Related papers: Resummed $C$-Parameter Distribution in $e^+e^-$ An…
The current status of theoretical work and experimental analyses on power corrections in QCD for e+e- annihilation will be reviewed. Measurements of the number of active quark flavours n_f and the QCD colour factors C_A and C_F derived from…
We have studied hadronic events from e+e- annihilation data at centre-of-mass energies of sqrt{s}=172, 183 and 189 GeV. The total integrated luminosity of the three samples, measured with the OPAL detector, corresponds to 250 pb^-1. We…
The collimation $C$ of a hadronic event in the e^+e^- annihilation is defined as the average of $\cos\theta$, $C=<\cos\theta>$, where $\theta$ is the angle of each hadron measured from the thrust axis, and the average is over all the…
We review the orientation of e+e- \to q\bar q g events in terms of the polar and azimuthal angles of the event plane w.r.t. the electron beam direction. The asymmetry of the azimuthal-angle distribution is, like the left-right…
In cross sections with angular cuts, an intricate pattern of enhanced higher-order corrections known as non-global logarithms arises. The leading logarithmic terms were computed numerically two decades ago, but the resummation of subleading…
We present a calculation of non-global logs at finite $\mathrm{N_c}$ for the hemisphere mass distribution in $e^+e^-\to 2$ jets at single log accuracy up to fifth order in the strong coupling constant. Our results suggest a possible…
We compute the fixed-order distribution of the non-global hemisphere mass observable in $e^+ e^-$ annihilation up to four loops for various sequential recombination jet algorithms. In particular, we focus on the $k_t$ and Cambridge/Aachen…
We present a complete calculation of the photon +~1 jet rate in $e^+e^-$ annihilation up to ${\cal O}(\alpha \alpha_{s})$. Although formally of next-to-leading order in perturbation theory, this calculation contains several ingredients…
In this paper, we calculate the resummed jet mass distribution up to next-to-leading logarithmic accuracy for jets defined with the trimming groomer in Z+jet events at the LHC. We compute at fixed order and to all orders the large…
We propose four simple event-shape variables for semi-inclusive $e^+e^- \to 4$-jet events. The observables and cuts are designed to be especially sensitive to subleading aspects of the event structure, and allow to test the reliability of…
We present the next-to-leading order (O(alpha_s^3)) perturbative QCD predictions for e^+e^- annihilation into four jets. A previous calculation omitted the O(alpha_s^3) terms suppressed by one or more powers of 1/N_c^2, where N_c is the…
We examine non-global and clustering logarithms in the distribution of the azimuthal decorrelation between two jets in $e^+e^-\to$ dijet events, where the jets are defined with $E$-scheme recombination in the generalized $k_t$ algorithm. We…
In this paper, we give comprehensive analyses for event shape observables in electron-positron annihilation by using the Principle of Maximum Conformality (PMC) which is a rigorous scale-setting method to eliminate the renormalization…
We present the analysis of the 1/Q-suppressed non-perturbative (NP) contribution to the cumulative out-of-event-plane momentum distribution in e+e- annihilation in the near-to-planar three-jet region. It complements our previous study of…
We study $e^+e^-\to J/\psi c\bar{c}$ by measuring the invariant mass distribution recoiling against fully reconstructed $J/\psi$ decays, using 124 fb$^{-1}$ of data collected with a center-of-mass energy of 10.6 GeV with the $BaBar$…
We show that the next-to-leading order perturbative prediction, matched with the next-to-leading logarithmic approximation for predicting both two-, three- and four-jet rates using the Durham jet-clustering algorithm, in the 0.001 < ycut <…
We derive high-precision results for the $e^+e^-$ heavy jet mass (HJM) $d \sigma/d \rho$ and dihemisphere mass (DHM) $d^2\sigma/(d s_1 d s_2)$ distributions, for $s_1\sim s_2$, in the dijet region. New results include: i) the N$^3$LL…
We discuss the orientation of e+e- -> q qbar g events in terms of the polar and azimuthal angles of the event plane w.r.t. the electron beam direction. We define an asymmetry of the azimuthal-angle distribution, which, along with the…
Analyzing the single inclusive annihilation spectrum of charged hadrons in $e^+e^-$ collisions, I confront the hadronization hypothesis of local parton-hadron duality with a systematic resummation of the dependence on the small energy…
We discuss issues related to the resummation of non-global observables in QCD, those that are sensitive to radiation in only a part of phase space. Examples of such observables are certain single-hemisphere event shapes in e+e- and DIS.…