Measurement of the fraction of hadronic Z decays into charm quark pairs

• Main Authors: BARATE, R., THULASIDAS, M.
• Format: text
• Language: English
• Published: Institutional Knowledge at Singapore Management University 1998
• Subjects: Computer Sciences; Databases and Information Systems
• Online Access: https://ink.library.smu.edu.sg/sis_research/5846; https://ink.library.smu.edu.sg/context/sis_research/article/6849/viewcontent/CM_P00068167.pdf
• Institution: Singapore Management University

The full statistics of hadronic Z decays collected with the ALEPH detector are analysed to measure, by three methods, the ratio, RcRc, of the partial decay width of the Z into cc¯cc¯ quarks to the total hadronic width. One method uses the inclusive pp and p⊥p⊥ spectra of electrons. The other two use a double-tagging technique to measure RcRc independently of the charm-tagging efficiency. In one, the tagging procedure uses the reconstruction of high momentum charmed mesons (D∗+D∗+, D+D+ and \({\rm D^0}$) to detect the charm quarks. In the other, a charm quark is tagged from the D∗D∗'s reconstructed in the D∗+→π+D0D∗+→π+D0 decay channel and the other from the slow pion from the D∗−→π−D¯0D∗−→π−D¯0 decay. The combination of these measurements leads to Rc=Γ(Z→cc¯)/Γ(Z→hadrons))=0.1681±0.0054(stat)±0.0062(syst)Rc=Γ(Z→cc¯)/Γ(Z→hadrons))=0.1681±0.0054(stat)±0.0062(syst).