相关论文: Radiative Corrections to the Photon + 1 Jet Rate a…
We present the results of the calculation of the `photon' +~1 jet rate at ${\cal O}(\alpha \alpha_{s})$ for LEP energies. By comparing these results with the data from the ALEPH Collaboration we make a next-to-leading order determination of…
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…
The production of final state photons in hadronic $Z$-boson decays can be used to study the quark-to-photon fragmentation function $D_{q\to \gamma}(z,\mu_{F})$. Currently, two different observables are used at LEP to probe this function:…
We present a detailed study of photon production in hadronic events in electron-positron annihilation at LEP energies. We show that estimates of the inclusive photon spectrum using the quark-to-photon fragmentation function determined using…
We calculate the rate for $e^+e^-$ annihilation into four jets at next-to-leading order in perturbative QCD, but omitting terms that are suppressed by one or more powers of $1/\Nc^2$, where $\Nc$ is the number of colors. The…
We present a calculation of the differential two jet cross section in e^+e^- annihilation through next-to-next-to-leading order in the strong coupling constant alpha_s. The calculation is performed using a new method for dealing with real…
Analytic formulae are derived for the complete photon energy spectrum due to QED corrections to fermion pair production in case of a limited angular acceptance for the final state fermions. After a numerical integration over the energy of…
We present complete results for the $O(\alpha_s)$ corrections to the production of a heavy quark pair plus a hard photon, in $e^+ e^-$ annihilation, including both photon and $Z$ intermediate states. Virtual corrections are calculated…
The fragmentation of a light parton i to a jet containing a light energetic hadron h, where the momentum fraction of this hadron as well as the invariant mass of the jet is measured, is described by "fragmenting jet functions". We calculate…
The production of final state photons in deep inelastic scattering originates from photon radiation off leptons or quarks involved in the scattering process. Photon radiation off quarks involves a contribution from the quark-to-photon…
Expressions for Sudakov form factors for heavy quarks are presented. They are used to construct resummed jet rates for up to four jets in $e^+e^-$ annihilation. The coefficients of leading and next-to-leading logarithmic corrections,…
The jet fractions expected in e+e- annihilation are calculated analytically in the leading log approximation up to 6 jet order for both the JADE and Durham algorithms.
Inclusive jet production (e+e- -> e+e- +jet+X) is studied in collisions of quasi-real photons radiated by the LEP beams at e+e- centre-of-mass energies sqrt see from 189 to 209 GeV. Jets are reconstructed using the kp jet algorithm. The…
Data from e+e- annihilation into hadrons at centre-of-mass energies between 91 GeV and 209 GeV collected with the OPAL detector at LEP, are used to study the four-jet rate as a function of the Durham algorithm resolution parameter ycut. The…
We present the convolution integral for fermion pair production in the electroweak standard theory to order O(alpha) including also soft photon exponentiation. The result is complete in the sense that it includes initial and final state…
Hadronic events produced in e+e- collisions by the LEP collider and recorded by the OPAL detector were used to form distributions based on the number of reconstructed jets. The data were collected between 1995 and 2000 and correspond to…
We present new sets of fragmentation functions for D^{*+-} mesons, both at leading and next-to-leading order. They are determined by fitting LEP1 data on inclusive D^{*+-} production in e^+e^- annihilation. In one of the sets, we take the…
The production of a hard and isolated photon accompanied by one or two jets in large-Q2 deep inelastic ep scattering is calculated at next-to-leading order. We include consistently contributions from quark-to-photon fragmentation and study…
Joint probability distributions of photon polarization correlations are computed, as well as those corresponding to the cases when only one of the photon's polarization is measured in $e^{+}e^{-}$ annihilation, in flight, in QED. This…
A complete numerical solution of the evolution equation for parton multiplicities in quark and gluon jets with initial conditions at threshold is presented. Data on both hadron and jet multiplicities in e+e- annihilation are well described…