EPJ

2023 Impact factor 4.2
EPJ C - Particles and Fields
Particles and Fields
Eur. Phys. J. C 8, 559-571
DOI 10.1007/s100529900014

Bose-Einstein Correlations in $\rm e^+e^-\rightarrow W^+W^-$ at 172
and 183 GeV

The OPAL Collaboration

G. Abbiendi2 - et al.

2Dipartimento di Fisica dell' Università di Bologna and INFN, I-40126 Bologna, Italy

Received: 28 October 1998 / Published online: 1 March 1999

Abstract
Bose-Einstein correlations between like-charge pions are studied in hadronic final states produced by \ensuremath{\mathrm{e}^+\mathrm{e}^-}annihilations at center-of-mass energies of 172 and 183 GeV. Three event samples are studied, each dominated by one of the processes $\mathrm{W}^+\mathrm{W}^-\rightarrow\mathrm{q\overline{q}}\ell \overline{\nu}_{\ell}$,$\mathrm{W}^+\mathrm{W}^- \rightarrow\mathrm{q\overline{q}}\mathrm{q\overline{q}}$,or $(\mathrm{Z}^0/\gamma)^{*}\rightarrow\mathrm{q\overline{q}}$. After demonstrating the existence of Bose-Einstein correlations in W decays, an attempt is made to determine Bose-Einstein correlations for pions originating from the same W boson and from different W bosons, as well as for pions from $(\mathrm{Z}^0/\gamma)^{*}\rightarrow\mathrm{q\overline{q}}$events. The following results are obtained for the individual chaoticity parameters $\lambda$, assuming a common source radius R:

\begin{eqnarray} \lambda^{\mathrm{ same}} & = & 0.63 \pm 0.19 \pm 0.14 \nonumber... ...onumber ,\\ R\, & = & 0.92\pm0.09\pm 0.09 \ \mathrm{fm} \nonumber.\end{eqnarray}
In each case, the first error is statistical and the second is systematic. At the current level of statistical precision it is not established whether Bose-Einstein correlations, between pions from different W bosons exist or not.

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