Workshop on particle physics and cosmology 2021

26 Nov 2021, 09:00 → 28 Nov 2021, 14:00 Asia/Seoul

3F OPUS (Jeju Hidden Cliff (제주 히든 클리프 호텔))

Seong Chan Park (Yonsei University)

Workshop on Particle Physics and Cosmology 2021 (Nov 26-28, 2021) hosted by APCTP, KIAS, Yonsei

Welcome to the “Workshop on Particle Physics and Cosmology 2021”, to take place on Nov 26-28, 2021 in Jeju. All talks will be face-to-face after a long break due to Pandemic. The workshop will bring together researchers working in the fields of theoretical particle physics and cosmology to discuss the latest results and to exchange ideas. Those who wishes to present his/her talk should apply to Indico page (under progress) till the end of October.

Topics to be discussed include:

• Collider

• Flavor

• Dark Matter

• Neutrinos

• Cosmology

• Multi-messengers (cosmic rays, gravitational waves,...)

• BSM theory/formal/lattice/others

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<Announcement>

Hotel check-out is done individually at the Lobby (3F) before 11:00 AM.

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We are pleased to announce the “Workshop on Particle Physics and Cosmology 2021”, to take place offline on Nov 26-28, 2021 at the Hidden Cliff Hotel, Jeju.

https://www.hiddencliff.kr/main/main.html

 

 The workshop aims to bring researchers working in the fields of theoretical particle physics and cosmology together to discuss the latest results and exchange ideas.

The workshop will feature contributed presentations from all participants for whom we will support accommodation, and meals (dinner on Nov. 26, 27, breakfast on Nov. 27, 28).

 

Due to the regulation of COVID19, the number of participants will be limited to 45 in total including students, early career researchers, and faculties. 

Please register and arrange your travel to Jeju at your earliest convenience. 

The registration has closed.

travel_guide.pdf

Friday, 26 November

15:00 → 17:30 Session 1

Convener: Seong Chan Park (Yonsei University)

15:00 Self-interacting dark matter with u-channel resonances

We consider a new mechanism for enhancing the self-scattering of dark matter without a light mediator or a sub-GeV dark matter. The mechanism relies on the u-channel resonance from a dark matter particle in models with at least two components of dark matter with self-couplings. We develop the Bethe-Salpeter formalism for obtaining the non-perturbative cross section and the Sommerfeld enhancement factor for two-component dark matter and discuss the implications for dark matter self-scattering and annihilation and a model building with multi-component dark matter.

Speaker: Hyun Min Lee (Chung-Ang University)

Jeju2021-hmlee.pdf

15:30 Constraining Primordial Black Holes with Dwarf Galaxy Heating

Primordial Black Holes (PBH) in the intermediate mass range can be seeds for supermassive black holes and recent LIGO detections of black hole mergers in the mass gap suggest PBH progenitors. I present a novel constraint on the PBH mass fraction spanning PBH masses of 10-10^7 solar masses from thermal equilibrium considerations. A population of PBH in the central region of the dwarf galaxy Leo T will accrete gas from the interstellar medium and emit high energy photons and protons, depositing heat back into the ISM gas. Using semi-analytical accretion disk modeling, we balance the heating and cooling rates of the Leo T gas to derive competitive bounds. We extend our results to spinning PBH with projected jet contribution and to light PBHs with Hawking radiation.

Speaker: Philip Lu (Seoul National University)

Cloud Cooling Bounds IMPBH and Light PBH.pptx

16:00 Self-resonant Dark Matter

we present a novel mechanism for Sommerfeld effect for dark matter interactions without light mediator. Considering two component dark model with triple interaction, we find one of dark matter leads to an u-channel resonance in dark matter elastic scattering.

Speaker: Seongsik Kim (Chung-Ang University)

2021 Nov Jeju WWPC_SeongSikKIm.pdf

16:15 Flux-mediated Dark Matter

We propose a new mechanism to communicate between fermion dark matter and the SM only through the four-form flux. The four-form couplings are responsible for the relaxation of the Higgs mass to the correct value and the initial displacement of the reheating pseudo-scalar field from the minimum. We show that the simultaneous presence of the pseudo-scalar coupling to fermion DM and the flux-induced Higgs mixing gives rise to unsuppressed annihilations of DM into the SM particles at present, whereas the direct detection bounds from XENON1T can be avoided.

Speaker: Ji-Seon Song (Chung-Ang University)

Jeju Workshop-송지선.pdf

16:30 Sensitivities of future atmospheric neutrino experiments to NSI

We explore the impact of neutral-current non-standard neutrino interactions (NSI) on the propagation of atmospheric neutrinos using the future experiments, DUNE and HK as well as the future planned KNO and ORCA neutrino detectors. We study the potential of these experiments to constrain the matter NSI parameters assuming ten years of data taking of atmospheric neutrinos and find the improved upper bounds on NSI parameters. We investigate how muon neutrino survival probability and tau neutrino appearance probability get modified in the presence of NSI parameters. We present the sensitivity of the DUNE, HK, KNO and ORCA detectors to set bounds on the NSI parameters $\epsilon_{\mu \tau}$, $\mid \epsilon_{\mu \mu} - \epsilon_{\tau \tau} \mid$, $\epsilon_{e \mu }$, $\epsilon_{e \tau}$ and $\mid \epsilon_{\mu \mu} - \epsilon_{e e} \mid $ and find that these experiments have significant sensitivities to constrain these parameter. Moreover, we present the expected allowed contour region in the $\delta_{CP}$ and $\epsilon_{e \alpha}$ plane for $\alpha = \mu, \tau$ assuming NSIs exist.

Speaker: Pouya Bakhti (Jeonbuk National University)

Pouya Bakhti_presentation_1.pdf

17:00 Probing non-standard neutrino interactions with low energy neutrino-electron elastic scattering in reactor experiments

Reactor experiments provide an excellent platform to investigate the atomic ionization effects induced by the unexplored neutrino interaction channels. Including the atomic effects in our calculations, we study the neutrino-electron scattering by reactor anti-neutrinos in low-energy electron recoil detectors such as Si/Ge in light of neutrino non-standard interactions with leptons. We find that the atomic and crystal effects in Si/Ge yields a sizable suppression to the neutrino-electron scattering rate when compared to the free-electron approximation. We present our sensitivity results for the light vector and scalar mediator case. The explanation of the excess in the recent Xenon1T result can also be investigated at the reactor experiments since the reactors have a similar energy flux profile to solar neutrinos with characteristic neutrino energies <1 MeV.

Speaker: Sumit Ghosh (KIAS)

Jeju_SG.pdf

17:30 → 19:00 Dinner

19:00 → 20:00 Session 2

Convener: Hang Bae Kim

19:00 Probing diffuse dark matter halos with diffractive lensing of gravitational wave

Cosmological structures at subgalacticscales are pristine testbeds for dark matter(DM) physics. However, they are too diffuse and dark to be visible in any existing observations. In thiswork,wedevelopformalisms for diffractive lensing and show that itcanbeusedto detect diffuseDM halos with chirping gravitational waves(GWs) from massive binary black holes. Assuming Navarro-Frenk-White profile for DM halo, GW detector like Big bang observer is expected to detect such lensing events due to 103−4𝑀⊙halos at a rateof O(10) per year. We also demonstrate how diffractive weak lensing can be used to measure a lens profile.

Speaker: Han-Gil Choi (Seoul National University)

hgchoi_WPPC.pptx

19:30 A reshuffled SIMP dark matter model with U(1)_D to Z_4 symmetry

In this talk, we will demonstrate the redistribution of dark matter mass densities in an UV complete model with U(1)_D to Z_4 symmetry.

Speaker: Shu-Yu Ho (KIAS)

Jeju_ShuYuHo.pdf

Saturday, 27 November

09:30 → 10:30 Session 3

Convener: Sin Kyu Kang

09:30 Is active neutrino Dirac or Majorana?

I will give a nice way to identify neutrinos.

Speaker: Choong Sun Kim (Yonsei University)

Leptonic CPV (for Leptogenesis).pptx

10:00 TBA

Speaker: Siyeon Kim

10:30 → 11:00 Tea Break

11:00 → 12:30 Session 3

Convener: Sin Kyu Kang

11:00 Sterile neutrino dark matter with dipole interactions

Speaker: Ki-Young Choi (SKKU)

SterileDMdiple_Jeju_KYChoi.pdf

11:30 Search for sterile neutrino with light gauge interactions

Speaker: Jongkuk Kim (KIAS)

Jongkuk_Kim.pdf

12:00 Lepton sector in a modular flavor symmetry

I will review a recent development of flavor symmetry introducing a modular symmetry.

Speaker: Hiroshi Okada (APCTP)

okada_27thNov2021.pdf

12:30 → 14:00 Lunch

14:00 → 16:00 Session 4

Convener: Deog Ki Hong

14:00 Festina Lente Bound on Higgs Vacuum Structure and Inflation

The recently suggested Festina-Lente (FL) bound provides a lower bound on the masses of
U(1) charged particles in terms of the positive vacuum energy. Since the charged particle masses in the Standard Model (SM) are generated by the Higgs mechanism, the FL bound provides a testbed of consistent Higgs potentials in the current dark energy-dominated universe as well as during inflation. We study the implications of the FL bound on the UV behavior of the Higgs potential for a miniscule vacuum energy, as in the current universe. We also present values of the Hubble parameter and the Higgs vacuum expectation value allowed by the FL bound during inflation, which implies that the Higgs cannot stay at the electroweak scale during this epoch.

Speaker: Seong Chan Park (Yonsei University)

scp_v2.pdf

14:30 Hubble selection of the weak scale from QCD quantum phase transition

If the strange quark were lighter, QCD phase transition could have been first order. This implies that QCD may have quantum critical points as the Higgs vev v_h is varied from its Standard Model value. We show that inflationary quantum evolution of v_h with the relaxion can drive our universe toward those critical points, realizing the weak scale close to the observed value while explaining its closeness to \Lambda_{\rm QCD}. We first explore quantum critical points of N_f=3 QCD, parameterized by v_h at T=0, and present a basic model for the weak scale. It results in a sharply localized probability distribution of the weak scale, which is critical not to the crossover at zero but to the quantum transition at ~\Lambda_{\rm QCD}.

Speaker: TaeHun Kim (Seoul National University)

TaeHun_Kim.pptx

14:45 Primordial Black Holes and Gravitational Waves in Higgs-$R^2$ Inflation.

Primordial black holes are gaining a renewed interest as a source of various phenomena in our early universe, and are regarded to be appealing probes for the curvature perturbation at small scales. These enhanced curvature perturbations also lead to second order gravitational waves, with many ranges of frequencies within reach of future observations. Here I analyze the curvature perturbation enhancement in the Higgs-$R^2$ model, and present its implications on primordial black holes and gravitational waves.

Speaker: Dhong Yeon Cheong (Yonsei University)

JEJU_PBH_HIGGS_DY_CHEONG .pdf

15:00 Reheating Predictions and Phenomenology from Inflation with Non-minimal Coupling

In the inflationary paradigm, reheating processes have potentially rich phenomenology. First, for observational side, this affects to predictions on cosmological observables. We study effects of reheating on inflationary predictions of models with general non-minimal coupling possessing asymptotically flat potential, including Higgs inflation. We consider wide range of non-minimal coupling in both metric and Palatini formalisms. Second, for the connection of BSM physics, we propose a scenario of spontaneous leptogenesis during the reheating in Higgs inflation, considering two higher order non-renormalizable terms responsible for lepton number violation and spontaneous CPT violation, respectively.

Speaker: Sung Mook Lee (Yonsei University)

WPPC_211127_SMLee.pdf

15:15 General Higgs-sigma models for inflation and its supergravity embedding.

Higgs inflation has drawn attention due to the minimal possibility of the Standard Model Higgs playing the role of the inflation field. However, the large non minimal coupling with gravity leads to unitarity violation. In this talk, we consider a class of models dubbed sigma-models, UV completions to Higgs inflation arising from general higher curvature terms beyond Einstein gravity. We discuss the sigma-Higgs interaction implications for inflation, vacuum stability and the reheating process. Finally, we discuss the embedding of the inflationary potential into a supergravity framework.

Speaker: Adriana Guerrero Menkara (Chung Ang University)

Adriana_Menkara_Day2_Session4.pdf

15:30 Inflation and Supersymmetry Breaking in Higgs-R2 Supergravity

It is known that the Higgs inflation suffers from unitarity problem due to a large non-minimal coupling of Higgs field to Ricci scalar. Recently, it has been clear that introducing a Ricci square term (R2 term) in the Higgs inflation can solve this problem, and provide its UV completion. This model known as Higgs-R2 inflation perfectly agrees with the CMB observation of the Planck result. In this talk, we discuss a supersymmetric embedding of the Higgs-R2 inflation, whcih is desired from a naturalness consideration. We investigate several conditions for the original successful inflation to be kept after supersymmetrization, and also discuss supersymmetry breaking and its phenomenological consequence.

Speaker: Aoki Shuntaro (Chung-ang University)

WPPC2021_ShuntaroAoki.pdf

16:00 → 16:30 Tea Break

16:30 → 18:00 Session 4

Convener: Hyun Min Lee

16:30 Comprehensive study of the light charged Higgs boson in Type-I 2HDM

We study the phenomenological signatures of the light charged Higgs in Type-I 2HDM. The previous studies rely on its production via the decay of top quark into a light charged Higgs boson and a bottom quark. Over random scanning, we obtain the viable parameter space and suggest more efficient production and decay channels.

Speaker: Jeonghyeon Song (Konkuk University)

Song-Jeju.pdf

17:00 Investigating the Long-lived particles and its properties at colliders

Long-lived particles appear in many new physics models.
Especially, the particle with decay length below 1 m can generate various displaced signatures at the colliders and such events are expected to have low background. There are huge opportunities in this lifetime parameter. In this context, we study not only the experimental reach of the LLP searches at colliders (LHC, HL-LHC, Belle II) but also how to reconstruct the event with displaced vertex and missing energy which can provide the understanding for the underlying new physics. We also give challenges and future prospects of the LLP searches.

Speaker: Dong Woo Kang (KIAS)

WPPC2021_DWK.pdf

17:30 See-saw lepton masses and muon g-2 from heavy vector-like leptons

We propose a model for the vector-like lepton to explain the small muon mass by a see-saw mechanism, based on lepton-specific two Higgs doublet models with a local $U(1)'$ symmetry. There is no bare muon mass for a nonzero $U(1)'$ charge of the leptophilic Higgs doublet, so the physical muon mass is generated due to the mixing between the vector-like lepton and the muon after the leptophilic Higgs doublet and the dark Higgs get VEVs. In this scenario, the non-decoupling effects of the vector-like lepton give rise to leading contributions to the muon $g-2$, thanks to the light $Z'$ and the light dark Higgs boson. We discuss various constraints on the model from lepton flavor violation, electroweak precision and Higgs data, as well as collider searches.

Speaker: Kimiko Yamashita (Chung-Ang University)

20211127_kimiko-yamashita_jejuworkshop_pdf.pdf

18:00 → 19:30 Dinner

19:30 → 20:30 Session

Convener: Jeonghyeon Song

19:30 Probing EWPT in 2HDM with Future Lepton Colliders

The electroweak phase transition can be made first order by extending the Standard Model (SM) Higgs sector with extra scalars. In this talk, we focus one the a strong first order electroweak phase transition (SFOEWPT) in the type-I and type-II two Higgs doublet models (2HDM). Through a parameter space scan, we find that SFOEWPT suggests upper limits on the masses of the heavy Higgs 𝑚𝐴/𝐻/𝐻±, which is less than 1 TeV. High temperature expansion and Higgs vacuum uplifting is used for an analytical understanding of our results. We find that sizeable loop corrections require 𝑚𝐴≈𝑚𝐻±>𝑚𝐻 to meet the SFOEWPT condition in the Type-II 2HDM. We also study the possibility of probing SFOEWPT at the one-loop level from Higgs and 𝑍-pole precision measurements at future Higgs \& 𝑍 factories, as well as the future hadron collider.

Speaker: Wei Su (KIAS)

JejuWorkshop_WeiSu.pdf

20:00 Higgs to dimuon discovery using quark/gluon tagging of ISR

In 2020, CMS collaboration reported the significance of 3.0$\sigma$ for the Higgs boson decay to dimuon process. We propose that by using quark/gluon tagging of the initial state radiation(ISR) jets, the significance can be considerably enhanced. We exploit the difference in the fraction of quark/gluon ISR jets of gluon-fusion Higgs signal and its background, Drell-Yan. By conducting multivariate analysis with jet-substructure variables, which have distinct distributions for each quark and gluon jets, we obtain significantly improved significance compared to the result of CMS collaboration.

Speaker: SuBin Han (Seoul National University)

2021-11-27_Jeju_SuBInHan.pdf

Sunday, 28 November

09:00 → 10:30 Session 5

Convener: Okada Hiroshi (APCTP)

09:00 Astrophysical territory of multi-component boosted dark matter

I will talk about the effects of multi-component boosted dark matter in various astrophysical phenomena. Also, its effect to various neutrino experimental and dark matter direct detection experimental results

Speaker: Seodong Shin (Jeonbuk National University)

Jeju2021.pdf

09:30 Millicharged Particles and Dark Matter indirect detection

Various alleged indirect dark matter search signals, such as the 511 keV line from galaxy center or the PAMELA/AMS02 signal, are often challenged by the absence of corresponding signal from dwarf galaxies and/or from the absence of an impact on CMB through delayed recombination. We propose a novel scenario to explain 511 keV signal, that can avoid these bounds based on the decay of dark matter, X, to a pair of intermediate particles C and \bar{C} with a lifetime much greater than the age of the universe. Having a small electric charge, these millicharged particles can be trapped by the galactic magnetic field. Moreover, we discuss how this scenario can provide a solution to AMS02 positron excess based on the decay of dark matter particles into intermediate millicharged particles. Finally, we will discuss how such a small charge can have interesting consequences including a signal in direct dark matter searches.

Speaker: Meshkat Rajaee (Jeonbuk National University)

Jeju_Meshkat_Rajaee.pdf

10:00 Paths to proton stability in grand unification

We explore scenarios within grand unification in which proton decay can be suppressed and possibly eliminated due to novel embeddings of the Standard Model matter fields into irreducible representations of the grand unified group and residual symmetries. The scenarios are based on an $SU(7)$ gauge group, in which the matter fields are embedded within an anomaly-free set of fields that can be realized as a natural subgroup of the fundamental spinor representation of an $SO(14)$ gauge symmetry. Depending on the embedding, proton decay can either be forbidden at tree level and generated via one-loop diagrams, or the proton can be made stable by forcing it to decay channels that must have an even number of leptons, independently of the bosonic content of the theory. We describe the theoretical and phenomenological implications of such scenarios, including their implications for dark matter and neutrino masses.

Speaker: Oleg Popov (KAIST)

WPPC2021_Popov_Oleg.pdf

10:30 → 11:00 Tea Break

11:00 → 13:00 Session 5

Convener: Seong Chan Park (Yonsei University)

11:00 Models for flavor anomalies and dark matter

I will discuss a few models that can accommodate flavor anomalies as well as dark matter of the universe.

Speaker: Pyungwon Ko (KIAS)

Jeju2021_ko.pdf

11:30 cosmic inflation and primordial black holes in the scalar-tensor theory of gravity

Speaker: Gansukh Tumurtushaa

PBHinHG-GansukhT.pdf

12:00 Muonphilic Dark Matter explanation of gamma-ray galactic center excess

The Galactic center gamma-ray excess (GCE) is a long-standing unsolved problem. One of candidate solutions, the dark matter (DM) annihilation, has been recently tested with other astrophysical observations, such as AMS-02 electron-positron spectra, Fermi Dwarf spheroidal galaxies gamma ray data, and so on. It has been claimed that only the DM annihilation to a muon-pair, namely muonphilic DM, is compatible with the null detection of all the corresponding astrophysical measurements [Di Mauro and Winkle (2021)]. On the other hand, a muonphilic DM model may also lead to a signal in the recent muon g-2 measurement or the latest PandaX-4T limit. In this work, we comprehensively study interactions between DM and muon, including different DM and mediator spins. In agreement with GCE (not only 2 μ 2μ but also 4 μ 4μ final states), we test these interactions against all the thermal DM constraints. Our results show that only the parameter space near the mediator resonance region can explain GCE and relic density simultaneously. Regardless of the DM spin, only the interactions with the spin-0 mediator can explain the recent muon g-2 excess on top of GCE, relic density, and other DM and mediator constraints.

Speaker: Chih-Ting Lu (KIAS)

CT_Lu_Muonphilic_DM_WPPC_2021.pdf