Related papers: Antenna Showers with One-Loop Matrix Elements
We extend the lowest-order matching of tree-level matrix elements with parton showers to give a complete description at the next higher perturbative accuracy in alpha_s at both small and large jet resolutions, which has not been achieved so…
We compute the one-loop QCD amplitudes for the decay of an off-shell vector boson with vector couplings into a quark-antiquark pair accompanied by two gluons keeping, for the first time, all orders in the number of colours. Together with…
We present a detailed technical derivation of matching conditions at next-to-next-to-leading order in the sectorised VINCIA parton shower, by considering leading-colour 2-, 3- and 4-jet rates in hadronic Z-boson decays. In particular, we…
The branching processes in parton showers are studied in perturbative QCD for both quark and gluon jets. The emphasis is on the nature of fluctuations of both the parton multiplicities and the spatial patterns of the final states. Effective…
A modified version of the CKKW matrix element merging algorithm is presented, suitable for use in an angular-ordered parton shower, using truncated showers and forced splittings. The algorithm is implemented in the Herwig++ Monte Carlo…
A new event generator is proposed for two processes e+e- -> nu nu-bar gamma and e+e- -> nu nu-bar gamma gamma where nu includes all the neutrino species. The exact matrix elements of single- and double-photon emission, generated by the…
We present a complete calculation of the matrix elements for the processes $q \bar q, gg \to b W^+ \bar b W^- g$ and $qg \to b W^+ \bar b W^- q$ which are relevant for the study of events with an additional jet in $t \bar t$ production at…
We consider soft gluon evolution in the colour flow basis. We give explicit expressions for the colour structure of the (one-loop) soft anomalous dimension matrix for an arbitrary number of partons, and show how the successive…
Parton shower Monte Carlo event generators in which the shower evolves from hard splittings to soft splittings generally use the leading color (LC) approximation, which is the leading term in an expansion in powers of $1/N_\Lc^2$, where…
We investigate angular and energy distributions of medium-induced gluon emission off a quark-antiquark antenna in the framework of perturbative QCD as an attempt toward understanding, from first principles, jet evolution inside the…
With the use of MARTINI, a model which considers evolving QCD jets against a fluid dynamical background, it is shown that the introduction of formation time to the parton shower after the initial hard scattering is essential for a…
We formulate PanScales parton showers for hadron collisions so as to achieve next-to-leading logarithmic (NLL) accuracy across a broad set of observables. We do so specifically for colour singlet production. Relative to the existing…
Guided by the colour-diagonal structure of collinear singularities, we identify a set of kinematic basis functions that are well suited to the simplification of soft gluon emission amplitudes. In particular, these basis functions, which…
One of the key ideas in describing the multiparticle production at high energies in the perturbative QCD is the angular ordering in successive soft-gluon emission. We analyse the angular distribution of particles in a jet, and investigate…
We introduce a method for the separation of soft and collinear logarithms in QCD parton evolution at $\mathcal{O}(\alpha_s^2)$ and at leading color. Using an implementation of the technique in the Dire parton shower, we analyze the…
Three jet events arising from decays of the $Z^0$ boson, collected by the DELPHI detector at LEP, were used to measure differences in the properties of quark and gluon jet fragmentation. Gluon jets were anti-tagged in $b\bar{b}g$ events, by…
Coherent QCD radiation in the hadroproduction of top quark pairs leads to a forward--backward asymmetry that grows more negative with increasing transverse momentum of the pair. This feature is present in Monte Carlo event generators with…
We analyse the impact of systematic effects due to the scale dependence of QCD corrections in combination with the use of different jet clustering algorithms in the measurement of the $W^\pm$ mass in the fully hadronic decay mode of…
We describe an algorithm for improving subsequent parton shower emissions by full SU(3) color correlations in the framework of a dipole-type shower. As a proof of concept, we present results from the first implementation of such an…
The spectrum of coherent gluon radiation from a quark-anti-quark pair experiencing multiple scatterings within a coloured medium is central for understanding in-medium parton cascades. Despite its foundational importance, current results…