TAUN 2024, The 8th TAUN collaboration meeting

Monday 25 Nov 2024, 09:20 → 18:00 Asia/Seoul

B438 (IBS, Theory Building)

The 8th TAUN collaboration meeting

The TAUN collaboration meeting is a casual meeting among five IBS physics centers (CTPU-CGA, CTPU-PTC, CAPP, CUP and CENS) in Daejeon. The main goal is to understand what other groups are doing in common research areas and to develop collaborationship between theory-experiment and/or different experimental groups. We encourage those who have an interest in those subjects and want to communicate with particle physicists to participate in the event.

TAUN represents the four physics research centers:

Center for Theoretical Physics of the Universe, Cosmology, Gravity and Astroparticle physics group
Center for Theoretical Physics of the Universe, Particle Theory and Cosmology group
Center for Axion and Precision Physics Research
Center for Underground Physics
Center for Exotic Nuclear Studies.

Date: 2024 November 25, 09:30~17:00

Place: IBS Theory Building, B438

Organizers :
Sanghyeon Chang (CTPU-PTC, IBS)
Eunju Jeon (CUP, IBS)
Dong-Won Jung (CTPU-CGA, IBS)
Youngman Kim (CENS,IBS)
Sung Woo Youn (CAPP, IBS)

09:20 Opening remark

CTPU-CGA

Convener: Dr Dong-Won Jung (IBS CTPU-CGA)

1 General algorithm for embedding 4D geometries in 5D braneworld models

We develop a general algorithm that enables the consistent embedding of any four-dimensional static and spherically symmetric geometry into any five-dimensional single-brane braneworld model, characterized by an injective and nonsingular warp factor. Furthermore, we supplement the algorithm by introducing a method that allows one to, in principle, reconstruct 5D field theories that support the aforementioned geometries.

Speaker: Dr Theodoros Nakas (CTPU-CGA)

2 Understanding ghosts in scalar-tensor theories of gravity

Pushing beyond the boundaries of general relativity has long been a major goal in both theoretical and experimental physics, especially in the pursuit of a quantum theory of gravity and the explanation of cosmological phenomena like dark energy and cosmic acceleration. Constructing modified gravity models often leads to additional degrees of freedom, but these can also introduce problematic, non-physical elements, such as "ghosts" and Ostrogradsky instabilities. Such instabilities render the theory unviable by causing unboundedness in the Hamiltonian, leading to the breakdown of predictability.
In this work, we investigate the nature and origin of ghost instabilities within scalar-tensor theories of gravity. We begin with simple toy models, which serve as a controlled environment for understanding the mechanisms by which ghost degrees of freedom emerge. These models help illustrate how adding higher-order derivative terms or modifying the kinetic structure can lead to the appearance of ghosts, even when the theory initially seems stable. The final aim is to progressively go to R+f(G) Gauss-Bonnet gravity and see why, in opposition with f(R) models, there are ghosts in these theories.

Speaker: Mr Joffrey Le Grix (CTPU-CGA)

10:30 Break

CENS

Convener: Dr Yunghee Kim (CENS)

3 Precision Frontier from Nuclear Decay

Nuclear decay has been utilized for decades to study weak interaction and structure of
nuclei. In particular, it has served as a probe of New Physics through a high-precision
measurement for the coefficient of - angular correlation, Fierz interference term, and
asymmetry. Combining the precision frontier with the high-energy one from LHC constrains the coupling of exotic weak current at per-mil level, which is equivalent to a hypothetical TeV-mass particle search. The unitarity test of Cabibbo-Kobayashi-Maskawa (CKM) matrix is another exemplar of the crossroad of two frontiers. Here we have focused on the extraction of |V ud |, which can be obtained directly from the -decay properties of nuclei. A recent experiment at the INFN Legnaro National Laboratory aiming to measure the branching ratio of 10 C superallowed decay will be presented.

Speaker: Dr Jeongsu Ha (CENS)

4 Wavefunction Matching in Nuclear Lattice EFT

Ab initio calculations play a crucial role in understanding nuclear properties. One of the primary challenges is performing accurate calculations for systems with complex interactions that are difficult for the chosen computational method to handle. In this talk, the wavefunction matching approach will be introduced as a method to address these challenges in nuclear physics. Additionally, a brief overview of nuclear lattice EFT will be provided.

Speaker: Dr Myungkuk Kim (CENS)

11:50 Lunch

CTPU-PTC

Convener: Dr Sanghyeon Chang (CTPU-PTC)

5 CosmiXs: Cosmic messenger spectra for indirect dark matter searches

The spectra of stable particles such as photons, positrons,
antiprotons and neutrinos are one of the main ingredients to calculate
the fluxes of cosmic rays and radiation searched for in indirect
detection experiments. The modeling of the whole process is however
very complicated since after dark matter annihilation or decay, a
number of phenomena occur: including resonance decays, parton
showering, hadronization and hadron decays. Therefore the modeling
itself cannot be performed from first principles. I will discuss some
progress in this direction and present CosmiXs which uses VINCIA to
properly model electroweak corrections, and handles the polarization
information. I will then move to the modeling of antideuterons and
discuss briefly the associated theoretical uncertainties (The dataset
can be found in this repo: https://github.com/ajueid/CosmiXs)
Talk is based on:
https://arxiv.org/abs/2411.04815
https://arxiv.org/abs/2312.01153
https://arxiv.org/abs/2303.11363
https://arxiv.org/abs/2202.11546

Speaker: Dr Adil Jueid (CTPU-PTC)

6 Machine Learning for Galactic Dynamics: Neural Stellar Density Estimation for Mapping Dark Matter in the Local Universe

Recent advances in machine learning (ML), particularly neural density
estimation like normalizing flows, diffusion models, and flow
matching, have opened new doors for high-precision, model-independent
density estimation.
These techniques are highly valuable for galactic dynamics studies, as
they allow us to estimate the distribution of stars in phase space
(position and velocity) without relying on traditional simplified
models.
By combining these ML-based stellar density estimates and equation of
motion solvers for inferring gravitational fields, we can measure the
local dark matter density in a model-independent way.
This talk presents new research opportunities along this direction,
focusing on modeling objects in our local universe using neural
networks and using them for understanding local galactic dark matter
distribution.
We anticipate that these modern machine learning-based approaches will
allow us to fully utilize the potential of current and future
astronomical catalogs, significantly improving our understanding of
dark matter in the local universe.

Speaker: Dr Sung Hak Lim (CTPU-PTC)

14:00 Break

CUP

Convener: Dr Hyun Su Lee (CUP)

7 General Purpose Large Liquid Scintillator Detector at Yemilab

Speaker: Dr Jaison Lee (CUP)

8 Recent advances and future of COSINE-100

Speaker: Dr Gyunho Yu (CUP)

15:20 Break

CAPP

Convener: Dr Sung Woo Youn

9 Revisiting Chiral Magnetic Effects and Axions

Speaker: Prof. Deogki Hong

10 But what is axion haloscope?

Speaker: Dr Saebyeok Ahn

11 Accelerating Axion Haloscope Experiments: Strategies and Innovations at CAP

Speaker: Dr Danho Ahn

2024_November_TAUN_DanhoAhn_v2.pdf

16:50 Closing remark