A test of the QED process \eeintogg(\fot) is reported. The data analysed were collected with the DELPHI detector in 1998 and 1999 at the highest ener\-gies achieved at LEP, reaching 202 GeV in the ...centre-of-mass. The total integrated luminosity amounts to 375.7 pb$^{-1}$. The differential and total cross-sections for the process $e^+e^- \to \gamma \gamma$ were measured, and found to be in agreement with the QED prediction. 95\% Confidence Level (C.L.) lower limits on the QED cut-off parameters of $\rm \Lambda_+ $ 330 GeV and $\rm \Lambda_{-}>$ 320 GeV were derived. A 95\% C.L. lower bound on the mass of an excited electron of 311 $\rm GeV/c^2$ (for $\lambda_{\gamma}$ =1) was obtained. s-channel virtual graviton exchange was searched for, resulting in 95\% C.L. lower limits on the string mass scale, $\rm M_S$: $\rm M_S 713 \, GeV/c^2$ ( $\lambda=1$) and $\rm M_S 691 \,GeV/c^2$ ($\lambda = -1$).
A search for the supersymmetric partner of the goldstino, the sgoldstino S, at LEP2 is presented. The production S gamma followed by S decay into two gluons or into two photons was studied at 189-202 ...GeV LEP centre-of-mass energies. No evidence for the S
The longitudinal polarization of the Lambda(b) baryon is measured at the LEP e(+)e(-) collider by DELPHI. It is determined from the charged lepton and neutrino energy spectra in 249 +/- 19 Lambda(b) ...semileptonic decays reconstructed in approximate to 3.5
Searches for resonant (ν) over tilde production in e(+)e(-) collisions under the assumption that R-parity is not conserved and that the dominant R-parity violating coupling is lambda(121) or ...lambda(131) 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 lambda(121) and lambda(131) 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.
A search for pair-produced charged Higgs bosons was performed in the high energy data collected by the DELPHI detector at LEP II at centre-of-mass energies from 189 GeV to 202 GeV. The three ...different final states, taunutaunu, c (s) over bar(c) over bars and c (s) over bar taunu were considered. New methods were applied to reject wrong hadronic jet pairings and for the tau identification, where a discriminator based on tau polarisation and polar angles was used. No excess of data compared to the expected Standard Model processes was observed and the existence of a charged Higgs boson with mass lower than 71.5 GeV/c(2) is excluded at the 95% confidence level. (C) 2002 Published by Elsevier Science B.V.
Oscillations of B-s(0) mesons have been studied in samples selected from about 3.5 million hadronic Z decays detected by DELPHI between 1992 and 1995. One analysis uses events in the exclusive decay ...channels: B-s(0) --> D(s)(-)pi (+) or D(s)(-)a(1)(+) and
Searches for pair production of supersymmetric particles under the assumption that R-parity is not conserved are presented, based on data recorded by the DELPHI detector in 1998 from e(+)e(-) ...collisions at a centre-of-mass energy of 189 GeV. Only one R-pa
The rate Z --> b (b) over bar b (b) over bar was measured using about 2 x 10(6) hadronic decays collected by the DELPHI experiment in 1994 and 1995. Events were forced into 3-jets with y(min) > ...0.06 and a b-tag was required for every jet. The rate was mea
DELPHI results are presented on the inclusive production of the neutral mesons rho(0), f(0)(980), f(2)(1270), K-2(*0)(1430) and f'(2)(1525) in hadronic Z(0) decays. They are based on about 2 million ...multihadronic events collected in 1994 and 1995, using t
The partial decay width R-c of the Z into c (c) over bar quark pair and the number of charm quarks n(c) per b decay are measured with the DELPHI detector at LEP 1. Particle identification provides ...clear DO, D+, D-s(+) and Lambda(c)(+) signatures. The char
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