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KEK-PH Lectures and Workshops 2020

1 July 2020 to 31 March 2021
Asia/Tokyo timezone

Contribution List

55 out of 55 displayed
  1. 1. Renormalon problem in QCD and a direction to go beyond perturbation theory I
    Dr Hiromasa Takaura (KEK)
    01/07/2020, 11:00

    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....

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  2. 6. Renormalon problem in QCD and a direction to go beyond perturbation theory II
    Dr Hiromasa Takaura (KEK)
    07/07/2020, 11:00

    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....

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  3. 7. Resummation of perturbative series and Resurgence in quantum field theory I
    Prof. Masazumi Honda (YITP)
    08/07/2020, 11:00

    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...

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  4. 8. Resummation of perturbative series and Resurgence in quantum field theory II
    Prof. Masazumi Honda (YITP)
    15/07/2020, 11:00

    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...

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  5. 2. Physics at e+e-collider
    Prof. Michael Peskin (SLAC)
    04/08/2020, 10:00

    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: ...

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  6. 4. Physics at e+e-colliders
    Prof. Michael Peskin
    04/08/2020, 11:30

    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

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  7. 9. Heavy quark pair productions at ILC
    Dr Ryo Yonamine (Tohoku)
    04/08/2020, 13:30

    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,...

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  8. 10. Dark matter detection at future lepton colliders
    Prof. Shigeki Matsumoto (Kavli IPMU)
    04/08/2020, 14:00

    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...

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  9. 13. Early kinetic decoupling of dark matter and the Higgs invisible decay in collider experiments
    Dr Tomohiro Abe (KMI, Nagoya)
    04/08/2020, 14:20

    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...

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  10. 12. SUSY models for the muon g-2 anomaly, and their implications
    Dr Norimi Yokozaki (KEK)
    04/08/2020, 14:40

    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...

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  11. 14. Anomaly Mediation at Future Hadron Colliders
    Dr So Chigusa (KEK)
    04/08/2020, 15:20

    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...

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  12. 15. Higgs self-coupling as a probe of sphaleron properties
    Prof. Shinya Kanemura (Osaka)
    04/08/2020, 15:40

    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...

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  13. 16. Probing μτ flavor-violating solutions for the muon g−2 anomaly at colliders
    Dr Michihisa Takeuchi (KMI, Nagoya)
    04/08/2020, 16:00

    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...

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  14. 5. Lecture1: Basics of Hadron collider
    Dr Zhen Liu (Maryland)
    05/08/2020, 10:00

    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...

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  15. 3. Lecture 2: Advanced topics of Hadron Collider Physics
    Prof. Zhen Liu (Maryland)
    05/08/2020, 11:30

    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...

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  16. 17. Tagging boosted weak gauge bosons with deep learning
    Prof. Cheng-Wei Chiang (National Taiwan University)
    05/08/2020, 13:30

    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...

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  17. 18. Minkowski Functionals for Jet Tagging
    Dr Sung Hak LIM
    05/08/2020, 13:50
  18. 19. Learning Physics at Future e-e+ Colliders with Machine
    Prof. Tao Liu (The Hong Kong University of Science and Technology)
    05/08/2020, 14:10

    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...

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  19. 20. Flavor Physics at Future Z-Factories: $b\to s\tau\tau$ Measurements and Beyond
    Dr Lingfeng Li (HKUST)
    05/08/2020, 14:30

    $b\to s\tau^+\tau^-$ 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...

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  20. 21. Search for lepton-flavor violating processes at LHC
    Prof. Soji Tsuno (KEK)
    05/08/2020, 15:10
  21. 22. Cornering Higgsino at the LHC
    Dr Satoshi Shirai (Kavli IPMU, Tokyo)
    05/08/2020, 15:40

    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...

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  22. 23. Probing long-lived particles at Higgs factories
    Dr Zeren Simon Wang (APCTP)
    05/08/2020, 16:00

    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...

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  23. 24. Searches for new light particles at ILC main beam dump
    Dr Yasuhito Sakaki (KEK)
    05/08/2020, 16:20

    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...

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  24. 29. Direct search of dark matter
    Prof. Kentaro Miuchi (Kobe University)
    13/10/2020, 10:00

    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.

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  25. 31. XENON1T excess in local Z_2 DM models with light dark sector
    Jongkuk Kim (KIAS)
    13/10/2020, 13:00
  26. 32. A model of electroweakly interacting non-abelian vector dark matter
    Kohei Matsushita (Nagoya University)
    13/10/2020, 13:20
  27. 33. Pseudo-Nambu-Goldstone dark matter from gauged $U(1)_{B-L}$ symmetry
    Yoshihiko Abe (Kyoto University)
    13/10/2020, 13:40
  28. 34. Unification for Darkly Charged Dark Matter
    Masaki Yamada (Tohoku University)
    13/10/2020, 14:00
  29. 35. Indirect Search for Secluded Dark Matter with Neutrinos
    Kento Asai (University of Tokyo)
    13/10/2020, 14:50
  30. 36. Dependence of accessible dark matter annihilation cross-sections on the density profiles of dwarf spheroidal galaxies with the CTA
    Nagisa Hiroshima (University of Toyama)
    13/10/2020, 15:10
  31. 37. Non-spherical dark halo structures and J-factor mapping for the Galactic dwarf spheroidals
    Kohei Hayashi (Tohoku University)
    13/10/2020, 15:30
  32. 38. Primordial Black Hole Dark Matter
    Kazunori Kohri (KEK)
    13/10/2020, 15:50
  33. 39. Novel approaches to ultra-low-mass dark matter detection
    Yevgeny Stadnik (Kavli IPMU)
    13/10/2020, 16:40
  34. 40. Stability of Axion Dark Matter-Photon Conversion
    Emi Masaki (Kobe University)
    13/10/2020, 17:00
  35. 41. Axion Supernova-scope
    Natsumi Nagata (University of Tokyo)
    13/10/2020, 17:20
  36. 26. Particle-physics constraints from stars
    Prof. Georg Raffelt (Munich, Max Planck Inst.)
    21/10/2020, 16:00

    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...

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  37. 44. NANOGrav and primordial black holes
    Takahiro Terada (IBS)
    04/11/2020, 13:00
  38. 45. Testing stochastic gravitational wave signals by PBH microlensing
    Sunao Sugiyama (Kavli IPMU, Tokyo)
    04/11/2020, 13:40
  39. 46. NANOGrav and first-order phase transition in the early Universe
    Masaki Yamada (Tohoku)
    04/11/2020, 14:20
  40. 47. Future measurements of stochastic gravitational wave background through pulsar timing by SKA
    Keitaro Takahashi (Kumamoto)
    04/11/2020, 15:00
  41. 42. Gravitational waves from phase transitions at the electroweak scale
    Prof. Mark Hindmarsh (Sussex)
    04/11/2020, 16:00

    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.

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  42. 43. Gravitational waves from first-order phase transitions: Towards a better prediction
    Dr Ryusuke Jinno (DESY)
    04/11/2020, 17:00

    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...

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  43. 48. An on-shell view of four-dimensional blackholes
    Prof. Yu-Tin Huang (NTU)
    01/12/2020, 10:00

    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...

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  44. 49. Introduction to the amplituhedron
    Dr Ryota Kojima (NTU)
    02/12/2020, 10:00

    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...

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  45. 51. BSM Physics with Light Particles
    Prof. Mikhail Shaposhnikov (EPFL)
    04/02/2021, 17:00

    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.

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  46. 52. Fixed target experiments using electron and positron beams
    Yasuhito Sakaki (KEK)
    10/02/2021, 10:00

    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...

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  47. 57. Heavy QCD Axion in $b\to s$ transition
    Kohsaku Tobioka (Florida State University)
    24/03/2021, 13:00
  48. 58. Revisiting electroweak radiative corrections to $b \to s\ell\ell$ in SMEFT
    Daiki Ueda (University of Tokyo)
    24/03/2021, 13:20
  49. 59. Imprint of SUSY in radiative B meson decays
    Keisho Hidaka (Tokyo Gakugei University)
    24/03/2021, 13:40
  50. 60. Lepton flavor violations from soft SUSY breaking terms in modular flavor models
    Takashi Shimomura (Miyazaki University)
    24/03/2021, 14:00
  51. 61. Probing $\mu e \gamma \gamma$ contact interactions with $\mu \to e$ conversion
    Masato Yamanaka (Osaka City University)
    24/03/2021, 14:50
  52. 62. Time evolution of Lepton family Number carried by Majorana Neutrinos
    Takuya Morozumi (Hiroshima University)
    24/03/2021, 15:10
  53. 63. Quark-hadron duality for charm mixing in the 't Hooft model
    Hiroyuki Umeeda (Academia Sinica))
    24/03/2021, 15:30
  54. 55. Filling the gap between inclusive and exclusive processes
    Prof. Shoji Hashimoto (KEK)
    24/03/2021, 16:30

    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...

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  55. 56. Exclusive b -> s mu mu Processes as Precision Probes of the Standard Model
    Dr Danny van Dyk (TUM)
    30/03/2021, 17:00

    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.

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