57 research outputs found

    A lattice study of the exclusive BKγB \to K^* \gamma decay amplitude, using the Clover action at β=6.0\beta=6.0

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    We present the results of a numerical calculation of the BKγB\to K^* \gamma form factors. The results have been obtained by studying the relevant correlation functions at β=6.0\beta=6.0, on an 183×6418^3 \times 64 lattice, using the O(a){\rm O(a)}-improved fermion action, in the quenched approximation. From the study of the matrix element we have obtained the form factor T1(0)T_1(0) which controls the exclusive decay rate. The results are compared with the recent results from CLEO. We also discuss the compatibility between the scaling laws predicted by the Heavy Quark Effective Theory (HQET) and pole dominance, by studying the mass- and q2q^2-dependence of the form factors. From our analysis, it appears that the form factors follow a mass behaviour compatible with the predictions of the HQET and that the q2q^2-dependence of T2T_2 is weaker than would be predicted by pole dominance.Comment: 17 pages, LaTeX + epsf.sty. Uuencoded, compressed, tar archive including the text and one postscript figur

    Impact of dried brewers’ grains supplementation on performance, metabolism and meat quality of broiler chickens

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    The objective was to evaluate increasing levels of dried brewers’ grains (DBG) in feed for broiler chickens from 1 to 21 days old and their effect on performance, blood parameters, intestinal morphometry, carcass characteristics and meat quality. The design was completely randomized with six treatments, which consisted of various levels of DBG inclusion, namely 0 (no inclusion), 20, 40, 60, 80, and 100 g/kg with seven replications and 17 animals per experimental unit, totalling 714 male broilers. Performance parameters, blood biochemical profile, morphology of the intestinal epithelium (duodenum), and carcass yield and composition were evaluated. Feed intake was not changed by DBG inclusion levels. Nor were weight gain and feed conversion ratio. Serum cholesterol levels were not influenced, and there were no effects on triglyceride, uric acid and creatinine levels. Enzyme aspartate aminotransferase showed a quadratic effect, as did alanine aminotransferase, with higher values at 79.5 and 63.9 g/kg DBG inclusion, respectively. No changes in carcass yield and relative organ weight were observed. The composition of the carcass in ether extract showed a quadratic effect, as fat deposition rate, with lowest values at 62.8 and 62.4 g/kg of DBG inclusion levels, respectively. Crude protein levels in carcass reduced linearly, as did fat deposition rate. The parameters of intestinal morphology and meat quality were not changed. Dried brewers’ grains can be included in broiler diet from 1 to 21 days at levels up to 100 g/kg without influencing the metabolic parameters and broiler performance. Keywords: alternative feed, blood, by-product, intestinal villi, performanc

    GW241011 and GW241110: exploring binary formation and fundamental physics with asymmetric, high-spin black hole coalescences

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    We report the observation of gravitational waves from two binary black hole coalescences during the fourth observing run of the LIGO–Virgo–KAGRA detector network, GW241011 and GW241110. The sources of these two signals are characterized by rapid and precisely measured primary spins, nonnegligible spin–orbit misalignment, and unequal mass ratios between their constituent black holes. These properties are characteristic of binaries in which the more massive object was itself formed from a previous binary black hole merger and suggest that the sources of GW241011 and GW241110 may have formed in dense stellar environments in which repeated mergers can take place. As the third-loudest gravitational-wave event published to date, with a median network signal-to-noise ratio of 36.0, GW241011 furthermore yields stringent constraints on the Kerr nature of black holes, the multipolar structure of gravitational-wave generation, and the existence of ultralight bosons within the mass range 10−13–10−12 eV

    Search for supersymmetry in final states with missing transverse momentum and charm-tagged jets using 139 fb−1 of proton-proton collisions at √s = 13 TeV with the ATLAS detector

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    Search for supersymmetry using vector boson fusion signatures and missing transverse momentum in pp collisions at √s = 13 TeV with the ATLAS detector

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    This paper presents a search for supersymmetric particles in models with highly compressed mass spectra, in events consistent with being produced through vector boson fusion. The search uses 140 fb−1 of proton-proton collision data at √s = 13 TeV collected by the ATLAS experiment at the Large Hadron Collider. Events containing at least two jets with a large gap in pseudorapidity, large missing transverse momentum, and no reconstructed leptons are selected. A boosted decision tree is used to separate events consistent with the production of supersymmetric particles from those due to Standard Model backgrounds. The data are found to be consistent with Standard Model predictions. The results are interpreted using simplified models of R-parity-conserving supersymmetry in which the lightest supersymmetric partner is a bino-like neutralino with a mass similar to that of the lightest chargino and second-to-lightest neutralino, both of which are wino-like. Lower limits at 95% confidence level on the masses of next-to-lightest supersymmetric partners in this simplified model are established between 117 and 120 GeV when the lightest supersymmetric partners are within 1 GeV in mass

    Test of lepton flavour universality in W-boson decays into electrons and τ-leptons using pp collisions at √s = 13 TeV with the ATLAS detector

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    Search for charged Higgs bosons produced in top-quark decays or in association with top quarks and decaying via H±→τ±ντ in 13 TeV pp collisions with the ATLAS detector

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    Charged Higgs bosons produced either in top-quark decays or in association with a top quark, subsequently decaying via H±→τ±ντ, are searched for in 140  fb−1 of proton-proton collision data at s=13  TeV recorded with the ATLAS detector. Depending on whether the top quark is produced together with the H± decays hadronically or semileptonically, the search targets τ+jets or τ+lepton final states, in both cases with a τ-lepton decaying into a neutrino and hadrons. No significant excess over the Standard Model background expectation is observed. For the mass range of 80≤mH±≤3000  GeV, upper limits at 95% confidence level are set on the production cross section of the charged Higgs boson times the branching fraction B(H±→τ±ντ) in the range 4.5 pb–0.4 fb. In the mass range 80–160 GeV, assuming the Standard Model cross section for tt¯ production, this corresponds to upper limits between 0.27% and 0.02% on B(t→bH±)×B(H±→τ±ντ).</jats:p
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