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.
A precise measurement of the vector and axial-vector form factors difference Formula omitted in the Formula omitted decay is presented. About 95K events of Formula omitted are selected in the OKA ...experiment. The result is Formula omitted. Both errors are smaller than in the previous Formula omitted measurements.
A high statistics data sample of the decays of Formula omitted 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 Formula omitted decays with the energy of the photon in the kaon rest frame greater than 30 MeV. The measured branching fraction of the Formula omitted, with Formula omitted is equal to Formula omitted. The measured differential branching fraction over photon energy is compared with the prediction of the chiral perturbation theory to Formula omitted. A search for an up-down asymmetry of the photon with respect to the hadronic system decay plane is also performed.
On the statistics of ~1.7 × 10
8
interactions of positively charged kaons on copper nuclei, coherent events of the
K
+
π
0
system production are selected. The cross sections for the Coulomb and ...coherent strong components and their interference in the region of the
K
*(892) meson are measured. The partial width for the decay
K
*(892) →
K
+
γ is determined. When studying the mass spectrum of the
K
+
π
0
system, an effect which can be interpreted as the interference of the chiral anomaly and the
K
*(892)
s
-channel amplitudes is found. This gives an estimate for the ratio of the observed amplitude of the chiral anomaly to the theoretical one:
A
exp
/
A
th
= 0.9 ± 0.24(stat.) ± 0.3(syst.).
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, Letnik:
78, Številka:
2
Journal Article
Recenzirano
Odprti dostop
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.
Study of [Formula omitted] 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
Results of a study of the Formula omitted 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 Formula omitted decay are calculated for different cuts on Formula omitted and Formula omitted. In particular, the branching ratio for Formula omitted MeV and Formula omitted is measured R = Formula omitted = = (0.587±0.010(stat.)±0.015(syst.)) Formula omitted, which is in a good agreement with ChPT Formula omitted calculations.
In a sample of ∼5 × 10{sup 9} positive kaon collisions with copper nuclei, the events of coherent production of K{sup +}π{sup 0} pairs are selected, the contributions of the Coulomb and strong ...production mechanisms are discriminated, and the corresponding cross sections are determined. The phase shift difference between the Coulomb and strong amplitudes is obtained.
Abstract
Results of a study of the
$$K^+ \rightarrow \pi ^{0} e^{+} \nu \gamma $$
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
$$K_{e3}$$
K
e
3
decay are calculated for different cuts on
$$E^*_\gamma $$
E
γ
∗
and
$$cos\Theta ^{*}_{e\gamma }$$
c
o
s
Θ
e
γ
∗
. In particular, the branching ratio for
$$E^{*}_{\gamma }>30$$
E
γ
∗
>
30
MeV and
$$\Theta ^{*}_{e \gamma }>20^{\circ }$$
Θ
e
γ
∗
>
20
∘
is measured R =
$$\frac{Br(K^+ \rightarrow \pi ^{0} e^{+} \nu _{e} \gamma ) }{Br(K^+ \rightarrow \pi ^{0} e^{+} \nu _{e})} $$
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
.))
$$\times 10^{-2}$$
×
10
-
2
, which is in a good agreement with ChPT
$$O(p^{4})$$
O
(
p
4
)
calculations.
Abstract Results of a study of the $$K^+ \rightarrow \pi ^{0} e^{+} \nu \gamma $$ 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 $$K_{e3}$$ K e 3 decay are calculated for different cuts on $$E^*_\gamma $$ E γ ∗ and $$cos\Theta ^{*}_{e\gamma }$$ c o s Θ e γ ∗ . In particular, the branching ratio for $$E^{*}_{\gamma }>30$$ E γ ∗ > 30 MeV and $$\Theta ^{*}_{e \gamma }>20^{\circ }$$ Θ e γ ∗ > 20 ∘ is measured R = $$\frac{Br(K^+ \rightarrow \pi ^{0} e^{+} \nu _{e} \gamma ) }{Br(K^+ \rightarrow \pi ^{0} e^{+} \nu _{e})} $$ 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.)) $$\times 10^{-2}$$ × 10 - 2 , which is in a good agreement with ChPT $$O(p^{4})$$ O ( p 4 ) calculations.
In a sample of ∼5 × 10
9
positive kaon collisions with copper nuclei, the events of coherent production of
K
+
π
0
pairs are selected, the contributions of the Coulomb and strong production ...mechanisms are discriminated, and the corresponding cross sections are determined. The phase shift difference between the Coulomb and strong amplitudes is obtained.
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