Some highlights on studies of strangeness and charm in heavy ion collisions by ALICE at LHC
Grigory Feofilov, Saint-Petersburg State University, RF,
(on behalf of the ALICE Collaboration)
The formation of a strongly interacting medium of deconfined quarks and gluons, known as the quark-gluon plasma (QGP), that occurs in the ultrarelativistic nuclear collisions at the LHC, can
be...
This work is devoted to the search for lambda hyperons and short-lived neutral kaons after collision of Xe beams with a CsI target at E = 3.9 AGeV at the BM@N experiment (JINR, Dubna). Simulation, reconstruction and filtering of 100,000 events were carried out. Peaks in the invariant mass distribution corresponding to lambda hyperons and kaons were obtained. Efficiency as a function of...
In the BM@N experiment at the Nuclotron accelerator, the production of $\pi^+$ and $K^+$ mesons in collisions of argon ions with an energy of 3.2 GeV with solid targets of C, Al, Cu, Sn, and Pb was studied. Yields are obtained in kinematic variables in terms of rapidity and transverse momentum. The estimation of the parameters of inverse slopes and multiplicities is performed. The results are...
NICA (Nuclotron-based heavy-Ion Collider fAcility) is a new flagship project at JINR (Dubna, Russia) aimed at the construction of a new accelerator complex for heavy ions and polarized particles [1]. Collisions of relativistic ions with energies up to 11 GeV (center-of-mass) will be studied with the MultiPurpose Detector MPD providing accurate precise tracking and reliable particle...
Obtaining quality physics results requires high-statistics
data with low background contamination. The task of maximizing
the signal as well as accurate estimation of combinatorial background
is especially important at the start-up of the experiment when the
amount of data is rather limited. The MPD experiment at the NICA collider
will have to deal with such issues in its first run.
...
Results on determination of the microscopic Hubble constant for pions and nucleons in Au+Au collisions at $\sqrt{s_{NN}} = 7.8$ GeV for a range of times and three impact parameters are presented and discussed. The data are simulated within PHSD model. A typically used method based on the fit of the velocity profile is considered in detail. Also a new method for determination of the Hubble...
Vortical structure of hot-dense matter in heavy ion collisions can be observed through global polarization of emitted particles.
Hyperon's weak decays provides opportunity to measure this phenomenon. Global polarization of $\Lambda$ hyperons was measured by the STAR experiment at RHIC for Au+Au collisions with $\sqrt{s_{NN}}$ = 3-200 GeV and at the LHC for Pb+Pb collisions with...
Using first-principle numerical simulations of the lattice SU(3) gauge theory, we calculate the isothermal moment of inertia of the rigidly rotating gluon plasma. We find that the moment of inertia unexpectedly takes a negative value below the "supervortical temperature" $T_s = 1.50(10) T_c$, vanishes at $T = T_s$, and becomes a positive quantity at higher temperatures. The negative moment of...
The coherent inelastic processes of the type $a \rightarrow b$, which
may take place in the interaction of hadrons and $\gamma$ quanta with
nuclei at very high energies ( the nucleus remains the same ), are
theoretically investigated. For taking into account the influence of
matter inside the nucleus, the optical model based on the concept of
refraction index is applied .
Analytical...
One of the main goals of the Relativistic Heavy-Ion Collider is to investigate the properties of quark-gluon plasma (QGP). Azimuthal anisotropy of hadrons produced in relativistic collisions is considered as a good tool to study QGP’s properties. It can be characterized using Fourier coefficients, where the second coefficient is the elliptic flow ($v_2$). Thus, hadron elliptic flow...
The study of the high-density equation of state (EOS) and the search for a possible phase transition in dense baryonic matter is the main goal of beam energy scan programs with relativistic heavy ions at energies $\sqrt{s_{NN}}$ = 2-5 GeV.
In this work, we discuss the layout of the MPD (NICA) experiment in the fixed target mode and the anticipated performance for differential anisotropic flow...
In this talk, we explore the potential of azimuthal flow as a tool for investigating color string fusion in proton-proton collisions.
Our approach is based on a detailed simulation of the longitudinal and transverse dynamics of strings leading to their subsequent fusion and decay [1,2]. Using model calculations, we demonstrate that the azimuthal anisotropy of the produced hadrons is...
In the relativistic heavy ion collisions at the beam energy of a few GeV the strongly interacting matter is created at high baryon densities and relatively low temperatures. Azimuthal anisotropy of the produced particles provides a valuable insight into the properties of this form of matter. In this work, we discuss the layout of the upgraded Baryonic Matter at Nuclotron (BM@N) experiment...
The study of nuclear multifragmentation in the relativistic energy region provides valuable insights into nuclear clusters and fragmentation characteristics. In this context, the Nuclear Track Emulsion (NTE) detector has been used in the BECQUEREL experiment to analyse the cluster structure of light nuclei, including radioactive ones [1]. NTE detector possess the significant advantages over...
The size and evolution of the matter created in a relativistic heavy-ion collision strongly depend on the collision's initial geometry, defined by centrality. Experimentally the centrality of collisions can be characterized by the measured multiplicities of the produced particles at midrapidity or by the energy measured in the forward rapidity region, which is sensitive to the spectator...
Glauber approach is widely used for describing multiparticle production in the interactions involving hadrons and nuclei in a wide energy range [1-2]. For the more detailed description of nuclear interaction features, this model is increasingly being used at the parton level [3-6], however, usually, the pp-interaction is given insufficient attention.
Before application of the model to...
In the framework of the model with string fusion we study the correlations between multiplicities in two separated rapidity windows in pp collisions at LHC energies and compare the results with the data obtained by ALICE collaborations at CERN.
The Monte Carlo modelling in the framework of a quark-gluon string model were implies. The string fusion effects were also taken into account by...
Data-driven techniques are frequently used in high energy physics to get reliable estimate of backgrounds from object misidentification. Here, an approach to the estimation of the background induced by the misidentification of a jet as a photon, in short jet → γ, is presented. It is based on real and fake efficiencies of real/fake photons to pass the tight identification criteria. Selected...
The analysis of ALEPH data on femtoscopic correlations of two lambda-hyperons in Z-boson decays yields a very small source radius of 0.11+/-0.03 fm if taking into account only the repulsion due to the Fermi-Dirac quantum statistics. Such a small source radius is counter-intuitive in the string picture of particle production due to a moderate string tension of ~1 GeV/fm. It is shown that the...
The study of the correlation between the multiplicity of charged particles and the average transverse momentum was carried out in proton-proton and nucleus-nucleus collisions from the SPS energy to the LHC energy [1]. Extending the experimental data from negative correlations at energies √s = 17–40 GeV to lower energies can lead to significant limitations for various theoretical models....
In strangeness nuclear physics, exotic hypernuclei with a proton or neutron excess are of particular interest now. Such systems relatively poorly explored in experiment can be produced in heavy ion collisions, particularly at NICA complex developed at JINR. Studies of exotic hypernuclei allow to improve the understanding of subtle features of the hyperon-nucleon and hyperon-nucleus...
One of the main goal of MPD/NICA scientific program is the precise measurement of light hadron spectra. In this report, the MPD performance to measure pt spectra of identified light hadrons at $\sqrt{s_{NN}} = 9.2$ GeV is presented as well as the performance to measure pt-integrated rapidity density dN/dy and full yields of light hadrons.
We have derived the exact and approximate transverse momentum distributions for the Bose-Einstein, Fermi-Dirac and Maxwell-Boltzmann statistics of particles in the Tsallis statistics with escort probabilities (the Tsallis-3 statistics). The Tsallis-3 statistics is considered by the scientific community to be the most correct. We have found that the classical phenomenological Tsallis...
The spectroscopy of charmonium-like mesons with masses above the 2_mD open charm threshold has been full of surprises and remains poorly understood. The currently most compelling theoretical descriptions of the mysterious XYZ mesons attribute them to hybrid structure with a tightly bound diquark or tetraquark core that strongly couples to S-wave DD\bar molecular like structures. The production...
We test the parametrizations of Fragmentation Functions (FFs) using data on semi-inclusive pion and kaon production in unpolarized pp and heavy-ion collisions at the STAR and NICA kinematics. The calculations are carried out in the next-to-leading order (NLO) of perturbative quantum chromodynamics (pQCD).
We show that at the c.m. energy 200 GeV both LSS-15 and DSEHS-14 FFs for pions and...
The technique of correlation femtoscopy helps one not only to estimate the geometric dimensions and lifetime of the particle emission region in nucleus-nucleus collisions, but also help to answer the question of whether the source has a boost-invariant spatiotemporal structure. This work is aimed to studying the femtoscopic parameters of identical-pion emission region in Au+Au collisions at...
Two-pion interferometry provides access to the spatial and temporal size, shape and evolution of their sources created in heavy ion collisions and hence offers strong constraints for the theoretical models.
In this work, we will report the measurement of correlation strength ($\lambda$) and femtoscopic radii ($R_{\mathrm{out}}$, $R_{\mathrm{side}}$, $R_{\mathrm{long}}$,...
Femtoscopy is a primary tool for measuring the spatiotemporal characteristics of small and short-lived systems created in particle or nuclear collisions with an accuracy of 1 fm. The possibility of such measurements is due to the effects of quantum statistics and final state interactions which create the momentum correlations of two or more particles at small relative momenta in their...
