Search for Bs 0 - Bs 0 oscillations and a measurement of Bd 0 - Bd 0 oscillations using events with an inclusively reconstructed vertex: The Delphi collaboration
European Physical Journal C 28:2 (2003) 155-173
Abstract:
Neutral B meson oscillations in the Bs0 - Bs0 and Bd0 - Bd0 systems were studied using a sample of about 4.0 million hadronic Z decays recorded by the DELPHI detector between 1992 and 2000. Events with a high transverse momentum lepton were removed and a sample of 770 k events with an inclusively reconstructed vertex was selected. The mass difference between the two physical states in the Bd0 - Bs0 system was measured to be: Δmd = (0.531 = 0.025(stat.) ± 0.007(syst.))ps-1. The following limit on the width difference of these states was also obtained: |ΔΓBd|/ΓBd < 0.18 at 95% CL. As no evidence for Bs0 - Bs0 oscillations was found, a limit on the mass difference of the two physical states was given: Δms > 5.0 ps-1 at 95% CL. The corresponding sensitivity of this analysis is equal to 6.6 ps-1.Search for resonant ν̃ production at √s = 183 to 208 GeV: The DELPHI collaboration
European Physical Journal C 28:1 (2003) 15-26
Abstract:
Searches for resonant ν̃ production in e+e- collisions under the assumption that R-parity is not conserved and that the dominant R-parity violating coupling is λ121m or λ131 used data recorded by DELPHI in 1997 to 2000 at centre-of-mass energies of 183 to 208 GeV. No deviation from the Standard Model was observed. Upper limits are given for the λ121 and λ131 couplings as a function of the sneutrino mass and total width. The limits are especially stringent for sneutrino masses equal to the centre-of-mass energies with the highest integrated luminosities recorded.The ηc (2980) formation in two-photon collisions at LEP energies
European Physical Journal C 31:4 (2003) 481-489
Abstract:
ηc(2980) production in γγ interactions has been detected via its decays into Ks0K±π ∓, K+K-K+K- and K +K-π+π- in the data taken with the DELPHI detector at LEP1 and LEP2 energies. The two-photon radiative width averaged over all observed decay channels is Γγγ = 13.9 ± 2.0 (stat.) ± 1.4(syst.) ± 2.7 (BR) keV. No direct decay channel ηc → π+π -π+π- has been observed. An upper limit Γγγ < 5.5 keV at 95% confidence level has been evaluated for this decay mode.A measurement of the branching fractions of the b-quark into charged and neutral b-hadrons
PHYSICS LETTERS B 576:1-2 (2003) 29-42
A study of the energy evolution of event shape distributions and their means with the DELPHI detector at LEP
EUROPEAN PHYSICAL JOURNAL C 29:3 (2003) 285-312