S. Venditti

CERN | CERN

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...

A sample of 1.69×107 fully reconstructed π0→γe+e- decay candidates collected by the NA48/2 experiment at CERN in 2003-2004 is analyzed to search for the dark photon (A') production in the π0→γA' decay followed by the prompt A'→e+e- decay. No signal is observed, and an exclusion region in the plane of the dark photon mass mA' and mixing parameter ε2...

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...

This paper presents the new readout system of the Liquid Krypton calorimeter detector, which is part of the NA62 experiment [1] veto system. The system is based on the new Calorimeter REAdout Module (CREAM) board, developed by CAEN under the supervision of the CERN NA62 group; it will be able to provide a very precise measurement of the electromagn...

The NA62 experiment at CERN Super Proton Synchrotron aims at studying ultra-rare decays of charged kaons for precise tests of the Standard Model. The complete experimental setup is being commissioned for the first physics data taking in the autumn of 2014. This paper presents the final design and implementation of the Level-0 trigger system of the...

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.

The NA62 experiment at the CERN SPS aims to measure the Branching Ratio of the ultra-rare decay , collecting about 100 events in two years of data taking with a signal to background ratio of 10:1. A hermetic photon veto system has been designed to efficiently reject the π0 background, one of the main background sources, and the 20-ton liquid krypto...

The NA48/2 Collaboration at CERN has accumulated and analysed unprecedented statistics of rare kaon decays in the $K_{e4}$ modes: $K_{e4}(+-)$ ($K^\pm \to \pi^+ \pi^- e^\pm \nu$) and $K_{e4}(00)$ ($K^\pm \to \pi^0 \pi^0 e^\pm \nu$) with nearly one percent background contamination. It leads to the improved measurement of branching fractions and deta...

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 NA62 experiment at CERN aims at measuring the K+ → π+νν̅ decay Branching Ratio (BR) with unprecedented precision, by collecting O(100) events with ∼10% background in 2 years' data-taking. In this paper the measurement strategy adopted by the NA62 collaboration is described, as well as all the main detectors. The trigger system, a crucial item f...

A study of the dynamics of the rare decay K ±→π ±γγ has been performed on a sample of 232 decay candidates, with an estimated background of 17.4 ± 1.1 events, collected by the NA62 experiment at CERN in 2007. The results are combined with those from a measurement conducted by the NA48/2 Collaboration at CERN. The combined model-independent branchin...

The NA48/2 experiment at CERN collected two data samples with minimum bias trigger conditions in 2003 and 2004. A measurement of the rate and dynamic properties of the rare decay K ± → π ±γγ from these data sets based on 149 decay candidates with an estimated background of 15.5 ± 0.7 events is reported. The model-independent branching ratio in the...

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...

A sample of 65210 K± → π0π0e±ν (Ke400) decay candidates with 1% background contamination has been collected in 2003-2004 by the NA48/2 collaboration at the CERN SPS. A study of the differential rate provides the first measurement of the hadronic form factor variation in the plane (Mππ2, Meν2) and brings evidence for a cusp-like structure in the dis...

The NA62 experiment [1] at CERN SPS (Super Proton Synchrotron) accelerator aims at studying Kaon decays with high precision. The high resolution Liquid Krypton (LKr) calorimeter, built for the NA48 [2] experiment, is a crucial part of the experiment photon-veto system; to cope with the new requirements, the back-end electronics of the LKr had to be...

The goal of the NA62 experiment at the CERN SPS is the measurement of the Branching Ratio of the very rare kaon decay K+→π+ ν bar nu with a 10% accuracy by collecting 100 events in two years of data taking. An efficient photon veto system is needed to reject the K+→π+ π0 background and a liquid krypton electromagnetic calorimeter will be used for t...

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 data collected by the NA48/2 collaboration in 2003/2004 allowed several high-statistics measurements concerning Kaon decays. In this talk the measurement of the form factors of the semileptonic decays K±→e±νπ0K±→e±νπ0 (Ke3) and K±→μ±νπ0K±→μ±νπ0 (Kμ3) is presented, and the results obtained are compared with those from previous experiments.

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...

A sample of more than one million (Ke4) decay candidates with less than one percent background contamination has been collected by the NA48/2 experiment at the CERN SPS in 2003-2004, allowing a detailed study of the decay properties. The branching ratio, inclusive of Ke4 decays, is measured to be with a total relative error of 0.8%. This measuremen...

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 NA62 experiment at CERN SpS collected a large sample of charged kaon decays with a low intensity beam and minimum bias trigger conditions in 2007. This allowed measurements of a number of rare decays that are difficult to address in conventional high intensity experiments with highly selective trigger conditions. In particular, large samples of...

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 NA48/2 experiment at CERN [1] collected similar to 18.10(9) charged kaon decays during the years 2003/4. Along with the primary goals of the collaboration, i.e., the measurement of the CP-violating asymmetry in the K-+/- -> pi(+/-)pi(+)pi(-) and K-+/- -> pi(+/-)pi(0)pi(0) channels, the collected data allowed to perform many other interesting an...

The NA48/2 experiment at CERN [1] collected ~18.109 charged kaon decays during the years 2003/4. Along with the primary goals of the collaboration, i.e. the measurement of the CP-violating asymmetry in the K+/--->pi+/-pi+pi- and K+/--->pi+/-pi0pi0 decays thanks to the simultaneous collection of K+ and K- events, the collected data allowed to perfor...

We report results from the analysis of the $\mbox {$\mbox { ($\mbox {$\mbox {) decay by the NA48/2 collaboration at the CERN SPS, based on the total statistics of 1.13 million decays collected in 2003–2004. The hadronic form factors in the S- and P-wave and their variation with energy are obtained. The phase difference between the S- and P-wave sta...

The main goal of the NA62 experiment is to measure the branching ratio of the K+→π+νν¯ 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 has been designed. Only the...

Three possible solutions for a system of large-angle vetoes (LAV) have been analyzed and tested in order to choose the best option for the NA62 experiment, expected to take data in 2011/12 at CERN. The rejection power assured by the veto system, whose goal is mainly to veto photons from the K+→π+π0 and K+→π+π0π0 decays, is a key-point to collect ˜1...

As first observed by the NA48/2 experiment at the CERN SPS, the π0π0 invariant mass (M00) distribution from K±→π±π0π0 decay shows a cusp-like anomaly at M00=2m+, where m+ is the charged pion mass. An analysis to extract the ππ scattering lengths in the isospin I=0 and I=2 states, a0 and a2, respectively, has been recently reported. In the present w...

We report on the measurement of the direct emission (DE) and interference (INT) terms of the K ±→π ±π 0γ decay by the NA48/2 experiment at the CERN SPS. From the data collected during 2003 and 2004 about 600k such decay candidates have been selected. The relative amounts of DE and INT with respect to the internal bremsstrahlung (IB) contribution ha...

The NA62 experiment at CERN SPS is aimed at measuring the rare decay . This poses very stringent requirements on the particle identification capabilities of the apparatus in order to reject the overwhelming K+→μ+ν and K+→π+π0 background. In particular, a π0 rejection at level of 10−8 is needed to complement the kinematical rejection of π+π0 events....

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...

We report the results from a study of the full sample of ∼6.031×107 K ±→π ± π 0 π 0 decays recorded by the NA48/2 experiment at the CERN SPS. As first observed in this experiment, the π 0 π 0 invariant mass (M 00) distribution shows a cusp-like anomaly in the region around M 00=2m +, where m + is the charged pion mass. This anomaly has been interpr...

A sample of 7253 K+/- -> pi(+/-)e(+)e(-)(gamma) decay candidates with 1.0% background contamination has been collected by the NA48/2 experiment at the CERN SPS, which allowed a precise measurement of the decay properties. The branching ratio in the full kinematic range was measured to be BR = (3.11 +/- 0.12) x 10(-7), where the uncertainty includes...

The latest results from the NA48/2 collaboration on charged kaon decays will be reviewed in this paper. The high statistics available, collected during 2003 and 2004 runs, allows the study of charged kaon decays up to branching ratios (BR) of similar to 10(-8). The status of the analyses of several radiative decays (K(+/-) -> pi(+/-)pi(0)gamma, K(+...

In this paper the recent results of the NA62 Collaboration in the field of kaon decays will be reviewed. The goals pursued using the data collected in the 2007 run will he exposed, as well as the experimental solutions devised for the future experiment on the study of the ultra-rare K(+) -> pi(+)nu(nu) over bar decay, expected to take data in 2010-...

The computation of pion scattering lengths a{sub 0}{sup 0} and a{sub 0}{sup 2} has been addressed in two independent analyses by the NA48/2 collaboration: the variation of the phase shift {delta} = {delta}{sub 0}{sup 0}-{delta}{sub 1}{sup 1} in K{sup {+-}}{yields}{pi}{sup {+-}}{pi}{sup {+-}}e{sup {+-}}{nu} (Ke4) decay and the fit of a cusp-like str...

The P326 experiment at the CERN SPS has been proposed with the purpose of measuring the branching ratio for the decay K⁺ rarrpi⁺nunu macrto within ~10%. The photon veto system must provide a rejection factor of 10⁸ for pideg decays. We have explored two designs for the large-angle veto detectors, one based on scinti...

We report the results from a study of the full sample of $~6.031 x 10^{7} K^{\pm} \to \pi^{\pm} \pi^{0} \pi^{0}$ decays recorded by the NA48/2 experiment at the CERN SPS. As first observed in this experiment, the $\pi^{0} \pi^{0}$ invariant mass (M_00) distribution shows a cusp-like anomaly in the region around $M_{00} = 2m_{+}$, where m_{+} is the...

As first observed by the NA48/2 experiment at the CERN SPS, the $\pi^{0}\pi^{0}$ invariant mass ($M_{00}$) distribution from $K^{\+-} -> \pi^{+-}\pi^{0}\pi^{0}$ decay shows a cusp-like anomaly at $M_{00}=2m_{+}$, where $m_+$ is the charged pion mass. An analysis to extract the $\pi\pi$ scattering lengths in the isospin $I=0$ and $I=2$ states, $a_0$...

A sample of 7253 $K^\pm\to\pi^\pm e^+e^-(\gamma)$ decay candidates with 1.0% background contamination has been collected by the NA48/2 experiment at the CERN SPS, allowing a precise measurement of the decay properties. The branching ratio in the full kinematic range was measured to be ${\rm BR}=(3.11\pm0.12)\times 10^{-7}$, where the uncertainty in...

A sample of 3120 $K^\pm\to\pi^\pm\mu^+\mu^-$ decay candidates with $(3.3\pm0.7)$% background contamination has been collected by the NA48/2 experiment at the CERN SPS, allowing a detailed study of the decay properties. The branching ratio was measured to be ${\rm BR}=(9.62\pm0.25)\times 10^{-8}$. The form factor $W(z)$, where $z=(M_{\mu\mu}/M_K)^2$...

A precision test of lepton flavour universality has been performed by measuring the ratio RK of kaon leptonic decay rates K+ --> e+nu and K+ --> mu+nu in a sample of 59813 reconstructed K+ --> e+nu candidates with (8.71 +- 0.24)% background contamination. The result RK = (2.487 +- 0.013) * 10^{-5} is in agreement with the Standard Model expectation...