scholarly journals Two-body decay widths of lowest lying and next-to-lowest lying scalar and pseudoscalar mesons in generalized linear sigma model

2015 ◽  
Vol 30 (22) ◽  
pp. 1550134 ◽  
Author(s):  
S. Mohammad Zebarjad ◽  
Soodeh Zarepour

Two-body decay widths of lowest lying and next-to-lowest lying scalar and pseudoscalar mesons are studied in generalized linear sigma model (GLSM) of low-energy QCD. This model which considers mixing between “two-quark” and “four-quark” chiral nonets has been employed to investigate various decays and scatterings in low-energy region of QCD. In this paper, [Formula: see text] and [Formula: see text] are obtained and it is shown that two-body decay widths of lowest lying mesons are well predicted by this model while for the next-to-lowest lying mesons, only some of the decay widths agree with the experimental results. We have compared the predicted decay widths in GLSM with the results obtained in single nonet linear sigma model (SNLSM) to indicate that chiral nonet mixing greatly improves the predictions of SNLSM for decay widths.

2011 ◽  
Vol 26 (14) ◽  
pp. 2327-2352 ◽  
Author(s):  
AMIR H. FARIBORZ

A procedure for implementation of the generating equations in the linear sigma model of low energy QCD is presented. For any explicit symmetry breaking term, this procedure computes the masses of scalar and pseudoscalar mesons as well as various three-point and four-point interaction vertices that are needed in calculation of different decay widths and scattering amplitudes.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Yuki Hiraga ◽  
Yuki Sato

Abstract We study quantum aspects of the target space of the non-linear sigma model, which is a low-energy effective theory of the gauged linear sigma model (GLSM). As such, we especially compute the exact sphere partition function of the GLSM for KK$5$-branes whose background geometry is a Taub–NUT space, using the supersymmetric localization technique on the Coulomb branch. From the sphere partition function, we distill the world-sheet instanton effects. In particular, we show that, concerning the single-centered Taub–NUT space, instanton contributions exist only if the asymptotic radius of the $S^1$ fiber in the Taub–NUT space is zero.


2016 ◽  
Author(s):  
Thomas Kloiber ◽  
Falk Bruckmann ◽  
Christof Gattringer ◽  
Tin Sulejmanpasic

Author(s):  
Alexander Andrianov ◽  
Vladimir Andrianov ◽  
Domenec Espriu

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.


2019 ◽  
Vol 34 (06n07) ◽  
pp. 1950034
Author(s):  
Amir H. Fariborz ◽  
Renata Jora ◽  
Maria Lyukova

Within the framework of the generalized linear sigma model with glueballs recently proposed,[Formula: see text] we study the schematic spectroscopy of scalar and pseudoscalar mesons in the SU(3) flavor limit and explore their quark and glue contents. In this framework, for both scalars and pseudoscalars, the two octet physical states are admixtures of quark–antiquark and four-quark components, and the three singlet states contain quark–antiquark, four-quark and glue components. We identify the two scalar octets with [Formula: see text] and [Formula: see text] and the two pseudoscalar octets with [Formula: see text] and [Formula: see text]. We show that, as expected, the light pseudoscalar octet is made dominantly of quark–antiquarks whereas the light scalar octet has a reversed substructure with a dominant four-quark component. The case of singlets is more complex due to surplus of states up to around 2 GeV. We consider all 35 permutations for identifying the three pseudoscalar singlets of our model with three of the seven experimental candidates. Our numerical simulation unambiguously identifies the lightest and the heaviest pseudoscalar singlets with [Formula: see text] and [Formula: see text], respectively, and favors the identification of the middle singlet with either [Formula: see text] or [Formula: see text] (or, to a lesser extent, with [Formula: see text]) and thereby allows a probe of their substructures. We then estimate the quark and glue components and find that the three pseudoscalar singlets (from lightest to heaviest) are mainly of quark–antiquark, four-quark and glue substructure, while the corresponding three scalar singlets (from lightest to heaviest) are of four-quark, quark–antiquark and glue contents. The masses of pure pseudoscalar and scalar glueballs are estimated around 2.0 and 1.6 GeV, respectively.


1991 ◽  
Vol 86 (3) ◽  
pp. 265-269
Author(s):  
M. K. Volkov ◽  
A. A. Osipov

Particles ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Alexander Andrianov ◽  
Vladimir Andrianov ◽  
Domenec Espriu

We compare the chiral perturbation theory (ChPT) and the linear sigma model (LSM) as realizations of low energy quantum chromodynamics (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 π -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 provides a solid ground for the search of chiral imbalance manifestations 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.


1989 ◽  
Vol 04 (19) ◽  
pp. 1815-1825
Author(s):  
I.V. ANDREEV ◽  
M.M. TSYPIN

The effective Lagrangian for pseudoscalar meson octet including terms up to fourth order in momenta and masses is derived from a linear sigma model with vector and axial mesons. The mass of scalar meson nonet 720±75 MeV ensures a good fit of coefficients in effective Lagrangian with values derived from experiment.


2018 ◽  
Vol 54 (1) ◽  
Author(s):  
Florian Divotgey ◽  
Peter Kovacs ◽  
Francesco Giacosa ◽  
Dirk H. Rischke

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