The design of a new digitally programmable analogue circuit well suited for the implementation of several sets of nonlinear functions by approximating them by using a linear combination of sigmoidal ...terms is presented. The proposed circuit, allowing the building of several collections of nonlinear functions, would be useful in modelling artificial neural networks, fuzzy as well as partial differential equations based circuits.
Abstract The NA62 experiment reports the branching ratio measurement BR K + → π + ν ν ¯ = 10.6 − 3.4 + 4.0 stat ± 0.9 syst × 10 − 11 $$ \mathrm{BR}\left({K}^{+}\to {\pi}^{+}\nu ...\overline{\nu}\right)=\left({10.6}_{-3.4}^{+4.0}\left|{}_{\mathrm{stat}}\right.\pm {0.9}_{\mathrm{syst}}\right)\times {10}^{-11} $$ at 68% CL, based on the observation of 20 signal candidates with an expected background of 7.0 events from the total data sample collected at the CERN SPS during 2016–2018. This provides evidence for the very rare K + → π + ν ν ¯ $$ {\pi}^{+}\nu \overline{\nu} $$ decay, observed with a significance of 3.4σ. The experiment achieves a single event sensitivity of (0.839 ± 0.054) × 10 −11, corresponding to 10.0 events assuming the Standard Model branching ratio of (8.4 ± 1.0) × 10 −11. This measurement is also used to set limits on BR(K + → π + X), where X is a scalar or pseudo-scalar particle. Details are given of the analysis of the 2018 data sample, which corresponds to about 80% of the total data sample.
The NA62 experiment at CERN collected a large sample of charged kaon decays in ight with a minimum bias trigger in 2007. Upper limits on the rate of the charged kaon decay into a muon and a heavy ...neutral lepton (HNL) obtained from this data are reported for a range of HNL masses. The NA62 experiment has collected further data in 2015 with a completely new and improved detector. New limits on heavy neutrinos from kaon decays into electron and HNL will be presented.
Abstract The NA62 experiment reports an investigation of the K + → π + ν ν ¯ $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ 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 ratio of (8.4 ± 1.0) × 10 −11. Two signal candidates are observed with an expected background of 1.5 events. Combined with the result of a similar analysis conducted by NA62 on a smaller data set recorded in 2016, the collaboration now reports an upper limit of 1.78 × 10 −10 for the K + → π + ν ν ¯ $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ branching ratio at 90% CL. This, together with the corresponding 68% CL measurement of ( 0.48 − 0.48 + 0.72 $$ {0.48}_{-0.48}^{+0.72} $$ ) × 10 −10, are currently the most precise results worldwide, and are able to constrain some New Physics models that predict large enhancements still allowed by previous measurements.
A
bstract
The NA62 experiment reports an investigation of the
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 ratio of (8
.
4
±
1
.
0)
×
10
−
11
. Two signal candidates are observed with an expected background of 1.5 events. Combined with the result of a similar analysis conducted by NA62 on a smaller data set recorded in 2016, the collaboration now reports an upper limit of 1
.
78
×
10
−
10
for the
K
+
→
π
+
ν
ν
¯
branching ratio at 90% CL. This, together with the corresponding 68% CL measurement of (
0.48
−
0.48
+
0.72
)
×
10
−
10
, are currently the most precise results worldwide, and are able to constrain some New Physics models that predict large enhancements still allowed by previous measurements.
Data Preparation for NA62 Laycock, Paul
EPJ Web of Conferences,
2019, Letnik:
214
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
In 2017, NA62 recorded over a petabyte of raw data, collecting around a billion events per day of running. Data are collected in bursts of 3-5 seconds, producing output files of a few gigabytes. A ...typical run, a sequence of bursts with the same detector configuration and similar experimental conditions, contains 1500 bursts and constitutes the basic unit for offline data processing. A sample of 100 random bursts is used to make timing calibrations of all detectors, after which every burst in the run is reconstructed. Finally the reconstructed events are filtered by physics channel with an average reduction factor of 20, and data quality metrics are calculated.
Initially a bespoke data processing solution was implemented using a simple finite state machine with limited production system functionality. In 2017, the ATLAS Tier-0 team offered the use of their production system, together with the necessary support. Data processing workflows were rewritten with better error-handling and I/O operations were minimised, the reconstruction software was improved and conditions data handling was changed to follow best practices suggested by the HEP Software Foundation conditions database working group. This contribution describes the experience gained in using these tools and methods for data-processing on a petabyte scale experiment.
The results of a search for π0 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 × 108 tagged π0 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 dark photon mass, improving on previous searches in the mass range 60–110 MeV/c2. The present results are interpreted in terms of an upper limit of the branching ratio of the electro-weak decay π0→γνν¯\ {\pi}^0\to \gamma \nu \overline{\nu} \, improving the current limit by more than three orders of magnitude.
The design of a multi-chip architecture can be an appealing solution to implement very large Artificial Neural Networks systems. The size of these systems often can be a only way to deeply and ...effectively investigate on innovative, "bioinspired", computational paradigms. In this paper, the authors present the architecture of a system with two analogue chips well suited to carry out a large Integrate and Fire Neural Network electronic system. In particular, the chips have been designed by using a dedicated technique to reduce the I/O analogue pins.
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