55 research outputs found

    Determination of quantum numbers for several excited charmed mesons observed in B- -> D*(+)pi(-) pi(-) decays

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    A four-body amplitude analysis of the B − → D * + π − π − decay is performed, where fractions and relative phases of the various resonances contributing to the decay are measured. Several quasi-model-independent analyses are performed aimed at searching for the presence of new states and establishing the quantum numbers of previously observed charmed meson resonances. In particular the resonance parameters and quantum numbers are determined for the D 1 ( 2420 ) , D 1 ( 2430 ) , D 0 ( 2550 ) , D ∗ 1 ( 2600 ) , D 2 ( 2740 ) and D ∗ 3 ( 2750 ) states. The mixing between the D 1 ( 2420 ) and D 1 ( 2430 ) resonances is studied and the mixing parameters are measured. The dataset corresponds to an integrated luminosity of 4.7     fb − 1 , collected in proton-proton collisions at center-of-mass energies of 7, 8 and 13 TeV with the LHCb detector

    Updated measurement of decay-time-dependent CP asymmetries in D-0 -> K+ K- and D-0 -> pi(+)pi(-) decays

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    A search for decay-time-dependent charge-parity (CP) asymmetry in D0 \u2192 K+ K 12 and D0 \u2192 \u3c0+ \u3c0 12 decays is performed at the LHCb experiment using proton-proton collision data recorded at a center-of-mass energy of 13 TeV, and corresponding to an integrated luminosity of 5.4 fb^ 121. The D0 mesons are required to originate from semileptonic decays of b hadrons, such that the charge of the muon identifies the flavor of the neutral D meson at production. The asymmetries in the effective decay widths of D0 and anti-D0 mesons are determined to be A_\u393(K+ K 12) = ( 124.3 \ub1 3.6 \ub1 0.5) 7 10^ 124 and A_\u393(\u3c0+ \u3c0 12) = (2.2 \ub1 7.0 \ub1 0.8) 7 10^ 124 , where the uncertainties are statistical and systematic, respectively. The results are consistent with CP symmetry and, when combined with previous LHCb results, yield A_\u393(K+ K 12) = ( 124.4 \ub1 2.3 \ub1 0.6) 7 10^ 124 and A_\u393(\u3c0+ \u3c0 12) = (2.5 \ub1 4.3 \ub1 0.7) 7 10^ 124

    Updated measurement of decay-time-dependent CP asymmetries in D-0 -> K+ K- and D-0 -> pi(+)pi(-) decays

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    A search for decay-time-dependent charge-parity (CP) asymmetry in D-0 -> K+ K- and D-0 -> pi(+)pi(-) eff decays is performed at the LHCb experiment using proton-proton collision data recorded at a center-of-mass energy of 13 TeV, and corresponding to an integrated luminosity of 5.4 fb(-1). The D-0 mesons are required to originate from semileptonic decays of b hadrons, such that the charge of the muon identifies the flavor of the neutral D meson at production. The asymmetries in the effective decay widths of D-0 and (D) over bar (0) mesons are determined to be A(Gamma)(K+ K-) = (-4.3 +/- 3.6 +/- 0.5) x 10(-4) and A(Gamma) (K+ K- ) = (2.2 +/- 7.0 +/- 0.8) x 10(-4), where the uncertainties are statistical and systematic, respectively. The results are consistent with CP symmetry and, when combined with previous LHCb results, yield A(Gamma) (K+ K-) = (-4.4 +/- 2.3 +/- 0.6) x 10(-4) and A(Gamma) (pi(+)pi(-))= (2.5 +/- 4.3 +/- 0.7) x 10(-4)

    Síndrome de West: evolução clínica e eletrencefalográfica de 70 pacientes e resposta ao tratamento com hormônio adrenocorticotrófico, prednisona, vigabatrina, nitrazepam e ácido valpróico West syndrome: clinical and eletroencephalographic follow up of 70 patients and response to the adrenocorticotropic hormone, prednisone, vigabatrin, nitrazepam and valproate

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    Em estudo retrospectivo avaliamos a evolução clínica e eletrencefalográfica das formas criptogênica e sintomática da síndrome de West e analisamos a eficácia do hormônio adrenocorticotrófico, vigabatrina, prednisona, ácido valpróico e nitrazepam no controle dos espasmos. Participaram do estudo 70 pacientes, acompanhados por período maior que 2 anos. Doze (17%) eram criptogênicos e 58 (83%) sintomáticos. O grupo criptogênico apresentou percentagem significativamente maior de pacientes que frequentavam escola regular e desenvolvimento motor normal, melhor controle das crises epilépticas, tendência menor a evoluir para síndrome de Lennox Gastaut e 83,3% tiveram controle completo dos espasmos (72,4% dos pacientes do grupo sintomático obtiveram controle completo dos espasmos). O hormônio adrenocorticotrófico e a vigabatrina foram as drogas mais eficazes, controlando 68,75% e 60% dos espasmos, respectivamente, quando utilizados como droga de primeira escolha e 75% e 50%, respectivamente, como drogas de segunda escolha.<br>In a retrospective study we assessed the outcome of the criptogenic and symptomatic forms of West syndrome and evaluated the efficacy of adrenocorticotropic hormone, vigabatrin, prednisone, valproate and nitrazepam in the spasms control. Seventy patients were follwed up by 2 years. Twelve (17%) were criptogenics and 58 (83%) symptomatics. In criptogenic group significantly more patients were in regular school classes and with normal motor development, better control of seizure, less tendency to evoluate to Lennox Gastaut syndrome and 83.3% had control of spasms (72.4% of patients from symptomatic group had control of spasms). Adrenocorticotropic hormone and vigabatrin were the most efective drugs, with 68.75% and 60% of spasms control, respectivelly, when used as first line of therapy and 75% and 50%, respectivelly, as second line of therapy

    Highlights from the LHCb experiment

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    Highlights from the LHCb experiment

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    First measurement of the CPCP-violating phase ϕsdd\phi_s^{d\overline{d}} in Bs0(K+π)(Kπ+)B_s^0\to(K^+\pi^-)(K^-\pi^+) decays

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    First measurement of the CPCP-violating phase ϕsdd\phi_s^{d\overline{d}} in Bs0(K+π)(Kπ+)B_s^0\to(K^+\pi^-)(K^-\pi^+) decays

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    A search for Ξcc++D+pKπ+\it{\Xi}^{++}_{cc} \rightarrow D^{+} p K^{-} \pi^{+} decays

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    A search for Ξcc++D+pKπ+\it{\Xi}^{++}_{cc} \rightarrow D^{+} p K^{-} \pi^{+} decays

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