scholarly journals $$a_{1}$$ meson-nucleon coupling constant at finite temperature from the soft-wall AdS/QCD model

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
Shahin Mamedov ◽  
Shahnaz Taghiyeva

AbstractWe study the temperature dependence of the $$a_1$$ a 1 meson-nucleon coupling constant in the framework of the soft-wall AdS/QCD model with thermal dilaton field. Profile functions for the axial-vector and fermion fields in the AdS-Schwarzschild metric are presented. It is constructed an interaction Lagrangian for the fermion-axial-vector-thermal dilaton fields system in the bulk of space-time. From this Lagrangian integral representation for the $$g_{a_1NN}$$ g a 1 N N coupling constant is derived. The temperature dependence of this coupling constant is numerically analyzed.

2019 ◽  
Vol 34 (35) ◽  
pp. 1950240 ◽  
Author(s):  
Narmin Huseynova ◽  
Shahin Mamedov

We calculate the [Formula: see text]-meson-nucleon ([Formula: see text]-baryon) coupling constant in the framework of soft-wall and hard-wall AdS/QCD models. Interaction Lagrangian in the bulk of AdS space was written for a minimal gauge coupling, a magnetic type coupling and a triple coupling of bulk fields. Applying AdS/CFT correspondence from the bulk interaction Lagrangian, we obtain holographic expressions for the [Formula: see text]-axial-vector meson-nucleon ([Formula: see text]-baryon) coupling constant in the boundary QCD theory. Numerical results for the [Formula: see text] coupling constant in the framework of both models are close to the known phenomenological estimates. The [Formula: see text]-axial-vector meson-[Formula: see text]-baryon coupling constant was considered in the framework of hard-wall model.


2017 ◽  
Vol 2017 ◽  
pp. 1-24 ◽  
Author(s):  
Alejandro Ayala ◽  
C. A. Dominguez ◽  
M. Loewe

The method of QCD sum rules at finite temperature is reviewed, with emphasis on recent results. These include predictions for the survival of charmonium and bottonium states, at and beyond the critical temperature for deconfinement, as later confirmed by lattice QCD simulations. Also included are determinations in the light-quark vector and axial-vector channels, allowing analysing the Weinberg sum rules and predicting the dimuon spectrum in heavy-ion collisions in the region of the rho-meson. Also, in this sector, the determination of the temperature behaviour of the up-down quark mass, together with the pion decay constant, will be described. Finally, an extension of the QCD sum rule method to incorporate finite baryon chemical potential is reviewed.


2005 ◽  
Vol 127 (4) ◽  
pp. 408-416 ◽  
Author(s):  
H. Jiang ◽  
Y. Huang ◽  
K. C. Hwang

There are significant efforts to develop continuum theories based on atomistic models. These atomistic-based continuum theories are limited to zero temperature (T=0K). We have developed a finite-temperature continuum theory based on interatomic potentials. The effect of finite temperature is accounted for via the local harmonic approximation, which relates the entropy to the vibration frequencies of the system, and the latter are determined from the interatomic potential. The focus of this theory is to establish the continuum constitutive model in terms of the interatomic potential and temperature. We have studied the temperature dependence of specific heat and coefficient of thermal expansion of graphene and diamond, and have found good agreements with the experimental data without any parameter fitting. We have also studied the temperature dependence of Young’s modulus and bifurcation strain of single-wall carbon nanotubes.


2019 ◽  
Vol 34 (12) ◽  
pp. 1950061
Author(s):  
M. Butler ◽  
A. M. Ghezelbash

We present novel classes of nonstationary solutions to the five-dimensional generalized Einstein–Maxwell-dilaton theory with cosmological constant, in which the Maxwell’s field and the cosmological constant couple to the dilaton field. In the first class of solutions, the two nonzero coupling constants are different, while in the second class of solutions, the two coupling constants are equal to each other. We find consistent cosmological solutions with positive, negative or zero cosmological constant, where the cosmological constant depends on the value of one coupling constant in the theory. Moreover, we discuss the physical properties of the five-dimensional solutions and the uniqueness of the solutions in five dimensions by showing the solutions with different coupling constants cannot be uplifted to any Einstein–Maxwell theory in higher dimensions.


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