14067577
NLO corrections to differential cross sections for pseudo-scalar Higgs boson production
Abstract We have computed the full next-to-leading (NLO) QCD corrections to the differential distributions d 2 σ/(dp T dy) for pseudo-scalar Higgs (A) production at large hadron colliders. This calculation has been carried out using the effective Lagrangian approach which is valid as long as the mass of the pseudo-scalar Higgs boson m A and its transverse momentum p T do not exceed the top-quark mass  m t . The shape of the distributions hardly differ from those obtained for scalar Higgs (H) production because, apart from the overall coupling constant and mass, there are only small differences between the partonic differential distributions for scalar and pseudo-scalar production. Therefore, there are only differences in the magnitudes of the hadronic differential distributions which can be mainly attributed to the unknown mixing angle β describing the pseudo-scalar Higgs coupling to the top quarks.
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.
123858028
Radiative corrections to the invariant-mass spectrum of a dalitz pair
119810153
Comparison of trimuon production mechanisms
We compare the predictions of six models for neutrino (and antineutrino) production of trimuon events. In particular, results are given for models based on heavy-charged-lepton decays, heavy-neutral- lepton decays together with heavy-quark decays, diffractive production and decay of heavy-quark pairs, heavy-quark cascade decays, the decays of Higgs mesons, and the radiative production of muon pairs. Our comparison should help to unravel the sources of the trimuon events detected at Fermilab and CERN. We also examine the probability of explaining the so-called superevents in which the muons are extremely energetic.
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
120150178
Measurement of anomalous muon pair production in electron-positron annihilations
We have observed 16 events of the type ..mu../sup +/..mu../sup -/ + (missing energy and momentum) from e/sup +/e/sup -/ annihilations at center-of-mass energies between 6.4 and 7.4 GeV. Taking into account QED backgrounds, we find an excess of 11 anomalous dimuon events. If these are attributed to the production and subsequent decay of a pair of heavy leptons L/sup + -/, we obtain the muonic braching ratio B ((L/sup +/ ..-->.. ..mu../sup +/..nu../sub ..mu../nu-bar/sub L/)/ (L/sup +/ ..-->.. all)) = 0.22/sup +0.07//sub -0.08/.
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.
121273996
A study of double tagged two-photon reactions at spear☆
Abstract We have identified 262 doubly tagged two-photon events. A subset of the data shows an enhancement of 21 events in the inclusive two-photon mass squared distribution between 0.8 and 2.2 GeV 2 . If these events result from spin 2 resonance production then Γ γγ = 9.5 ± 3.9 ± 2.4 keV (statistical and systematic). From another subset of 58 events in which the final state could be classified we determine the two-photon hadron to muon cross section ratio R γγ = 1.1 ± 0.3 ± 0.3.
124046826
CHARMLESS HADRONIC B DECAYS WITH THE FULL CLEO DATA SAMPLE
14586426
Review of New Rare Hadronic B-decay Results
We present a new result from Belle and many new results from BABAR for rare hadronic B decays. These include measurements of decays involving baryons, a Dalitz plot analysis of the three-charged-kaon system, many new results for B decays to eta'X and omegaX, and a limit for the decay B-> a_1 rho. Measurements of the vector-vector decays B->rhoKstar and B->omegaKstar are helping to understand the value of the longitudinal polarization fraction for these B->VV decays.