Bruno Angelucci

CAEN S.p.A. | CAEN · R&D

A search for the K+→μ−νe+e+ decay, forbidden within the Standard Model by either lepton number or lepton flavour conservation depending on the flavour of the emitted neutrino, has been performed using the dataset collected by the NA62 experiment at CERN in 2016–2018. An upper limit of 8.1×10−11 is obtained for the decay branching fraction at 90% CL...

A bstract A sample of 2 . 8 × 10 ⁴ K ⁺ → π ⁺ μ ⁺ μ − candidates with negligible background was collected by the NA62 experiment at the CERN SPS in 2017–2018. The model-independent branching fraction is measured to be (9 . 15 ± 0 . 08) × 10 − 8 , a factor three more precise than previous measurements. The decay form factor is presented as a function...

Searches for lepton number violating K+→π−e+e+ and K+→π−π0e+e+ decays have been performed using the complete dataset collected by the NA62 experiment at CERN in 2016–2018. Upper limits of 5.3×10−11 and 8.5×10−10 are obtained on the decay branching fractions at 90% confidence level. The former result improves by a factor of four over the previous be...

Searches for the lepton number violating K^{+}→π^{-}μ^{+}e^{+} decay and the lepton flavor violating K^{+}→π^{+}μ^{-}e^{+} and π^{0}→μ^{-}e^{+} decays are reported using data collected by the NA62 experiment at CERN in 2017-2018. No evidence for these decays is found and upper limits of the branching ratios are obtained at 90% confidence level: B(K...

A bstract The NA62 experiment reports the branching ratio measurement $$ \mathrm{BR}\left({K}^{+}\to {\pi}^{+}\nu \overline{\nu}\right)=\left({10.6}_{-3.4}^{+4.0}\left|{}_{\mathrm{stat}}\right.\pm {0.9}_{\mathrm{syst}}\right)\times {10}^{-11} $$ BR K + → π + ν ν ¯ = 10.6 − 3.4 + 4.0 stat ± 0.9 syst × 10 − 11 at 68% CL, based on the observation of 2...

A bstract A search for the K ⁺ → π ⁺ X decay, where X is a long-lived feebly interacting particle, is performed through an interpretation of the K ⁺ → $$ {\pi}^{+}\nu \overline{\nu} $$ π + ν ν ¯ analysis of data collected in 2017 by the NA62 experiment at CERN. Two ranges of X masses, 0–110 MeV /c ² and 154–260 MeV /c ² , and lifetimes above 100 ps...

The NA62 experiment at CERN reports searches for K+→μ+N and K+→μ+νX decays, where N and X are massive invisible particles, using the 2016–2018 data set. The N particle is assumed to be a heavy neutral lepton, and the results are expressed as upper limits of O(10−8) of the neutrino mixing parameter |Uμ4|2 for N masses in the range 200–384 MeV/c2 and...

A bstract The NA62 experiment at the CERN SPS reports a study of a sample of 4 × 10 ⁹ tagged π ⁰ mesons from K ⁺ → π ⁺ π ⁰ ( γ ), searching for the decay of the π ⁰ to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4 . 4 × 10 − 9 is set on the branching ratio at 90% confidence level,...

A bstract The NA62 experiment reports an investigation of the $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ K + → π + ν ν ¯ mode from a sample of K ⁺ decays collected in 2017 at the CERN SPS. The experiment has achieved a single event sensitivity of (0 . 389 ± 0 . 024) × 10 − 10 , corresponding to 2.2 events assuming the Standard Model branching rat...

A search for heavy neutral lepton (N) production in K+→e+N decays using the data sample collected by the NA62 experiment at CERN in 2017–2018 is reported. Upper limits of the extended neutrino mixing matrix element |Ue4|2 are established at the level of 10−9 over most of the accessible heavy neutral lepton mass range 144–462 MeV/c2, with the assump...

The NA62 experiment at CERN reports a search for the lepton number violating decays K+→π−e+e+ and K+→π−μ+μ+ using a data sample collected in 2017. No signals are observed, and upper limits on the branching fractions of these decays of 2.2×10−10 and 4.2×10−11 are obtained, respectively, at 90% confidence level. These upper limits improve on previous...

A bstract The results of a search for π ⁰ decays to a photon and an invisible massive dark photon at the NA62 experiment at the CERN SPS are reported. From a total of 4.12 × 10 ⁸ tagged π ⁰ mesons, no signal is observed. Assuming a kinetic-mixing interaction, limits are set on the dark photon coupling to the ordinary photon as a function of the dar...

The integrated low-level trigger and data acquisition (TDAQ) system of the NA62 experiment at CERN is described. The requirements of a large and fast data reduction in a high-rate environment for a medium-scale, distributed ensemble of many different sub-detectors led to the concept of a fully digital integrated system with good scaling capabilitie...

The NA62 experiment at the CERN SPS reports the first search for K ⁺ →π ⁺ νν¯ using the decay-in-flight technique, based on a sample of 1.21×10 ¹¹ K ⁺ decays collected in 2016. The single event sensitivity is 3.15×10 ⁻¹⁰ , corresponding to 0.267 Standard Model events. One signal candidate is observed while the expected background is 0.152 events. T...

K^{+}\rightarrow\pi^{+}\nu\overline{\nu}$ is one of the theoretically cleanest meson decay where to look for indirect effects of new physics complementary to LHC searches. The NA62 experiment at CERN SPS is designed to measure the branching ratio of this decay with 10\% precision. NA62 took data in pilot runs in 2014 and 2015 reaching the final des...

A search for heavy neutral lepton production in K+ decays using a data sample collected with a minimum bias trigger by the NA62 experiment at CERN in 2015 is reported. Upper limits at the 10−7 to 10−6 level are established on the elements of the extended neutrino mixing matrix |Ue4|2 and |Uμ4|2 for heavy neutral lepton mass in the ranges 170–448 Me...

In this paper we present new results on upper limits for the search of Heavy Neutral Leptons (HNL) with data collected by NA48/2 (2003-2004), NA62-RK (2007) and NA62 (2015) CERN experiments. The data collected with different trigger configuration allow to search for both long and short living heavy neutrinos in the mass range below the kaon mass. I...

The IAEA has developed a liquid scintillator-based system for the non-destructive assay of ²³⁵U in fresh fuel assemblies. The fast neutron coincidence collar (FNCL) addresses current limitations in existing neutron coincidence counting techniques when measuring fuel containing burnable neutron poisons. Detection of fast neutrons rather than thermal...

NA62 is a fixed-target experiment at the CERN SPS dedicated to measurements of rare kaon decays. Such measurements, like the branching fraction of the K⁺ → π⁺ ν decay, have the potential to bring significant insights into new physics processes when comparison is made with precise theoretical predictions. For this purpose, innovative techniques have...

Among the meson decays, K→πνν‾ are the cleanest environment, from the theoretical point of view, where to search for new physics effects. The NA62 Experiment at CERN SPS aims to measure the BR(K+→π+νν‾) with a 10% precision by the end of 2018. It has been commissioned with technical runs in 2014 and 2015, and some preliminary results of the detecto...

The rare decay K+ → π+ v v is an excellent process to study the physics of flavour because of its very clean nature. The strong suppression to the Standard Model (SM) contributions and the remarkable theoretical precision of the SM rate makes this decay sensitive to possible new degrees of freedom. The NA62 experiment has been designed and built to...

The main goal of the NA62 experiment at CERN SPS is to measure the branching ratio of the ultra-rare K+→π+νν decay, collecting about 100 events in two years of data taking to test the Standard Model of Particle Physics. Readout uniformity of sub-detectors, scalability, efficient online selection and lossless high rate readout are key issues. The TE...

The primary goal of the NA62 experiment at CERN SPS is to measure the branching ratio (BR) of the decay K+ → φ+vv with ≈ 10% precision. The experimental method and detectors are described in the present paper. Selected results of the pilot run in 2014 are shown.

The NA62 experiment will begin taking data in 2015. Its primary purpose is a 10% measurement of the branching ratio of the ultrarare kaon decay $K^+ \to \pi^+ \nu \bar{ \nu }$, using the decay in flight of kaons in an unseparated beam with momentum 75 GeV/c.The detector and analysis technique are described here.

A Time to Digital Converter (TDC) based system, to be used for most sub-detectors in the high-flux rare-decay experiment NA62 at CERN SPS, was built as part of the NA62 fully digital Trigger and Data AcQuisition system (TDAQ), in which the TDC Board (TDCB) and a general-purpose motherboard (TEL62) will play a fundamental role. While TDCBs, housing...

The main goal of the NA62 experiment at CERN is to measure the branching ratio of the ultra-rare K+→π+νbar nu decay, collecting about 100 events to test the Standard Model of Particle Physics. Readout uniformity of sub-detectors, scalability, efficient online selection and lossless high rate readout are key issues. The TDCB and TEL62 boards are the...

The NA62 collaboration is building a new experiment tailored to measure the ultra-rare kaon decay π νν + → + K . The first physics run is planned in autumn 2014. This paper presents the detectors of the new experiment and reports on the status of construction as well as first results from the Technical Run in November 2012.

The NA62 experiment at the CERN SPS aims at measuring the branching ratio (BR) of the rare K+ → π+vv̄ decay, with a precision of ∼ 10%. This goal will be achieved after two years of data taking by collecting ∼ 1013 K+ decays in the fiducial volume. The K+ → π+vv̄ is a "golden mode" in flavor physics because of the precise theoretical prediction. Th...

A precision measurement of the ratio of the rates of kaon leptonic decays K± → e± v and K± → μ±v with the full minimum bias data sample collected with low intensity 75 GeV/c beam by the NA62 experiment at CERN in 2007-2008 is reported. The result, obtained by analyzing 150,000 reconstructed K ± → e± v candidates with 11% background contamination, h...

The branching ratio (BR) for the decay K^+ \to \pi^+\nu\bar{\nu} is a sensitive probe for new physics. The NA62 experiment at the CERN SPS will measure this BR to within about 10%. To reject the background from dominant kaon decays with final state photons, the large-angle photon vetoes (LAVs) must detect photons of energy as low as 200 MeV with an...

The main goal of the NA62 experiment at the CERN SPS is to measure the branching ratio of the ultra-rare K+→π+νν decay, collecting about 100 events in two years of data taking. The experiment puts stringent requirements on the trigger and data acquisition system: the efficient online selection of interesting events and loss-less readout at high...

The branching ratio for the decay $K^+ \to \pi^+\nu\bar{\nu}$ is sensitive to new physics; the NA62 experiment will measure it to within about 10%. To reject the dominant background from channels with final state photons, the large-angle vetoes (LAVs) must detect particles with better than 1 ns time resolution and 10% energy resolution over a very...

The branching ratio (BR) for the decay K^+ \rightarrow \pi^+ \nu \bar{\nu} is a sensitive probe for new physics. The NA62 experiment at the CERN SPS will measure this BR to within about 10%. To reject the dominant background from channels with final state photons, the large-angle vetoes (LAVs) must detect photons of energy as low as 200 MeV with an...

The NA62 experiment at CERN, aimed to measure branching fraction (O(10−10)), relies on a Neon based RICH detector for π/μ separation, time measurement and level 0 trigger. The experimental requirements for this detector are: a muon contamination in pion samples lower than 5×10−3 in the momentum range 15–35 GeV/c and a time resolution on the charged...

The main goal of the NA62 experiment is to measure the branching ratio of the K⁺ ¿ ¿⁺¿¿¿ decay, collecting O(100) events in two years of data taking. Efficient online selection of interesting events and loss-less readout at high rate will be key issues for such experiment. An integrated trigger and data acquisition system...