scholarly journals New method for calculating electromagnetic effects in semileptonic beta-decays of mesons

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Chien-Yeah Seng ◽  
Xu Feng ◽  
Mikhail Gorchtein ◽  
Lu-Chang Jin ◽  
Ulf-G. Meißner
Keyword(s):  
Perturbation Theory ◽  
Lattice Qcd ◽  
Beta Decay ◽  
Chiral Perturbation Theory ◽  
Low Energy ◽  
Matrix Elements ◽  
Chiral Perturbation ◽  
Electromagnetic Effects ◽  
Beta Decays ◽  
Energy Constants

Abstract We construct several classes of hadronic matrix elements and relate them to the low-energy constants in Chiral Perturbation Theory that describe the electromagnetic effects in the semileptonic beta decay of the pion and the kaon. We propose to calculate them using lattice QCD, and argue that such a calculation will make an immediate impact to a number of interesting topics at the precision frontier, including the outstanding anomalies in |Vus| and the top-row Cabibbo-Kobayashi-Maskawa matrix unitarity.

scholarly journals New method for fitting the low-energy constants in chiral perturbation theory

2020 ◽  
Vol 102 (9) ◽  
Author(s):  
Qin-He Yang ◽  
Wei Guo ◽  
Feng-Jun Ge ◽  
Bo Huang ◽  
Hao Liu ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Low Energy ◽  
New Method ◽  
Chiral Perturbation ◽  
Energy Constants

scholarly journals Chiral Perturbation Theory vs. Linear Sigma Model in A Chiral Imbalance Medium

2019 ◽  
Author(s):  
Alexander Andrianov ◽  
Vladimir Andrianov ◽  
Domenec Espriu
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Sigma Model ◽  
Decay Constant ◽  
Charged Pion ◽  
Low Energy ◽  
Linear Sigma Model ◽  
Chiral Perturbation ◽  
Energy Constants ◽  
Parity Breaking

We compare Chiral Perturbation Theory (ChPT) and the Linear Sigma Model (LSM) as realizations of low energy QCD for light mesons in a chirally imbalanced medium. The relations between the low-energy constants of the Chiral Lagrangian and the corresponding constants of the Linear Sigma Model are established as well as the expressions for the decay constant of $\pi $-meson in the medium and for the mass of the $a_0$. In the large $N_c$ count taken from QCD the correspondence of ChPT and LSM is remarkably good and give a solid ground for search of chiral imbalance manifestation in pion physics. A possible experimental detection of chiral imbalance (and therefore a phase with Local Parity Breaking) is outlined in the charged pion decays inside the fireball.

scholarly journals SU(2) chiral perturbation theory low-energy constants from2+1flavor staggered lattice simulations

2013 ◽  
Vol 88 (1) ◽  
Author(s):  
Szabolcs Borsányi ◽  
Stephan Dürr ◽  
Zoltán Fodor ◽  
Stefan Krieg ◽  
Andreas Schäfer ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Low Energy ◽  
Chiral Perturbation ◽  
Energy Constants

scholarly journals LOW-ENERGY CONSTANTS AND CONDENSATES FROM THE V – A SPECTRUM

2014 ◽  
Vol 35 ◽  
pp. 1460443
Author(s):  
DIOGO BOITO ◽  
MAARTEN GOLTERMAN ◽  
MATTHIAS JAMIN ◽  
KIM MALTMAN ◽  
SANTIAGO PERIS
Keyword(s):  
Perturbation Theory ◽  
Spectral Data ◽  
Chiral Perturbation Theory ◽  
Low Energy ◽  
Chiral Perturbation ◽  
Energy Constants

We present an analysis of the isospin-one V – A correlator based on our successful simultaneous description of the OPAL V and A non-strange tau spectral data. We discuss the values obtained for the Chiral Perturbation Theory low-energy constants L10 and C87 as well as the dimension-six and eight condensates and compare them with those in the literature.

scholarly journals The role of isospin filtering reactions in the S = −1 sector

2019 ◽  
Vol 199 ◽  
pp. 03008
Author(s):  
A. Feijoo ◽  
V.K. Magas ◽  
A. Ramos
Keyword(s):  
Perturbation Theory ◽  
High Spin ◽  
Chiral Perturbation Theory ◽  
Low Energy ◽  
Scattering Data ◽  
Leading Order ◽  
Chiral Perturbation ◽  
Effective Lagrangian ◽  
Energy Constants

The present study reveals interesting constraining effects of isospin filtering reactions on the low energy constants present in meson-baryon chiral effective Lagrangian, particularly, on the next-to-leading order constants. Our model has been developed within the framework of Unitarized Chiral Perturbation Theory and has been fitted to two-body scattering data in the sector of S = −1. In addition, the model was further elaborated by means of the inclusion of high-spin hyperonic resonances.

Lowest-lying octet baryon masses up to $\mathcal{O}(p^4)$ in covariant baryon chiral perturbation theory

2014 ◽  
Vol 29 ◽  
pp. 1460215
Author(s):  
Xiu-Lei Ren ◽  
Lisheng Geng ◽  
Jie Meng ◽  
Hiroshi Toki
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Mass Shell ◽  
Renormalization Scheme ◽  
Low Energy ◽  
Tree Level ◽  
Chiral Perturbation ◽  
Octet Baryon ◽  
Reasonable Description ◽  
Energy Constants

In this talk, we report on a systematic study of the lowest-lying octet baryon masses in covariant baryon chiral perturbation theory with the extended-on-mass-shell renormalization scheme up to [Formula: see text]. By adjusting the low-energy constants, a reasonable description of the nf = 2 + 1 lattice results is achieved with χ2/d.o.f. about 1. It confirms that the various lattice simulations are consistent with each other. We also find that the virtual decuplet effects on the baryon masses cannot be disentangled from those of the virtual octet baryons and the tree level diagrams.

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