arXiv subjects

Marek Jezabek

Publications and source records attributed to Marek Jezabek.

6 recordsLinked to original sources

arXiv1997

Tau lepton distributions in semileptonic B decays

Analytic formulae are given for order alpha_s perturbative QCD corrections to the double differential distribution of the tau lepton energy and the invariant mass of the tau + antineutrino system in semileptonic decays of the bottom quark. The corresponding distribution for B meson decays are obtained by combining these results and the nonperturbative QCD corrections calculated by Falk et al. The moments of the energy distribution of the tau lepton are calculated.

hep-ph↗

arXiv1996

Perturbative QCD corrections to inclusive lepton distributions from semileptonic $b \to cτ\barν_τ$ decays

Perturbative corrections of the order of $α_s$ to inclusive double differential lepton distribution from $b$ quark decay are considered. A perturbative correction to the charged lepton energy spectrum has been calculated for an arbitrary charged lepton mass. The perturbative contribution suppresses the partial rate but almost does not change the shape of energy distribution. Applications of our result to semileptonic B meson decays are briefly discussed.

hep-ph↗

arXiv1995

Top Quark Pair Production in the Threshold Region

Recent results on production and decays of polarized top quarks are reviewed. Top quark pair production in $e^+e^-$ annihilation is considered near energy threshold. For longitudinally polarized electrons the produced top quarks and antiquarks are highly polarized. Dynamical effects originating from strong interactions and Higgs boson exchange in the $t-\bar t$ system can be calculated using the Green function method. Energy-angular distributions of leptons in semileptonic decays are sensitive to the polarization of the decaying top quark and to the Lorentz structure of the weak charged current.

hep-ph↗

arXiv1995

Recent Results on QCD Corrections to Semileptonic $b$-Decays

We summarize recent results on QCD corrections to various observables in semileptonic $b$ quark decays. For massless leptons in the final state we present effects of such corrections on triple differential distribution of leptons which are important in studies of polarized $b$ quark decays. Analogous formulas for distributions of neutrinos are applicable in decays of polarized $c$ quarks. In the case of decays with a $τ$ lepton in the final state mass effect of $τ$ has to be included. In this case we concentrate on corrections to the total decay width.

hep-ph↗

arXiv1994

Radiative corrections to $b\to cτ\batν_τ$

Analytical calculation is presented of the QCD radiative corrections to the rate of the process $b\to cτ\barν_τ$ and to the $τ$ lepton longitudinal polarization in $τ\barν_τ$ rest frame. The results are given in the form of one dimensional infrared finite integrals over the invariant mass of the leptons. We argue that this form may be optimal for phenomelogical applications due to a possible breakdown of semilocal hadron-parton duality in decays of heavy flavours.

hep-ph↗

arXiv1994

QCD Corrections to Inclusive Distributions of Leptons in Decays of Polarised Heavy Quarks

Compact analytic expressions have been obtained for the first order perturbative QCD corrections to the inclusive spectra of the leptons in the semileptonic decays of polarised heavy quarks. Charmed and beautiful $Λ$ baryons from $Z^0$ decays can be viewed as sources of highly polarised charm and bottom quarks. Charged leptons and neutrinos from $Λ_b$ and $Λ_c$ decays can be used in the polarisation studies for the corresponding heavy quarks. Thus our results are applicable for the b quark polarisation measurements at LEP. Short lifetime enables polarisation studies for the top quark. The angular-energy spectra of the charged leptons are particularly useful in this respect whereas the distributions of the neutrinos are sensitive to deviations from the V-A structure of the charged weak current in the decay.

hep-ph↗