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Implementação do método k0-INAA no laboratório de análise por ativação com nêutrons do IPEN utilizando o programa k0-IAEA. Aplicação à análise de amostras geológicas; k0-NAA implementation and application at IPEN neutron activation laboratory by using the k0-IAEA software. Application to geological sample analysis

Mariano, Davi Brigatto
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/02/2012 Português
Relevância na Pesquisa
37.54%
O Laboratório de Análise por Ativação com Nêutrons (LAN-IPEN) vem analisando amostras geológicas, tais como rochas, solos e sedimentos, há vários anos, empregando o método de análise por ativação com nêutrons comparativa, visando estudos geoquímicos e ambientais. Este trabalho apresenta os resultados obtidos na implementação do método de padronização k0-INAA no LANIPEN, para a análise de amostras geológicas, utilizando o programa k0-IAEA, fornecido pela Agência Internacional de Energia Atômica (IAEA). A razão do fluxo de nêutrons térmico-epitérmico f e o fator α da distribuição de fluxo de nêutrons epitérmicos do reator IEA-R1 do IPEN foram determinados na estação pneumática de irradiação, e em uma posição de irradiação selecionada, para irradiações curtas e longas, respectivamente. Para obter esses fatores, foi utilizado o chamado método bare triple-monitor com 197Au-96Zr-94Zr. Para avaliar a exatidão e precisão do método, foram analisados os materiais geológicos de referência basalto JB-1 (GSJ) e BE-N (IWG-GIT), andesito AGV-1 (USGS), granito GS-N (ANRT), SOIL-7 (IAEA) e sedimento Buffalo River Sediment (NIST BRS-8704), que representam diferentes matrizes geológicas. Os resultados obtidos para até 30 elementos concordaram com os valores recomendados...

Estudo das covariâncias envolvidas no método k0 de análise por ativação neutrônica; Study of covariances involved in the k0 method of neutron activation analysis

Cardoso, Vanderlei
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 19/12/2011 Português
Relevância na Pesquisa
37.43%
O presente trabalho se propôs ao desenvolvimento de uma metodologia para o tratamento das incertezas do método k0 de Análise por Ativação Neutrônica (AAN), de forma abrangente e acurada, aplicando a metodologia de Análise por Covariâncias. Todos os parâmetros envolvidos na determinação da concentração de um elemento estudado foram analisados de forma criteriosa, estabelecendo as correlações entre eles. Também foram estabelecidas as possíveis correlações entre as concentrações de elementos diferentes, para a mesma amostra e em amostras diferentes. Este procedimento gerou um número grande de correlações que foram tratadas rigorosamente. Os dados para análise foram obtidos experimentalmente, por meio de irradiações efetuadas na posição de irradiação 24A próxima ao núcleo do reator de pesquisas IEA-R1 do IPEN-CNEN/SP. Os parâmetros α e ƒ, de caracterização do campo neutrônico, foram determinados, aplicando-se vários métodos apresentados na literatura. Um tratamento estatístico detalhado foi aplicado a cada uma das medidas, verificando-se as diversas incertezas parciais e suas correlações. Com o objetivo de aprofundar o estudo, foram escolhidos os alvos de 64Zn e 68Zn, para os quais foram determinados experimentalmente os parâmetros nucleares k0 e Q0...

Aplicação do método k0-INAA no Laboratório de Análise por Ativação com Nêutrons do IPEN utilizando o programa k0-IAEA. Análise de amostras biológicas.; k0-INAA application at IPEN Neutron Activation Laboratory by using the k0-IAEA program. Biological sample analysis

Puerta, Daniel Correa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/06/2013 Português
Relevância na Pesquisa
37.58%
Este estudo apresenta os resultados obtidos na aplicação do método de padronização k0-INAA no LANIPEN, para a análise de amostras biológicas, utilizando o programa k0-IAEA, fornecido pela Agência Internacional de Energia Atômica (IAEA). Os parâmetros de fluxo f e α do reator IEA-R1 do IPEN foram determinados na estação pneumática de irradiação e na posição de irradiação 24B/prateleira2, para irradiações curtas e longas, respectivamente. Para obter esses fatores, foi utilizado o chamado método bare triple-monitor com 197Au-96Zr- 94Zr. Para a verificação da precisão e exatidão do método, foram analisados os materiais biológicos de referência Peach Leaves (NIST SRM 1547), Mixed Polish Herbs (INCT-MPH-2) e Tomato Leaves (NIST SRM 1573a). Os critérios estatísticos Erro Relativo (bias, %), Coeficiente de Variação (CV) e U-score foram aplicados para avaliação dos resultados obtidos (média de seis replicatas). Os erros relativos (bias, %) ficaram, para maioria dos elementos, entre 0 e 30%, em relação aos valores certificados. Os Coeficientes de Variação foram inferiores a 20%, mostrando boa reprodutibilidade nos resultados obtidos experimentalmente. Os valores de U-score mostraram que todos os resultados...

Electromechanical properties of textured K0.5Na0.5NbO3 ceramics; Propriedades electromecânicas de cerâmicos de K0.5Na0.5NbO3 texturizado

Pinho, Rui Manuel de Oliveira
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
Português
Relevância na Pesquisa
37.15%
This work is about lead-free ceramic materials intended for electromechanical applications and candidates to replace lead-based electroceramics. One of the most widely used piezoelectric ceramics is lead zirconate titanate (PZT). However, it contains more than 60% of lead and it is toxic for humans and environment. In 2003, a directive from European Union has prohibited the use of potentially hazardous elements as lead. Due to the lack of competitive materials for PZT replacement an exception was created until a competitive alternative be found. Potassium and sodium niobate due to its high Curie temperature and moderate piezoelectric properties is currently one of the most promising lead-free materials for PZT substitution. However, its effective industrial adoption requires, among others, optimization of its properties. In this context, in this work we initially studied the effect of dopants, texturing and sintering temperature of KNN ceramics. For this purpose KNN ceramics doped with i) 1.5 mol% CuO + 2.0 mol% Li2O, ii) 1.5 mol% CuO + 4.0 mol% Li2O and iii) 1.5 mol% CuO + 0.5 mol% MnO using different sintering temperatures (1050, 1065 and 1080 °C) were prepared. In addition in order to maximize the preferential crystallographic orientation of the ceramic KNN (texturing)...

Effects of Processing Parameters on the Synthesis of (K0.5Na0.5)NbO3 Nanopowders by Reactive High-Energy Ball Milling Method

Duc Van, Nguyen
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
Publicado em 27/01/2014 Português
Relevância na Pesquisa
27.26%
The effects of ball milling parameters, namely, the ball-to-powder mass ratio and milling speed, on the synthesis of (K0.5Na0.5)NbO3 nanopowders by high-energy ball milling method from a stoichiometric mixture containing Na2CO3, K2CO3, and Nb2O5 were investigated in this paper. The results indicated that the single crystalline phase of (K0.5Na0.5)NbO3 was received in as-milled samples synthesized using optimized ball-to-powder mass ratio of 35 : 1 and at a milling speed of 600 rpm for 5 h. In the optimized as-milled samples, no remaining alkali carbonates that can provide the volatilizable potassium-containing species were found and (K0.5Na0.5)NbO3 nanopowders were readily obtained via the formation of an intermediate carbonato complex. This complex was mostly transformed into (K0.5Na0.5)NbO3 at temperature as low as 350°C and its existence was no longer detected at spectroscopic level when calcination temperature crossed over 700°C.

Solution structure of lysine-free (K0) ubiquitin

Huang, Tao; Li, Jess; Byrd, R Andrew
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.26%
Lysine-free ubiquitin (K0-Ub) is commonly used to study the ubiquitin-signaling pathway, where it is assumed to have the same structure and function as wild-type ubiquitin (wt-Ub). However, the K0-Ub 15N heteronuclear single quantum correlation NMR spectrum differs significantly from wt-Ub and the melting temperature is depressed by 19°C, raising the question of the structural integrity and equivalence to wt-Ub. The three-dimensional structure of K0-Ub was determined by solution NMR, using chemical shift and residual dipolar coupling data. K0-Ub adopts the same backbone structure as wt-Ub, and all significant chemical shifts can be related to interactions impacted by the K to R mutations.

Space-dependent probabilities for K0???K0?? oscillations

Ancochea, B.; Bramon, A.; Mu??oz-Tapia, R.; Nowakowski, M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.33%
We analyze K0???K0?? oscillations in space in terms of propagating wave packets with coherent KS and KL components. The oscillation probabilities PK0???K0(x) and PK0???K0??(x) depending only on the distance x, are defined through the time integration of a current density j(x,t) . The definition is such that it coincides with the experimental setting, thus avoiding some ambiguities and clarifying some controversies that have been discussed recently.

Electromechanical properties of engineered lead free potassium sodium niobate based materials; Propriedades electromecânicas de materiais à base de niobato de potássio e sódio

Rafiq, Muhammad Asif
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
27.43%
K0.5Na0.5NbO3 (KNN), is the most promising lead free material for substituting lead zirconate titanate (PZT) which is still the market leader used for sensors and actuators. To make KNN a real competitor, it is necessary to understand and to improve its properties. This goal is pursued in the present work via different approaches aiming to study KNN intrinsic properties and then to identify appropriate strategies like doping and texturing for designing better KNN materials for an intended application. Hence, polycrystalline KNN ceramics (undoped, non-stoichiometric; NST and doped), high-quality KNN single crystals and textured KNN based ceramics were successfully synthesized and characterized in this work. Polycrystalline undoped, non-stoichiometric (NST) and Mn doped KNN ceramics were prepared by conventional ceramic processing. Structure, microstructure and electrical properties were measured. It was observed that the window for mono-phasic compositions was very narrow for both NST ceramics and Mn doped ceramics. For NST ceramics the variation of A/B ratio influenced the polarization (P-E) hysteresis loop and better piezoelectric and dielectric responses could be found for small stoichiometry deviations (A/B = 0.97). Regarding Mn doping...

Extracting alpha from B0(d) --> K0 anti-K0 Decays

Datta, Alakabha; Imbeault, Maxime; London, David; Matias, Joaquim
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.33%
We propose a new method for obtaining the CP phase alpha, based on measurements of B0(d) --> K0 anti-K0, along with theoretical input. Due to the similarities of QCD factorization (QCDf) and perturbative QCD (pQCD), this input is basically the same for each of these models. Although the theoretical error is large at present, many of the contributing quantities will be better known in the future, leading to a smaller error. One outstanding question is the extent to which the precision on quark masses, especially m_c/m_b, can be improved. If one assumes that new physics is not present, the method can be used to predict the values of CP asymmetries in B0(d) --> K0 anti-K0: 0.02 <= A_{dir}^2 + A_{mix}^2 <= 0.125. A result outside this range would signal the existence of long-distance effects beyond those included in models of nonleptonic decays based on factorization (such as QCDf and pQCD), or the presence of new physics.; Comment: 5 pages, To appear in PRD

K0 meson physics in the gravitation field: a constraint on the equivalence principle

Karshenboim, Savely G.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 06/11/2008 Português
Relevância na Pesquisa
27.33%
K0-K0bar oscillations are extremely sensitive to the K0 and K0bar energy at rest. Even assuming m_K0=m_K0bar, the energy is not granted to be the same if gravitational effects on K0 and K0bar slightly differ. We consider various gravitation fields present and, in particular, galactic fields, which provide a negligible acceleration, but relatively large gravitational potential energy. A constraint from a possible effect of this potential energy on the kaon oscillations isfound to be |(m_g/m_i)_K0-(m_g/m_i)_K0bar| < 8 x 10^-13 atCL=90%. The derived constraint is competitive with other tests of universality of the free fall. Other applications are also discussed.

Measurement of the Time-Dependent CP Asymmetry in the B0 --> Phi K0 Decay

Aubert, B.; Collaboration, BABAR
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 15/03/2004 Português
Relevância na Pesquisa
27.33%
We present a measurement of the time-dependent CP asymmetry for the neutral B-meson decay B0 --> Phi K0. We use a sample of approximately 114 million B-meson pairs taken at the Upsilon(4S) resonance with the BaBar detector at the PEP-II B-meson Factory at SLAC. We reconstruct the CP eigenstates Phi K0_S and Phi K0_L where Phi --> K+ K-, K0_S --> pi+ pi-, and K0_L is observed via its hadronic interactions. The other B meson in the event is tagged as either a B0 or B0-bar from its decay products. The values of the CP-violation parameters are S = 0.47 +/- 0.34 (stat) +0.08/-0.06 (syst) and C = 0.01 +/- 0.33 (stat) +/- 0.10 (syst).; Comment: 7 pages, 2 postscript figures; submitted to Phys. Rev. Lett

Bs-->K+K- and Bs-->K0 anti-K0 Decays within Supersymmetry

Baek, Seungwon; London, David; Matias, Joaquim; Virto, Javier
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.33%
We compute the supersymmetric (SUSY) contributions to the observables in Bs-->K+K- and Bs-->K0 anti-K0 decays. The hadronic parameters in the standard-model (SM) amplitudes are obtained from the Bd-->K0 anti-K0 decay using a recent approach that combines flavor SU(3) symmetry and a controlled input from QCD factorization. The latest experimental data for BR(Bs-->K+K-) is in agreement with the SM prediction. We study how the branching ratios and the direct and mixing-induced CP asymmetries of both Bs-->KK decay modes are affected with the inclusion of SUSY, after imposing constraints from BR(B--> Xs gamma), B--> pi K and Delta Ms over the parameter space. While the branching ratios remain unaffected by SUSY, we identify the CP asymmetries of the Bs-->KK decays as the most promising observables to look for large deviations from the SM.; Comment: 16 pages, 4 figures. New comments and references added

Measurement of the Ratio of the Vector to Pseudoscalar Charm Semileptonic Decay Rate \Gamma(D+ > ANTI-K*0 mu+ nu)/\Gamma(D+ > ANTI-K0 mu+ nu)

The FOCUS Collaboration
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/06/2004 Português
Relevância na Pesquisa
27.33%
Using a high statistics sample of photo-produced charm particles from the FOCUS experiment at Fermilab, we report on the measurement of the ratio of semileptonic rates \Gamma(D+ > ANTI-K pi mu+ nu)/\Gamma(D+ > ANTI-K0 mu+ nu)= 0.625 +/- 0.045 +/- 0.034. Allowing for the K pi S-wave interference measured previously by FOCUS, we extract the vector to pseudoscalar ratio \Gamma(D+ > ANTI-K*0 mu+ nu)/\Gamma(D+ > ANTI-K0 mu+ nu)= 0.594 +/- 0.043 +/- 0.033 and the ratio \Gamma(D+ > ANTI-K0 mu+ nu)/\Gamma(D+ > K- pi+ pi+)= 1.019 +/- 0.076 +/- 0.065. Our results show a lower ratio for \Gamma(D > K* \ell nu})/\Gamma(D > K \ell nu) than has been reported recently and indicate the current world average branching fractions for the decays D+ >ANTI-K0(mu+, e+) nu are low. Using the PDG world average for B(D+ > K- pi+ pi+) we extract B(D+ > ANIT-K0 mu+ nu)=(9.27 +/- 0.69 +/- 0.59 +/- 0.61)%.; Comment: 15 pages, 1 figure

Novel Bell's inequalities for entangled K0 anti-K0 pairs

Bramon, A.; Garbarino, G.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.33%
We derive new Bell's inequalities for entangled K0 anti-K0 pairs. This requires 1) mutually exclusive setups allowing either K0 vs anti-K0 or KS vs KL detection and 2) the use of kaon regenerators. The inequalities turn out to be significantly violated by Quantum Mechanics, resulting in interesting tests of Local Realism at phi-factories and p anti-p machines.; Comment: 4 RevTeX pages; corrected typos; short comments added; accepted by Phys. Rev. Lett

Observation of B+ --> K0bar K+ and B0 --> K0 K0bar

The BABAR Collaboration; Aubert, B.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.33%
We report observations of the b --> d penguin-dominated decays B+ --> K0bar K+ and B0 --> K0 K0bar in approximately 350 million Upsilon(4S) --> BBbar decays collected with the BaBar detector. We measure the branching fractions B(B+ --> K0bar K+) = (1.61 +/- 0.44 +/- 0.09) * 10^-6 and B(B0 --> K0 K0bar) = (1.08 +/- 0.28 +/- 0.11) * 10^-6, and the CP-violating charge asymmetry A_{CP}(K0bar K+) = 0.10 +/- 0.26 +/- 0.03. Using a vertexing technique previously employed in several analyses of all-neutral final states containing kaons, we report the first measurement of time-dependent CP-violating asymmetries in B0 --> K0 K0bar, obtaining S = -1.28 +0.80/-0.73 +0.11/-0.16 and C = -0.40 +/- 0.41 +/- 0.06. We also report improved measurements of the branching fraction B(B+ --> K0 pi+) = (23.9 +/- 1.1 +/- 1.0) * 10^-6 and CP-violating charge asymmetry A_{CP}(K0 pi+) = -0.029 +/- 0.039 +/- 0.010.; Comment: 7 pages, 4 postscript figures. Published in Physical Review Letters. Minor changes in v2 to match the published version

Searching for the squark flavor mixing in CP violations of Bs -> K+ K- and K0bar K0 decays

Hayakawa, Atsushi; Shimizu, Yusuke; Tanimoto, Morimitsu; Yamamoto, Kei
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.39%
We study CP violations in the B_s-> K+K- and Bs->K0K0 decays in order to find the contribution of the supersymmetry, which comes from the gluino-squark mediated flavor changing current. We obtain the allowed region of the squark flavor mixing parameters by putting the experimental data, the mass difference Delta M_Bs, the CP violating phase phi_s in Bs to J/psi phi decay and the b to s gamma branching ratio. In addition to these data, we take into account the constraint from the asymmetry of B0->K+pi because the Bs->K+K- decay is related with the B0->K+pi- decay by replacing the spectator s with d. Under these constraints, we predict the magnitudes of the CP violation in the Bs->K+K- and Bs->K0K0 decays. The predicted region of the CP violation C_{K+K-} is strongly cut from the direct CP violation of barB0 to K-pi+, therefore, the deviation from the SM prediction of C_{K+K-} is not found. On the other hand, the CP violation S_{K+K-} is possibly deviated from the SM prediction considerably, in the region of 0.1- 0.5. Since the standard model predictions of C_{K0bar K0} and S_{K0bar K0} are very small, the squark contribution can be detectable in C_{K0bar K0} and S_{K0bar K0}. These magnitudes are expected in the region C_{K0bar K0}=-0.06-0.06 and S_{K0bar K0}=-0.5-0.3. More precise data of these CP violations provide us a crucial test for the gluino-squark mediated flavor changing current.; Comment: 20 pages...

Measurements of CP-Violating Asymmetries in the Decay B0-->K+K-K0

The BABAR Collaboration; Aubert, B.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.33%
We analyze the decay B0 --> K+ K- K0 using 383 million B-Bbar events collected by the BaBar detector at SLAC to extract CP violation parameter values over the Dalitz plot. Combining all K+ K- K0 events, we find A_CP = -0.015 +/- 0.077 +/- 0.053 and beta_eff = 0.352 +/- 0.076 +/- 0.026 rad, corresponding to a CP violation significance of 4.8 sigma. A second solution near pi/2 - beta_eff is disfavored with a significance of 4.5 sigma. We also report A_CP and beta_eff separately for decays to phi(1020) K0, f0(980) K0, and K+ K- K0 with m_{K+ K-} > 1.1 GeV/c^2.; Comment: 7 pages, 4 postscript figures; minor edits to reflect published version

Spin-Lattice Coupling in K0.8Fe1.6Se2 and KFe2Se2: Inelastic Neutron Scattering and ab-initio Phonon Calculations

Mittal, R.; Gupta, M. K.; Chaplot, S. L.; Zbiri, M.; Rols, S.; Schober, H.; Su, Y.; Brueckel, Th.; Wolf, T.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/01/2013 Português
Relevância na Pesquisa
27.33%
We report measurements of the temperature dependence of phonon densities of states in K0.8Fe1.6Se2 using inelastic neutron scattering technique. While cooling down to 150 K, a phonon peak splitting around 25 meV is observed and a new peak appears at 31 meV. The measurements support the recent Raman and infra-red measurements indicating a lowering of symmetry of K0.8Fe1.6Se2 upon cooling below 250 K. Ab-initio phonon calculations have been carried out for K0.8Fe1.6Se2 and KFe2Se2. The comparison of the phonon spectra as obtained from the magnetic as well as non magnetic calculations show pronounced differences. We show that in the two calculations the energy range of the vibrational contribution from both Fe and Se are quite different. We conclude that Fe magnetism is correlated to the phonon dynamics and it plays an important role in stabilizing the structure of K0.8Fe1.6Se2 as well as that of KFe2Se2. The calculations highlight the presence of low energy librational modes in K0.8Fe1.6Se2 as compared to KFe2Se2.; Comment: 22 pages, 3 Tables, 7 Figures

Investigation of the reaction pp->p K0 pi+ Lambda in search of the pentaquark

Nekipelov, M.; Buescher, M.; Hartmann, M.; Keshelashvili, I.; Kleber, V.; Koptev, V.; Maeda, Y.; Mikirtychiants, S.; Schleichert, R.; Sibirtsev, A.; Stroeher, H.; Valdau, Yu.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.33%
The reaction pp->p K0 pi+ Lambda has been studied with the ANKE spectrometer at COSY-Juelich at a beam momentum of 3.65 GeV/c in order to search for a possible signal of the pentaquark Theta+(1540), decaying into the p K0 system. By detecting four charged particles in the final state, the K0 and the Lambda have been reconstructed to tag strangeness production. It has been found that the pi+ Lambda missing-mass spectrum displays no significant signal expected from the Theta+(1540) excitation. The total cross section for the reaction pp->p K0 pi+ Lambda has been deduced, as well as an upper limit for the Theta+ production cross section. The intermediate Delta++ K0 Lambda state is found to provide a significant contribution to the reaction.; Comment: 10 pages, 7 figures; text changed, references added, style file changed

Search for the decay B0 --> K0_S K0_S K0_L

The BABAR Collaboration; Aubert, B.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.59%
We present the first search for the decay B0 --> K0_S K0_S K0_L using a data sample of 232 million B Bbar pairs. We find no statistically significant evidence for the non-resonant component of this decay. Our central value for the branching fraction, assuming the true Dalitz distribution is uniform and excluding the phi resonance, is B(B0 --> K0_S K0_S K0_L) = (2.4 +2.7 -2.5 +/- 0.6) x 10^{-6} where the errors are statistical and systematic, respectively. We set a single-sided Bayesian upper limit of B(B0 --> K0_S K0_S K0_L) < 7.4 x 10^{-6} at 90% confidence level using a uniform prior probability for physical values. Assuming the worst-case true Dalitz distribution, where the signal is entirely in the region of lowest efficiency, the 90% confidence level upper limit is B(B0 --> K0_S K0_S K0_L) < 16 x 10^{-6}.; Comment: Published version