First Measurement of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi mathvariant="normal">Λ</mml:mi><mml:mi>c</mml:mi></mml:msub></mml:math> Baryon Production in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>Au</mml:mi><mml:mo>+</mml:mo><mml:mi>Au</mml:mi></mml:mrow></mml:math> Collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msqrt><mml:mrow><mml:msub><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mi>N</mml:mi><mml:mi>N</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>200</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>GeV</mml:mi></mml:mrow></mml:math>
J. Adam, L. Adamczyk, J. R. Adams, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, D. M. Anderson, A. Aparin, E. C. Aschenauer, M. U. Ashraf, F. G. Atetalla, A. Attri, G. S. Averichev, V. Bairathi, K. N. Barish, A. Behera, R. Bellwied, A. Bhasin, J. Bielčík, J. Bielčíková, L. C. Bland, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, J. M. Butterworth, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, I. Chakaberia, P. Chaloupka, B. K. Chan, F-H. Chang, Z. Chang, N. Chankova-Bunzarova, A. Chatterjee, D. Chen, J. H. Chen, X. Chen, Z. Chen, J. Cheng, M. Cherney, M. Chevalier, S. Choudhury, W. Christie, H. J. Crawford, M. Csanád, M. Daugherity, Т. Г. Дедович, I. M. Deppner, A. A. Derevschikov, L. Didenko, X. Dong, J. L. Drachenberg, J. C. Dunlop, T. Edmonds, N. Elsey, J. Engelage, G. Eppley, R. Esha, S. Esumi, O. Evdokimov, J. Ewigleben, O. Eyser, R. Fatemi, S. Fazio, P. Federic, J. Fedorišin, C. Feng, Y. Feng, P. Filip, E. Finch, Y. Fisyak, A. Francisco, Ł. Fulek, C. A. Gagliardi, T. Galatyuk, F. J. M. Geurts, S. M. Gibson, K. Gopal, D. Grosnick, W. Guryn, A. I. Hamad, A. Hamed, J. W. Harris, W. He, X. H. He, S. Heppelmann, S. Heppelmann, N. Herrmann, E. Hoffman, L. Holub, Y. Hong, S. Horvat, Y. Hu, H. Z. Huang, S. L. Huang, T. Huang, X. T. Huang
Abstract
We report on the first measurement of the charmed baryon ${\mathrm{\ensuremath{\Lambda}}}_{c}^{\ifmmode\pm\else\textpm\fi{}}$ production at midrapidity ($|y|<1$) in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{{s}_{\mathrm{NN}}}=200\text{ }\text{ }\mathrm{GeV}$ collected by the STAR experiment at the Relativistic Heavy Ion Collider. The ${\mathrm{\ensuremath{\Lambda}}}_{c}/{D}^{0}$ [denoting $({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}+{\mathrm{\ensuremath{\Lambda}}}_{c}^{\ensuremath{-}})/({D}^{0}+{\overline{D}}^{0})$] yield ratio is measured to be $1.08\ifmmode\pm\else\textpm\fi{}0.16\text{ }\text{ }(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.26\text{ }\text{ }(\mathrm{sys})$ in the 0%--20% most central $\mathrm{Au}+\mathrm{Au}$ collisions for the transverse momentum (${p}_{T}$) range $3<{p}_{T}<6\text{ }\text{ }\mathrm{GeV}/c$. This is significantly larger than the pythia model calculations for $p+p$ collisions. The measured ${\mathrm{\ensuremath{\Lambda}}}_{c}/{D}^{0}$ ratio, as a function of ${p}_{T}$ and collision centrality, is comparable to the baryon-to-meson ratios for light and strange hadrons in $\mathrm{Au}+\mathrm{Au}$ collisions. Model calculations including coalescence hadronization for charmed baryon and meson formation reproduce the features of our measured ${\mathrm{\ensuremath{\Lambda}}}_{c}/{D}^{0}$ ratio.