Several radiative decays are under study by OKA setup at U-70 synchrotron. First, the radiative decay K+ → µ+νγ(Kµ2γ) is studied on statistics of about 95K events for 25 MeV < Eγ* < 150 MeV. A clear ...destructive interference between bremsstrahlung and structure dependent SD− term is observed. As a result, the vector and axial-vector form factors difference is measured: FV − FA = 0.134 ± 0.021(stat.) ± 0.027(syst.) which is 2.3 σ away fromχP T O(p4). Moreover, the decay K+ → π+π−π+γ is studied on statistics of about 450 events for 30 Mev < Eγ* < 70 Mev. The total and differential branching fractions of the decay are measured. Br(K+ → π+π−π+γ) = (7.1±0.4(stat.)±0.3(syst.))·10−6 to be compared withχP T O(p4) (6.65 ± 0.05) · 10−6. In addition, a search for an up-down photon asymmetry with respect to the hadronic system decay plane is performed.
Some recent results from OKA setup are presented. First, the decay K + →π0 e+υ(K e3) is studied. About 3.15M events are selected for the analysis. The linear and quadratic slopes for the decay ...formfactor f +(t) are measured: λ ′ + = ( 26.1 ± 0.45 ± 0.38 ) × 10 − 3 , λ ″ + = ( 1.94 ± 0.23 ± 0.12 ) × 10 − 3 . For the exotic scalar and tensor interactions we get: FS /f +(0) = (−0.44±0.7±0.24) × 10−2; FT /f +(0) = (0.16±2±1.3) × 10−2. Several alternative parametrizations are tried: the Pole fit parameter is found to be MV = 890 ± 3.7 MeV; the parameter of the Dispersive parametrization is measured to be Λ+ = (24.72 ± 0.23) × 10−3. Second, the results of a search for heavy neutrino in the K μ2 decay are shown. The upper limits on the mixing parameter of the heavy neutrino with the muon neutrino |U μH |2 are obtained. Typically, |U μH |2 ≤ 10−6 for the region 225 ≤ mH ≤ 375 MeV. Third, a new study of the radiative K μ3 decay are presented. The number of signal events is ∼ 580 which is 4 times larger than in previous measurements. R = B r ( K μ 3 γ + , 30 < E γ < 60 M e V ) / B r ( K μ 3 ) = ( 4.85 ± 0.2 ( s t a t ) ± 0.5 ( s y s t ) ) × 10 − 4 which should be compared with 4.7 × 10−4 from the theory. An estimate of the T-odd asymmetry gives A ξ = (−0.19±0.05±0.09). A space asymmetry over c o s ( θ μ γ * ) , where θ μ γ * is the angle between photon and muon momenta in the kaon rest frame is measured to be A(cosθ*) = 0.6±0.05±0.1.
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.
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
.
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 article offers a brief overview of the main theoretical and practical results obtained by its authors and their scientific followers. The results concern mainly the deterministic theory of ...pattern recognition. In particular, the main results on the logical and algebraic correction of heuristic algorithms are presented. Possible directions for the development of recognition algorithms based on inductive inference, similarity, and precedence metrics are also proposed. The practical part deals with some of the decision-making tasks in areas such as medical diagnostics and various technical areas. The nature of the review and value judgments is based on the experience of the authors.
Abstract
The authors assess the influence of meteorological factors on the yield of Festulolium seeds. The analysis of weather conditions over 12 years shows that precipitation during the growing ...season of Festulolium in the second year of vegetation closely correlates with seed yield (r = 0.85). The relationship between the yield and the amount of precipitation over the growing season is expressed by the regression equation: Y = 190.52 + 3.2894x
1
. The yield was closely correlated with the HTC (r = 0.80). This relationship can be expressed by the following equation: Y = 189.91 + 562.8x
2
. It is found that the optimal conditions for Festulolium seed yield formation arise when at least 147 mm of precipitation falls within the growing season (mostly during the period from aftergrowth to flowering), the hydrothermal coefficient is 0.8-1.7, the average daily temperature is within 17-19°C in the flowering phase and 18-21°C during the period of seed formation-ripening, and the proportion of days without precipitation in the flowering phase is at least 57%.
Abstract
The presented research is the first to study the fodder productivity, nutritive and energy value of new varieties of Festulolium of different morphotypes in the conditions of the ...forest-steppe of the Central Chernozem Region of Russia. In the green mass of the studied varieties crude protein content was quite low ranging from 6.2 to 9.7%, which was 1.4-2.3 times lower than required by zootechnical norms for cattle feeding. The studied varieties of Festulolium were distinguished by a rather high content of soluble sugars, which was 14.7-19.4%. The Viknel variety contained more digestible protein (68.74-76.01 g), but this value did not differ much from other varieties, in which it ranged from 64.78 to 72.47 g/kg of green mass. Among the studied varieties of Festulolium the highest yield of green mass was obtained in the second and third years of grass stand life. Productivity of the Izumrudnyi fescue-type mowing variety reached 40.31-44.09 t/ha, which was 1.3-1.9 times higher than that of ryegrass-type mowing-and-grazing varieties, the yield of which was 23.07-31.24 t/ha.
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.
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