312 research outputs found

    BHLS2_2 and π+π−\pi^+ \pi^- Final State Interaction~: The η/ηâ€Č→π+Ï€âˆ’Îł\eta/\eta' \rightarrow \pi^+ \pi^- \gamma Decays and the Muon HVP

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    The departure of the latest FNAL experimental average for the muon anomalous magnetic moment aÎŒ=(gΌ−2)/2a_\mu=(g_\mu-2)/2 measurements having increased from 4.2σ4.2 \sigma to 5.0σ5.0 \sigma , with respect to the White Paper (WP) consensus, it may indicate a hint for new physics. As the most delicate piece of aÎŒa_\mu is its leading order HVP part aÎŒHVP−LOa_\mu^{HVP-LO}, methods to ascertain its theoretical value are crucial to interpret appropriately this departure with the measurement. We therefore propose to examine closely the dipion spectra from the η/ηâ€Č→π+Ï€âˆ’Îł\eta/\eta' \rightarrow \pi^+ \pi^- \gamma decays in the Hidden Local Symmetry (HLS) context using its BHLS2_2 broken variant. We thus have at disposal a framework where the close relationship of the dipion spectra from the η/ηâ€Č\eta/\eta' and τ\tau decays and of the e+e−→π+π−e^+e^- \to \pi^+\pi^- annihilation can be simultaneously considered. A special focus is put to the high statistic dipion spectra from the η\eta decay collected by the KLOE/KLOE2 Collaboration and ηâ€Č\eta' decay collected by the BESIII Collaboration. It is shown that, once the Final State Interaction (FSI) effects are accounted for, the BHLS2_2 framework provides a fair account of their dipion spectra. More precisely, it is first proven that a single FSI polynomial is requested, common to both the η\eta and ηâ€Č\eta' dipion spectra. Moreover, it is shown that fits involving the η/ηâ€Č/τ\eta/\eta'/\tau dipion spectra, and excluding the e+e−→π+π−e^+e^- \to \pi^+\pi^- annihilation data, allow for a prediction of the pion form factor data Fπ(s)F_\pi(s) which fairly agree with the usual dipion spectra collected in the e+e−→π+π−e^+e^- \to \pi^+\pi^- annihilation channel. Even if more precise η/ηâ€Č/τ\eta/\eta'/\tau dipion spectra would help to be fully conclusive, this may already be considered as supporting the Dispersive Approach results for aÎŒHVP−LOa_\mu^{HVP-LO}

    The Pion Form Factor Within the Hidden Local Symmetry Model

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    We analyze a pion form factor formulation which fulfills the Analyticity requirement within the Hidden Local Symmetry (HLS) Model. We show that it implies an ss--dependent dressing of the Ïâˆ’Îł\rho-\gamma VMD coupling and an account of several coupled channels. The corresponding function Fπ(s)F_\pi(s) provides nice fits of the pion form factor data from s=−0.25s=-0.25 to s=1s=1 GeV2^2. It is shown that the coupling to KKˉK \bar{K} has little effects, while \omg \pi^0 improves significantly the fit quality below the ϕ\phi mass. All parameters, except for the subtraction polynomial coefficients are fixed from the rest of the HLS phenomenology. The fits show consistency with the expected behaviour of Fπ(s)F_\pi(s) at s=0s=0 up to O(s2){\cal O} (s^2) and with the phase shift data on ÎŽ11(s)\delta_1^1(s) from threshold to somewhat above the ϕ\phi mass. The \omg sector is also examined in relation with recent data from CMD--2.We analyze a pion form factor formulation which fulfills the Analyticity requirement within the Hidden Local Symmetry (HLS) Model. We show that it implies an ss--dependent dressing of the Ïâˆ’Îł\rho-\gamma VMD coupling and an account of several coupled channels. The corresponding function Fπ(s)F_\pi(s) provides nice fits of the pion form factor data from s=−0.25s=-0.25 to s=1s=1 GeV2^2. It is shown that the coupling to KKˉK \bar{K} has little effects, while \omg \pi^0 improves significantly the fit quality below the ϕ\phi mass. All parameters, except for the subtraction polynomial coefficients are fixed from the rest of the HLS phenomenology. The fits show consistency with the expected behaviour of Fπ(s)F_\pi(s) at s=0s=0 up to O(s2){\cal O} (s^2) and with the phase shift data on ÎŽ11(s)\delta_1^1(s) from threshold to somewhat above the ϕ\phi mass. The \omg sector is also examined in relation with recent data from CMD-2.We analyze a pion form factor formulation which fulfills the Analyticity requirement within the Hidden Local Symmetry (HLS) Model. We show that it implies an ss--dependent dressing of the Ïâˆ’Îł\rho-\gamma VMD coupling and an account of several coupled channels. The corresponding function Fπ(s)F_\pi(s) provides nice fits of the pion form factor data from s=−0.25s=-0.25 to s=1s=1 GeV2^2. It is shown that the coupling to KKˉK \bar{K} has little effects, while \omg \pi^0 improves significantly the fit quality below the ϕ\phi mass. All parameters, except for the subtraction polynomial coefficients are fixed from the rest of the HLS phenomenology. The fits show consistency with the expected behaviour of Fπ(s)F_\pi(s) at s=0s=0 up to O(s2){\cal O} (s^2) and with the phase shift data on ÎŽ11(s)\delta_1^1(s) from threshold to somewhat above the ϕ\phi mass. The \omg sector is also examined in relation with recent data from CMD-2.We analyze a pion form factor formulation which fulfills the Analyticity requirement within the Hidden Local Symmetry (HLS) Model. We show that it implies an ss--dependent dressing of the Ïâˆ’Îł\rho-\gamma VMD coupling and an account of several coupled channels. The corresponding function Fπ(s)F_\pi(s) provides nice fits of the pion form factor data from s=−0.25s=-0.25 to s=1s=1 GeV2^2. It is shown that the coupling to KKˉK \bar{K} has little effects, while ωπ0\omega \pi^0 improves significantly the fit quality below the ϕ\phi mass. All parameters, except for the subtraction polynomial coefficients are fixed from the rest of the HLS phenomenology. The fits show consistency with the expected behaviour of Fπ(s)F_\pi(s) at s=0s=0 up to O(s2){\cal O} (s^2) and with the phase shift data on ÎŽ11(s)\delta_1^1(s) from threshold to somewhat above the ϕ\phi mass. The ω\omega sector is also examined in relation with recent data from CMD-2

    An emotionally responsive AR art installation

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    In this paper, we describe a novel method of combining emotional input and an Augmented Reality (AR) tracking/display system to produce dynamic interactive art that responds to the perceived emotional content of viewer reactions and interactions. As part of the CALLAS project, our aim is to explore multimodal interaction in an Arts and Entertainment context. The approach we describe has been implemented as part of a prototype “showcase ” in collaboration with a digital artist designed to demonstrate how affective input from the audience of an interactive art installation can be used to enhance and enrich the aesthetic experience of the artistic work. We propose an affective model for combining emotionally-loaded participant input with aesthetic interpretations of interaction, together with a mapping which controls properties of dynamically generated digital art. 1

    MindSpaces:Art-driven Adaptive Outdoors and Indoors Design

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    MindSpaces provides solutions for creating functionally and emotionally appealing architectural designs in urban spaces. Social media services, physiological sensing devices and video cameras provide data from sensing environments. State-of-the-Art technology including VR, 3D design tools, emotion extraction, visual behaviour analysis, and textual analysis will be incorporated in MindSpaces platform for analysing data and adapting the design of spaces.</p

    Opposite-side flavour tagging of B mesons at the LHCb experiment

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    The calibration and performance of the oppositeside flavour tagging algorithms used for the measurements of time-dependent asymmetries at the LHCb experiment are described. The algorithms have been developed using simulated events and optimized and calibrated with B + →J/ψK +, B0 →J/ψK ∗0 and B0 →D ∗− ÎŒ + ΜΌ decay modes with 0.37 fb−1 of data collected in pp collisions at √ s = 7 TeV during the 2011 physics run. The oppositeside tagging power is determined in the B + → J/ψK + channel to be (2.10 ± 0.08 ± 0.24) %, where the first uncertainty is statistical and the second is systematic

    Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

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    The B0B^0-Bˉ0\bar B^0 oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives Δmd=0.493±0.012(stat)±0.009(syst)\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)} ps−1^{-1}.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

    Measurement of the Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction

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    The Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction is measured in a data sample corresponding to 0.41fb−1fb^{-1} of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2ÎČ\beta measurement from B0→J/ψKS0B^0\to J/\psi K_S^0 The time-integrated branching fraction is measured to be BF(Bs0→J/ψKS0)=(1.83±0.28)×10−5BF(B_s^0\to J/\psi K_S^0)=(1.83\pm0.28)\times10^{-5}. This is the most precise measurement to date
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