Combination of t(t)over-bar cross section measurements and constraints on the mass of the top quark and its decays into charged Higgs bosons

We combine measurements of the top quark pair production cross section in p (p) over bar collisions in the l + jets, ll, and tau l final states ( where l is an electron or muon) at a center of mass energy of root s = 1.96 TeV in 1 fb(-1) of data collected with the D0 detector. For a top quark mass of 170 GeV/c(2), we obtain sigma(t (t) over bar) = 8.18(-0.87)(+0.98) pb in agreement with the theoretical prediction. Based on predictions from higher order quantum chromodynamics, we extract a mass for the top quark from the combined t (t) over bar cross section, consistent with the world average of the top quark mass. In addition, the ratios of t (t) over bar cross sections in different final states are used to set upper limits on the branching fractions B(t -> H(+)b -> tau(+) vb) and B(t -> H(+)b -> c (s) over barb) as a function of the charged Higgs boson mass.

Charged three-body system with arbitrary masses near conformal invariance

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Search for Long-Lived Charged Massive Particles with the D0 Detector

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Challenging the weak cosmic censorship conjecture with charged quantum particles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Search for Doubly Charged Higgs Boson Pair Production in p(p)over-bar Collisions at root s=1.96 TeV

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Search for Charged Massive Long-Lived Particles

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for heavy stable charged particles in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dependence on pseudorapidity and on centrality of charged hadron production in PbPb collisions at root s(NN)=2.76 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Forward energy flow, central charged-particle multiplicities, and pseudorapidity gaps in W and Z boson events from pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Study of high-p(T) charged particle suppression in PbPb compared to pp collisions at root s(NN)=2.76 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Shape, transverse size, and charged-hadron multiplicity of jets in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Study of the inclusive production of charged pions, kaons, and protons in pp collisions at root s=0.9, 2.76, and 7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of jet fragmentation into charged particles in pp and PbPb collisions at root s(NN)=2.76 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Scaling investigation for the dynamics of charged particles in an electric field accelerator

Some dynamical properties of an ensemble of trajectories of individual (non-interacting) classical particles of mass m and charge q interacting with a time-dependent electric field and suffering the action of a constant magnetic field are studied. Depending on both the amplitude of oscillation of the electric field and the intensity of the magnetic field, the phase space of the model can either exhibit: (i) regular behavior or (ii) a mixed structure, with periodic islands of regular motion, chaotic seas characterized by positive Lyapunov exponents, and invariant Kolmogorov-Arnold-Moser curves preventing the particle to reach unbounded energy. We define an escape window in the chaotic sea and study the transport properties for chaotic orbits along the phase space by the use of scaling formalism. Our results show that the escape distribution and the survival probability obey homogeneous functions characterized by critical exponents and present universal behavior under appropriate scaling transformations. We show the survival probability decays exponentially for small iterations changing to a slower power law decay for large time, therefore, characterizing clearly the effects of stickiness of the islands and invariant tori. For the range of parameters used, our results show that the crossover from fast to slow decay obeys a power law and the behavior of survival orbits is scaling invariant. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4772997]

Effect of citrate ions on the electrochemical behaviour of low-carbon steel in borate buffer solutions

The electrochemical behaviour of cold-rolled low carbon steel was studied on both active and passive potential regions in borate buffer solutions with and without the addition of sodium citrate (NaCit). In the active region anodic charges increased significantly and RCT values decreased with citrate, due to the formation of soluble complexes. In the passive potential region the film formed at +0.4 V in borate buffer solution with and without 0.010 M NaCit is probably enriched by Fe3O4 oxide, while films formed at +0.8 V are probably enriched by gamma-Fe2O3. The equivalent circuit [R-s(R(CT)Q)] fitted all experimental impedance data. (C) 2003 Elsevier Ltd. All rights reserved.