Search for new physics in high-mass electron-positron events in pp[over] collisions at square root s = 1.96 TeV.
Phys Rev Lett 99:17 (2007) 171802
Abstract:
We report the results of a search for a narrow resonance in electron-positron events in the invariant mass range of 150-950 GeV/c(2) using 1.3 fb(-1) of pp[over] collision data at square root s = 1.96 TeV collected by the CDF II detector at Fermilab. No significant evidence of such a resonance is observed and we interpret the results to exclude the standard-model-like Z' with a mass below 923 GeV/c(2) and the Randall-Sundrum graviton with a mass below 807 GeV/c(2) for k/M[over](pl) = 0.1, both at the 95% confidence level. Combining with diphoton data excludes the Randall-Sundrum graviton for masses below 889 GeV/c(2) for k/M[over](pl) = 0.1.Measurement of the top quark mass in the dilepton channel
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 655:1-2 (2007) 7-14
Abstract:
We present a measurement of the top quark mass in the dilepton channel based on approximately 370 pb-1 of data collected by the DØ experiment during Run II of the Fermilab Tevatron collider. We employ two different methods to extract the top quark mass. We show that both methods yield consistent results using ensemble tests of events generated with the DØ Monte Carlo simulation. We combine the results from the two methods to obtain a top quark mass mt = 178.1 ± 8.2 GeV. The statistical uncertainty is 6.7 GeV and the systematic uncertainty is 4.8 GeV. © 2007 Elsevier B.V. All rights reserved.Searches for direct pair production of supersymmetric top and supersymmetric bottom quarks in pp̄ collisions at s=1.96TeV
Physical Review D - Particles, Fields, Gravitation and Cosmology 76:7 (2007)
Abstract:
We search for direct pair production of supersymmetric top quarks and supersymmetric bottom quarks in proton-antiproton collisions at s=1.96TeV, using 295pb-1 of data recorded by the Collider Detector at Fermilab (CDF II) experiment. The supersymmetric top (supersymmetric bottom) quarks are selected by reconstructing their decay into a charm (bottom) quark and a neutralino, which is assumed to be the lightest supersymmetric particle. The signature of such processes is two energetic heavy-flavor jets and missing transverse energy. The number of events that pass our selection for each search process is consistent with the expected standard model background. By comparing our results to the theoretical production cross sections of the supersymmetric top and supersymmetric bottom quarks in the minimal supersymmetric standard model, we exclude, at a 95% confidence level in the frame of that model, a supersymmetric top quark mass up to 132GeV/c2 for a neutralino mass of 48GeV/c2, and a supersymmetric bottom quark mass up to 193GeV/c2 for a neutralino mass of 40GeV/c2. © 2007 The American Physical Society.Properties of L=1 B1 and B2* mesons
Physical Review Letters 99:17 (2007)
Abstract:
This Letter presents the first strong evidence for the resolution of the excited B mesons B1 and B2* as two separate states in fully reconstructed decays to B+(*)Ï€-. The mass of B1 is measured to be 5720.6Â.±2.4Â.±1.4Â.€‰Â.€ ‰MeV/c2 and the mass difference Î"M between B2* and B1 is 26.2Â.±3.1Â.±0. 9Â.€‰Â.€‰MeV/c2, giving the mass of the B2* as 5746.8Â.±2.4Â.±1. 7Â.€‰Â.€‰MeV/c2. The production rate for B1 and B2* mesons is determined to be a fraction (13.9Â.±1. 9Â.±3.2)% of the production rate of the B+ meson. © 2007 The American Physical Society.Measurement of the pp̄→tt̄ production cross section and the top quark mass at s=1.96TeV in the all-hadronic decay mode
Physical Review D - Particles, Fields, Gravitation and Cosmology 76:7 (2007)