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* The program is subject to change.

* Breakfast : 8:00 ~ / Chamnari Hall, Hill condominium F, 3F

* Lunch & Dinner : 11:00~20:30(Last order 20:00) / Mountain Condominium, Mountain Cafeteria , Ski House 2F

Masahide Yamaguchi (IBS CTPU-CGA)

Title: New lower bounds on scattering amplitudes

Abstract: Under reasonable working assumptions including the polynomial boundedness, one proves the well-known Cerulus-Martin lower bound on how fast an elastic scattering amplitude can decrease in the hard-scattering regime. In this paper we consider two non-trivial extensions of the previous bound. (i) We generalize the assumption of polynomial boundedness by allowing amplitudes to exponentially grow for some complex momenta and prove a more general lower bound in the hard-scattering regime. (ii) We prove a new lower bound on elastic scattering amplitudes in the Regge regime, in both cases of polynomial and exponential boundedness. A bound on the Regge trajectory for negative momentum transfer squared is also derived. We discuss the relevance of our results for understanding gravitational scattering at the nonperturbative level and for constraining ultraviolet completions. In particular, we use the new bounds as probes of non-locality in black-hole formation, perturbative string theory, classicalization, Galileons, and infinite-derivative field theories, where both the polynomial boundedness and the Cerulus-Martin bound are violated.

Alex Pomarol (IFAE, Barcelona & KIAS)

Title: Bootstrapping large N QCD

Abstract: I will consider conformal to non-conformal transitions expected to occur in QCD with a large enough number of flavors. I will show the smoothness of physical quantities across this transition, determined by the logarithmic breaking of conformal invariance. I'll investigate this explicitly using holography. This analysis gives a possible explanation for the light scalar observed in QCD lattice simulations. These transitions can also implement new solutions to the hierarchy problem, having implications for cosmology.

Yang Yi(NYCU, Taiwan)

Title: Stringy Scaling of String Amplitudes in High Energy Limit

Abstract: Motivated by the linear relationship among n=4 string scattering amplitudes of open bosonic string theory in the high energy limit conjectured by Gross, we calculate ratios of the solvable infinite linear relations of arbitrary n-point hard string scattering amplitudes. For the n=5 case, we discover a new scaling behavior among hard string scattering amplitudes out of the scattering plane by a concrete calculation. We further show that this stringy scaling behavior is a general feature for arbitrary n-point hard string scattering amplitudes.

O-Kab Kwon(Sungkyunkwan University)

Title: Two point functions in two-dimensional inhomogeneous field theories

Abstract: In two dimensions, from a classical perspective, inhomogeneous field theory (IFT) exhibits a one-to-one correspondence with field theory on curved spacetime (FTCS). Utilizing this correspondence, we discuss quantum methodologies in the context of the IFT where Poincaré symmetry is broken explicitly. We explore the quantization of field theories for supersymmetry-preserving curvature backgrounds, discuss various approaches to computing two-point functions, and explore their physical significance.

Kimyeong Lee (KIAS)

Title: On 2d CFTs and Delign Series of Exceptional Lie Algebras

Abstract: We review the 2d conformal field theories related to the so-called Deligne series of exceptional Lie algebras and report our recent contributions to the subject.

Xiao-Gang He (Shanghai Jiao Tong University)

Title: Majorana Phase and Matter Effects in Neutrino Chial Oscillation

Abstract: Due to finite masses and mixing, for neutrinos propagation in space-time, there is a chiral os- cillation between left- and right- chiral neutrinos, besides the usual oscillation between different generations. The probability of chiral oscillation is suppressed by a factor of m2/E2 making the effect small for relativistic neutrinos. However, for non-relativistic neutrinos, this effects can be significant. In matter, the equation of motion is modified. When neutrinos produced in weak inter- action pass through the matter, the effective energies are split into two different ones depending on the helicity of the neutrino. This results in different oscillation behavior for neutrinos with different helicity, in particular there is a new resonant effect related to the helicity state of neutrino different than the usual MSW effect. For Majorana neutrinos, chiral oscillation also depends on Majorana phases.

Kihyeon Cho(KISTI)

Title: The status of Geant4 simulation tool kit

Abstract: Geant4 was created for precise simulation of high-energy physics experiments to explore the origin of the universe. It provides various physical models of electromagnetic interactions between particles and matter compared to statistical processing of other simulations. In addition, it is widely used not only in the field of high-energy physics but also in various fields such as cosmic radiation research, astrophysics, and medical physics due to its many types of roles and flexibility. Let me present the current status and future plan of Geant4 applications as well as its development.

Seungjoon Lee(Korea University)

Title: Forbidden Conformal Dark Matter at a GeV

Abstract: In this talk, I will present a new model of DM where the DM is a composite of a spontaneously broken conformal field theory. The DM is a thermal relic with its abundance determined by the freeze-out of annihilations to dilatons, the Goldstone boson of broken conformal symmetry. If the dilaton is heavier than the DM this is an example of forbidden DM. I will present a fully realistic model that describes this DM candidate and its interactions with ordinary particles with masses in the 0.1-10 GeV range. The conformal phase transition is supercooled and strongly first-order. It can source large stochastic gravitational wave signals consistent with those recently observed at pulsar timing arrays like NANOGrav. The majority of the viable parameter space will be probed by future detectors designed to search for long-lived particles, including most of the region favored by the NANOGrav signal. The rest of the parameter space can be probed at future direct detection experiments.

Fumiya Sano(IBS CTPU-CGA)

Title: Analytic Formulae for Inflationary Correlators with Dynamical Mass

Abstract: Massive fields can imprint unique oscillatory features on primordial correlation functions or inflationary correlators, which is dubbed the cosmological collider signal. In this work, we analytically investigate the effects of a time-dependent mass of a scalar field on inflationary correlators, extending previous numerical studies and implementing techniques developed in the cosmological bootstrap program. The time-dependent mass is in general induced by couplings to the slow-roll inflaton background, with particularly significant effects in the case of non-derivative couplings. By linearly approximating the time dependence, the mode function of the massive scalar is computed analytically, on which we derive analytic formulae for two-, three-, and four-point correlators with the tree-level exchange of the massive scalar. The obtained formulae are utilized to discuss the phenomenological impacts on the power spectrum and bispectrum, and it is found that the scaling behavior of the bispectrum in the squeezed configuration, i.e., the cosmological collider signal, is modified from a time-dependent Boltzmann suppression. By investigating the scaling behavior in detail, we are in principle able to determine the non-derivative couplings between the inflaton and the massive particle.

Qianhang Ding(IBS CTPU-CGA)

Title: Primordial black hole binaries as a probe of Hubble parameter

Abstract: Currently, the Hubble parameter is measured at early universe via CMB and late universe via standard candles. However, the result reports a Hubble tension, to reveal it, a measurement of Hubble parameter at intermediate redshift is important. In this talk, we will discuss the potential application of primordial black hole binaries as a probe of Hubble parameter at the intermediate redshift. In this application, we use the statistical properties of primordial black hole binaries to construct two methods to measure the Hubble parameter, which can also help us track the cosmic evolution.

Michiru Niibo(IBS-CTPU-CGA)

Title:Formation of defects associated with both spontaneous and explicit symmetry breaking.

Abstract: We are going to discuss the formation of topological defects. In the context of particle physics, such as neutrinos and axions, there are usually both spontaneous and explicit symmetry breaking. We consider how the explicit symmetry breaking term affects defect formation.

Hangil Choi(IBS-CTPU-CGA)

Title: Wave nature of gravitational wave lensing and its applications

Abstract: Gravitational lensing of gravitational wave(GW), or GW lensing for short, is a unique tool that enables us to explore the ultra-small-scale matter distribution in our universe. One of the distinctive features of GW lensing is its wave nature, which arises from the long wavelength of typical GW sources. Fully utilizing the wave nature, GW lensing can probe O(0.1) ~O(10) parsec scales matter distribution, depending on the type of GW source and detector. Investigating such small scales can provide crucial insight into the dark matter properties. In this presentation, I will provide a brief overview of the essence of GW lensing and discuss its applications to dark matter structures.

Hsiang-nan Li (Academia Sinica)

Title: Stringy Scaling of String Amplitudes in High Energy Limit

Abstract: Motivated by the linear relationship among n=4 string scattering amplitudes of open bosonic string theory in the high energy limit conjectured by Gross, we calculate ratios of the solvable infinite linear relations of arbitrary n-point hard string scattering amplitudes. For the n=5 case, we discover a new scaling behavior among hard string scattering amplitudes out of the scattering plane by a concrete calculation. We further show that this stringy scaling behavior is a general feature for arbitrary n-point hard string scattering amplitudes.

SungBo Sim(Chung-Ang University)

Title: SUSY SU(5) GUT and muon g-2 anomaly

Abstract: In the Minimal Supersymmetric extension of the Standard Model, we limit the parameter space to that which is compatible with the LHC and the muon g-2 experiment. Moreover, we examine the mechanism that gives us splitted sparticle mass spectrum and the impact of the resulting mini-split SUSY spectrum on gauge coupling unification and proton decay.

JunHo Song(Chung Ang University)

Title: Reheating and leptogenesis in the PQ pole inflation

Abstract: We propose the PQ higgs pole inflation model based on the conformal coupling between the Standard Model Higgs and gravity. The model can explain the origin of the axion by the angular part of a complex scalar, and it provides a possibility to explain the CMB experiments such as WMAP and Planck. In the reheating epoch, the inflaton can decay into other particles in the SM. We show that the right-handed neutrino(RHNs) can be produced by the inflaton decays and thermal bath, setting the initial condition for the RHN abundance during reheating, In the PQ Higgs pole inflation, we show the interplay between baryogenesis via leptogenesis, the successful inflation and the correct dark matter density from the axion.

MyeongJung Seong (Chung Ang University)

Title: PQ inflation and axion quality problem

Abstract: Axion had been introduced to solve the strong CP problem, and it also can be a nice candidate for dark matter. From the PQ field, we identify the radial component as the inflaton and the axial component as the QCD axion. In this case, we consider a slow-roll inflation in the presence of a PQ breaking higher order potential. During the slow-roll inflation, we show that the PQ breaking term induces a nonzero velocity for the axion, thus causing the kinetic misalignment for the axion. We discuss the implications of the successful inflation and the axion quality for determining the axion relic density.

Shu-Yu Ho(KIAS)

Title: Light Thermal Self-Interacting Dark Matter in the Shadow of Non-Standard Cosmology

Abstract: In this talk, we construct a viable model for a GeV scale self-interacting dark matter (DM), where the DM was thermally produced in the early universe. Here, a new vector-like fermion with a dark charge under the U(1)D gauge symmetry serves as a secluded WIMP DM and it can dominantly annihilate into the light dark gauge boson and singlet scalar through the dark gauge interaction. Also, the self-interaction of DM is induced by the light dark gauge boson via the same gauge interaction. In addition to these particles, we further introduce two Weyl fermions and a doublet scalar, by which the dark gauge boson produced from s-wave DM annihilations can mostly decay into active neutrinos after the dark symmetry breaking such that the CMB bound on the DM with low masses can be eluded. In order to have a common parameter region to explain the observed relic abundance and self-interaction of DM, we also study this model in a non-standard cosmological evolution, where the cosmic expansion driven by a new field species is faster than the standard radiation-dominated universe during the freezeout of DM. Reversely, one can also use the self-interacting nature of light thermal DM to examine the non-standard cosmological history of the universe.

Philip Lu(SNU)

Title: Regurgitated Dark Matter

Abstract: I will present a novel dark matter production scenario from evaporation of light primordial black holes (PBHs) in the early universe. In this model, the dark matter particles undergo a first order phase transition, forming compact remnants which collapse into PBHs. The subsequent regurgitation of these particles in the form of Hawking radiation decouples the interaction strength from their final abundance, in contrast to the thermal freeze-out mechanism. We show that this allows for WIMP-like dark matter with a Higgs portal interaction, even with parameters inaccessible to thermal freeze-out.

Jaehoon Jeong(KIAS)

Title: Hunting for Hypercharge Anapole Dark Matter

Abstract: We conduct a combined analysis to investigate dark matter (DM) with hypercharge anapole moments, focusing on scenarios where Majorana DM particles with spin 1/2 or 1 interact exclusively with Standard Model particles through U(1)Y hypercharge anapole terms. For completeness, we construct general, effective, and hypercharge gauge-invariant three-point vertices. These enable the generation of interaction vertices for both a virtual photon γ and

a virtual Z boson with two identical massive Majorana particles of any non-zero spin s, after the spontaneous breaking of electroweak gauge symmetry. For complementarity, we adopt an effective operator tailored to each dark matter spin allowing crossing symmetry. We calculate the relic abundance, analyze current constraints and future sensitivities from dark matter direct detection and collider experiments, and apply the conceptual naive perturbativity

bound. Our findings demonstrate that the scenario with spin-1 DM is more stringently constrained than that with spin-1/2, primarily due to the reduced annihilation cross-section and/or the enhanced rate of LHC mono-jet events. A significant portion of the remaining parameter space in the spin-1/2 DM scenario can be explored through upcoming Xenon experiments, with more than 20 ton-year exposure equivalent to approximately 5 years of running the XENONnT experiment. The spin-1 scenario can be almost entirely tested after the full run of the high-luminosity LHC, except for a very small parameter region where the DM mass is around 1 TeV. Our estimations, based on a generalized vertex, anticipate even stronger bounds and sensitivities for Majorana dark matter with higher spins.

YeolLin ChoeJo(KAIST)

Title: Dark Matter Induced Neutrino Mass Variation and the Second Leptogenesis

Abstract: In this work, we investigated the model in which the variation of the Majorana masses of neutrinos are caused by the coupling with the wave dark matter. Using this, we propose a novel scenario to explain the matter-antimatter asymmetry by twofold leptogenesis, which envisages two distinct phases of leptogenesis: one occurring above the electroweak scale and the other below it. The sphaleron process converts the first lepton asymmetry to baryon asymmetry, but not the second one due to its decoupling. This mechanism potentially explains the significant discrepancy between baryon and lepton asymmetries, as suggested by recent observations.

Jongkuk Kim(KIAS)

Title: Recent B+ → Kνν Excess, Muon (g − 2) and thermal WIMP DM in U(1)

Abstract: The Belle II collaboration recently announced that they observed the B+ → K+νν decay process for the first time. This dineutrino mode of B+ → K+νν has been theoretically identified as a very clean channel. However, their result encounters a 2.8σ deviation from the Standard Model (SM) calculation. On the other hand, last year, Fermilab released new data on muon (g − 2) away from the SM expectation with 5σ. In this talk, I will talk about the simplest UV-complete U(1)Lµ−Lτ -charged complex scalar Dark Matter (DM) model. Thanks to the existence of light dark Higgs boson and light dark photon, we can explain the observed relic density of DM and resolve the results reported by both Belle II and Fermilab experiments simultaneously without any modification of the thermal history of the Universe. As a byproduct, the Hubble tension is alleviated taking ∆Neff ≃ 0.3 induced by light Z′.

Adil Jueid(CTPU-IBS)

Title: The minimal left-right symmetric model at hadron colliders:

Abstract: In this talk, I will discuss the current status and future prospects of the searches of a right-handed charged gauge boson at the Large Hadron Collider (LHC). This particle is one of the natural predictions of the minimal left-right symmetric model (mLRSM) suggested initially to solve the problem of parity violation in weak interactions. First, I will discuss in depth the current bounds from the searches of right-handed gauge bosons and right-handed neutrinos in the final states of two leptons and two light untagged jets. Then I will discuss a new search strategy that we have proposed to find such a signal but employing top and bottom quarks instead of light jets. This talk is based on this recent work:

Fanrong Xu(Jinan University)

Title: B anomalies and SMEFT Interpretations

Abstract: The evolution of recent flavor anomalies, such as the faded RK in 2022 and the emergence of B to K nu nu in 2023, underscores the need for a renewed examination to unveil the presence of new physics. In this talk, I will firstly show new physics in terms of operator O9 still exists from global fits incorporating around 200 b -> s l l observables. Assuming that NP arises from a scale significantly above the EW scale and that the symmetry breaking in the SM is linearly realized, SMEFT provides an ideal working frame to accommodate data. Utilizing a set of only four SMEFT operators, the FCNC process b -> s nu nubar is correlated with b -> s l l, b -> c l nu, and more. We obtain Wilson coefficients of the four operators by a further global fit and more promising channels are predicted.

Adriana Menkara(Chung Ang University)

Title: The Supersymmetric Gegenbauer's Twin

Abstract: In this talk, we will see that for a spontaneously broken SO(N) global symmetry, there is an infinite class of radiatively stable pseudo-Nambu-Goldstone potentials: the Gegenbauer Polynomials. The “Gegenbauer Higgs” and “Gegenbauer’s Twin” scenarios are significantly less fine-tuned than their pNGB Higgs counterpart. These scenarios require relatively small values of the quotient (g*/yt)^2, suggesting that their UV completion may be a perturbative theory. A compelling candidate for such a UV-completion is the Supersymmetric Gegenbauer’s Twin presented in this work.

Xing-Yu Yang(KIAS)

Title: Observational phenomena on black hole with dark matter dress

Abstract: The accretion of dark matter around black holes could lead to the formation of surrounding halo, which can give characteristic observational phenomena. Such characteristic phenomena can be used to explore the nature of dark

matter. In this talk, I will talk about the observational phenomena on such dark matter dressed black holes, including the gravitational waves, the galactic gamma-ray background and the gravitational lensing.

Kihong Park(UST-KISTI)

Title: Study of Dark Photons Using Future Electron-Positron Colliders Based on Machine Learning

Abstract: A dark photon is a hypothetical particle that has a similar role to a photon in the Standard Model (SM) electromagnetic interaction but has been proposed as a force carrier with a potential link to dark matter. Detecting dark photon in particle collider experiments poses significant challenges owing to the interference from the SM events. This paper presents how effectively machine learning can reduce background events that pose a major problem in search for dark photons at future electron-positron accelerators/detectors: CEPC/CEPC, FCC-ee/IDEA and ILC/ILD. Based on the simplified model, we focus on the signal modes of e^+ e^-→A'A' and e^+ e^-→A' A' γ, where A' is a dark photon decaying into a muon pair. The dominant background originates from the SM. The background mode for the e^+ e^-→A'A' is e^+ e^-→μ^+ μ^- μ^+ μ^-, and for the e^+ e^-→A' A' γ, it is e^+ e^-→μ^+ μ^- μ^+ μ^- γ. The signal events are generated using MadGraph5 with the simplified model, while the background events are generated with the SM. We simulated detector responses using Delphes. Machine learning classification was performed using a Boosted Decision Trees classifier built on the Toolkit for Multivariate Data Analysis. Our study demonstrates a significant improvement in the signal-to-background ratio by an order of 100–10000 by effectively reducing background events using machine learning. Finally, we show the detector efficiencies from well-separated signal events.

Jong-Chul Park(Chungnam National University)

Title: Warm Surprises from Cold Duets

Abstract: We present surprising and comprehensive results on the cosmological implications of a model with two-component cold dark matter (CDM) beyond the single CDM paradigm. The annihilation of the heavier components to the lighter ones can significantly enhance the temperature of the latter, making them behave warm dark-matter-like even with conventional CDM-scale mass. For the first time, we investigate temperature evolution, density perturbation, power spectrum, and maximum circular velocity function via N-body simulation. We argue that such various cosmological properties provide important implications for ongoing and upcoming particle physics experiments in search for the elusive dark-matter candidates.

TaeHun Kim(KIAS)

Title: Emergent particles of a dS universe: Thermal interpretation of the stochastic formalism and beyond

Abstract: A thermal interpretation of the stochastic formalism of a slow-rolling scalar field in a de Sitter (dS) universe is given. By introducing a notion of emergent particles and a dual description of scalar fields, we show that the stochastic evolution of the infrared part of the field is equivalent to the Brownian motion in an abstract space filled with a heat bath of massless particles. The 1st slow-roll condition and the Hubble expansion are also reinterpreted in the abstract space as the speed of light and a transfer of conserved energy, respectively. Inspired by this, we sketch the quantum emergent particles, which may realize the Hubble expansion by an exponential particle production. This gives another meaning of dS entropy as entropy per Hubble volume in the global dS universe.

Dong Woo Kang(Jeonbuk National University)

Title: Cosmic Birefringence by Dark Photon

Abstract: We study the kinetic mixing between the cosmic microwave background (CMB) photon and the birefringent dark photon as a source of cosmic birefringence. We show that indeed the birefringence of the dark photon propagates to the CMB photon, but the resulting birefringence may not be uniform over the sky. Moreover, our investigation sheds light on the essential role played by kinetic mixing in the generation of two fundamental characteristics of the CMB: circular polarization and spectral distortion.

Carlo Branchina(Chung Ang University)

Title: UV-sensitivity in Kaluza Klein Theories: Naturalness and Dark Dimension

Abstract: When the Higgs potential or the vacuum energy are derived in the framework of higher dimensional effective field theories on a multiply connected spacetime with compact dimensions and non-trivial boundary conditions (as in the case of the Scherk-Schwarz SUSY breaking), the usual calculations lead to the conclusion that these quantities are naturally UV-insensitive. By means of a thorough analysis of the assumptions on which these calculations are based, I will show that this paradigm actually misses a crucial source of UV-sensitivity, ultimately connected to the non-trivial topology of the spacetime in these theories. As a consequence, the conclusions on the UV-insensitivity of the Higgs mass, of the Higgs potential, and on the existence of a Dark Dimension (that crucially depends on the supposed UV-insensitivity of the vacuum energy in Kaluza-Klein theories) need to be seriously reconsidered.

Rajibul Shaikh(SeoulTech)

Title: Rotating regularized Schwarzschild and JNW spacetimes as Kerr Black hole mimickers

Abstract: The Event Horizon Telescope has recently observed the images and shadows of the compact objects M87* and Sgr A* at the centres of the galaxies Messier 87 and Milky Way. This has opened up a new window in observational astronomy to probe and test gravity and fundamental physics in the strong-field regime. In this paper, we consider rotating versions of the regularised Schwarzschild and Janis-Newman-Winicour (JNW) metric, study their shadows, and constrain the metric parameters using the observed shadow sizes of M87* and Sgr A*. Depending on parameter values, the spacetimes represent either a regular black hole or a naked singularity or a wormhole. We find that, whereas the regular black hole case is always consistent with observations, the naked singularity case is not, as the latter casts a shadow which is much smaller than the observed ones. On the other hand, the shadow formed by the wormhole case is consistent with the observations for some parameter values. We put constraints on the wormhole throat radius by comparing its shadow with the observed ones of M87* and Sgr A*.

Koun Choi(IBS-CUP)

Title: Recent results from the Super-Kamiokande

abstract: The Super-Kamiokande (SK) is the world’s largest water Cherenkov detector tank which is sensitive to O(1)- O(100) GeV neutrinos. Aiming the first observation of diffuse supernova neutrino background (DSNB), the SK collaboration recently added Gadolinium to the water up to 0.03% Gd concentration,called SK-Gd. The addition of gadolinium improves sensitivity to the DSNB signal, thanks to the enhanced neutron tagging efficiency. Using the first data obtained in the SK-Gd, we set an upper limit on the electron antineutrino flux with energies of O(10) MeV, which can be interpreted as model-independent upper limit on DSNB flux. In this talk, I will present the status and prospects of DSNB analysis. I will also mention related studies, such as the study of the neutrino-oxygen neutral-current quasielastic (NCQE) cross section using atmospheric neutrinos and the first observation of the reactor neutrino flux.

Myeonghun Park(Seoultech)

Title: Exploring the Synergy of Kinematics and Dynamics for Collider Physics

Abstract: In collider experiments, an event is characterized by two distinct yet mutually complementary features: the ‘global features’ and the ‘local features’. Kinematic information such as the event topology of a hard process, masses, and spins of particles comprises global features spanning the entire phase space. This global feature can be inferred from reconstructed objects. In contrast, representations of particles in gauge groups, such as Quantum Chromodynamics (QCD), offer localized features revealing the dynamics of an underlying theory. These local features, particularly observed in the patterns of radiation as raw data in various detector components, complement the global kinematic features. In this talk, I will explain a simple but effective neural network architecture that seamlessly integrates information from both kinematics and QCD to enhance the signal sensitivity at colliders.

Kiwoon Choi(IBS)

Title: Probing BSM CP violation and the axion quality with electric dipole moments.

Abstract: In some models of physics beyond the Standard Model (BSM physics), one of the leading low energy consequences of the model appears in the form of the chromoelectric dipole moments (CEDMs) of the gluons and light quarks. We examine if these CEDMs can be distinguished from the QCD θ-term through the experimentally measurable nuclear and atomic electric dipole moments (EDMs) in both cases with and without a QCD axion. Our results suggest that EDMs can provide information not only on BSM CP violation, but also on the quality of the PQ symmetry characterizing the strength of UV-originated PQ breaking such as quantum gravity effects.

Wei-Chen Lin(Pusan National University)

Title: Euclidean wormholes and the origin of alpha-vacua

Absract: We investigate the cosmological observables from the Euclidean path integral approach. Especially, we study not the no-boundary compact instantons, but Euclidean wormholes, that can explain the creation of two universes from nothing. We considered perturbations and found a power spectrum formula. In the no-boundary case, the Euclidean vacuum uniquely points out the Bunch-Davies vacuum, while the Euclidean wormholes can allow a different de Sitter invariant vacuum, so-called the $alpha$-vacuum state. Therefore, from the point of view of the Euclidean path integral approach, the $alpha$-vacuum has a geometrical origin.

Hyun Min Lee(Chung-Ang University)

Title: Positivity bounds on Higgs-portal dark matter

Abstract: We consider the relic density and positivity bounds for freeze-out or freeze-in scalar dark matter with general Higgs-portal interactions up to dimension-8 operators. Dimension-4 and dimension-6 Higgs-portal interactions are proportional to mass squares for Higgs or scalar dark matter in certain microscopic models such as massive graviton, radion or general metric couplings with conformal and disformal modes. We discuss the implications of positivity bounds for microscopic models through dimension-8 derivative operators for Higgs and scalar dark matter. First, massive graviton or radion mediates attractive forces between Higgs and scalar dark matter and the resultant dimension-8 operators respect the positivity bounds. Second, the disformal couplings in the general metric allow for the subluminal propagation of graviton but violate the positivity bounds. We constrain the dimension-8 derivative Higgs-portal interactions by determining the relic density via freeze-out process or thermal scattering after reheating. The positivity bounds can also curb out the dimension-8 derivative Higgs-portal interactions nontrivially in the presence of the similar dimension-8 self-interactions for Higgs and dark matter.

Zhi Yong Wang(IHEP, CAS)

Title: The XYZ states at BESIII

Abstract: In this talk, several latest results about XYZ studies at BESIII will be presented. It contains 1) e+e- à gamma X(3872), omega X(3872), X(3872), the decay of X(3872)àpi0 chi_c2, pipi chi_c0, and a coupled channel analysis of the X(3872) line shape. In the line-shape of e+e- à gamma X(3872), we observed a potential structure around 4.2 GeV, whose parameters agree with Y(4230). The decay mode of e+e- à omega X(3872) is observed for the first time. We tried to search for the X(3872) signal in pi0 chi_c0 and pipi chi_c0 final states, but no obvious signal is found. A coupled channel analysis is performed with X(3872)àpipiJ/psi and D0D0pi0 to study its line-shape. 2) Y states with exclusive processes, e+e- à pipiJ/psi, pipi psi(3686), pipiX(3823), KKJ/psi, and phi/omega chi_c (hidden charm), and D*D*, Ds*Ds*, D0D*pi, and DDpipi (open charm). We observed many Y state candidates in above mentioned hidden charm final states, e.g. Y(4230), Y(4390), Y(4360), Y(4500), Y(4710), psi(4500), and so on. We also observed similar structures in the exclusive open charm final states. 3) Zcs(3985) àDs D*0, Ds*D0, KJ/psi. We observed the Zcs(3985) candidates in DsD0*+Ds*D0 mass spectrum, but haven’t found the obvious Zcs signal in KJ/psi mass spectrum.

Ying Li(YanTai University)

Title：Study of three-body B decays in PQCD

Abstract: Three-body B decays not only significantly broaden the study of B meson decay mechanisms but also provide information of resonant particles. Because of complicate dynamics, it is very hard for us to study the whole phase space in a specific approach. In this talk, we take B⟶KR⟶K+K− decays as examples and show the application of the perturbative QCD (PQCD) approach in studying the quasi-two-body B decays, where two particles move collinearly with large energy and the bachelor one recoils back. To describe the dynamics of two collinear particles, the S, P, and D-wave functions of kaon-pair with different waves are introduced. By keeping the transverse momenta, all possible diagrams including the hard spectator diagrams and annihilation ones can be calculated in PQCD approach. Most results are well consistent with the current measurements from BaBar, Belle, and LHCb experiments. Moreover, under the narrow-width approximation, we can extract the branching fractions of the two-body decays involving the resonant states and also predict the branching fractions of the corresponding quasi-two-body decays B⟶KR⟶π+π−. All predictions are expected to be tested in the ongoing LHCb and Belle-II experiments.

Jeonghun Moon(KISTI)

Title: Researches on implementing workflows for applied research(HEP) based big data-based API networks through research platforms.

Abstract: The data explosion in science and technology and the advancement of applied research are driving the need for large-scale networks and advanced linkages between analysis models for especially HEP. This paper analyzes the application cases of scientific research using ICT technology and introduces the application model of ICT technology for the transmission, storage, and processing of big data. In many fields dealing with science, it is evolving to utilize the results by linking analysis models through API networking of analysis SWs based on research platforms. We will analyze the deployment model of ICT technologies for such API networking.