Measurement of beauty and charm production in pp collisions at $$ \sqrt{s} $$ = 5.02 TeV via non-prompt and prompt D mesons
抄録
<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>The <jats:italic>p</jats:italic><jats:sub>T</jats:sub>-differential production cross sections of prompt and non-prompt (produced in beauty-hadron decays) D mesons were measured by the ALICE experiment at midrapidity (<jats:italic>|</jats:italic><jats:italic>y</jats:italic><jats:italic>|</jats:italic><jats:italic><</jats:italic> 0<jats:italic>.</jats:italic>5) in proton-proton collisions at <jats:inline-formula><jats:alternatives><jats:tex-math>$$ \sqrt{s} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math></jats:alternatives></jats:inline-formula> = 5<jats:italic>.</jats:italic>02 TeV. The data sample used in the analysis corresponds to an integrated luminosity of (19<jats:italic>.</jats:italic>3 <jats:italic>±</jats:italic> 0<jats:italic>.</jats:italic>4) nb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>. D mesons were reconstructed from their decays D<jats:sup>0</jats:sup><jats:italic>→</jats:italic> K<jats:sup><jats:italic>−</jats:italic></jats:sup>π<jats:sup>+</jats:sup>, D<jats:sup>+</jats:sup><jats:italic>→</jats:italic> K<jats:sup><jats:italic>−</jats:italic></jats:sup>π<jats:sup>+</jats:sup>π<jats:sup>+</jats:sup>, and <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {\mathrm{D}}_{\mathrm{s}}^{+}\to \upphi {\uppi}^{+}\to {\mathrm{K}}^{-}{\mathrm{K}}^{+}{\uppi}^{+} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mo>→</mml:mo> <mml:mi>ϕ</mml:mi> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>−</mml:mo> </mml:msup> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> </mml:math></jats:alternatives></jats:inline-formula> and their charge conjugates. Compared to previous measurements in the same rapidity region, the cross sections of prompt D<jats:sup>+</jats:sup> and <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {\mathrm{D}}_{\mathrm{s}}^{+} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula> mesons have an extended <jats:italic>p</jats:italic><jats:sub>T</jats:sub> coverage and total uncertainties reduced by a factor ranging from 1.05 to 1.6, depending on <jats:italic>p</jats:italic><jats:sub>T</jats:sub>, allowing for a more precise determination of their <jats:italic>p</jats:italic><jats:sub>T</jats:sub>-integrated cross sections. The results are well described by perturbative QCD calculations. The fragmentation fraction of heavy quarks to strange mesons divided by the one to non-strange mesons, <jats:italic>f</jats:italic><jats:sub>s</jats:sub><jats:italic>/</jats:italic>(<jats:italic>f</jats:italic><jats:sub>u</jats:sub> + <jats:italic>f</jats:italic><jats:sub>d</jats:sub>), is compatible for charm and beauty quarks and with previous measurements at different centre-of-mass energies and collision systems. The <jats:inline-formula><jats:alternatives><jats:tex-math>$$ \mathrm{b}\overline{\mathrm{b}} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>b</mml:mi> <mml:mover> <mml:mi>b</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math></jats:alternatives></jats:inline-formula> production cross section per rapidity unit at midrapidity, estimated from non-prompt D-meson measurements, is <jats:inline-formula><jats:alternatives><jats:tex-math>$$ \mathrm{d}{\sigma}_{\mathrm{b}\overline{\mathrm{b}}}/\mathrm{d}y\left|{}_{\left|\mathrm{y}\right|<0.5}=34.5\pm 2.4{\left(\mathrm{stat}\right)}_{-2.9}^{+4.7}\left(\mathrm{tot}.\mathrm{syst}\right)\right. $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>d</mml:mi> <mml:msub> <mml:mi>σ</mml:mi> <mml:mrow> <mml:mi>b</mml:mi> <mml:mover> <mml:mi>b</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:mrow> </mml:msub> <mml:mo>/</mml:mo> <mml:mi>d</mml:mi> <mml:mi>y</mml:mi> <mml:mfenced> <mml:mrow> <mml:msub> <mml:mrow /> <mml:mrow> <mml:mfenced> <mml:mi>y</mml:mi> </mml:mfenced> <mml:mo><</mml:mo> <mml:mn>0.5</mml:mn> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>34.5</mml:mn> <mml:mo>±</mml:mo> <mml:mn>2.4</mml:mn> <mml:msubsup> <mml:mfenced> <mml:mtext>stat</mml:mtext> </mml:mfenced> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>2.9</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>4.7</mml:mn> </mml:mrow> </mml:msubsup> <mml:mfenced> <mml:mrow> <mml:mi>tot</mml:mi> <mml:mo>.</mml:mo> <mml:mtext>syst</mml:mtext> </mml:mrow> </mml:mfenced> </mml:mrow> </mml:mfenced> </mml:math></jats:alternatives></jats:inline-formula> μb. It is compatible with previous measurements at the same centre-of-mass energy and with the cross section pre- dicted by perturbative QCD calculations.</jats:p>
収録刊行物
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- Journal of High Energy Physics
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Journal of High Energy Physics 2021 (5), 2021-05
Springer Science and Business Media LLC