$N_f$ dependence of the quark condensate from a chiral sum rule

2000 ◽  
Vol 14 (1) ◽  
pp. 111-122 ◽  
Author(s):  
B. Moussallam
Keyword(s):  
Quark Condensate ◽  
Sum Rule

scholarly journals GENERAL FORMULA FOR THE FOUR-QUARK CONDENSATE AND VACUUM FACTORIZATION ASSUMPTION

2008 ◽  
Vol 23 (10) ◽  
pp. 1507-1520 ◽  
Author(s):  
HONG-SHI ZONG ◽  
DENG-KE HE ◽  
FENG-YAO HOU ◽  
WEI-MIN SUN
Keyword(s):  
General Formula ◽  
Linear Response ◽  
Chemical Potential ◽  
Background Field ◽  
Quark Propagator ◽  
Quark Condensate ◽  
Sum Rule ◽  
Factorization Problem ◽  
Field Approach ◽  
General Method

By differentiating the dressed quark propagator with respect to a variable background field, the linear response of the dressed quark propagator in the presence of the background field can be obtained. From this general method, using the vector background field as an illustration, we derive a general formula for the four-quark condensate [Formula: see text]. This formula contains the corresponding fully dressed vector vertex and it is shown that factorization for [Formula: see text] holds only when the dressed vertex is taken to be the bare one. This property also holds for all other types of four-quark condensate. By comparing this formula with the general expression for the corresponding vacuum susceptibility, it is found that there exists some intrinsic relation between these two quantities, which are usually treated as independent phenomenological inputs in the QCD sum rule external field approach. The above results are also generalized to the case of finite chemical potential and the factorization problem of the four-quark condensate at finite chemical potential is discussed.

scholarly journals Inverse moment of the Bs-meson distribution amplitude from QCD sum rule

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Alexander Khodjamirian ◽  
Rusa Mandal ◽  
Thomas Mannel
Keyword(s):  
Light Cone ◽  
Quark Mass ◽  
Strange Quark ◽  
Quark Condensate ◽  
Distribution Amplitude ◽  
Symmetry Violation ◽  
Sum Rule ◽  
Strange Quark Mass ◽  
The Difference ◽  
Inverse Moment

Abstract We derive a QCD sum rule for the inverse moment of the Bs-meson light-cone distribution amplitude in HQET. Within this method, the SU(3)f l symmetry violation is traced to the strange quark mass and to the difference between strange and nonstrange quark condensate densities. We predict the ratio of inverse moments λBs/λB = 1.19 ± 0.14 which can be used in various applications of these distribution amplitudes to the analyses of Bs-meson decays, provided an accurate value of λB is available from other sources, such as the B → ℓνℓγ decay.

NEW INSIGHTS ON VECTOR MESONS: A DIALOG BETWEEN $f^{T}_{V}$ AND fV

2008 ◽  
Vol 23 (21) ◽  
pp. 3209-3212
Author(s):  
OSCAR CATÀ
Keyword(s):  
Magnetic Susceptibility ◽  
Excellent Agreement ◽  
High Energy ◽  
Quark Condensate ◽  
Vector Mesons ◽  
Meson Resonance ◽  
Sum Rule ◽  
High Energy Behavior ◽  
Energy Behavior ◽  
Hadronic Model

We examine the high energy behavior of the two-point correlators 〈VV〉, 〈TT〉, 〈VT〉 and its implications on the spectrum of spin-1 vector mesons. This leads to an estimate of [Formula: see text] in excellent agreement with the recent sum rule and lattice determinations. This information is later implemented in a hadronic model and used to estimate the value of the magnetic susceptibility of the quark condensate χ0. Our analysis shows that lowest meson resonance may turn out to be a bad approximation for this quantity.

scholarly journals Cwebs beyond three loops in multiparton amplitudes

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Neelima Agarwal ◽  
Lorenzo Magnea ◽  
Sourav Pal ◽  
Anurag Tripathi
Keyword(s):  
Gauge Theories ◽  
Anomalous Dimension ◽  
Wilson Line ◽  
Building Blocks ◽  
Feynman Diagrams ◽  
Loop Order ◽  
Abelian Gauge ◽  
Sum Rule ◽  
Combinatorial Properties ◽  
Low Dimensional

Abstract Correlators of Wilson-line operators in non-abelian gauge theories are known to exponentiate, and their logarithms can be organised in terms of collections of Feynman diagrams called webs. In [1] we introduced the concept of Cweb, or correlator web, which is a set of skeleton diagrams built with connected gluon correlators, and we computed the mixing matrices for all Cwebs connecting four or five Wilson lines at four loops. Here we complete the evaluation of four-loop mixing matrices, presenting the results for all Cwebs connecting two and three Wilson lines. We observe that the conjuctured column sum rule is obeyed by all the mixing matrices that appear at four-loops. We also show how low-dimensional mixing matrices can be uniquely determined from their known combinatorial properties, and provide some all-order results for selected classes of mixing matrices. Our results complete the required colour building blocks for the calculation of the soft anomalous dimension matrix at four-loop order.

Raman sum rule and the relation to the infrared sum rule in La2-xSrxCuO4

2010 ◽  
Vol 470 ◽  
pp. S97-S98 ◽  
Author(s):  
S. Sugai ◽  
Y. Takayanagi ◽  
N. Hayamizu ◽  
T. Muroi ◽  
J. Nohara ◽  
...  
Keyword(s):  
Sum Rule

A new isotopic sum rule

1978 ◽  
Vol 73 (3) ◽  
pp. 503-504 ◽  
Author(s):  
P. Babu Rao ◽  
K.V. Siva Sarma ◽  
K. SreeRamamurty
Keyword(s):  
Sum Rule

scholarly journals Quantitative sum rule analysis of low-temperature spectral functions

2013 ◽  
Vol 87 (7) ◽  
Author(s):  
Nathan P. M. Holt ◽  
Paul M. Hohler ◽  
Ralf Rapp
Keyword(s):  
Low Temperature ◽  
Spectral Functions ◽  
Sum Rule ◽  
Rule Analysis
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