Related papers: The negative binomial distribution in quark jets w…
Top-quark pair production in association with two b-jets is computed at next-to-leading order QCD precision, including effects of the b-quark mass, and matched to a $t\bar{t}$+jets simulation in a variable flavor number scheme. The Monte…
In this paper we study the factors of some alternating sums of products of binomial and q-binomial coefficients. We prove that for all positive integers n_1,...,n_m, n_{m+1}=n_1, and 0\leq j\leq m-1, {n_1+n_{m}\brack…
We present predictions of two event shape distributions, the light hemisphere mass and the narrow jet broadening, to next-to-leading logarithmic order. We apply the coherent branching formalism to resum the leading O(alphas^n L^{2n-1}) and…
We compute the primary Lund plane density for jets initiated by a massive ($b$) quark to single logarithmic accuracy in Quantum Chromodynamics (QCD). In order to capture mass effects, we consider quasi-collinear factorisation and we include…
We examine hadron multiplicity fluctuations in hard processes and confront analytic QCD predictions with the pattern of multiplicity fluctuations observed in $e^+e^-$ annihilation and high-$p_t$ jets produced in $pp$ collisions at the LHC.…
We discuss the renormalization and factorization scale dependence of charm and bottom production both at fixed-target energies and at present and future colliders. We investigate whether distributions calculable at leading order can be…
We have studied the determination of the running b-quark mass, $m_b(M_Z)$, using $Z^0$ decays into 3 or more hadronic jets. We calculated the ratio of $\geq3$-jet fractions in $e^+e^-\to b\bar{b}$ vs. $e^+e^-\to q_l\bar{q_l}$ ($q_l$ = u or…
For very heavy quarks, the two heavy quarks in a doubly heavy baryon are expected to form a pointlike, heavy diquark in an antitriplet color configuration. In this limit the dynamics of the light degrees of freedom `factorize' from the…
We review the current status of analyses of multijet final states in e+e- annihilation. Results for jet observables from LEP 1, LEP 2 and from the reanalysis of the PETRA experiment JADE will be presented. A determination of the b-quark…
We consider the hadronic B decays B0bar -> D0 eta, B0bar -> D*0 eta, B0bar -> D0 eta', B0bar -> D*0 eta' in the framework of a quark-flavour basis and factorization. The formalism allows to compute the decays to the eta meson and to relate…
Conditions for positive and polynomial recurrence have been proposed for a class of reliability models of two elements with transitions from working state to failure and back. As a consequence, uniqueness of stationary distribution of the…
We present factorization theorems for two exclusive heavy-quarkonium production processes: production of two quarkonia in e^+e^- annihilation and production of a quarkonium and a light meson in B-meson decays. We describe the general proofs…
We study divisibility properties of certain sums and alternating sums involving binomial coefficients and powers of integers. For example, we prove that for all positive integers $n_1,..., n_m$, $n_{m+1}=n_1$, and any nonnegative integer…
The angular correlations of four-jet events from hadronic decays of the Z0 have been studied in the past mainly to extract from them the fundamental constants of quantum chromodynamics called colour factors. Previous studies have used all…
A multidimensional study of local multiplicity fluctuations and multiparticle correlations of hadrons produced in Z decays is performed. The study is based on the data sample of more than 4 million events recorded with the OPAL detector at…
Quantum chromodymamics (QCD) approach to the problem of multiplicity distributions in high energy particle collisions is described. The solutions of QCD equations for generating functions of the multiplicity distributions in gluon and quark…
We consider the computation of D and B fragmentation functions in e+e- annihilation. We compare the results of fitting present data using the next-to-leading-logarithmic resummed approach, versus the O(alpha_s^2) fixed-order calculation,…
We review the production of charm and bottom quarks in two-photon collisions at e+e- colliders. The next-to-leading order QCD predictions for total cross sections and differential distributions are compared with recent experimental results.
We develop the event-by-event picture of the gluon distribution produced via medium-induced gluon branching by an energetic jet which propagates through a dense QCD medium. A typical event is characterized by the production of a large…
Processes involving heavy quarks in associated production, are usually described in two factorisation schemes: one in which the heavy quark is treated as an infinitely massive object, decoupled from QCD evolution, and one in which it is…