One-meson radiative tau decays

Abstract

We have studied the one-meson radiative tau decays À ! À ðK À Þ, computing the structuredependent contributions within a Lagrangian approach based on the large-N C limit of QCD that ensures the proper low-energy limit dictated by chiral symmetry. Upon imposing the short-distance QCD constraints to the form factors, we are able to predict the structure-dependent radiation without any free parameter and, therefore, the relevant observables for the decay À ! À : the photon energy spectrum, the invariant mass spectrum of the meson-photon system, and the integrated decay rate. We also discuss the remaining uncertainties in these observables for the À ! K À decay. According to our results, the present facilities could detect these rare decays for the first time in the near future, allowing for a stringent test of our predictions.

Theoretical inputs and errors in the new hadronic currents in TAUOLA

“…Some of the abundant new couplings can be related upon imposing that the imaginary part of the VV and AA correlators go to zero asymptotically in the large-N C limit [24]. It is noteworthy that the relations found are in agreement for all three cases, and with those obtained in the one-meson radiative tau decays [25].…”

Unified study ofJ/ψ→PV,Pγ(*)Chen1, Guo2, Zou3 2015Phys. Rev. DSelf Cite281240View full textAdd to dashboardCite

“…To impose the high energy constraints to the couplings can greatly reduce the number of free parameters in RχT [26,29,48]. This procedure also renders the amplitudes calculated in RχT consistent with the behavior dictated by QCD.…”

“…Guided by chiral symmetry and large N C expansion, resonance chiral theory (RχT) [23] provides us a reliable theoretical framework to study the interaction between the light flavor resonances and pNGBs in the intermediate energy region and it has been successfully applied in many phenomenological processes [24][25][26][27][28][29][30][31][32]. The building blocks involving resonance states from RχT [23] will be also employed in our present work to construct the relevant effective Lagrangian describing the interactions between light hadrons and the J/ψ.…”

The vector form factor at the next-to-leading order in 1/N C : chiral couplings L9(μ) and C88(μ) − C90(μ)

“…[27] from the LO ππ scattering amplitude. It is interesting to remark that the c d = 0 limit of this second relation, G V = F/ √ 3, has been obtained recently from a study of τ − → P − γ ν τ decays (P = π, K) [28]. We have used these constraints to fix F V and c 2 d .…”