Drell-Yan invariant mass spectrum, normalised to the Z resonance region.

Read the paper: QCD-10-037

The measured Drell-Yan production rates, normalised to the production rates in the Z-boson region, show good agreement with the theoretical predictions.

The Drell-Yan process occurs when a quark from one of the colliding protons annihilates with an anti-quark from a proton travelling in the opposite direction and is converted into a photon or a Z boson, which decays into two leptons. Studying this process is very important because:

  1. Comparisons between theoretical calculations and experimental measurements provide stringent tests for the theory of perturbative Quantum Chromodynamics (pQCD).
  2. Comparisons also provide significant constraints on the evaluation of parton distribution functions (PDFs).
  3. It is a key background in the searches for new phenomena, including searches for the Higgs boson.

For this paper, the data samples chosen were ones in which the photon or Z boson formed from the quark annihilation decayed into pairs of electrons or muons.

Group: Electroweak Physics (EWK)
Collisions: pp
Centre-of-mass energy: 7 TeV
Data sample: 35.9 ± 1.4 pb–1
Dates of data collection: 2010
Di-lepton invariant mass (Mll) range covered: 15–600 GeV
Submitted to: Journal of High Energy Physics (JHEP)