Related papers: The Mass Effect in Quarkonium Decay
Quarkonium decays are studied in the charmonium model. Relativistic corrections, higher-order perturbative QCD corrections and non- perturbative contributions are discussed. Recent measurements of charmonium annihilation rates are used to…
The partial decay rate $\Gamma(Z\to b\bar{b})$ is significantly influenced by the mass of the top quark due to electroweak radiative corrections. The leading $\sim m_t^2$ and the next-to-leading contribution $\sim \ln m_t^2$ are known to be…
Next-to-leading order QCD corrections to the $\gamma^{*} \longrightarrow Q\bar{Q}-Reggeon$ vertex are calculated, where $Q\bar{Q}$ denotes a heavy quark pair $c\bar c$ or $b\bar b$. The heavy quark mass effects on the photon impact factor…
We study the impact on the primordial abundances of light elements created by a variation of the quark masses at the time of Big Bang nucleosynthesis (BBN). In order to navigate through the particle and nuclear physics required to connect…
The influence of tensor forces on hyperfine splitting and decay widths of mesons are investigated within the limits of quasirelativistic potential quark model. As the starting the system of the Rarita-Schwinger equations is used. We use a…
I review the cancellation of non-perturbative 1/m_Q corrections to the heavy quark inclusive decay width. I summarize the results of an explicit second loop order calculation in perturbation theory which shows the absence of linear…
For three-body hadron decays mediated by intermediate resonances with large widths, we show how to properly extract the quasi-two-body decay rates for a meaningful comparison with the corresponding theoretical estimates, using several $B$…
We estimate the decay rates of $\eta_c\rightarrow 2\gamma$, $\eta_c'\rightarrow 2\gamma$, and $J/\psi\rightarrow e^+ e^-$, $\psi^\prime\rightarrow e^+e^-$, by taking into account both relativistic and QCD radiative corrections. The decay…
It is well known that in perturbation theory existence of quasi-degenerate states can rearrange the order counting. For a heavy quarkonium system, naively, enhanced effects ($l$-changing mixing effects) could contribute already to the…
We study relativistic corrections in exclusive $S$-wave charmonium decays into proton-antiproton final state. We calculate the NRQCD corrections to the dominant decay amplitude, which depend on the nucleon twist-3 light-cone distribution…
We derive the imaginary part of the potential NRQCD Hamiltonian up to order 1/m^4, when the typical momentum transfer between the heavy quarks is of the order of Lambda_{QCD} or greater, and the binding energy E much smaller than…
The most recent lattice results on the QCD phase diagram in the presence of a strong magnetic field strongly disagree with results from previous lattice simulations and several model calculations. The most remarkable difference is the…
A model for the production of quarkonium states in the midrapidity region at RHIC and LHC energy range is presented which explores well understood properties of QCD only. An increase of the quarkonium hadronisation time with the initial…
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…
We consider the effects of quark masses to the perturbative thrust in $e^+e^-$ annihilation. In particular we show that perturbative power corrections resulting from non-zero quark masses considerably alters the size of the non-perturbative…
This study examines the properties of heavy quarkonia $X$ by treating them as bound states of $Q$ and $\bar{Q}$ at the LO level within the NRQCD framework, where $Q$ represents either a charm or a bottom quark. The branching ratios for the…
Recent results on the QCD analysis of bound states of heavy $\bar{q}q$ quarks are reviewed, paying attention to what can be derived from the theory with a reasonable degree of rigour. We report a calculation of $\bar{b}c$ bound states; a…
Recently, a new perturbative QCD factorization formalism for heavy quarkonium production at a large transverse momentum was proposed. Phenomenological application of this new approach relies on our knowledge of a large number of universal…
Hadronic annihilation rate of $1^{+-}$ heavy quarkonium is given to next-to-leading order in $\alpha_s$ and leading order in $v^2$ using a recently developed factorization formalism which is based on NRQCD. The result includes both the…
Lattice NRQCD has proven successful in describing the physics of the upsilon system and B-mesons, though some concerns arise when it is used in simulations of charm quarks. It is certainly possible that the NRQCD expansion is not converging…