KEK-PH Lectures and Workshops 2020

1 Jul 2020, 10:00 → 31 Mar 2021, 12:00 Asia/Tokyo

"KEK-PH lectures and workshops" is a form of KEK-PH workshop series at the time of Covid-19.

The annual KEK Theory Meeting on Particle Physics Phenomenology (KEK-PH) covers many topics in Particle Physics and Cosmology, from the Standard Model and models beyond it to particle cosmology and astrophysics. At the time of Covid-19, the KEK theory center is organizing an on-line lecture and workshop series, "KEK-PH lectures and workshops 2020."

 

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1st KEK-PH Lectures on "Renormalon and Resurgence"

Program

https://conference-indico.kek.jp/event/117/timetable/#day-2020-07-01

Lectures

Jul. 1, 7: Dr. Hiromasa Takaura (KEK), "Renormalon problem in QCD and a direction to go beyond perturbation theory"

Jul. 8, 15: Prof. Masazumi Honda (YITP), "Resummation of perturbative series and Resurgence in quantum field theory"

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2nd KEK-PH Lectures and Workshop on "Collider"

Program

https://conference-indico.kek.jp/event/117/timetable/#day-2020-08-04

Lectures

Aug. 4:  Prof. Micheal Peskin (SLAC), "Physics at e+e-collider"

Aug. 5:  Dr. Zhen Liu (Maryland), "Hadron collider Physics"

Workshop

Aug. 4.

 

Ryo Yonamine (ILC, Tohoku) 
Shigeki Matsumoto  (Kavli IPMU, Tokyo)
Tomohiro Abe (KMI, Nagoya) 
Norimi Yokozaki (KEK)  
So Chigusa (KEK)
Shinya Kanemura (Osaka)
Michihisa Takeuchi (KMI, Nagoya)

Aug. 5.

Cheng-Wei Chiang (NTU) 
Sung Hak Lim (KEK)  
Tao Liu (HKUST)  
Lingfeng Li (HKUST)

Soji Tsuno (ATLAS, KEK)  

Satoshi Shirai (Kavli IPMU, Tokyo) 

Zeren Simon Wang (APCTP)
Yasuhito Sakaki  (KEK) 

 

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3rd KEK-PH + KEK-Cosmo Joint Lectures and Workshop on "Dark Matter"

Program

https://conference-indico.kek.jp/event/117/timetable/#day-2020-10-13

Lectures

Oct. 13, 10:00-12:00: Prof. Kentaro Miuchi (Kobe University), "Direct search of dark matter"

Oct. 21, 16:00-18:00: Prof. Georg Raffelt (Munich, Max Planck Inst.), "Particle-physics constraints from stars"

Workshop

Oct. 13, 13:00-17:40

Jongkuk Kim
Kohei Matsushita
Yoshihiko Abe
Masaki Yamada

Kento Asai
Nagisa Hiroshima
Kohei Hayashi
Kazunori Kohri

Yevgeny Stadnik
Emi Masaki
Natsumi Nagata

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4th KEK-PH + KEK-Cosmo Joint Lectures and Workshop on "Gravitational Wave"

Program

https://conference-indico.kek.jp/event/117/timetable/#day-2020-11-04

Lectures

Nov. 4, 16:00-18:00

16:00-17:00: Prof. Mark Hindmarsh (Sussex), "Gravitational waves from phase transitions at the electroweak scale"

17:00-18:00: Dr. Ryusuke Jinno (DESY), "Gravitational waves from first-order phase transitions: Towards a better prediction"

Short Talks

Nov. 4, 13:00-15:30

Takahiro Terada (IBS), "NANOGrav and primordial black holes"
Sunao Sugiyama (Kavli IPMU, Tokyo), "Testing stochastic gravitational wave signals by PBH microlensing"
Masaki Yamada (Tohoku), "NANOGrav and first-order phase transition in the early Universe"
Keitaro Takahashi (Kumamoto), "Future measurements of stochastic gravitational wave background through pulsar timing by SKA"

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5th KEK-PH Lectures on "Amplitude"

Program

https://conference-indico.kek.jp/event/117/timetable/#day-2020-12-01

Lectures

Dec. 1, 10:00-12:00: Prof. Yu-Tin Huang (NTU), "An on-shell view of four-dimensional blackholes"

Dec. 2, 10:00-12:00: Dr. Ryota Kojima (NTU), "Introduction to the amplituhedron"

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6th KEK-PH Lectures on "Long-lived particles"

Program

https://conference-indico.kek.jp/event/117/timetable/#day-2021-02-04

Lectures

Feb. 4, 17:00-18:30 : Prof. Mikhail Shaposhnikov (EPFL), "BSM Physics with Light Particles"

Feb. 10, 10:00-12:00: Dr. Yasuhito Sakaki (KEK), "Fixed target experiments using electron and positron beams"

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7th KEK-PH Lectures and Workshop on "Flavor"

Program

https://conference-indico.kek.jp/event/117/timetable/#day-2021-03-24

Lectures

Mar. 24, 16:30-18:00 : Prof. Shoji Hashimoto (KEK), "Filling the gap between inclusive and exclusive processes"

Mar. 30, 17:00-18:30: Dr. Danny van Dyk (TUM), "Exclusive b -> s mu mu Processes as Precision Probes of the Standard Model"

Workshop

Mar. 24, 13:00-15:50

Kohsaku Tobioka (Florida State University)
Daiki Ueda (University of Tokyo)
Keisho Hidaka (Tokyo Gakugei University)
Takashi Shimomura (Miyazaki University)
Masato Yamanaka (Osaka City University)
Takuya Morozumi (Hiroshima University)
Hiroyuki Umeeda (Academia Sinica)

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Organizers: So Chigusa, Sung Hak Lim, Motoi Endo, Toru Goto, Daisuke Harada, Hiroyuki Ishida, Ryuichiro Kitano, Kazunori Kohri, Ryutaro Matsudo, Hiroki Matsui, Satoshi Mishima, Mihoko M. Nojiri, Hajime Otsuka, Yutaka Sakamura, Toyokazu Sekiguchi, Hiromasa Takaura, Ryo Yokokura, Norimi Yokozaki 

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Wednesday, 1 July

1 Renormalon problem in QCD and a direction to go beyond perturbation theory I

In QCD, perturbation theory is an indispensable tool but is not an ultimate method in the sense that accuracies of perturbative predictions are limited. In particular, the so-called renormalon problem is known that perturbative expansions of observables give divergent series and cause inevitable uncertainties. This problem is becoming more serious from phenomenological aspects in recent years. I first give a review of the renormalon problem. The contents include causes of the divergence of perturbative series and its implications to nonperturbative physics. Subsequently, I discuss a possible direction to overcome the renormalon problem. For this purpose, one has to calculate perturbative contributions compatibly with the operator product expansion so that nonperturbative effects can eventually be included.

Speaker: Dr Hiromasa Takaura (KEK)

Takaura-I.pdf

Tuesday, 7 July

2 Renormalon problem in QCD and a direction to go beyond perturbation theory II

In QCD, perturbation theory is an indispensable tool but is not an ultimate method in the sense that accuracies of perturbative predictions are limited. In particular, the so-called renormalon problem is known that perturbative expansions of observables give divergent series and cause inevitable uncertainties. This problem is becoming more serious from phenomenological aspects in recent years. I first give a review of the renormalon problem. The contents include causes of the divergence of perturbative series and its implications to nonperturbative physics. Subsequently, I discuss a possible direction to overcome the renormalon problem. For this purpose, one has to calculate perturbative contributions compatibly with the operator product expansion so that nonperturbative effects can eventually be included.

Speaker: Dr Hiromasa Takaura (KEK)

Takaura-II.pdf

Wednesday, 8 July

3 Resummation of perturbative series and Resurgence in quantum field theory I

Perturbative series in Quantum Field Theory (QFT) is typically divergent. While there is a standard way to resum divergent series called Borel resummation, it is expected that naive Borel resummation does not work in many QFTs including QCD. Resurgence is often used to cure this kind of situation both in physics and mathematics. In my lecture, I will begin with general expectation on perturbative series in QFT and introduce resurgence with some simple examples. Then I will explain recent attempts to apply resurgence to QFT. Although it is natural to ask whether one can apply resurgence to some realistic theories such as QCD, I do not have a clear answer to the question at this moment because we do not have sufficient data yet. Instead I will discuss what should be done or known to answer the question.

Speaker: Prof. Masazumi Honda (YITP)

resurgence_KEK-PHlectures_day1_share.pdf

Wednesday, 15 July

4 Resummation of perturbative series and Resurgence in quantum field theory II

Perturbative series in Quantum Field Theory (QFT) is typically divergent. While there is a standard way to resum divergent series called Borel resummation, it is expected that naive Borel resummation does not work in many QFTs including QCD. Resurgence is often used to cure this kind of situation both in physics and mathematics. In my lecture, I will begin with general expectation on perturbative series in QFT and introduce resurgence with some simple examples. Then I will explain recent attempts to apply resurgence to QFT. Although it is natural to ask whether one can apply resurgence to some realistic theories such as QCD, I do not have a clear answer to the question at this moment because we do not have sufficient data yet. Instead I will discuss what should be done or known to answer the question.

Speaker: Prof. Masazumi Honda (YITP)

resurgence_KEK-PHlectures_day2_share.pdf

Tuesday, 4 August

KEK-PH collider: Lecture:Physics at e+e-collider(Prof. Michael Peskin)

Convener: Mihoko NOJIRI (Professor)

5 Physics at e+e-collider

Part 1
General introduction: Why do we need new physics beyond the SM?
General introduction: processes in e+e- as a function of energy; run plan of the ILC
Higgs boson: SM predictions for the decay rates and properties -- and, brief review of LHC measurements
Higgs boson: BSM effects on the Higgs couplings
Higgs boson: aspects of the experimental study in e+e-
Higgs boson: global fit of e+e- data in the context of SMEFT

Speaker: Prof. Michael Peskin (SLAC)

ILClecturesatKEK-2020-1.pdf

6 Physics at e+e-colliders

Part 2.
e+e- -> 2 fermion reactions at e+e- colliders, s-channel resonance and compositeness searches
top quark: general theoretical orientation
top quark: threshold region
top quark: continuum region
top quark: possible BSM effects and tests of these
e+e- at high energy: e+e- -> t tbar h
e+e- at high energy e+e- -> hh + X
the long future of the ILC laboratory

Speaker: Prof. Michael Peskin

ILClecturesatKEK-2020-2.pdf

KEK-PH collider: (workshop)

Convener: Mihoko NOJIRI (Professor)

7 Heavy quark pair productions at ILC

We expect the ILC with polarized beams will shed light on the chiral structures of the electroweak couplings to all fermions. In the experimental viewpoint, the key of such measurements is to discriminate between fermion and anti-fermion in pair production events. In this talk, I will report recent developments and what we have achieved so far based on the studies within the ILD collaboration, especially for t-, b-, and c-quark pair productions.

Speaker: Dr Ryo Yonamine (Tohoku)

yonamine20200804.pdf

8 Dark matter detection at future lepton colliders

Future lepton colliders are now intensively discussed around the world, and we have so far four proposals of the colliders; one from Asia (ILC and CEPC) and the other from Europe (FCC-ee and CLIC). The main goal of the colliders at the first stage (s1/2 = 240-250 GeV) is to precisely measure known Higgs couplings to tackle the problem of the electroweak symmetry breaking. On the other hand, it is also interesting to discuss whether other new physics signals, in particular dark matter’s, can be detected or not. In this talk, I would like to talk about how important roles future lepton colliders can play to detect dark matter.

Speaker: Prof. Shigeki Matsumoto (Kavli IPMU)

Matsumoto.pptx

9 Early kinetic decoupling of dark matter and the Higgs invisible decay in collider experiments

We revisit the Higgs-to-invisible decay ratio in Higgs-portal dark matter models. The Higgs-to-invisible decay searches are powerful probes of the models with increasing sensitivity in upcoming colliders. Close to the mass threshold of a Higgs decay into a pair of DM particles, the coupling value is expected to be very small in order to be compatible with the observed value of the thermal relic abundance. This small coupling perfectly fits with the current status of Higgs-to-invisible constraints and direct detection experiments, such as the XENON1T experiment. At the same time, the small coupling implies a lower DM scattering rate with particles in the early Universe plasma. The suppression of the scattering rate makes the kinetic decoupling happens earlier. Thus, the standard assumption in many relic abundance computations, namely the local thermal equilibrium, is not justified during the freeze-out process. We reanalyze Higgs-portal DM models, such as the Scalar-Singlet and a fermion DM model, taking the new effect of early kinetic decoupling in the relic abundance computation into account. Our results show that a larger value of the DM coupling to the Higgs is allowed. Therefore, current and future Higgs-to-invisible decay searches can generically probe more of the parameter space than previously expected.

Speaker: Dr Tomohiro Abe (KMI, Nagoya)

TomohiroAbe.pdf

10 SUSY models for the muon g-2 anomaly, and their implications

The muon g-2 anomaly is an important guide towards new physics beyond the Standard Model as it indicates new particles lighter than O(100) GeV. Supersymmetric standard model is an attractive candidate explaining the anomaly since it also solves other important puzzles: the hierarchy problem, charge quantization and dark matter nature. In this talk, I would like to show that, by considering existent constraints, the viable scenario is almost fixed, which can be tested at the high luminosity LHC.

Speaker: Dr Norimi Yokozaki (KEK)

11 Anomaly Mediation at Future Hadron Colliders

We discuss prospects of studying models with anomaly mediated
supersymmetry breaking at future hadron colliders with centre-of-mass
energy of 100 TeV. In such a class of models, charged Wino becomes
long-lived with its decay length of ∼ 6 cm, and the charged Wino
tracks may be identified in particular by the inner pixel detector;
the charged Wino tracks can be used not only for the discrimination of
standard model backgrounds but also for the event reconstructions. We
show that precise determinations of the Bino, Wino, and gluino masses
are possible at the FCC. For such measurements, information about the charged Wino tracks, including the one about the velocity of the charged Wino using the time of the hit at the pixel detector, is crucial. With the measurements of the gaugino masses in the pure gravity mediation model, we have an access to more fundamental parameters like the gravitino mass. We also show that the lifetime of charged Wino may be measured by using the information about the distribution of the flight lengths of charged Winos. We propose a procedure for the lifetime determination and show how the accuracy
changes as we vary the mass spectrum of superparticle. We also discuss the effects of the detector layouts on the lifetime determination.

Speaker: Dr So Chigusa (KEK)

12 Higgs self-coupling as a probe of sphaleron properties

Sphaleron is a non-perturbative solution of electroweak gauge theories, which is crucially important for various scenarios of baryogenesis. In many of new physics models, the deviation in the sphaleron energy from the standard-model prediction is proportional to that in the triple Higgs boson coupling with opposite signs. This interesting relation would be useful to determine the sphaleron property by measuring the Higgs self-coupling at future collider experiments.

Speaker: Prof. Shinya Kanemura (Osaka)

13 Probing μτ flavor-violating solutions for the muon g−2 anomaly at colliders

The discrepancy between the measured value and the Standard Model prediction of the muon anomalous magnetic moment is one of the most important issues in the particle physics. It is known that introducing a mediator boson X with the μτ lepton flavor violating (LFV) couplings is one good solution to explain the discrepancy, due to the τ mass enhancement in the one-loop correction. We study the signal of this model, i.e. the same-sign leptons, at the LHC and at the Belle II, assuming the flavor-diagonal couplings are suppressed. We show that the Belle II experiment is highly sensitive to the scenario in the mediator mass range of {\cal O}(1-10)~GeV, using the e+e− to \mu \tau \mu \tau process induced by the X.

Speaker: Dr Michihisa Takeuchi (KMI, Nagoya)

Wednesday, 5 August

KEK-PH collider: Lecture: Basics of Hadron Collider Physics(Dr. Zhen Liu)

14 Lecture1: Basics of Hadron collider

Lecture 1: Basics of Hadron Collider Physics
Intro to colliders
Parton distribution function
Kinematics
Discovery of the Higgs boson

I will introduce the basic concepts of hadron collider physics in the first part of the lecture and discuss a few advanced topics in the second part of the lecture. The goal is to let the audience get familiar with the key concepts/methodology of hadron collider physics, such as the parton distribution function and kinematical considerations. With these basic concepts, we can build a picture of the relevant processes at hadron colliders and have a deep appreciation of the endeavor of the discovery of the Higgs boson, and get prepared for quantitative assessment of physics potentials at hadron colliders. In the second half of the lecture, we will continue the discussion to precision physics, as well as some rudimentary understanding of statistics. If time permits, the basics of currently very active research topic of long-lived particles at colliders and satellite experiments will be introduced. Finally, I will sketch a longer-term picture of future collider program and physics.

Speaker: Dr Zhen Liu (Maryland)

Hadron_Collider_Physics_2Hrs_KEK_current.pdf

KEK-PH collider: Lecture Advanced topics of Hadron Collider Physics (Dr. Zhen Liu)

Convener: Mihoko NOJIRI (Professor)

15 Lecture 2: Advanced topics of Hadron Collider Physics

A bit of Statistics
Precision: Jets, Higher-order corrections, more kinematics, and machine learning
Long-Lived Particles
Future hadron colliders (physics)

I will introduce the basic concepts of hadron collider physics in the first part of the lecture and discuss a few advanced topics in the second part of the lecture. The goal is to let the audience get familiar with the key concepts/methodology of hadron collider physics, such as the parton distribution function and kinematical considerations. With these basic concepts, we can build a picture of the relevant processes at hadron colliders and have a deep appreciation of the endeavor of the discovery of the Higgs boson, and get prepared for quantitative assessment of physics potentials at hadron colliders. In the second half of the lecture, we will continue the discussion to precision physics, as well as some rudimentary understanding of statistics. If time permits, the basics of currently very active research topic of long-lived particles at colliders and satellite experiments will be introduced. Finally, I will sketch a longer-term picture of future collider program and physics.

Speaker: Prof. Zhen Liu (Maryland)

KEK-PH collider: (workshop)

Convener: Mihoko NOJIRI (Professor)

16 Tagging boosted weak gauge bosons with deep learning

We demonstrate that the classification of boosted, hadronically-decaying weak gauge bosons can be significantly improved over traditional cut-based and BDT-based methods by using deep learning and the jet charge variable. We construct binary taggers for W+ vs. W− and Z vs. W discrimination, as well as an overall ternary classifier for W+/W−/Z discrimination. We construct both ordinary and new composite CNNs. The method enhances the physics potential in SM measurements and searches for new physics that is sensitive to the electric charge of weak gauge bosons.

Speaker: Prof. Cheng-Wei Chiang (National Taiwan University)

KEK-PH 2020 - Chiang.pdf

17 Minkowski Functionals for Jet Tagging

Speaker: Dr Sung Hak LIM

18 Learning Physics at Future e-e+ Colliders with Machine

Information deformation and loss in jet clustering are one of the major limitations for precisely measuring hadronic events at future e−e+ colliders. Because of their dominance in data, the measurements of such events are crucial for advancing the precision frontier of Higgs and electroweak physics in the next decades. In a recent arXiv paper (https://arxiv.org/pdf/2004.15013.pdf), the speaker and his collaborators showed that this difficulty can be well-addressed by synergizing the event-level information into the data analysis, with the techniques of deep neutral network. In relation to that, they introduced a CMB-like observable scheme, where the event-level kinematics is encoded as the Fox-Wolfram (FW) moments at leading order and multi-spectra at higher orders. Then they developed the classifiers in two ways to achieve this goal: jet-level with the FW moments and brute-force event-level. As an application, these classifiers were applied to measuring Higgs decay width at e−e+ colliders, with the data of 5ab−1@240GeV. The precision obtained is significantly better than the baseline ones presented in documents. In this talk, the speaker will give an overview on these aspects and discuss their potential impacts for future collider-physics study.

Speaker: Prof. Tao Liu (The Hong Kong University of Science and Technology)

19 Flavor Physics at Future Z-Factories: $b\to s\tau\tau$ Measurements and Beyond

$b\to s\tau^+\tau^-$ measurements are highly motivated for addressing lepton-flavor-universality(LFU)-violating puzzles such as $R_{K^{(\ast)}}$ anomalies. The anomalies of $R_{D^{(*)}}$ and $R_{J/\psi}$ further strengthen their necessarity and significance, given that the LFU-violating hints from both involve the third-generation leptons directly. $Z$ factories of future $e^-e^+$ colliders stand at a great position to conduct such measurements, because of their relatively high production rates and reconstruction efficiency for $B$ mesons at $Z$ pole. To fully explore this issue, we pursue a sensitivity study for four $b\to s\tau^+\tau^-$ benchmark channels, namely, $B^0\to K^{\ast 0} \tau^+ \tau^-$, $B_s\to\phi \tau^+ \tau^-$, $B^+ \to K^+ \tau^+ \tau^- $ and $B_s \to \tau^+ \tau^-$, at the future $Z$ factories. A scheme of $B$-meson reconstruction mainly based on detector tracking system is developed for this purpose. The simulations indicate that at Tera-$Z$ the branching ratios of the first three channels can be measured with a precision of $\mathcal O(10^{-7})$ and that of $B_s \to \tau^+ \tau^-$ with a precision of $\mathcal O(10^{-5})$. The interpretation of these results in effective field theory is presented.

Speaker: Dr Lingfeng Li (HKUST)

20 Search for lepton-flavor violating processes at LHC

Speaker: Prof. Soji Tsuno (KEK)

kek_theoryws_08.05.2020.soshi.pdf

21 Cornering Higgsino at the LHC

A Higgsino-like particle is an attractive candidate for the WIMP dark matter. Thanks to the electroweak interaction, the production cross section of the Higgsino at the LHC is rather high. However, the huge Standard Model background prevents the Higgsino discovery, and the present LHC sensitivity can be even worse than the LEP result in some parameter region. In this talk, I discuss a new search strategy to explore such a parameter region by utilizing exotic tracks from the charged Higgsino: soft displaced track and disappearing track.

Speaker: Dr Satoshi Shirai (Kavli IPMU, Tokyo)

higgsino.pdf

22 Probing long-lived particles at Higgs factories

We study displaced vertex signatures of long-lived particles (LLPs) from exotic Higgs decays in the context of a Higgs-portal model and a neutral-naturalness model at the circular electron positron collider (CEPC) and future circular collider e+ e− (FCC-ee). Such two models feature two representative mass ranges for LLPs, which show very different behavior in their decay signatures. The Higgs-portal model contains a very light sub-GeV scalar boson stemming from a singlet scalar field appended to the Standard Model. Such a light scalar LLP decays into a pair of muons or pions, giving rise to a distinctive signature of collimated muon-jet or pion-jet, thanks to the sub-GeV mass. On the other hand, the neutral-naturalness model, e.g., folded supersymmetry, predicts the lightest mirror glueball of mass O(10)  GeV, giving rise to long decays with a large transverse impact parameter because of the relatively large mass. Utilizing such distinct characteristics to remove the background, we estimate the sensitivities of searches for light scalar bosons and mirror glueballs at the CEPC and FCC-ee. We find either complementary or stronger coverage compared to the previous results in the similar contexts.

Speaker: Dr Zeren Simon Wang (APCTP)

slides_ZSW.pdf

23 Searches for new light particles at ILC main beam dump

The International Linear Collider (ILC) is the highest-priority next collider as a Higgs factory. In the linear collider, almost all accelerated particles that do not interact strongly at the collision point are not recycled and are all thrown into beam dumps, which is very different from the case of circular colliders. Therefore, a beam dump experiment in the linear collider can be performed in parallel with the main experiment, which has a great advantage in terms of statistics. In this study, we estimate the detection sensitivity to new light particles that interacts not only to primary electron beams but also to secondary photons, electrons, positrons, and muons in the ILC beam dump. This study demonstrates that the ILC beam dump experiment has an enhanced sensitivity to axion-like particles and leptophilic dark sectors by an order of magnitude compared with previous experiments and other future beam dump experiments.

Speaker: Dr Yasuhito Sakaki (KEK)

Tuesday, 13 October

KEK-PH + KEK-Cosmo DM: Lecture

Convener: Motoi Endo

24 Direct search of dark matter

Direct search of dark matter is expanding its search phase space. This lecture will cover the concepts, current status, and prospects of the dark matter direct searches including related topics.

Speaker: Prof. Kentaro Miuchi (Kobe University)

miuchi_20201007_KEK.pdf

KEK-PH + KEK-Cosmo DM: Workshop

Convener: Motoi Endo

25 XENON1T excess in local Z_2 DM models with light dark sector

Speaker: Jongkuk Kim (KIAS)

KEK_JKKim.pdf

26 A model of electroweakly interacting non-abelian vector dark matter

Speaker: Kohei Matsushita (Nagoya University)

KoheiMatsushita.pdf

27 Pseudo-Nambu-Goldstone dark matter from gauged $U(1)_{B-L}$ symmetry

Speaker: Yoshihiko Abe (Kyoto University)

28 Unification for Darkly Charged Dark Matter

Speaker: Masaki Yamada (Tohoku University)

KEK-ph-Yamada.pdf

14:20 Break

29 Indirect Search for Secluded Dark Matter with Neutrinos

Speaker: Kento Asai (University of Tokyo)

KEK-PH workshops slide (Asai).pdf

30 Dependence of accessible dark matter annihilation cross-sections on the density profiles of dwarf spheroidal galaxies with the CTA

Speaker: Nagisa Hiroshima (University of Toyama)

KEK-PH_DM_20201013.pdf

31 Non-spherical dark halo structures and J-factor mapping for the Galactic dwarf spheroidals

Speaker: Kohei Hayashi (Tohoku University)

KEKDM_20201013_KH.pdf

32 Primordial Black Hole Dark Matter

Speaker: Kazunori Kohri (KEK)

Kohri-KEK-PH+KEK-Cosmo20201013.pdf

16:10 Break

33 Novel approaches to ultra-low-mass dark matter detection

Speaker: Yevgeny Stadnik (Kavli IPMU)

Stadnik_2020_October-KEK_v2.pdf

34 Stability of Axion Dark Matter-Photon Conversion

Speaker: Emi Masaki (Kobe University)

35 Axion Supernova-scope

Speaker: Natsumi Nagata (University of Tokyo)

20201013.pdf

Wednesday, 21 October

KEK-PH + KEK-Cosmo DM: Lecture

Convener: Motoi Endo

36 Particle-physics constraints from stars

Stars can be powerful laboratories to constrain the properties of low-mass particles such as neutrinos, axions, dark photons, low-mass dark-matter candidates, and others. This lecture will mainly focus on the back-reaction on stellar properties caused by the emission of new particles, so we will explain some of the basics of stellar evolution theory. We will also review some old and new limits that are of particular interest at the particle-physics "intensity frontier".

Speaker: Prof. Georg Raffelt (Munich, Max Planck Inst.)

KEK-Raffelt.pdf

KEK-Raffelt.pptx

Wednesday, 4 November

KEK-PH + KEK-Cosmo GW: Short Talk

Convener: Motoi ENDO

37 NANOGrav and primordial black holes

Speaker: Takahiro Terada (IBS)

NANOGrav_PBH.pdf

38 Testing stochastic gravitational wave signals by PBH microlensing

Speaker: Sunao Sugiyama (Kavli IPMU, Tokyo)

sunaosugiyamaKEK2020.pdf

39 NANOGrav and first-order phase transition in the early Universe

Speaker: Masaki Yamada (Tohoku)

KEK-GW-v1.pdf

40 Future measurements of stochastic gravitational wave background through pulsar timing by SKA

Speaker: Keitaro Takahashi (Kumamoto)

201104_Takahashi.pdf

KEK-PH + KEK-Cosmo GW: Lecture

Convener: Motoi ENDO

41 Gravitational waves from phase transitions at the electroweak scale

In extensions of the Standard Model of particle physics, this could have been a first order phase transition, at about 10 picoseconds after the Big Bang. I will discuss the dynamics of the transition, the characteristic spectrum of gravitational radiation, and the prospects for observing the radiation at the future space-based gravitational wave detector LISA.

Speaker: Prof. Mark Hindmarsh (Sussex)

G-Waves 2020 KEK.pdf

42 Gravitational waves from first-order phase transitions: Towards a better prediction

In the upcoming decades, gravitational waves (GWs) will be an important tool in probing the early Universe and in testing high energy physics. In this lecture I will review GW production in cosmological first-order phase transitions, putting more emphasis on analytic understanding of the process. The structure of the lecture will be:
- Basics of GW production in the early Universe
- GW production in first-order phase transitions: conditions for producing large amount GWs & particle models satisfying these conditions
- Three GW sources in first-order phase transitions: bubble collisions, sound waves, turbulence
- Towards better prediction of the signal: analytic vs. numerical
- Recent hot topic(s)

Speaker: Dr Ryusuke Jinno (DESY)

KEK.key.7z

KEK.pdf

Tuesday, 1 December

KEK-PH Amplitude: Lecture

Convener: Ryuichiro Kitano (KEK)

43 An on-shell view of four-dimensional blackholes

In this lecture, I will introduce massive spinor helicity formalism developed in 1709.04891, and explore the electromagnetic/gravitational interactions of high spin particles. We will define, kinematically, minimal coupling for particles of arbitrary spin. While there are no known elementary particles beyond spin-2, we will demonstrate that these minimal coupling the multiple spin-moments of rotating black holes. This particle like description of black hole dynamics is a reflection of the no hair theorem.

Speaker: Prof. Yu-Tin Huang (NTU)

Wednesday, 2 December

KEK-PH Amplitude: Lecture

Convener: Ryuichiro Kitano (KEK)

44 Introduction to the amplituhedron

Recent years have revealed a variety of mathematical and physical structures underlying scattering amplitudes, with redefinitions of scattering amplitudes where the usual principles of locality and unitarity are derivative from geometry. The amplituhedron is one of the examples, a purely geometric object which gives scattering amplitudes of planar N=4 SYM. All tree-level amplitudes and all-loop integrands correspond to the differential forms with logarithmic singularities on the boundaries of the amplituhedron. In this lecture, I will give a review of scattering amplitudes in planar N-4 SYM first. After this, I will explain the definition of the amplituhedron and see how to obtain scattering amplitudes from this geometric object.

Speaker: Dr Ryota Kojima (NTU)

KEKPH.pdf

Thursday, 4 February

KEK-PH Long-lived particles: Lecture

Convener: Dr Ishida Hiroyuki (KEK)

45 BSM Physics with Light Particles

I will discuss the motivations for physics beyond the Standard Model below the Fermi scale, resulting in the existence of feebly interacting long-lived particles. The experimental prospects to search for these particles will be outlined.

Speaker: Prof. Mikhail Shaposhnikov (EPFL)

KEK2021_Shaposhnikov.pdf

Wednesday, 10 February

KEK-PH Long-lived particles: Lecture

Convener: Prof. Mihoko Nojiri (KEK)

46 Fixed target experiments using electron and positron beams

Now that new heavy particles have not been found at the LHC, focusing on light and weakly interacting new particles is one direction to go. Fixed target experiments using accelerators play a part in this. I will explain the basics of the phenomena in fixed target experiments, and how to calculate the number of signal on a target induced by e+ e- beams. Trends in some fixed-target experiments will be introduced. I will discuss a few ideas for fixed target experiments at the ILC, and hope
that this talk will encourage people to think about the possibility of experiments other than the collider experiment at the ILC site.

Speaker: Yasuhito Sakaki (KEK)

Wednesday, 24 March

KEK-PH Flavor: Workshop

Conveners: Mihoko Nojiri (KEK), Ryuichiro Kitano (KEK)

47 Heavy QCD Axion in $b\to s$ transition

Speaker: Kohsaku Tobioka (Florida State University)

Tobioka.pdf

48 Revisiting electroweak radiative corrections to $b \to s\ell\ell$ in SMEFT

Speaker: Daiki Ueda (University of Tokyo)

Ueda.pdf

49 Imprint of SUSY in radiative B meson decays

Speaker: Keisho Hidaka (Tokyo Gakugei University)

Hidaka.pdf

50 Lepton flavor violations from soft SUSY breaking terms in modular flavor models

Speaker: Takashi Shimomura (Miyazaki University)

Shimomura.pdf

14:20 Break

51 Probing $\mu e \gamma \gamma$ contact interactions with $\mu \to e$ conversion

Speaker: Masato Yamanaka (Osaka City University)

Yamanaka.pdf

52 Time evolution of Lepton family Number carried by Majorana Neutrinos

Speaker: Takuya Morozumi (Hiroshima University)

Morozumi-v2.pdf

53 Quark-hadron duality for charm mixing in the 't Hooft model

Speaker: Hiroyuki Umeeda (Academia Sinica))

Umeeda.pdf

KEK-PH Flavor: Lecture

Convener: Hiromasa Takaura (KEK)

54 Filling the gap between inclusive and exclusive processes

Computation of QCD processes is always hard. The use of lattice QCD is limited to low-lying hadronic (often single-particle) states, so that only exclusive processes can be computed. Perturbation theory, plus operator product expansion, is used for high-energy processes for which the final states are not specified, or summed over all possible states, i.e. inclusive processes. There are annoying cases, where two analyses are mutually contradictory, as seen in the |Vcb| and |Vub| determinations. They suggest that there remain some unknown systematic effects in either or both analyses. In this talk I argue that one can construct a theoretical method that can treat both cases in principle, by extending the lattice QCD approach.

Speaker: Prof. Shoji Hashimoto (KEK)

Hashimoto.pdf

Tuesday, 30 March

KEK-PH Flavor: Lecture

Convener: Satoshi Mishima (KEK)

55 Exclusive b -> s mu mu Processes as Precision Probes of the Standard Model

I will provide a review of the theoretical basis of predictions for exclusive b -> s mu mu processes within the Standard Model and beyond. I will then discuss how present phenomenological studies of these decays are carried out, what improvements are forthcoming, and how the results should be interpreted.

Speaker: Dr Danny van Dyk (TUM)

DannyVanDyk.pdf