Related papers: The $\pi^+$--emission puzzle in $^4_\Lambda$He dec…
The problem of $\rho$- and $\omega$- mesons contributions to the background for $\eta \to \pi^0 e^+e^-$ decay and to the asymmetries in the decays $\eta \to \pi^+\pi^-\pi^0$ and $\eta \to \pi^+\pi^-\gamma$ is considered.
At the Mainz Microtron MAMI, the first high-resolution pion spectroscopy from decays of strange systems was performed by electron scattering off a Be-9 target in order to study the ground-state masses of Lambda-hypernuclei. Positively…
The two-body scattering length a for 4He atoms is much larger than their effective range r_s. As a consequence, low-energy few-body observables have universal characteristics that are independent of the interaction potential. Universality…
We report on results of an experimental search for the K_L -> pi^+ pi^- e^+ e^- decay mode. We found 13.5 +- 4.0 events and determined its branching ratio to be (4.4 +- 1.3(stat) +- 0.5(syst))*10^{-7}. The result agrees well with the…
We measured the lifetime and the mesonic and non-mesonic decay rates of the 4He-Lambda hypernucleus. The hypernuclei were created using a 750 MeV/c momentum K- beam on a liquid 4He target by the reaction 4He(K-,pi-)4He-Lambda. The…
We address the $\Lambda$-hypernuclear `overbinding problem' in light hypernuclei which stands for a 1--3 MeV excessive $\Lambda$ separation energy calculated in $_{\Lambda}^5$He. This problem arises in most few-body calculations that…
Inspired by the newly observed $\Lambda_b(6072)$ structure, we investigate its strong decay behaviors under various assignments within the $^3P_0$ model. Compared with the mass and total decay width, our results suggest that the…
The four-body decays $D^+ \to K^-\pi^+e^+\nu_e$ ($D_{e4}^+$) and $D^0\to \overline{K^0}\pi^-e^+\nu_e$ ($D^0_{e4}$) are studied in a model where the momentum-dependence of the hadronic matrix elements are described in terms of $K^*(892)$ and…
This work is dedicated to the search for a $\pi\Lambda N\!-\!\pi\Sigma N$ resonance $\mathcal{Y}$ with the quantum numbers ($Y,I,J^P$) = (1,3/2,$2^+$). The double charged $\Sigma(1385)N\!-\!\Delta(1232)Y$ quasibound state was looked for in…
Motivated by the LHCb measurement of the hyperon decay mode $\Sigma^+\to p\mu^+\mu^-$ and prospects for improvement, we revisit the estimates for the rate and muon forward-backward asymmetry within the standard model and beyond. The…
Based on a sample of $(2712.4\pm14.3)\times10^6\;\psi(3686)$ events collected with the BESIII detector, a partial wave analysis of the decay $\psi(3686)\to\Lambda\bar\Sigma^0\pi^0+c.c.$ is performed to investigate $\Lambda^*$ and $\Sigma^*$…
Recent experimental results for the reaction \gamma + p \to K^+ + \Sigma + \pi\ from CLAS at Jefferson Lab are discussed. It was found that the mass distributions or "line shapes" of the three charge combinations \Sigma^+ \pi^-, \Sigma^0…
The HyperCP collaboration observed three events for the decay Sigma to p mu+ mu-. They suggested that new physics may be required to understand the implied decay rate and the observed dimuon invariant mass distribution. Motivated by this…
We have studied the three-particle decay of 12C, 9Be and 6Be resonances. These nuclei have been described as three-body systems by means of the complex scaled hyperspherical adiabatic expansion method. The short-distance part of the…
The focus of these Lectures is on the weak decay modes of hypernuclei, with special attention to Lambda-hypernuclei. The subject involves many fields of modern theoretical and experimental physics, from nuclear structure to the fundamental…
We report on a comparison of two possible $\Lambda_c^+$ spin hypotheses, $J=\frac{1}{2}$ and $\frac{3}{2}$, via the process $e^+e^-\to\Lambda_c^+\bar\Lambda_c^-$, using the angular distributions of $\Lambda_c^+$ decays into $pK_S^0$,…
We investigate the decay of $a^+_1(1260) \to \pi^+ \pi^+ \pi^-$ with the assumption that the $a_1(1260)$ is dynamically generated from the coupled channel $\rho \pi$ and $\bar{K}K^*$ interactions. In addition to the tree level diagrams that…
Using q-theory, we show that the electroweak crossover can generate a remnant vacuum energy density \Lambda \sim E_{ew}^8 / E_{planck}^4, with effective electroweak energy scale E_{ew} \sim 10^{3} GeV and reduced Planck-energy scale…
We extend the application of lattice QCD to the two-photon-mediated, order $\alpha^2$ rare decay $\pi^0\rightarrow e^+ e^-$. By combining Minkowski- and Euclidean-space methods we are able to calculate the complex amplitude describing this…
We present measurements of the Cabibbo-suppressed decays $\Lambda_c^+ \to \Lambda^0 K^+$ and $\Lambda_c^+ \to \Sigma^0 K^+$ (both first observations), $\Lambda_c^+ \to \Sigma^+ K^+\pi^-$ (seen with large statistics for the first time),…