scholarly journals Correlation femtoscopy at NICA energies

2019 ◽  
Vol 222 ◽  
pp. 02004
Author(s):  
Konstantin Mikhaylov ◽  
Pavel Batyuk ◽  
Olga Kodolova ◽  
Lyudmila Malinina ◽  
Grigory Nigmatkulov ◽  
...  
Keyword(s):  
Particle Production ◽  
Final State ◽  
High Energies ◽  
Physics Program ◽  
First Order Phase Transition ◽  
Low Energies ◽  
Theoretical Predictions ◽  
Final State Interactions ◽  
First Order Phase ◽  
Beam Energy Scan

The space-time characteristics of particle production are measured by the correlation femtoscopy with use of quantum statistics (QS) and final state interactions (FSI) effects. Femtoscopy at lower energy was a key of importance at AGS, SPS and in the Beam Energy Scan (BES) physics program at RHIC. Using femtoscopy observables we investigate possibilities to observe a difference from the first-order phase transition expected, according to some theoretical predictions, at low energies and the cross over one, to be occurred at high energies. The hybrid model vHLLE+UrQM is used as a baseline for this study. The possibilities to use kaon femtoscopy complementary to the usually used pion one are discussed.

scholarly journals Three-fluid Hydrodynamics-based Event Simulator Extended by UrQMD final State interactions (THESEUS) for FAIR-NICA-SPSBES/RHIC energies

2018 ◽  
Vol 182 ◽  
pp. 02056 ◽  
Author(s):  
P. Batyuk ◽  
D. Blaschke ◽  
M. Bleicher ◽  
Yu.B. Ivanov ◽  
Iu. Karpenko ◽  
...  
Keyword(s):  
Equations Of State ◽  
Transport Model ◽  
Event Generator ◽  
Final State ◽  
First Order Phase Transition ◽  
First Results ◽  
Rapidity Distributions ◽  
Final State Interactions ◽  
Model Equations ◽  
Fluid Hydrodynamics

We present a new event generator based on the three-fluid hydrodynamics (3FH) approach, followed by a particlization at the hydrodynamic decoupling surface and a subsequent UrQMD afterburner stage based on the microscopic UrQMD transport model that accounts for hadronic final state interactions. First results for Au+Au collisions are presented. The following topics are addressed: the directed flow, transversemass spectra, as well as rapidity distributions of protons, pions and kaons for two model equations of state, one with a first-order phase transition, the other with a crossover transition. Preliminary results on the femtoscopy are also discussed.We analyze the accuracy of reproduction of the 3FH results by the new event generator and the effect of the subsequent UrQMD afterburner stage.

STUDY OF MESON PRODUCTION IN NUCLEI NEAR THRESHOLD

2009 ◽  
Vol 18 (05n06) ◽  
pp. 1271-1281 ◽  
Author(s):  
B. K. JAIN ◽  
N. J. UPADHYAY ◽  
K. P. KHEMCHANDANI ◽  
N. G. KELKAR
Keyword(s):  
Cross Sections ◽  
Final State Interaction ◽  
Scattering Length ◽  
Meson Production ◽  
Final State ◽  
Total Cross Sections ◽  
Low Energies ◽  
Final State Interactions ◽  
T Matrix ◽  
Near Threshold

We present a study of the η production at low energies in pd collision with 3He and pd nuclear systems in the final state. The η production mechanism is described by a two-step model and the final state interactions are included fully. The η - d and η - 3He final state interactions are incorporated through the solution of the Lippmann Schwinger equation for a half off-shell η - AT-matrix. For η - d this t -matrix is written in a factorized form, with an off-shell form factor multiplying an on-shell part having the scattering length representation. The p - d final state interaction is included by multiplying the production matrix element by the inverse of the Jost function which includes the strong as well as the Coulomb interaction. The total cross sections are found to be strongly affected by both the η - d and the p - d final state interactions. The η - 3HeT-matrix is obtained in the Finite Rank Approximation (FRA) by solving few-body equations. The calculated total cross sections are in good accord with the available experimental data. Through the time delay method of Wigner, we also explore the possibility of the existence of quasi-bound η-3 He mesic states in this η - 3He T -matrix. We find that the T -matrix which reproduces the low energy pd → 3He η data implies a quasi-bound eta state near threshold. This is in accord with experimental indications.

scholarly journals The horn, kink and step, dale: from few GeV to few TeV

Open Physics ◽  
2012 ◽  
Vol 10 (6) ◽  
Author(s):  
Anar Rustamov
Keyword(s):  
Early Stage ◽  
Heavy Ion ◽  
Strong Interactions ◽  
Asymptotic Freedom ◽  
High Energies ◽  
Ion Collisions ◽  
First Order Phase Transition ◽  
Onset Of Deconfinement ◽  
First Order Phase ◽  
Na49 Experiment

AbstractRich experimental data have been collected in heavy-ion collisions at high energies to study the properties of strongly interacting matter. As the theory of strong interactions, QCD, predicts asymptotic freedom, the created matter at sufficiently high temperature and density will be dominated by a state of quasi-free quarks and gluons referred to as the Quark-Qluon Plasma (QGP). Experimental signals for the onset of the QGP creation (the onset of the deconfinement) have been predicted within the statistical model for the early stage of nucleus-nucleus collisions. In this model the existence of two different phases is assumed: confined mater and the QGP, as well as a first order phase transition between them. Until recently, these predictions were confirmed only by the NA49 experiment at the CERN SPS. In this report recent results from STAR at RHIC/BNL and from ALICE at LHC/CERN, related to the onset of deconfinement, will be compared to published results from NA49.

scholarly journals Recent flow and femtoscopy results from STAR

2019 ◽  
Vol 204 ◽  
pp. 03010 ◽  
Author(s):  
Grigory Nigmatkulov
Keyword(s):  
Quark Gluon Plasma ◽  
Collision Energy ◽  
Gluon Plasma ◽  
Azimuthal Anisotropy ◽  
Transverse Mass ◽  
First Order ◽  
Turn On ◽  
High Energies ◽  
First Order Phase Transition ◽  
First Order Phase

Azimuthal anisotropy and femtoscopic measurements provide information about collectivity and dynamics of the created medium. Data from the BES enables STAR to search for the turn-on/off signatures of the Quark-Gluon Plasma (QGP), for the first-order phase transition, and to constrain various models. In midcentral collisions, the proton and net-proton slope parameter (dυ1=dy|y=0) shows a minimum between $$\sqrt {{s_{NN}}} = 11.5$$ and 19.6 GeV. The pion and kaon femtoscopic radii are also measured as a function of transverse mass (mT ), centrality and collision energy, and showing that the system at high energies lives longer.

scholarly journals Coulomb Final State Interaction in Heavy Ion Collisions for Lévy Sources

Universe ◽  
2019 ◽  
Vol 5 (6) ◽  
pp. 133 ◽  
Author(s):  
Máté Csanád ◽  
Sándor Lökös ◽  
Márton Nagy
Keyword(s):  
Coulomb Interaction ◽  
Heavy Ion Collisions ◽  
Particle Production ◽  
Final State Interaction ◽  
Heavy Ion ◽  
High Energy ◽  
State Interaction ◽  
Final State ◽  
Ion Collisions ◽  
Final State Interactions

Investigation of momentum space correlations of particles produced in high energy reactions requires taking final state interactions into account, a crucial point of any such analysis. Coulomb interaction between charged particles is the most important such effect. In small systems like those created in e + e - - or p + p collisions, the so-called Gamow factor (valid for a point-like particle source) gives an acceptable description of the Coulomb interaction. However, in larger systems such as central or mid-central heavy ion collisions, more involved approaches are needed. In this paper we investigate the Coulomb final state interaction for Lévy-type source functions that were recently shown to be of much interest for a refined description of the space-time picture of particle production in heavy-ion collisions.

Tactoidal Granules in Concentrated Actin Gels: A Solidlike State of Protein Filaments

1997 ◽  
Vol 489 ◽  
Author(s):  
Jay. X. Tang ◽  
Rudolf Oldenbourg ◽  
Philip G. Allen ◽  
Paul A. Janmey
Keyword(s):  
Orientational Order ◽  
Elastic Response ◽  
Excluded Volume Effects ◽  
First Order Phase Transition ◽  
Contrast Microscopy ◽  
Theoretical Predictions ◽  
Molecular Forces ◽  
First Order Phase ◽  
Thermodynamic Phase

AbstractWe report here the first observation and microscopic characterization of tactoidal granules of actin in concentrated gels of actin filaments (F-actin). Phase contrast microscopy shows these stable tactoids of densely packed F-actin to be of various sizes on the order of 10 μm. The background gel of F-actin is optically birefringent, indicating orientational order of the filaments consistent with theoretical predictions. In contrast, no birefringence is detected through the tactoids, suggesting very distinct yet undetermined packing of the filaments inside. The tactoids demonstrate elastic response upon micromanipulation. The microscopic segregation of F-actin into two states of different protein concentrations is consistent with a first order phase transition between a nematic gel of lower concentration on the order of ten mg/nl and a highly packed, possibly columnar state of protein filaments. In addition to the excluded volume effects which are known to drive thermodynamic phase transitions as a function of particle concentration, additional molecular forces must also play important roles since the formation was found to be irreversible upon dilution.

GENERALIZATION ERROR AND DYNAMICAL EFFECTS IN A TWO-DIMENSIONAL PATCHES DETECTOR

1991 ◽  
Vol 02 (01n02) ◽  
pp. 115-124 ◽  
Author(s):  
I. Kocher ◽  
R. Monasson
Keyword(s):  
Phase Transition ◽  
Monte Carlo ◽  
Two Dimensional ◽  
Generalization Error ◽  
Training Set ◽  
Error Curve ◽  
First Order ◽  
First Order Phase Transition ◽  
Theoretical Predictions ◽  
First Order Phase

We study the supervised learning of a two-dimensional patches detector. We compute the generalization error of the network with the annealed approximation; a first-order phase transition appears at all temperatures on the generalization error curve as a function of the size of the training set. We show that the system is subject to dynamical effects: the earlier story of presentation of the patterns to the system can be relevant, and a hysteresis appears on the generalization error curve. We show Monte Carlo simulations which agree with the theoretical predictions.

scholarly journals REVIEW OF RECENT RESULTS FROM THE RHIC BEAM ENERGY SCAN

2013 ◽  
Vol 28 (36) ◽  
pp. 1330033 ◽  
Author(s):  
LOKESH KUMAR
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Beam Energy ◽  
Center Of Mass ◽  
Baryon Density ◽  
Qcd Phase Diagram ◽  
First Order Phase Transition ◽  
First Order Phase ◽  
Beam Energy Scan ◽  
First Time

We review recent results from the RHIC beam energy scan (BES) program, aimed to study the Quantum Chromodynamics (QCD) phase diagram. The main goals are to search for the possible phase boundary, softening of equation of state or first order phase transition, and possible critical point. Phase-I of the BES program has recently concluded with data collection for Au+Au collisions at center-of-mass energies [Formula: see text] of 7.7, 11.5, 19.6, 27 and 39 GeV. Several interesting results are observed for these lower energies where the net-baryon density is high at the mid-rapidity. These results indicate that the matter formed at lower energies (7.7 and 11.5 GeV) is hadron dominated and might not have undergone a phase transition. In addition, a centrality dependence of freeze-out parameters is observed for the first time at lower energies, slope of directed flow for (net)-protons measured versus rapidity shows an interesting behavior at lower energies, and higher moments of net-proton show deviation from Skellam expectations at lower energies. An outlook for the future BES Phase-II program is presented and efforts for the detailed study of QCD phase diagram are discussed.

scholarly journals Baryogenesis via relativistic bubble walls

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Aleksandr Azatov ◽  
Miguel Vanvlasselaer ◽  
Wen Yin
Keyword(s):  
Particle Production ◽  
Heavy Particle ◽  
Baryon Number ◽  
Baryon Asymmetry ◽  
Relativistic Velocity ◽  
Production Mechanism ◽  
Bubble Wall ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

Abstract We present a novel mechanism which leads to the baryon asymmetry generation during the strong first order phase transition. If the bubble wall propagates with ultra-relativistic velocity, it has been shown [1] that it can produce states much heavier than the scale of the transition and that those states are then out of equilibrium. In this paper, we show that this production mechanism can also induce CP-violation at one-loop level. We calculate those CP violating effects during the heavy particle production and show, that combined with baryon number violating interactions, those can lead to successful baryogenesis. Two models based on this mechanism are constructed and their phenomenology is discussed. Stochastic gravitational wave signals turn out to be generic signatures of this type of models.

Sign in / Sign up

Export Citation Format

Share Document