$\Xi^{0}_{c}$ production in semi-leptonic decay channel in pp collisions at 5 TeV

The ALICE detector at the Large Hadron Collider (LHC) is optimised for the investigation of the Quark-Gluon Plasma (QGP) created in heavy-ion collisons. Charm quarks are effective probes to elucidate the properties of the QGP. They are dominantly produced at the initial stage of the collisons via hard partonic scattering processes and experience the whole evolution of the system.

Charm-baryon measurements provides unique insight into hadronisation prcesses. In particular, the baryon-to-meson ratio is expected to be enhanced if charm quarks hadronise via recombination with the surroudning light quarks in the QGP. Moreover, in such a recombination picture, the baryon-to-meson ratio could further be enhanced in the presence of diquark bound states in the hot and dense QCD medium. Measurements of charm-baryon production in pp collisions are essebtial to establish a baseline for studies in Pb-Pb collisions. In addition, the measuremnt in pp collisons provide critical tests of pQCD calculations and for models of charm hadronisation in vacuum. 

 

In this paper, the $p_{\rm T}$ differential cross section of the $\Xi^{0}_{\rm c}$ baryon measured in the decay channel $\Xi^{0}_{\rm c} \rightarrow e\Xi\nu$ in pp collisions at $\sqrt s = 5.02$ TeV will be shown.

 

Submitted to: JHEP
e-Print: arXiv:2105.05616 | PDF | inSPIRE

Figure 1

Left panel: $n_{\sigma\textrm{,e}}^\textrm{TPC}$ distribution as a function of the electron \pt after applying the particle identification criteria on the TOF signal (see text for details). Right panel: invariant mass distribution of $\Xi^{-} \rightarrow \pi^{-}\Lambda$ (and charge conjugate) candidates integrated over $ p_{\rm T}^{\Xi^{-}}$ The arrow indicates the world average $\Xi^{-}$ mass~ and the dashed lines define the interval in which the $\Xi^{-}$ candidates are selected for the $\Xi^0_{\rm c}$ reconstruction (see text for details).

Figure 3

Correlation matrix between the generated $\Xi^0_{\rm c}$-baryon \pt and the reconstructed $ {\rm e}^{+}\Xi^{-}$ pair \pt, obtained from the simulation based on PYTHIA 8 described in the text.

Figure 4

Left panel: product of acceptance and efficiency for prompt and feed-down $\Xi^0_{\rm c}$ baryons in pp collisions at $\sqrt{s} =$ 5.02 TeV as a function of\pt. Right panel: fraction of prompt $\Xi^0_{\rm c}$ baryons in the raw yield ($f_{\rm prompt}$) as a function of \pt. The systematic uncertainties of $f_{\rm prompt}$ are shown as boxes.

Figure 5

Left panel: \pt-differential production cross sections of prompt $\Xi^0_{\rm c}$ baryons in pp collisions at $\sqrt{s}$~=~5.02~TeV and 13 TeV~ and of inclusive $\Xi^0_{\rm c}$ baryons in pp collisions at $\sqrt{s}$~=~7~TeV ~ with updated decay BR as discussed in the text. The uncertainty of the BR of the cross sections of prompt $\Xi^0_{\rm c}$ baryons in pp collisions at $\sqrt{s}$~=~13 TeV is lower because it consists in the combination of two different decay channels ($\Xi^0_{\rm c} \rightarrow {\rm e}^{+}\Xi^{-}\nu_{\rm e}$ and $\Xi^0_{\rm c} \rightarrow {\pi}^{+}\Xi^{-}$)~ Right panel: $\Xi^0_{\rm c}$/${\rm D^0}$ ratio measured in pp collisions at $\sqrt{s}$~=~5.02~TeV, compared with the measurements at $\sqrt{s}$~=~7~TeV~ and $\sqrt{s}$~=~13~TeV~. The uncertainty of the BR of ${\rm D^0}$ and $\Xi^0_{\rm c}$ are shown as shaded boxes.

Figure 6

Left panel: \pt-differential production cross section of prompt $\Xi^0_{\rm c}$ baryons in pp collisions at $\sqrt{s}$~=~5.02~TeV compared with model calculations~. Right panel: $\Xi^0_{\rm c}/{\rm D^0}$ ratio as a function of \pt measured in pp collisions at $\sqrt{s}$~=~5.02~TeV compared with model calculations~ (see text for details).