arXiv subjects

Tse-Chun Wang

Publications and source records attributed to Tse-Chun Wang.

7 recordsLinked to original sources

arXiv2022

Taking Neutrino Pictures via Electrons

In this paper we discuss the prospects to take a picture of an extended neutrino source, i.e., resolving its angular neutrino luminosity distribution. This is challenging since neutrino directions cannot be directly measured but only estimated from the directions of charged particles they interact with in the detector material. This leads to an intrinsic blurring effect. We first discuss the problem in general terms and then apply our insights to solar neutrinos scattering elastically with electrons. Despite the aforementioned blurring we show how with high statistics and precision the original neutrino distributions could be reconstructed.

hep-ph↗

arXiv2020

Flavour Symmetry Embedded -- GLoBES (FaSE-GLoBES)

Neutrino models based on flavour symmetries provide the natural way to explain the origin of tiny neutrino masses. At the dawn of precision measurements of neutrino mixing parameters, neutrino mass models can be constrained and examined by on-going and up-coming neutrino experiments. We present a supplemental tool Flavour Symmetry Embedded (FaSE) for General Long Baseline Experiment Simulator (GLoBES), and it is available via the link https://github.com/tcwphy/FASE_GLoBES. It can translate the neutrino mass model parameters to standard neutrino oscillation parameters and offer prior functions in a user-friendly way. We demonstrate the robustness of FaSE-GLoBE with four examples on how the model parameters can be constrained and even whether the model is excluded by an experiment or not. We wish that this toolkit will facilitate the study of new neutrino mass models in an effecient and effective manner.

hep-ph↗

arXiv2019

Precision measurements on $δ_\text{CP}$ in MOMENT

As it is very promising to expect a discovery of CP violation in the leptonic sector, the precision measurement of the Dirac CP phase $δ_\text{CP}$ is going to be one of the key interests in the future neutrino oscillation experiments. In this work, we examine the physics reach of the proposed medium baseline muon decay experiment MOMENT. In order to identify potential bottlenecks and opportunities to improve CP precision in MOMENT, we investigate the effect of statistical error, systematic uncertainties, fraction of the muon beam polarity, and adjusting the baseline length to match the first or second oscillation maximum on the precision measurement of $δ_\text{CP}$. We also simulate superbeam experiments T2K, NO$ν$A, T2HK, DUNE and T2HKK in comparison and complementary to MOMENT. To reach the precision of $δ_\text{CP}$ at 12$^\circ$ or better at 1$σ$ confidence level, we find it sufficient to combine the data of MOMENT, DUNE and T2HK.

hep-ph↗

arXiv2019

Non-standard interactions versus planet-scale neutrino oscillations

The low-energy threshold and the large detector size of Precision IceCube Next Generation Upgrade (PINGU) can make the study on neutrino oscillations with a planet-scale baseline possible. In this task, we consider the configuration that neutrinos are produced at CERN and detected in the PINGU detector, as a benchmark. We discuss its sensitivity of measuring the size of non-standard interactions (NSIs) in matter, which can be described by the parameter $ε_{αβ}$ ($α$ and $β$ are flavors of neutrinos). We find that the CERN-PINGU configuration improves $\tildeε_{μμ}\equivε_{μμ}-ε_{ττ}$ and $ε_{μτ}$ significantly compared to the next-generation accelerator neutrino experiments. Most of degeneracy problems in the precision measurements can be resolved, except the one for $\tildeε_{μμ}\sim-0.035$. Moreover, we point out that this configuration can also be used to detect the CP violation brought by NSIs. Finally, we compare the physics potential in this configuration to that for DUNE, T2HK and P2O, and find that the CERN-PINGU configuration can significantly improve the sensitivity to NSIs.

hep-ph↗

arXiv2019

Confronting Tri-direct CP-symmetry models to neutrino oscillation experiments

Tri-direct CP symmetry is an economical neutrino model building paradigm, and it allows to describe neutrino masses, mixing angles and CP violation phases in terms of four free parameters. Viability of a class of tri-direct CP models is examined with a comprehensive simulation of current and future neutrino oscillation experiments. Two benchmark models as well as the full parameter space are carefully scanned, and the parameter degeneracy problem is observed from the constraint of one group of neutrino oscillation experiments. Complementary roles from the accelerator neutrino experiments (e.g., T2HK and DUNE) and reactor neutrino experiments (e.g., JUNO) are crucial to break the degeneracy and nail down fundamental neutrino mixing parameters of the underlying theory.

hep-ph↗

arXiv2011

Schwinger mechanism in dS_2 and AdS_2 revisited

Recalculating the Bogoliubov coefficients from the solutions in Phys. Rev. D 78, 103517 (2008), we obtain the mean number of boson pairs in a uniform electric field in the global coordinates dS_2 and AdS_2, which have the correct zero-field and zero-curvature limits, and study the vacuum persistence at one-loop. The mean number in AdS_2 gives the lowest limit to the Breitenloher-Freedman bound in the uniform electric field, and the mean numbers in dS_2 and AdS_2 satisfy the reciprocal relation N_{dS} (R, E) N_{AdS} (R, E) = 1 under the analytical continuation of the scalar curvature R.

hep-th↗

arXiv2011

The Early-Time Evolution of the Cosmological Perturbations in f(R) Gravity

We investigate the evolution of the linear cosmological perturbations in f(R) gravity, an alternative to dark energy for explaining the late-time cosmic acceleration. We numerically calculate the early-time evolution with an approximation we contrive to solve a problem that commonly appears when one solves the full evolution equations. With the approximate evolution equations we can fairly assess the effect of the gravity modification on the early-time evolution, thereby examining the validity of the general-relativity (GR) approximation that is widely used for the early universe. In particular, we compare the CMB photon density perturbation and the matter density perturbation obtained respectively by our approximation and the conventional GR approximation. We find that the effect of the gravity modification at early times in f(R) gravity may not be negligible. We conclude that to be self-consistent, in the f(R) theory one should employ the approximation presented in this paper instead of that of GR in the treatment of the early-time evolution.

astro-ph.CO↗