Learn More
A search has been performed for the Standard Model Higgs boson in the data sample collected with the ALEPH detector at LEP, at centre-of-mass energies up to 209 GeV. An excess of 3 σ beyond the background expectation is found, consistent with the production of the Higgs boson with a mass near 114 GeV/c 2. Much of this excess is seen in the four-jet(More)
The cross sections and forward-backward asymmetries of hadronic and leptonic events produced in e + e − collisions at centre-of-mass energies from 130 to 183 GeV are presented. Results for e + e − , µ + µ − , τ + τ − , q¯ q, b ¯ b and c¯ c production show no significant deviation from the Standard Model predictions. This enables constraints to be set upon(More)
This Technical Design Report is dedicated to Tom Ypsilantis. Tom conceived the Ring Imaging Cherenkov detectors for particle identification in LHCb and he made an inestimable contribution to the LHCb RICH project. Tom would have wished to see these detectors in operation. He was totally dedicated to the project. He will be missed by the RICH group for his(More)
KLOE has measured most decay branching ratios of K S , K L and K ±-mesons. It has also measured the K L and the K ± lifetime and determined the shape of the form factors involved in kaon semileptonic decays. We present in the following a description of the above measurements and a well organized compendium of all of our data, with particular attention to(More)
— We describe the KLOE detector at DAΦNE, the Frascati φ–factory, and its physics program. We begin with a brief description of the detector design and operation. Kaon physics is a major topic of investigation with KLOE thanks in part to the unique availability of pure KS,KL, K ± beams at a φ–factory. We have measured all significant branching ratios of all(More)
The rate of gluon splitting into c¯ c pairs in hadronic Z decays is measured using the data sample collected by ALEPH from 1991 to 1995. The selection is based on the identification of leptons (electrons and muons) originating from semileptonic charm decays, and on the topological properties of signal events. The result derived from the selected sample is g(More)
Hadronic Z decays into three jets are used to test QCD models of colour reconnection (CR). A sensitive quantity is the rate of gluon jets with a gap in the particle rapidity distribution and zero jet charge. Gluon jets are identified by either energy-ordering or by tagging two b-jets. The rates predicted by two string-based tunable CR models, one(More)
The four-jet nal state is analyzed to search for hadronic decays of pair-produced heavy particles. The analysis uses the ALEPH data collected at LEP in November 1995 at centre-of-mass energies of 130 and 136 GeV, corresponding to a total integrated luminosity of 5.7 pb ?1. An excess of four-jet events is observed with respect to the standard model(More)
Hadronic Z decay data taken with the ALEPH detector at LEP1 are used to measure the three-jet rate as well as moments of various event-shape variables. The ratios of the observables obtained from b-tagged events and from an inclusive sample are determined. The mass of the b quark is extracted from a fit to the measured ratios using a next-to-leading order(More)
In the fixed energy environment of the e + e − collider DAΦNE, KLOE can measure the cross section of the process e + e − → hadrons as a function of the hadronic system energy using the radiative return method. At energies below 1 GeV, e + e − → ρ → π + π − is the dominating hadronic process. We report here on the status of the analysis of the process e + e(More)