We use the transverse momentum spectrum of leptons in the decay chain t→bW with W→lv to measure the helicity of the W bosons in the top quark rest frame. Our measurement uses a tt̄ sample isolated in 106±4pb-1 of data collected in pp̄ collisions at √s=1.8TeV 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 F0=0.91±0.37(stat)±0.13(syst), consistent with the standard model prediction of F0=0.70 for a top mass of 175GeV/c2.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)