Measurement of the growth rate with type Ia supernovae

• Bastien Carreres (CPPM)

Type Ia supernovae are known to be standard candles, that means that we can infer their distance from their flux measurement and build their Hubble Diagram. Peculiar velocities can be retrieved from the HD residuals, but until now the statistic of SN Ia was too low to use these velocities as cosmological probes. With the next generation of surveys (LSST, ZTF) the statistics of supernovae will grow in an unprecedented way, making the use of SN Ia peculiar velocities useful to measure the growth rate and to complement current measurements using galaxy surveys. In this talk, we propose to present our current work on the analysis to measure the growth rate using SN Ia, with the methodology and the study of bias estimation and mitigation.

Neutrino Tagging feasibility study with NA62 data

• Bianca DE MARTINO ({CNRS}UMR7346)

The neutrino tagging technique is a new experimental method for accelerator based neutrino experiments. This technique consists in instrumenting a beam line with silicon trackers. Using these trackers, each neutrino originating from a $\pi^\pm \to \mu^\pm \nu$ decay can be reconstructed based on simple kinematic relations, allowing to precisely determine the main properties of each beam neutrino. The feasibility of this technique can be studied using the data collected by the NA62 experiment with a dedicated trigger line. The NA62 experiment is a fixed target particle physics experiment in the North Area of the SPS accelerator at CERN, whose purpose is to measure the branching ratio of the rare $K^+\rightarrow\pi\nu\nu$ decay thanks to a very intense K+ beam. The beam spectrometer and the straw tube spectrometer of the NA62 experiment can be exploited to reconstruct the charged particles of main decay mode of the K+, $K^+ \rightarrow \mu^+ \nu$. The activity associated to the $\nu$ interaction in the calorimeters of the NA62 experiment can be matched to the reconstructed charged particles. This contribution describes the dedicated trigger line and the signal selection, and presents the status of the analysis.

Measurement of $CP$-violating observables in $B^0 \to D^* \mu \nu$ decays at the LHCb experiment

• Vlad Dedu (Aix-Marseille-University, CNRS/IN2P3, CPPM, Marseille, France)

Intriguing hints on possible deviations from the predictions of the Standard Model (SM) are reported in the studies of $b\to c\ell \nu$ transitions. At present, the discrepancies are present in the measurements of the ratios of branching fractions of the B mesons into the final states involving tau-lepton and muon, such as $R_{D^*} = \mathcal{B}(B^0 \to D^* \tau \nu)/\mathcal{B}(B^0 \to \mu \nu)$. To confirm or disprove these deviations, as well as to distinguish between various New Physics (NP) models that could explain these anomalies, one has to study other experimental observables. $CP$-violating observables in the semileptonic decays were suggested as promising means to differentiate various NP scenarios. In this analysis, we aim to perform the first study of $CP$-violating observables in the $b\to c\ell \nu$ transitions, namely in the decay $B^0 \to D^* \mu \nu$ using data collected by the LHCb detector at CERN.