above normal nuclear matter density. The transition could be revealed from the determination of the position of the shifted meson masses in dense baryonic matter. A scaling form of the meson masses in dense matter is given.Comment: 15 pages 4 figure

    Atomic Parity Violation and Precision Electroweak Physics - An Updated Analysis

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    A new analysis of parity violation in atomic cesium has led to the improved value of the weak charge, QW(Cs)=−72.06±0.46Q_W({\rm Cs}) = -72.06 \pm 0.46. The implications of this result for constraining the Peskin-Takeuchi parameters S and T and for guiding searches for new Z bosons are discussed.Comment: 8 pages, LaTeX, 3 figures, Submitted to Physical Review D. Updated experimental inputs and references; clarification of notatio

    Coherent amplification of classical pion fields during the cooling of droplets of quark plasma

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    In the framework of the linear sigma model, we study the time evolution of a system of classical σ\sigma and pion fields coupled to quarks. For this purpose we solve numerically the classical transport equation for relativistic quarks coupled to the nonlinear Klein-Gordon equations for the meson fields. We examine evolution starting from variety of initial conditions corresponding to spherical droplets of hot quark matter, which might mimic the behaviour of a quark plasma produced in high-energy nucleus-nucleus collisions. For large droplets we find a strong amplification of the pion field that oscillates in time. This leads to a coherent production of pions with a particular isospin and so would have similar observable effects to a disoriented chiral condensate which various authors have suggested might be a signal of the chiral phase transition. The mechanism for amplification of the pion field found here does not rely on this phase transition and is better thought of as a "pion laser" which is driven by large oscillations of the σ\sigma field.Comment: 12 TeX pages + 20 postscript figures, psfig styl

    Radium ion: A possible candidate for measuring atomic parity violation

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    Single trapped and laser cooled Radium ion as a possible candidate for measuring the parity violation induced frequency shift has been discussed here. Even though the technique to be used is similar to that proposed by Fortson [1], Radium has its own advantages and disadvantages. The most attractive part of Radium ion as compared to that of Barium ion is its mass which comes along with added complexity of instability as well as other issues which are discussed hereComment: Conference proceedin

    Role of Present and Future Atomic Parity Violation Experiments in Precision Electroweak Tests

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    Recent reanalyses of the atomic physics effects on the weak charge in cesium have led to a value in much closer agreement with predictions of the Standard Model. We review precision electroweak tests, their implications for upper bounds on the mass of the Higgs boson, possible ways in which these bounds may be circumvented, and the requirements placed upon accuracy of future atomic parity violation experiments by these considerations.Comment: 10 pages, LaTeX, 1 figure, to be submitted to Physical Review D, new data on neutrino deep inelastic scattering include

    Analgesic Effects of GpTx-1, PF-04856264 and CNV1014802 in a Mouse Model of NaV1.7-Mediated Pain

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    Loss-of-function mutations of NaV1.7 lead to congenital insensitivity to pain, a rare condition resulting in individuals who are otherwise normal except for the inability to sense pain, making pharmacological inhibition of NaV1.7 a promising therapeutic strategy for the treatment of pain. We characterized a novel mouse model of NaV1.7-mediated pain based on intraplantar injection of the scorpion toxin OD1, which is suitable for rapid in vivo profiling of NaV1.7 inhibitors. Intraplantar injection of OD1 caused spontaneous pain behaviors, which were reversed by co-injection with NaV1.7 inhibitors and significantly reduced in NaV1.7−/− mice. To validate the use of the model for profiling NaV1.7 inhibitors, we determined the NaV selectivity and tested the efficacy of the reported NaV1.7 inhibitors GpTx-1, PF-04856264 and CNV1014802 (raxatrigine). GpTx-1 selectively inhibited NaV1.7 and was effective when co-administered with OD1, but lacked efficacy when delivered systemically. PF-04856264 state-dependently and selectively inhibited NaV1.7 and significantly reduced OD1-induced spontaneous pain when delivered locally and systemically. CNV1014802 state-dependently, but non-selectively, inhibited NaV channels and was only effective in the OD1 model when delivered systemically. Our novel model of NaV1.7-mediated pain based on intraplantar injection of OD1 is thus suitable for the rapid in vivo characterization of the analgesic efficacy of NaV1.7 inhibitors
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