scholarly journals Improved intermittency analysis of proton density fluctuations in NA49 ion collisions at 158 AGeV

2014 ◽  
Vol 71 ◽  
pp. 00035 ◽  
Author(s):  
Nikolaos G. Antoniou ◽  
Nikolaos N. Davis ◽  
Fotios K. Diakonos ◽  
Keyword(s):  
Density Fluctuations ◽  
Proton Density ◽  
Ion Collisions ◽  
Intermittency Analysis

Search for critical fluctuations of the proton density in central A+A collisions at maximum SPS energy

Open Physics ◽  
2012 ◽  
Vol 10 (6) ◽  
Author(s):  
Nikolaos Antoniou ◽  
Nikos Davis ◽  
Fotis Diakonos
Keyword(s):  
Transverse Momentum ◽  
Invariant Mass ◽  
Power Law ◽  
Momentum Space ◽  
Density Fluctuations ◽  
Proton Density ◽  
Production Threshold ◽  
Critical Fluctuations ◽  
Intermittency Analysis

AbstractWe performed an intermittency analysis of the proton density fluctuations in transverse momentum space for the collisions Si+A (A=Al,Si,P) and C+A (A=C,N) at maximum SPS energy $\sqrt {s_{NN} } $ ≈ 17 GeV). In our analysis we used exclusively proton tracks in the midrapidity region (|y CM| ≤ 0.75). For the Si+A system we find signature of power-law distributed density fluctuations quantified by the intermittency index ϕ 2 which approaches in size the predictions of critical QCD [Phys. Rev. Lett. 97, 032002 (2006)]. This result supports further the recent findings of power-law fluctuations in the density of (π +, π −) pairs with invariant mass close to their production threshold for the Si+Si at the same energy, reported in [Phys. Rev. C 81, 064907 (2010)].

scholarly journals Model comparison for initial density fluctuations in high-energy heavy-ion collisions

2020 ◽  
Vol 102 (5) ◽  
Author(s):  
Stefan Floerchinger ◽  
Eduardo Grossi ◽  
Kianusch Vahid Yousefnia
Keyword(s):  
Heavy Ion Collisions ◽  
Model Comparison ◽  
Initial Density ◽  
Heavy Ion ◽  
High Energy ◽  
Density Fluctuations ◽  
Ion Collisions

Mutual Iinformation exchange in solar wind density fluctuations

2020 ◽  
Author(s):  
Luca Sorriso-Valvo ◽  
Francesco Carbone ◽  
Daniele Telloni
Keyword(s):  
Solar Wind ◽  
Mutual Information ◽  
Information Flow ◽  
Information Exchange ◽  
Turbulent Energy ◽  
Density Fluctuations ◽  
Slow Solar Wind ◽  
Proton Density ◽  
Mode Decomposition ◽  
Turbulent Cascade

<p>The fluctuations of proton density in the slow solar wind are analyzed by means of joint Empirical Mode Decomposition (EMD) and Mutual Information (MI) analysis. The analysis reveal that, within the turbulent inertial range, the EMD modes associated with nearby scales have their phases correlated, as shown by the large information exchange. This is a qunatitative measure of the information flow occurring in the turbulent cascade. On the other hand, at scales smaller than the ion gyroscale, the information flow is lost, and the mutual information is low, suggesting that in the kinetic range the nonlinear interacions are no longer sustaining a turbulent energy cascade.</p>

What can Hall-MHD simulations tell us about the transition region in the solar wind proton density spectrum?

2020 ◽  
Author(s):  
Victor Montagud-Camps ◽  
František Němec ◽  
Jana Šafránková ◽  
Zdeněk Němeček ◽  
Roland Grappin ◽  
...  
Keyword(s):  
Solar Wind ◽  
Transition Region ◽  
Spectral Index ◽  
Density Fluctuations ◽  
Power Density Spectrum ◽  
Proton Density ◽  
Density Spectrum ◽  
Significant Difference ◽  
Field Fluctuations ◽  
Hall Mhd

<p>Similarly to the power density spectrum of magnetic field fluctuations in the solar wind, the spectrum of density fluctuations also shows multiple spectral slopes. Both of them present a spectral index varying between –3/2 and –5/3 in the inertial range and close to –2.8 between the proton and electron gyrofrequencies.</p><p>Despite these similarities, the spectrum of density fluctuations has a significant difference with respect to the magnetic and velocity fluctuations spectra: it shows a transition region between the inertial and the kinetic ranges with spectral index typically around –1.</p><p>We have combined the results of compressible Hall-MHD numerical simulations and measurements of the BMSW instrument onboard Spektr-R satellite to study the possible causes of the flattening in the density spectrum. Both numerical and experimental approaches point towards an important role played by Kinetic Alfvén Waves.</p>

scholarly journals Theoretical perspective on strangeness production

2018 ◽  
Vol 171 ◽  
pp. 03002 ◽  
Author(s):  
Che Ming Ko
Keyword(s):  
Particle Production ◽  
Theoretical Perspective ◽  
Mean Field ◽  
Dense Matter ◽  
Heavy Ion ◽  
Density Fluctuations ◽  
Strangeness Production ◽  
Ion Collisions ◽  
Strange Hadron ◽  
Exotic Hadrons

A brief review of some highlights and puzzles on strangeness production in heavy ion collisions is given. These include strangeness production and the nuclear equation of state; deeply subthreshold strangeness production; mean-field potentials on strange hadrons; phi meson in dense matter; anomalous strange hadron to pion ratios; density fluctuations on particle production; A hyperon polarization and the vorticity field, and exotic hadrons.

scholarly journals Flattening of the Density Spectrum in Compressible Hall-MHD Simulations

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1162
Author(s):  
Victor Montagud-Camps ◽  
František Němec ◽  
Jana Šafránková ◽  
Zdeněk Němeček ◽  
Andrea Verdini ◽  
...  
Keyword(s):  
Transition Region ◽  
Cyclotron Frequency ◽  
Density Fluctuations ◽  
Proton Density ◽  
Spectral Slope ◽  
Plasma Parameters ◽  
Mhd Simulation ◽  
Density Spectrum ◽  
Mhd Simulations ◽  
Hall Mhd

Observations of proton density fluctuations of the solar wind at 1 au have shown the presence of a decade-long transition region of the density spectrum above sub-ion scales, characterized by a flattening of the spectral slope. We use the proton density fluctuations data collected by the BMSW instrument on-board the Spektr-R satellite in order to delimit the plasma parameters under which the transition region can be observed. Under similar plasma conditions to those in observations, we carry out 3D compressible magnetohydrodynamics (MHD) and Hall-MHD numerical simulations and find that Hall physics is necessary to generate the transition region. The analysis of the kω power spectrum in the Hall-MHD simulation indicates that the flattening of the density spectrum is associated with fluctuations having frequencies smaller than the ion cyclotron frequency.

scholarly journals A study of event-by-event fluctuations in relativistic heavy-ion collisions

2014 ◽  
Vol 23 (11) ◽  
pp. 1450065 ◽  
Author(s):  
Shakeel Ahmad ◽  
M. M. Khan ◽  
Shaista Khan ◽  
A. Khatun ◽  
M. Irfan
Keyword(s):  
Monte Carlo ◽  
Particle Density ◽  
Heavy Ion ◽  
Density Fluctuations ◽  
Relativistic Heavy Ion Collisions ◽  
Final States ◽  
Factorial Moments ◽  
Ion Collisions ◽  
Dynamical Fluctuations ◽  
Scaled Factorial Moments

A method for selecting events with densely populated narrow regions or spikes in a given data sample is discussed. Applying this method to 200 A GeV/c 32 S - AgBr and 32 S -Gold collision data, a few events having "hot regions" are chosen for further analysis. The finding reveals that a systematic study of particle density fluctuations, if carried out in terms of scaled factorial moments, and the results are compared with those for the analysis of correlation free Monte Carlo events, would be useful in identifying events with large dynamical fluctuations. Formation of clusters or jet-like structure in multihadronic final states in the selected spiky events is also looked into and compared with the predictions of AMPT and independent emission hypothesis models by carrying out Monte Carlo simulation. The findings suggest that clustering or jet-like algorithm adopted in the present study may also serve as an important tool for triggering different classes of events.

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