arXiv subjects

E. W. N. Glover

Publications and source records attributed to E. W. N. Glover.

149 records · Page 9Linked to original sources

arXiv1995

The Determination of $α_S$ at Hadron Colliders

Hadron colliders offer a unique opportunity to test perturbative QCD because, rather than producing events at a specific beam energy, the dynamics of the hard scattering is probed simultaneously at a wide range of momentum transfers. This makes the determination of $\al$ and the parton density functions (PDF) at hadron colliders particularly interesting. In this paper we restrict ourselves to extracting $\al$ for a given PDF at a scale which is directly related to the transverse energy produced in the collision. As an example, we focus on the single jet inclusive transverse energy distribution and use the published '88-'89 CDF data with an integrated luminosity of 4.2 pb$^{-1}$. The evolution of the coupling constant over a wide range of scales (from 30~GeV to 500~GeV) is clearly shown and is in agreement with the QCD expectation. The data to be obtained in the current Tevatron run (expected to be well in excess 100 pb$^{-1}$ for both the CDF and DØ experiments) will significantly decrease the experimental errors.

hep-ph↗

arXiv1994

The Inclusive Two Jet Triply Differential Cross Section

We study the inclusive two jet triply differential cross section $d^3σ/dE_Tdη_1dη_2$ at Fermilab energies. Different $η_1$ and $η_2$ pseudorapidity regions are directly related to both the parton level matrix elements and the parton densities at leading order. We present the next-to-leading order [${\cal O}(α_s^3)$] corrections and show that the shape of the distribution at fixed transverse energy $E_T$ is a particularly powerful tool for constraining the parton distributions at small to moderate $x$ values. We investigate the renormalisation/factorisation scale uncertainty present in the normalisation and shape of the distribution at next-to-leading order. We discuss specific slices of the distribution, the same-side/opposite side ratio and the signed pseudorapidity distribution, in detail and compare them with preliminary experimental data.

hep-ph↗

arXiv1994

The Energy-Energy Correlation Function Revisited

The ${\cal O}(α_s^2)$ coefficient of the energy-energy correlation function (EEC) has been calculated by four groups with differing results. This discrepancy has lead to some confusion over how to measure the strong coupling constant using the EEC and the asymmetry of the energy-energy correlation function (AEEC) in electron-positron annihilation at the $Z$ resonance. For example, SLD average the four values of $α_s$ extracted from each of the different calculations. To resolve this situation, we present a new calculation of this coefficient using three separate numerical techniques to cancel the infrared poles. All three methods agree with each other and confirm the results of Kunszt and Nason that form the benchmark for other ${\cal O}(α_s^2)$ quantities. As a consequence, the central values and theoretical errors of the strong coupling constant derived by SLD from the EEC and AEEC are altered. Using the SLD data, we find, $α_s^{EEC}(M_Z^2) = 0.125^{+0.002}_{-0.003}~({\rm exp.}) \pm 0.012 ~({\rm theory})$ and $α_s^{AEEC}(M_Z^2) = 0.114\pm 0.005~({\rm exp.}) \pm 0.004 ~({\rm theory})$.

hep-ph↗

arXiv1994

The Two-Jet Differential Cross Section at ${\cal O}(α_s^3)$ in Hadron Collisions

We study the two-jet inclusive cross section via the triply differential distribution $d^3σ/dE_{T}dη_1 dη_2$ to next-to-leading order in QCD. The predicted distributions can be compared directly with forthcoming data from the D0 and CDF experiments at Fermilab. We discuss differences with the leading-order predictions, and examine uncertainties due to the choice of scale and parton density.

hep-ph↗

arXiv1993

Single Lepton Production at Large Transverse Momentum

We study the production of single isolated leptons at large transverse momentum, $p_T^\ell > M_W/2$. The dominant source of such leptons is production of an on-shell $W$ boson recoiling against a hard jet. Vetoing this jet forces the $W$ boson to be produced off resonance and significantly reduces the standard model cross section, thereby enhancing the discovery prospects for non standard model physics. A significant number of events have the topologically interesting signature of a large $p_T$ lepton balancing a jet with little measured missing transverse energy.

hep-ph↗