Quark Matter 2018

Measurement of Ds+/D+ as a function of transverse momentum and charged-particle multiplicity in pp, p-Pb and Pb-Pb collisions with ALICE

15 May 2018, 17:00

2h 40m

First floor and third floor (Palazzo del Casinò)

Poster Open heavy flavour Poster Session

Speaker

Fabrizio Grosa (Politecnico di Torino (IT))

Description

Heavy quarks (charm or beauty) are powerful probes to study and characterise the properties of the deconfined medium created in high-energy heavy-ion collisions, the Quark-Gluon Plasma (QGP). Because of their large masses, heavy quarks are produced in initial hard-scattering processes, and they subsequently experience the whole system evolution, interacting with the medium constituents. The observation of a large suppression of the heavy-flavour hadron yields at intermediate/high transverse momentum ($p_{\mathrm{T}}$) in central Pb-Pb collisions with respect to those in pp collisions provides a strong evidence of the in-medium parton energy loss. Moreover, the measurement of heavy-flavour hadrons with strange-quark content (i.e. ${\mathrm{D}}_{\mathrm{s}}^{+}$ mesons) can give insight into the heavy-quark hadronisation mechanism. If a fraction of charm quarks hadronises via coalescence, the relative abundance of ${\mathrm{D}}_{\mathrm{s}}^{+}$ with respect to non-strange D mesons is expected to be larger in heavy-ion collisions compared to pp collisions, due to the enhanced production of strange quarks in the QGP. Furthermore, an enhanced production of strange and multi-strange hadrons was recently observed in high-multiplicity pp and p-Pb collisions. For these reasons, the measurement of the production of ${\mathrm{D}}_{\mathrm{s}}^{+}$ mesons compared to that of non-strange D mesons as a function of the charged-particle multiplicity ($\mathrm{d}{N}_{\mathrm{c}\mathrm{h}}/\mathrm{d}\eta$) is interesting to study a possible enhancement of particles with strange-quark content in pp and p-Pb collisions in the heavy-quark sector, similar to the one observed for light hadrons.

In this poster, the measurement of ${\mathrm{D}}_{\mathrm{s}}^{+}/{\mathrm{D}}^{+}$ yield ratios as a function of $p_{\mathrm{T}}$ in pp collisions at $\sqrt{s}=7\mathrm{T}\mathrm{e}\mathrm{V}$ and Pb-Pb collisions at $\sqrt{s_{\mathrm{N}\mathrm{N}}}=5.02\mathrm{T}\mathrm{e}\mathrm{V}$, and as a function of $\mathrm{d}{N}_{\mathrm{c}\mathrm{h}}/\mathrm{d}\eta$ in p-Pb and Pb-Pb collisions at $\sqrt{s_{\mathrm{N}\mathrm{N}}}=5.02\mathrm{T}\mathrm{e}\mathrm{V}$, will be presented.

Presentation materials

DsOverDplus_pp_pPb_PbPb_QM2018_Grosa_final.pdf