Measurement of the Muon Charge Asymmetry in Inclusive $pp \to W+X$ Production at $\sqrt s =$ 7 TeV and an Improved Determination of Light Parton Distribution Functions
<p>Measurements of the muon charge asymmetry in inclusive <inline-formula><mml:math display="inline"><mml:mrow><mml:mi>p</mml:mi><mml:mi>p</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>W</mml:mi><mml:mo>+</mml:mo><mml:mi>X</mml:mi></mml:mrow></mml:math></inline-formula> production at <inline-formula><mml:math display="inline"><mml:mrow><mml:msqrt><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>7</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>TeV</mml:mi></mml:mrow></mml:math></inline-formula> are presented. The data sample corresponds to an integrated luminosity of <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>4.7</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:msup><mml:mrow><mml:mi>fb</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula> recorded with the CMS detector at the LHC. With a sample of more than 20 million <inline-formula><mml:math display="inline"><mml:mi>W</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>μ</mml:mi><mml:mi>ν</mml:mi></mml:math></inline-formula> events, the statistical precision is greatly improved in comparison to previous measurements. These new results provide additional constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable <inline-formula><mml:math display="inline"><mml:mi>x</mml:mi></mml:math></inline-formula> from <inline-formula><mml:math display="inline"><mml:msup><mml:mn>10</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msup></mml:math></inline-formula> to <inline-formula><mml:math display="inline"><mml:msup><mml:mn>10</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:math></inline-formula>. These measurements and the recent CMS measurement of associated <inline-formula><mml:math display="inline"><mml:mrow><mml:mi>W</mml:mi><mml:mo>+</mml:mo><mml:mtext>charm</mml:mtext></mml:mrow></mml:math></inline-formula> production are used together with the cross sections for inclusive deep inelastic <inline-formula><mml:math display="inline"><mml:msup><mml:mi>e</mml:mi><mml:mo>±</mml:mo></mml:msup><mml:mi>p</mml:mi></mml:math></inline-formula> scattering at HERA in a next-to-leading-order QCD analysis. The determination of the valence quark distributions is improved, and the strange-quark distribution is probed directly through the leading-order process <inline-formula><mml:math display="inline"><mml:mrow><mml:mi>g</mml:mi><mml:mo>+</mml:mo><mml:mi>s</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>W</mml:mi><mml:mo>+</mml:mo><mml:mi>c</mml:mi></mml:mrow></mml:math></inline-formula> in proton-proton collisions at the LHC.</p>
arXiv_1312.6283.pdf
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fermilab-pub-13-608-cms.pdf
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