scholarly journals PION PROPERTIES AT FINITE DENSITY

2009 ◽  
Vol 24 (11n13) ◽  
pp. 891-894
Author(s):  
SEUNG-IL NAM ◽  
HYUN-CHUL KIM
Keyword(s):  
Quark Model ◽  
Recent Work ◽  
Decay Constant ◽  
Chemical Potential ◽  
Lorentz Invariance ◽  
Pion Mass ◽  
Weak Decay ◽  
Chiral Quark Model ◽  
Time And Space ◽  
Finite Density

In this talk, we report our recent work on the pion weak decay constant (Fπ) and pion mass (mπ) using the nonlocal chiral quark model with the finite quark-number chemical potential (μ) taken into account. Considering the breakdown of Lorentz invariance at finite density, the time and space components are computed separately, and the corresponding results turn out to be: [Formula: see text] and [Formula: see text] at μc ≈ 320 MeV , respectively. Using the in-medium Gell-Mann-Oakes-Renner (GOR) relation, we show that the pion mass increases by about 15% at μc.

scholarly journals Pion weak decay constant at finite density from the instanton vacuum

2008 ◽  
Vol 666 (4) ◽  
pp. 324-331 ◽  
Author(s):  
Seung-il Nam ◽  
Hyun-Chul Kim
Keyword(s):  
Decay Constant ◽  
Weak Decay ◽  
Finite Density ◽  
Instanton Vacuum

scholarly journals HEAVY PSEUDOSCALAR-MESON DECAY CONSTANTS WITH STRANGENESS FROM THE EXTENDED NONLOCAL CHIRAL-QUARK MODEL

2012 ◽  
Vol 27 (27) ◽  
pp. 1250153 ◽  
Author(s):  
SEUNG-IL NAM
Keyword(s):  
Heavy Quark ◽  
Quark Model ◽  
Weak Decay ◽  
Heavy Meson ◽  
Effective Field ◽  
Numerical Results ◽  
Meson Decay ◽  
Chiral Quark Model ◽  
Decay Constants ◽  
Pseudoscalar Mesons

We study the weak-decay constants for the heavy pseudoscalar mesons, D, Ds, B and Bs. For this purpose, we employ the extended nonlocal chiral-quark model (ExNLChQM), motivated by the heavy-quark effective field theory as well as the instanton-vacuum configuration. In addition to the heavy-quark symmetry and the nonlocal interactions between quarks and pseudoscalar mesons in ExNLChQM, a correction for the strange-quark content inside Ds and Bs is also taken into account and found to be crucial to reproduce the empirical values. From those numerical results, we obtain fD, Ds, B, Bs = (207.53, 262.56, 208.13, 262.39) MeV , which are in good agreement with experimental data and other theoretical estimations. Using those numerical results, we estimate the CKM matrix elements and the Cabibbo angle with the various mesonic and leptonic heavy-meson decay channels, resulting in (|Vcd|, |Vcs|, |Vub|, |Vtd|/|Vts|) = (0.224, 0.968, <5.395×10-3, 0.215) and θC = 12.36° which are well compatible with available data.

scholarly journals $\Sigma_c {\bar D}$ AND $\Lambda_c {\bar D}$ STATES IN A CHIRAL QUARK MODEL

2014 ◽  
Vol 26 ◽  
pp. 1460071
Author(s):  
W. L. WANG ◽  
F. HUANG ◽  
Z. Y. ZHANG ◽  
B. S. ZOU
Keyword(s):  
Binding Energy ◽  
Quark Model ◽  
Recent Work ◽  
Bound State ◽  
Repulsive Interaction ◽  
Chiral Quark Model ◽  
Text Interaction

We report our recent work on a dynamical investigation of the [Formula: see text] and [Formula: see text] states in a chiral quark model. Our results show that the [Formula: see text] interaction is attractive, which consequently results in a [Formula: see text] bound state with the binding energy of about 5-42 MeV, unlike the case of [Formula: see text] state, which has a repulsive interaction and thus is unbound.

scholarly journals Cold magnetized quark matter at finite density in a nonlocal chiral quark model

2021 ◽  
Vol 57 (4) ◽  
Author(s):  
S. A. Ferraris ◽  
D. Gómez Dumm ◽  
A. G. Grunfeld ◽  
N. N. Scoccola
Keyword(s):  
Quark Model ◽  
Quark Matter ◽  
Chiral Quark Model ◽  
Finite Density

scholarly journals sQq¯q¯ ( q=u , d ; Q=c , b ) tetraquarks in the chiral quark model

2021 ◽  
Vol 103 (7) ◽  
Author(s):  
Gang Yang ◽  
Jialun Ping ◽  
Jorge Segovia
Keyword(s):  
Quark Model ◽  
Chiral Quark Model

scholarly journals The Genuine Resonance of Full-Charm Tetraquarks

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 155
Author(s):  
Xiaoyun Chen
Keyword(s):  
Quark Model ◽  
Bound States ◽  
Expansion Method ◽  
Chiral Quark Model ◽  
Stabilization Method ◽  
Scaling Method ◽  
Resonance States ◽  
Gaussian Expansion Method ◽  
Color Structure ◽  
Quantum Numbers

In this work, the genuine resonance states of full-charm tetraquark systems with quantum numbers JPC=0++,1+−,2++ are searched in a nonrelativistic chiral quark model with the help of the Gaussian Expansion Method. In this calculation, two structures, meson-meson and diquark–antidiquark, as well as their mixing with all possible color-spin configurations, are considered. The results show that no bound states can be formed. However, resonances are possible because of the color structure. The genuine resonances are identified by the stabilization method (real scaling method). Several resonances for the full-charm system are proposed, and some of them are reasonable candidates for the full-charm states recently reported by LHCb.

scholarly journals Complex Langevin calculations in QCD at finite density

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Yuta Ito ◽  
Hideo Matsufuru ◽  
Yusuke Namekawa ◽  
Jun Nishimura ◽  
Shinji Shimasaki ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Chemical Potential ◽  
Expansion Method ◽  
Finite Density ◽  
Fermi Sphere ◽  
Expectation Value ◽  
Sign Problem ◽  
Zero Momentum ◽  
Effective Theories ◽  
Severe Sign

Abstract We demonstrate that the complex Langevin method (CLM) enables calculations in QCD at finite density in a parameter regime in which conventional methods, such as the density of states method and the Taylor expansion method, are not applicable due to the severe sign problem. Here we use the plaquette gauge action with β = 5.7 and four-flavor staggered fermions with degenerate quark mass ma = 0.01 and nonzero quark chemical potential μ. We confirm that a sufficient condition for correct convergence is satisfied for μ/T = 5.2 − 7.2 on a 83 × 16 lattice and μ/T = 1.6 − 9.6 on a 163 × 32 lattice. In particular, the expectation value of the quark number is found to have a plateau with respect to μ with the height of 24 for both lattices. This plateau can be understood from the Fermi distribution of quarks, and its height coincides with the degrees of freedom of a single quark with zero momentum, which is 3 (color) × 4 (flavor) × 2 (spin) = 24. Our results may be viewed as the first step towards the formation of the Fermi sphere, which plays a crucial role in color superconductivity conjectured from effective theories.

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