Amplitude analysis of B+→J/ψϕK+B^+\to J/\psi \phi K^+ decays

The first full amplitude analysis of $B^+\to J/\psi \phi K^+$ with $J/\psi\to\mu^+\mu^-$, $\phi\to K^+K^-$ decays is performed with a data sample of 3 fb$^{-1}$ of $pp$ collision data collected at $\sqrt{s}=7$ and $8$ TeV with the LHCb detector. The data cannot be described by a model that contains only excited kaon states decaying into $\phi K^+$, and four $J/\psi\phi$ structures are observed, each with significance over $5$ standard deviations. The quantum numbers of these structures are determined with significance of at least $4$ standard deviations. The lightest has mass consistent with, but width much larger than, previous measurements of the claimed $X(4140)$ state. The model includes significant contributions from a number of expected kaon excitations, including the first observation of the $K^{*}(1680)^+\to\phi K^+$ transition.Comment: 62 pages 26 figure

Detection of gravitational waves using a network of detectors

We formulate the data analysis problem for the detection of the Newtonian coalescing-binary signal by a network of laser interferometric gravitational wave detectors that have arbitrary orientations, but are located at the same site. We use the maximum likelihood method for optimizing the detection problem. We show that for networks comprising of up to three detectors, the optimal statistic is essentially the magnitude of the network correlation vector constructed from the matched network-filter. Alternatively, it is simply a linear combination of the signal-to-noise ratios of the individual detectors. This statistic, therefore, can be interpreted as the signal-to-noise ratio of the network. The overall sensitivity of the network is shown to increase roughly as the square-root of the number of detectors in the network. We further show that these results continue to hold even for the restricted post-Newtonian filters. Finally, our formalism is general enough to be extended to address the problem of detection of such waves from other sources by some other types of detectors, e.g., bars or spheres, or even by networks of spatially well-separated detectors.Comment: 14 pages, RevTex, 1 postscript figure. Based on talk given at Workshop on Cosmology: Observations confront theories, IIT-Kharagpur, India (January 1999

Potential of the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor for the monitoring of terrestrial chlorophyll fluorescence

Global monitoring of sun-induced chlorophyll fluorescence (SIF) is improving our knowledge about the photosynthetic functioning of terrestrial ecosystems. The feasibility of SIF retrievals from spaceborne atmospheric spectrometers has been demonstrated by a number of studies in the last years. In this work, we investigate the potential of the upcoming TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor satellite mission for SIF retrieval. TROPOMI will sample the 675–775 nm spectral window with a spectral resolution of 0.5 nm and a pixel size of 7 km × 7 km. We use an extensive set of simulated TROPOMI data in order to assess the uncertainty of single SIF retrievals and subsequent spatio-temporal composites. Our results illustrate the enormous improvement in SIF monitoring achievable with TROPOMI with respect to comparable spectrometers currently in-flight, such as the Global Ozone Monitoring Experiment-2 (GOME-2) instrument. We find that TROPOMI can reduce global uncertainties in SIF mapping by more than a factor of 2 with respect to GOME-2, which comes together with an approximately 5-fold improvement in spatial sampling. Finally, we discuss the potential of TROPOMI to map other important vegetation parameters at a global scale with moderate spatial resolution and short revisit time. Those include leaf photosynthetic pigments and proxies for canopy structure, which will complement SIF retrievals for a self-contained description of vegetation condition and functioning

Analysis of dependence among size, rate and duration in internet flows

In this paper we examine rigorously the evidence for dependence among data size, transfer rate and duration in Internet flows. We emphasize two statistical approaches for studying dependence, including Pearson's correlation coefficient and the extremal dependence analysis method. We apply these methods to large data sets of packet traces from three networks. Our major results show that Pearson's correlation coefficients between size and duration are much smaller than one might expect. We also find that correlation coefficients between size and rate are generally small and can be strongly affected by applying thresholds to size or duration. Based on Transmission Control Protocol connection startup mechanisms, we argue that thresholds on size should be more useful than thresholds on duration in the analysis of correlations. Using extremal dependence analysis, we draw a similar conclusion, finding remarkable independence for extremal values of size and rate.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS268 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

CP--odd Correlation in the Decay of Neutral Higgs Boson into ZZZZ, W+W−W^+W^-, or ttˉt{\bar t}

We investigate the possibility of detecting CP--odd angular correlations in the various decay modes of the neutral Higgs boson including the modes of a $ZZ$ pair, a $W^+W^-$ pair, or a heavy quark pair. It is a natural way to probe the CP character of the Higgs boson once it is identified. Final state interactions (i.e. the absorptive decay amplitude) is not required in such correlations. As an illustrative example we take the fundamental source of the CP nonconservation to be in the Yukawa couplings of the Higgs boson to the heavy fermions. A similar correlation in the process $e^+e^- \to l^+ l^- H$ is also proposed. Our analysis of these correlations will be useful for experiments in future colliders such as LEP II, SSC, LHC or NLC.Comment: 16 pages, plus 8 postscript graphs not posted befor

Split-beam echosounder observations of natural methane seep variability in the northern Gulf of Mexico

A method for positioning and characterizing plumes of bubbles from marine gas seeps using an 18 kHz scientific split-beam echo sounder (SBES) was developed and applied to acoustic observations of plumes of presumed methane gas bubbles originating at approximately 1400 m depth in the northern Gulf of Mexico. A total of 161 plume observations from 27 repeat surveys were grouped by proximity into 35 clusters of gas vent positions on the seafloor. Profiles of acoustic target strength per vertical meter of plume height were calculated with compensation for both the SBES beam pattern and the geometry of plume ensonification. These profiles were used as indicators of the relative fluxes and fates of gas bubbles acoustically observable at 18 kHz and showed significant variability between repeat observations at time intervals of 1 h–7.5 months. Active gas venting was observed during approximately one third of the survey passes at each cluster. While gas flux is not estimated directly in this study owing to lack of bubble size distribution data, repeat surveys at active seep sites showed variations in acoustic response that suggest relative changes in gas flux of up to 1 order of magnitude over time scales of hours. The minimum depths of acoustic plume observations at 18 kHz averaged 875 m and frequently coincided with increased amplitudes of acoustic returns in layers of biological scatterers, suggesting acoustic masking of the gas bubble plumes in these layers. Minimum plume depth estimates were limited by the SBES field of view in only five instances

A data-analysis strategy for detecting gravitational-wave signals from inspiraling compact binaries with a network of laser-interferometric detectors

A data-analysis strategy based on the maximum-likelihood method (MLM) is presented for the detection of gravitational waves from inspiraling compact binaries with a network of laser-interferometric detectors having arbitrary orientations and arbitrary locations around the globe. The MLM is based on the network likelihood ratio (LR), which is a function of eight signal-parameters that determine the Newtonian inspiral waveform. In the MLM-based strategy, the LR must be maximized over all of these parameters. Here, we show that it is possible to maximize it analytically over four of the eight parameters. Maximization over a fifth parameter, the time of arrival, is handled most efficiently by using the Fast-Fourier-Transform algorithm. This allows us to scan the parameter space continuously over these five parameters and also cuts down substantially on the computational costs. Maximization of the LR over the remaining three parameters is handled numerically. This includes the construction of a bank of templates on this reduced parameter space. After obtaining the network statistic, we first discuss `idealized' networks with all the detectors having a common noise curve for simplicity. Such an exercise nevertheless yields useful estimates about computational costs, and also tests the formalism developed here. We then consider realistic cases of networks comprising of the LIGO and VIRGO detectors: These include two-detector networks, which pair up the two LIGOs or VIRGO with one of the LIGOs, and the three-detector network that includes VIRGO and both the LIGOs. For these networks we present the computational speed requirements, network sensitivities, and source-direction resolutions.Comment: 40 pages, 2 figures, uses RevTex and psfig, submitted to Phys. Rev. D, A few minor changes adde

Analytical QCD and multiparticle production

We review the perturbative approach to multiparticle production in hard collision processes. It is investigated to what extent parton level analytical calculations at low momentum cut-off can reproduce experimental data on the hadronic final state. Systematic results are available for various observables with the next-to-leading logarithmic accuracy (the so-called modified leading logarithmic approximation - MLLA). We introduce the analytical formalism and then discuss recent applications concerning multiplicities, inclusive spectra, correlations and angular flows in multi-jet events. In various cases the perturbative picture is surprisingly successful, even for very soft particle production.Comment: 97 pages, LaTeX, 22 figures, uses sprocl.sty (included

La geometría de visualización afecta el dicromatismo sexual y la conspicuidad de la coloración del plumaje no iridiscente de Tersina viridis

Some types of plumage color are difficult to characterize spectrophotometrically because the properties of the reflected light change with viewing geometry (i.e. the relative positions of the light source and the observer, and the orientation of the feather). This is the case for the noniridescent plumage coloration of the Swallow Tanager (Tersina viridis), which seems to change from a human perspective as the angle between the light source and the observer varies. In this study, we measured plumage reflectance with different angles of illumination and/or observation, and used avian visual models to evaluate the change in sexual dichromatism and conspicuousness with viewing geometry from a bird’s perspective. We also calculated different color parameters to assess how these changed with viewing conditions. Sexual dichromatism showed large changes, with its maximum coinciding with the angle combination between illuminant and observer that produced both the highest conspicuousness for males and the highest crypsis for females. The conspicuousness of males also varied with viewing geometry, and was consistently less when viewed by the visual system of a potential avian predator (VS) than by that of a conspecific (UVS). The change in perceived coloration was mainly related to large variation in hue and chroma in the plumage of males as the relative angle between the illumination and observation probes changed. Our results show that viewing geometry can alter color perception, even for noniridescent plumage coloration. Therefore, the relative position of the light source and the observer should be considered in studies of avian visual communication, particularly for species with plumage coloration similar to that of Swallow Tanagers.Algunos tipos de colores del plumaje son difíciles de caracterizar espectrofotometricamente debido a que las propiedades de la luz que reflejada varían con la geometría de visualización (es decir, la posición relativa de la fuente lumínica, el observador y la pluma). Este es el caso de la coloración no-iridiscente de la Tersina viridis, que parece cambiar desde la perspectiva humana al modificarse el ángulo conformado entre el observador y la fuente de luz. En este trabajo medimos la reflectancia del plumaje con diferentes ángulos de iluminación y/o observación y empleamos modelos visuales avianos para evaluar el cambio en dicromatismo sexual y conspicuidad. Tambien calculamos parámetros descriptores de la coloración para determinar cómo cambian estos en función de la geometría de visualización. El dicromatismo sexual mostró una amplia variación, siendo máximo con la combinación de ángulos entre iluminante y observador que también produjo el máximo de conspicuidad en los machos y el máximo de cripsis en las hembras. La conspicuidad de los machos tambien varió con la geometría de visualización y además fue consistentemente menor para sistemas visuales avianos menos sensibles al UV (como los de los máximos potenciales predadores de esta especie) que para sus conspecíficos, que serían más sensibles a longitudes de onda del UV. El cambio percibido en la coloración estuvo principalmente relacionado a una gran variación en el tono y la saturación en el plumaje de los machos al cambiar el ángulo conformado entre la fuente lumínica y el observador. Nuestros resultados muestran que la geometría de visualización puede alterar la percepción del color, a un en plumajes no-iridiscentes. Por lo tanto, es importante considerar la posición relativa de la fuente de luz y el observador en estudios de comunicación visual en aves, particularmente en especies con coloración del plumaje como la de la Tersina viridis.Fil: Barreira, Ana Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: García, Natalia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lougheed, Stephen C.. Queens University, Department Of Biology; CanadáFil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin