Search for high-mass resonances decaying to emu in pp collisions at square root = 1.69 TeV.
Phys Rev Lett 96:21 (2006) 211802
Abstract:
We describe a general search for resonances decaying to a neutral emu final state in pp collisions at a center-of-mass energy of 1.96 TeV. Using a data sample representing 344 pb(-1) of integrated luminosity recorded by the Collider Detector at Fermilab II experiment, we compare standard model predictions with the number of observed events for invariant masses between 50 and 800 GeV/c2. Finding no significant excess (5 events observed vs 7.7 +/- 0.8 expected for M(emu) > 100 GeV/c2 ), we set limits on sneutrino and Z' masses as functions of lepton family number violating couplings.Measurement of bottom-quark hadron masses in exclusive J/psi decays with the CDF detector.
Phys Rev Lett 96:20 (2006) 202001
Abstract:
We measure the masses of b hadrons in exclusively reconstructed final states containing a J/psi --> mu-mu+ decay using 220 pb(-1) of data collected by the CDF II experiment. We find: m(B+) = 5279.10 +/- 0.41(stat.) +/- 0.36(sys.) MeV/c2, m(B0) = 5279.63 +/- 0.53(stat.) +/- 0.33(sys.) MeV/c2, m(B(s)0) = 5366.01 +/- 0.73(stat.) +/- 0.33(sys.) MeV/c2, m(lambda(b)0) = 5619.7 +/- 1.2(stat.) +/- 1.2(sys.) MeV/c2. m(B+) - m(B0) = -0.53 +/- 0.67(stat.) +/- 0.14(sys.) MeV/c2, m(B(s)0) - m(B0) = 86.38 +/- 0.90(stat.) +/- 0.06(sys.) MeV/c2, m(lambda(b)0) - m(B0) = 339.2 +/- 1.4(stat.) +/- 0.1(sys.) MeV/c2. The measurements of the B(s)0, lambda(b)0 mass, m(B(s)0) - m(B0) and m(lambda(b)0) - m(B0) mass difference are of better precision than the current world averages.Measurement of the top quark mass with the dynamical likelihood method using lepton plus jets events with b-tags in pp̄ collisions at s=1.96TeV
Physical Review D Particles Fields Gravitation and Cosmology 73:9 (2006)
Abstract:
This paper describes a measurement of the top quark mass, Mtop, with the dynamical likelihood method (DLM) using the CDF II detector at the Fermilab Tevatron. The Tevatron produces top/antitop (tt̄) pairs in pp̄ collisions at a center-of-mass energy of 1.96 TeV. The data sample used in this analysis was accumulated from March 2002 through August 2004, which corresponds to an integrated luminosity of 318pb-1. We use the tt̄ candidates in the "lepton+jets" decay channel, requiring at least one jet identified as a b quark by finding a displaced secondary vertex. The DLM defines a likelihood for each event based on the differential cross section as a function of Mtop per unit phase space volume of the final partons, multiplied by the transfer functions from jet to parton energies. The method takes into account all possible jet combinations in an event, and the likelihood is multiplied event by event to derive the top quark mass by the maximum likelihood method. Using 63 tt̄ candidates observed in the data, with 9.2 events expected from background, we measure the top quark mass to be 173.2+2.6-2.4(stat.)±3. 2(syst.)GeV/c2, or 173.2+4.1-4.0GeV/c2. © 2006 The American Physical Society.Search for pair production of second generation scalar leptoquarks in p over(p, ̄) collisions at sqrt(s) = 1.96 TeV
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 636:3-4 (2006) 183-190
Abstract:
We report on a search for the pair production of second generation scalar leptoquarks ( LQ2) in p over(p, ̄) collisions at the center-of-mass energy sqrt(s) = 1.96 TeV, using data corresponding to an integrated luminosity of 294 ± 19 pb-1 recorded with the DØ detector. No evidence for a leptoquark signal in the LQ2 over(LQ, -)2 → μ q μ q channel has been observed, and upper bounds on the product of cross section times branching fraction were set. This yields lower mass limits of mLQ2 > 247 GeV / c2 for β = B ( LQ2 → μ q ) = 1 and mLQ2 > 182 GeV / c2 for β = 1 / 2. Combining these limits with previous DØ results, the lower limits on the mass of a second generation scalar leptoquark are mLQ2 > 251 GeV / c2 and mLQ2 > 204 GeV / c2 for β = 1 and β = 1 / 2, respectively. © 2006 Elsevier B.V. All rights reserved.Observation of muon neutrino disappearance with the MINOS Detectors in the NuMI Neutrino Beam
Physical Review Letters 97 (2006) 191801 4pp