2,822 research outputs found

    New Source of CP violation in B physics ?

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    In this talk we discuss how the down type left-right squark mixing in Supersymmetry can induce a new source of CP violation in the time dependent asymmtries in B --> phi K process. We use QCD improved factorization process to calculate the hadronic matrix element for the process and find the allowed parameter space for ρ\rho and ϕ\phi , the magnitude and phase of the down type LR(RL) squark mixing parameter δLR(RL)bs\delta^{bs}_{LR(RL)}. In the same allowed regin we calculate the expected CP asymmtries in the BϕKB \to \phi K^{*} process.Comment: 16 pages, Latex, 2 postscript figures, invited talk presented by N.G. Deshpande at the 9th Adriatic meeting, Dubrovnik, Croatia, 4-14 September, 2003. With updated reference

    Science results from the imaging Fourier transform spectrometer SpIOMM

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    SpIOMM is an imaging Fourier transform spectrometer designed to obtain the visible range (350 to 850 nm) spectrum of every light source in a circular field of view of 12 arcminutes in diameter. It is attached to the 1.6-m telescope of the Observatoire du Mont Megantic in southern Quebec. We present here some results of three successful observing runs in 2007, which highlight SpIOMMs capabilities to map emission line objects over a very wide field of view and a broad spectral range. In particular, we discuss data cubes from the planetary nebula M27, the supernova remnants NGC 6992 and M1, the barred spiral galaxy NGC7479, as well as Stephans quintet, an interacting group of galaxies.Comment: 10 pages, 7 figures, to appear in "Ground-based and Airborne Instrumentation for Astronomy II", SPIE conference, Marseille, 23-28 June 200

    Determination of quark-antiquark component of the photon wave function for u, d, s quarks

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    Based on the data for the transitions pi0, eta, eta' -> gamma gamma^*(Q^2) and reactions of the e^+ e^- -annihilations, e^+ e^- -> rho0, omega, phi and e^+ e^--> hadrons at 1<E_{e^+e^-}<3.7 GeV, we determine the light-quark components of the photon wave function gamma^*(Q^2) -> q anti-q (q= u, d, s) for the region 0< Q^2 <1 (GeV/c)^2.Comment: 17 pages, some typos correcte

    Evidence of symptom profiles consistent with posttraumatic stress disorder and complex posttraumatic stress disorder in different trauma samples

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    Background: The International Classification of Diseases, 11th version (ICD-11), proposes two related stress and trauma-related disorders, posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD). A diagnosis of CPTSD requires that in addition to the PTSD symptoms, an individual must also endorse symptoms in three major domains: (1) affective dysregulation, (2) negative self-concepts, and (3) interpersonal problems. This study aimed to determine if the naturally occurring distribution of symptoms in three groups of traumatised individuals (bereavement, sexual victimisation, and physical assault) were consistent with the ICD-11, PTSD, and CPTSD specification. The study also investigated whether these groups differed on a range of other psychological problems. Methods and Results: Participants completed self-report measures of each symptom group and latent class analyses consistently found that a three class solution was best. The classes were “PTSD only,” “CPTSD,” and “low PTSD/CPTSD.” These classes differed significantly on measures of depression, anxiety, dissociation, sleep disturbances, somatisation, interpersonal sensitivity, and aggression. The “CPTSD” class in the three samples scored highest on all the variables, with the “PTSD only” class scoring lower and the “low PTSD/CPTSD” class the lowest. Conclusion: This study provides evidence to support the diagnostic structure of CPTSD and indicted that CPTSD is associated with a broad range of other psychological problems

    Binary systems of neutral mesons in Quantum Field Theory

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    Quasi-degenerate binary systems of neutral mesons of the kaon type are investigated in Quantum Field Theory (QFT). General constraints cast by analyticity and discrete symmetries P, C, CP, TCP on the propagator (and on its spectral function) are deduced. Its poles are the physical masses; this unambiguously defines the propagating eigenstates. It is diagonalized and its spectrum thoroughly investigated. The role of ``spurious'' states, of zero norm at the poles, is emphasized, in particular for unitarity and for the realization of TCP symmetry. The K_L-K_S mass splitting triggers a tiny difference between their CP violating parameters \epsilon_L and \epsilon_S, without any violation of TCP. A constant mass matrix like used in Quantum Mechanics (QM) can only be introduced in a linear approximation to the inverse propagator, which respects its analyticity and positivity properties; it is however unable to faithfully describe all features of neutral mesons as we determine them in QFT, nor to provide any sensible parameterization of eventual effects of TCP violation. The suitable way to diagonalize the propagator makes use of a bi-orthogonal basis; it is inequivalent to a bi-unitary transformation (unless the propagator is normal, which cannot occur here). Problems linked with the existence of different ``in'' and ``out'' eigenstates are smoothed out. We study phenomenological consequences of the differences between the QFT and QM treatments. The non-vanishing of semi-leptonic asymmetry \delta_S - \delta_L does not signal, unlike usually claimed, TCP violation, while A_TCP keeps vanishing when TCP is realized. We provide expressions invariant by the rephasing of K0 and K0bar.Comment: 44 pages, 2 figures. Version to appear in Int. J. Mod. Phys.

    Prospects for Pentaquark Searches in e+ee^+e^- Annihilations and γγ\gamma\gamma Collisions

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    Recent strong experimental evidence of a narrow exotic S = +1 baryon resonance, Θ+\Theta^+, suggests the existence of other exotic baryons. We discuss the prospects of confirming earlier experimental evidence of Θ+\Theta^+ and the observation of additional hypothetical exotic baryons in e+ee^+e^- annihilations and γγ\gamma\gamma collisions at LEP and B Factories

    Precision measurement of the branching fractions of J/psi -> pi+pi-pi0 and psi' -> pi+pi-pi0

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    We study the decays of the J/psi and psi' mesons to pi+pi-pi0 using data samples at both resonances collected with the BES III detector in 2009. We measure the corresponding branching fractions with unprecedented precision and provide mass spectra and Dalitz plots. The branching fraction for J/psi -> pi+pi-pi0 is determined to be (2.137 +- 0.004 (stat.) +0.058-0.056 (syst.) +0.027-0.026 (norm.))*10-2, and the branching fraction for psi' -> pi+pi-pi0 is measured as (2.14 +- 0.03 (stat.) +0.08-0.07 (syst.) +0.09-0.08 (norm.))*10-4. The J/psi decay is found to be dominated by an intermediate rho(770) state, whereas the psi' decay is dominated by di-pion masses around 2.2 GeV/c2, leading to strikingly different Dalitz distributions.Comment: 15 pages, 2 figure

    Testing QCD factorisation and charming penguins in charmless BPV{\boldsymbol{B\to PV}}

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    We try a global fit of the experimental branching ratios and CP-asymmetries of the charmless BPVB\to PV decays according to QCD factorisation. We find it impossible to reach a satisfactory agreement, the confidence level (CL) of the best fit is smaller than .1 %. The main reason for this failure is the difficulty to accomodate several large experimental branching ratios of the strange channels. Furthermore, experiment was not able to exclude a large direct CP asymmetry in B0ˉρ+π\bar {B^0}\to\rho^+ \pi^-, which is predicted very small by QCD factorisation. Trying a fit with QCD factorisation complemented by a charming-penguin inspired model we reach a best fit which is not excluded by experiment (CL of about 8 %) but is not fully convincing. These negative results must be tempered by the remark that some of the experimental data used are recent and might still evolve significantly.Comment: 21 pages, 4 figures; several typos corrected, added one footnote and two references, comments added about PQCD. To appear in Phys.Rev.

    Study of J/ψppˉJ/\psi\to p\bar{p} and J/ψnnˉJ/\psi\to n\bar{n}

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    The decays J/ψppˉJ/\psi\to p\bar{p} and J/ψnnˉJ/\psi\to n\bar{n} have been investigated with a sample of 225.2 million J/ψJ/\psi events collected with the BESIII detector at the BEPCII e+ee^+e^- collider. The branching fractions are determined to be B(J/ψppˉ)=(2.112±0.004±0.031)×103\mathcal{B}(J/\psi\to p\bar{p})=(2.112\pm0.004\pm0.031)\times10^{-3} and B(J/ψnnˉ)=(2.07±0.01±0.17)×103\mathcal{B}(J/\psi\to n\bar{n})=(2.07\pm0.01\pm0.17)\times10^{-3}. Distributions of the angle θ\theta between the proton or anti-neutron and the beam direction are well described by the form 1+αcos2θ1+\alpha\cos^2\theta, and we find α=0.595±0.012±0.015\alpha=0.595\pm0.012\pm0.015 for J/ψppˉJ/\psi\to p\bar{p} and α=0.50±0.04±0.21\alpha=0.50\pm0.04\pm0.21 for J/ψnnˉJ/\psi\to n\bar{n}. Our branching-fraction results suggest a large phase angle between the strong and electromagnetic amplitudes describing the J/ψNNˉJ/\psi\to N\bar{N} decay.Comment: 16 pages, 13 figures, the 2nd version, submitted to PR
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