QCD Results from the Fermilab Tevatron proton-antiproton Collider

TL;DR

This paper reviews recent QCD measurements from Fermilab's Tevatron collider, testing perturbative QCD, constraining new physics, and exploring phenomena like double parton scattering and jet formation at 1.96 TeV.

Contribution

It provides new measurements of the strong coupling constant, investigates double parton scattering, and examines jet and underlying event properties, enhancing understanding of QCD at TeV energies.

Findings

Precise alpha_s(m_Z) measurement: 0.1161^{+0.0041}_{-0.0048}

Double parton scattering cross section: sigma_{eff} = 16.4 +- 2.3 mb

NLO pQCD fails to describe low-energy photon production

Abstract

Selected recent quantum chromodynamics (QCD) measurements are reviewed for Fermilab Run II Tevatron proton-antiproton collisions studied by the Collider Detector at Fermilab (CDF) and DZero Collaborations at a centre-of-mass energy of sqrt{s}=1.96 TeV. Tantamount to Rutherford scattering studies at the TeV scale, inclusive jet and dijet production cross-section measurements are used to seek and constrain new particle physics phenomena, test perturbative QCD calculations, inform parton distribution function (PDF) determinations, and extract a precise value of the strong coupling constant, alpha_s(m_Z) = 0.1161^{+0.0041}_{-0.0048}. Inclusive photon production cross-section measurements reveal an inability of next-to-leading-order (NLO) perturbative QCD (pQCD) calculations to describe low-energy photons arising directly in the hard scatter. Events with gamma + 3-jet configurations are used to measure the increasingly important double parton scattering (DPS) phenomenon, with an obtained effective interaction cross section of sigma_{eff} = 16.4 +- 2.3 mb. Observations of central exclusive particle production demonstrate the viability of observing the Standard Model Higgs boson using similar techniques at the Large Hadron Collider (LHC). Three areas of inquiry into lower energy QCD, crucial to understanding high-energy collider phenomena, are discussed: the examination of intra-jet track kinematics to infer that jet formation is dominated by pQCD, and not hadronization, effects; detailed studies of the underlying event and its universality; and inclusive minimum-bias charged-particle momentum and multiplicity measurements, which are shown to challenge the Monte Carlo generators.