arXiv subjects

Zoltán Trócsányi

Publications and source records attributed to Zoltán Trócsányi.

40 records · Page 3Linked to original sources

arXiv1996

Calculation of QCD jet cross sections at next-to-leading order

A general method for calculating \NLO cross sections in perturbative QCD is presented. The algorithm is worked out for calculating $N$-jet cross sections in hadron-hadron collisions. The generalization of the scheme to performing caclulations for other QCD process, such as electron-positron annihilation or in deep inelastic scattering is also straightforward. As an illustration several three-jet cross section distributions in electron-positron annihilation, calculated using the algorithm, are presented.

hep-ph↗

arXiv1996

Three-jet cross section in hadron collisions at next-to-leading order: pure gluon processes

The next-to-leading order three-jet cross section in hadron collisions is calculated in the simplified case when the matrix elements of all QCD subprocesses are approximated by the pure gluon matrix element. The longitudinally-invariant $k_\perp$ jet-clustering algorithm is used. The important property of reduced renormalization and factorization scale dependence of the next-to-leading order physical cross section as compared to the Born cross section is demonstrated.

hep-ph↗

arXiv1993

One-loop helicity amplitudes for all 2 -> 2 processes in QCD and N=1 supersymmetric Yang-Mills theory

One loop corrections to the helicity amplitudes of all 2 -> 2 subprocesses are calculated in QCD and in N=1 supersymmetric Yang-Mills theory using two versions of dimensional regularization: the `t~Hooft-Veltman scheme and dimensional reduction. Studying the structure of the soft and collinear singularities, we found universal transition rules for the squared matrix element which can be used to translate the results obtained in these schemes to the results valid in the conventional dimensional regularization scheme. With explicit calculation it is demonstrated that the one loop helicity amplitudes of the 2 -> 2 subprocesses calculated using dimensional reduction in the N=1 supersymmetric $SU(N)$ gauge theory respect the supersymmetry Ward identities. Our transition rules can also be used to calculate the next-to-leading order Altarelli-Parisi kernels in the dimensional reduction scheme when they satisfy supersymmetry Ward identities as well.

hep-ph↗

arXiv1992

QCD Corrections to Photon Production in Association with Hadrons in $e^+e^-$ Annihilation

A detailed investigation of the theoretical ambiguities present in the QCD description of photon production in $e^+e^-$ annihilation is given. It is pointed out that in a well-defined perturbative analysis it is necessary to subtract the quark-photon collinear singularities. This subtraction requires the introduction of an unphysical parameter in the perturbative part of the cross section. The subtracted term is factored into non-perturbative fragmentation function. The dependence on the unphysical parameter cancels in the sum of non-perturbative and perturbative parts. It is pointed out that for $E_γ\le \sqrt{s}/(2(1+ε_c))$ the non-perturbative contributions are suppressed. Using a general purpose next-to-leading order Monte Carlo program, we calculate various physical quantities that were measured in LEP experiments recently.

hep-ph↗