arXiv subjects

O. Alterkait

Publications and source records attributed to O. Alterkait.

21 records · Page 2Linked to original sources

arXiv2024

Measurement of ambient radon progeny decay rates and energy spectra in liquid argon using the MicroBooNE detector

We report measurements of radon progeny in liquid argon within the MicroBooNE time projection chamber (LArTPC). The presence of specific radon daughters in MicroBooNE's 85 metric tons of active liquid argon bulk is probed with newly developed charge-based low-energy reconstruction tools and analysis techniques to detect correlated $^{214}$Bi-$^{214}$Po radioactive decays. Special datasets taken during periods of active radon doping enable new demonstrations of the calorimetric capabilities of single-phase neutrino LArTPCs for $β$ and $α$ particles with electron-equivalent energies ranging from 0.1 to 3.0 MeV. By applying $^{214}$Bi-$^{214}$Po detection algorithms to data recorded over a 46-day period, no statistically significant presence of radioactive $^{214}$Bi is detected, and a limit on the activity is placed at $<0.35$ mBq/kg at the 95% confidence level. This bulk $^{214}$Bi radiopurity limit -- the first ever reported for a liquid argon detector incorporating liquid-phase purification -- is then further discussed in relation to the targeted upper limit of 1 mBq/kg on bulk $^{222}$Rn activity for the DUNE neutrino detector.

hep-ex↗

arXiv2024

Search for heavy neutral leptons in electron-positron and neutral-pion final states with the MicroBooNE detector

We present the first search for heavy neutral leptons (HNL) decaying into $νe^+e^-$ or $νπ^0$ final states in a liquid-argon time projection chamber using data collected with the MicroBooNE detector. The data were recorded synchronously with the NuMI neutrino beam from Fermilab's Main Injector corresponding to a total exposure of $7.01 \times 10^{20}$ protons on target. We set upper limits at the $90\%$ confidence level on the mixing parameter $\lvert U_{μ4}\rvert^2$ in the mass ranges $10\le m_{\rm HNL}\le 150$ MeV for the $νe^+e^-$ channel and $150\le m_{\rm HNL}\le 245$ MeV for the $νπ^0$ channel, assuming $\lvert U_{e 4}\rvert^2 = \lvert U_{τ4}\rvert^2 = 0$. These limits represent the most stringent constraints in the mass range $35<m_{\rm HNL}<175$ MeV and the first constraints from a direct search for $νπ^0$ decays.

hep-ex↗

arXiv2023

First demonstration of $\mathcal{O}(1\,\text{ns})$ timing resolution in the MicroBooNE liquid argon time projection chamber

MicroBooNE is a neutrino experiment located in the Booster Neutrino Beamline (BNB) at Fermilab, which collected data from 2015 to 2021. MicroBooNE's liquid argon time projection chamber (LArTPC) is accompanied by a photon detection system consisting of 32 photomultiplier tubes used to measure the argon scintillation light and determine the timing of neutrino interactions. Analysis techniques combining light signals and reconstructed tracks are applied to achieve a neutrino interaction time resolution of $\mathcal{O}(1\,\text{ns})$. The result obtained allows MicroBooNE to access the ns neutrino pulse structure of the BNB for the first time. The timing resolution achieved will enable significant enhancement of cosmic background rejection for all neutrino analyses. Furthermore, the ns timing resolution opens new avenues to search for long-lived-particles such as heavy neutral leptons in MicroBooNE, as well as in future large LArTPC experiments, namely the SBN program and DUNE.

hep-ex↗