Study of decay with OKA setup

A. Yu. Polyarush; S. A. Akimenko; A. V. Artamonov; A. M. Blik; V. S. Burtovoy; V. N. Bychkov; S. V. Donskov; V. A. Duk; A. P. Filin; S. N. Filippov; A. M. Gorin; E. N. Gushchin; A. V. Inyakin; G. D. Kekelidze; G. V. Khaustov; S. A. Kholodenko; A. A. Khudyakov; V. N. Kolosov; V. I. Kravtsov; Yu. G. Kudenko; V. F. Kurshetsov; V. A. Lishin; V. M. Lysan; M. V. Medynsky; Yu. V. Mikhailov; V. F. Obraztsov; V. A. Polyakov; V. I. Romanovsky; V. I. Rykalin; A. S. Sadovsky; V. D. Samoilenko; M. M. Shapkin; O. V. Stenyakin; O. G. Tchikilev; V. A. Uvarov; O. P. Yushchenko; B. Zh. Zalikhanov

doi:10.1140/epjc/s10052-021-08895-2

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2021) 81: 161
https://doi.org/10.1140/epjc/s10052-021-08895-2

Regular Article - Experimental Physics

Study of $K^{+} \to π^{0} e^{+} ν γ$ $K^+ \rightarrow \pi ^{0} e^{+} \nu \gamma$ decay with OKA setup

A. Yu. Polyarush¹^a, S. A. Akimenko², A. V. Artamonov², A. M. Blik², V. S. Burtovoy², V. N. Bychkov³, S. V. Donskov², V. A. Duk¹^,4, A. P. Filin², S. N. Filippov¹, A. M. Gorin², E. N. Gushchin¹, A. V. Inyakin², G. D. Kekelidze³, G. V. Khaustov², S. A. Kholodenko², A. A. Khudyakov¹, V. N. Kolosov², V. I. Kravtsov¹, Yu. G. Kudenko¹^,5^,6, V. F. Kurshetsov², V. A. Lishin², V. M. Lysan³, M. V. Medynsky², Yu. V. Mikhailov², V. F. Obraztsov², V. A. Polyakov², V. I. Romanovsky², V. I. Rykalin², A. S. Sadovsky², V. D. Samoilenko², M. M. Shapkin², O. V. Stenyakin², O. G. Tchikilev², V. A. Uvarov², O. P. Yushchenko² and B. Zh. Zalikhanov³

¹ Institute for Nuclear Research of the Russian Academy of Sciences, 117312, Moscow, Russia
² “NRC Kurchatov Institute-IHEP”, 142281, Protvino, Russia
³ Joint Institute of Nuclear Research, 141980, Dubna, Russia
⁴ INFN-Sezione di Perugia, Via A. Pascoli, 06123, Perugia, Italy
⁵ National Research Nuclear University (MEPhI), Moscow, Russia
⁶ Institute of Physics and Technology, Moscow, Russia

^a Polyarush@inr.ru

Received: 25 October 2020
Accepted: 19 January 2021
Published online: 16 February 2021

Abstract

Results of a study of the $K^{+} \to π^{0} e^{+} ν γ$ $K^+ \rightarrow \pi ^{0} e^{+} \nu \gamma$ 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 $K_{e 3}$ $K_{e3}$ decay are calculated for different cuts on $E_{γ}^{*}$ $E^*_\gamma$ and $c o s Θ_{e γ}^{*}$ $cos\Theta ^{*}_{e\gamma }$ . In particular, the branching ratio for $E_{γ}^{*} > 30$ $E^{*}_{\gamma }>30$ MeV and $Θ_{e γ}^{*} > 20^{\circ}$ $\Theta ^{*}_{e \gamma }>20^{\circ }$ is measured R = $\frac{B r (K^{+} \to π^{0} e^{+} ν_{e} γ)}{B r (K^{+} \to π^{0} e^{+} ν_{e})}$ $\frac{Br(K^+ \rightarrow \pi ^{0} e^{+} \nu _{e} \gamma ) }{Br(K^+ \rightarrow \pi ^{0} e^{+} \nu _{e})}$ = = (0.587±0.010(stat.)±0.015(syst.)) $\times 10^{- 2}$ $\times 10^{-2}$ , which is in a good agreement with ChPT $O (p^{4})$ $O(p^{4})$ calculations.

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