The prompt production of the charm baryon Λc+ and the Λc+/D0 production ratios were measured at midrapidity with the ALICE detector in pp and p-Pb collisions at sNN=5.02 TeV. These new measurements show a clear decrease of the Λc+/D0 ratio with increasing transverse momentum (pT) in both collision systems in the range 2<12 GeV/c, exhibiting similarities with the light-flavor baryon-to-meson ratios p/π and Λ/KS0. At low pT, predictions that include additional color-reconnection mechanisms beyond the leading-color approximation, assume the existence of additional higher-mass charm-baryon states, or include hadronization via coalescence can describe the data, while predictions driven by charm-quark fragmentation processes measured in e+e- and e-p collisions significantly underestimate the data. The results presented in this Letter provide significant evidence that the established assumption of universality (colliding-system independence) of parton-to-hadron fragmentation is not sufficient to describe charm-baryon production in hadronic collisions at LHC energies.
Λc+ Production and Baryon-to-Meson Ratios in pp and p -Pb Collisions at sNN =5.02 TeV at the LHC
Cortese P.;Ramello L.;Sitta M.;
2021-01-01
Abstract
The prompt production of the charm baryon Λc+ and the Λc+/D0 production ratios were measured at midrapidity with the ALICE detector in pp and p-Pb collisions at sNN=5.02 TeV. These new measurements show a clear decrease of the Λc+/D0 ratio with increasing transverse momentum (pT) in both collision systems in the range 2<12 GeV/c, exhibiting similarities with the light-flavor baryon-to-meson ratios p/π and Λ/KS0. At low pT, predictions that include additional color-reconnection mechanisms beyond the leading-color approximation, assume the existence of additional higher-mass charm-baryon states, or include hadronization via coalescence can describe the data, while predictions driven by charm-quark fragmentation processes measured in e+e- and e-p collisions significantly underestimate the data. The results presented in this Letter provide significant evidence that the established assumption of universality (colliding-system independence) of parton-to-hadron fragmentation is not sufficient to describe charm-baryon production in hadronic collisions at LHC energies.File | Dimensione | Formato | |
---|---|---|---|
PhysRevLett.127.202301.pdf
file ad accesso aperto
Descrizione: Articolo
Tipologia:
Versione Editoriale (PDF)
Licenza:
Creative commons
Dimensione
323.83 kB
Formato
Adobe PDF
|
323.83 kB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.