26-30 July 2021
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Europe/Berlin timezone

Charm cross section and fragmentation fractions in pp collisions with ALICE (12'+3')

27 Jul 2021, 10:15
15m
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Parallel session talk QCD and Hadronic Physics T06: QCD and Hadronic Physics

Speaker

Luigi Dello Stritto (Università degli Studi di Salerno)

Description

In this contribution, we present the latest measurements of $\Lambda^{+}_{\rm c}$, $\Xi^{+,0}_{\rm c}$, $\Sigma^{0,++}_{\rm c}$, and the first measurement of $\Omega^{0}_{\rm c}$ baryons performed with the ALICE detector at midrapidity in pp collisions at $\sqrt{s}$ = 5.02 and 13 TeV. Recent measurements of charm-baryon production at midrapidity by the ALICE Collaboration in small systems show a baryon-over-meson ratio significantly higher than that in $e^+e^−$ collisions, suggesting that the fragmentation of charm is not universal across different collision systems. Thus, measurements of charm-baryon production are crucial to study the charm quark hadronisation in proton-proton collisions and its difference with respect to $e^+e^−$ collisions, which is also relevant for the description of heavy-flavour mesons. In fact, the production cross sections of open heavy-flavour hadrons are usually described within the factorisation approach as the convolution of the parton distribution functions of the incoming protons, the perturbative QCD partonic cross section, and the fragmentation functions which are typically parametrised from measurements in $e^+e^−$ collisions. In addition, the large measured baryon yields are an important contribution for an accurate measurement of the $\rm c\overline{c}$ production cross section at midrapidity in pp collisions at the LHC, which status and progresses are also presented. Furthermore, the new $\Lambda^{+}_{\rm c}/{\rm D^{0}}$ratio measured down to $p_{\rm T}$ = 0 in p-Pb collisions as well as the nuclear modification factor will be discussed. The measurement of charm baryons in p-nucleus collisions provides important information about Cold Nuclear Matter (CNM) effects. It also helps to understand how the possible presence of collective effects could modify production of heavy-flavour hadrons and the similarities observed among pp, p-nucleus and nucleus-nucleus systems. The results will be compared to models including CNM effects, as well as models assuming the formation of a quark-gluon plasma in p-Pb collisions.

Collaboration / Activity ALICE

Primary authors

ALICE Collaboration Luigi Dello Stritto (Università degli Studi di Salerno)

Presentation Materials