Physics of particle collisions at high energies: Limits to phenomenology, Part 1

2008 ◽  
Vol 86 (7) ◽  
pp. 883-897 ◽  
Author(s):  
G Sau ◽  
S K Biswas ◽  
B De ◽  
P Guptaroy ◽  
A Bhattacharya ◽  
...  
Keyword(s):  
Good Description ◽  
Heavy Ion ◽  
High Energy ◽  
Data Sets ◽  
Particle Interactions ◽  
Power Law Model ◽  
Particle Collisions ◽  
Relativistic Heavy Ion Collider ◽  
High Energies ◽  
200 Gev

Interpretation and understanding of high-energy PP data in a clear, consistent, and comprehensive manner is crucial for making valid claims to build up any successful theoretical framework for particle interactions. We have tried here to analyze the various sets of PP data available from the pre-ISR days to the latest PP collisions at the relativistic heavy ion collider (RHIC) experiment at [Formula: see text] = 200 GeV in the light of a power-law model. Both mid-rapidity and high-rapidity data sets have been dealt with by applying the same working formula. It is found that the working formula used provides a good description of these wide ranging data sets; but hardly throws any deep insights into the nature of particle interactions that force us to question the worth and rigour of phenomenological studies.PACS Nos.: 13.60.Hb, 13.60.Le, 13.85.Ni

Physics of particle collisions at high energies: Limits to phenomenology, Part 2

2008 ◽  
Vol 86 (7) ◽  
pp. 899-910 ◽  
Author(s):  
G Sau ◽  
S K Biswas ◽  
B De ◽  
P Guptaroy ◽  
A Bhattacharya ◽  
...  
Keyword(s):  
Phenomenological Model ◽  
Phenomenological Approach ◽  
Heavy Ion ◽  
Particle Collisions ◽  
Pp Collisions ◽  
Relativistic Heavy Ion Collider ◽  
High Energies ◽  
Fermi National Accelerator Laboratory ◽  
Fair Degree

Our focus in this work would be concentrated on trying to understand the nature of some very important observables measured for deuteron–gold (d + Au) collisions at relativistic heavy ion collider (RHIC) energies in the light of a particular phenomenological model that we had applied earlier in analyzing data for PP collisions at RHIC and Fermi National Accelerator Laboratory (FNAL) energies with a fair degree of success. In this particular case, as well, our observations and conclusions are exactly similar to those in our previous work. The emphatic ending points, on the whole, to some gross limitations of the chosen phenomenological approach in particular and of the phenomenology as such in general.PACS Nos.: 13.60.Hb, 13.60.Le, 13.60.Rj, 13.85.Ni

scholarly journals General dispersion properties of magnetized plasmas with drifting bi-Kappa distributions. DIS-K: Dispersion Solver for Kappa Plasmas

2021 ◽  
Vol 87 (3) ◽  
Author(s):  
R.A. López ◽  
S.M. Shaaban ◽  
M. Lazar
Keyword(s):  
Dominant Role ◽  
High Energy ◽  
Distribution Functions ◽  
Magnetized Plasma ◽  
Unstable Wave ◽  
Space Plasmas ◽  
Good Representation ◽  
Particle Interactions ◽  
Particle Collisions ◽  
Dispersion Tensor

Space plasmas are known to be out of (local) thermodynamic equilibrium, as observations show direct or indirect evidences of non-thermal velocity distributions of plasma particles. Prominent are the anisotropies relative to the magnetic field, anisotropic temperatures, field-aligned beams or drifting populations, but also, the suprathermal populations enhancing the high-energy tails of the observed distributions. Drifting bi-Kappa distribution functions can provide a good representation of these features and enable for a kinetic fundamental description of the dispersion and stability of these collision-poor plasmas, where particle–particle collisions are rare but wave–particle interactions appear to play a dominant role in the dynamics. In the present paper we derive the full set of components of the dispersion tensor for magnetized plasma populations modelled by drifting bi-Kappa distributions. A new solver called DIS-K (DIspersion Solver for Kappa plasmas) is proposed to solve numerically the dispersion relations of high complexity. The solver is validated by comparing with the damped and unstable wave solutions obtained with other codes, operating in the limits of drifting Maxwellian and non-drifting Kappa models. These new theoretical tools enable more realistic characterizations, both analytical and numerical, of wave fluctuations and instabilities in complex kinetic configurations measured in-situ in space plasmas.

scholarly journals On Pseudorapidity Distribution and Speed of Sound in High Energy Heavy Ion Collisions Based on a New Revised Landau Hydrodynamic Model

2015 ◽  
Vol 2015 ◽  
pp. 1-23 ◽  
Author(s):  
Li-Na Gao ◽  
Fu-Hu Liu
Keyword(s):  
Speed Of Sound ◽  
Hydrodynamic Model ◽  
Quark Gluon Plasma ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Relativistic Heavy Ion Collider ◽  
Central Source ◽  
Ion Collisions

We propose a new revised Landau hydrodynamic model to study systematically the pseudorapidity distributions of charged particles produced in heavy ion collisions over an energy range from a few GeV to a few TeV per nucleon pair. The interacting system is divided into three sources, namely, the central, target, and projectile sources, respectively. The large central source is described by the Landau hydrodynamic model and further revised by the contributions of the small target/projectile sources. The modeling results are in agreement with the available experimental data at relativistic heavy ion collider, large hadron collider, and other energies for different centralities. The value of square speed of sound parameter in different collisions has been extracted by us from the widths of rapidity distributions. Our results show that, in heavy ion collisions at energies of the two colliders, the central source undergoes a phase transition from hadronic gas to quark-gluon plasma liquid phase; meanwhile, the target/projectile sources remain in the state of hadronic gas. The present work confirms that the quark-gluon plasma is of liquid type rather than being of a gas type.

scholarly journals Probing jet medium interactions via Z(H) + jet momentum imbalances

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Lin Chen ◽  
Shu-Yi Wei ◽  
Han-Zhong Zhang
Keyword(s):  
Transport Coefficient ◽  
Good Description ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Jet Quenching ◽  
Quenching Effect ◽  
Nuclear Collisions ◽  
Ion Collisions ◽  
Pqcd Approach

AbstractDifferent types of high energy hard probes are used to extract the jet transport properties of the Quark-Gluon Plasma created in heavy-ion collisions, of which the heavy boson tagged jets are undoubtedly the most sophisticated due to its clean decay signature and production mechanism. In this study, we used the resummation improved pQCD approach with high order correction in the hard factor to calculate the momentum ratio $$x_J$$ x J distributions of Z and Higgs (H) tagged jets. We found that the formalism can provide a good description of the 5.02 TeV pp data. Using the BDMPS energy loss formalism, along with the OSU 2 + 1D hydro to simulate the effect of the medium, we extracted the value of the jet transport coefficient to be around $${\hat{q}}_0=4\sim 8~\text {GeV}^2/\text {fm}$$ q ^ 0 = 4 ∼ 8 GeV 2 / fm by comparing with the Z + jet PbPb experimental data. The H + jet $$x_J$$ x J distribution were calculated in a similar manner in contrast and found to have a stronger Sudakov effect as compared with the Z + jet distribution. This study uses a clean color-neutral boson as trigger to study the jet quenching effect and serves as a complimentary method in the extraction of the QGP’s transport coefficient in high energy nuclear collisions.

scholarly journals Chiral Magnetic Effects in Nuclear Collisions

2020 ◽  
Vol 70 (1) ◽  
pp. 293-321 ◽  
Author(s):  
Wei Li ◽  
Gang Wang
Keyword(s):  
National Laboratory ◽  
Hadron Collider ◽  
Transport Phenomena ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Brookhaven National Laboratory ◽  
Relativistic Heavy Ion Collider ◽  
Nuclear Collisions ◽  
Chiral Magnetic Effect

The interplay of quantum anomalies with strong magnetic fields and vorticity in chiral systems could lead to novel transport phenomena, such as the chiral magnetic effect (CME), the chiral magnetic wave (CMW), and the chiral vortical effect (CVE). In high-energy nuclear collisions, these chiral effects may survive the expansion of a quark–gluon plasma fireball and be detected in experiments. The experimental searches for the CME, the CMW, and the CVE have aroused extensive interest over the past couple of decades. The main goal of this article is to review the latest experimental progress in the search for these novel chiral transport phenomena at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory and the Large Hadron Collider at CERN. Future programs to help reduce uncertainties and facilitate the interpretation of the data are also discussed.

scholarly journals Monitoring the Extragalactic High Energy Sky

Galaxies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 9 ◽  
Author(s):  
Jean-Philippe Lenain
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
High Energy ◽  
Line Of Sight ◽  
Data Sets ◽  
High Energies ◽  
Multi Wavelength ◽  
Rich Data ◽  
Very High

Blazars are jetted active galactic nuclei with a jet pointing close to the line of sight, hence enhancing their intrinsic luminosity and variability. Monitoring these sources is essential in order to catch them flaring and promptly organize follow-up multi-wavelength observations, which are key to providing rich data sets used to derive e.g., the emission mechanisms at work, and the size and location of the flaring zone. In this context, the Fermi-LAT has proven to be an invaluable instrument, whose data are used to trigger many follow-up observations at high and very high energies. A few examples are illustrated here, as well as a description of different data products and pipelines, with a focus given on FLaapLUC, a tool in use within the H.E.S.S. collaboration.

scholarly journals Comparing Standard Distribution and Its Tsallis Form of Transverse Momenta in High Energy Collisions

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Rui-Fang Si ◽  
Hui-Ling Li ◽  
Fu-Hu Liu
Keyword(s):  
Hadron Collider ◽  
Simulated Data ◽  
Heavy Ion ◽  
High Energy ◽  
Central Nucleus ◽  
Quantum Molecular Dynamics ◽  
Relativistic Heavy Ion Collider ◽  
Two Component ◽  
Standard Distribution ◽  
Effective Temperatures

The experimental (simulated) transverse momentum spectra of negatively charged pions produced at midrapidity in central nucleus-nucleus collisions at the Heavy-Ion Synchrotron (SIS), Relativistic Heavy-Ion Collider (RHIC), and Large Hadron Collider (LHC) energies obtained by different collaborations are selected by us to investigate, where a few simulated data are taken from the results of FOPI Collaboration which uses the IQMD transport code based on Quantum Molecular Dynamics. A two-component standard distribution and the Tsallis form of standard distribution are used to fit these data in the framework of a multisource thermal model. The excitation functions of main parameters in the two distributions are analyzed. In particular, the effective temperatures extracted from the two-component standard distribution and the Tsallis form of standard distribution are obtained, and the relation between the two types of effective temperatures is studied.

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