The branching ratio for the leptonic decay of charged B mesons (B- --> tau (-)<(<nu>)over bar>(tau)) has been measured using selected leptonic tau (-) --> l(-)nu ...(tau)<(<nu>)over bar>(l) and hadronic tau (-) --> nu X-tau decays in Z --> b (b) over bar dec
A study of b semileptonic decays into D, D pi(+/-) and D*pi(+/-) final states is presented. The D-0, D+ and D*(+) mesons are exclusively reconstructed in Z decay data recorded from 1992 to 1995 in ...the DELPHI experiment at LEP. The overall branching fracti
A test of the QED process e(+)e(-) --> gamma gamma>(*) over bar *(gamma) is reported. The data analysed were collected with the DELPHI detector in 1998 and 1999 at the highest energies achieved ...at LEP, reaching 202 GeV in the centre-of-mass. The total int
Observation is made of rapidity-alignment of \KK and \pp pairs which results from their asymmetric orientation in rapidity, with respect to the direction from primary quark to antiquark. The \KK and ...\pp data are consistent with predictions from the fragmentation string model. However, the \pp data strongly disagree with the conventional implementation of the cluster model. The non-perturbative process of `gluon splitting to diquarks' has to be incorporated into the cluster model for it to agree with the data. Local conservation of \pT between particles nearby in rapidity (i.e., \pT compensation) is analysed with respect to the thrust direction for \pipix, \KKx, and \pp pairs. In this case, the string model provides fair agreement with the data. The cluster model is incompatible with the data for all three particle pairs. The model with its central premiss of isotropically-decaying clusters predicts a \pT correlation not seen in the data.
Data collected at the Z resonance using the DELPHI detector at LEP are used to determine the charged hadron multiplicity in gluon and quark jets as a function of a transverse momentum-like scale. The ...colour factor ratio, C-A/C-F, is directly observed in t
Searches for pair production of gauginos and squarks in $e^{+} e^{-}$ collisions at a centre-of-mass energy of 189 GeV have been performed on data corresponding to an integrated luminosity of 158 ...pb$^{-1}$ collected by the DELPHI detector at LEP. The data were analyzed under the assumption of non-conservation of \mbox{$R$-parity} through a single dominant $\bar{U} \bar{D} \bar{D}$~coupling between squarks and quarks. Typical final states contain between 4 and 10 jets with or without additional leptons. No excess of data above Standard Model expectations was observed. The results were used to constrain domains of the MSSM parameter space and derive limits on the masses of supersymmetric particles. The following mass limits at 95\% CL were obtained from these searches: \begin{itemize} \item neutralino mass: $m_{\tilde{\chi^0_{1}}} \ge 32$ GeV \item chargino mass: $m_{\tilde{\chi^+_{1}}} \ge 94 $ GeV \item stop and sbottom mass (indirect decay) with $\Delta M 5$ GeV: $m_{\tilde{t_{1}}} \ge 74$ GeV, for $\Phi_{mix}=0$ rad $m_{\tilde{t_{1}}} \ge 59$ GeV, for $\Phi_{mix}=0.98 $ rad $m_{\tilde{b_{1}}} \ge 72$ GeV, for $\Phi_{mix}=0$ rad. \end{itemize} The angle $\phi_{mix}$ is the mixing angle between left and right handed quarks.
A search for unstable heavy fermions with the DELPHI detector at LEP is reported. Sequential and non-canonical leptons, as well as excited leptons and quarks, are considered. The data analysed ...correspond to an integrated luminosity of about 48 pb(-1) at a
The data collected by DELPHI in 1996 have been used to measure the average charged particle multiplicities and dispersions in q (q) over bar events at centre-of-mass energies of root s = 161 GeV and ...root s = 172 GeV, and the average charge multiplicity in
The hadronic structure of the decay of the tau lepton to three charged particles, tau --> 3 pi nu(tau), is studied using data collected by the DELPHI detector at LEP between 1992 and 1995. The ...invariant mass of the 3 pi system, m(3 pi), is fitted using th
The total and the differential cross-sections for the reaction e(+)e(-) --> gamma gamma(gamma) have been measured with the DELPHI detector at LEP at centre-of-mass energies from 130 to 183 GeV for ...an integrated luminosity of 78.19 pb(-1). The results agre
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