J. A. Benitez

Double parton interactions in {gamma}+3 jet events in pp collisions at {radical}(s)=1.96 TeV

We have used a sample of gamma + 3 jets events collected by the D0 experiment with an integrated luminosity of about 1 fb(-1) to determine the fraction of events with double parton scattering (f(DP ...

Search for CP violation in B{sub s}{sup 0{yields}{mu}+}D{sub s}{sup -}X decays in pp collisions at {radical}(s)=1.96 TeV

We have performed a search for CP violation in a sample of Bs0→μ+Ds-X decays corresponding to 5 fb-1 of proton-antiproton collisions collected by the D0 detector in Run II at the Fermilab Tevatron Collider. New physics in Bs0 mixing could contribute a significant CP violating weak phase, which would be observed as a difference in the decay-time distribution for Bs0→B s0 oscillated states versus that for B s0→Bs0. A fit to the decay-time distributions of the Bs0/B s0 candidates yields the flavor-specific asymmetry afss=[-1.7±9.1(stat)-1.5+1.4(syst)]×10-3, which excludes CP violation due to new physics within the experimental sensitivity.We have performed a search for CP violation in a sample of B{sub s}{sup 0{yields}{mu}+}D{sub s}{sup -}X decays corresponding to 5 fb{sup -1} of proton-antiproton collisions collected by the D0 detector in Run II at the Fermilab Tevatron Collider. New physics in B{sub s}{sup 0} mixing could contribute a significant CP violating weak phase, which would be observed as a difference in the decay-time distribution for B{sub s}{sup 0{yields}}B{sub s}{sup 0} oscillated states versus that for B{sub s}{sup 0{yields}}B{sub s}{sup 0}. A fit to the decay-time distributions of the B{sub s}{sup 0}/B{sub s}{sup 0} candidates yields the flavor-specific asymmetry a{sub fs}{sup s}=[-1.7{+-}9.1(stat){sub -1.5}{sup +1.4}(syst)]x10{sup -3}, which excludes CP violation due to new physics within the experimental sensitivity.

Evidence for the Decay B{sub s}{sup 0}{yields}D{sub s}{sup (*)}D{sub s}{sup (*)} and a Measurement of {delta}{gamma}{sub s}{sup CP}/{gamma}{sub s}

We search for the semi-inclusive process B{sub s}{sup 0}{yields}D{sub s}{sup (*)}D{sub s}{sup (*)} using 2.8 fb{sup -1} of pp collisions at {radical}(s)=1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We observe 26.6{+-}8.4 signal events with a significance above background of 3.2 standard deviations yielding a branching ratio of B(B{sub s}{sup 0}{yields}D{sub s}{sup (*)}D{sub s}{sup (*)})=0.035{+-}0.010(stat.){+-}0.011(syst.). Under certain theoretical assumptions, these double-charm final states saturate CP-even eigenstates in the B{sub s}{sup 0} decays resulting in a width difference of {delta}{gamma}{sub s}{sup CP}/{gamma}{sub s}=0.072{+-}0.021(stat.){+-}0.022(syst.)

Measurement of the Angular and Lifetime Parameters of the Decays B{sub d}{sup 0}{yields}J/{psi}K*{sup 0} and B{sub s}{sup 0}{yields}J/{psi}{phi}

We present measurements of the linear polarization amplitudes and the strong relative phases that describe the flavor-untagged decays B{sub d}{sup 0}{yields}J/{psi}K*{sup 0} and B{sub s}{sup 0}{yields}J/{psi}{phi} in the transversity basis. We also measure the mean lifetime {tau}{sub s} of the B{sub s}{sup 0} mass eigenstates and the lifetime ratio {tau}{sub s}/{tau}{sub d}. The analyses are based on approximately 2.8 fb{sup -1} of data recorded with the D0 detector. From our measurements of the angular parameters we conclude that there is no evidence for a deviation from flavor SU(3) symmetry for these decays and that the factorization assumption is not valid for the B{sub d}{sup 0}{yields}J/{psi}K*{sup 0} decay.

Search for Pair Production of Doubly Charged Higgs Bosons in the H{sup ++}H{sup --}{yields}{mu}{sup +}{mu}{sup +}{mu}{sup -}{mu}{sup -} Final State

We report the results of a search for pair production of doubly charged Higgs bosons via pp{yields}H{sup ++}H{sup --}X{yields}{mu}{sup +}{mu}{sup +}{mu}{sup -}{mu}{sup -}X at {radical}(s)=1.96 TeV. We use a data set corresponding to an integrated luminosity of 1.1 fb{sup -1} collected from 2002 to 2006 by the D0 detector at the Fermilab Tevatron Collider. In the absence of an excess above the standard model background, lower mass limits of M(H{sub L}{sup {+-}}{sup {+-}})>150 GeV/c{sup 2} and M(H{sub R}{sup {+-}}{sup {+-}})>127 GeV/c{sup 2} at 95% C.L. are set, respectively, for left-handed and right-handed doubly charged Higgs bosons assuming a 100% branching ratio into muons.

Measurement of the Electron Charge Asymmetry in pp{yields}W+X{yields}e{nu}+X Events at {radical}(s)=1.96 TeV

We present a measurement of the electron charge asymmetry in p (p) over bar -> W + X -> e nu + X events at a center of mass energy of 1.96 TeV using 0.75 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron Collider. The asymmetry is measured as a function of the electron transverse momentum and pseudorapidity in the interval (-3.2, 3.2) and is compared with expectations from next-to-leading order calculations in perturbative quantum chromodynamics. These measurements will allow more accurate determinations of the proton parton distribution functions.

Measurement of B{sub s}{sup 0} Mixing Parameters from the Flavor-Tagged Decay B{sub s}{sup 0}{yields}J/{psi}{phi}

From an analysis of the flavor-tagged decay \bsdec we obtain the width difference between the

ZZ{yields}l{sup +}l{sup -}{nu}{nu} production in pp collisions at {radical}(s)=1.96 TeV

B_s^0

Study of the Decay B{sub s}{sup 0}{yields}D{sub s}{sup (*)}D{sub s}{sup (*)}

light and heavy mass eigenstates,

Search for B{sub s}{sup 0}{yields}{mu}{sup +}{mu}{sup -} decays at D0

\Delta \Gamma_s \equiv \Gamma_L - \Gamma_H = 0.19 \pm 0.07 {\rm (stat)}\thinspace ^{+0.02}_{-0.01} {\rm (syst)}