arXiv subjects

Zhuojun Hu

Publications and source records attributed to Zhuojun Hu.

4 recordsLinked to original sources

arXiv2026

Development of an early warning method incorporating pre-supernova neutrino light curves

Massive stars ($M>8\mathrm{M_\odot}$) emit neutrinos known as pre-supernova (pre-SN) neutrinos through thermal and nuclear interactions for cooling the stellar core during the final stage of stellar evolution. Real-time monitoring of their pre-SN neutrino interaction rate offers a crucial opportunity to issue an early warning to a core-collapse supernova. Some neutrino detectors, including KamLAND and Super-Kamiokande already operate pre-SN alarm systems based on a statistically significant excess of the observed event rate over the expected background. To improve alarm sensitivity, an alarm method which incorporates the time evolution of the observed pre-SN neutrino event rate was proposed in A. Sheshukov et al. (2021). We evaluate the performance of the light-curve likelihood approach under realistic KamLAND and SK operating conditions, including realistic background rates, global false-alarm-rate calibration, and the combined alarm. The results demonstrate a significant improvement in the alarm time and distance compared to the conventional rate-only method, while maintaining the same false alarm rate.

astro-ph.HE↗

arXiv2021

Light dark bosons in the JUNO-TAO neutrino detector

This work presents a sensitivity study of a reactor liquid scintillator detector to three kinds of dark bosons with masses below 1 MeV, such as dark photons, axion-like particles and light scalar bosons. The JUNO-TAO detector with Taishan nuclear reactor is taken as a reference. With proposed 180 days data taking, the sensitivity to the dark bosons can reach $\sim10^{-5}$ 95%C.L. for the optimized signal to background ratio for the electron coupling constant $\it{g_X} $ through inverse Compton-like scattering. Similar calculations are completed for axion-like particles and scalar bosons. The background systematic uncertainty presents as the main limiting factor for the further sensitivity improvement. Several remarks are made to the controversial analysis for the NEOS experiment. Additionally the differential and the inverse differential cross sections have been derived for all three boson types and their interactions with electrons in liquid scintillator.

hep-ex↗

arXiv2020

Global oscillation data analysis on the $3ν$ mixing without unitarity

We present results of a combined analysis in neutrino oscillations without unitarity assumption in the $3ν$ mixing picture. Constraints on neutrino mixing matrix elements are based on recent data from the reactor, solar and long-baseline accelerator neutrino oscillation experiments. The current data are consistent with the standard $3ν$ scheme. The precision on different matrix elements can be as good as a few percent at $3σ$ CL, and is mainly limited by the experimental statistical uncertainty. The $ν_e$ related elements are the most precisely measured among all sectors with the uncertainties $<20\%$. The measured leptonic CP violation is very close to the one assuming the standard $3ν$ mixing. The deviations on normalization and the unitarity triangle closure are confined within $\mathcal{O}(10^{-3})$, $\mathcal{O}(10^{-2})$ and $\mathcal{O}(10^{-1})$, for $ν_e$, $ν_μ$ and $ν_τ$ sectors, respectively. We look forward to the next-generation neutrino oscillation experiments \textit{such as} DUNE, T2HK, and JUNO, especially the precise measurements on $ν_τ$ oscillations, to significantly improve the precision of unitarity test on the $3ν$ mixing matrix.

hep-ph↗

arXiv2018

The possibility of leptonic CP-violation measurement with JUNO

The existence of CP-violation in the leptonic sector is one of the most important issues for modern science. Neutrino physics is a key to the solution of this problem. JUNO (under construction) is the near future of neutrino physics. However CP-violation is not a priority for the current scientific program. We estimate the capability of $δ_{\rm CP}$ measurement, assuming a combination of the JUNO detector and a superconductive cyclotron as the antineutrino source. This method of measuring CP-violation is an alternative to conventional beam experiments. A significance level of 3$σ$ can be reached for 22% of the $δ_{\rm CP}$ range. The accuracy of measurement lies between 8$^{\rm o}$ and 22$^{\rm o}$. It is shown that the dominant influence on the result is the uncertainty in the mixing angle $Θ_{23}$.

hep-ph↗