Conveners
Parallel Session T05: QGP in small and medium systems: I
- Tuomas Lappi
Parallel Session T05: QGP in small and medium systems: II
- Anton Andronic (Westfaelische Wilhelms-Universitaet Muenster (DE))
NA61/SHINE is a fixed target experiment at the CERN Super Proton Synchrotron. The main goals of the experiment are to discover the critical point of strongly interacting matter and to study the properties of the onset of deconfinement. In order to reach these goals, a study of hadron production properties is performed in nucleus-nucleus, proton-proton and proton-nucleus interactions as a...
The ultra-peripheral collisions (UPC) of relativistic heavy ion beams lead to a diverse set of photon-nucleus interactions.
The measurements of particles and their interaction produced in photo-nuclear reactions can shed light on the QCD dynamics of novel, extremely asymmetric colliding systems, with energies between those available at RHIC and the LHC.
Understanding the hadronic...
Over the last years, evidence of collective behavior has been observed in high-multiplicity collisions of small systems, however, its origin is not yet understood. In this talk, we will present the first measurement of ultra-long-range azimuthal angle correlations of identified particles in small collision systems by using forward detectors of ALICE, which allows the largest pseudorapidity...
The azimuthal anisotropies observed in small systems can originate from the final state response to the initial geometry as well as from initial momentum anisotropies. Recently it has been proposed that the correlation between the flow coefficient $v_{2}^2$ and the mean $p_\mathrm{T}$ carries information on the origin of flow in small collision systems by showing a characteristic sign change...
The experimental observations of anisotropic flows in proton-proton and
proton-nucleus collisions at RHIC and LHC energies has stimulated a big
interest in these small systems as a new study area for the formation and
evolution of the quark-gluon plasma. We investigate the effects of
non-equilibrium dynamics in such systems by comparing a microscopic
nonequilibrium transport approach, the...
Small collision systems exhibit features that are characteristic of collective flow, a hallmark of QGP formation. However, jet quenching in small systems has not yet been observed, and quantifying or setting limits on the magnitude of jet quenching in small systems is a key element in understanding the limits of QGP formation. In this talk we present a search for jet quenching effects in pp...
We present the measurement of two-particle correlations in hadronic $e^+e^-$ collisions data collected by the Belle detector at KEKB. The clean $e^+e^-$ collision system is conducive for the unambiguous investigation of the azimuthal anisotropy of final-state charged particles found in various heavy ion and proton-proton collisions. Following up on the first examination in $e^+e^-$...
The first measurement of $anti-k_{T}$ jets and two-particle angular correlations of charged particles emitted in high energy $e^+e^−$ annihilation is presented. The archived data at a center-of-mass energy of 91-209 GeV were collected with the ALEPH detector at LEP between 1992 and 2000.
At 91 GeV, no significant long-range correlation was observed in either the lab coordinate analysis or...
The creation of fluid-like quark-gluon plasma in small collision systems has been investigated via elliptical azimuthal anisotropy of emitted particles in these interactions. A novel search for QCD collective effects in hard probes is presented using high-$p_\mathrm{T}$ jets in 13 TeV pp collisions at CMS. Studies of short- and long-range azimuthal correlations inside a jet produced with very...
The suppression of the $J/\psi$ nuclear modification factor has been seen as a trademark signature of final state effects in large collision systems for decades. In small systems, deviations of the nuclear modification from unity had been attributed to cold nuclear matter effects until the observation of strong differential suppression of the $\psi(2S)$ state in $p/d$+A collisions, which...
Measurements of quarkonia and open-heavy flavor in hadronic collisions provide a unique testing ground for understanding quantum chromodynamics (QCD). Although recently there was significant progress, our understanding of hadronic collisions has been challenged by the observation in high-multiplicity proton-proton (pp) collisions of intriguing effects, such as collective phenomena.
The...
The observation of collectivity in small hadronic collisions raises the question whether the tiny droplet of quark gluon plasma can form in systems with size significantly smaller than nucleus-nucleus collisions. Dynamics and hadronization of heavy flavor quarks in small-system collisions provide a powerful tool to address the origin of observed collective phenomena because of their early...
The medium modification to particle spectra and the origin of collectivity in small collision systems are widely debated topics in our community.
To address these open questions we propose the study of particle production and collectivity for varying system sizes, presented in decreasing order (Au+Au $>$ Ru+Ru/Zr+Zr $>$ $^{3}$He+Au $>$ d+Au $>$ p+Au $>$ p+p $>$ $\gamma$+Au), available at...
