A new measurement of the branching ratio of K(S) → γ γ
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 493:1-2 (2000) 29-35
Abstract:
The decay rate of K(S) → γγ has been measured with the NA48 detector at the CERN SPS. A total of 149 K(S) → γγ events have been observed. The branching ratio is determined to be (2.58 ± 0.36(stat) ± 0.22(sys)) x 10-6. (C) 2000 Elsevier Science B.V.Measurement of the W boson mass using large rapidity electrons
Physical Review D - Particles, Fields, Gravitation and Cosmology 62:9 (2000) 1-33
Abstract:
We present a measurement of the W boson mass using data collected by the DØ experiment at the Fermilab Tevatron during 1994-1995. We identify W bosons by their decays to ev final states where the electron is detected in a forward calorimeter. We extract the W boson mass MW by fitting the transverse mass and transverse electron and neutrino momentum spectra from a sample of 11 089 W→ev decay candidates. We use a sample of 1687 dielectron events, mostly due to Z→ee decays, to constrain our model of the detector response. Using the forward calorimeter data, we measure MW=80.691±0.227 GeV. Combining the forward calorimeter measurements with our previously published central calorimeter results, we obtain MW=80.482 ±0.091 GeV. ©2000 The American Physical Society.Search for new physics in aμX data at DØ using SLEUTH: A quasi-model-independent search strategy for new physics
Physical Review D - Particles, Fields, Gravitation and Cosmology 62:9 (2000) 1-19
Abstract:
We present a quasi-model-independent search for the physics responsible for electroweak symmetry breaking. We define final states to be studied, and construct a rule that identifies a set of relevant variables for any particular final state. A new algorithm ("SLEUTH") searches for regions of excess in those variables and quantifies the significance of any detected excess. After demonstrating the sensitivity of the method, we apply it to the semi-inclusive channel eμX collected in 108 pb-1 of pp̄ collisions at √s=1.8 TeV at the DØ experiment during 1992-1996 at the Fermilab Tevatron. We find no evidence of new high pT physics in this sample. ©2000 The American Physical Society.Direct measurement of the W Boson width in pp̄ collisions at √s = 1.8 TeV
Physical Review Letters 85:16 (2000) 3347-3352
Abstract:
The W boson width, ΓW obtained in studies of the transverse-mass spectra of leptonic W decays is measured. Through analysis, the W width is determined from a binned log-likelihood fit to the transverse-mass distribution in the region 100 < MT < 200 GeV. Including previously published computational fluid dynamics (CDF) electron result with the same common error yields ΓW = 2.05 ± 0.10(stat) ± 0.08(syst) GeV.Measurement of J/psi and psi(2S) polarization in pp collisions at sqrt[s] = 1.8 TeV.
Phys Rev Lett 85:14 (2000) 2886-2891
Abstract:
We have measured the polarization of J/psi and psi(2S) mesons produced in pp collisions at sqrt[s] = 1.8 TeV, using data collected at the Collider Detector at Fermilab during 1992-1995. The polarization of promptly produced J/psi [psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5]