scholarly journals Radially excited axial-vector mesons in the extended Nambu–Jona-Lasinio model

2014 ◽  
Vol 29 (24) ◽  
pp. 1450125 ◽  
Author(s):  
A. V. Vishneva ◽  
M. K. Volkov
Keyword(s):  
Experimental Data ◽  
Excited State ◽  
Mass Spectrum ◽  
Excited States ◽  
Axial Vector ◽  
Form Factors ◽  
Radiative Decays ◽  
Vector Mesons ◽  
Polynomial Type ◽  
Quark Momentum

The first radial excitations of axial-vector mesons are considered in the framework of the extended U(3) × U(3) Nambu–Jona-Lasinio model. We calculate the mass spectrum of a1, f1 and also strange axial-vector mesons. For description of radially excited states, we used the form factors of polynomial type of the second order in transverse quark momentum. For the ground- and excited-state mesons consisting of light quarks we have calculated the widths of a number of strong and radiative decays. We got satisfactory agreement with experimental data for the ground states. A set of predictions for the excited states of mesons is given.

scholarly journals The interplay of transverse degrees of freedom and axial-vector mesons with short-distance constraints in g−2

2021 ◽  
Author(s):  
Pere Masjuan ◽  
Pablo Roig ◽  
Pablo Sanchez Puertas
Keyword(s):  
Short Distance ◽  
Degrees Of Freedom ◽  
Axial Vector ◽  
Form Factors ◽  
Experimental Result ◽  
Special Focus ◽  
Vector Mesons ◽  
Distance Constraints ◽  
The Past

Abstract We revisit well-known short-distance constraints relating the hadronic light-by light Green's function to the〈VVA〉one, that have been a subject of debate over the past years in the context of the muon (g-2). Specifically, we identify a relation among the longitudinal and transverse degrees of freedom that is enforced by the axial anomaly that, by contrast, has not received attention in the past. Such relation allows, among other things, to overcome the problem of basis ambiguities when describing axial-vector mesons transition form factors, but further applications are discussed as well, with special focus on the role of axial-vector mesons in the HLbL contribution to the muon (g-2). Our results should also contribute to a better understanding of the, so far, controversial interplay among short-distance constraints with longitudinal and transverse degrees of freedom, such as axial-vector mesons. This is key to confront the theoretical and experimental result for the muon (g-2) that, currently, exhibits a 4.2σ tension.

scholarly journals Isovector axial form factors of the nucleon in two-flavor lattice QCD

2019 ◽  
Vol 34 (02) ◽  
pp. 1950009 ◽  
Author(s):  
S. Capitani ◽  
M. Della Morte ◽  
D. Djukanovic ◽  
G. M. von Hippel ◽  
J. Hua ◽  
...  
Keyword(s):  
Excited State ◽  
Axial Vector ◽  
Form Factors ◽  
Heavy Baryon ◽  
Axial Current ◽  
Effective Field ◽  
Chiral Effective Field Theory ◽  
Axial Charge ◽  
Systematic Uncertainties ◽  
Axial Form

We present a lattice calculation of the nucleon isovector axial and induced pseudoscalar form factors on the CLS ensembles using [Formula: see text] dynamical flavors of nonperturbatively [Formula: see text]-improved Wilson fermions and an [Formula: see text]-improved axial current together with the pseudoscalar density. Excited-state effects in the extraction of the form factors are treated using a variety of methods, with a detailed discussion of their respective merits. The chiral and continuum extrapolation of the results is performed both using formulae inspired by Heavy Baryon Chiral Perturbation Theory (HBChPT) and a global approach to the form factors based on a chiral effective field theory (EFT) including axial vector mesons. Our results indicate that careful treatment of excited-state effects is important in order to obtain reliable results for the axial form factors of the nucleon, and that the main remaining error stems from the systematic uncertainties of the chiral extrapolation. As final results, we quote [Formula: see text], [Formula: see text], and [Formula: see text] for the axial charge, axial charge radius and induced pseudoscalar charge, respectively, where the first error is statistical and the second is systematic.

On The Mass Spectrum of Elementary Particles

2021 ◽  
Vol 4 (1) ◽  
Keyword(s):  
Excited State ◽  
Mass Spectrum ◽  
Cosmic Rays ◽  
Excited States ◽  
Magnetic Moments ◽  
Elementary Particles ◽  
Fractional Charge

In the 50s of the last century, M.I. Danysh and J. Pniewski discovered the existence of hypernuclei. In them under the action of cosmic rays, one of nucleons was turned into an excited state. In this paper, it is shown that masses and magnetic moments of such excitations coincide with properties of some elementary particles. Based on this consent, a number of elementary particles should be considered as excited states of different combinations of electrons, positrons, and protons, rather than as composed from quarks with a fractional charge.

scholarly journals On the radiative decays of light vector and axial-vector mesons

2008 ◽  
Vol 813 (1-2) ◽  
pp. 96-170 ◽  
Author(s):  
M.F.M. Lutz ◽  
S. Leupold
Keyword(s):  
Axial Vector ◽  
Radiative Decays ◽  
Vector Mesons ◽  
Light Vector

scholarly journals Hidden gauge formalism for the radiative decays of axial-vector mesons

2009 ◽  
Vol 79 (1) ◽  
Author(s):  
H. Nagahiro ◽  
L. Roca ◽  
A. Hosaka ◽  
E. Oset
Keyword(s):  
Axial Vector ◽  
Radiative Decays ◽  
Vector Mesons

scholarly journals The decay τ → K∗0(892)K−ντ in the extended NJL model

2020 ◽  
Vol 35 (06) ◽  
pp. 2050035 ◽  
Author(s):  
M. K. Volkov ◽  
A. A. Pivovarov ◽  
K. Nurlan
Keyword(s):  
Experimental Data ◽  
Excited States ◽  
Branching Fraction ◽  
Axial Vector ◽  
Dominant Contribution ◽  
Differential Distribution ◽  
Vector Channel ◽  
Njl Model ◽  
Pseudoscalar Mesons ◽  
Meson Pair

In the extended Nambu–Jona-Lasinio model, the branching fraction of [Formula: see text] is calculated. The contributions from the contact diagram and the diagrams with intermediate axial-vector, vector and pseudoscalar mesons in the ground and first radially excited states are taken into account. It is shown that an axial-vector and vector channel with a contact diagram give a dominant contribution to the branching fraction. The obtained results for the branching fraction [Formula: see text] are in satisfactory agreement with experimental data. A prediction for the differential distribution over the invariant mass of the meson pair [Formula: see text] is given.

High-Temperature Reorientation Of Distortions In The Excited State Of The VGaTeAs Complexes In n-Type GaAs

1996 ◽  
Vol 442 ◽  
Author(s):  
A. A. Gutkin ◽  
M. A. Reshchikov ◽  
V. E. Sedov
Keyword(s):  
Experimental Data ◽  
Excited State ◽  
Excited States ◽  
Thermal Emission ◽  
Polarized Light ◽  
Dipole Approximation ◽  
Model Parameters ◽  
Teller Distortion ◽  
Jahn Teller ◽  
Jahn Teller Distortion

AbstractWe have investigated polarization of photoluminescence from the VGaTeAs complexes in n-GaAs induced through resonant excitation by polarized light. Experimental data in temperature range from 77 to 240 K were described by classic one-dipole approximation within the model of the VGaTeAs complex subjected to the Jahn-Teller distortion in the ground and excited states. It is shown that depolarization of photoluminescence at temperatures over ∼ 120 K may be explained by concurrent action of i) thermal emission and back capture of holes bound to the complexes in the excited state and ii) reorientation of complex distortion during a life of this state. The model parameters have been estimated.

scholarly journals Form factors of vector and axial-vector mesons in holographic D4-D8 model

2010 ◽  
Vol 2010 (1) ◽  
Author(s):  
C. A. Ballon Bayona ◽  
Henrique Boschi-Filho ◽  
Nelson R.F. Braga ◽  
Marcus A.C. Torres
Keyword(s):  
Axial Vector ◽  
Form Factors ◽  
Vector Mesons

scholarly journals EXCITED PIONS, ρ- AND ω-MESONS AND THEIR DECAYS IN A CHIRAL SU(2) × SU(2) LAGRANGIAN

1998 ◽  
Vol 13 (32) ◽  
pp. 5443-5457 ◽  
Author(s):  
M. K. VOLKOV ◽  
D. EBERT ◽  
M. NAGY
Keyword(s):  
Experimental Data ◽  
Excited State ◽  
Decay Constant ◽  
Three Dimensional ◽  
Form Factors ◽  
Weak Decay ◽  
Wave Functions ◽  
Spontaneous Breaking ◽  
Gap Equation ◽  
Decay Widths

A chiral SU(2) × SU(2) Lagrangian containing, besides the usual meson fields, their first radial excitations is considered. The Lagrangian is derived by bosonization of the Nambu–Jona-Lasinio (NJL) quark model with separable nonlocal interactions, with form factors corresponding to three-dimensional ground and excited state wave functions. The spontaneous breaking of chiral symmetry is governed by the NJL gap equation. The first radial excitations of the pions, ρ-and ω-mesons are described with the help of two form factors. The weak decay constant Fπ′ is calculated. The values for the decay widths of the processes ρ→2π, π′→ρπ, ρ′→2π, ρ′→ωπ and ω′→ρπ are obtained in agreement with the experimental data.

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