Thu·Dec 28, 2017Thursday·December 28, 2017

1. 01*

   ${\Lambda }_{\mathrm{c}}^{+}$ production in pp collisions at $\sqrt{s}=7$ TeV and in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   The $p_{\mathrm{T}}$-differential production cross section of prompt ${\Lambda }_{\mathrm{c}}^{+}$ charmed baryons was measured with the ALICE detector at the Large Hadron Collider (LHC) in pp collisions at $\sqrt{s}=7$ TeV and in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV at midrapidity. The ${\Lambda }_{\mathrm{c}}^{+}$ and ${\overline{\Lambda }}_{\mathrm{c}}^{-}$ were reconstructed in the hadronic decay modes ${\Lambda }_{\mathrm{c}}^{+}\to \mathrm{p}{\mathrm{K}}^{-}{\pi }^{+}$, ${\Lambda }_{\mathrm{c}}^{+}\to \mathrm{p}{\mathrm{K}}_{\mathrm{S}}^0$ and in the semileptonic channel ${\Lambda }_{\mathrm{c}}^{+}\to {\mathrm{e}}^{+}{\nu }_{\mathrm{e}}\Lambda$ (and charge conjugates). The measured values of the ${\Lambda }_{\mathrm{c}}^{+}/{\mathrm{D}}_0$ ratio, which is sensitive to the c-quark hadronisation mechanism, and in particular to the production of baryons, are presented and are larger than those measured previously in different colliding systems, centre-of-mass energies, rapidity and $p_{\mathrm{T}}$ intervals, where the ${\Lambda }_{\mathrm{c}}^{+}$ production process may differ. The results are compared with the expectations obtained from perturbative Quantum Chromodynamics calculations and Monte Carlo event generators. Neither perturbative QCD calculations nor Monte Carlo models reproduce the data, indicating that the fragmentation of heavy-flavour baryons is not well understood. The first measurement at the LHC of the ${\Lambda }_{\mathrm{c}}^{+}$ nuclear modification factor, $R_{\mathrm{pPb}}$, is also presented. The $R_{\mathrm{pPb}}$ is found to be consistent with unity and with that of D mesons within the uncertainties, and consistent with a theoretical calculation that includes cold nuclear matter effects and a calculation that includes charm quark interactions with a deconfined medium.

   nucl-exhep-exJHEP(2018)·167 citations
2. 02*

   Performance of the MPD experiment for the anisotropic flow measurement

   P. Parfenov🇷🇺 · I. Selyuzhenkov🇷🇺 · A. Taranenko🇷🇺 · A. Truttse🇷🇺

   The main goal of the future MPD experiment at NICA is to explore the QCD phase diagram in the region of highly compressed and hot baryonic matter in the energy range corresponding to the highest chemical potential. Properties of such dense matter can be studied using azimuthal anisotropy which is categorized by the Fourier coefficients of the azimuthal distribution decomposition. Performance of the detector response based on simulations with realistic reconstruction procedure is presented for centrality determination, reaction plane estimation, directed and elliptic flow coefficients.

   ↳ hep-exnucl-exKnE Energ.Phys.(2018)·2 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.