By Alessandro De Angelis and Reynald Pain
[astro-ph/0205059] (May 2002)
By Alessandro De Angelis
[astro-ph/0112371] (Dec 2001)
By A. De Angelis and L. Vitale
Nucl.Phys. 92 (2001) 259.
By A. De Angelis, R. Giannitrapani, A. Brunengo, E. Guardincerri, M.G. Pia, A.S. Howard, F. Longo, R. Nartallo, P. Nieminen, A. Pfeiffer, G. Santin
In *Beijing 2001, CHEP* 341.
By Alessandro de Angelis
[astro-ph/0009271] UDPHIR-00-02-AA (Sep 2000)
By M. David, A. Maio, A. de Angelis, A. Gomes
In *Lisbon 2000, Advanced Monte Carlo for radiation physics, particle transport simulation and applications* 1181.
By Alessandro de Angelis
In *Osaka 2000, High energy physics
Abstract - During 1997, 1998 and 1999 the DELPHI detector at LEP has collected data at centre-of-mass energies between 183 GeV and 200 GeV. We have used these data to measure the average charged particle multiplicity in e+e- -> b-bbar events, n_bb, and the difference deltabl between n_bb and the multiplicity, n_ll, in generic light quark (u,d,s) events. The result is remarkably in agreement with QCD predictions, while it is inconsistent with calculations assuming that the multiplicity accompanying the decay of a heavy quark is independent of the mass of the quark itself.
Abstract - Inclusive distributions of charged particles in W decays are experimentally investigated using the statistics collected by the DELPHI experiment at LEP during 1997, 1998 and 1999, at center-of-mass energies from 183 to 200 GeV. The possible effects of interconnections between the hadronic decays of two W are discussed.
Abstract - To estimate the strength of the Bose-Einstein correlations and the radius of the hadronization region in multiparticle production, the two-particle correlation functions R for identical pairs is adjusted to a parametric function describing the enhancement at small momentum differences. This is usually done by means of a binned uncorrelated least squares fit. This article demonstrates that this procedure underestimates the statistical errors. A recipe is given to construct from the data the covariance matrix between the bins of the histogram of the two-particle correlation function.
Abstract - The photon radiation in the initial state lowers the energy available for the e$^+$e$^-$ collisions; this effect is particularly important at LEP2 energies (above the mass of the Z boson). Being aligned to the beam direction, such initial state radiation is mostly undetected. This article describes the procedure used by the DELPHI experiment at LEP to estimate the effective centre-of-mass energy in hadronic events collected at energies above the Z peak. Typical resolutions ranging from 2 to 3 GeV on the effective center-of-mass energy are achieved, depending on the event topology.
Abstract - Interactions between the products of the hadronic decays of different Ws in WW pair events can occur at several stages: from the colour rearrangement between the quarks coming from the primary branching, to the gluon exchange during the parton cascade, to the mixing of identical pions due to Bose-Einstein correlations. Besides the intrinsic interest of their study related to the understanding of the multiparticle production mechanisms, these phenomena can affect the ultimate accuracy in the W mass measurement by LEP 2. The status of the experimental analysis on interconnection effects between W pairs hadronically decaying is reviewed in this paper.
Abstract - The DELPHI detector at LEP is particularly suited for hadron identification and for the identification of b-initiated jets. This note presents recent results based on such characteristics.
Abstract - The correlation functions R for like-sign and unlike-sign particle pairs were measured for fully hadronic and for mixed decay WW channels using the data collected by the DELPHI detector at LEP at center-of-mass energy between 183 and 200 GeV. The correlation functions for particle pairs in $q\bar{q}$ events at high energy were also measured.
Abstract - In high energy reactions, the creation of rapidly moving charges is accompanied by a soft final state radiation. Experimental measurements performed up to now give contradictory results. The study of the radiation associated with the creation of charged particles in the decay of Z bosons could clarify the situation. Such radiation could be detectable in DELPHI.
Mail to alessandro.de.angelis@cern.ch