A large sample of charged kaon decays in 2007 has been collected by the NA62 experiment at CERN SPS using the experimental setup of the former NA48 experiment. Its intense kaon beam provides an ...abundant source of tagged neutral pions in vacuum. A measurement of the electromagnetic transition form factor slope of the neutral pion from 1:05 × 106 fully reconstructed π0 Dalitz decays is presented. The obtained preliminary value a = (3.70 ± 0.53stat ± 0.36syst) × 10−2 is the first 5.8σ observation of a non-zero slope in the time-like region of momentum transfer. K+ → π+ vv̄ is a theoretically very clean decay where indirect effects of new physics may be detectable. The NA62 apparatus has been significantly upgraded between 2008 and 2014 in order to measure the branching ratio of this decay with 10% precision. The NA62 experiment took data with the new setup in pilot runs in 2014 and 2015, reaching the design beam intensity. Results of first data quality studies in view of the 2016-2017 physics runs are presented.
A measurement of the K+→π0e+νγ radiative decay and a search for the K+→π−(π0)e+e+ lepton number violating decays by the NA62 experiment are presented, together with the first observation and ...branching fraction measurement of the rare decay K+→π0π0μ+ν by the NA48/2 experiment.
Diamond sensors provide a promising radiation hard solution to the challenges posed by the future experiments at hadron machines. A 3D geometry with thin columnar resistive electrodes orthogonal to ...the diamond surface, obtained by laser nanofabrication, is expected to provide significantly better time resolution with respect to the extensively studied planar diamond sensors. We report on the development, production, and characterisation of innovative 3D diamond sensors achieving 30% improvement in both space and time resolution with respect to sensors from the previous generation. This is the first complete characterisation of the time resolution of 3D diamond sensors and combines results from tests with laser, β rays and high energy particle beams. Plans and strategies for further improvement in the fabrication technology and readout systems are also discussed.
The RICH detector of the NA62 experiment at CERN SPS is required to suppress \(\mu^+\) contamination in \(K^+ \to \pi^+ \nu \bar\nu\) candidate events by a factor at least 100 between 15 and 35 GeV/c ...momentum, to measure the pion arrival time with \(\sim 100\) ps resolution and to produce a trigger for a charged track. It consists of a 17 m long tank filled with Neon gas at atmospheric pressure. Čerenkov light is reflected by a mosaic of 20 spherical mirrors placed at the downstream end of the vessel and is collected by 1952 photomultipliers placed at the upstream end. The construction of the detector will be described and the performance reached during first runs will be discussed.
Recent results of an aging test performed at the CERN Gamma Irradiation Facility on a single-gap RPC prototype developed for the LHCb Muon System are presented. The results are based on an ...accumulated charge of about
0.45
C/cm
2
, corresponding to about 4 years of LHCb running at the highest background rate. The performance of the chamber has been studied, under several photon flux values, exploiting a muon beam. A degradation of the rate capability above
1
kHz/cm
2
is observed, which can be correlated to a sizeable increase of resistivity of the chamber plates. An increase of the chamber dark current is also observed. The chamber performance is found to fulfill the LHCb operation requirements.
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