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, Volume:
84, Issue:
4
Journal Article
Peer reviewed
Open access
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.
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
.
In this work, the process of decomposition of 2,4-dichlorophenol (2,4-DCP) vapor under the influence of atmospheric pressure DBD in oxygen was studied. The studies were carried out in two modes: with ...a catalyst (natural vermiculite doped with zirconium) and without it. A number of basic characteristics of the catalyst were assessed. The rates and effective rate constants of sorption processes, as well as decomposition processes in plasma and plasma-catalytic systems, were determined. Based on these data, the energy efficiency of the decomposition process was calculated. The data obtained suggested that the initial stage of decomposition is the reaction of interaction of electrons with pollutant molecules. The catalyst has been shown to speed up the decomposition process, increase energy efficiency and the conversion of 2,4-DCP to CO
2
molecules, and prevent the formation of condensed products on the reactor walls. The work estimates the carbon and chlorine balances before and after treatment, which reach a maximum of 99 and 60%, respectively. It was also shown that the catalyst retains its activity for at least 7 h of continuous operation.
Curd whey is a valuable secondary raw material of the dairy industry. Most of the whey is drained as a waste product, which causes not only economic but also environmental damage. Therefore, the ...effective technologies development for the curd whey processing is the dairy industry actual task. The present work purpose is to select the effective modes of the whey freezing-out for extracting its valuable components. In experimental studies, the capacitive type cryoconcentrator was used, in which ice is frozen on the inner cylindrical surface. Experiments were made on curd whey separating freezing-out at the crystallizer heat-exchange surface different temperatures. It was found that with a decrease in the freezing rate the loss of dry substances decreases and the cryoconcentration process is more efficient. The protein precipitate is observed during the process of whey freezing-out at the bottom of the crystallizer. This phenomenon was studied and the additional experiments were made in order to select the most favorable modes. It was found that the protein precipitate largest amount is observed at 1.5 degrees temperature differential and the heat-exchange surface temperature is minus 2°C. Under indicated modes about 2.0-2.1 g/100 g of protein precipitate falls at the bottom of the container.
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, Volume:
81, Issue:
2
Journal Article
Peer reviewed
Open access
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.
The work investigates the effect of mechanochemical activation (MCA) on the structure and properties of vermiculite. The process of activation is controlled by X–ray diffraction (XRD), ...IR–spectroscopy, and scanning electron microscopy. The thermal stability of the vermiculite was studied by the differential thermal analysis. It was found that an increase in the degree of MCA of vermiculite makes it possible to change the vermiculite hydration states and its mica package passed into a zero hydration state, one– or two–layer state. In the study of the samples sorption capacity as related to oil products, it was shown that adsorption proceeded according to a competitive mechanism. The linearization of experimental data on the adsorption of oil products was achieved in linear coordinates of the Freundlich isotherm, that confirmed adsorption in the volume of energetically inhomogeneous porous adsorbent. A positive effect of MCA on the sorption capacity of the samples was noted.
Display omitted
•In the process of mechanochemical activation of vermiculite, the processes associated with dispersion and stratification of the mica package of the mineral were observed, an increase in the degree of mechanochemical effect on vermiculite allows to change its hydration states, contributing to the transition toward a zero hydration, one– or two–layer state.•Mechanochemical activation of the samples does not only change the phase structure of vermiculite, but also significantly changes its physicochemical properties, contributing to the growth of acid–base sites on the surface, specific surface area.•A positive effect of mechanochemical activation on the sorption capacity of samples based on modified vermiculite in relation to oil products was noted.
The
T
-odd correlation
, which is the mixed product of the momenta of
,
, and γ in the system of rest of the kaon divided by
, has been measured in the
K
+
→ π
0
e
+
ν
e
γ radiative decay among 101 ...200 candidate events detected at the OKA setup. The asymmetry of the distribution in
is characterized by the ratio
, where
is the number of events with positive (negative) ξ. The value
= (+0.1 ± 3.9(stat.) ± 1.7(syst.)) × 10
–3
or
(90% C.L.) has been obtained.
Abstract A high statistics data sample of the decays of $$K^+$$ K+ mesons to three charged particles was accumulated by the OKA experiment in 2012 and 2013. This allowed to select a clean sample of ...about 450 events with $$K^{+}\rightarrow \pi ^{+}\pi ^{-}\pi ^{+}\gamma $$ K+→π+π-π+γ decays with the energy of the photon in the kaon rest frame greater than 30 MeV. The measured branching fraction of the $$K^{+}\rightarrow \pi ^{+}\pi ^{-}\pi ^{+}\gamma $$ K+→π+π-π+γ , with $$E_{\gamma }^{*} > 30\ \hbox {MeV}$$ Eγ∗>30MeV is equal to $$(0.71 \pm 0.05) \times 10^{-5}$$ (0.71±0.05)×10-5 . The measured differential branching fraction over photon energy is compared with the prediction of the chiral perturbation theory to $${\mathcal {O}}(p^{4})$$ O(p4) . A search for an up-down asymmetry of the photon with respect to the hadronic system decay plane is also performed.
Search for heavy neutrino in K+→μ+νH decay Sadovsky, A. S.; Kurshetsov, V. F.; Filin, A. P. ...
The European physical journal. C, Particles and fields,
02/2018, Volume:
78, Issue:
2
Journal Article
Peer reviewed
Open access
A high statistics data sample of the
K
+
→
μ
+
ν
μ
decay was accumulated by the OKA experiment in 2012. The missing mass analysis was performed to search for the decay channel
K
+
→
μ
+
ν
H
with a ...hypothetic stable heavy neutrino in the final state. The obtained missing mass spectrum does not show peaks that could be attributed to existence of stable heavy neutrinos in the mass range
(
270
<
m
ν
H
<
375
)
MeV
/
c
2
. As a result, upper limits on the branching ratio and on the value of the mixing element
|
U
μ
H
|
2
are obtained.
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