scholarly journals Analysis of the flow systematics in Au+Au collisions

2019 ◽  
Vol 21 ◽  
pp. 37
Author(s):  
M. Veselsky ◽  
Yu-Gang Ma ◽  
G. A. Souliotis
Keyword(s):  
Energy Range ◽  
Density Dependence ◽  
Cross Sections ◽  
Symmetry Energy ◽  
Nucleon Nucleon ◽  
Additional Constraint ◽  
Free Nucleon ◽  
Global Trends ◽  
Resonance Data ◽  
Giant Monopole Resonance

The new implementation of the Boltzmann-Uhling-Uhlenbeck equation, the VdWBUU simulation (with EoS-dependent in-medium nucleon-nucleon cross sections) appears to reproduce the flow observables in the Au+Au collisions in the energy range from 400 AMeV to 10 AGeV. The range of the feasible stiffness of the EoS can be identified, based on the analysis presented here, as encompassing compressibilities starting from 250-260 MeV and above, and thus consistent with the results of re-analysis of the giant monopole resonance data (250-310 MeV). Using that additional constraint, the range of feasible values of the stiffness of density dependence can be set as γ=1−1.25, with the value γ=1 appearing as as a global value of stiffness of the symmetry energy feasible over the whole range of constrained compressibilities. The implementation of BUU with the free nucleon-nucleon cross sections can not describe correctly the global trends of flow observables.

Role of inelastic couplings in the 4He + 208Pb elastic scattering in a wide energy range

2021 ◽  
Author(s):  
Luiz Carlos Chamon ◽  
Leandro Romero Gasques ◽  
Juan Carlos Zamora Cardona
Keyword(s):  
Elastic Scattering ◽  
Energy Range ◽  
Energy Dependence ◽  
Cross Sections ◽  
Optical Model ◽  
Nucleon Nucleon ◽  
Scattering Data ◽  
Wide Energy Range ◽  
Data Analyses ◽  
Wide Energy

Abstract The phenomenological strengths of the real part of the optical potential, obtained from elastic scattering data analyses within the optical model approach, present significant energy-dependence. This behavior has been associated to the intrinsic energy-dependence of the effective nucleon-nucleon interaction. However, in earlier works, we proposed that at least part of this dependence can arise from the effect of couplings to inelastic states of the nuclei. In order to deepen this study, in this paper we present extensive data analyses for the elastic scattering and inelastic excitation of 111 states of 208Pb, for the 4He + 208Pb system in a wide energy range. With the purpose of comparison, the theoretical cross sections are obtained in different approaches for the imaginary part of the potential, and within both contexts: optical model (distorted wave Born approximation) and coupled-channel calculations.

THE DYNAMICAL ISOSPIN EFFECT ON PROTON-INDUCED REACTIONS ON Sn ISOTOPES

2008 ◽  
Vol 17 (09) ◽  
pp. 1648-1659
Author(s):  
ZHUXIA LI ◽  
LI OU
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Density Dependence ◽  
Cross Sections ◽  
Symmetry Energy ◽  
Reaction Cross ◽  
Quantum Molecular Dynamics ◽  
Incident Proton ◽  
Spallation Reactions ◽  
Reaction Cross Sections

In this talk we present a model, Improved Quantum Molecular Dynamics (ImQMD05) model incorporated with a Statistical Decay Model (SDM), to describe intermediate energy proton induced spallation reactions. A good agreement with experimental data of double differential cross sections of emitted neutrons is obtained. We further apply this model to study the isospin effect in proton induced spallation reactions on a series Sn isotope targets. We find that the systematic behavior of the reaction cross sections for Sn isotope targets deviates from the empirical expression obtained by fitting the experimental data for proton induced spallation reactions on target nuclei along β-stability line. The extent of the deviation depends on the density dependence of the symmetry energy strongly. We also find an obvious shift of the elastic scattering angular distribution of emitted protons when the symmetry energy is taken into account for neutron-rich Sn isotope targets and the angle shifted strongly depends on the stiffness of the symmetry energy. The attractive effect of the symmetry potential of target on incident proton directly influences the motion of the incident proton leading to strong isospin effect on the reaction dynamics and thus on these reaction observables. We conclude that the measurement of reaction cross sections and the elastic scattering angular distributions in proton induced spallation reactions on Sn isotopes can provide clear constraint for the density dependence of symmetry energy.

Isospin effects on pt-differential flow in heavy ion collisions at intermediate energies

2014 ◽  
Vol 23 (10) ◽  
pp. 1450062
Author(s):  
Rubina Bansal ◽  
Anupriya Jain ◽  
Suneel Kumar
Keyword(s):  
Density Dependence ◽  
Symmetry Energy ◽  
Heavy Ion Collisions ◽  
Dominant Role ◽  
Heavy Ion ◽  
Nucleon Nucleon ◽  
Transverse Flow ◽  
Intermediate Energies ◽  
Ion Collisions ◽  
Isospin Dependence

This paper aims to study the role of isospin degree of freedom in heavy-ion collisions through the transverse momentum (pt), neutron to proton ratio and system mass dependence of pt-differential transverse flow. Our study shows that (pt)-differential transverse flow dependence can act as sensitive probe to study symmetry energy and its density dependence compared to the energy of vanishing flow. Symmetry energy and its density dependence play a dominant role over the isospin-dependence of nucleon–nucleon cross-section at Fermi energy.

CROSS SECTIONS OF (p, xn) REACTIONS IN THE ISOTOPE OF LEAD AND BISMUTH

1956 ◽  
Vol 34 (8) ◽  
pp. 745-766 ◽  
Author(s):  
R. E. Bell ◽  
H. M. Skarsgard
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Proton Energy ◽  
Neutron Cross Section ◽  
Smooth Curve ◽  
Nucleon Nucleon ◽  
Reaction Cross ◽  
Total Reaction Cross Section

Measurements have been made by the activation method of cross sections of (p, xn) reactions in Bi209, Pb206, Pb207, and Pb208. The present results cover x = 3 to 7 in Bi209, 2 to 6 in Pb206, 2 to 4 in Pb207, and 3 and 4 in Pb208, over a total proton energy range from 12 to 85 Mev. The absolute accuracy is about 15%. Each cross section plotted as a function of proton energy rises above its threshold to a peak whose height is of the order of one barn, and then falls again to a low and fairly constant value. The results from x = 3 to 7 are consistent with a compound nucleus plus prompt nucleon–nucleon cascade model using reasonable nuclear parameters, but the experimental (p, 2n) cross section appears to be almost double the value so predicted. Since (p, xn) reactions are dominant in the energy range 10 to 40 Mev., their sum approximates the total reaction cross section; the experimental sum fluctuates around the smooth curve computed for the compound nucleus model with r0 = 1.3 × 10−13 cm. The fluctuations are similar to, but more marked than, those in the total neutron cross section of heavy elements in the same energy range. A more detailed theoretical discussion of these results is given by Jackson in the paper immediately following.

L X-RAY FLUORESCENCE CROSS-SECTIONS MEASUREMENTS FOR ELEMENTS 56≤Z≤66 IN THE ENERGY RANGE 11-41 keV

1987 ◽  
Vol 48 (C9) ◽  
pp. C8-669-C8-672 ◽  
Author(s):  
S. SINGH ◽  
S. KUMAR ◽  
D. MEHTA ◽  
M. L. GARG ◽  
N. SINGH ◽  
...  
Keyword(s):  
Energy Range ◽  
Cross Sections ◽  
X Ray

scholarly journals Charmed and bottomed hadronic cross sections from a statistical model

2020 ◽  
Vol 56 (9) ◽  
Author(s):  
Gábor Balassa ◽  
György Wolf
Keyword(s):  
Statistical Model ◽  
Energy Range ◽  
Cross Sections ◽  
Heavy Quarks ◽  
Open Charm ◽  
Low Energy ◽  
Final State ◽  
Proton Antiproton ◽  
Proton Proton

Abstract In this work, we extended our statistical model with charmed and bottomed hadrons, and fit the quark creational probabilities for the heavy quarks, using low energy inclusive charmonium and bottomonium data. With the finalized fit for all the relevant types of quarks (up, down, strange, charm, bottom) at the energy range from a few GeV up to a few tens of GeV’s, the model is now considered complete. Some examples are also given for proton–proton, pion–proton, and proton–antiproton collisions with charmonium, bottomonium, and open charm hadrons in the final state.

scholarly journals Elastic Electron Scattering from Methane Molecule in the Energy Range from 50–300 eV

2021 ◽  
Vol 22 (2) ◽  
pp. 647
Author(s):  
Jelena Vukalović ◽  
Jelena B. Maljković ◽  
Karoly Tökési ◽  
Branko Predojević ◽  
Bratislav P. Marinković
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Electron Gun ◽  
Methane Molecule ◽  
Edge Plasma ◽  
Electron Interaction ◽  
Outer Planet ◽  
Elastic Electron

Electron interaction with methane molecule and accurate determination of its elastic cross-section is a demanding task for both experimental and theoretical standpoints and relevant for our better understanding of the processes in Earth’s and Solar outer planet atmospheres, the greenhouse effect or in plasma physics applications like vapor deposition, complex plasma-wall interactions and edge plasma regions of Tokamak. Methane can serve as a test molecule for advancing novel electron-molecule collision theories. We present a combined experimental and theoretical study of the elastic electron differential cross-section from methane molecule, as well as integral and momentum transfer cross-sections in the intermediate energy range (50–300 eV). The experimental setup, based on a crossed beam technique, comprising of an electron gun, a single capillary gas needle and detection system with a channeltron is used in the measurements. The absolute values for cross-sections are obtained by relative-flow method, using argon as a reference. Theoretical results are acquired using two approximations: simple sum of individual atomic cross-sections and the other with molecular effect taken into the account.

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