相关论文: Fully automated calculation in fermion scattering
In this paper, analytical formulas for elastic neutrino-fermion scattering cross sections are presented. These are evaluated in the limit where the neutrino mass is neglible compared to the incoming momentum. The fermion mass is taken into…
We describe the program package gentle/4fan, which consists of the Fortran codes gentle\_4fan.f, 4fan.f, and gentle\_nc\_qed.f and is devoted to the description of e+ e- annihilation into four fermions. The codes are based on the…
The $O(\alpha)$ corrections to $\gamma\gamma --> f \bar f$ in the Standard Model are calculated for arbitrary, light fermions $f$. The relevant analytical results are listed in a form that is appropriate for practical applications, and…
The proposed Electron-Ion Collider (EIC) will utilize high-luminosity high-energy electron+proton ($e+p$) and electron+nucleus ($e+A$) collisions to solve several fundamental questions including searching for gluon saturation and studying…
Three programs are presented for automatically generating and calculating Feynman diagrams: the diagrams are generated with FeynArts, algebraically simplified with FormCalc, and finally evaluated numerically using the LoopTools package. The…
This paper presents the high-precision theoretical predictions for $e^+e^- \to l^-l^+$ scattering. Calculations are performed using the {\tt SANC} system. They take into account complete one-loop electroweak radiative corrections as well as…
We introduce a new method to treat Majorana fermions and interactions with fermion-number violation on the GRACE system which has been developed for the automatic computation of the matrix elements for the processes of the standard model.…
We use a recent O(alpha_s^2) calculation of the differential cross section for the production of heavy quarks in e+e- annihilation to compute a few moments of the heavy quark single-inclusive production cross section. We verify that,…
In this paper we describe the implementation of the QED process $\gamma\gamma\to\gamma\gamma$ through a fermion loop into the framework of SANC system. The computations of this process takes into account non-zero mass of loop-fermion. We…
Results from studies on exclusive production of electron-position pair, di-photon, and di-jet production at CDF in proton-antiproton collisions at the Fermilab Tevatron are presented. The first observation and cross section measurements of…
We apply the recently proposed amplitude reduction at the integrand level method, to the computation of the scattering process 2 photons -> 4 photons, including the case of a massive fermion loop. We also present several improvements of the…
We derive compact analytical formulae of the Bonneau-Martin type for the reaction e+e- to bar-f f gamma with cuts on minimal energy and acollinearity of the fermions, where the photons may be emitted both from the initial or final states.…
This note describes two versatile accelerator complexes that could be built at a Future Circular Collider (FCC) in order to produce $e^{+}e^{-}$, $\gamma\gamma$ and $ep$ collisions. The first facility is an SLC-type machine comprising a…
In this paper we suggest an {\it iterative} algorithm to compute automatically the scattering matrix elements of any given effective lagrangian, $\Gamma$. By exploiting the relation between $\Gamma$ and the connected Green function…
This paper studies the electroweak production of all possible four fermion states in e+ e- collisions. Since the methods employed to evaluate the complete matrix elements and phase space are very general, all four fermion final states in…
The most interesting Higgs-production processes at future e+ e- colliders belong to the process class e+ e- -> f anti-f H. We study the full O(alpha) corrections to this reaction in the Standard Model for neutrinos and top quarks in the…
We study Standard Model four-fermion production in e+ e- annihilation at LEP2 energies and above using a semi-analytical approach. We derive the complete QED initial state corrections (ISR) to the reactions e+e- -> ZZ ->…
We report on automating the Catani-Seymour dipole subtraction which is a general procedure to treat infrared divergences in real emission processes at next-to-leading order in QCD. The automatization rests on three essential steps: the…
A new version of CARLOMAT that allows to generate automatically the Monte Carlo programs dedicated to the description of the processes e+e- -> hadrons at low center-of-mass energies is presented. The program has been substantially modified…
Complete Feynman diagram automatic computation systems are now coming of age after many years of development. They are made available to the high energy physics community through user-friendly interfaces. Theorists and experimentalists can…