A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the subtraction terms I

In previous articles we outlined a subtraction scheme for regularizing doubly-real emission and real-virtual emission in next-to-next-to-leading order (NNLO) calculations of jet cross sections in electron-positron annihilation. In order to find the NNLO correction these subtraction terms have to be integrated over the factorized unresolved phase space and combined with the two-loop corrections. In this paper we perform the integration of all one-parton unresolved subtraction terms

A subtraction scheme for computing QCD jet cross sections at NNLO: regularization of real-virtual emission

We present a subtraction scheme for computing jet cross sections in electron-positron annihilation at next-to-next-to-leading order accuracy in perturbative QCD. In this second part we deal with the regularization of the real-virtual contribution to the NNLO correction.Comment: 32 pages, LaTeX file, uses pstrick

Energy-energy correlation in electron-positron annihilation at NNLL+NNLO accuracy

We present the computation of energy-energy correlation in $e^+e^-$ collisions in the back-to-back region at next-to-next-to-leading logarithmic accuracy matched with the next-to-next-to-leading order perturbative prediction. We study the effect of the fixed higher order corrections in a comparison of our results to LEP and SLC data. The next-to-next-to-leading order correction has a sizable impact on the extracted value of $\alpha_{\mathrm S}(M_Z)$, hence its inclusion is mandatory for a precise measurement of the strong coupling using energy-energy correlation.Comment: 24 pages, 7 figures and 1 table, published versio

Jet production in the CoLoRFulNNLO method: event shapes in electron-positron collisions

We present the CoLoRFulNNLO method to compute higher order radiative corrections to jet cross sections in perturbative QCD. We apply our method to the computation of event shape observables in electron-positron collisions at NNLO accuracy and validate our code by comparing our predictions to previous results in the literature. We also calculate for the first time jet cone energy fraction at NNLO.Comment: 45 pages and 6 figures, note adde

Nagy pontosságú Monte Carlo programok nagyenergiás részecskeütközések leírására = Precision Monte Carlo tools for collider experiments

Nem pontosan a terveknek megfelelően, mégis nemzetközileg elismert eredményeket értünk el a QCD két területén: a sugárzási korrekciók számításában és a Monte Carlo partonzápor programokban. Sugárzási korrekciók számítása Teljesen numerikus eljárást dolgoztunk ki egyhurok QCD amplitúdók számolására, és elsőként számítottuk ki az N-foton (N = 4,6,8) amplitúdókat. Fél-automatikus eljárást fejlesztettünk ki parton szintű súlyozatlan események generálásához, amelyekre közvetlenül lehet partonzápor programot alkalmazni. Ezzel a módszerrel a t tbar és a t tbar + jet keletkezésnek hadron szintű hatáskeresztmetszeteit számítottuk ki, amelyek az első sugárzási korrekciókat pontosan visszaadják az erős csatolás szerinti sorfejtésben. Kifejlesztettük a második QCD sugárzási korrekciók számításának általános elméletét. Duplán feloldatlan tagok kivételével az összes levonási tagot integráltuk a feloldatlan partonok faktorizált fázisterén. Monte Carlo partonzápor programok Rekurziós egyenleteket írtunk fel, amelyek segítségével vezető rendű partonzáport lehet generálni hadronütközésekben. Az eljárás újszerűsége abban áll, hogy figyelembe veszi a különböző amplitúdók közötti interferencia tagokat akkor, amikor azoknak vezető rendű lágy, vagy kollineáris szingularitása van. Figyelembe veszi az elsődleges kölcsönhatásban keletkező partonok szín és spin korrelációit is. | Although not precisely as planned, we made internationally recognized progress in two main areas of QCD: exact higher order computations and Shower Monte Carlo programs. Exact higher order computations We developed a completely numerical approach to computing one-loop QCD amplitudes and for the first time we computed N-photon (N=4,6,8) amplitudes numerically. We devised a semi-automatic approach to generate unweighted Monte Carlo events at the parton level that can be interfaced with shower programs. Using this method, we produced predictions for the hadron level cross section of t tbar and t tbar + jet hadroproduction which are correct up to next-to- leading order accuracy upon expansion in the strong coupling. We presented a general subtraction scheme for computing QCD jet cross sections at next-to-next-to-leading order accuracy. We integrated the subtraction terms over the factorised phase space of the unresolved partons except the doubly-unresolved subtractions. Shower Monte Carlo programs We specified recursive equations that can be used to generate a lowest order parton shower for hard scattering in hadron-hadron collisions. The novelty of the approach is that it incorporates quantum interference between different amplitudes in those cases in which the interference diagrams have leading soft or collinear singularities. It also incorporates the color and spin information carried by partons emerging from a hard interaction

TRADITION, QUALITY AND BIOTECHNOLOGY IN HUNGARIAN SPICE PEPPER (Capsicum annuum L.) BREEDING

Spice pepper production has a history of almost 300 years in the southern part of Hungary. In this study the results of two biotechnological improvements are summarized. Anther and isolated microspore culture techniques were improved to release haploid and doubled haploid (DH) lines for spice pepper breeding. Both the anther and isolated microspore culture methods were successfully used in spice pepper haploid production. Microspore culture- derived structures were analysed to identify their different parts. Green plantlets were regenerated from embryos derived from both anther and microspore cultures. Their doubled haploid analogues were integrated into Hungarian spice pepper hybrid seed breeding programmes. One hybrid, Sláger, was released as a new genotype for spice pepper production in 2008 and two hybrid candidates (Délibáb and Bolero) are now being tested in official trials

Applying Activity-based Costing at Logistics Service Providers

Logistics service providers run business under a considerable pressure. They have to provide high quality logistics services at lowest possible prices and at the same time have to ensure a sustainable, profitable operation. This kind of business management requires reliable and true information about service costs. Distortions of costing information shall be minimised and the drivers of costs shall be accurately explored. Activity-based costing with methodological and industry specific adaptations may be used to improve the accuracy of logistics service providers’ costing procedures. Additionally, it can deliver information on cost efficiency as well. Thus this paper aims to analyse the applicability of activity-based costing for the case of logistics service providers. A specialised cost calculation model is elaborated and tested under real-world circumstances. The functionality of the model is illustrated by pilot calculations. This shows that significant differences might exist between the results of activity-based costing and the outcomes of traditional costing. The significance of differences is in line with the complexity and heterogeneity of logistics services

Three-jet production in electron-positron collisions using the CoLoRFulNNLO method

We introduce a subtraction method for jet cross sections at next-to-next-to-leading order (NNLO) accuracy in the strong coupling and use it to compute event shapes in three-jet production in electron-positron collisions. We validate our method on two event shapes, thrust and C-parameter, which are already known in the literature at NNLO accuracy and compute for the first time oblateness and the energy-energy correlation at the same accuracy.Comment: 5 pages, 6 figure

Subtraction method of computing QCD jet cross sections at NNLO accuracy

We present a general subtraction method for computing radiative corrections to QCD jet cross sections at next-to-next-to-leading order accuracy. The steps needed to set up this subtraction scheme are the same as those used in next-to-leading order computations. However, all steps need non-trivial modifications, which we implement such that that those can be defined at any order in perturbation theory. We give a status report of the implementation of the method to computing jet cross sections in electron-positron annihilation at the next-to-next-to-leading order accuracy.Comment: 6 pages, talk given at the conference "Loops and Legs in Quantum Field Theory", Sondershausen, April 200