INITIAL STATE SCATTERING AND J/Ψ HADROPRODUCTION ON NUCLEI

1992 ◽  
Vol 07 (39) ◽  
pp. 3631-3638
Author(s):  
V.A. SALEEV ◽  
N.P. ZOTOV
Keyword(s):  
Nuclear Matter ◽  
Major Part ◽  
Initial State ◽  
Dominant Mechanism ◽  
Suppression Effect ◽  
High Energies ◽  
Quark Models ◽  
Good Agreement

The pT-spectra of J/Ψ in hadron-nucleus and nucleus-nucleus collisions at high energies are investigated in a model where gg→J/Ψg is assumed to be the dominant mechanism. The initial state scattering using the additive quark models is taken into account. We demonstrate good agreement between the J/ΨpT-spectra and our results. It is shown that the allowance for the quark re-scattering and J/Ψ absorption in nuclear matter makes it possible to describe at least the major part of the J/Ψ suppression effect in collisions of relativistic nuclei.

VMC CALCULATIONS OF THE GROUND STATE PROPERTIES OF NUCLEAR MATTER

2005 ◽  
Vol 14 (02) ◽  
pp. 255-267 ◽  
Author(s):  
KAAN MANİSA ◽  
ÜLFET ATAV ◽  
RIZA OGUL
Keyword(s):  
Nuclear Matter ◽  
Ground State ◽  
Nucleon Nucleon ◽  
Neutron Matter ◽  
Potential Term ◽  
Ground State Properties ◽  
Dependent Potential ◽  
Variational Monte Carlo Method ◽  
Kinetic And Potential Energies ◽  
Good Agreement

A Variational Monte Carlo method (VMC) is described for the evaluation of the ground state properties of nuclear matter. Equilibrium properties of symmetric nuclear matter and neutron matter are calculated by the described VMC method. The Urbana ν14 potential is used for the nucleon–nucleon interactions in the calculations. Three- and more-body interactions are included as a density dependent potential term. Total, kinetic and potential energies per particle are obtained for nuclear and neutron matter. Pressure values of nuclear and neutron matter are also calculated at various densities. The binding energy of nuclear matter is found to be -16.06 MeV at a saturation density of 0.16 fm -3. The results obtained are in good agreement with those obtained by various authors with different potentials and techniques.

Non-Equilibrium Critical Relaxation of Heisenberg Ferromagnets with Long-Range Correlated Defects

2012 ◽  
Vol 190 ◽  
pp. 39-42
Author(s):  
M. Medvedeva ◽  
Pavel V. Prudnikov
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Critical Behavior ◽  
Critical Exponents ◽  
Heisenberg Model ◽  
Three Dimensional ◽  
Initial State ◽  
Short Time ◽  
Theoretic Description ◽  
Good Agreement

The dynamic critical behavior of the three-dimensional Heisenberg model with longrangecorrelated disorder was studied by using short-time Monte Carlo simulations at criticality.The static and dynamic critical exponents are determined. The simulation was performed fromordered initial state. The obtained values of the exponents are in a good agreement with resultsof the field-theoretic description of the critical behavior of this model in the two-loopapproximation.

scholarly journals Bottomonia production and polarization in the NRQCD with $$k_T$$-factorization. I: $$\Upsilon (3S)$$ and $$\chi _b(3P)$$ mesons

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
N. A. Abdulov ◽  
A. V. Lipatov
Keyword(s):  
Bound States ◽  
Spin Density Matrix ◽  
Unintegrated Gluon ◽  
Factorization Approach ◽  
Transverse Momentum Dependent ◽  
High Energies ◽  
Radiation Theory ◽  
Multipole Radiation ◽  
Shell Production ◽  
Good Agreement

Abstract The $$\Upsilon (3S)$$Υ(3S) production and polarization at high energies is studied in the framework of $$k_T$$kT-factorization approach. Our consideration is based on the non-relativistic QCD formalism for bound states formation and off-shell production amplitudes for hard partonic subprocesses. The transverse momentum dependent (TMD, or unintegrated) gluon densities in a proton were derived from the Ciafaloni-Catani-Fiorani-Marchesini (CCFM) evolution equation as well as from the Kimber–Martin–Ryskin (KMR) prescription. Treating the non-perturbative color octet transitions in terms of the multipole radiation theory and taking into account feed-down contributions from radiative $$\chi _b(3P)$$χb(3P) decays, we extract the corresponding non-perturbative matrix elements for $$\Upsilon (3S)$$Υ(3S) and $$\chi _b(3P)$$χb(3P) mesons from a combined fit to $$\Upsilon (3S)$$Υ(3S) transverse momenta distributions measured by the CMS and ATLAS Collaborations at the LHC energies $$\sqrt{s} = 7$$s=7 and 13 TeV and central rapidities. Then we apply the extracted values to describe the CDF and LHCb data on $$\Upsilon (3S)$$Υ(3S) production and to investigate the polarization parameters $$\lambda _\theta $$λθ, $$\lambda _\phi $$λϕ and $$\lambda _{\theta \phi }$$λθϕ, which determine the $$\Upsilon (3S)$$Υ(3S) spin density matrix. Our predictions have a good agreement with the currently available data within the theoretical and experimental uncertainties.

Quark models of nuclear matter

1992 ◽  
Vol 536 (3-4) ◽  
pp. 669-696 ◽  
Author(s):  
C.J. Horowitz ◽  
J. Piekarewicz
Keyword(s):  
Nuclear Matter ◽  
Quark Models

scholarly journals Central and peripheral hadron–nucleus collisions in the Additive Quark Model

2019 ◽  
Vol 34 (06) ◽  
pp. 1950048
Author(s):  
G. H. Arakelyan ◽  
Yu. M. Shabelski ◽  
A. G. Shuvaev
Keyword(s):  
Experimental Data ◽  
Quark Model ◽  
Constituent Quark ◽  
High Energies ◽  
Central Collisions ◽  
Energy Formula ◽  
Incident Nucleon ◽  
Good Agreement

Peripheral nucleon–nucleus collisions occur at high energies mainly through the interaction with one constituent quark from the incident nucleon. The central collisions should involve all three constituent quarks and each of them can interact several times. We calculate the average number of quark–nucleus interactions for both the cases in good agreement with the experimental data on [Formula: see text]-meson, [Formula: see text] and all charged secondaries productions in [Formula: see text] collisions at LHC energy [Formula: see text] TeV.

PSEUDORAPIDITY DISTRIBUTION OF CHARGED PARTICLES IN $p\bar p$ AND AA COLLISIONS AT HIGH ENERGIES

2005 ◽  
Vol 14 (04) ◽  
pp. 579-586
Author(s):  
FU SONG ◽  
FU-HU LIU
Keyword(s):  
Center Of Mass ◽  
Charged Particles ◽  
Pseudorapidity Distribution ◽  
Mass Energy ◽  
Center Of Mass Energy ◽  
High Energies ◽  
Cylinder Model ◽  
Energy Formula ◽  
Good Agreement ◽  
Aa Collisions

The pseudorapidity distributions of charged particles produced in [Formula: see text] annihilations and AA collisions at high energies are investigated by using a revised thermalized cylinder model. The Monte Carlo calculated results are compared and found to be in good agreement with the experimental data of [Formula: see text] annihilations at center-of-mass energy [Formula: see text], 546, 200, and 53 GeV, Au–Au collisions at [Formula: see text] and 130 A GeV, and Pb–Pb collisions at [Formula: see text].

scholarly journals Effective Markovian description of decoherence in bound systems

2014 ◽  
Vol 92 (2) ◽  
pp. 168-178 ◽  
Author(s):  
A.S. Sanz
Keyword(s):  
Degrees Of Freedom ◽  
Energy Levels ◽  
Dynamical Process ◽  
Initial State ◽  
Physical Mechanisms ◽  
State Diffusion ◽  
Decoherence Rate ◽  
Quantum State Diffusion ◽  
Insight Into ◽  
Good Agreement

Effective descriptions accounting for the evolution of quantum systems that are acted on by a bath are desirable. As the number of bath degrees of freedom increases and full quantum simulations turn out computationally prohibitive, simpler models become essential to understand and gain an insight into the main physical mechanisms involved in the system dynamics. In this regard, vibrational decoherence of an I2 diatomics is tackled here within the framework of Markovian quantum state diffusion. The I2 dynamics are analyzed in terms of an effective decoherence rate, Λ, and the specific choice of the initial state, in particular, Gaussian wave packets and two-state superpositions. It is found that, for Markovian baths, the relevant quantity regarding decoherence is the product of friction (η) and temperature (T); there is no distinction between varying one or the other. It is also observed that decoherence becomes faster as the energy levels involved in the system state correspond to higher eigenvalues. This effect is due to a population redistribution during the dynamical process and an eventual irreversible loss of the initial coherence. These results have been compared with those available in the literature from more detailed semiclassical IVR simulations, finding a good agreement.

scholarly journals Strangeness Enhancement at LHC Energies Using the Thermal Model and EPOSLHC Event Generator

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Mahmoud Hanafy ◽  
Omnia S. A. Qandil ◽  
Asmaa G. Shalaby
Keyword(s):  
Cosmic Ray ◽  
Heavy Ion ◽  
Event Generator ◽  
Relativistic Heavy Ion Collider ◽  
Model Calculations ◽  
High Energies ◽  
Particle Ratios ◽  
Strangeness Enhancement ◽  
The Mean ◽  
Good Agreement

The strangeness enhancement signature of QGP formation at LHC energies is carefully tackled in the present study. Based on HRG, the particle ratios of mainly strange and multistrange particles are studied at energies from lower s ~ 0.001 up to 13 TeV. The strangeness enhancement clearly appeared at more high energies, and the ratios are confronted to the available experimental data. The particle ratios are also studied using the Cosmic Ray Monte Carlo (CRMC) interface model with its two different event generators, namely, EPOS 1.99 and EPOSlhc, which show a good agreement with the model calculations at the whole range of the energy. We utilize them to produce some particles ratios. EPOS 1.99 is used to estimate particle ratios at lower energies from AGS up to the Relativistic Heavy Ion Collider (RHIC) while EPOSlhc is used at LHC energies. The production of kaons and lambda particles is studied in terms of the mean multiplicity in p-p collisions at energies ranging from 4 to 26 GeV. We find that both HRG model and the used event generators, EPOS 1.99 and EPOSlhc, can describe the particle ratios very well. Additionally, the freeze-out parameters are estimated for different collision systems, such as p-p and Pb-Pb, at LHC energies using both models.

scholarly journals Research on Frequency Doubling Effect of Thermoacoustic Speaker Based on Graphene Film

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6030
Author(s):  
Licheng Deng ◽  
Xingyue He ◽  
Surong He ◽  
Qingying Ren ◽  
Jiang Zhao ◽  
...  
Keyword(s):  
Sound Pressure ◽  
Graphene Film ◽  
Frequency Doubling ◽  
Suppression Effect ◽  
Laser Scribing ◽  
Dc Excitation ◽  
One Step ◽  
Ac Excitation ◽  
Screen Printing Technology ◽  
Good Agreement

In this work, the frequency doubling effect of thermoacoustic speakers is studied, and a method is analyzed to suppress the frequency doubling effect. Three cases were analyzed by superimposing the DC bias on the AC excitation: (1) DC is less than AC; (2) DC is equal to AC; (3) DC is greater than AC. We found that the frequency doubling effect can be well suppressed by superimposing a larger DC excitation on the AC excitation. The laser scribing technology was used to prepare graphene film in only one step, and the screen printing technology was used to prepare conductive electrodes. The microphone and B&K system was used to record the sound pressure level and study the suppression of frequency doubling effect. Finally, the sound pressure levels with the three different kinds of excitations were measured. The measured results show that they have a good agreement with the theoretical results. The suppression effect will be better when DC amplitude is greater than AC amplitude. Therefore, this work has certain reference significance for the further study and application of thermoacoustic speakers.

scholarly journals Hindcasting to measure ice sheet model sensitivity to initial states

2012 ◽  
Vol 6 (6) ◽  
pp. 5069-5094 ◽  
Author(s):  
A. Aschwanden ◽  
G. Aðalgeirsdóttir ◽  
C. Khroulev
Keyword(s):  
Mass Loss ◽  
Sea Level ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Initial State ◽  
Multiple Observations ◽  
Elevation Changes ◽  
Initial States ◽  
Global Mean Sea Level ◽  
Good Agreement

Abstract. Recent observations of the Greenland ice sheet indicate rapid mass loss at an accelerating rate with an increasing contribution to global mean sea level. Ice sheet models are used for projections of such future contributions of ice sheets to sea level, but the quality of projections is difficult to measure directly. Realistic initial states are crucial for accurate simulations. To test initial states we use hindcasting, i.e. forcing a model with known or closely-estimated inputs for past events to see how well the output matches observations. By simulating the recent past of Greenland, and comparing to observations of ice thickness, ice discharge, surface speeds, mass loss and surface elevation changes for validation, we find that the short term model response is strongly influenced by the initial state. We show that the dynamical state can be mis-represented despite a good agreement with some observations, stressing the importance of using multiple observations. Some initial states generate good agreement with measured mass time series in the hindcast period, and good agreement with present-day kinematic fields. We suggest hindcasting as a methodology for careful validation of initial states that can be done before making projections on decadal to century time-scales.

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