Search for technicolor particles produced in association with a W Boson at CDF.
Phys Rev Lett 104:11 (2010) 111802
Abstract:
We present a search for the technicolor particles rho{T} and pi_{T} in the process pp-->rho{T}-->Wpi{T} at a center of mass energy of sqrt[s]=1.96 TeV. The search uses a data sample corresponding to approximately 1.9 fb{-1} of integrated luminosity accumulated by the CDF II detector at the Fermilab Tevatron. The event signature we consider is W-->lnu and pi{T}-->bb, bc or bu depending on the pi{T} charge. We select events with a single high-p{T} electron or muon, large missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with multiple b-tagging algorithms. The observed number of events and the invariant mass distributions are consistent with the standard model background expectations, and we exclude a region at 95% confidence level in the rho{T}-pi{T} mass plane. As a result, a large fraction of the region m(rho{T})=180-250 GeV/c{2} and m(pi{T})=95-145 GeV/c{2} is excluded.Measurement of absolute branching fractions of inclusive semileptonic decays of charm and charmed-strange mesons
Physical Review D Particles Fields Gravitation and Cosmology 81:5 (2010)
Abstract:
We have measured the inclusive semileptonic branching fractions of D0, D+, and Ds+ mesons. For these measurements, we have used the full CLEO-c open-charm data samples, 818pb-1 at ECM=3.774GeV, giving D0D虅0 and D+D- events, and 602pb -1 at ECM=4.170GeV, giving Ds*卤Ds" events. We obtain B(D0鈫扻别+谓e)=(6.46卤0.09卤0.11)%, B(D +鈫扻别+谓e)=(16.13卤0.10卤0.29)%, and B(Ds+鈫扻别+谓e)=(6.52卤0.39卤0.15)%, where the first uncertainties are statistical and the second are systematic. From these and lifetimes obtained elsewhere, we obtain the ratios of semileptonic decay widths 螕(D+鈫扻别+谓e)/螕(D0鈫扻别 +谓e)=0.985卤0.015卤0.024 and 螕(Ds+鈫扻别 +谓e)/螕(D0鈫扻别+谓e)=0.828卤0. 051卤0.025. The ratio of D+ and D0 is consistent with the isospin symmetry prediction of unity, and the ratio of Ds+ and D0 differs from unity, as expected. 漏 2010 The American Physical Society.51猎奇入口ing the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron
(2010)
51猎奇入口ing the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron
ArXiv 1003.3146 (2010)
Abstract:
We study the underlying event in proton-antiproton collisions by examining the behavior of charged particles (transverse momentum pT > 0.5 GeV/c, pseudorapidity |\eta| < 1) produced in association with large transverse momentum jets (~2.2 fb-1) or with Drell-Yan lepton-pairs (~2.7 fb-1) in the Z-boson mass region (70 < M(pair) < 110 GeV/c2) as measured by CDF at 1.96 TeV center-of-mass energy. We use the direction of the lepton-pair (in Drell-Yan production) or the leading jet (in high-pT jet production) in each event to define three regions of \eta-\phi space; toward, away, and transverse, where \phi is the azimuthal scattering angle. For Drell-Yan production (excluding the leptons) both the toward and transverse regions are very sensitive to the underlying event. In high-pT jet production the transverse region is very sensitive to the underlying event and is separated into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The data are corrected to the particle level to remove detector effects and are then compared with several QCD Monte-Carlo models. The goal of this analysis is to provide data that can be used to test and improve the QCD Monte-Carlo models of the underlying event that are used to simulate hadron-hadron collisions.51猎奇入口 of the associated production of photons and b-quark jets in pp虅 collisions at 鈭歴=1.96TeV
Physical Review D - Particles, Fields, Gravitation and Cosmology 81:5 (2010)