Search for heavy Majorana neutrinos in mu(+/-)mu(+/-) + jets and e(+/-)e(+/-) + jets events in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Heavy-flavor tagging and the supersymmetry reach of the CERN Large Hadron Collider

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

Scaling and universality in two dimensions: three-body bound states with short-ranged interactions

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

Light-Front model of transition form-factors in heavy meson decay

Electroweak transition form factors of heavy meson decays are important ingredients in the extraction of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements from experimental data. In this work, within a. light-front framework, we calculate electroweak transition form factor for the semileptonic decay of D mesons into a pion or a kaon. The model results underestimate in both cases the new data of CLEO for the larger momentum transfers accessible in the experiment. We discuss possible reasons for that in order to improve the model.

Search for a heavy gauge boson W ' in the final state with an electron and large missing transverse energy in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for a heavy neutral gauge boson in the dielectron channel with 5.4 fb(-1) of p(p)over-bar collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for heavy, top-like quark pair production in the dilepton final state in pp collisions at. root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Description of Heavy Quark Mass by Lippmann-Schwinger Equation

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

Search for a heavy bottom-like quark in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of detector motion in Bell inequalities with entangled fermions

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

Searching for squeezed particle-antiparticle correlations in high-energy heavy-ion collisions

Squeezed correlations of particle-antiparticle pairs were predicted to exist if the hadron masses were modified in the hot and dense medium formed in high-energy heavy-ion collisions. Although well-established theoretically, they have not yet been observed experimentally. We suggest here a clear method to search for such a signal by analyzing the squeezed correlation functions in terms of measurable quantities. We illustrate this suggestion for simulated phi phi pairs at the Relativistic Heavy Ion Collider (RHIC) energies.

Search for W ' bosons decaying to an electron and a neutrino with the D0 detector

This Letter describes the search for a new heavy charged gauge boson W-' decaying into an electron and a neutrino. The data were collected with the D0 detector at the Fermilab Tevatron p (p) over bar Collider at root s=1.96 TeV, and correspond to an integrated luminosity of about 1 fb(-1). Lacking any significant excess in the data in comparison with known processes, an upper limit is set on sigma(')(W)xB(W-'-> e nu), and a W-' boson with mass below 1.00 TeV can be excluded at the 95% C.L., assuming standard-model-like couplings to fermions. This result significantly improves upon previous limits and is the most stringent to date.

Light composite Higgs from an effective action for technicolor

We compute an effective action for a composite Higgs boson formed by new fermions belonging to a general technicolor non-Abelian gauge theory, using a quite general expression for the fermionic self-energy that depends on a certain parameter (alpha), that defines the technicolor theory from the extreme walking behavior up to the one with a standard operator product expansion behavior. We discuss the values of the trilinear and quadrilinear scalar couplings. Our calculation spans all the possible physical possibilities for mass and couplings of the composite system. In the case of extreme walking technicolor theories we verify that it is possible to have a composite Higgs boson with a mass as light as the present experimental limit, contrary to the usual expectation of a heavy mass for the composite Higgs boson. In this case we obtain an upper limit for the Higgs boson mass, (M(H)<= O(700) GeV for SU(2)(TC)), and the experimental data on the Higgs boson mass constrain SU(N)(TC) technicolor gauge groups to be smaller than SU(10)(TC).

Search for W ' boson resonances decaying to a top quark and a bottom quark

We search for the production of a heavy W ' gauge boson that decays to third generation quarks in 0: 9 fb(-1) of p (p) over bar collisions at root s = 1: 96 TeV, collected with the D0 detector at the Fermilab Tevatron collider. We find no significant excess in the final-state invariant mass distribution and set upper limits on the production cross section times branching fraction. For a left-handed W ' boson with SM couplings, we set a lower mass limit of 731 GeV. For right-handed W ' bosons, we set lower mass limits of 739 GeV if the W ' boson decays to both leptons and quarks and 768 GeV if the W ' boson decays only to quarks. We also set limits on the coupling of the W ' boson to fermions as a function of its mass.

Squeezed K+K- correlations in high energy heavy ion collisions

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)