相关论文: Resummed $C$-Parameter Distribution in $e^+e^-$ An…
We discuss the issue of interplay between perturbative and non-perturbative phenomena for power corrections to e+e- event shapes.
We study the large-order asymptotic behavior of the perturbation series for short-distance coefficients in the NRQCD factorization formulas for the decays J/psi --> e^+e^- and eta_c --> gamma gamma. The short-distance coefficients of the…
The resummation for the event-shape variable jet broadening is extended to next-to-next-to-leading logarithmic accuracy by computing the relevant jet and soft functions at one-loop order and the collinear anomaly to two-loop accuracy. The…
I review a few selected topics concerning heavy-quark fragmentation, taking particular care about bottom- and charm-quark production in $e^+e^-$ annihilation and the inclusion of non-perturbative corrections. In particular, I discuss recent…
A new statistical model for multiparticle production in $e^+e^-$ annihilation is proposed based on the idea of the longitudinal phase space with limited transverse momentum. The longitudinal rapidity space is divided into cells of equal…
We study the annihilation process $p\bar{p} \to \pi^0 e^+ e^-$ within a Regge framework, as a means to provide constraints on timelike nucleon form factors. We present results for the $e^+e^-$ angular distributions and the differential…
The `renormalon' or `dispersive' method for estimating non-perturbative corrections to QCD observables is reviewed. The corrections are power-suppressed, i.e. of the form $A/Q^p$ where $Q$ is the hard process momentum scale. The renormalon…
The reversible reactions A+A<=>C and A+B<=>C are investigated. From the exact Langevin equations describing our model, we set up a systematic approximation scheme to compute the approach of the density of C particles to its equilibrium…
A method for the resummation of nonalternating divergent perturbation series is described. The procedure constitutes a generalization of the Borel-Pad\'{e} method. Of crucial importance is a special integration contour in the complex plane.…
Charged particle momentum distributions are studied in the reaction e+e- -> hadrons, using data collected with the OPAL detector at centre-of-mass energies from 192 GeV to 209 GeV. The data correspond to an average centre-of- mass energy of…
The Modified Leading Log Approximation of QCD and the local parton hadron duality picture are shown to give a fully satisfactory description of data on charged particle energy spectra in $e^+e^-$ annihilation. The analysis of data in terms…
We consider large-angle two photon production in $e^+ e^-$ annihilation as a possible process to monitor the luminosity of a future $e^+ e^-$ circular collider (FCC-ee). We review and assess the status of the theoretical accuracy by…
The distributions of the bottom quark in the process $e^+ e^- \to t \, \bar{t} \to b \, W^+ \, \bar{t}$ are considered at the $e^+ e^-$ energy corresponding to the first construction stage of the Compact Linear Collider. The cross sections…
We introduce the azimuthal correlation for the deep inelastic scattering process. We present the QCD prediction to the level of next-to-leading log resummation, matching to the fixed order prediction. We also estimate the leading…
We present a QCD analysis of the cumulative out-of-event-plane momentum distribution in DIS process with emission of high p_t jets. We derive the all-order resummed result to next-to-leading accuracy and estimate the leading power…
We have measured the distributions of the jet energies in e+e- --> qq^bar g events, and of the three orientation angles of the event plane, using hadronic $Z^0$ decays collected in the SLD experiment at SLAC. We find that the data are well…
We have applied so-called `optimised' perturbation theory to resolve the renormalisation-scale (mu) ambiguity of exact O(alpha_s^2) QCD calculations of event shape observables in e+e- --> hadrons. We fitted the optimised predictions for 15…
We study the radiative processes that affect the propagation of a high energy gluon in a dense medium, such as a quark-gluon plasma. In particular, we investigate the role of the large double logarithms corrections, $\sim\alpha_s \ln^2…
We calculate the form factor and cross section of the excited charmonium production process $e^{+}+e^{-}\rightarrow \psi \left ( 2S \right )+\eta _{c}$ by light-cone sum rules. In our method, the form factor depends on the distribution…
For many event-shape observables, the most difficult part of a resummation in the Born limit is the analytical treatment of the observable's dependence on multiple emissions, which is required at single logarithmic accuracy. We present a…