Related papers: $a_1$ properties in hadronic tau decays
We propose a dispersive representation of the charged pion vector form factor that is consistent with chiral symmetry and fulfills the constraints imposed by analyticity and unitarity. Unknown parameters are fitted to the very precise data…
The most general Lorentz invariant spin-correlation functions for $\tau ^{-}\rightarrow \rho ^{-}\nu ,a_1^{-}\nu ,K^{*-}\nu , \pi ^{-}\nu ,K^{-}\nu $ are expressed in terms of eight semi-leptonic parameters. They are physically defined in…
We show that a single $I=1$ spin-parity $J^{PC}= 1^{++}$ $a_1$ resonance can manifest itself as two separated mass peaks, one decaying into an S-wave $\rho\pi$ system and the second decaying into a P-wave $f_0(980)\pi$ system, with a rapid…
The hypothesis is scrutinized that the weak interaction of hadronic systems at low energies is dominated by the coupling of the pseudoscalar, vector, and axial-vector mesons to the weak gauge bosons. The strength of the weak coupling of the…
The study of the $\tau$-lepton decays into hadrons has contributed to a better understanding of non-perturbative QCD and light-quark meson spectroscopy, as well as to the search of new physics beyond the Standard Model. The two- and…
The most promising source of SUGRA signal at the Tevatron collider is the pair-production of electroweak gauginos, followed by their leptonic decay. In the parameter range corresponding to dominant leptonic decay of these gauginos one or…
We evaluate the $a_1(1260) \to \pi \sigma (f_0(500))$ decay width from the perspective that the $a_1(1260)$ resonance is dynamically generated from the pseudoscalar-vector interaction and the $\sigma$ arises from the…
The consistent matching of short-distance contributions and hadronic matrix elements is crucial for precise predictions of weak processes involving hadrons. In this Letter, we address this point for charged-current processes involving two…
A preliminary measurement of the branching fraction of the tau- -> 3h-2h+nu decay (h= pi, K$) with the BaBar detector is found to be {8.52 +/- 0.09 +/- 0.40} x 10E-4, where the first error is statistical and the second is systematic. The…
A reliable calculation of radiative corrections to $\tau\to\pi\pi\nu_\tau$ decays is an important prerequisite for using hadronic $\tau$ decays for a data-driven evaluation of the hadronic-vacuum-polarization contribution to the anomalous…
The meson spectra provide insight into the particle production mechanism and interaction in the hadronic and quark gluon plasma (QGP) phases. The detailed study of systematics of meson spectra is important also because it acts as ingredient…
Meson-meson amplitudes are important on their own and also play key roles in analyses of heavy-meson and tau decays. In this work we propose a new phenomenological model suited to all $SU(3)$ mesonic two-body final state interactions up to…
The QCD analysis of hadronic tau decays is reviewed and a summary of the present phenomenological status is presented. The following topics are discussed: the determination of alpha_s(m_tau) = 0.338 +- 0.012 from the inclusive tau hadronic…
We discuss strategies to determine hadronic decay couplings from lattice studies. As an application, we explore the decay of a vector meson to two pseudoscalar mesons with $N_f=2$ flavours of sea quark. Although we are working with quark…
We make use of recent accurate results obtained for the pion and kaon vector form factors within a chiral unitary approach in order to calculate the decay widths of the $\tau$ lepton to these mesons and also to evaluate the contribution of…
The decays of light vector mesons into three pseudoscalar mesons are calculated to leading order in the recently proposed counting scheme that is based on the hadrogenesis conjecture. Fully differential as well as integrated decay widths…
Through a specific example of two-body color-favored charm decay, $D_s ^+ \rightarrow \phi \pi^+$, we illustrate how an effective and complex (unitarized) $a_1$, denoted by $a_1^{U,eff}$, may be defined such that it includes nonfactorized,…
We propose to measure the $\tau^-\to K_1^-\nu_\tau \to (K^-\omega) \nu_\tau\to (K^- \pi^+\pi^-\pi^0)\nu_\tau $ decay in order to determine the $K_1$ axial vector mixing angle $\theta_{K_1}$. We derive, for the first time, the differential…
Semileptonic exclusive tau decays in the Standard Model are reviewed. As it is well-known, they are a privileged arena to learn about low-energy hadronization. They also allow for a number of clean new physics tests, which have attracted…
In the two body hadronic tau decays, such as tau->to K pi (eta)nu, vector mesons play important role. Belle and Babar measured hadronic invariant mass spectrum of tau -> K pi nu decay. To compare the spectrum with theoretical prediction, we…