Search for long-lived neutral particles decaying to quark-antiquark pairs in proton-proton collisions at root s=8 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Study of vector boson scattering and search for new physics in events with two same-sign leptons and two jets

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for a standard model-like Higgs boson in the mu(+)mu(-) and e(+)e(-) decay channels at the LHC

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Soft edge of hadron scattering and minijet models for the total and inelastic pp cross sections at LHC and beyond

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

Search for vector-like T quarks decaying to top quarks and Higgs bosons in the all-hadronic channel using jet substructure

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for disappearing tracks in proton-proton collisions at root s=8 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurements of differential and double-differential Drell-Yan cross sections in proton-proton collisions at root s=8 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for standard model production of four top quarks in the lepton plus jets channel in pp collisions at root S=8 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Searches for heavy Higgs bosons in two-Higgs-doublet models and for t→ch decay using multilepton and diphoton final states in pp collisions at 8 TeV

Searches are presented for heavy scalar (H) and pseudoscalar (A) Higgs bosons posited in the two doublet model (2HDM) extensions of the standard model (SM). These searches are based on a data sample of pp collisions collected with the CMS experiment at the LHC at a center-of-mass energy of root s = 8 TeV and corresponding to an integrated luminosity of 19.5 fb(-1). The decays H -> hh and A -> Zh, where h denotes an SM-like Higgs boson, lead to events with three or more isolated charged leptons or with a photon pair accompanied by one or more isolated leptons. The search results are presented in terms of the H and A production cross sections times branching fractions and are further interpreted in terms of 2HDM parameters. We place 95% C.L. cross section upper limits of approximately 7 pb on sigma B for H -> hh and 2 pb for A -> Zh. Also presented are the results of a search for the rare decay of the top quark that results in a charm quark and an SM Higgs boson, t -> ch, the existence of which would indicate a nonzero flavor-changing Yukawa coupling of the top quark to the Higgs boson. We place a 95% C.L. upper limit of 0.56% on B(t -> ch).

Measurement of pseudorapidity distributions of charged particles in proton-proton collisions at root s=8 TeV by the CMS and TOTEM experiments

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of a Z+(1540) resonance on K+N scattering

The impact of a (I=0, JP=1/2+)Z+(1540) resonance with a width of 5 MeV or more on the K+N(I=0) elastic cross section and on the P01 phase shift is examined within the KN meson-exchange model of the Jülich group. It is shown that the rather strong enhancement of the cross section caused by the presence of a Z + with the above properties is not compatible with the existing empirical information on KN scattering. Only a much narrower Z+ state could be reconciled with the existing data - or, alternatively, the Z + state must lie at an energy much closer to the KN threshold.

Anomalous couplings in e(+)e(-)->W+W- gamma at CERN LEP 2 and NLC

We present sensitivity limits on the coefficients of a dimension-6 effective Lagrangian that parametrizes the possible effects of new physics beyond the standard model. Our results are based on the study of the process e(+)e(-)-->W+W- y at CERN LEP 2 and NLC energies. In our calculations, we include all the new anomalous interactions, involving vectors and Higgs bosons, and take into account the standard model irreducible background. We analyze the impact of these new interactions on the total cross section. including the effects of the initial electron and final W polarizations. We then focus on the operators that will not be constrained by the e(+)e(-)-->W+W- process, obtaining limits based on the photon energy distribution.

Effect of Er:YAG laser on CaF2 formation and its anticariogenic action on human enamel: An in vitro study

Objective: The objective of this study was to evaluate the effect of Er: YAG laser on the formation of CaF2, after the application of acidulated phosphate fluoride (APF), and its influence on the anti-cariogenic action in human dental enamel. Background Data: Er:YAG laser was designed to promote ablation of the enamel. However, the possibility of using this energy to increase the enamel's resistance to caries has hardly been explored, and neither has its interaction with the use of fluorides. Materials and Methods: One hundred and twenty blocks of enamel were allocated to four groups of 30 blocks each: (1) C, control group; (2) Er:YAG, laser; (3) APF; and (4) Er:YAG+APF. Of these, 80 blocks were submitted to pH cycling for 14 days. In the other 40 blocks, fluoride (CaF2) was measured before cycling. After pH cycling, surface microhardness (SMH), microhardness in cross-section (converted to mineral contents % vol. min.), and fluoride after cycling (40 blocks) were also determined. Results: SMH decreased in all groups. The control group showed the highest decrease, and Er:YAG+APF showed the lowest decrease (p < 0.05). Groups APF and Er:YAG showed the same results (p > 0.05). Mineral content at depths 10, 20, and 40 μm was lower in the control and Er:YAG groups, and higher in groups APF and Er:YAG+APF. CaF2 (μgF/cm2) deposited before pH cycling was higher in the APF group when compared to the Er:YAG+APF group. Control and Er:YAG groups showed the lowest values (p > 0.05). Conclusion: It was concluded that Er:YAG laser influenced the deposition of CaF2 on the enamel and showed a superficial anti-cariogenic action, but not in depth.

Efeito túnel multidimensional em reações nucleares

Pós-graduação em Física - IFT

Lorentz violation bounds on Bhabha scattering

We investigate the effect of Lorentz-violating terms on Bhabha scattering in two distinct cases correspondent to vectorial and axial nonminimal couplings in quantum electrodynamics ( QED). In both cases, we find significant modifications with respect to the usual relativistic result. Our results reveal an anisotropy of the differential cross section which implies new constraints on the possible Lorentz-violating terms.