A precision test of lepton flavour universality has been performed by measuring the ratio RK of kaon leptonic decay rates K+→e+ν and K+→μ+ν in a sample of 59 813 reconstructed K+→e+ν 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.
The NA62 experiment collected a large sample of charged kaon decays in 2007 with a highly efficient trigger for decays into electrons. A measurement of the π0 electromagnetic transition form factor ...slope parameter from 1.11×106 fully reconstructed K±→π±πD0, πD0→e+e−γ events is reported. The measured value a=(3.68±0.57)×10−2 is in good agreement with theoretical expectations and previous measurements, and represents the most precise experimental determination of the slope in the time-like momentum transfer region.
Construction and test of a RICH prototype for the NA62 experiment Anzivino, G.; Biino, C.; Bizzeti, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2008, Volume:
593, Issue:
3
Journal Article
Peer reviewed
Open access
A RICH prototype has been constructed and tested. The detector was cylindrical, 17
m long and 60
cm diameter, filled with neon gas at atmospheric pressure. A spherical mirror with 17
m focal length ...was used and 96 photomultipliers were placed in the mirror focal plane. The prototype was exposed to a
200
GeV
/
c
momentum negative beam derived from the CERN SPS in the 2007 fall. The performances of the detector in terms of Cherenkov angle resolution, number of photoelectrons and time resolution are presented.
The trigger and DAQ system for the NA62 experiment Avanzini, C.; Collazuol, G.; Galeotti, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Volume:
623, Issue:
1
Journal Article
Peer reviewed
Open access
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 very first trigger stage will be implemented in hardware, in order to reduce the total rate for the software levels on PC farms. Readout uniformity among different subdetectors and scalability were taken into account in the architecture design.
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.
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
+
→
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 are considered. The limits set on the branching ratio, BR(
K
+
→
π
+
X
), are competitive with previously reported searches in the first mass range, and improve on current limits in the second mass range by more than an order of magnitude.
Performance of the NA62 RICH detector Pepe, M.; Aisa, D.; Anzivino, G. ...
2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC),
2015-Oct.
Conference Proceeding
NA62 is the last generation kaon experiment at CERN SPS aiming to study the decay K + _ π + νν̅. The goal of the experiment is to measure the decay branching ratio (O(10 -10 )) with 10% accuracy, ...collecting about 100 K + → π + νν̅ events in three years of data taking and assuming a 10% signal acceptance. The NA62 detector must be able to reject background events from decay channels with branching ratios up to 10 orders of magnitude higher than the signal and with similar experimental signature. To this purpose, good Particle Identification (PID) and kinematic rejection are required. Precise timing is also needed to correctly associate the π + with the parent K + in a high rate environment. The key element of the PID in NA62 is the Ring Imaging CHerenkov detector (RICH) to identify π and μ in the momentum range between 15 and 35 GeV/c with a muon rejection factor better than 1%; it is also required to measure the pion arrival time with a precision better than 100 ps and the Cherenkov angle with a resolution better than 80 μ rad. Finally, it must provide a fast L0 trigger signal for charged particles. At the beginning of the NA62 pilot run, from mid October to mid December 2014, the RICH detector was completely installed and ready to take data. The installation details and the results on the detector performance will be presented together with preliminary results from the first NA62 physics run in 2015.
A measurement of the K+→ π+μ+μ− decay Cortina Gil, E.; Kleimenova, A.; Minucci, E. ...
The journal of high energy physics,
11/2022, Volume:
2022, Issue:
11
Journal Article
Peer reviewed
Open access
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 of the squared dimuon mass. A measurement of the form factor parameters and their uncertainties is performed using a description based on Chiral Perturbation Theory at
O
(
p
6
).
PDF
