Measurement of D s ± production asymmetry in pp collisions at s = 7 √s=7 and 8 TeV

Abstract

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>The inclusive <jats:italic>D</jats:italic> <jats:sub> <jats:italic>s</jats:italic> </jats:sub> <jats:sup>±</jats:sup> production asymmetry is measured in <jats:italic>pp</jats:italic> collisions collected by the LHCb experiment at centre-of-mass energies of <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ \sqrt{s}=7 $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>7</mml:mn> </mml:math> </jats:alternatives> </jats:inline-formula> and 8 TeV. Promptly produced <jats:italic>D</jats:italic> <jats:sub> <jats:italic>s</jats:italic> </jats:sub> <jats:sup>±</jats:sup> mesons are used, which decay as <jats:italic>D</jats:italic> <jats:sub> <jats:italic>s</jats:italic> </jats:sub> <jats:sup>±</jats:sup> → <jats:italic>ϕ</jats:italic>π<jats:sup>±</jats:sup>, with <jats:italic>ϕ</jats:italic> → <jats:italic>K</jats:italic> <jats:sup>+</jats:sup> <jats:italic>K</jats:italic> <jats:sup>−</jats:sup>. The measurement is performed in bins of transverse momentum, <jats:italic>p</jats:italic> <jats:sub>T</jats:sub>, and rapidity, <jats:italic>y</jats:italic>, covering the range 2<jats:italic>.</jats:italic>5 <jats:italic>&lt; p</jats:italic> <jats:sub>T</jats:sub> <jats:italic>&lt;</jats:italic> 25<jats:italic>.</jats:italic>0 GeV/c and 2<jats:italic>.</jats:italic>0 <jats:italic>&lt; y &lt;</jats:italic> 4<jats:italic>.</jats:italic>5. No kinematic dependence is observed. Evidence of nonzero <jats:italic>D</jats:italic> <jats:sub> <jats:italic>s</jats:italic> </jats:sub> <jats:sup>±</jats:sup> production asymmetry is found with a significance of 3.3 standard deviations. </jats:p>