59 research outputs found

    Measurement of CP observables in B± → D(⁎)K± and B± → D(⁎)π± decays

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    Measurements of CP observables in B ± →D (⁎) K ± and B ± →D (⁎) π ± decays are presented, where D (⁎) indicates a neutral D or D ⁎ meson that is an admixture of D (⁎)0 and D¯ (⁎)0 states. Decays of the D ⁎ meson to the Dπ 0 and Dγ final states are partially reconstructed without inclusion of the neutral pion or photon, resulting in distinctive shapes in the B candidate invariant mass distribution. Decays of the D meson are fully reconstructed in the K ± π ∓ , K + K − and π + π − final states. The analysis uses a sample of charged B mesons produced in pp collisions collected by the LHCb experiment, corresponding to an integrated luminosity of 2.0, 1.0 and 2.0 fb −1 taken at centre-of-mass energies of s=7, 8 and 13 TeV, respectively. The study of B ± →D ⁎ K ± and B ± →D ⁎ π ± decays using a partial reconstruction method is the first of its kind, while the measurement of B ± →DK ± and B ± →Dπ ± decays is an update of previous LHCb measurements. The B ± →DK ± results are the most precise to date

    Measurement of CPCP asymmetries in D±ηπ±D^{\pm}\rightarrow \eta^{\prime} \pi^{\pm} and Ds±ηπ±D_s^{\pm}\rightarrow \eta^{\prime} \pi^{\pm} decays

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    See paper for full list of authors - All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-041.html - Submitted to Phys. Lett. BInternational audienceA search for CP violation in D±→η′π± and D±s→η′π± decays is performed using proton-proton collision data, corresponding to an integrated luminosity of 3 fb−1, recorded by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The measured CP-violating charge asymmetries are ACP(D±→η′π±)=(−0.61±0.72±0.55±0.12)% and ACP(D±s→η′π±)=(−0.82±0.36±0.24±0.27)%, where the first uncertainties are statistical, the second systematic, and the third are the uncertainties on the ACP(D±→K0Sπ±) and ACP(D±s→ϕπ±) measurements used for calibration. The results represent the most precise measurements of these asymmetries to date

    Measurement of B0B^0, Bs0B^0_s, B+B^+ and Λb0\Lambda^0_b production asymmetries in 7 and 8 TeV proton-proton collisions

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    See paper for full list of authors - All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-062.html - Submitted to Phys. Lett. B.International audienceThe B0, B0s, B+ and Λ0b hadron production asymmetries are measured using a data sample corresponding to an integrated luminosity of 3.0 fb−1, collected by the LHCb experiment in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. The measurements are performed as a function of transverse momentum and rapidity of the b hadrons within the LHCb detector acceptance. The overall production asymmetries, integrated over transverse momentum and rapidity, are also determined

    Search for CPCP violation in the phase space of D0π+ππ+πD^0\rightarrow\pi^+\pi^-\pi^+\pi^- decays

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    A search for time-integrated CPCP violation in the Cabibbo-suppressed decay \mbox{D^0\rightarrow\pi^+\pi^-\pi^+\pi^-} is performed using an unbinned, model-independent technique known as the energy test. This is the first application of the energy test in four-body decays. The search is performed for PP-even CPCP asymmetries and, for the first time, is extended to probe the PP-odd case. Using proton-proton collision data corresponding to an integrated luminosity of 3.0 fb1^{-1} collected by the LHCb detector at centre-of-mass energies of s=\sqrt{s}=7 TeV and 8 TeV, the world's best sensitivity to CPCP violation in this decay is obtained. The data are found to be consistent with the hypothesis of CPCP symmetry with a pp-value of (4.6±0.5)%(4.6\pm0.5)\% in the PP-even case, and marginally consistent with a pp-value of (0.6±0.2)%(0.6\pm0.2)\% in the PP-odd case, corresponding to a significance for CPCP non-conservation of 2.7 standard deviations.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-044.htm

    First observation of forward ZbbˉZ \rightarrow b \bar{b} production in pppp collisions at s=8\sqrt{s}=8 TeV

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    The decay Z→bb¯ is reconstructed in pp collision data, corresponding to 2 fb −1 of integrated luminosity, collected by the LHCb experiment at a centre-of-mass energy of s=8 TeV. The product of the Z production cross-section and the Z→bb¯ branching fraction is measured for candidates in the fiducial region defined by two particle-level b -quark jets with pseudorapidities in the range 2.220 GeV and dijet invariant mass in the range 4520GeVanddijetinvariantmassintherange GeV and dijet invariant mass in the range 45 < m_{jj} < 165GeV.Fromasignalyieldof GeV. From a signal yield of 5462 \pm 763 Z \rightarrow b \bar{b}events,wheretheuncertaintyisstatistical,aproductioncrosssectiontimesbranchingfractionof events, where the uncertainty is statistical, a production cross-section times branching fraction of 332 \pm 46 \pm 59pbisobtained,wherethefirstuncertaintyisstatisticalandthesecondsystematic.Themeasuredsignificanceofthesignalyieldis6.0standarddeviations.Thismeasurementrepresentsthefirstobservationofthe pb is obtained, where the first uncertainty is statistical and the second systematic. The measured significance of the signal yield is 6.0 standard deviations. This measurement represents the first observation of the Z \rightarrow b \bar{b}productionintheforwardregionof production in the forward region of pp$ collisions

    Biopsia hepática em cães: relação entre qualidade da amostra e grau de conclusão do diagnóstico

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    O presente estudo objetivou analisar a qualidade do diagnóstico de biopsias colhidas com agulhas tipo aspirativa e cortante, comparando-as ao exame histológico post-mortem do fígado de cães portadores de afecções hepáticas. Foram utilizados 60 cães, sem distinção de sexo, raça ou idade. As biopsias foram procedidas com agulhas tipo Menghini<FONT FACE=Symbol>Ò</FONT> (de natureza aspirativa) e agulhas tipo Tru-Cut<FONT FACE=Symbol>Ò</FONT> (de natureza cortante). As biopsias foram colhidas utilizando-se a técnica percutânea transabdominal. O diagnóstico referente à agulha tipo Tru-Cut<FONT FACE=Symbol>Ò</FONT> não diferiu do diagnóstico referente à agulha tipo Menghini<FONT FACE=Symbol>Ò</FONT>. O referente à agulha tipo Tru-Cut<FONT FACE=Symbol>Ò</FONT> foi o que apresentou maior índice de concordância, 88,3% de acertos. A agulha tipo Tru-Cut<FONT FACE=Symbol>Ò</FONT> apresentou excelentes resultados independente da natureza das lesões, enquanto que a agulha tipo Menghini<FONT FACE=Symbol>Ò</FONT> falhou nos casos de fibrose

    Biopsia hepática em cães: relação entre qualidade da amostra e grau de conclusão do diagnóstico

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    O presente estudo objetivou analisar a qualidade do diagnóstico de biopsias colhidas com agulhas tipo aspirativa e cortante, comparando-as ao exame histológico post-mortem do fígado de cães portadores de afecções hepáticas. Foram utilizados 60 cães, sem distinção de sexo, raça ou idade. As biopsias foram procedidas com agulhas tipo MenghiniÒ (de natureza aspirativa) e agulhas tipo Tru-CutÒ (de natureza cortante). As biopsias foram colhidas utilizando-se a técnica percutânea transabdominal. O diagnóstico referente à agulha tipo Tru-CutÒ não diferiu do diagnóstico referente à agulha tipo MenghiniÒ. O referente à agulha tipo Tru-CutÒ foi o que apresentou maior índice de concordância, 88,3% de acertos. A agulha tipo Tru-CutÒ apresentou excelentes resultados independente da natureza das lesões, enquanto que a agulha tipo MenghiniÒ falhou nos casos de fibrose.The aim of this study was to evaluate the diagnostic effectiveness of biopsies collected with aspiration or cutting needles, which were compared to the post-mortem histologic examination of the liver from dogs with hepatic diseases. Sixty mixed breed dogs of several ages and of both sexes were studied. Biopsies were collected with Menghini needles (aspiration) or Tru-Cut needles (cutting). The diagnoses obtained with the Tru-Cut needle did not differ statistically from diagnoses obtained with the Menghini needle. The diagnoses obtained with the Tru-Cut needle had a better agreement index, totaling 88.3% of correct diagnoses. The Tru-Cut needle provided excellent results, regardless of the nature of the lesions, whereas the Menghini needle failed when fibrosis was present
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