ALICE

Das Feld der Hochenergie-Schwerionenforschung hat sich der Untersuchung des Quark-Gluon-Plasmas (QGP) gewidmet. Ein QGP ist ein sehr heißer und dichter Materiezustand, der kurz nach dem Urknall für einige Mikrosekunden das Universum füllte. [...]

The study of the production of nuclei and antinuclei in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. In this paper, the production of protons, deuterons and $^3$He and their charge conjugates at midrapidity is studied as a function of the charged-particle multiplicity in inelastic pp collisions at $\sqrt{s}=5.02$ TeV using the ALICE detector. [...]

The production of prompt D0, Ds+, and Λc+ hadrons, and their ratios, Ds+/D0 and Λc+/D0, are measured in proton–proton collisions at $\sqrt{s}$ = 13 TeV at midrapidity (|y|<0.5) with the ALICE detector at the LHC. The measurements are performed as a function of the charm-hadron transverse momentum (p$_T$) in intervals of charged-particle multiplicity, measured with two multiplicity estimators covering different pseudorapidity regions. [...]

Annihilation dynamics plays a fundamental role in the baryon--antibaryon ($B-\overline{B}$) interaction at low-energy and its strength and range are crucial in the assessment of possible baryon bound states. Experimental data on annihilation cross sections are available for the $p-\overline{p}$ system but not in the low relative momentum region. [...]

The measurement of the azimuthal-correlation function of prompt D mesons with charged particles in pp collisions at a centre-of-mass energy of $\sqrt{s} =$ 13 TeV with the ALICE detector is reported, considering D$^{0}$, D$^{+}$, and D$^{*+}$ mesons in the transverse-momentum interval $3 0.3$ GeV/$c$ and pseudorapidity $|\eta| < 0.8$ This measurement has an improved precision and provides an extended transverse-momentum coverage compared to previous ALICE measurements at lower energies. The study is also performed as a function of the charged-particle multiplicity, showing no modifications of the correlation function with multiplicity within uncertainties. [...]

The polarization of the $\Lambda$ and $\overline\Lambda$ hyperons along the beam ($z$) direction, $P_{\rm z}$, has been measured in Pb--Pb collisions at $\sqrt{s_{\rm NN}} =$ 5.02 TeV recorded with ALICE at the Large Hadron Collider (LHC). The largest contribution to $P_{\rm z}$ comes from elliptic flow induced vorticity and can be characterized by the second Fourier sine coefficient $P_{\rm z,\,{\rm s2}} = \langle{P_{\rm z}\sin(2\varphi - 2 \Psi_{\rm 2})}\rangle$, where $\varphi$ is the hyperon azimuthal emission angle, and $\Psi_{\rm 2}$ is the elliptic flow plane angle. [...]

The jet angularities are a class of jet substructure observables which characterize the angular and momentum distribution of particles within jets. These observables are sensitive to momentum scales ranging from perturbative hard scatterings to nonperturbative fragmentation into final-state hadrons. [...]

In particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD). These partons subsequently emit further partons in a process that can be described as a parton shower which culminates in the formation of detectable hadrons. [...]