Related papers: Quartic Mass Corrections to $R_{had}$
We compute next-to-leading order QCD corrections to the process $gg\to ZH$. In the effective-theory approach we confirm the results in the literature. We consider top quark mass corrections via an asymptotic expansion and show that there is…
We calculate the second-order QCD corrections to the forward-backward asymmetry in $e^+e^-$ annihilation. Using the quark axis definition, we do not agree with either existing calculation, but the difference relative to one of them is small…
We present the three-loop QCD corrections to the quark chromomagnetic moment including two different nonzero masses. This is a necessary ingredient to obtain the corresponding corrections to the chromomagnetic coefficient in the Heavy Quark…
The total cross section for electron-positron annihilation into hadrons is calculated in the region just below the B meson threshold. QCD corrections up to third order, quark mass effects, initial state radiation, the running of alpha_QED…
Theory results on precision measurements in electron-positron annihilation at low and high energies are collected. These cover pure QCD calculations as well as mixed electroweak and QCD results, involving light and heavy quarks. The impact…
We present results for several thermodynamic quantities within the next-to-leading order calculation of the thermodynamic potential in perturbative QCD at finite temperature and chemical potential including non-vanishing quark masses. These…
A nonrelativistic decomposition for the quark energy by the ratio of the dispersion of quark momentum squared and the effective quark mass is investigated in the framework of the relativistic oscillator constituent quark model as bound…
Effects associated with hyperfine mass splitting between pseudo\-scalar and vector mesons may induce surprisingly large $1/{m}_{Q}^{2}$ corrections in the heavy quark expansion. We demonstrate this in a relativistic quark model by…
We calculate the leading quark mass corrections of order $m_q\log(m_q)$, $m_q$ and $m_q^{3/2}$ to the vector meson decay constants within Heavy Vector Meson Chiral Perturbation Theory. We discuss the issue of electromagnetic gauge…
Joint energy distribution of the bottom quark and antiquark from decays of the top quark and antiquark produced in the reaction $e^+ e^- \to t \bar{t}$ is studied. Main emphasis is put on $CP$-violation effects in the interaction of the…
We present the first results of next-to-leading order QCD corrections to three jet heavy quark production at LEP including mass effects. Among other applications, this calculation can be used to extract the bottom quark mass from LEP data,…
We probe effects of the partial chiral symmetry restoration to the mass of heavy-light mesons in a constituent quark model by changing the constituent quark mass of the light quark. Due to the competing effect between the quark mass and the…
In the framework based on the quasipotential method and relativistic quark model a new covariant expression for the heavy quark fragmentation amplitude to fragment into the pseudoscalar and vector S-wave heavy mesons is obtained. It…
Relativistic covariance requires that in the constituent quark model for mesons the positive energy states as well as the negative energy states are included. Using relativistic quasi-potential equations the contribution of the negative…
The calculation of the quartic mass terms at order \alpha_s^3 to the hadronic R ratio is described. It is based on the operator product expansion for the quark current correlator, combined with an application of the renormalization group…
We study the shift in the $\Upsilon$ mass due to a non-zero charm quark mass. This shift affects the value of the $\bar{\rm MS}$ $b$-quark mass extracted from the $\Upsilon$ system by about -20 MeV, due to an incomplete cancellation of…
Quantum chromodynamics (QCD) effects in the semileptonic decay b -> c l nu are evaluated to the second order in the coupling constant, O(alpha_s^2), and to several orders in the expansion in quark masses, m_c/m_b. Corrections are calculated…
The mass spectra and electromagnetic decay rates of charmonium, bottomonium and B_c mesons are comprehensively investigated in the relativistic quark model. The presence of only heavy quarks allows the expansion in powers of their…
We compute two-loop corrections to the vector current matching coefficient involving two heavy quark masses. The result is applied to the computation of the $\Upsilon(1S)$ decay width into an electron or muon pair. We complement the…
The dispersive analysis of the decay $\eta\to3\pi$ is reviewed and thoroughly updated with the aim of determining the quark mass ratio ~$Q^2=(m_s^2-m_{ud}^2)/(m_d^2-m_u^2)$. With the number of subtractions we are using, the effects…