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)

Ratios of dijet production cross sections as a function of the absolute difference in rapidity between jets in proton-proton collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for electroweak production of charginos and neutralinos using leptonic final states in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Observation of Z decays to four leptons with the CMS detector at the LHC

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of the relative prompt production rate of chi(c2) and chi(c1) in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of the pp(-)-> W gamma plus X cross section at root s=1.96 TeV and WW gamma anomalous coupling limits

The WWγ triple gauge boson coupling parameters are studied using pp̄rarr; νγ+X(=e,μ) events at s=1.96 TeV. The data were collected with the D0 detector from an integrated luminosity of 162pb-1 delivered by the Fermilab Tevatron Collider. The cross section times branching fraction for pp̄→W(γ)+X→ νγ+X with ETγ>8 GeV and ΔR γ> 0.7 is 14.8±1.6(stat)±1.0(syst) ±1.0(lum)pb. The one-dimensional 95% confidence level limits on anomalous couplings are -0.88<Δκγ<0.96 and -0. 20<λγ<0.20. © 2005 The American Physical Society.

Measurement of the tt̄ production cross section in pp̄ collisions at √s = 1.96 TeV in dilepton final states

We present a measurement of the top quark pair (tt̄) production cross section in pp̄ collisions at √s=1.96 TeV using events with two charged leptons in the final state. This analysis utilizes an integrated luminosity of 224-243 pb-1 collected with the DØ detector at the Fermilab Tevatron Collider. We observe 13 events in the e+e -, eμ and μ+μ- channels with an expected background of 3.2±0.7 events. For a top quark mass of 175 GeV, we measure a tt̄ production cross section of σtt̄=8. 6-2.7 +3.2(stat)±1.1(syst)±0.6(lumi) pb, consistent with the standard model prediction. © 2005 Elsevier B.V. All rights reserved.

Search for Randall-Sundrum gravitons with 1 fb(-1) of data from p(p)over-bar collisions at root s=1.96 TeV

We search for decays of Kaluza-Klein excitations of the graviton in the Randall-Sundrum model of extra dimensions to e+e- and in 1 fb-1 of pp collisions at s=1.96 TeV collected by the D0 detector at the Fermilab Tevatron. We set 95% confidence level upper limits on the production cross section times branching fraction, which translate into lower limits on the mass of the lightest excitation between 300 and 900 GeV for values of the coupling k/M Pl between 0.01 and 0.1. © 2008 The American Physical Society.

Study of direct CP violation in B±→J/ ψK±(π±) decays

We present a search for direct CP violation in B±→J/ ψK±(π±) decays. The event sample is selected from 2.8fb-1 of pp̄ collisions recorded by D0 experiment in run II of the Fermilab Tevatron Collider. The charge asymmetry ACP(B+→J/ψK+)=+0.0075±0. 0061(stat)±0.0030(syst) is obtained using a sample of approximately 40000 B±→J/ψK± decays. The achieved precision is of the same level as the expected deviation predicted by some extensions of the standard model. We also measured the charge asymmetry ACP(B+→J/ψπ+)=-0. 09±0.08(stat)±0.03(syst). © 2008 The American Physical Society.

First study of the radiation-amplitude zero in W gamma production and limits on anomalous WW gamma couplings at root s=1.96 TeV

We present results from a study of pp̄→Wγ+X events utilizing data corresponding to 0.7fb-1 of integrated luminosity at s=1.96TeV collected by the D0 detector at the Fermilab Tevatron Collider. We set limits on anomalous WWγ couplings at the 95% C.L. The one-dimensional 95% C.L. limits are 0.49<κγ<1.51 and -0.12<λγ<0.13. We make the first study of the charge-signed rapidity difference between the lepton and the photon and find it to be indicative of the standard model radiation-amplitude zero in the Wγ system. © 2008 The American Physical Society.

Observation of the Bc meson in the exclusive decay Bc→J/ψπ

A fully reconstructed Bc→J/ψπ signal is observed with the D0 detector at the Fermilab Tevatron pp̄ collider using 1.3fb-1 of integrated luminosity. The signal consists of 54±12 candidates with a significance that exceeds 5 standard deviations, and confirms earlier observations of this decay. The measured mass of the Bc meson is 6300±14(stat)±5(syst) MeV/c2. © 2008 The American Physical Society.

Search for decay of a fermiophobic higgs boson hf→ y y with the D0 detector at s=1.96a TeV

We report the results of a search for a narrow resonance decaying into two photons in 1.1fb-1 of data collected by the D0 experiment at the Fermilab Tevatron Collider during the period 20022006. We find no evidence for such a resonance and set a lower limit on the mass of a fermiophobic Higgs boson of mhf>100GeV at the 95% C.L. This exclusion limit exceeds those obtained in previous searches at the Fermilab Tevatron and covers a significant region of the parameter space B(hf→I I ) vs mhf which was not accessible at the CERN Large Electron-Positron Collider. © 2008 The American Physical Society.

Measurement of the inclusive jet cross section in pp̄ collisions at s=1.96TeV

We report on a measurement of the inclusive jet cross section in pp̄ collisions at a center-of-mass energy s=1.96TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider corresponding to an integrated luminosity of 0.70fb-1. The data cover jet transverse momenta from 50 to 600 GeV and jet rapidities in the range -2.4 to 2.4. Detailed studies of correlations between systematic uncertainties in transverse momentum and rapidity are presented, and the cross section measurements are found to be in good agreement with next-to-leading order QCD calculations. © 2008 The American Physical Society.