0000000000134532
AUTHOR
B. Åsman
showing 5 related works from this author
Search for Z0 decays to two leptons and a charged particle-antiparticle pair
1993
Based on a sample equivalent to 365 000 hadronic Z0 decays, the search in DELPHI data for pairs of leptons accompanied by a pair of charged particles is described. A total of 11 events were found in the electron channel, 9 in the muon channel and 7 in the tau channel. Results on lepton pairs with a radiated photon are also presented. The data from all channels are compatible with the expectations from standard processes. However, one event was found in the tau channel with an unusually high mass of the charged particle pair.
Updated precision measurement of the average lifetime of B hadrons
1996
The measurement of the average lifetime of B hadrons using inclusively reconstructed secondary vertices has been updated using both an improved processing of previous data and additional statistics from new data. This has reduced the statistical and systematic uncertainties and gives \tau_{\mathrm{B}} = 1.582 \pm 0.011\ \mathrm{(stat.)} \pm 0.027\ \mathrm{(syst.)}\ \mathrm{ps.} Combining this result with the previous result based on charged particle impact parameter distributions yields \tau_{\mathrm{B}} = 1.575 \pm 0.010\ \mathrm{(stat.)} \pm 0.026\ \mathrm{(syst.)}\ \mathrm{ps.}
A measurement of the mean lifetimes of charged and neutral B-hadrons
1993
The decays of B-hadrons have been reconstructed using the charged particles recorded in the DELPHI silicon microstrip detector. The sum of the charges of the secondaries determines the charge of the B-hadron parent. Some 232 114 multihadronic Z0 decays recorded during the 1991 run of LEP at centre-of-mass energies between 88.2 GeV and 94.2 GeV yield 253 B-hadron candidates with well-measured charge. From these the mean lifetimes of neutral and charged B-hadrons are found to be 1.44 +/- 0.21(stat.) +/- 0.14(syst.) ps and 1.56 +/- 0.19(stat.) +/- 0.13(syst.) ps respectively. The ratio of their lifetimes is 1.09(-0.23)+0.28 (Stat.) +/- 0.11 (syst.). Under some assumptions on the abundance and …
Measurement of the transverse spin correlation in Z → τ+ τ- decays
1997
The measurement of the correlation between the transverse spin components of tau(+)tau(-) pairs collected during 1992 to 1994 with the DELPHI detector at LEP1 is presented. A value C-TT = 0.87 +/- 0.20 (stat.)(-0.12)(+0.10) (syst.) was obtained for the correlation parameter, in agreement with the Standard Model expectation. (C) 1997 Published by Elsevier Science B.V.
A Search for Heavy Stable and Long-Lived Squarks and Sleptons in $e^+ e^-$ Collisions at Energies from 130 to 183 GeV
1998
A search for stable and long-lived heavy charged particles used the data taken by the DELPHI experiment at energies from 130 to 183 GeV. The Cherenkov light detected in the Ring Imaging Cherenkov Detector and the ionization loss measured in the Time Projection Chamber identify heavy particles from masses of 2 to nearly 89 GeV/c$^2$. Upper limits are given on the production cross-section and masses of sleptons, free squarks with a charge of $q = \pm 2/3e$ and hadronizing squarks. A search for stable and long-lived heavy charged particles used the data taken by the DELPHI experiment at energies from 130 to 183 GeV. The Cherenkov light detected in the Ring Imaging Cherenkov Detector and the io…