122854560
Modified minimal subtraction scheme parton densities with NNLO heavy flavor matching conditions
A study is made of charm and bottom flavor matching conditions on parton densities. Starting from an $\overline{\mathrm{MS}}$ three-flavor density set, where the scale $\ensuremath{\mu}l{m}_{c},$ and using the recently derived two-loop matching conditions, we provide a new set of four-flavor parton densities where ${m}_{c}l~\ensuremath{\mu}l{m}_{b}$ and five-flavor densities where $\ensuremath{\mu}g~{m}_{b}.$ The effect of the next-to-next-to-leading order matching conditions on the evolution equations is important for scales just above the transition regions. This includes the small x and small ${Q}^{2}$ domain studied by the H1 and ZEUS experiments at DESY HERA. At small x the effects of the matching conditions never die away even for large ${\ensuremath{\mu}}^{2}.$
123858028
Radiative corrections to the invariant-mass spectrum of a dalitz pair
18918927
Two loop operator matrix elements calculated up to finite terms for polarized deep inelastic lepton - hadron scattering
We present the two-loop corrected operator matrix elements contributing to the scale evolution of the longitudinal spin structure function $g_1(x,Q^2)$ calculated up to finite terms which survive in the limit $\epsilon = N - 4 \to 0$. These terms are needed to renormalize the local operators up to third order in the strong coupling constant $\alpha_s$. Further the expressions for the two-loop corrected operator matrix elements can be inserted into one loop graphs to obtain a part of the third order contributions to these matrix elements. This work is a first step in obtaining the third order anomalous dimensions so that a complete next-to-next-to-leading order (NNLO) analysis of the above mentioned structure function can be carried out. In our calculation particular attention is paid to the renormalization constant which is needed to restore the Ward-identities violated by the HVBM prescription for the $\gamma_5$-matrix in $N$-dimensional regularization.
18923537
Higgs Production at NNLO
We describe the calculation of inclusive Higgs boson production at hadronic colliders at next-to-next-to-leading order (NNLO) in perturbative quantum chromodynamics. We have used the technique developed in reference [4]. Our results agree with those published earlier in the literature.
123015361
Electromagnetic production of trimuons in muon scattering: Bethe-Heitler reactions with muon and heavy-lepton pairs
We analyze the Bethe-Heitler production of muon and heavy-lepton pairs using high-energy muon beams on a variety of targets. We give results for coherent production from a nucleus, for incoherent production from individual protons and neutrons, and for deep-inelastic production. Differential distributions are presented for the final leptons and the effects of experimental cuts are considered. This work complements our previous study of trimuon production via muon radiation, Compton radiation, and hadronic final-state interactions.
2742768
The Heavy-Flavour Contribution to Proton Structure
We present theoretical and experimental considerations pertaining to deeply inelastic heavyflavour production at HERA. The various theoretical uncertainties in the cross section calculation are discussed. Cuts are imposed to determine the fraction of charm production accessible to the detectors. The production of charm at asymptotic Q 2 and bottom production are also covered. Experimental aspects include current charm production data analysis and prospects for future analyses including anticipated high precision and distinguishing photon-gluon fusion charm events from excitation from the charm parton density. The feasibility of measuring
16011903
First observation of five charmless hadronic B decays
There has been much progress in measurements of charmless hadronic B decays during 1997. Building on the previous indications from CLEO and LEP, CLEO now has clear signals in five exclusive final states: K^+\pi^, K^0\pi^+, etapr K^+, etapr K^0, and omega K^+. The branching fractions for the etapr K modes are several times larger than the others. A similar strikingly large signal has been seen in the inclusive decay, B->etapr X_S. All of these signals would appear to be dominated by hadronic penguin processes. (Invited talk presented at the Seventh International Symposium On Heavy Flavor Physics, Santa Barbara, CA, July 7-11, 1997.)
120135663
Studies of tau decay modes with K0 mesons from CLEO
We examine five final states involving K 0 mesons, presenting branching fractions for the decays τ → K 0 πν τ , τ → K 0 ππ 0 ν τ , τ → K 0 Kν τ , τ → K 0 Kπ 0 ν τ , and τ → K s K s hν τ . The mass spectra provide evidence for the dominant role of K * in Kπ decays and K 1 in Kππ modes. We find evidence for a significant K * K contribution to the KKπ decays.
118976257
Quarks and Antiquarks in Nuclei
The Chiral Quark-Soliton model provides the quark and antiquark substructure of the nucleon, which is embedded in nuclear matter. This provides a new way to asses the effects of the nuclear medium on the nucleon. We calculate nuclear binding and saturation, describe the European Muon Collaboration (EMC) effect consistently with Drell-Yan experiments, and predict modifications to the polarized parton distributions. We also calculate the electromagnetic form factors of a bound proton, and find significant modifications of the electromagnetic form factors in the nuclear environment. In every case, the properties of the sea of quark-antiquark pairs in the nucleon are very important, and serve to mitigate the valence quark effect. The changes in the sea quarks when the nucleon is immersed in the nuclear medium are the primary mode by which consistency is maintained with experimental constraints (Drell-Yan data, magnetic moment), while still maintaining a significant effect needed to explain the deep inelastic scattering and polarization transfer data.
119434142
Role of the nuclear vector potential in deep inelastic scattering
We study the influence of the strong nuclear vector potential, treated using the mean-field approximation, in deep inelastic scattering. A physically consistent treatment of the electromagnetic current operator, combined with the use of the operator product expansion is presented and discussed.
124046826
CHARMLESS HADRONIC B DECAYS WITH THE FULL CLEO DATA SAMPLE