The ${\ensuremath{\eta}}^{\ensuremath{'}}$ transition form factor is reanalyzed in view of the recent first observation by BESIII Dalitz decay ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\gamma}{e}^{+}{e}^{\ensuremath{-}}$ both space- and timelike regions at low intermediate energies using Pad\'e approximants method. present analysis provides a suitable parametrization for reproducing measured whole energy region allows one to extract corresponding low-energy...

We analyze the second-class current decays ${\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\eta}}^{(\ensuremath{'})}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ in framework of chiral perturbation theory with resonances. Taking into account ${\ensuremath{\pi}}^{0}\text{\ensuremath{-}}\ensuremath{\eta}\text{\ensuremath{-}}{\ensuremath{\eta}}^{\ensuremath{'}}$ mixing,...

A bstract It has been long-understood that final state rescattering effects provide $$ \mathcal{O} <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> </mml:math> (1) corrections to hadronic meson decays rates, such as η → πππ and ′ ηππ . Hence, one would expect be just important in axio-hadronic decays, ( ) ππa , where a is an axion or axion-like particle (ALP). And indeed they are, we show this paper by using the treatment of dispersion relations include strong...

The possibility for the existence of a leptophobic $U(1)$ gauge boson associated to baryon symmetry is scrutinized in MeV-GeV mass range by means an exhaustive analysis corresponding golden channels $\eta\to\pi^0\gamma\gamma$ and $\phi\to\pi^0\eta\gamma$. Using latest experimental data on these two processes taken also into account Standard Model contributions from scalar vector meson exchanges, we are able obtain best 95\% exclusion limits up-to-date $m_B$ coupling $\alpha_B$ known...

We perform a global analysis of exclusive hadronic tau decays into one and two mesons using the low-energy limit Standard Model Effective Field Theory up to dimension six, assuming left-handed neutrinos. A controlled theoretical input on form factors, based chiral symmetry, dispersion relations, data asymptotic QCD properties, has allowed us set bounds New Physics effective couplings present experimental data. Our results highlight importance semileptonic $τ$ in complementing traditional...

A bstract Working with Resonance Chiral Theory, within the two resonance multiplets saturation scheme, we satisfy leading (and some subleading) chiral and asymptotic QCD constraints accurately fit simultaneously π 0 , η, η ′ transition form factors, for single double virtuality. In latter case, supplement few available measurements lattice data to ensure a faithful description. Mainly due new results doubly virtual improve over existing descriptions ′. Our evaluation of corresponding pole...

The dilepton invariant mass spectra and integrated branching ratios of the single double Dalitz decays $\mathcal{P}\to\ell^{+}\ell^{-}\gamma$ $\mathcal{P}\to\ell^{+}\ell^{-}\ell^{+}\ell^{-}$ ($\mathcal{P}=\pi^{0}, \eta, \eta^{\prime}$; $\ell=e$ or $\mu$) are predicted by means a data-driven approach based on use rational approximants applied to $\pi^{0}, \eta$ $\eta^{\prime}$ transition form factor experimental data in space-like region.

The discovery of ${\mathrm{\ensuremath{\Xi}}}_{cc}^{++}$ by the LHCb Collaboration triggers predictions more doubly charmed baryons. By taking into account both $P$-wave excitations between two charm quarks and scattering light pseudoscalar mesons off ground state baryons, a set negative-parity spin-$1/2$ baryons are predicted already from unitarized version leading order chiral perturbation theory. Moreover, employing heavy antiquark-diquark symmetry, relevant low-energy constants in...

In a combined study of the decay spectra τ − K S π ν and ην decays within dispersive representation required form factors, we illustrate how *(1410) resonance parameters, defined through pole position in complex plane, can be extracted with improved precision as compared to previous studies. While obtain substantial improvement mass, uncertainty width is only slightly reduced, findings M K*′ = 1304 ± 17 MeV Γ 171 62 MeV. Further constraints on could result from updated analyses Kπ and/or Kη...

The scalar and vector meson exchange contributions to the doubly radiative decays ${\ensuremath{\eta}}^{(\ensuremath{'})}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}\ensuremath{\gamma}\ensuremath{\gamma}$ ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\eta}\ensuremath{\gamma}\ensuremath{\gamma}$ are analyzed within linear sigma model dominance frameworks, respectively. Predictions for diphoton invariant mass spectra associated integrated branching ratios given...

In light of the first observation semileptonic decay $B^{0}_{s}\to K^{-}\mu^{+}\nu_{\mu}$ by LHCb collaboration, we revisit determination CKM parameter $|V_{ub}|$ from exclusive $B$-meson decays. A controlled theoretical input on Standard Model $B\to\pi$ and $B_{s}\to K$ vector scalar form factors Lattice QCD in large $q^{2}$ region, combination with experimental measurements differential $B\to\pi\ell\nu_{\ell}$ branching ratio distributions, has allowed us determine...

We study the hadronic $$\eta ^{\prime }\rightarrow \eta \pi $$ decays within framework of $$U(3)_{L}\otimes U(3)_{R}$$ Chiral Perturbation Theory including resonance states and complete one-loop corrections. The amplitude is projected in partial waves unitarized by means N / D method resumming both important S- D-wave $$\pi subleading S-wave final-state interactions. participating scalar multiplet mass coupling strengths are determined from fits to Dalitz plot experimental data recently...

We explore the potential of a combined analysis decays $$\tau ^{-}\rightarrow \pi ^{-}\pi ^{0}\nu _{\tau }$$ and K^{-}K_{S}\nu in determination $$\rho (1450)$$ (1700)$$ resonance properties frame Chiral Theory supplemented by dispersion relations. On one hand, we take advantage very precise data on modulus squared pion vector form factor $$|F_{V}^{\pi }|^{2}$$ obtained Belle to carry out dedicated region where these resonances come up into play. Our study provides an improved treatment...

Abstract In light of recent experimental results, we revisit the dispersive analysis $$\omega \rightarrow 3\pi $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>ω</mml:mi> <mml:mo>→</mml:mo> <mml:mn>3</mml:mn> <mml:mi>π</mml:mi> </mml:mrow> </mml:math> decay amplitude and \pi ^0$$ <mml:msup> <mml:mn>0</mml:mn> </mml:msup> transition form factor. Within framework Khuri–Treiman equations, show that Dalitz-plot parameters obtained with a once-subtracted are in...

We analyze the decays ${\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}({\ensuremath{\eta}}^{(\ensuremath{'})},{K}^{0}){\ensuremath{\nu}}_{\ensuremath{\tau}}$ within an effective-field theory that includes most general interactions between Standard Model fields up to dimension six, assuming left-handed neutrinos. In particular, we examine different interesting phenomenological observables, i.e., decay spectra and branching ratio, Dalitz plot distributions,...

We reassess the $B\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\ell}{\ensuremath{\nu}}_{\ensuremath{\ell}}$ differential branching ratio distribution experimental data released by BABAR and Belle Collaborations supplemented with all lattice calculations of $B\ensuremath{\rightarrow}\ensuremath{\pi}$ form factor shape available to date obtained HPQCD, FNAL/MILC, RBC/UKQCD Collaborations. Our study is based on method Pad\'e approximants includes a detailed scrutiny each individual set...

We study the evolution of plasma instabilities induced by two jets particles propagating in opposite directions and crossing a thermally equilibrated non-Abelian plasma. In order to simplify analysis we assume that partons can be described with uniform distribution functions coordinate space Gaussian momentum space. find while quark-gluon plasma, excite unstable chromomagnetic chromoelectric modes. These fields interact (or hard modes) inducing production currents; thus, energy lost is...

We study the doubly radiative decays $\eta^{(\prime)}\to\pi^0\gamma\gamma$ and $\eta^\prime\to\eta\gamma\gamma$ in terms of vector scalar meson exchange contributions using, respectively, frameworks Vector Meson Dominance Linear Sigma model. Predictions for $m_{\gamma\gamma}^{2}$ invariant mass distribution branching ratios are given, a discussion how they compare to experimental data is carried out.

It has been long-understood that final state rescattering effects provide $\mathcal{O}(1)$ corrections to hadronic meson decays rates, such as $\eta\to\pi\pi\pi$ and $\eta^{\prime}\to\eta\pi\pi$. Hence, one would expect be just important in axio-hadronic $\eta$ $\eta^{\prime}$ decays, $\eta^{(\prime)}\to\pi\pi a$, where $a$ is an axion or axion-like particle (ALP). And indeed they are, we show this paper by using the treatment of dispersion relations include strong interactions several...

Working with Resonance Chiral Theory, within the two resonance multiplets saturation scheme, we satisfy leading (and some subleading) chiral and asymptotic QCD constraints accurately fit simultaneously $\pi^{0},\eta,\eta^{\prime}$ transition form factors, for single double virtuality. In latter case, supplement few available measurements lattice data to ensure a faithful description. Mainly due new results doubly virtual improve over existing descriptions $\eta$ $\eta^\prime$. Our evaluation...

In light of recent experimental results, we revisit the dispersive analysis $\omega \to 3\pi$ decay amplitude and $\omega\pi^0$ transition form factor. Within framework Khuri-Treiman equations, show that Dalitz-plot parameters obtained with a once-subtracted are in agreement latest determination by BESIII. Furthermore, at low energies factor from our is consistent data MAMI NA60 experiments.

The potential of performing a combined analysis the strangeness-changing decays $\tau^{-}\to K_{S}\pi^{-}\nu_{\tau}$ and K^{-}\eta\nu_{\tau}$ for unveiling $K^{*}(1410)$ resonance pole parameters is illustrated. Our study carried out within framework Chiral Perturbation Theory, including resonances as explicit degrees freedom. Resummation final state interactions are considered through dispersive parameterization required form factors. A considerable improvement in determination position...

We illustrate the powerfulness of Padé approximants (PAs) as a summation method and explore one their extensions, so-called quadratic approximant (QAs), to access both space- (low-energy) time-like (TL) regions. As an introductory pedagogical exercise, function [Formula: see text] is approximated by kind approximants. Then, PAs are applied predict pseudoscalar meson Dalitz decays extract from semileptonic decays. Finally, vector form factor in TL region explored using QAs.