Measurement of the W → τν<SUB>τ</SUB> cross section in pp collisions at √s = 7 TeV with the ATLAS experiment

Abstract

The cross section for the production of W bosons with subsequent decay W → τντ is measured with the ATLAS detector at the LHC. The analysis is based on a data sample that was recorded in 2010 at a proton–proton center-of-mass energy of √s = 7 TeV and corresponds to an integrated luminosity of 34 pb−1. The cross section is measured in a region of high detector acceptance and then extrapolated to the full phase space. The product of the total W production cross section and the W → τντ branching ratio is measured to be <math><msubsup is="true"><mi is="true">σ</mi><mrow is="true"><mi is="true">W</mi><mo is="true">→</mo><mi is="true">τ</mi><msub is="true"><mi is="true">ν</mi><mi is="true">τ</mi></msub></mrow><mi mathvariant="normal" is="true">tot</mi></msubsup><mo is="true">=</mo><mn is="true">11.1</mn><mo is="true">±</mo><mn is="true">0.3</mn><mspace width="0.25em" is="true"></mspace><mo stretchy="false" is="true">(</mo><mtext is="true">stat</mtext><mo stretchy="false" is="true">)</mo><mo is="true">±</mo><mn is="true">1.7</mn><mspace width="0.25em" is="true"></mspace><mo stretchy="false" is="true">(</mo><mtext is="true">syst</mtext><mo stretchy="false" is="true">)</mo><mo is="true">±</mo><mn is="true">0.4</mn><mspace width="0.25em" is="true"></mspace><mo stretchy="false" is="true">(</mo><mtext is="true">lumi</mtext><mo stretchy="false" is="true">)</mo><mtext is="true"> nb</mtext></math>.