Measurement of the forward-backward asymmetries of $e^ + e^- \rightarrow Z \rightarrow b \overline{b}$ and $e^ + e^- \rightarrow Z \rightarrow c \overline{c}$ using prompt leptons
| Autor: | Nektarios Benekos, Clara Troncon, Danielle Moraes, Sigve Haug, ALBERTO DE MIN, Nathalie Besson, Krzysztof Doroba, David Rodriguez Gonzalez, Filipe Veloso, Anna Lipniacka, Tommaso Tabarelli de Fatis, Lorenzo Vitale, Giuseppe Della Ricca, Francisco Javier Cuevas Maestro, Klaus Moenig, Maurizio Bonesini, Paolo Morettini, Mattias Ellert, Mariusz Witek, Barbara De Lotto, Oxana Smirnova, Philip Allport, Clara Matteuzzi, Pawel Bruckman de Renstrom, William Murray, Antonio Ferrer, Borut Kersevan, Ivo Van Vulpen, Nuno Castro, Daniel Jeans, Alessandro De Angelis, Bernardo Tomé, Andre Sopczak, Costa Mezquita, Agnieszka Zalewska, Ulrich Schwickerath, Markus Elsing, Bjarne Stugu, Javier Fernandez Menendez, Valerio Verzi, Jiri Chudoba, Andrei Sadovskiy, Katarzyna Grzelak, Tomasz Szumlak, Themistocles Bowcock, Piotr Zalewski, Mario Pimenta, Jesus Marco de Lucas, Carmen Garcia, Luiz Mundim, Nuno Anjos, Rupert Leitner, Leandro De Paula, Marco Paganoni, Patrice Verdier, Michal Bluj, Chris Parkes, Francisco Matorras, Alessandro Petrolini, Patrícia Gonçalves, Jan Ridky, Guillelmo Gomez-Ceballos, Petr Travnicek, Tadeusz Lesiak, Pedro T. Abreu, Arantza Oyanguren, Nicola Amapane, Christian Weiser, Jiri Rames |
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| Rok vydání: | 2004 |
| Předmět: |
Semileptonic decay
Physics Particle physics Physics and Astronomy (miscellaneous) 010308 nuclear & particles physics Electron–positron annihilation Hadron Weinberg angle Charge (physics) 01 natural sciences Bottom quark Charm quark 0103 physical sciences 010306 general physics Engineering (miscellaneous) Lepton |
| Zdroj: | The European Physical Journal C. 34:109-125 |
| ISSN: | 1434-6052 1434-6044 |
| Popis: | The forward-backward asymmetries of the processes $e^+e^- \rightarrow Z \rightarrow b \overline{b}$ and $e^+e^- \rightarrow Z \rightarrow c \overline{c}$ were measured from a sample of hadronic Zdecays collected by the DELPHI experiment between 1993 and 1995. Enriched samples of $b\bar{b}$ and $c\bar{c}$ events were obtained using lifetime information. The tagging of b and c quarks in these samples was based on the semileptonic decay channels $b/c \rightarrow X + \mu $ and $ b/c \rightarrow X + e $ combined with charge flow information from the hemisphere opposite to the lepton. Combining the $A_{\mathrm{FB}}^{\mathrm{b\overline{\mathrm{b}}}}$ and $A_{\mathrm{FB}}^{\mathrm{c\overline{\mathrm{c}}}}$ measurements presented in this paper with published results based on 1991 and 1992 DELPHI data samples, the following pole asymmetries were obtained: \begin{displaymath}\mbox{$A_{\mathrm{FB}}^{\mathrm{0, b}}$}= 0.1021 \pm 0.0052 \mathrm{~(stat)} \pm 0.0024 \mathrm{~(syst)} \end{displaymath} \begin{displaymath}\mbox{$A_{\mathrm{FB}}^{\mathrm{0, c}}$}= 0.0728 \pm 0.0086 \mathrm{~(stat)} \pm 0.0063 \mathrm{~(syst)}\end{displaymath} The effective value of the weak mixing angle derived from these measurements is \begin{displaymath}\mbox{$\sin ^2 \theta_{\mathrm{W,eff}}^{\mathrm{lept}}$}= 0.23170 \pm 0.00097 .\end{displaymath} |
| Databáze: | OpenAIRE |
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