arXiv subjects

I. S. Tiurin

Publications and source records attributed to I. S. Tiurin.

4 recordsLinked to original sources

arXiv2026

A search for the dark photon in the OKA experiment

A search for the massless dark photon in the decay $K^{+}\to π^{+}π^{0}\overline{{} γ}$ is performed with the OKA detector exposed to 17.7 GeV/c RF separated secondary beam of the U70 Proton Synchrotron. A high-statistics data sample of the $K^{+}$ decays is used for a missing mass search of the stable massless invisible dark photon ($\overlineγ$) in the final state. In the absence of a statistically valuable signal the upper limit on the branching ratio of the decay $Br<2.0\times10^{-6}$ is obtained with a 90% confidence level based on a realistic matrix element of the process. Currently, it is the best upper limit for this hypothetical decay channel.

hep-ex↗

arXiv2024

The upper limit on the $K^+ \to π^0π^0π^0e^+ν$ decay

A search for the $K^{+} \to π^{0}π^{0}π^{0}e^+ν$ decay is performed by the OKA collaboration. The search is based on $3.65 \times 10^9 ~ K^+$ decays. No signal is observed. The upper limit set is $BR(K^{+} \to π^{0}π^{0}π^{0}e^+ν) < 5.4\times 10^{-8} ~ 90\%$ CL, 65 times lower than the one currently listed by PDG.

hep-ex↗

arXiv2024

Searches for the light invisible axion-like particle in $K^{+}\toπ^{+}π^{0}a$ decay

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 $K^{+} \to π^{+} π^{0} a$. No signal is observed, the upper limits for the branching ratio of the decay are calculated. The $90\%$ confidence level upper limit is changing from $2.5\cdot10^{-6}$ to $2\cdot10^{-7}$ for the ALP mass from 0 to 200 MeV/$c^{2}$, except for the region of $π^{0}$ mass, where the upper limit is $4.4\cdot10^{-6}$.

hep-ex↗

arXiv2023

Observation of $K^{+} \to π^{+}π^{0}π^{0}γ$ decay

The $K^{+} \to π^{+}π^{0}π^{0}γ$ decay is observed by the OKA collaboration. The branching ratio is measured to be $(4.1 \pm 0.9(stat) \pm 0.4(syst))\times 10^{-6}$. The branching ratio and $γ$ energy spectrum are consistent with ChPT prediction.

hep-ex↗