A brief review of recent results on neutrino oscillations from accelerator and reactor experiments is presented. Emphasis is placed on the indication of CP violation in neutrino oscillations obtained ...in long-baseline accelerator experiments. The latest results of a search for a sterile neutrino are discussed and the nearest-term prospects for long and short-baseline oscillation experiments are outlined.
Observation of K+→π+π0π0γ decay Artamonov, A. V.; Bychkov, V. N.; Donskov, S. V. ...
The European physical journal. C, Particles and fields,
04/2024, Letnik:
84, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The
K
+
→
π
+
π
0
π
0
γ
decay is observed by the OKA collaboration. About 60 events of the decay observed with signal:noise
≈
1
. The branching ratio obtained by normalization to
K
+
→
π
+
π
0
π
0
is ...measured to be
(
3.7
±
0.9
(
s
t
a
t
)
±
0.3
(
s
y
s
t
)
)
×
10
-
6
for
E
γ
∗
>
10
MeV
. The branching ratio,
γ
energy spectrum and angular distribution are consistent with ChPT prediction.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A high-statistics data sample of the
K
+
decays is recorded by the OKA collaboration. A missing mass analysis is performed to search for a light invisible pseudoscalar axion-like particle (ALP)
a
in ...the decay
K
+
→
π
+
π
0
a
. No signal is observed, and the upper limits for the branching ratio of the decay are calculated. The
90
%
confidence level upper limit changes from
2.5
·
10
-
6
to
2
·
10
-
7
for the ALP mass from 0 to 200 MeV/
c
2
, except for the region of
π
0
mass, where the upper limit is
4.4
·
10
-
6
.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
—
The parameters of scintillator veto detectors that should be installed in an intermediate water Cherenkov detector of the Hyper-Kamiokande project have been measured. The veto detectors are disc ...scintillators with embedded wavelength-shifting fibers and with compact photosensors, i.e., silicon photomultipliers. It is shown that the detection efficiency of these detectors for cosmic muons is larger than 99%.
Recent results from long-baseline neutrino experiments are presented. Prospects for determining the mass hierarchy and observing CP violation in neutrino oscillations are discussed.
Study of K+→π0e+νγ decay with OKA setup Polyarush, A. Yu; Akimenko, S. A.; Artamonov, A. V. ...
The European physical journal. C, Particles and fields,
02/2021, Letnik:
81, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Results of a study of the
K
+
→
π
0
e
+
ν
γ
decay at OKA setup are presented. More than 32,000 events of this decay are observed. The differential spectra over the photon energy and the ...photon–electron opening angle in kaon rest frame are presented. The branching ratios, normalized to that of
K
e
3
decay are calculated for different cuts on
E
γ
∗
and
c
o
s
Θ
e
γ
∗
. In particular, the branching ratio for
E
γ
∗
>
30
MeV and
Θ
e
γ
∗
>
20
∘
is measured R =
B
r
(
K
+
→
π
0
e
+
ν
e
γ
)
B
r
(
K
+
→
π
0
e
+
ν
e
)
= = (0.587±0.010(
stat
.)±0.015(
syst
.))
×
10
-
2
, which is in a good agreement with ChPT
O
(
p
4
)
calculations.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The neutrino on-axis and off-axis beam was studied in the near neutrino detector of the longbaseline experiment T2K: beam composition, long-term stability, and spatial asymmetry.
Totally active and magnetic segmented scintillation neutrino detectors are developed for the nextgeneration accelerator neutrino experiments. Such detectors will incorporate scintillation modules ...with scintillation counters that form
X
and
Y
planes. A single counter is a 7 × 10 × 90 mm
3
scintillation bar with gluedin wavelength-shifting fibers and micropixel avalanche photodiodes. The results of measurements of the parameters of these detectors are presented.
The T2K (Tokai-to-Kamioka) experiment is a long baseline neutrino oscillation experiment designed to probe the
θ
13
neutrino mixing parameter by looking for the appearance of
ν
e
in an almost pure
ν
...μ
beam. The concurrent measurement of the
ν
μ
disappearance allows refined measurements of the atmospheric Δ
m
2
and
θ
23
mixing parameters.
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