59,782 research outputs found

    Exact Quantum States for all Two-Dimensional Dilaton Gravity Theories

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    It is shown that the recently obtained quantum wave functionals in terms of the CJZ variables for generic 2d dilaton gravity are equivalent to the previously reported exact quantum wave functionals in geometrical variables. A third representation of these exact quantum states is also presented

    Black hole mass estimates in quasars - A comparative analysis of high- and low-ionization lines

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    The inter-line comparison between high- and low-ionization emission lines has yielded a wealth of information on the quasar broad line region (BLR) structure and dynamics, including perhaps the earliest unambiguous evidence in favor of a disk + wind structure in radio-quiet quasars. We carried out an analysis of the CIV 1549 and Hbeta line profiles of 28 Hamburg-ESO high luminosity quasars and of 48 low-z, low luminosity sources in order to test whether the high-ionization line CIV 1549 width could be correlated with Hbeta and be used as a virial broadening estimator. We analyze intermediate- to high-S/N, moderate resolution optical and NIR spectra covering the redshifted CIV and Hβ\beta over a broad range of luminosity log L ~ 44 - 48.5 [erg/s] and redshift (0 - 3), following an approach based on the quasar main sequence. The present analysis indicates that the line width of CIV 1549 is not immediately offering a virial broadening estimator equivalent to Hβ\beta. At the same time a virialized part of the BLR appears to be preserved even at the highest luminosities. We suggest a correction to FWHM(CIV) for Eddington ratio (using the CIV blueshift as a proxy) and luminosity effects that can be applied over more than four dex in luminosity. Great care should be used in estimating high-L black hole masses from CIV 1549 line width. However, once corrected FWHM(CIV) values are used, a CIV-based scaling law can yield unbiased MBH values with respect to the ones based on Hβ\beta with sample standard deviation ~ 0.3 dex.Comment: 43 pages, 15 Figures, submitted to A&

    Modelling the exposure to Cronobacter sakazakii by consumption of a cocoa-milk-based beverage processed by pulsed electric fields

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    peer-reviewedM.C. Pina-Pérez is grateful to CSIC for providing a DOCTOR contract linked to the INNPACTO project IPT-2011-1724-060000. This study was carried out with funds from BISOSTAD project PSE-060000-2009-003, Generalitat Valenciana I+D+I emergent research groups GV/2010/064 and CYCIT project AGL2010-22206-C02-01.Infants’ exposure (Nf ) to Cronobacter sakazakii via the consumption of infant-rich-inpolyphenols cocoa-milk-based beverages (CCX-M) treated with high-intensity pulsed electric fields (PEF) was evaluated. Monte Carlo simulation enabled the prediction of the variability in C. sakazakii load in beverages at the time of consumption to be estimated. Different scenarios (initial contamination levels; PEF treatment conditions; and time-temperature combinations of CCX-M beverages storage after treatment) were simulated. Cocoa addition and PEF treatment resulted in the most influential input factors to control bacterial final load. Cronobacter spp. exposure risk was reduced by a maximum of 100 times at 95% of iterations due to addition of cocoa at 5 g/100 mL, corresponding to scenario 3 (PEF: 15 kV/cm–3,000 μs; storage 120 h at 8 °C). Moreover, the probability of illness for a healthy population was reduced from 2.15 × 10-8, in the baseline scenario, to 4.78 × 10-10 due to cocoa addition and application of 15 kV/cm–3,000 μs PEF treatment.BISOSTAD projec

    The next-to-leading order vertex for a forward jet plus a rapidity gap at high energies

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    We present the results for the calculation of the forward jet vertex associated to a rapidity gap (coupling of a hard pomeron to the jet) in the Balitsky-Fadin-Kuraev-Lipatov (BFKL) formalism at next-to-leading order (NLO). We handle the real emission contributions making use of the high energy effective action proposed by Lipatov, valid for multi-Regge and quasi-multi-Regge kinematics. This result is important since it allows, together with the NLO non-forward gluon Green function, to perform NLO studies of jet production in diffractive events (Mueller-Tang dijets, as a well-known example).Comment: 12 pages, some figure

    The luminosity function of Palomar 5 and its tidal tails

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    We present the main sequence luminosity function of the tidally disrupted globular cluster Palomar 5 and its tidal tails. For this work we analyzed imaging data obtained with the Wide Field Camera at the INT (La Palma) and data from the Wide Field Imager at the MPG/ESO 2.2 m telescope at La Silla down to a limiting magnitude of approximately 24.5 mag in B. Our results indicate that preferentially fainter stars were removed from the cluster so that the LF of the cluster's main body exhibits a significant degree of flattening compared to other GCs. This is attributed to its advanced dynamical evolution. The LF of the tails is, in turn, enhanced with faint, low-mass stars, which we interpret as a consequence of mass segregation in the cluster.Comment: 4 pages, 3 figures, to be published in the proceedings of the conference "Satellites and tidal streams" held at La Palma, Canary Islands, May 26 - 30, 200

    Three body systems with strangeness and exotic systems

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    We report on four Σ\Sigma's and three Λ\Lambda's, in the 1500 - 1800 MeV region, as two meson - one baryon S-wave (1/2)+(1/2)^+ resonances found by solving the Faddeev equations in the coupled channel approach, which can be associated to the existing SS = -1, JP=1/2+J^P= 1/2^+ low lying baryon resonances. On the other hand we also report on a new, hidden strangeness NN^* state, mostly made of KKˉNK \bar{K} N, with mass around 1920 MeV, which we think could be responsible for the peak seen in the γpK+Λ\gamma p \to K^+ \Lambda around this energy. Finally we address a very novel topic in which we show how few body systems of several ρ\rho mesons can be produced, with their spins aligned up to J=6, and how these states found theoretically can be associated to several known mesons with spins J=2,3,4,5,6.Comment: Talk at the 21st European Conference on Few Body Problems in Physics, Salamanca, Sep. 201

    Defining perturbations on submanifolds

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    We study the definition of perturbations in the presence of a submanifold, like e.g. a brane. In the standard theory of cosmological perturbations, one compares quantities at the same coordinate points in the non-perturbed and the perturbed manifolds, identified via a (non-unique) mapping between the two manifolds. In the presence of a physical submanifold one needs to modify this definition in order to evaluate perturbations of quantities at the submanifold location. As an application, we compute the perturbed metric and the extrinsic curvature tensors at the brane position in a general gauge
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