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Sona Pochybova

Publications and source records attributed to Sona Pochybova.

5 recordsLinked to original sources

Overview of ALICE results on azimuthal correlations using neutral- and heavy-meson triggers

The ALICE detector is dedicated to studying the properties of hot and dense matter created in heavy-ion collisions. Among the probes used to investigate these properties are high-momentum particles, which originate in hard-scatterings occurring before the fireball creation. The fragments of hard scatterings interact with the hot and dense matter and via this interaction their spectra and azimuthal distributions are modified. This is probed by the measurement of the nuclear modification factor, where the $p_{\mathrm{T}}$ spectra obtained in Pb-Pb collisions are compared to a pp baseline. A strong suppression of charged hadrons as well as neutral- and heavy-flavor mesons was observed at $p_{\mathrm{T}} > 4$ GeV/$c$. Azimuthal correlations, using high-momentum ($p_{\mathrm{T}} > 4$ GeV/$c$) hadrons as triggers, can provide further insight into how the presence of the medium modifies the final kinematic distributions of the particles. Comparison with theoretical models can be used to test their predictions about the properties of the medium. We give an overview of ALICE azimuthal-correlation measurements of neutral- and heavy-flavor mesons with charged hadrons in pp collisions at $\sqrt{s}=7$ TeV and Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}=2.76$ TeV. We also present a measurement of the $π^{0}$ correlation with jets in pp collisions at $\sqrt{s}=7$ TeV.

hep-ex↗

On particle production in jets with quark-like and gluon-like fragmentation

We study the $p/π$ ratio in jets produced in simulated proton-proton collisions at $\sqrt{s_{NN}}=7~\mathrm{TeV}$ using Pythia $6.4$ Monte-Carlo generator. We compare the $p/π$ ratio in the selected quark-like and gluon-like jets to a reference samples of quark- and gluon-jets tagged at Monte-Carlo level. We observe that the contamination in the selected jets significantly influences the observed ratios. This suggests, that the origin of the jet fixes the value of the $p/π$ ratio within the model that we use.

hep-ph↗

Experimental treatment of Quark and Gluon Jets

The separate study of quark and gluon jets is vital for the interpretation of multiple variables behaviour observed in both high-energy hadron and heavy-ion collisions in the present and future experiments. We propose a set of jet-energy dependent cuts to be used to distinguish between quark and gluon jets experimentally based on a Monte-Carlo study of their properties. Further, we introduce the possibility to calibrate these cuts via gamma-jet and multi-jet events, which represent clean production channels for quark and gluon jets, respectively. The calibration can happen on real data and thus, reduces the dependence of the method performance on Monte-Carlo model predictions.

hep-ex↗

Study of particle production from quark and gluon jets in proton-proton collisions

We investigate whether and how different fragmentation properties of quarks and gluons affect identified particle spectra. We present a systematic study of $π$, $K$ and $p$ production in minimum bias (inelastic, non-diffractive), two- and three-jet events at RHIC, Tevatron and LHC energies. Through the study of two- and three-jet events and various jet-production channels we can directly access the fragmentation properties of quark and gluon jets. We present MC estimate for the contribution of quark and gluon jets to individual particle species spectra, that can be compared to experimental results and test our current knowledge of the physics behind particle production inside jets.

hep-ex↗

Topological study of three-jet events in ALICE

The ALICE experiment at LHC is dedicated to study matter formed in heavy-ion collisions, but also has a strong physics program for $pp$ collisions. In these collisions, protons will collide at energies never reached before under laboratory conditions. At the high energies, ALICE will enable us to study jet physics in detail, especially the production of multiple jet events, setting the baseline for heavy-ion. Three-jet events allow us to examine the properties of quark and gluon jets, providing a suitable tool for testing QCD experimentally. We discuss the selection method and topology of three-jet events in ALICE. The analysis was performed on two PYTHIA data sets, both involving $pp$ collisions at $\sqrt{s} = 14$ TeV with enhanced jet production. The results from the dedicated jet MC production are discussed and compared to previous studies at CDF and DØ. We investigate the possibilities to determine gluon jet candidates.

hep-ex↗