Related papers: Hyperon weak radiative decays in chiral perturbati…
It is shown that an alternative form of the parity-nonconserving (PNC) transition electromagnetic current resolves partly a puzzle with the Hara theorem. New formulation of it has allowed PNC weak radiative hyperon transitions of the…
In this paper, we study the low energy kaon-hyperon interaction considering effective chiral Lagrangians that include kaons, $\sigma$ mesons, hyperons and the corresponding resonances. The scattering amplitudes are calculated and then we…
These lectures are an introduction to the subject of chiral effective Lagrangians of the Standard Model and their applications, mostly in the sector of non--leptonic kaon decays, with special emphasis on CP--violation. The first lecture…
The strangeness-changing ($\Delta S = 1$) weak baryon-baryon interaction is studied through the nonmesonic weak decay of double-$\Lambda$ hypernuclei. Besides the usual nucleon-induced decay $\Lambda N \to N N$ we discuss novel…
Heavy baryon chiral perturbation theory including spin 3/2 delta resonances as effective degrees of freedom is reviewed. The theory admits a systematic expansion in the small scale $\epsilon$, where $\epsilon$ collectively denotes soft…
In this Letter, a systematic study of the weak radiative hyperon decay $\Xi^{0}\to\Lambda\gamma$ at an electron-positron collider using entangled $\Xi^{0}\bar{\Xi}^{0}$ pair events is presented. The absolute branching fraction for this…
Chiral symmetry serves as a guiding principle in low-energy hadron dynamics. An effective lagrangian, which explicitly breaks chiral symmetry via a small mass term, allows for a systematic method of calculating higher order corrections to…
Weak radiative hyperon decays represent a rich interplay between weak interactions and the internal structure of baryons, offering profound insights into Quantum Chromodynamics and weak interactions. Recent experimental observations,…
In this work we study the low energy kaon-hyperon interaction considering effective chiral Lagrangians that include kaons, $\sigma$ mesons, hyperons and the corresponding resonances. We calculate the scattering amplitudes, and then the…
The weak decays $K^\pm\to\pi^\pm a$ offer a powerful probe of axion-like particles (ALPs). In this work, we provide a comprehensive analysis of these processes within chiral perturbation theory, extending existing calculations by including…
The processes involving low energy $\bar{K}N$ and $Y\pi$ interactions (where $Y= \Sigma$ or $\Lambda$) are studied in the framework of heavy baryon chiral perturbation theory with the $\Lambda$(1405) resonance appearing as an independent…
We report on the recently proposed joint resolution of two long-standing puzzles in weak radiative (WR) and nonleptonic (NL) hyperon decays (HD). First, a good VMD-based description of WRHD is presented. In particular, the large negative…
We re-investigate the radiative charged kaon decay K+- --> pi0 e+- nu_e gamma in chiral perturbation theory, merging the chiral expansion with Low's theorem. We thoroughly analyze the precision of the predicted branching ratio relative to…
We evaluate the amplitude for $\gamma \gamma \rightarrow \pi^0 \pi^0$ to two loops in chiral perturbation theory. The three new counterterms which enter at this order in the low-energy expansion are estimated with resonance saturation. We…
The ten nonleptonic weak decays $K \to 2\pi$, $K \to 3\pi$, $K_L \to 2\gamma$, $K_S \to 2\gamma$, $K_L \to \pi^\circ 2\gamma$, are predicted for a chiral pole model based on the linear sigma model theory which automatically satisfies the…
Using non relativistic effective Lagrangian techniques, we analyze the hadronic decay of the pi+pi- atom and the strong energy-level shift of pionic hydrogen in the ground state. We derive general formulae for the width and level shift,…
The interplay between the chiral anomaly and the non-leptonic weak Hamiltonian is studied. The structure of the corresponding effective Lagrangian of odd intrinsic parity is established. It is shown that the factorizable contributions…
We report on the result of some investigations concerning the radiative decays of decuplet baryons and the non-leptonic weak decays of the octet baryons in the context of topological chiral soliton models. Our results are compared with…
This talk concerns some theoretical patterns of the helicity amplitudes for t --> W b decay. The patterns involve both the standard model's four decay helicity amplitudes, A_{SM}, and also the amplitudes A_{+} in the case of an additional…
The masses and decays of the scalar D_{s0}^*(2317) and axial-vector D_{s1}^*(2460) charmed strange mesons are calculated consistently in the hadrogenesis conjecture. These mesons decay either strongly into the isospin-violating pi^0 D_s and…