We use the transverse momentum spectrum of leptons in the decay chain t --> bW with W --> l nu to measure the helicity of the W bosons in the top quark rest frame. Ourmeasurement uses a tt sample isolated in 106 +/- 4 pb(-1) of data collected in <p(p)over bar> collisions at root s = 1.8 TeV with the CDF detector at the Fermilab Tevatron. Assuming a standard. V-A weak decay, we find that the fraction of W's with zero helicity in the top rest frame is F-0 = 0.91 +/- 0.37(stat) +/- 0.13(syst), consistent with the standard model prediction of F-0 = 0.70 for a top mass of 175 GeV/c(2).

Measurement of the helicity of W bosons in top quark decays

BISELLO, DARIO;BUSETTO, GIOVANNI;DORIGO, TOMMASO;LORETI, MAURIZIO;MARIOTTI, MOSE';BIGONGIARI, CIRO;SCODELLARO, LUCA
2000

Abstract

We use the transverse momentum spectrum of leptons in the decay chain t --> bW with W --> l nu to measure the helicity of the W bosons in the top quark rest frame. Ourmeasurement uses a tt sample isolated in 106 +/- 4 pb(-1) of data collected in collisions at root s = 1.8 TeV with the CDF detector at the Fermilab Tevatron. Assuming a standard. V-A weak decay, we find that the fraction of W's with zero helicity in the top rest frame is F-0 = 0.91 +/- 0.37(stat) +/- 0.13(syst), consistent with the standard model prediction of F-0 = 0.70 for a top mass of 175 GeV/c(2).
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11577/1335984
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