[en] We present a measurement of the time-dependent CP asymmetry in the radiative-penguin decay B⁰ → K⁰_Sπ⁺π^-γ, using a sample of 470.9 million Υ(4S) → BB-bar events recorded with the BABAR detector at the PEP-II e⁺e^- storage ring at SLAC. Using events with m_Kππ < 1.8 GeV/c², 0.6 < m_ππ < 0.9 GeV/c² and with m_Kπ < 0.845 GeV/c² and m_Kπ > 0.945 GeV/c², we obtain the CP-violating parameters S(K⁰_Sπ⁺π^-γ) = 0.137±0.249^+0.042_-0.033 and C(K⁰_Sπ⁺π^-γ) = -0.390±0.204^+0.045_-0.050, where the first quoted errors are statistical and the second are systematic. We extract from this measurement the time-dependent CP asymmetry related to the hadronic CP eigenstate ρ⁰K⁰_S and obtain S(K⁰_Sργ) = 0.249±0.455^+0.076_-0.060. This observable provides information on the photon polarization in the underlying b → sγ transition. To extract S(K⁰_S ργ) from S(K⁰_S π⁺π^γ), assuming isospin symmetry, we study B⁺ → K⁺π⁺π^-γ decays and measure intermediate resonant amplitudes of different resonances decaying to Kππ through the intermediate states ρ⁰K⁺, K*⁰π⁺ and (Kπ)_S-waveπ⁺. In addition to the need of this information for the extraction of S(K⁰_S ργ), it provides input on the B → Kππ system, which is useful for other studies of the photon polarization. The fractions of the different K_res → Kππ states as well as the overall fractions of the ρ⁰K⁺, K*⁰π⁺ and (Kπ)_S-waveπ⁺ components are also measured. (author)

[en] The locations of proton-proton collision points in LHC experiments are called primary vertices (PVs). Preliminary results of a hybrid deep learning algorithm for identifying and locating these, targeting the Run 3 incarnation of LHCb, have been described at conferences in 2019 and 2020. In the past year we have made significant progress in a variety of related areas. Using two newer Kernel Density Estimators (KDEs) as input feature sets improves the fidelity of the models, as does using full LHCb simulation rather than the “toy Monte Carlo” originally (and still) used to develop models. We have also built a deep learning model to calculate the KDEs from track information. Connecting a tracks-to-KDE model to a KDE-to-hists model used to find PVs provides a proof-of-concept that a single deep learning model can use track information to find PVs with high efficiency and high fidelity. We have studied a variety of models systematically to understand how variations in their architectures affect performance. While the studies reported here are specific to the LHCb geometry and operating conditions, the results suggest that the same approach could be used by the ATLAS and CMS experiments.

[en] We present recent results from the BABAR Collaboration on radiative decays. These include searches for new physics via measurements of several observables such as the time- dependent CP asymmetry in B"0 → K"0_Sπ"−π"+γ exclusive decays, as well as direct CP asymmetries and branching fractions in B → X_sγ and B → X_sℓ"+ℓ"− inclusive decays

[en] This publication gathers 51 contributions made by PhD students and session coordinators on traditional topics (astro-particles, cosmology, standard model) and on instrumentation, neutrinos, nuclear physics and hadronics. As far as astro-particles are concerned, the subjects were: Life and work of astro-particles; Alpha Magnetic Spectrometer 02, a particle sensor on the International Space Station; Anisotropy of cosmic radiation between 10 GeV and 100 TeV; H.E.S.S. and the cosmic accelerators called blazars; Ultra-high energy neutrinos at the Pierre Auger Laboratory; Autonomous radio-detection of high-energy cosmic rays with Codalema. The second theme was 'Beyond the standard model': Physics beyond the standard model; Probing the photon helicity: from BABAR to LHCb; The search for a new physics in the t t invariant mass spectrum with the CMS experiment; To connect supersymmetry and dark matter; Fine tuning in the NMSSM according to the results at 1fb"-"1 of the LHC; Search for new physics in events with 4 top quarks in the ATLAS experiment. For cosmology: Cosmological context; Physical properties of type Ia supernovae, the contribution of SNLS and SNFactory experiments; Reconstruction and analysis of the Sungaev-Zel'dovich effect with Planck; Local host galaxy properties of type Ia supernovae from the Nearby SuperNovae Factory; Observational cosmology with the Planck satellite: the re-ionization. For instrumentation: Introduction to instrumentation; ALFA, Absolute Luminosity For Atlas; Development of the mirrors for the second generation gravitational waves detector Advanced Virgo; EASIER, a radio detector at the Pierre Auger Laboratory; Spectral analysis algorithms in on-board gamma spectrometry; For the Standard Model: Introduction to the session; Triggering optimisation on electrons in CMS; The search for the Higgs boson in the process of vector boson fusion production and study of photon trigger with ATLAS at the LHC; Analysis of the Charmless decay B"0 → ρπ in the LHCb experiment; Correction of radiations in the final state in H → ZZ"* → 4I; Towards a measurement of the γ angle of the CKM theory via the B"0 → D"0K"+"0 disintegration with the LHCb detector; Measurement of the photon pair production cross section in the LHC with the ATLAS detector; The search for the Higgs in the 4-electron channel in ATLAS; Search for the Higgs boson in the H → γγ decay channel with the ATLAS detector. For neutrinos: Neutrino physics; The search for the double β disintegration without neutrino emission in the NEMO experiments; Coincident searches between gravitational waves and high-energy neutrinos with the ANTARES and LIGO/Virgo detectors; Use of the NA61-SHINE data to improve the prediction of the neutrino beam at T2K. For hadronic physics: A phenomenological study of helicity amplitudes of high energy exclusive lepto-production of the ρ-meson; Proton antiproton annihilation into heavy leptons at PANDA experiment; Study of the density of particles charged in collisions of heavy ions in the ALICE experiment at the LHC; Photon + heavy-flavor jet production at Tevatron and LHC; Quarkonium production in ultra-relativistic heavy-ion collisions with the ALICE experiment at the LHC; Loop calculations in gage theories. The last theme was nuclear physics and applications: Introduction to the session; Measurement of mass yields of the reaction "2"4"1Am(2n,f) at the Lohengrin spectrometer; Xenon mobility in uranium dioxide; Ga-Ni coating obtained by electrodeposition in chloride environment