Related papers: Predictions for the cusp in eta->3pi0 decay
We obtain explicit expressions for the \eta and \eta' masses and decay constants using U_L(3) x U_R(3) chiral perturbation theory at next-to-leading order in a combined expansion in p^2 and 1/Nc. A numerical fit of the parameters appearing…
Consistency constraints for low-energy theories, especially those lacking Lorentz invariance, have recently garnered attention. Building on results from black hole thermodynamics, we investigate the conjecture that leading irrelevant…
We show the discrepancy between the isospin-rotated $e^+e^-\to\eta\pi^-\pi^+$ cross-section -- measured by various collaborations -- and the Belle $\tau^-\to\eta\pi^-\pi^0\nu_\tau$ spectrum, which cannot be explained by heavy new physics…
The top quark is expected to be a probe to new physics beyond the standard model. Thanks to the large number of top quarks produced at the Tevatron and the LHC, various properties of the top quark can now be measured accurately. An…
Taking into account mixings among neutrino states, the end of the energy spectrum of the electron in the tritium beta decay is investigated. It is shown that for real energy resolutions of a spectrometer, $ \Delta E > 0.08$ eV, the…
This is the first in a series of papers, in which we compute the third-order QCD corrections to top-antitop production near threshold in e+ e- collisions. The present paper provides a detailed outline of the strategy of computation in the…
We note that the fine structure at the endpoint region of the beta decay spectrum is now essentially known using neutrino oscillation data, if the mass of one neutrino is specified. This may help to identify the effects of nonzero neutrino…
We have observed new channels for $\tau$ decays with an $\eta$ in the final state. We study 3-prong tau decays, using the $\eta\to\gamma\gamma$ and $\eta\to 3\piz$ decay modes and 1-prong decays with two $\piz$'s using the…
\pi and \eta decay modes of light baryon resonances are investigated within a chiral quark model whose hyperfine interaction is based on Goldstone-boson exchange. For the decay mechanism a modified version of the 3P0 model is employed. Our…
Axions can be described by a relativistic field theory with a real scalar field $\phi$ whose self-interaction potential is a periodic function of $\phi$. Low-energy axions, such as those produced in the early universe by the vacuum…
We investigate the decays of pi^0, eta and eta-prime into two photons in an effective U(3) chiral Lagrangian approach without employing large N_c arguments. Tree level and one-loop contributions from the anomalous Wess-Zumino-Witten…
We consider a particle coupled to a dissipative environment and derive a perturbative formula for the dephasing rate based on the purity of the reduced probability matrix. We apply this formula to the problem of a particle on a ring, that…
In this work we studied $\beta$-decay properties for deformed neutron-rich nuclei in the region Z=36-43. We use the deformed pn-QRPA methods with the realistic CD-Bonn forces, and include both the Gamow-Teller and first-forbidden types of…
In this talk I give a short introduction to hard pion Chiral Perturbation Theory and an overview of the available applications $K\to\pi\pi$, $B,D\to D,\pi,K,\eta$ semileptonic decays and $\chi_{c0,2}\to\pi\pi,KK$. It is pointed out that the…
I give a brief outline of the theoretical framework for the modern treatment of the strong interaction effects in heavy quark decays, based on first principles of QCD. This model-independent approach is required to meet the precision of…
We analyze the clean cusp, seen in the $\eta \pi$ mass distribution with high precision of the $\chi_{c1} \to \eta \pi^+ \pi^-$ reaction in the BESIII experiment, with the aim of making a precise determination of the scattering length $a$…
The effective field theory with contact interactions alone is a powerful tool to compute low-energy observables for three-body systems with large scattering length. Recent calculations including effective range corrections are discussed and…
Relativistic effects in a three-body calculation of the $np\to\eta d$ process are considered. Relativistic effects on the range and strength of the pion exchange contribution to the reaction mechanism may be large, but boost effects of the…
Effective chiral theory of mesons is applied to study the four decay modes of $\tau\to\rho\pi\pi\nu$. Theoretical values of the branching ratios are in agreement with the data. The theory predicts that the $a_{1}$ resonance plays a dominant…
Decays of both $\eta$ and $\eta^\prime$ provide very useful information in our understanding of low-energy QCD, and experimental signatures for these decays would be extremely helpful at BES-III. The rare decays of the $\eta$ and…