arXiv subjects

Guo-yuan Huang

Publications and source records attributed to Guo-yuan Huang.

32 records · Page 2Linked to original sources

arXiv2020

RGE-induced $μ$-$τ$ symmetry breaking: an analysis of the latest T2K results

The T2K collaboration has recently reported their results, which gives the best-fit values of the atmospheric mixing angle $\sin^2 θ_{23} = 0.53$ and the Dirac CP-violating phase $δ= -1.89$ for normal neutrino mass ordering. We give a possible theoretical origin of such values based on the $μ$-$τ$ reflection symmetry. It has been found that the breaking of such symmetry using one-loop renormalization-group equations (RGEs) in the framework of minimal supersymmetric standard model can fit well with the latest T2K results and the recent global fits. To make a quantitative analysis, we have included for the first time the complete dataset of oscillation, beta decay, neutrinoless double-beta decay and cosmological observations in comparing the theory to experiments. We also further examine the importance of such breaking patterns for neutrinoless double-beta decay experiments.

hep-ph↗

arXiv2020

Hunting the Glashow Resonance with PeV Neutrino Telescopes

The Glashow resonant scattering, $i.e$. ${\overlineν^{}_{e} + e^{-} \rightarrow W^{-} \rightarrow \text{anything}}$, offers us a possibility of disentangling $\overlineν^{}_{e}$ from the total astrophysical neutrino fluxes. Meanwhile, a great number of high-energy neutrino telescopes, with various detection mechanisms, are advancing towards a better understanding of one of the most energetic frontiers of the Universe. In this work, we investigate a connection between through-going muons at IceCube and the Glashow resonance signal through the channel $W^{-} \rightarrow μ$. We find that for IceCube, muons from $\overlineν^{}_{e}$ can induce a $\sim20\%$ excess of PeV events around the horizontal direction. However, the current statistic of IceCube is not enough to observe such an excess. We also address the novel possibility of $\overlineν^{}_{e}$ detection via $W^{-} \rightarrow τ$ at telescopes aiming to detect Earth-skimming and mountain-penetrating neutrinos. The subsequent hadronic decay of a tau will induce an extensive air shower which can be detected by telescopes with Cherenkov or fluorescence techniques. Similar to IceCube, it is challenging to observe the Glashow resonance excess from the Earth-skimming neutrinos. Nevertheless, we find it is promising to observe Glashow resonance events with a mountain as the target.

hep-ph↗

arXiv2020

Effective neutrino masses in KATRIN and future tritium beta-decay experiments

Past and current direct neutrino mass experiments set limits on the so-called effective neutrino mass, which is an incoherent sum of neutrino masses and lepton mixing matrix elements. The electron energy spectrum which neglects the relativistic and nuclear recoil effects is often assumed. Alternative definitions of effective masses exist, and an exact relativistic spectrum is calculable. We quantitatively compare the validity of those different approximations as function of energy resolution and exposure in view of tritium beta decays in the KATRIN, Project 8 and PTOLEMY experiments. Furthermore, adopting the Bayesian approach, we present the posterior distributions of the effective neutrino mass by including current experimental information from neutrino oscillations, beta decay, neutrinoless double-beta decay and cosmological observations. Both linear and logarithmic priors for the smallest neutrino mass are assumed.

hep-ph↗

arXiv2019

Towards the meV limit of the effective neutrino mass in neutrinoless double-beta decays

In this paper, we emphasize why it is important for future neutrinoless double-beta ($0νββ$) decay experiments to reach the sensitivity to the effective neutrino mass $|m^{}_{ββ}| \approx 1~{\rm meV}$. Assuming such a sensitivity and the precisions on neutrino oscillation parameters after the JUNO experiment, we fully explore the constrained regions of the lightest neutrino mass $m^{}_1$ and two Majorana-type CP-violating phases $\{ρ, σ\}$. The implications for the neutrino mass spectrum, the effective neutrino mass $m^{}_β$ in beta decays and the sum of three neutrino masses $Σ\equiv m^{}_1 + m^{}_2 + m^{}_3$ relevant for cosmological observations are also discussed.

hep-ph↗

arXiv2019

Probing Cosmic Axions through Resonant Emission and Absorption in Atomic Systems with Superradiance

The $μ$eV-mass axion is one of the most promising candidates for cold dark matter, and remains to be a well-motivated solution to the CP problem of Quantum Chromodynamics (QCD) via the Peccei-Quinn mechanism. In this paper, we propose a novel method to detect the dark-matter axions in our galaxy via the resonant emission $|{\rm e}\rangle \to |{\rm g}\rangle + γ+ γ^{\prime}_{} + a$ (or absorption $a + |{\rm e}\rangle \to |{\rm g}\rangle + γ+ γ^{\prime}_{}$) in an atomic system with superradiance, where $|{\rm e}\rangle$ and $|{\rm g}\rangle$ stand for the excited and ground energy levels of atoms, respectively. A similar process via $|{\rm e}\rangle \to |{\rm g}\rangle + γ+ a$ (or $a + |{\rm e}\rangle \to |{\rm g}\rangle + γ$) is also put forward to probe the axion-electron coupling. For the nominal experimental setup assuming a background-free environment, most of the parameter space for typical QCD axion models can be covered with parahydrogen molecules or ytterbium atoms. However, the background in a realistic experimental setup remains to be a major issue that needs to be solved in future studies. Searching for better atomic or molecular candidates may be required for a bigger signal-to-noise ratio.

hep-ph↗

arXiv2019

Testing unitarity of the $3\times 3$ neutrino mixing matrix in an atomic system

Unitarity of the $3\times 3$ lepton flavor mixing matrix $V$ is unavoidably violated in a seesaw mechanism if its new heavy degrees of freedom are slightly mixed with the active neutrino flavors. We propose to use the atomic transition process ${\left| \rm e \right> \to\left|\rm g \right> + γ+ ν^{}_{i} + \overlineν^{}_{j}}$ (for $i, j = 1, 2, 3$), where $\left|\rm e \right>$ and $\left|\rm g \right>$ stand respectively for the excited and ground levels of an atomic system, to probe or constrain the unitarity-violating effects of $V$. We find that the photon spectrum of this transition will be distorted by the effects of $V V^\dagger \neq {\bf 1}$ and $V^\dagger V \neq {\bf 1}$ as compared with the $V V^\dagger = V^\dagger V = {\bf 1}$ case. We locate certain frequencies in the photon spectrum to minimize the degeneracy of effects of the unitarity violation and uncertainties of the flavor mixing parameters themselves. The requirements of a nominal experimental setup to test the unitarity of $V$ are briefly discussed.

hep-ph↗

arXiv2019

Constraining Neutrino Lifetimes and Magnetic Moments via Solar Neutrinos in the Large Xenon Detectors

The multi-ton-scale liquid xenon detectors, with an excellent energy resolution of a few keV, will be constructed to probe the dark-matter particles. In this paper, we show that precision measurements of the low-energy solar neutrinos via the elastic neutrino-electron scattering in this kind of detectors are able to improve the present limits on neutrino lifetimes and neutrino magnetic moments by about one order of magnitude. We carefully study the impact of the unknown neutrino mass spectrum on the ultimate limits in the case of non-radiative visible neutrino decays. In the case of invisible neutrino decays, the lower bounds $τ^{}_1/m^{}_1 \gtrsim 3 \times 10^{-2}~{\rm s}/{\rm eV}$ and $τ^{}_2/m^{}_2 \gtrsim 8\times 10^{-3}~{\rm s}/{\rm eV}$ at the $2σ$ level can be obtained for a total exposure of $70~{\rm ton}\cdot {\rm year}$. Furthermore, a restrictive constraint on the effective magnetic moment of neutrinos $μ^{}_{\rm eff} \lesssim 2.6\times 10^{-12}~μ^{}_{\rm B}$, with $μ^{}_{\rm B}$ being the Bohr magneton, can be achieved. This is among the best results that will be available in the laboratory experiments in the near future.

hep-ph↗

arXiv2019

Impact of an eV-mass sterile neutrino on the neutrinoless double-beta decays: a Bayesian analysis

To quantitatively assess the impact of an eV-mass sterile neutrino on the neutrinoless double-beta ($0νββ$) decays, we calculate the posterior probability distribution of the relevant effective neutrino mass $|m^\prime_{ee}|$ in the (3+1)$ν$ mixing scenario, following the Bayesian statistical approach. The latest global-fit analysis of neutrino oscillation data, the cosmological bound on the sum of three active neutrino masses from {\it Planck}, and the constraints from current $0νββ$ decay experiments are taken into account in our calculations. Based on the resultant posterior distributions, we find that the average value of the effective neutrino mass is shifted from $\overline{|m^{}_{ee}|} = 3.37\times 10^{-3}~{\rm eV}$ (or $7.71\times 10^{-3}~{\rm eV}$) in the standard 3$ν$ mixing scenario to $\overline{|m^{\prime}_{ee}|}=2.54\times 10^{-2}~{\rm eV}$ (or $2.56\times 10^{-2}~{\rm eV}$) in the (3+1)$ν$ mixing scenario, with the logarithmically uniform prior on the lightest neutrino mass (or on the sum of three active neutrino masses). Therefore, a null signal from the future $0νββ$ decay experiment with a sensitivity to $|m^{}_{ee}| \approx \mathcal{O}(10^{-2}_{})~{\rm eV}$ will be able to set a very stringent constraint on the sterile neutrino mass and the active-sterile mixing angle.

hep-ph↗

arXiv2018

Correlation of normal neutrino mass ordering with upper octant of $θ^{}_{23}$ and third quadrant of $δ$ via RGE-induced $μ$-$τ$ symmetry breaking

The recent global analysis of three-flavor neutrino oscillation data indicates that the {\it normal} neutrino mass ordering is favored over the inverted one at the $3σ$ level, and the best-fit values of the largest neutrino mixing angle $θ^{}_{23}$ and the Dirac CP-violating phase $δ$ are located in the higher octant and the third quadrant, respectively. We show that all these important issues can be naturally explained by the $μ$-$τ$ reflection symmetry breaking of massive neutrinos from a superhigh energy scale down to the electroweak scale due to the one-loop renormalization-group equations (RGEs) in the minimal supersymmetric standard model (MSSM). The complete parameter space is explored {\it for the first time} in both Majorana and Dirac cases, by allowing the smallest neutrino mass $m^{}_1$ and the MSSM parameter $\tanβ$ to vary in their reasonable regions.

hep-ph↗

arXiv2018

Neutrinophilic Axion-Like Dark Matter

The axion-like particles (ALPs) are very good candidates of the cosmological dark matter, which can exist in many extensions of the standard model (SM). The mass range of the ALPs as the dark matter can extend from a sub-eV scale to almost $10^{-22}~{\rm eV}$. On the other hand, the neutrinos are found to be massive and the SM must be extended to explain the sub-eV neutrino masses. It becomes very interesting to consider an exclusive coupling between these two low scale frontiers that are both beyond the SM. The propagation of neutrinos inside the Milky Way would undergo the coherent forward scattering effect with the ALP background, and the neutrino oscillation behavior can be modified by the ALP-induced potential. Assuming a derivative coupling between the ALP and the three generations of active neutrinos, possible impacts on the neutrino oscillation experiments have been explored in this paper. In particular, we have numerically studied the sensitivity of the Deep Underground Neutrino Experiment (DUNE). The astrophysical consequences of such coupling have also been investigated systematically.

hep-ph↗

arXiv2018

Matter effects on the flavor conversions of solar neutrinos and high-energy astrophysical neutrinos

Can we observe the solar eclipses in the neutrino light? In principle, this is possible by identifying the lunar matter effects on the flavor conversions of solar neutrinos when they traverse the Moon before reaching the detectors at the Earth. Unfortunately, we show that the lunar matter effects on the survival probability of solar $^8{\rm B}$ neutrinos are suppressed by an additional factor of $1.2\%$, compared to the day-night asymmetry. However, we point out that the matter effects on the flavor conversions of high-energy astrophysical neutrinos, when they propagate through the Sun, can be significant. Though the flavor composition of high-energy neutrinos can be remarkably modified, it is quite challenging to observe such effects even in the next-generation of neutrino telescopes.

hep-ph↗

arXiv2018

Sterile neutrinos as a possible explanation for the upward air shower events at ANITA

The ANITA experiment has observed two unusual upgoing air shower events which are consistent with the $τ$-lepton decay origin. However, these events are in contradiction with the standard neutrino-matter interaction models as well as the $\rm EeV$ diffuse neutrino flux limits set by the IceCube and the cosmic ray facilities like AUGER. In this paper, we have reinvestigated the possibility of using sterile neutrino hypothesis to explain the ANITA anomalous events. The diffuse flux of the sterile neutrinos is less constrained by the IceCube and AUGER experiments due to the small active-sterile mixing suppression. The quantum decoherence effect should be included for describing the neutrino flux propagating in the Earth matter, because the interactions between neutrinos and the Earth matter are very strong at the EeV scale. After several experimental approximations, we show that the ANITA anomaly itself is able to be explained by the sterile neutrino origin, but we also predict that the IceCube observatory should have more events than ANITA. It makes the sterile neutrino origin very unlikely to account for both of them simultaneously. A more solid conclusion can be drawn by the dedicated ANITA signal simulations.

hep-ph↗

arXiv2018

Observational Constraints on Secret Neutrino Interactions from Big Bang Nucleosynthesis

We investigate possible interactions between neutrinos and massive scalar bosons via $g^{}_ϕ \overlineν νϕ$ (or massive vector bosons via $g^{}_V \overlineν γ^μνV^{}_μ$) and explore the allowed parameter space of the coupling constant $g^{}_ϕ$ (or $g^{}_V$) and the scalar (or vector) boson mass $m^{}_ϕ$ (or $m^{}_V$) by requiring that these secret neutrino interactions (SNIs) should not spoil the success of Big Bang nucleosynthesis (BBN). Incorporating the SNIs into the evolution of the early Universe in the BBN era, we numerically solve the Boltzmann equations and compare the predictions for the abundances of light elements with observations. It turns out that the constraint on $g^{}_ϕ$ and $m^{}_ϕ$ in the scalar-boson case is rather weak, due to a small number of degrees of freedom. However, in the vector-boson case, the most stringent bound on the coupling $g^{}_V \lesssim 6\times 10^{-10}$ at $95~\%$ confidence level is obtained for $m^{}_V \simeq 1~{\rm MeV}$, while the bound becomes much weaker $g^{}_V \lesssim 8\times 10^{-6}$ for smaller masses $m^{}_V \lesssim 10^{-4}~{\rm MeV}$. Moreover, we discuss in some detail how the SNIs affect the cosmological evolution and the abundances of the lightest elements.

hep-ph↗

arXiv2016

Discriminating between Thermal and Nonthermal Cosmic Relic Neutrinos through Annual Modulation at PTOLEMY

If massive neutrinos are Dirac particles, the proposed PTOLEMY experiment will hopefully be able to discover cosmic neutrino background via $ν^{}_e + {^3}{\rm H} \to {^3}{\rm He} + e^-$ with a capture rate of $Γ^{}_{\rm D} \approx 4~{\rm yr}^{-1}$. Recently, it has been pointed out that right-handed components of Dirac neutrinos could also be copiously produced in the early Universe and become an extra thermal or nonthermal ingredient of cosmic relic neutrinos, enhancing the capture rate to $Γ^{}_{\rm D} \approx 5.1~{\rm yr}^{-1}$ or $Γ^{}_{\rm D} \approx 6.1~{\rm yr}^{-1}$. In this work, we investigate the possibility to distinguish between thermal and nonthermal spectra of cosmic relic neutrinos by measuring the annual modulation of the capture rate. For neutrino masses of $0.1~{\rm eV}$, we have found the amplitude of annual modulation in the standard case is ${\cal M} \approx 0.05\%$, which will be increased to $0.1\%$ and $0.15\%$ in the presence of additional thermal and nonthermal right-handed neutrinos, respectively. The future detection of such a modulation will be helpful in understanding the Majorana or Dirac nature of massive neutrinos.

hep-ph↗