arXiv subjects

P. T. Quyen

Publications and source records attributed to P. T. Quyen.

8 recordsLinked to original sources

arXiv2026

Atmospheric Mass-Squared Splitting at Sub-Percent Precision as a $CPT$ Symmetry Probe

In this paper, we present an improved test of $CPT$ symmetry in the neutrino sector by analyzing the atmospheric mass-squared splittings, $Δm^2_{31}$ and $Δ\overline{m}^2_{31}$, using on-going JUNO and future DUNE and Hyper-Kamiokande experiments. Our study focuses on the discrepancy $δ_{ν\overlineν}(Δm^2_{31}) = Δm^2_{31} - Δ\overline{m}^2_{31}$, achieving unprecedented precision by exploiting the high statistics and reduced systematic uncertainties of these facilities. The combined analysis yields a sensitivity to $CPT$ violation at the level of $2\times 10^{-5}~\text{eV}^2$ at $3σ$ confidence level, representing a $60\%$ improvement over the joint T2K-NO$ν$A-JUNO analysis. These results highlight the crucial role of multi-experiment synergies in testing fundamental symmetries of nature.

hep-ph↗

arXiv2025

Disentangling data contributions to the precision measurement of the largest leptonic mixing angle

This study examines the precise measurement of the largest leptonic mixing angle $θ_{23}$ through the analysis of neutrino oscillation data samples. Our findings indicate that, contrary to common understanding, the $ν_μ(\barν_μ)\rightarrow ν_{e}(\barν_{e})$ appearance samples, rather than the $ν_μ(\barν_μ)\rightarrow ν_μ(\barν_μ)$ disappearance samples, are sensitive to test the hypothesis of maximal mixing $θ_{23}=π/4$, particularly if $θ_{23}$ resides in the higher octant and $\sin^2θ_{23}<0.54$. The former serves as the primary source for determining the octant of the $θ_{23}$ mixing angle; however, the latter remains relevant if $θ_{23}$ is indeed in the lower octant with $\sin^2θ_{23}<0.42$. In a joint T2HK and DUNE analysis, utilizing only appearance sub-samples can exclude the maximal-mixing and determine the actual octant for about 60\% of the currently allowed range of the $θ_{23}$ angle. We argue that, despite the presence of parameter degeneracy, the precise measurement of $θ_{23}$ exhibits minimal dependence on other unknown factors, including the CP-violation phase and neutrino mass ordering.

hep-ph↗

arXiv2024

On Precision of the Leptonic Mixing Angle $θ_{23}$ and its Implications for the Flavor Models

Among three leptonic mixing angles, $θ_{23}$ angle, which characterizes the fractional contribution of two flavor eigenstates $ν_μ$ and $ν_τ$ to the third mass eigenstate $ν_3$, is known to be the largest but the least precisely measured. The work investigates possible reach of $θ_{23}$ precision with two upcoming gigantic accelerator-based long-baseline neutrino experiments, namely Hyper-Kamiokande and DUNE experiments as well as a possible joint analyses of future neutrino facilities. Our simulation yields that each experiment will definitely establish the octant of $θ_{23}$ angle for all values within 1$σ$ parameter interval, while considering the current limitation. However, if the actual value is $0.48\leq \sin^2θ_{23}\leq 0.54$, it becomes challenging for these two experiments to reject the maximal ($θ_{23}=π/4$) hypothesis and conclude its octant. This octant-blind region can be further explored with the proposed facilities ESSnuSB and a neutrino factory. Accurate determination of the mixing angle $θ_{23}$, as well as the accuracy of $δ_{CP}$, is crucial for examining a certain category of discrete non-Abelian leptonic flavor models. Specifically if CP is conserved in leptonic sector, the combined analysis of Hyper-K and DUNE will rule out the majority of these models. However, if the CP is maximally violated, higher precision of $δ_{CP}$ is necessary for testing these flavor models.

hep-ph↗

arXiv2022

Stringent constraint on CPT violation with the synergy of T2K-II, NO$ν$A extension, and JUNO

Neutrino oscillation experiments have measured precisely the mass-squared differences of three neutrino mass eigenstates, and three leptonic mixing angles by utilizing both neutrino and anti-neutrino oscillations. The possible CPT violation may manifest itself in the difference of neutrino and anti-neutrino oscillation parameters, making these experiments promising tools for testing CPT invariance. We investigate empirically the sensitivity of the CPT test via the difference in mass-squared splittings ($Δm^2_{31} - Δ\overline{m}^2_{31}$) and in leptonic mixing angles ($\sin^2θ_{23} - \sin^2\overlineθ_{23}$) with the synergy of T2K-II, NO$ν$A extension, and JUNO experiments. If the CPT symmetry is found to be conserved, the joint analysis of the three experiments will be able to establish limits of $|Δm^2_{31} - Δ\overline{m}^2_{31}|$ < $5.3\times 10^{-3} \text{eV}^2$ and $|\sin^2θ_{23} - \sin^2\overlineθ_{23}|$ < $0.10$ at 3$σ$ C. L. on the possible CPT violation. We find that with ($Δm^2_{31} - Δ\overline{m}^2_{31}$), the dependence of the statistical significance on the relevant parameters to exclude the CPT conservation is marginal, and that, if the difference in the best-fit values of $Δm^2_{31}$ and $Δ\overline{m}^2_{31}$ measured by MINOS(+) and NO$ν$A persists as the true, the combined analysis will rule out the CPT conservation at 4$σ$ C. L.. With the ($\sin^2θ_{23} - \sin^2\overlineθ_{23}$), the statistical significance to exclude CPT invariance depends strongly on the true value of $θ_{23}(\overlineθ_{23})$. In case of maximal mixing of $θ_{23}$, the CPT conservation will be excluded at 3$σ$ C. L. or more if the difference in the best-fit values of $θ_{23}$ and $\overlineθ_{23}$ remains as the true.

hep-ph↗

arXiv2022

Practical use of reactor anti-neutrinos for nuclear safeguard in Vietnam

One of the most abundant man-made sources of low energy (few~MeVs) neutrinos, reactor neutrino, is not only useful for studying neutrino properties, but it is also used in practical applications. In this study, we investigate the practical use of reactor neutrino detectors for nuclear safeguard in Vietnam, specifically at the Dalat Nuclear Reactor, a future research facility, and presumably commercial reactors with 500~kW, 10~MW, and 1000~MW thermal powers, respectively. We compute the rate of observed inverted beta decay events, as well as the statistical significance of extracting isotope composition under the practical assumptions of detector mass, detection efficiency, and background level. We find that a 1-ton detector mass can allow us to detect the reactor's on-off transition state from a few hours to a few days, depending on the standoff distance and reactor thermal power. We investigate how background and energy resolution affect the precision of the extracted weapon-usable ${}^{239}\text{Pu}$ isotope. We conclude that in order to distinguish the 10\% variation of the ${}^{239}\text{Pu}$ in the 10~MW thermal power reactor, a 1-ton detector placed 50~m away must achieve 1\% background level. Increasing the statistics by using a 10x larger detector or placing it $\sqrt{10}$ times closer to the reactor alleviates the requirement of the background level to 10\%.

hep-ex↗

arXiv2021

Neutrino mass spectrum: Present indication and future prospect

The fact that neutrinos are massive has been the most crucial evidence of physics beyond the Standard Model of elementary particles. To date, we still do not know how neutrinos get mass and why their mass is much smaller than that of their charged fermion cousins. The precise determination of the neutrino mass spectrum has become one of the central tasks of neutrino physics, providing critical input for understanding the nature of neutrino mass and extending our model. The present landscape of the neutrino mass spectrum is reviewed and explored in this article using data from the neutrino oscillation, cosmology, and beta decay. In addition, we discuss the possibility of relevant programs elucidating the neutrino mass spectrum in the coming decades.

hep-ph↗

arXiv2021

Physics potentials with a combined sensitivity of T2K-II, NO$ν$A extension and JUNO

Leptonic \textit{CP} violation search, neutrino mass hierarchy determination, and the precision measurement of oscillation parameters for a unitary test of the leptonic mixing matrix are among the major targets of the ongoing and future neutrino oscillation experiments. The work explores the physics reach for these targets by around 2027, when the third generation of the neutrino experiments starts operation, with a combined sensitivity of three experiments: T2K-II, NO$ν$A extension, and JUNO. It is shown that a joint analysis of these three experiments can conclusively determine the neutrino mass hierarchy. Also, at certain values of \emph{true} \dcp, it provides closely around a $5σ$ confidence level (C.L.) to exclude \textit{CP}-conserving values and more than a $50\%$ fractional region of \emph{true} $δ_{\text{CP}}$ values can be explored with a statistic significance of at least a $3σ$ C.L. Besides, the joint analysis can provide unprecedented precision measurements of the atmospheric neutrino oscillation parameters and a great offer to solve the $θ_{23}$ octant degeneracy in the case of nonmaximal mixing.

hep-ph↗

arXiv2021

Multi-pixel Photon Counter for operating the tabletop cosmic-ray detector under loosely controlled conditions

Multi-Pixel Photon Counter (MPPC) has been recently emerged and realized as a great type of Silicon Photomultiplier to replace or compensate for the conventional vacuum-based Photomultiplier tubes. MPPC provides many striking features such as high electrical gain, outstanding photon detection efficiency, fast timing response, immunity to the magnetic field, low-voltage operation, compactness, portability, and cost-effectiveness. The report introduces and examines the electrical and optical characteristics of the MPPC under loosely controlled environmental conditions. Also, we report a measurement of the light yield captured by the MPPC when the cosmic ray passes through the plastic scintillator, demonstrating that such setup is suitable to build a simple, cost-effective tabletop cosmic-ray detector for educational and research purposes.

physics.ins-det↗