scholarly journals 2S and 3S State Masses and decay constants of heavy-flavour mesons in a non-relativistic QCD potential model with three-loop effects in V-scheme

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Rashidul Hoque ◽  
B. J. Hazarika ◽  
D. K. Choudhury
Keyword(s):  
Perturbation Theory ◽  
Strong Coupling ◽  
Potential Model ◽  
Dynamic Properties ◽  
Strong Coupling Constant ◽  
Coupling Constant ◽  
Decay Constants ◽  
Scalar Mesons ◽  
Experimental Values ◽  
Pseudo Scalar

AbstractWe make an analysis of three -loop effects of the strong coupling constant in the study of masses and decay constants of the heavy-flavour pseudo-scalar mesons (PSM) D, $$D_s$$ D s , B, $$B_s,$$ B s , $$B_c$$ B c , $$\eta _c$$ η c and $$\eta _b$$ η b in a non-relativistic QCD potential model using Dalgarno’s perturbation theory (DPT). The first order mesonic wavefunction is obtained using Dalgarno’s perturbation theory. The three-loop effects of strong coupling constant are included in the wave function in co-ordinate space and then used to examine the static and dynamic properties of the heavy-flavour mesons for 2S and 3S higher states. The results are compared with the other models available and are found to be compatible with available experimental values. In V-scheme, the three-loop effects on masses and decay constants of heavy-flavour mesons show a significant result.

scholarly journals On next to soft threshold corrections to DIS and SIA processes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
A. H. Ajjath ◽  
Pooja Mukherjee ◽  
V. Ravindran ◽  
Aparna Sankar ◽  
Surabhi Tiwari
Keyword(s):  
Perturbation Theory ◽  
Inelastic Scattering ◽  
Deep Inelastic Scattering ◽  
Strong Coupling ◽  
Cross Sections ◽  
Strong Coupling Constant ◽  
Renormalisation Group ◽  
Coupling Constant ◽  
Parton Level ◽  
Soft Threshold

Abstract We study the perturbative structure of threshold enhanced logarithms in the coefficient functions of deep inelastic scattering (DIS) and semi-inclusive e+e− annihilation (SIA) processes and setup a framework to sum them up to all orders in perturbation theory. Threshold logarithms show up as the distributions ((1−z)−1 logi(1−z))+ from the soft plus virtual (SV) and as logarithms logi(1−z) from next to SV (NSV) contributions. We use the Sudakov differential and the renormalisation group equations along with the factorisation properties of parton level cross sections to obtain the resummed result which predicts SV as well as next to SV contributions to all orders in strong coupling constant. In Mellin N space, we resum the large logarithms of the form logi(N) keeping 1/N corrections. In particular, the towers of logarithms, each of the form $$ {a}_s^n/{N}^{\alpha }{\log}^{2n-\alpha }(N),{a}_s^n/{N}^{\alpha }{\log}^{2n-1-\alpha }(N)\cdots $$ a s n / N α log 2 n − α N , a s n / N α log 2 n − 1 − α N ⋯ etc for α = 0, 1, are summed to all orders in as.

On the bounds of CKM matrix element Vcb in a potential model

2014 ◽  
Vol 29 (11n12) ◽  
pp. 1450066 ◽  
Author(s):  
D. K. Choudhury ◽  
Krishna Kingkar Pathak
Keyword(s):  
Matrix Element ◽  
Strong Coupling ◽  
Potential Model ◽  
B Meson ◽  
Scale Parameter ◽  
Strong Coupling Constant ◽  
Coupling Constant ◽  
Ckm Matrix

Considering the allowed range of slope ρ2 and curvature C of Isgur–Wise function for B meson, we obtain an allowed range of strong coupling constant αs as well as the QCD scale parameter Λ in a specific prescription. The allowed range of Λ is then used to obtain the theoretical bounds on Vcb in a potential model. The recent available data of Vcb are found to lie within this computed range 0.0375 ≤|Vcb|≤0.0410.

scholarly journals Low energy determination of the QCD strong coupling constant on the lattice

2016 ◽  
Vol 31 (30) ◽  
pp. 1630033
Author(s):  
Yu Maezawa ◽  
Peter Petreczky
Keyword(s):  
Strong Coupling ◽  
Strong Coupling Constant ◽  
Low Energy ◽  
Coupling Constant ◽  
Lattice Quantum Chromodynamics ◽  
A Value ◽  
Lattice Quantum ◽  
Pseudo Scalar ◽  
Energy Determination

We present a determination of the strong coupling constant from lattice quantum chromodynamics (QCD) using the moments of pseudo-scalar charmonium correlators calculated using highly improved staggered quark action. We obtain a value [Formula: see text], which is the lowest energy determination of the strong coupling constant so far.

scholarly journals EMC effect at small Bjorken x values

2019 ◽  
Vol 204 ◽  
pp. 05002
Author(s):  
A. Kotikov ◽  
B. Shaikhatdenov ◽  
P. Zhang
Keyword(s):  
Strong Coupling ◽  
Gluon Density ◽  
Strong Coupling Constant ◽  
Coupling Constant ◽  
Emc Effect ◽  
Bjorken X

The Bessel-inspired behavior of parton densities at small Bjorken x values is used along with “frozen” and analytic modifications of the strong coupling constant [1] to study the so-called EMC effect. Among other results, this approach allowed predicting small x behavior of the gluon density in nuclei.

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