Measurement of azimuthal correlations between D mesons and charged hadrons with ALICE at the LHC

The comparison of angular correlations between charmed mesons and charged hadrons produced in pp, p-Pb and Pb-Pb collisions can give insight into the mechanisms through which charm quarks lose energy in a QGP medium, produced in ultra-relativistic heavy-ion collisions, and can help to recognize possible modifications of their hadronization induced by the presence of the QGP. The analysis of pp and p-Pb data and the comparison with predictions from pQCD calculations, besides constituting the necessary reference for interpreting Pb-Pb data, can provide relevant information on charm production and fragmentation processes. In addition, possible differences between the results from pp and p-Pb collisions can give information on the presence of cold nuclear matter effects, affecting the charm production and hadronization in the latter collision system. A study of azimuthal correlations between D$^0$, D$^+$, and D$^{*+}$ mesons and charged hadrons in pp collisions at $\sqrt{s}$ = 7 TeV and p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV are presented. D mesons were reconstructed from their hadronic decays at central rapidity in the transverse-momentum range $3 \leq p_{\rm T}^{\rm D} \leq 16$ GeV/$c$ and were correlated to charged particles reconstructed in the pseudorapidity range $|\eta| < 0.8$. Perspectives for the measurement in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV will also be presented.Comment: 5 pages, 4 figures, Proceedings of the QCD@Work 2014 conference, 16-19 June 2014, Giovinazzo (Italy

Heavy-flavor correlations and multiplicity dependence in pp and p--Pb collisions with ALICE

The production of heavy quarks in pp collisions at the LHC energies provides a reliable test of perturbative QCD calculations. Comparisons of pp and \pPb measurements of their hadronization products allow us to investigate how cold nuclear matter effects affect the heavy-quark production. We present ALICE measurements of azimuthal correlations of prompt D mesons with charged hadrons in pp collisions at \s = 7 TeV and \pPb collisions at \sNN = 5.02 TeV. We also show the per-event D-meson yields as a function of the charged-particle multiplicity in pp collisions at \s = 7 TeV.Comment: Proceedings of Quark Matter 2015 conferenc

D meson-hadron angular correlations in pp and p-Pb collisions with ALICE at the LHC

The comparison of angular correlations between charmed mesons and charged hadrons produced in pp, p-Pb and Pb-Pb collisions can give insight into charm quark energy loss mechanisms in hot nuclear medium formed in heavy-ion collisions and can help to spot possible modifications of charm quark hadronization induced by the presence of the medium. The analysis of pp and p-Pb data and the comparison with predictions from pQCD calculations, besides constituting the necessary baseline for the interpretation of Pb-Pb results, can provide relevant information on charm production and fragmentation processes. We present a study of azimuthal correlations between D$^0$ and D$^{\ast +}$ mesons and charged hadrons measured by the ALICE experiment in pp collisions at $\sqrt{s} = 7$ TeV and p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV. D mesons were reconstructed from their hadronic decays at central rapidity and in the transverse momentum range $2 < p_{_{\rm T}} < 16$ GeV/$c$, and they were correlated to charged hadrons reconstructed in the pseudorapidity range $|\eta| < 0.8$.Comment: 4 pages, 4 figures. Proceedings of the Strangeness in Quark Matter Conference (SQM 2013), 22nd - 27th July 2013, published by the Open Access Journal of Physics: Conference Series (JPCS), in the IOP conference serie

Heavy-flavour production in pp collisions and correlations in pp and p-Pb collisions measured with ALICE at the LHC

Thanks to its excellent tracking and particle identification performance, the ALICE detector is capable of measuring D mesons at central rapidity via their hadronic decay channels down to very low transverse momentum. We show an extension of the prompt ${\rm D}^0$ $p_{\rm T}$-differential cross section measurement down to zero transverse momentum, which allows us to determine the $p_{\rm T}$-integrated charm production cross section at central rapidity in pp collisions at $\sqrt{s}$ = 7 TeV. We also present measurements of azimuthal correlations of prompt ${\rm D}^0$, ${\rm D}^+$ and ${\rm D}^{*+}$ mesons with charged hadrons in pp collisions at $\sqrt{s}$ = 7 TeV and p-Pb collisions at $\sqrt{s_{\scriptscriptstyle \rm NN}}$ = 5.02 TeV and compare the results with expectations from models.Comment: Proceedings for Strangeness in Quark Matter 2016 conference - 4 pages, 3 figure

Measurement of cross section for D0 direct production from the Kπππ decay channel in p-p collisions at √s = 7TeV with ALICE

The production of the D0 meson in pp collisions at √s = 7TeV through its hadronic decay in Kπππ, using the ALICE detector, is measured. By applying a series of topological cuts and PID selections, signal peaks in the invariant mass distribution M(Kπππ) have been found in different pT bins, ranging from 4.5 to 25 GeV/c. After performing corrections for efficiency, acceptance and feed-down from beauty contribution, differential direct production yield and cross section can be computed and compared to pQCD theoretical predictions which show a good agreement for the shape of the pT-differential cross section

INFN What Next: Ultra-relativistic Heavy-Ion Collisions

This document was prepared by the community that is active in Italy, within INFN (Istituto Nazionale di Fisica Nucleare), in the field of ultra-relativistic heavy-ion collisions. The experimental study of the phase diagram of strongly-interacting matter and of the Quark-Gluon Plasma (QGP) deconfined state will proceed, in the next 10-15 years, along two directions: the high-energy regime at RHIC and at the LHC, and the low-energy regime at FAIR, NICA, SPS and RHIC. The Italian community is strongly involved in the present and future programme of the ALICE experiment, the upgrade of which will open, in the 2020s, a new phase of high-precision characterisation of the QGP properties at the LHC. As a complement of this main activity, there is a growing interest in a possible future experiment at the SPS, which would target the search for the onset of deconfinement using dimuon measurements. On a longer timescale, the community looks with interest at the ongoing studies and discussions on a possible fixed-target programme using the LHC ion beams and on the Future Circular Collider.Comment: 99 pages, 56 figure

Study of azimuthal correlations between D mesons and charged particles with the ALICE experiment

A study of azimuthal correlations between D$^0$, D$^+$, and D$^{*+}$ and charged particles in pp collisions at $\sqrt{s}$ = 7 TeV and p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV is presented. D mesons were reconstructed from their hadronic decays at central rapidity ($|y| < 0.5$) in the transverse momentum range $3 \leq p_{\rm T}^{\rm D} \leq 16$ GeV/$c$ and they were correlated with charged particles reconstructed in the pseudorapidity range $|\eta| < 0.8$. Perspectives for the measurement in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.5 TeV after the ALICE upgrade are presented as well.Comment: 4 pages, 3 figures (5 panels), Proceedings for the Hot Quarks 2014 Workshop (Las Negras, Spain, 21-28/09/2014

Effective Rheology of Bubbles Moving in a Capillary Tube

We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 $< p_{\rm{T}, assoc} < p_{\rm{T}, trig} <$ 5.0 GeV/$c$ is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range $|\eta|<0.9$. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161