57,465 research outputs found
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
Branching fraction and CP asymmetry of the decays B+→K0Sπ+ and B+→K0SK+
No full textAn analysis of B+ → K0
Sπ+ and B+ → K0
S K+ decays is performed with the LHCb experiment. The pp
collision data used correspond to integrated luminosities of 1 fb−1 and 2 fb−1 collected at centre-ofmass
energies of
√
s = 7 TeV and
√
s = 8 TeV, respectively. The ratio of branching fractions and the
direct CP asymmetries are measured to be B(B+ → K0
S K+
)/B(B+ → K0
Sπ+
) = 0.064 ± 0.009 (stat.) ±
0.004 (syst.), ACP(B+ → K0
Sπ+
) = −0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ → K0
S K+
) =
−0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at
√
s = 7 TeV is used to search for
B+
c
→ K0
S K+ decays and results in the upper limit ( fc · B(B+
c
→ K0
S K+
))/( fu · B(B+ → K0
Sπ+
)) <
5.8 × 10−2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ¯b
quark
into a B+
c or a B+ meson, respectively
First observation of the decay Bs0→K*0K*0
No full textThe first observation of the decay B0s→K∗0K∗0 is reported using 35 pb−1 of data collected by LHCb in proton–proton collisions at a centre-of-mass energy of 7 TeV. A total of 49.8±7.5 B0s→(K+π−)(K−π+) events are observed within ±50 MeV/c2 of the B0s mass and 746 MeV/c2 < mKπ < 1046 MeV/c2, mostly coming from a resonant B0s→K∗0K∗0 signal. The branching fraction and the CP-averaged K∗0 longitudinal polarization fraction are measured to be B(B0s→K∗0K∗0)=(2.81±0.46(stat.)±0.45(syst.)±0.34(fs/ fd))×10−5 and fL =0.31±0.12(stat.)±0.04(syst.)
Measurement of the CKM angle gamma from a combination of B->Dh analyses
No full textA combination of three LHCb measurements of the CKM angle gamma is presented. The decays B->DK and B->Dpi are used, where D denotes an admixture of D0 and D0-bar mesons, decaying into K+K-, pi+pi-, K+-pi-+, K+-pi-+pi+-pi-+, KSpi+pi-, or KSK+K- final states. All measurements use a dataset corresponding to 1.0 fb-1 of integrated luminosity. Combining results from B->DK decays alone a best-fit value of gamma = 72.0 deg is found, and confidence intervals are set gamma in [56.4,86.7] deg at 68% CL, gamma in [42.6,99.6] deg at 95% CL. The best-fit value of gamma found from a combination of results from B->Dpi decays alone, is gamma = 18.9 deg, and the confidence intervals gamma in [7.4,99.2] deg or [167.9,176.4] deg at 68% CL, are set, without constraint at 95% CL. The combination of results from B->DK and B->Dpi decays gives a best-fit value of gamma = 72.6 deg and the confidence intervals gamma in [55.4,82.3] deg at 68% CL, gamma in [40.2,92.7] deg at 95% CL are set. All values are expressed modulo 180 deg, and are obtained taking into account the effect of D0-D0bar mixing
A sociologia antropocêntrica de Alberto Guerreiro Ramos
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas. Programa de Pós-Graduação em Sociologia Política.No elenco das diferentes modalidades de estudos que sobre o pensamento sociológico de Alberto Guerreiro Ramos já foram realizadas, esta tese se coloca como uma possibilidade de interpretação que propicie aclarar, não as pontualidades temáticas ou as respostas aos problemas contingentes a que este sociólogo se propôs pensar, mas a coerência de suas crenças no tempo. Segundo pensamos, esta interpretação pautada na coerência das crenças guerreirianas pode trazer elucidações fundamentais acerca do alcance, do sentido e da finalidade da construção teórica à qual ele se dedicou, dos principais conceitos, modelos e proposituras por ele construídas, bem como permite justificar a mobilização e apropriação de conceitos e correntes teóricas por ele procedidas. Neste sentido, a tese que aqui se apresenta defende que há, no conjunto da obra de Guerreiro Ramos, uma forte crença da premência de um novo humanismo e, em termos correlatos, de um novo tipo humano, a partir dos quais seria possível teorizar sobre a vida humana individual e associada. Uma expressão marcante dessa crença do autor está na preocupação e no pressuposto por ele assumidos de que a sociedade deveria ser vertida ao homem, e não o inverso. Esta crença tem seu correspondente na afirmativa de Protágoras, e com a qual Aristóteles estava de pleno acordo: anthrôpos metro panthô chrématon (o homem é a medida de todas as coisas humanas). Munido deste humanismo radical, nosso sociólogo passou em revista os pressupostos sobre o homem que legitimavam a ciência social de sua época, denunciou os principais obstáculos sociais impeditivos de um processo de humanização e articulou a sua proposta de uma nova ciência do social. É neste sentido que afirmamos ser antropocêntrica a sociologia de Guerreiro Ramos. Esta pesquisa, assim, atenta para uma questão que até agora é inédita, tendo-se em conta todos os trabalhos que trataram da obra ou dos estudos de Guerreiro Ramos. Several studies about Ramos#s sociological thought have been written in Brazil. The purpose of this dissertation is to be an interpretation to clarify some elements that support the Ramos#s coherence of beliefs in time. This coherence exists in all Ramos#s work, since his juvenile papers until his last book. We believe that our interpretation can be help in the understanding of the reach, of the meaning, and of the final aim of his theoretical work or of his concepts, models, and sociological proposals. Also we believe that our interpretation can help in the understanding of his displacement of concepts and filiations with currents of thought. In this dissertation we demonstrated that there is in the Ramos#s works a strong belief in the urgency of a new humanism, and a new human type, starting from which would be possible to theorize about the individual and associated human life, in others words, a humanism which the man was the measure of everything. An example of this is his concern and presupposition that the society should be structured for the man and not the opposite. With this radical humanist point of view, Ramos revised the man presupposition of the social science of his time, denounced the main social obstacles to the humanization process, and proposed a new science of social. In this way, we affirm that the Ramos#s sociological thought is anthrophocentric
Measurement of CP observables in B-+/- -> D(*)K-+/- and B-+/- -> D(*)pi(+/-) decays
No full textMeasurements of CP observables in B-+/- -> D(*)K-+/- and B-+/- -> D(*)pi(+/-) decays are presented, where D(*) indicates a neutral Dor D* meson that is an admixture of D(*)(0) and (D) over bar(*)(0) states. Decays of the D* meson to the D pi(0)and D gamma final states are partially reconstructed without inclusion of the neutral pion or photon, resulting in distinctive shapes in the Bcandidate invariant mass distribution. Decays of the D meson are fully reconstructed in the K-+/-pi(-/+), K+K- and pi(+)pi(-) final states. The analysis uses a sample of charged Bmesons produced in ppcollisions collected by the LHCb experiment, corresponding to an integrated luminosity of 2.0, 1.0 and 2.0fb- 1taken at centre- of- mass energies of root s = 7, 8 and 13 TeV, respectively. The study of B-perpendicular to -> D*K-perpendicular to and B-perpendicular to -> D*pi(perpendicular to) decays using a partial reconstruction method is the first of its kind, while the measurement of B-+/- -> DK +/- and B-+/- -> D pi(+/-) decays is an update of previous LHCb measurements. The B-+/- -> DK +/- results are the most precise to date. (c) 2017 The Author. Published by Elsevier B. V
Search for the suppressed decays and
No full textSee paper for full list of authors - 18 pages, 12 figures - Submitted to Phys. Lett. BInternational audienceA search is made for the highly-suppressed B meson decays and using a data sample corresponding to an integrated luminosity of 3.0 collected by the LHCb experiment in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. No evidence is found for the decays, and upper limits at 90\% confidence level are determined to be and
Observation of the Λ b 0 → J / ψ Ξ - K + decay
No full textAbstract Using proton–proton collision data corresponding to an integrated luminosity of 140 fb - 1 collected by the CMS experiment at s = 13 Te V , the Λ b 0 → J / ψ Ξ - K + decay is observed for the first time, with a statistical significance exceeding 5 standard deviations. The relative branching fraction, with respect to the Λ b 0 → ψ ( 2 S ) Λ decay, is measured to be B ( Λ b 0 → J / ψ Ξ - K + ) / B ( Λ b 0 → ψ ( 2 S ) Λ ) = [ 3.38 ± 1.02 ± 0.61 ± 0.03 ] % , where the first uncertainty is statistical, the second is systematic, and the third is related to the uncertainties in B ( ψ ( 2 S ) → J / ψ π + π - ) and B ( Ξ - → Λ π - )
Measurement of branching fractions for B → χc1(2)K (K*) at Belle
No full textWe have measured the branching fractions for the exclusive decay modes B→χc1(2)K(K*) using a 140 fb-1 data sample collected by the Belle detector at the KEKB asymmetric-energy e +e- collider. The measured branching fractions for B +→χc1K+, B0→χ c1K0, B0→χc1K* 0 and B+→χc1K*+ decay modes are (4.5±0.2±0.5)×10-4, (3.5±0.3±0.5)×10-4, (3.1±0.3±0.7) ×10-4 and (4.1±0.6±0.9)×10-4, respectively, where the first error is statistical and the second error is systematic. We do not observe statistically significant signals for the B→χc2K(K*) decay modes and set upper limits at the 90% confidence level. We also study the helicity distribution for B→χc1K* decay mode and show that the longitudinal polarization component is dominant. © 2006 Elsevier B.V. All rights reserved.LPH
Inquiry into the interlocution of students engaged with mathematics: appreciating links between research and practice
No full textFor either to be useful, links between research and practice are critical. Just as important are connections between the practice of students engaged in mathematical activity and research that seeks to understand that practice. This research report explores lessons that researchers and practitioners can learn from an inquiry into the interlocution of students working collaboratively in small groups when engaged in talking and listening to each other. We use the term interlocution to denote discursive practices of learners in conversational exchanges. Questions that motivate this research included the following. What discursive practices do interlocutors employ as they work collaboratively to understand and resolve mathematical tasks? How do these practices influence the growth of their mathematical ideas? In what ways do their discursive practices help them move from a contextualized, situated task to generalize the task or their solution? Do students' discursive practices assist them to connect and generalize ideas from a new problem to others on which they have worked?Powell, A. B., & Maher, C. A. (2002). Inquiry into the interlocution of students engaged with mathematics: Appreciating links between research and practice. In D.S. Mewborn, P. Sztajn, D.Y. White, H.G. Wiegel, R.L. Bryant & K. Nooney (Eds.), Proceedings of the twenty-fourth annual meeting of the North American Chapter of the International Group for the Psychology of Mathematics Education (Athens, Georgia) (Vol. 1, pp. 317-329). Columbus, OH: ERIC Clearinghouse for Science, Mathematics, and Environmental Education
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