Pascal Naidon, RIKEN
From the Yukawa to the Efimov attraction
Meeting room 3, Kenkyu honkan 1F
The Yukawa attraction (screened 1/r interaction) is known to arise between two particles exchanging bosons, such as nucleons exchanging mesons. On the other hand, at the three-body level, the Efimov attraction (1/r^2 three-body interaction) can emerge from resonant two-body interactions, leading to the existence of the famous Efimov three-body bound states. In this talk, I will first review the Efimov attraction from its theoretical discovery in 1970 to its most recent experimental confirmations. I will then show how the mediated interaction between two particles immersed in a Bose-Einstein condensate can go from the Yukawa attraction to the Efimov attraction.
Holger Motz, ICSEP, Waseda University
[Cosmophysics Seminar] Methods and Prospects for Science Analysis of CALET Data
Seminar room, Kenkyu honkan 3F, slides (kek.jp only) The ISS based CALET (Calorimetric Electron Telescope) detector is directly measuring the energy spectrum of electron+positron cosmic rays up to 20 TeV with an expected energy resolution of 2%. With an estimated proton rejection capability of 1 : 10^5 and an aperture of approximately 1200 cm^2 sr, it will provide good statistics even well above one TeV. This precise spectrum is going to be analysed for signatures from nearby astrophysical sources such as pulsars and supernova remnants (SNR), as well as from Dark Matter annihilation and decay.
The ISS based CALET (Calorimetric Electron Telescope) detector is directly measuring the energy spectrum of electron+positron cosmic rays up to 20 TeV with an expected energy resolution of 2%. With an estimated proton rejection capability of 1 : 10^5 and an aperture of approximately 1200 cm^2 sr, it will provide good statistics even well above one TeV. This precise spectrum is going to be analysed for signatures from nearby astrophysical sources such as pulsars and supernova remnants (SNR), as well as from Dark Matter annihilation and decay.
In this presentation I will give an overview of the CALET project and its current status, as well as show possible methods to analyse the data for selected physics cases.
Pulsars and Dark Matter are candidates for the postulated extra source emitting an equal amount of electrons and positrons that is regarded as the origin of the positron excess. Assuming a single pulsar is the extra source, the limits on a potential additional component from Dark Matter annihilation in the galactic halo expected to be obtained from 5 years of CALET observation are presented. It is shown that CALET could significantly improve upon current limits, especially for Dark Matter candidates with a large fraction of annihilation directly into electron+positron, such as the LKP (Lightest Kaluza-Klein particle).
As a possible case of a Dark Matter only explanation of the positron excess, Dark Matter decaying in a 3-particle leptonic mode was studied, as it is not constrained by anti-proton measurements and multiple theories predict suitable Dark Matter candidates. Based on the expected signal and background in CALET, the potential to discern the signatures of this decay from a pulsar being the extra source is shown.
Furthermore, the influence of a nearby SNR as an additional spectrum component in the TeV region and the prospects of using anisotropy information to identify cosmic rays originating from nearby astrophysical sources are discussed.
Hidehiko Shimada, Okayama Institute for Quantum Physics
Membrane interaction and a three-dimensional analog of Riemann surfaces
Seminar room, Kenkyu honkan 3F
It is an important problem to understand whether the matrix model of M-theory contains the splitting(-joining) interactions of membranes. In the talk, I will discuss the splitting processes in the pp-wave matrix model, which are certain tunnelling processes. After a brief discussion of the relation to the ABJM theory via the AdS/CFT correspondence, I will show that the BPS instanton equations governing such processes are equivalent to the three-dimensional Laplace equation, under an approximation which is valid when the matrix size is large. I will further show that the solution which corresponds to a splitting process is not defined on R^3, but rather on a space which is constructed by stitching two R^3’s, in a manner analogues to the construction of Riemann surfaces. I will also show plots, constructed using explicit solutions to the Laplace equation, which capture explicitly the behaviours of membranes in the splitting processes. The talk will be based on arxiv:1508.03367, done in collaboration with Stefano Kovacs (Dublin IAS) and Yuki Sato (Chulalongkorn Univ., Bangkok).
Ryo Suzuki, ICTP-SAIFR
Superconformal bootstrap of N=4 Super Yang-Mills and average anomalous dimensions
Seminar room, Kenkyu honkan 3F
Correlation functions of a conformal field theory (CFT) can be constructed from two- and three-point functions. However, the planar four-point functions of a large Nc CFT cannot be recovered by the planar two- and three-points. We apply the superconformal block decomposition to the four-point functions of N=4 SYM, and extracted the non-planar information of multi-trace operators. In addition, we identified non-scalar superconformal primary fields which contribute to the OPE limit. This work is based on collaboration with Yusuke Kimura (OIQP).
Teppei Kitahara, Karlsruhe Institute of Technology
Recent progress on CP violation in K to pi pi decays in the SM and SUSY solution
Seminar Room, Kenkyu-honkan 3F Recent progress in the determination of hadronic matrix elements has revealed a tension between the measured value of epsilon’/epsilon, which quantifies direct CP-violation in K to pi pi decays, and the Standard-Model (SM) prediction. On the other hand, the standard analytic solution of the next-to-leading order (NLO) renormalization group (RG) evolution for the DeltaS = 1 Wilson coefficients suffers from several singularities. In the first part of this talk, we will introduce a singularity-free analytic solution of the RG evolution, and give a new prediction value of the epsilon’/epsilon in the SM at the NLO, which also implies the epsilon’ discrepancy. In the second part, we will show that it is possible to cure the epsilon’ discrepancy in the Minimal Supersymmetric Standard Model with squark masses above 3 TeV without overshooting epsilon. This solution exploits two features of supersymmetry, the possibility of large isospin-breaking contributions (enhancing epsilon’) and the Majorana nature of gluinos (permitting a suppression of epsilon). Our solution involves no fine-tuning of CP phases or other parameters.
Recent progress in the determination of hadronic matrix elements has revealed a tension between the measured value of epsilon’/epsilon, which quantifies direct CP-violation in K to pi pi decays, and the Standard-Model (SM) prediction. On the other hand, the standard analytic solution of the next-to-leading order (NLO) renormalization group (RG) evolution for the DeltaS = 1 Wilson coefficients suffers from several singularities. In the first part of this talk, we will introduce a singularity-free analytic solution of the RG evolution, and give a new prediction value of the epsilon’/epsilon in the SM at the NLO, which also implies the epsilon’ discrepancy. In the second part, we will show that it is possible to cure the epsilon’ discrepancy in the Minimal Supersymmetric Standard Model with squark masses above 3 TeV without overshooting epsilon. This solution exploits two features of supersymmetry, the possibility of large isospin-breaking contributions (enhancing epsilon’) and the Majorana nature of gluinos (permitting a suppression of epsilon). Our solution involves no fine-tuning of CP phases or other parameters.
This talk is based on
arXiv:1604.07400 and
arXiv:1607.06727.
Kaori Fuyuto, Saga Univ
Verifiability of electroweak baryogenesis in an extended Standard Model
Seminar room, Kenkyu honkan 3F
We discuss verifiability of electroweak baryogenesis in an extended Standard Model, where an extra Higgs doublet, a real singlet and electroweak-interacting fermions are added. In the model, while the real singlet plays a role in having first order electroweak phase transition, a new CP-violating source is supplied by interactions between bubble walls and new fermions. It is shown that the parameter region for the successful BAU can be verified by Higgs physics and electric dipole moments of electron and nucleons in near future.
Kazuki Sakurai, Durham Univ.
Search for Sphalerons: LHC vs. IceCube
Meeting room 1, Kenkyu honkan 1F
In a recent paper, Tye and Wong (TW) have argued that sphaleron-induced transitions in high-energy interactions should be enhanced compared to previous calculations, based on a construction of a Bloch wave function in the periodic sphaleron potential and the corresponding pass band structure. In this talk, I present our resent work studying future prospects of observing sphaleron transitions at high energy hadron colliders and IceCube, based on TW results. I first discuss the production rate and possible signatures of the sphaleron-induced processes at high energy hadron colliders. We recast the early ATLAS Run-2 search for microscopic black holes to constrain the rate of sphaleron transitions at 13 TeV LHC. In the second half of the talk, I will discuss the possibility of observing sphaleron transitions induced by cosmogenic neutrinos at IceCube. I calculate the sphaleron event rate at IceCube and discuss the signature of such events. Finally I compare the performance of the sphaleron searches at the LHC and IceCube and find complementarity of these experiments.
Wen Yin, Tohoku Univ.
Novel Approach to Fine-tuned Supersymmetric Standard Models, and the Explanation of the Muon Anomalous Magnetic Dipole Moment Anomaly
Meeting room 1, Kenkyu honkan 1F, slides (kek.jp only) I will propose an analyzing method for supersymmetric standard models with some amount of fine tuning. Applying this method to a non-universal Higgs masses model, I will show a new typical region and the explanation of the muon anomalous magnetic dipole moment (muon g-2) within its 1σ error. In particular, the explanation of the muon g-2 anomaly has been considered to be difficult in this model due to the heavy stop masses required by the measured SM Higgs boson mass and the condition of the universal sfermion mass at the GUT scale. [arXiv:1606.04953]
I will propose an analyzing method for supersymmetric standard models with some amount of fine tuning. Applying this method to a non-universal Higgs masses model, I will show a new typical region and the explanation of the muon anomalous magnetic dipole moment (muon g-2) within its 1σ error. In particular, the explanation of the muon g-2 anomaly has been considered to be difficult in this model due to the heavy stop masses required by the measured SM Higgs boson mass and the condition of the universal sfermion mass at the GUT scale. [arXiv:1606.04953]
I will also propose a new simple set up of the MSSM, where at the GUT scale, only the Higgs sector is coupled with SUSY breaking. All the other sparticles obtain masses from the Higgs sector via RG running and superWeyl anomaly. The sfermion spectra are typical where the first two generation sfermions are as light as ~1TeV with anomaly induced gaugino masses, while the third ones, Higgsino and A-Higgs are heavier than O(10)TeV. I will discuss about the phenomenology of this set up, such as the explanation of the muon g-2 anomaly, the alleviation of gravitino/flavor problem and also other interesting possibilities.
Taro Kimura, Keio University
Boundary condition analysis of topological insulators
Meeting room 1, Kenkyu honkan 1F, slides (kek.jp only)
Study of topological insulators and superconductors (topological phases of matter) is currently an active research area in condensed-matter physics. One of the most important aspects of them is the renowned relation between bulk and edge states, called the bulk/edge correspondence. The edge state, localized at the material boundary, is sensitive to a boundary condition definitely, but how the boundary condition affects the edge state has not been studied in a systematic way so far. We tackle this problem with a minimal model of topological insulator, and show boundary condition dependence of the edge state, in particular, its energy spectrum and wavefunction behavior. We also argue how such a generic boundary condition is realized in lattice models. This talk is based on a collaboration with K. Hashimoto and X. Wu (Osaka): [arXiv:1509.04676], [arXiv:1602.05577] and work in progress.
Masazumi Honda, Weizmann Institute
How to resume perturbative series in supersymmetric gauge theories
Meeting room 1, kenkyu honkan 1F, slides (kek.jp only) Perturbative series in quanum field theory is typically divergent.
