Search results for "Direct observations"
showing 2 items of 2 documents
Improved limit on the directly measured antiproton lifetime
2017
Continuous monitoring of a cloud of antiprotons stored in a Penning trap for 405 days enables us to set an improved limit on the directly measured antiproton lifetime. From our measurements we extract a storage time of $3.15\times {10}^{8}$ equivalent antiproton-seconds, resulting in a lower lifetime limit of ${\tau }_{\bar{{\rm{p}}}}\gt 10.2\,{\rm{a}}$ with a confidence level of $68 \% $. This result improves the limit on charge-parity-time violation in antiproton decays based on direct observation by a factor of 7.
Observation of Photon Polarization in theb→sγTransition
2014
This Letter presents a study of the flavor-changing neutral current radiative $B^{\pm} \to K^{\pm}\pi^{\mp}\pi^{\pm}\gamma$ decays performed using data collected in proton-proton collisions with the LHCb detector at $7$ and $8\,$TeV center-of-mass energies. In this sample, corresponding to an integrated luminosity of $3\,\text{fb}^{-1}$, nearly $14\,000$ signal events are reconstructed and selected, containing all possible intermediate resonances with a $K^{\pm}\pi^{\mp}\pi^{\pm}$ final state in the $[1.1, 1.9]\,$GeV/$c^{2}$ mass range. The distribution of the angle of the photon direction with respect to the plane defined by the final-state hadrons in their rest frame is studied in interva…