The 16th Particle Physics Phenomenology Workshop

15 Jun 2026, 08:30 → 18 Jun 2026, 18:40 Asia/Taipei

NTHU

Martin Spinrath (NTHU)

Introduction

The Particle Physics Phenomenology (PPP) Workshop is a biennial meeting with a rich history dating back to 1992 (skipping only a few times due to incidents such as SARS and COVID), one of the most important gatherings in the particle physics community in Taiwan. The workshop serves as a vital platform for foreign and domestic scholars working on particle physics experiments and theories to share the latest experimental results and developments in various models or theoretical frameworks. It features comprehensive lectures on topics of current interest to the community, as well as shorter presentations on more specific applications. It aims to inspire innovative ideas and help form new collaborations among the participants.

Topics

On this 16th edition we will have lectures and talks on

• High Energy Astroparticle Physics
• Neutrino Physics
• Quantum Sensors
• Black Holes, Gravitational Waves & Particle Physics
• QCD & Nuclear Physics
• and more...

Coordinates

The 16th Particle Physics Phenomenology Workshop (PPP16) will be held at National Tsing Hua University (NTHU) from June 15 to 18, 2026. NTHU is located in Hsinchu, the silicon valley of Taiwan. The nearest international airport is Taoyuan International Airport (TPE).

We cordially welcome your participation and contributions!

Sponsors

We gratefully acknowledge financial support from NCTS (TG2.1 & TG2.4), the Department of Physics of NTHU and the Office of Research and Development, NTHU.

Monday 15 June

08:30 → 09:00 Welcome & Farewell

09:00 → 10:00 Invited Lecture: Neutrino Physics I

10:00 → 10:30 Coffee Break

10:30 → 12:00 Black Holes, Gravitational Waves & Particle Physics: Invited Talks: BHs, GWs & Particle Physics

10:30 The Maxwell-Einstein-Pauli Observatory: A Systematic Multimessenger Approach for Probing Fundamental Physics

The 21st century marks the beginning of the age of multimessenger astronomy. After decades of waiting the ground-based gravitational wave detectors of the Laser Interferometer Gravitational-Wave Observatory allowed us to directly detect gravitational waves, and the expanding network of neutrino detectors provided us with access to a broad range of previously undetected neutrino sources. Thus for the first time we have all four messengers, photons, gravitational waves, neutrinos, and cosmic rays, at our disposal to investigate the fundamental laws of physics. Unfortunately, the interpretation of the collected data still strongly relies on fitting them to the output of analytical and numerical models. However, if we want to extract all information transported by the different messenger signals, we have to develop a much more systematic approach for multimessenger observations and, in particular, the analysis of the collected data. The goal of this talk is now to present such an approach: The Maxwell-Einstein-Pauli Observatory. When realised the Maxwell-Einstein-Pauli Observatory will use data assimilation techniques to combine data with theoretical models, which has the potential to provide us with much more precise results than traditional fitting techniques. In my talk I will now first outline the basic structure of the Maxwell-Einstein-Pauli Observatory. Then I will provide a brief overview over different data assimilation techniques and how they help us to combine observational data with theoretical models. I will discuss potential science targets and how we can apply the method to probing gravity in the strong field regime in the close vicinity of black holes.

Speaker: Torben Christian Frost

11:15 Gravitational wave probes to new physics beyond the Standard Model

This talk will explore how gravitational-wave interferometers can serve as powerful probes of new physics across vastly different mass scales. I will first show that data from the LIGO-Virgo-KAGRA Collaboration can help resolve a long-standing puzzle: whether the GeV gamma-ray excess at the Galactic Center originates from annihilating weakly interacting massive particles or from a population of millisecond pulsars. Turning to lighter dark matter candidates, I will then demonstrate how the same gravitational-wave detectors enable the direct detection of ultralight bosons, including dark photons, axions, and dilatons. Together, these methods illustrate how gravitational wave experiments can be repurposed as powerful discovery tools for new physics.

Speaker: Yue Zhao

12:00 → 13:30 Lunch Break

13:30 → 14:30 Invited Lecture: Quantum Sensors I

14:30 → 15:15 Quantum Sensors: Invited Talks

15:15 → 15:45 Coffee Break

15:45 → 18:00 Other Aspects of Particle Physics: Invited Talks

15:45 Probing the Higgs Self-coupling via VBF Di-Higgs Production at a Multi-TeV Muon Collider

We investigate the sensitivity to the Higgs trilinear coupling (κ_λ) through di-Higgs production via vector-boson fusion (VBF) at a multi-TeV muon collider. A primary advantage of the muon collider environment is the significantly suppressed QCD background compared to hadron colliders, which provides a remarkably clean experimental signature for probing electroweak processes. We perform a detailed analysis using a dedicated simulation chain, examining the variations in both the production rate and kinematic distributions as a function of κ_λ. We employ advanced machine learning techniques to optimize signal-background separation and enhance the sensitivity to the Higgs potential. We estimate the expected precision on κ_λ. Our results highlight the unique potential of high-energy muon colliders for precision Higgs measurements in the VBF sector.

Speaker: Soojin Lee (National Tsing Hua University)

16:30 Freeze-in Production of Non-Abelian Millicharged Vector Dark Matter

We present the first predictive realization of vector freeze-in dark matter from a hidden non-Abelian gauge sector, spontaneously broken to a residual $U(1)$ with a massless dark photon mediator. A massive dark vector particle-antiparticle pair acquires small millicharges via a dimension-five kinetic mixing operator that induces a dimension-four mixing term with effective coefficient $\epsilon$, and interacts through the hidden gauge coupling $g_D$, linking it weakly to the Standard Model. Solving the relic abundance with a two-temperature Boltzmann evolution including plasmon decays, we find a wide region of parameter space that reproduces the observed density while satisfying astrophysical and cosmological bounds. This minimal framework links non-Abelian vector dynamics, long-range dark forces, and dark matter, and can be testable with upcoming sub-GeV dark matter direct-detection experiments.

Speaker: Dr Van Que Tran (NCTS, National Taiwan University)

Tuesday 16 June

09:00 → 10:00 Invited Lecture: High Energy Astroparticle Physics I

09:00 High-Energy Neutrinos — Basics

Do astrophysical sources produce TeV–PeV range neutrinos? Yes! I provide an introductory overview of neutrino production, neutrino propagation, and neutrino detection, then review key results.

Speaker: John Beacom (OSU)

10:00 → 10:30 Coffee Break

10:30 → 12:00 Other Aspects of Particle Physics: Invited Talks

10:30 New physics in toponium's shadow?

Recently, the CMS and ATLAS collaborations have reported a ttbar resonance excess near the ttbar threshold with above 5 sigma deviation from the SM pQCD prediction. This excess may be interpreted as a new pseudoscalar particle interacting with the top quark. Alternatively, it can be explained within the SM framework through toponium production—the bound state of a top quark pair, which can enhance the ttbar production cross section near the threshold. In this talk, I will discuss a combined scenario in which both a BSM particle and toponium production exist simultaneously, as would naturally occur if new physics couples to top quarks. In this case, not only does the pure BSM signal contribute to ttbar production, but the interference between the BSM particle and the SM also becomes very important. In particular, the interference can enhance or reduce the total cross section depending on the mass of the BSM particle. I will present how the interference modifies the total cross section and toponium line shape, and demonstrate its significant impact on constraining or reopening the BSM parameter space.

Speaker: Jinheung Kim (KIAS)

12:00 → 13:30 Lunch Break

13:30 → 14:30 Invited Lecture: Neutrino Physics II

14:30 → 15:15 Quantum Sensors: Invited Talks

15:15 → 15:45 Coffee Break

15:45 → 18:00 QCD & Nuclear Physics: Invited Talks

15:45 First-Principles Lattice Study of Dense QCD-like Theories

We present first-principles lattice studies of dense QCD-like theories, focusing on two-color QCD where the sign problem is absent. I will discuss results on the phase structure, the equation of state, and hadron spectroscopy at finite density.

Speaker: Etsuko Itou

Wednesday 17 June

09:00 → 10:00 Invited Lecture: High Energy Astroparticle Physics II

09:00 High-Energy Neutrinos — Frontiers

Can we drive progress in this field? Yes! I provide an overview of how to make better measurements, how we can use these to better understand astrophysics and particle physics, and how these opportunities fit in a broader framework of neutrino science.

Speaker: John Beacom (OSU)

10:00 → 10:30 Coffee Break

10:30 → 12:00 High Energy Astroparticle Physics: Invited Talks

10:30 The 20 GeV Fermi halo: evidence for dark matter annihilation?

Fifteen years of the Fermi Large Area Telescope (LAT) data in the halo region of the Milky Way (MW) are analyzed to search for gamma rays from dark matter annihilation. Gamma-ray maps within the region of interest (|l| < 60 deg, 10 deg < |b| < 60 deg) are modeled using known components plus a halo-like component. A statistically significant halo-like excess is found with a spectral peak around 20 GeV, and examination of the fit residual maps indicates that a spherically symmetric halo component fits the map data well. The radial profile agrees with annihilation by the smooth NFW density profile. Various systematic uncertainties are investigated, but the 20 GeV peak remains significant. The halo excess spectrum can be fitted by annihilation with a particle mass m ∼ 0.5-0.8 TeV and cross section <sigma v> ∼ (5-8) x10^{-25} cm3 s^-1 for the bb channel. This cross section is larger than the upper limits from dwarf galaxies and the canonical thermal relic value, but considering various uncertainties, especially the density profile of the MW halo, the dark matter interpretation of the 20 GeV “Fermi halo” remains feasible. The prospects for verification through future observations are briefly discussed.

Speaker: Tomonori Totani (Dept. Astronomy, Univ. of Tokyo)

11:15 Superheavy supersymmetric dark matter as the origin of the KM3NeT ultrahigh energy signal

We propose an explanation for the recently reported ultrahigh-energy neutrino signal at KM3NeT, which shows no clear association with known astrophysical sources. While decaying dark matter in the Galactic Center is a natural candidate, the observed arrival direction strongly suggests an extragalactic origin. We introduce a multicomponent dark matter scenario in which the components are part of a supermultiplet, with supersymmetry ensuring a nearly degenerate mass spectrum among the fields with different spins. In this setup, a cosmologically long-lived fermionic state decays into a slightly lighter bosonic dark matter state, producing a boosted neutrino spectrum with energy $E_\nu \sim 100$ PeV, determined by the mass difference. The heavy-to-light decay occurs at a cosmological redshift of $z \sim$ a few or higher, leading to an isotropic directional distribution of the signal.

Speaker: Yongsoo Jho

12:00 → 13:30 Discussion: Closed Meeting for Taiwan PIs

12:00 → 13:30 Lunch Break

13:30 → 15:00 Quantum Sensors: Invited Talks

14:15 Dark Matter Detection with Quantum Sensors

Recent years have seen active discussion of new approaches to detecting wave-like dark matter using quantum sensors. In this talk, I will present several proposals employing quantum sensors, such as superconducting qubits and Rydberg atoms, for dark matter detection. I will also discuss the potential of entangled states to enhance signal sensitivity and suppress noise.

Speaker: Takeo Moroi

15:00 → 15:30 Coffee Break

15:30 → 18:00 Contributed Talks: Parallel Session

Thursday 18 June

09:00 → 10:30 Neutrino Physics: Invited Talks

09:45 How Robust Is the $\delta_{CP}$ Measurement?

Measuring the leptonic CP phase $\delta_{CP}$ and resolving the
$\theta_{23}$ octant are primary objectives of DUNE and T2HK.
We show that two distinct effects can compromise the reliability of
these measurements. First, the poorly constrained $\nu_e$ and
$\bar{\nu}_e$ cross sections allow energy-dependent distortions that
partially mimic the $\delta_{CP}$-dependent spectral modulation,
reducing DUNE's CP-violation sensitivity by up to $\sim\!3\sigma$.
We demonstrate that the proposed $\nu$SCOPE facility at CERN can
recover this loss through percent-level measurements of
$\sigma_{\nu_\mu}$ and the $\sigma_{\nu_e}/\sigma_{\nu_\mu}$ ratio.
Second, complex non-standard interactions (NSI) in propagation ---
motivated by the current $\sim\!2\sigma$ NOvA--T2K tension --- induce
correlated biases in $\delta_{CP}$ and the $\theta_{23}$ octant when
DUNE data are interpreted under the standard three-flavor hypothesis.
Since T2HK is largely insensitive to these propagation effects, a
$\sim\!3\sigma$ discrepancy between the two experiments would
constitute a clear diagnostic of BSM physics. These results highlight
that both external cross-section constraints and baseline
complementarity are essential to ensure a robust and unbiased
determination of the oscillation parameters in the precision era.

Speaker: Joao Paulo Pinheiro (TDLI)

10:30 → 11:00 Coffee Break

11:00 → 12:00 Invited Lecture: Quantum Sensors II

12:00 → 13:30 Lunch Break

13:30 → 14:15 High Energy Astroparticle Physics: Invited Talks

14:15 → 15:45 Neutrino Physics: Invited Talks

14:15 POLARIS: A Sparse Radial Neutrino Telescope Design for the Pacific Ocean

We present POLARIS, a new sparse radial detector design for an underwater neutrino telescope. The design targets multi-PeV horizontal tracks with a minimal instrumentation density of around 1000 Digital Optical Modules. We evaluate the astronomy potential of this design through 5-sigma point source and diffuse flux detection limit, benchmarking against IceCube, KM3NeT ARCA, TRIDENT, NEON, TAMBO and RNO-G, spanning ice, water, and air-shower based detection techniques. Beyond their role in neutrino astronomy, neutrino telescopes have demonstrated remarkable ability to probe physics beyond the standard model, evolving into multi-purpose instruments competing with accelerator-based searches. POLARIS is an effective design to reach next-generation sensitivity at PeV energies either as a standalone instrument or as an extension of existing or planned underwater telescopes.

Speaker: Karolin Hymon

15:00 Impact of neutrino flavor conversions in core-collapse supernovae - dependence on location, time, and progenitor

Massive stars end their lives as giant explosions. What starts as a collapse of the stellar core is turned into an explosion driven by energy transfer of neutrinos. The neutrino densities become so high that coherent flavor conversions develop.
I give an overview of the explosion mechanism and the importance of neutrinos. I will present a set of 76 simulations in axial symmetry initialized with 13 different progenitor systems with an initial mass between 9 and 23 solar masses. Neutrino flavor conversions have the potential to enhance, hinder, enable, and prevent the shock revival. I will show what are the conditions that make flavor conversions beneficial or disadvantageous for a successful explosion. Finally, I will highlight how the gravitational wave signal of a galactic core-collapse supernova could be used to constrain beyond standard model physics.

Speaker: Jakob EHRING (Academia Sinica, Institute of Physics)

15:45 → 16:15 Coffee Break

16:15 → 17:00 Other Aspects of Particle Physics: Invited Talks

17:00 → 17:40 Discussion: Future of Particle Physics Phenomenology in Taiwan and the World

17:40 → 18:00 Welcome & Farewell