I will present an overview of the experimental neutrino physics programs in Taiwan: past, present and future. The development also reflects how the subject evolve.
Probing the inverted mass ordering region and venturing into the normal mass ordering region of neutrinos is a crucial goal for the next generation of neutrinoless double beta decay (0νββ) experiments. The absence of definitive signatures, the quest for heightened sensitivity, background minimization, statistical significance, and exploration of multiple isotopes collectively drive the move...
Scenario with a lepton-flavor-violating (LFV) boson, either a scalar or a vector exchange, is an intriguing physics phenomenon beyond Standard Model. This LFV boson coupling in the presence of muons leads to a rich phenomenology including an extra contribution to muon anomalous magnetic moment desirable for alleviating the discrepancy between the SM prediction and the newest combined (Fermilab...
The recent ATOMKI experiments provided evidence pointing towards the existence of an X17 boson in the anomalous nuclear transitions of Beryllium-8, Helium-4, and Carbon-12. The favored ranges for the couplings between the X17 boson and the first-generation quarks, denoted as $\epsilon_u$ and $\epsilon_d$, are determined through fittings to the above nuclear transitions.
In this work, we...
New physics beyond the Standard Model (BSM) with an extra neutral boson can be constrained from the observation of SN1987A, since the production of this neutral boson in a supernova (SN) could accelerate the SN cooling and potentially lead to a period of the neutrino burst incompatible with the observation.% for certain ranges of model parameters. The constraint to the model is formulated by...
Probing Axion-like Particles: Novel Detection Channels and Expanding Experimental Sensitivity for Dark Matter and Solar ALPs
Axions and axionlike particles (ALPs) represent a promising avenue in the quest for new physics, potentially shedding light on the profound mysteries enveloping our Universe, including the nature of dark matter and dark energy. ALPs are well-motivated dark...
Based predominantly on arXiv: 2012.07519 (JCAP 03 (2021) 084) and also on arXiv: 2207.07142 (JCAP 10 (2022) 018).
We have updated the constraints on flavour universal (and also flavour specific) neutrino self-interactions mediated by a heavy scalar, in the effective 4-fermion interaction limit. We use the relaxation time approximation to modify the collisional neutrino Boltzmann equations,...
The proton is a spin-1/2 fundamental particle, discovered as a basic constituent of atomic nuclei by Rutherford in 1917. It and its isospin partner, neutron, carry the majority of visible mass in our universe. Starting from Gell-Mann's quark model, the substructures of protons have been explored mostly by the deep-inelastic scattering and Drell-Yan process for more than five decades. In this...
The TMD soft function may be obtained by formulating the Wilson line in terms of auxiliary 1-dimensional fermion fields on the lattice. We take inspiration from heavy quark effective theory (HQET) in order to define the auxiliary field. Our computation takes place in the region of the lattice that corresponds to the “spacelike” region in Minkowski space in order to obtain the Collins soft...
We discuss the origin of neutrino masses confirmed by various oscillation experiments. Especially, we consider the case when the Standard Model is extended by right-handed neutrinos and describe the so-called seesaw mechanism. We also discuss the possible tests of the seesaw mechanism
where all neutrinos are Majorana fermions and the lepton number is violated. In particular, we show how...
In this talk we will discuss the phenomenology of neutrino mass models where leptoquarks mediate the generation of Dirac mass terms. The presence of leptoquarks that couple to all generations of quarks and leptons can have interesting consequences for meson decays. In particular the RD,RD*anomalies can be addressed, as well as the recent observation by Belle-II of an excess in the B-> K + inv...
We consider the positivity bounds for scalar dark matter with effective Higgs-portal couplings up to dimension-8 operators. Taking the superposed states for Standard Model Higgs and scalar dark matter, we show that the part of the parameter space for the effective couplings, otherwise unconstrained by phenomenological bounds, is ruled out by the positivity bounds on the dimension-8 derivative...
Recent measurement of muon anomalous magnetic dipole moment (muon $g-2$), performed by the Muon $g-2$ Collaboration at Fermilab, differs from the Standard Model (SM) value calculated by the Muon $g-2$ Theory Initiative Group at the combined statistical significance of $5.1\sigma$. Taking at face value, such discrepancy could be an indication of some sort of new physics. In this paper, we...
We perform dispersive analyses of representative physical observables
(heavy quark decay widths, neutral meson mixing, etc.) and demonstrate
that the parameters involved in scalar interactions of the Standard
Model (SM) is not completely free. The mass hierarchy from the neutrino
masses up to the electroweak scale, and the distinct quark and lepton
mixing patterns may be accommodated...
We analyze the variation of the chiral phase transition temperature as a function of the baryon number and strangeness chemical potentials by calculating the leading order curvature coefficients in the light and strange quark flavor basis as well as in the conserved charge ($B, S$) basis. Making use of scaling properties of the magnetic equation of state (MEoS) and including diagonal as well...
I will take an overview of dark matter models and their potential connections with the world of flavours. This includes dark matter models where dark matters couples to specific Standard Model particles but also models where new dark flavours are proposed.
The study of first order phase transitions (FOPT) in the early Universe provides a window into fundamental physics. One possible observational signature can come in the form of low frequency stochastic gravitational waves, which may explain the NANOGrav observation. FOPT dynamics may be realized in certain BSM scenarios, which can also accommodate particle species in the dark sector. In this...
We study axion-like particles (ALPs) with quark-flavor-violating couplings at the LHC.
Specifically, we focus on the theoretical scenario with ALP-top-up and ALP-top-charm interactions, in addition to the more common quark-flavor-diagonal couplings.
The ALPs can thus originate from decays of top quarks which are pair produced in large numbers at the LHC, and then decay to jets.
If these...
Motivated by a hint of possible excess of a new resonance decaying to eμ at 146 GeV, we try to interpret the excess in the context of the type-III two-Higgs-doublet-model. We find that the excess is only moderately constrained by low-energy lepton-flavor-violation processes, in particular the μ→eγ decay. We also compare the CMS bounds across the entire search region against constraints of μ→eγ...
When a core-collapse supernova fails to explode or barely exploded, i.e., unable to unbind most of the stellar envelope, the associated proto-neutron star is expected to eventually implode into a black hole. In this scenario, the neutrino luminosity spectrum will then see an abrupt end as a result of the engulfment of the luminous core and the increasing gravitational redshift. The dynamics...
