Status of the KLOE-2 experiment at DAΦNE

The KLOE-2 experiment, at the INFN Frascati National Laboratories, represents the continuation of the KLOE experiment. Compared to the previous detector, consisting of a drift chamber and an electromagnetic calorimeter both immersed in a 0.5 T magnetic field, the apparatus has been upgraded with several new detectors; the goal is to study γγ interactions and to improve calorimeter hermeticity and spatial resolution on the vertex position. A single-photon trigger logic was also implemented. The program is to perform high-precision CPT symmetry and quantum coherence tests using neutral kaons, γγ-physics studies and searches of particles of hidden dark-matter sectors, togheter with hadron physics below 1 GeV. KLOE-2 started data taking in November 2014 and is presently collecting data, with the target to collect more than 5 fb−1 integrated luminosity before end of March 201

Low energy kaon-nuclei interaction studies at DAΦNEDA\Phi NE

The aim of the AMADEUS experiment is to investigate the lowenergy antikaon interaction with nucleons and nuclei, exploiting the unique lowmomentum beam of kaons produced by the DAΦNE collider at LNF-INFN, to constrain hadronic nuclear physics models in the strangeness -1 sector. As a first step the data collected in 2004/2005 by the KLOE collaboration, consisting in a complex of K− absorptions in H, 4He, 9Be and 12C, was analyzed, leading to the first invariant mass spectroscopic study with very low momentum (about 100 MeV) in-flight K− captures. A dedicated pure Carbon target was also implemented in the central region of the KLOE detector, providing a high statistic reference sample of pure at-rest K− nuclear interaction. The first measurement of the non-resonant transition amplitude $\left| {{T_{{K^ - }n \to \Lambda {\pi ^ - }}}} \right|$ at $\sqrt s = 33$ MeV below the {\text{\bar KN}} threshold is presented, in relation with the Λ(1405) properties studies

A novel approach to the measurement of the hyperon nucleon/s interaction by AMADEUS

The AMADEUS collaboration is investigating the low-energy antikaon interactions with nucleons and nuclei, taking advantage of the lowmomentum antikaons beam provided by the DAΦNE collider at LNF-INFN. In this work a novel technique is outlined for the measurement of the hyperonnucleon two and three body scattering cross sections. The method consists in producing hyperons by antikaons atomic captures in light nuclear targets, and extrapolating the cross sections from the measurement of the yields of the corresponding elastic final state interactions of the hyperons. The feasibility of this kind of analyses is shown by comparison of calculated Σ0 production in 4He by K− absorption on three nucleons, with a sample of K−12C absorption measured by AMADEUS in collaboration with KLOE. The feasibility of a dedicated high statistics measurement is discussed

First Simultaneous K−^-p →(Σ0/Λ) π0\rightarrow (Σ^0/Λ) \, π^0 Cross Sections Measurements at 98 MeV/c

We report the first simultaneous and independent measurements of the K$^{-}$p $\rightarrow \Sigma^0 \, \pi^{0}$ and K$^{-}$p $\rightarrow \Lambda \, \pi^{0}$ cross sections around 100 MeV/c kaon momentum. The kaon beam delivered by the DA$\Phi$NE collider was exploited to detect K$^-$ absorptions on Hydrogen atoms, populating the gas mixture of the KLOE drift chamber. The precision of the measurements ($\sigma_{K^- p \rightarrow \Sigma^0 \pi^0} = 42.8 \pm 1.5 (stat.) ^{+2.4}_{-2.0}(syst.) \ \mathrm{mb}$ and $\sigma_{K^- p \rightarrow \Lambda \pi^0} = 31.0 \pm 0.5 (stat.) ^{+1.2}_{-1.2}(syst.) \ \mathrm{mb}\,$) is the highest yet obtained in the low kaon momentum regime

Measurement of the Ωc0\Omega_c^0 lifetime at Belle II

We report on a measurement of the $\Omega_c^0$ lifetime using $\Omega_c^0 \to \Omega^-\pi^+$ decays reconstructed in $e^+e^-\to c\bar{c}$ data collected by the Belle II experiment and corresponding to $207~{\rm fb^{-1}}$ of integrated luminosity. The result, $\rm\tau(\Omega_c^0)=243\pm48( stat)\pm11(syst)~fs$, agrees with recent measurements indicating that the $\Omega_c^0$ is not the shortest-lived weakly decaying charmed baryon

Measurement of the Ωc0\Omega_c^0 lifetime at Belle II

We report on a measurement of the $\Omega_c^0$ lifetime using $\Omega_c^0 \to \Omega^-\pi^+$ decays reconstructed in $e^+e^-\to c\bar{c}$ data collected by the Belle II experiment and corresponding to $207~{\rm fb^{-1}}$ of integrated luminosity. The result, $\rm\tau(\Omega_c^0)=243\pm48( stat)\pm11(syst)~fs$, agrees with recent measurements indicating that the $\Omega_c^0$ is not the shortest-lived weakly decaying charmed baryon

Measurement of the Ωc0\Omega_c^0 lifetime at Belle II

We report on a measurement of the $\Omega_c^0$ lifetime using $\Omega_c^0 \to \Omega^-\pi^+$ decays reconstructed in $e^+e^-\to c\bar{c}$ data collected by the Belle II experiment and corresponding to $207~{\rm fb^{-1}}$ of integrated luminosity. The result, $\rm\tau(\Omega_c^0)=243\pm48( stat)\pm11(syst)~fs$, agrees with recent measurements indicating that the $\Omega_c^0$ is not the shortest-lived weakly decaying charmed baryon

Test of light-lepton universality in τ\tau decays with the Belle II experiment

International audienceWe present a measurement of the ratio $R_\mu = \mathcal{B}(\tau^-\to \mu^-\bar\nu_\mu\nu_\tau) / \mathcal{B}(\tau^-\to e^-\bar\nu_e\nu_\tau)$ of branching fractions $\mathcal{B}$ of the $\tau$ lepton decaying to muons or electrons using data collected with the Belle II detector at the SuperKEKB $e^+e^-$ collider. The sample has an integrated luminosity of 362 fb$^{-1}$ at a centre-of-mass energy of 10.58 GeV. Using an optimised event selection, a binned maximum likelihood fit is performed using the momentum spectra of the electron and muon candidates. The result, $R_\mu = 0.9675 \pm 0.0007 \pm 0.0036$, where the first uncertainty is statistical and the second is systematic, is the most precise to date. It provides a stringent test of the light-lepton universality, translating to a ratio of the couplings of the muon and electron to the $W$ boson in $\tau$ decays of $0.9974 \pm 0.0019$, in agreement with the standard model expectation of unity