 Home

Codex Wiki

List of universities

University of Oxford

Course of the University of Oxford

Undergraduate course of the University of Oxford

Physics course of the University of Oxford

Year 4 of the physics course of the University of Oxford

Particle physics course of the University of Oxford

Past exam of the particle physics course of the University of Oxford

2017

Top decay occurs before a <Hadronization>[colour-bound] hadron can form. Using representative scales $\Gamma_t\sim1$–$1.5\,\mathrm{GeV}$ and $\Lambda_{\mathrm{QCD}}\sim0.2\,\mathrm{GeV}$,
$$
\boxed{\tau_t\sim\frac\hbar{\Gamma_t}\sim5\times10^{-25}\,\mathrm s
<\tau_{\mathrm{had}}\sim\frac\hbar{\Lambda_{\mathrm{QCD}}}\sim3\times10^{-24}\,\mathrm s.}
$$
Thus <top quarks> do not live long enough to form ordinary top-containing mesons. The decay products still participate in <QCD> radiation and <hadronization>, so “free decay” here means decay before binding, not a stable observable free <Color charge>[coloured] asymptotic particle.

Solution

Past exam of the particle physics course of the University of Oxford / 2017 / 6 / b / Solution

Past exam of the particle physics course of the University of Oxford / 2017 / 6 / b / Solution

 Ancestors (12)

 Discussion (0)

 Articles by others on the same topic (0)

Past exam of the particle physics course of the University of Oxford / 2017 / 6 / b / Solution

 Ancestors (12)

 Discussion (0)  Subscribe (1)

 Articles by others on the same topic (0)

 Discussion (0)