Joint resummation for gaugino pair production at hadron colliders

We calculate direct gaugino pair production at hadron colliders at next-to-leading order of perturbative QCD, resumming simultaneously large logarithms in the small transverse-momentum and threshold regions to next-to-leading logarithmic accuracy. Numerical predictions are presented for transverse momentum and invariant mass spectra as well as for total cross sections and compared to results obtained at fixed order and with pure transverse-momentum and threshold resummation. We find that our new results are in general in good agreement with the previous ones, but often even more precise.     

Soft-gluon resummation for pseudoscalar Higgs boson production at hadron colliders

We compute the threshold-resummed cross section for pseudo-scalar MSSM Higgs boson production by gluon fusion at hadron colliders. The calculation is performed at next-to-next-to leading logarithmic accuracy. We present results for both the LHC and Tevatron Run II. We analyze the factorization and renormalization scale dependence of the results, finding that after performing the resummation the corresponding cross section can be computed with an accuracy better than 10%.     

Weak interaction effects in top-quark pair production at hadron colliders

Top-quark physics plays an important role at hadron colliders such as the Tevatron at Fermilab or the upcoming Large Hadron Collider (LHC) at CERN. Given the planned experimental precision, detailed theoretical predictions are mandatory. In this article we present analytic results for the complete weak corrections to gluon-induced top-quark pair production – neglecting purely photonic corrections, completing our earlier results for the quark-induced reaction. As an application we discuss top-quark pair production at the Tevatron and LHC. In particular we show that, although they are small for inclusive quantities, weak corrections can be sizeable for differential distributions.     

Z boson pair production and compositeness at large hadron colliders

Z boson pair production at LHC and SSC provides an opportunity to study possible effects due to compositeness in a very high energy domain. We discuss several sources of anomalous effects and give the corresponding bounds on the appropriate compositeness scale. The best bounds are obtained for contact interactions implying longitudinal components of theZ's and for the anomalous couplings of three neutral vector bosons.     

Supersymmetric Higgs boson pair production: Discovery prospects at hadron colliders

We study the potential of hadron colliders in the search for the pair production of neutral Higgs bosons in the framework of the minimal supersymmetric standard model. We perform a detailed signal and background analysis, working out efficient kinematical cuts for the extraction of the signal. The important role of squark loop contributions to the signal is re-emphasized. If the signal is sufficiently enhanced by these contributions, it could even be observable at the next run of the upgraded Tevatron collider in the near future. At the LHC the pair production of light and heavy Higgs bosons might be detectable simultaneously. Received: 23 February 2000 / Revised version: 18 April 2000 / Published online: 31 August 2000     

Central exclusive meson pair production in the perturbative regime at hadron colliders

The central exclusive production (CEP) of heavy resonance states that subsequently decay into meson pairs, \(M\overline{M}\), is an important signature for such processes at hadron colliders. However, there is a potentially important background from the direct QCD production of meson pairs, as mediated for example by the exclusive \(gg\to M\overline{M}\) hard scattering subprocess. This is in fact an interesting process in its own right, testing novel aspects of perturbative QCD technology. We explicitly calculate the \(gg \to M\overline{M}\) helicity amplitudes for different meson states within the hard exclusive formalism, and comment on the application of MHV techniques to the calculation. Using these results, we describe how meson pair CEP can be calculated in the perturbative regime, and present some sample numerical predictions for a variety of final states. We also briefly consider the dominant non-perturbative contributions, which are expected to be important when the meson transverse momentum is small.     

Exotic hadron bound state production at hadron colliders

The non-relativistic wave function framework is applied to study the production and decay of exotic hadrons, which can be effectively described as bound states of other hadrons. Employing the factorized formulation,with the help of event generators, we investigate the production of exotic hadrons in multiproduction processes at high energy hadron colliders. This study provides crucial information for the measurements of the relevant exotic hadrons.     

Charged Higgs production at hadron colliders

We study the production and decay of charged Higgs bosons,H ^±, at TEVATRON and SSC energies as a function of the top massm _t and theH ^± massm _H . We give the cross sections for events arising from bothH ^±→τν andtb decays, together with those of the competing background processes. In particular, form _t >m _H we studyH ^± W ^? andW ⁺ W ^? production and thet→bτν decay.     

Renormalization-group improved prediction for Higgs production at hadron colliders

We use renormalization-group methods in effective field theory to improve the theoretical prediction for the cross section for Higgs-boson production at hadron colliders. In addition to soft-gluon resummation at N³LL, we also resum enhanced contributions of the form (C _A π α _s ) ⁿ , which arise in the analytic continuation of the gluon form factor to time-like momentum transfer. This resummation is achieved by evaluating the matching corrections arising at the Higgs-boson mass scale at a time-like renormalization point μ ²<0, followed by renormalization-group evolution to μ ²>0. We match our resummed result to NNLO fixed-order perturbation theory and give numerical predictions for the total production cross section as a function of the Higgs-boson mass. Resummation effects are significant even at NNLO, where our improved predictions for the cross sections at the Tevatron and the LHC exceed the fixed-order predictions by about 13% and 8%, respectively, for m _H =120 GeV. We also discuss the application of our technique to other time-like processes such as Drell–Yan production, e ⁺ e ⁻→hadrons, and hadronic decays of the Higgs boson.     

High-energy resummation of direct photon production at hadronic colliders

Direct photon production is an important process at hadron colliders, being relevant both for precision measurement of the gluon density, and as background to Higgs and other new physics searches. Here we explore the implications of recently derived results for high-energy resummation of direct photon production for the interpretation of measurements at the Tevatron and the LHC. The effects of resummation are compared to various sources of theoretical uncertainties like PDFs and scale variations. We show how the high-energy resummation procedure stabilizes the logarithmic enhancement of the cross section at high energy which is present at any fixed order in the perturbative expansion starting at NNLO. The effects of high-energy resummation are found to be negligible at Tevatron, while they enhance the cross section by a few percent for pT?10 GeV$p_T?10\text{GeV}$ at the LHC. Our results imply that the discrepancy at small pT$p_T$ between fixed order NLO and Tevatron data cannot be explained by unresummed high-energy contributions.