Measurements of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>D</mml:mi><mml:mn>0</mml:mn></mml:msup></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>D</mml:mi><mml:mo mathvariant="bold">*</mml:mo></mml:msup></mml:math>production in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi><mml:mo mathvariant="bold">+</mml:mo><mml:mi>p</mml:mi></mml:math>collisions at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo mathvariant="bold">=</mml:mo><mml:mn>200</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>GeV</mml:mi></mml:math>
Abstract
We report measurements of charmed-hadron $({D}^{0},{D}^{*})$ production cross sections at midrapidity in $p+p$ collisions at a center-of-mass energy of 200 GeV by the STAR experiment. Charmed hadrons were reconstructed via the hadronic decays ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$, ${D}^{*+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}$ and their charge conjugates, covering the ${p}_{T}$ range of $0.6--2.0$ and $2.0--6.0\text{ }\text{ }\mathrm{GeV}/c$ for ${D}^{0}$ and ${D}^{*+}$, respectively. From this analysis, the charm-pair production cross section at midrapidity is $d\ensuremath{\sigma}/dy{|}_{y=0}^{c\overline{c}}=170\ifmmode\pm\else\textpm\fi{}45(\mathrm{stat}{)}_{\ensuremath{-}59}^{+38}(\mathrm{sys})\text{ }\text{ }\ensuremath{\mu}\mathrm{b}$. The extracted charm-pair cross section is compared to perturbative QCD calculations. The transverse momentum differential cross section is found to be consistent with the upper bound of a fixed-order next-to-leading logarithm calculation.
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