52 research outputs found
Determination of sin2 θeff w using jet charge measurements in hadronic Z decays
The electroweak mixing angle is determined with high precision from measurements of the mean difference between forward and backward hemisphere charges in hadronic decays of the Z. A data sample of 2.5 million hadronic Z decays recorded over the period 1990 to 1994 in the ALEPH detector at LEP is used. The mean charge separation between event hemispheres containing the original quark and antiquark is measured for bb̄ and cc̄ events in subsamples selected by their long lifetimes or using fast D*'s. The corresponding average charge separation for light quarks is measured in an inclusive sample from the anticorrelation between charges of opposite hemispheres and agrees with predictions of hadronisation models with a precision of 2%. It is shown that differences between light quark charge separations and the measured average can be determined using hadronisation models, with systematic uncertainties constrained by measurements of inclusive production of kaons, protons and A's. The separations are used to measure the electroweak mixing angle precisely as sin2 θeff w = 0.2322 ± 0.0008(exp. stat.) ±0.0007(exp. syst.) ± 0.0008(sep.). The first two errors are due to purely experimental sources whereas the third stems from uncertainties in the quark charge separations
Measurement of the spin-rotation parameter, beta, in the reaction pi+ p ---> K+ sigma+ at 1.60-GeV/c and 1.88-GeV/c
Differential cross section and polarisation for π+p→K+Σ+ at 26 momenta between 1.282 and 2.473 GeV/c
DIFFERENTIAL CROSS-SECTION AND POLARIZATION FOR pi+ p ---> K+ SIGMA+ AT 26 MOMENTA BETWEEN 1.282-GeV/c AND 2.473-GeV/c
AN ENERGY DEPENDENT PARTIAL WAVE ANALYSIS OF pi+ p ---> K+ SIGMA+ BETWEEN THRESHOLD AND 2.35-GeV
A MEASUREMENT OF THE PI+ P ---> K+ SIGMA+ DIFFERENTIAL CROSS-SECTION AND POLARIZATION BETWEEN 1.27-GEV/C AND 2.50-GEV/C. (TALK)
A MEASUREMENT OF THE PI+ P BACKWARD ELASTIC DIFFERENTIAL CROSS-SECTION USING THE RUTHERFORD MULTIPARTICLE SPECTROMETER. (TALK)
A MEASUREMENT OF pi+ p BACKWARD ELASTIC DIFFERENTIAL CROSS-SECTIONS FROM 1.282-GeV/c TO 2.472-GeV/c
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