scholarly journals NUCLEAR SHADOWING EFFECTS ON CHARMONIUM PRODUCTION IN QCD

1998 ◽  
Vol 13 (06) ◽  
pp. 453-463 ◽  
Author(s):  
C. PAJARES ◽  
C. A. SALGADO ◽  
Yu. M. SHABELSKI
Keyword(s):  
Experimental Data ◽  
Structure Functions ◽  
Nuclear Medium ◽  
Color Singlet ◽  
Separate Study ◽  
Factorization Approach ◽  
Parton Distributions ◽  
Charmonium Production ◽  
Evaporation Model ◽  
Nonrelativistic Qcd

It is shown that the effects on charmonium production of the modification of nucleon parton distributions inside nuclei are similar in the factorization approach based on nonrelativistic QCD and in the color evaporation model. In the first model, a separate study of the color octet and color singlet contributions to the yields of the various charmonium states as well as the contributions of these states to the total J/ψ production is performed. It is found that a clear xF dependence of these contributions which, together with an overall normalization given by absorption of the pre-resonant [Formula: see text] state inside the nuclear medium, can reproduce experimental data a for moderate xF. However, at large xF, there is bigger suppression that cannot be fit by this overall normalization together with the shadowing of structure functions.

Validation of Film Evaporation Model in GASFLOW-MPI

2018 ◽  
Author(s):  
Li Yabing ◽  
Zhang Han ◽  
Xiao Jianjun
Keyword(s):  
Experimental Data ◽  
Wall Temperature ◽  
Cooling System ◽  
Numerical Study ◽  
Thermal Power ◽  
Heat Removal ◽  
Air Velocity ◽  
Evaporation Model ◽  
Film Evaporation ◽  
Test Region

A dynamic film model is developed in the parallel CFD code GASFLOW-MPI for passive containment cooling system (PCCS) utilized in nuclear power plant like AP1000 and CAP1400. GASFLOW-MPI is a widely validated parallel CDF code and has been applied to containment thermal hydraulics safety analysis for different types of reactors. The essential issue for PCCS is the heat removal capability. Research shows that film evaporation contributes most to the heat removal capability for PCCS. In this study, the film evaporation model is validated with separate effect test conducted on the EFFE facility by Pisa University. The test region is a rectangle gap with 0.1m width, 2m length, and 0.6m depth. The water film flowing from the top of the gap is heated by a heating plate with constant temperature and cooled by countercurrent air flow at the same time. The test region model is built and analyzed, through which the total thermal power and evaporation rate are obtained to compare with experimental data. Numerical result shows good agreement with the experimental data. Besides, the influence of air velocity, wall temperature and gap widths are discussed in our study. Result shows that, the film evaporation has a positive correlation with air velocity, wall temperature and gap width. This study can be fundamental for our further numerical study on PCCS.

scholarly journals ANALYSIS OF THE $B_q\to D_q(D_q^*)P$ AND $B_q\to D_q(D_q^*)V$ DECAYS WITHIN THE FACTORIZATION APPROACH IN QCD

2009 ◽  
Vol 24 (31) ◽  
pp. 5845-5860 ◽  
Author(s):  
K. AZIZI ◽  
R. KHOSRAVI ◽  
F. FALAHATI
Keyword(s):  
Experimental Data ◽  
Perturbative Qcd ◽  
Sum Rules ◽  
Branching Fraction ◽  
Form Factors ◽  
Transition Form ◽  
Qcd Sum Rules ◽  
Factorization Approach ◽  
Electroweak Penguin ◽  
Decay Widths

Using the factorization approach and considering the contributions of the current–current, QCD penguin and electroweak penguin operators at the leading approximation, the decay amplitudes and decay widths of [Formula: see text] and [Formula: see text] transitions, where q = u, d, s and P and V are pseudoscalar and vector mesons, are calculated in terms of the transition form factors of the Bq→Dq and [Formula: see text]. Having computed those form factors in three-point QCD sum rules, the branching fraction for these decays are also evaluated. A comparison of our results with the predictions of the perturbative QCD as well as the existing experimental data is presented.

Modelling the Natural Evaporation of the Concentrated Seawater after Desalinized

2015 ◽  
Vol 713-715 ◽  
pp. 2989-2992
Author(s):  
Xue Kui Wang ◽  
Ying Zhou ◽  
Ling Li ◽  
Tian Cheng Gao ◽  
Na Tang
Keyword(s):  
Neural Network ◽  
Experimental Data ◽  
Artificial Neural Network ◽  
Relative Humidity ◽  
Evaporation Rate ◽  
Evaporation Model ◽  
Irradiation Intensity ◽  
Artificial Neural ◽  
Good Agreement

The influence of natural evaporation factors (the irradiation intensity, speed of the wind, temperature of the brine, temperature and relative humidity of the air) on the desalinated seawater evaporation rate was measured experimentally. A natural evaporation model was built by correlating the experimental data using the artificial neural network. This model was well correlated with the influence of natural evaporation factors, and it showed a good agreement of the results and evaporation theory.

scholarly journals Strangeness at high μB: Recent data from FOPI and HADES

2018 ◽  
Vol 171 ◽  
pp. 02001
Author(s):  
Yvonne Leifels
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Particle Production ◽  
Chemical Potential ◽  
Good Description ◽  
Branching Ratio ◽  
Heavy Ion ◽  
Nuclear Medium ◽  
Strangeness Production ◽  
Baryon Chemical Potential

Strangeness production in heavy-ion reactions at incident energies at or below the threshold in NN collisions gives access to the characteristics of bulk nuclear matter and the properties of strange particles inside the hot and dense nuclear medium, like potentials and interaction cross sections. At these energies strangeness is produced in multi-step processes potentially via excitation of intermediate heavy resonances. The amount of experimental data on strangeness production at these energies has increased substantially during the last years due to the FOPI and the HADES experiments at SIS18 at GSI. Experimental data on K+ and K0 production support the assumption that particles with an s quark feel a moderate repulsive potential in the nuclear medium. The situation is not that clear in the case of K-. Here, spectra and flow of K- mesons is influenced by the contribution of ø mesons which are decaying into K+K- pairs with a branching ratio of 48.9 %. Depending on incident energy upto 30 % of all K- mesons measured in heavyion collisions are originating from ø-decays. Strangeness production yields - except the yield of Ξ- are described by thermal hadronisation models. Experimental data not only measured for heavy-ion collisions but also in proton induced reactions are described with sets of temperature T and baryon chemical potential μb which are close to a universal freeze-out curve which is fitting also experimental data obtained at lower baryon chemical potential. Despite the good description of most particle production yields, the question how this is achieved is still not settled and should be the focus of further investigations.

scholarly journals Clouds Over Soot Evaporation: Errors in Modeling Laser-Induced Incandescence of Soot

2000 ◽  
Vol 123 (4) ◽  
pp. 814-818 ◽  
Author(s):  
G. J. Smallwood ◽  
D. R. Snelling ◽  
F. Liu ◽  
O¨. L. Gu¨lder
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Evaporation Process ◽  
Thermal Velocity ◽  
Carbon Vapor ◽  
Evaporation Model ◽  
Correct Formulation ◽  
Intense Evaporation ◽  
Laser Induced Incandescence ◽  
Heat Of Evaporation

The ambiguity and incorrect treatment of the evaporation term among some LII models in the literature are discussed. This study does not suggest that the correct formulation presented for the evaporation model is adequate, or that it reflects the soot evaporation process under intense evaporation. The emphasis is that the current evaporation model must be used correctly in the evaluation of the LII model against experimental data. Numerical results are presented to demonstrate the significance of the molecular weight associated with the heat of evaporation and the thermal velocity of carbon vapor on the results obtained with the evaporation model. Other errors frequently repeated in the literature are also identified.

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