A precision measurement of the ratio RK of the rates of kaon leptonic decays K±→e±ν and K±→μ±ν with the full data sample collected by the NA62 experiment at CERN in 2007–2008 is reported. The result, ...obtained by analysing ∼150000 reconstructed K±→e±ν candidates with 11% background contamination, is RK=(2.488±0.010)×10−5, in agreement with the Standard Model expectation.
The development of a single-photon detector based on a vacuum tube, transmission photocathode, microchannel plate and CMOS pixelated read-out anode is presented. This imager will be capable of ...detecting up to 1 billion photons per second over an area of 7 cm
2
, with simultaneous measurement of position and time with resolutions of about 5 microns and few tens of picosecond, respectively. The detector has embedded pulse-processing electronics with data-driven architecture, based on the Timepix4 ASIC, producing up to 160 Gb/s data that will be handled by a high-throughput FPGA-based external electronics and data acquisition system. These performances will enable significant advances in particle physics, life sciences, quantum optics or other emerging fields where the detection of single photons with excellent timing and position resolutions are simultaneously required.
A measurement of the K+→ π+μ+μ− decay Cortina Gil, E.; Kleimenova, A.; Minucci, E. ...
The journal of high energy physics,
11/2022, Letnik:
2022, Številka:
11
Journal Article
Recenzirano
Odprti dostop
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
).
A
bstract
The NA62 experiment at CERN, designed to study the ultra-rare decay
K
+
→
π
+
ν
ν
¯
, has also collected data in beam-dump mode. In this configuration, dark photons may be produced by ...protons dumped on an absorber and reach a decay volume beginning 80 m downstream. A search for dark photons decaying in flight to
μ
+
μ
−
pairs is reported, based on a sample of 1
.
4 × 10
17
protons on dump collected in 2021. No evidence for a dark photon signal is observed. A region of the parameter space is excluded at 90% CL, improving on previous experimental limits for dark photon masses between 215 and 550 MeV
/c
2
.
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