A measurement of the inclusive production of π^0 mesons in hadronic Z decays is presented and compared to Monte Carlo model predictions. The analysis is based on approximately 2 million hadronic events recorded with the ALEPH detector at... more
A measurement of the inclusive production of π^0 mesons in hadronic Z decays is presented and compared to Monte Carlo model predictions. The analysis is based on approximately 2 million hadronic events recorded with the ALEPH detector at LEP at a centre-of-mass energy of s=91.2~\rmGeV. Neutral pions are reconstructed using photons measured in the electromagnetic calorimeter and photons from conversion pairs. The inclusive π^0 momentum spectrum is measured in the range 0.025<x_p=p/p_beam<1. In this range the ...
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Single W production is studied in the data recorded with the ALEPH detector at LEP at centre-of-mass energies between 161 and 183GeV. The cross section is measured to be σW= 0.41±0.17 (stat.)±0.04 (syst.) pb at 183GeV, consistent with the... more
Single W production is studied in the data recorded with the ALEPH detector at LEP at centre-of-mass energies between 161 and 183GeV. The cross section is measured to be σW= 0.41±0.17 (stat.)±0.04 (syst.) pb at 183GeV, consistent with the Standard Model expectation. Limits on non-standard WWγ couplings are deduced as− 1.6< κ γ< 1.5 (λ γ= 0) and− 1.6< λ γ< 1.6 (κ γ= 1) at 95% CL A search for effectively invisible decays of the W boson in W pair production is performed, leading to an upper limit on the branching ratio ...
The data collected at a centre-of-mass energy of 188.6 GeV by ALEPH at LEP, corresponding to an integrated luminosity of 173.6 pb− 1, are analysed in a search for the scalar partners of quarks and leptons predicted in supersymmetric... more
The data collected at a centre-of-mass energy of 188.6 GeV by ALEPH at LEP, corresponding to an integrated luminosity of 173.6 pb− 1, are analysed in a search for the scalar partners of quarks and leptons predicted in supersymmetric models. No evidence for any such particles was found in the decay channels ℓ ̃→ ℓχ, t ̃→ c χ, t ̃→ b ℓ ν ̃, b ̃→ b χ, and q ̃→ q χ. Improved mass lower limits have been obtained in the framework of the Minimal Supersymmetric Standard Model.
Searches for neutral Higgs bosons are performed with the 237 pb− 1 of data collected in 1999 by the ALEPH detector at LEP, for centre-of-mass energies between 191.6 and 201.6 GeV. These searches apply to Higgs bosons within the context of... more
Searches for neutral Higgs bosons are performed with the 237 pb− 1 of data collected in 1999 by the ALEPH detector at LEP, for centre-of-mass energies between 191.6 and 201.6 GeV. These searches apply to Higgs bosons within the context of the Standard Model and its minimal supersymmetric extension (MSSM) as well as to invisibly decaying Higgs bosons. No evidence of a signal is seen. A lower limit on the mass of the Standard Model Higgs boson of 107.7 GeV/c2 at 95% confidence level is set. In the MSSM, lower limits of 91.2 ...