ALICE

The future opportunities for high-density QCD studies with ion and proton beams at the LHC are presented. Four major scientific goals are identified: the characterisation of the macroscopic long wavelength Quark-Gluon Plasma (QGP) properties with unprecedented precision, the investigation of the microscopic parton dynamics underlying QGP properties, the development of a unified picture of particle production and QCD dynamics from small (pp) to large (nucleus--nucleus) systems, the exploration of parton densities in nuclei in a broad ($x$, $Q^2$) kinematic range and the search for the possible onset of parton saturation. [...]

We present the first measurements of femtoscopic correlations between the K$_S^0$ and K$^±$ particles in pp collisions at $\sqrt{s}$ = 7 TeV measured by the ALICE experiment. The observed femtoscopic correlations are consistent with final-state interactions proceeding solely via the a$_0$(980) resonance. [...]

The procedure for the energy calibration of the high granularity electromagnetic calorimeter PHOS of the ALICE experiment is presented. The methods used to perform the relative gain calibration, to evaluate the geometrical alignment and the corresponding correction of the absolute energy scale, to obtain the nonlinearity correction coefficients and finally, to calculate the time-dependent calibration corrections, are discussed and illustrated by the PHOS performance in proton-proton (pp) collisions at √s = 13 TeV. [...]

The production of the ρ(770)$^0$ meson has been measured at midrapidity (|y| < 0.5) in pp and centrality differential Pb-Pb collisions at $\sqrt{s_{\rm NN}}$= 2.76 TeV with the ALICE detector at the Large Hadron Collider. The particles have been reconstructed in the ρ(770)$^0$→π$^+$π$^−$ decay channel in the transverse-momentum ($p_{\rm T}$) range 0.5–11 GeV/c. [...]

Charged-particle spectra at midrapidity are measured in Pb–Pb collisions at the centre-of-mass energy per nucleon–nucleon pair $\sqrt{s_{\rm NN}}$= 5.02 TeV and presented in centrality classes ranging from most central (0–5%) to most peripheral (95–100%) collisions. Possible medium effects are quantified using the nuclear modification factor ($R_{\rm AA}$) by comparing the measured spectra with those from proton–proton collisions, scaled by the number of independent nucleon–nucleon collisions obtained from a Glauber model. [...]

In this letter, the production of deuterons and anti-deuterons in pp collisions at $\sqrt{s}$ = 7 TeV is studied as a function of the charged-particle multiplicity density at mid-rapidity with the ALICE detector at the LHC. Production yields are measured at mid-rapidity in five multiplicity classes and as a function of the deuteron transverse momentum ($p_{\rm T}$). [...]

Two-particle angular correlations were measured in pp collisions at $\sqrt{s} = 7$  TeV for pions, kaons, protons, and lambdas, for all particle/anti-particle combinations in the pair. Data for mesons exhibit an expected peak dominated by effects associated with mini-jets and are well reproduced by general purpose Monte Carlo generators. [...]

The production yield of prompt D mesons and their elliptic flow coefficient v$_2$ were measured with the Event-Shape Engineering (ESE) technique applied to mid-central (10–30% and 30–50% centrality classes) Pb-Pb collisions at the centre-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}}$ = 5.02 TeV, with the ALICE detector at the LHC. The ESE technique allows the classification of events, belonging to the same centrality, according to the azimuthal anisotropy of soft particle production in the collision. [...]

In this Letter, the ALICE Collaboration presents the first measurements of the charged-particle multiplicity density, dN$_{\rm ch}$/dη , and total charged-particle multiplicity, N$_{\rm ch}^{\rm tot}$, in Xe–Xe collisions at a centre-of-mass energy per nucleon–nucleon pair of $\sqrt{s_{\rm NN}}$ = 5.44TeV . The measurements are performed as a function of collision centrality over a wide pseudorapidity range of −3.5 < η < 5 . [...]