scholarly journals Experimental Test of Spontaneous Correlation and Anomalous Sensitivity in Finite Highly Excited Many-Body Systems

2003 ◽  
Vol 12 (03) ◽  
pp. 377-393 ◽  
Author(s):  
Qi Wang ◽  
Sergey Yu Kun ◽  
Wendong Tian ◽  
Songlin Li ◽  
Zhonghe Jiang ◽  
...  
Keyword(s):  
Cross Sections ◽  
Experimental Test ◽  
Heavy Ion ◽  
Quantum Systems ◽  
Slow Phase ◽  
Many Body ◽  
Ion Collisions ◽  
Excited Complex ◽  
Many Body Systems ◽  
Phase Randomization

We have tested recent suggestion of anomalous sensitivity in highly excited quantum many-body systems. Two independent measurements of cross sections for the 19 F + 93 Nb strongly dissipative heavy-ion collisions have been performed at incident energies from 102 to 108 MeV in steps of 250 keV. In the two measurements we used different, independently prepared, 93Nb target foils with nominally the same thickness. The data indicate statistically significant non-reproducibility of the energy oscillating yields in the two measurements. The observed non-reproducibility is consistent with recent theoretical arguments on spontaneous correlation, slow phase randomization and chaos in highly excited complex quantum systems.

Total and differential cross sections for pion production via coherent isobar and giant resonance formation in heavy-ion collisions

1985 ◽  
Vol 63 (9) ◽  
pp. 1242-1248 ◽  
Author(s):  
P. A. Deutchman ◽  
J. W. Norbury ◽  
L. W. Townsend
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Pion Production ◽  
Giant Resonance ◽  
Heavy Ion ◽  
Differential Cross Sections ◽  
Many Body ◽  
Peripheral Collision ◽  
Ion Collisions ◽  
Pion Energy

A quantal many-body formalism is presented that investigates pion production through the coherent formation of a nucleonic isobar in the projectile and its subsequent decay to various pion charge states along with concomitant excitation of the target to a coherent spin–isospin giant resonance via a peripheral collision of relativistic heavy ions. Total cross sections as a function of the incident energy per nucleon and Lorentz-invariant differential cross sections as a function of pion energy and angle are calculated. It is shown that the pion angular distributions, in coincidence with the target giant resonance excitations, might provide a well-defined signature for these coherent processes.

CHARMONIUM PRODUCTION IN Pb–Pb COLLISIONS AT ALICE: FROM SUPPRESSION TO REGENERATION?

2013 ◽  
Vol 28 (21) ◽  
pp. 1330018 ◽  
Author(s):  
ENRICO SCOMPARIN
Keyword(s):  
Phase Transition ◽  
Cross Sections ◽  
Short Review ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Alice Experiment ◽  
Model Calculations ◽  
Ion Collisions ◽  
Quark Production ◽  
History Of

Heavy quarkonium states are considered as one of the key observables for the study of the phase transition from a system made of hadrons towards a Quark–Gluon Plasma (QGP). In the last 25 years, experiments at CERN and Brookhaven have studied collisions of heavy ions looking for a suppression of charmonia/bottomonia, considered as a signature of the phase transition. After an introduction to the main concepts behind these studies and a short review of the SPS and RHIC results, I will describe the results obtained in Pb – Pb collisions by the ALICE experiment at the LHC. The ALICE findings will be critically compared to those of lower energy experiments, to CMS results, and to model calculations. The large cross-sections for heavy-quark production at LHC energies are expected to induce a novel production mechanism for charmonia in heavy-ion collisions, related to a recombination of [Formula: see text] pairs along the history of the collision and/or at hadronization. The occurrence of such a process at the LHC will be discussed. Finally, prospects for future measurements will be shortly addressed.

scholarly journals Probing Many-Body Systems Near Spectral Degeneracies

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1796
Author(s):  
Klaus Ziegler
Keyword(s):  
Decay Rate ◽  
Correlation Matrix ◽  
Time Correlation ◽  
General Concept ◽  
Quantum Systems ◽  
Quantum Evolution ◽  
Many Body ◽  
Space Localization ◽  
Many Body Systems ◽  
Random Times

The diagonal elements of the time correlation matrix are used to probe closed quantum systems that are measured at random times. This enables us to extract two distinct parts of the quantum evolution, a recurrent part and an exponentially decaying part. This separation is strongly affected when spectral degeneracies occur, for instance, in the presence of spontaneous symmetry breaking. Moreover, the slowest decay rate is determined by the smallest energy level spacing, and this decay rate diverges at the spectral degeneracies. Probing the quantum evolution with the diagonal elements of the time correlation matrix is discussed as a general concept and tested in the case of a bosonic Josephson junction. It reveals for the latter characteristic properties at the transition to Hilbert-space localization.

Cross sections for photons produced in the stopping phase in relativistic heavy-ion collisions

1989 ◽  
Vol 504 (4) ◽  
pp. 864-874 ◽  
Author(s):  
Joachim Thiel ◽  
Thomas Lippert ◽  
Norbert Grün ◽  
Werner Scheid
Keyword(s):  
Cross Sections ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Ion Collisions

scholarly journals Dielectron Production in Proton–Proton Collisions at √s=7 TeV with ALICE

Proceedings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 24
Author(s):  
Sebastian Scheid
Keyword(s):  
Cross Sections ◽  
Mass Range ◽  
Heavy Ion ◽  
Event Generator ◽  
Leading Order ◽  
Proton Proton ◽  
Total Cross Sections ◽  
Proton Collisions ◽  
Ion Collisions ◽  
Proton Proton Collisions

The ALICE Collaboration measured dielectron production as a function of the invariant mass ( m ee ), the pair transverse momentum ( p T , ee ) and the pair distance of closest approach ( DCA ee ) in pp collisions at s = 7 TeV. Prompt and non-prompt dielectron sources can be separated with the DCA ee , which will give the opportunity in heavy-ion collisions to identify thermal radiation from the medium in the intermediate-mass range dominated by contributions from open-charm and beauty hadron decays. The charm and beauty total cross sections are extracted from the data by fitting the spectra with two different MC generators, i.e., PYTHIA a leading order event generator and POWHEG a next-to-leading order event generator. Significant model dependences are observed, reflecting the sensitivity of this measurement to the heavy-flavour production mechanisms.

scholarly journals An Experimental Review on Elliptic Flow of Strange and Multistrange Hadrons in Relativistic Heavy Ion Collisions

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Shusu Shi
Keyword(s):  
Large Hadron Collider ◽  
Cross Sections ◽  
Heavy Ion Collisions ◽  
Hadron Collider ◽  
Elliptic Flow ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Relativistic Heavy Ion Collider ◽  
Flow Measurements ◽  
Ion Collisions

Strange hadrons, especially multistrange hadrons, are good probes for the early partonic stage of heavy ion collisions due to their small hadronic cross sections. In this paper, I give a brief review on the elliptic flow measurements of strange and multistrange hadrons in relativistic heavy ion collisions at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC).

COMPARISON OF THE FUSION-FISSION AND QUASIFISSION MECHANISMS IN HEAVY-ION COLLISIONS

2009 ◽  
Vol 18 (04) ◽  
pp. 841-849 ◽  
Author(s):  
AVAZBEK NASIROV ◽  
GIOVANNI FAZIO ◽  
GIORGIO GIARDINA ◽  
GIUSEPPE MANDAGLIO ◽  
MARINA MANGANARO ◽  
...  
Keyword(s):  
Cross Sections ◽  
Theoretical Method ◽  
Heavy Ion ◽  
Evaporation Residue ◽  
System Model ◽  
Complete Fusion ◽  
Dinuclear System ◽  
Ion Collisions ◽  
Partial Fusion ◽  
Evaporation Residues

The decrease of the evaporation residue yields in reactions with massive nuclei is explained by an increase of the competition between quasifission and complete fusion processes and by the decrease of the survival probability of the heated and rotating nuclei against fission along the de-excitation cascade of the compound nucleus. The experimental data on the yields of evaporation residue, fusion-fission and quasifission fragments in the 48 Ca + 154 Sm reaction are analyzed in the framework of the combined theoretical method based on the dinuclear system concept and advanced statistical model. The measured yields of evaporation residues of the 48 Ca + 154 Sm reaction have been well reproduced and yields of fission fragments were analyzed using the partial fusion and quasifission cross sections calculated in the dinuclear system model. Such a way of calculation is used to find optimal conditions for the synthesis of the new element Z = 120 (A = 302) by studying the excitation functions of evaporation residues of the 54 Cr + 248 Cm , 58 Fe + 244 Pu , and 64 Ni + 238 U reactions. Our estimations show that the 54 Cr + 248 Cm reaction is preferable in comparison with the two others.

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