Biswarup Mukhopadhyaya, Harish-Chandra Research Institute, Allahabad, India
The credibility of SUSY phenomenology: some silver linings
Meeting room 3, Kenkyu Honkan 1F
With mass limits on supersymmetric particles going up, the role of supersymmetry (SUSY) as the prime option for physics beyond the standard model may appear somewhat debatable to some quarters. In this backdrop, we start by briefly touching upon the desirability as well viability of SUSY in the current context. Then we summarise a few recent works, particularly those by our group, where there is a slight departure from the commonest approaches to SUSY phenomenology, be it in logic, motivation or collider signals.
Yukinari Sumino, Tohoku University
Understanding Heavy QuarkAntiQuark System by Perturbative QCD
Meeting room 1, Kenkyu honkan 1F
Due to the discovery of renormalon cancellation, it became possible to describe the nature of a heavy quarkantiquark system (such as bottomonium) based on perturbative QCD, both qualitatively and quantitatively. Accordingly, interpretaions of the heavy quark mass and interquark force have been modified considerably. I overview what has been understood and some of theoretical progress since then. The UV part of the interquark potential can be computed in perturbative QCD. We show that a “Coulomb+linear” potential is obtained as the prediction.
Ryusuke Jinno, The University of Tokyo
Gravitational effects on inflaton decay
Meeting room 1, Kenkyu honkan 1F The inflaton inevitably couples to all non-conformally coupled matters to gravity, through an oscillation in the Hubble parameter or the cosmic scale factor. This oscillation leads to particle production during the inflaton oscillation regime. In this talk, I first apply the analysis of scalar particle production to the case of minimally-coupled inflaton to gravity, and then extend the analysis to non-minimally coupled case, in which the Hubble parameter oscillates more violently. I also show the analysis of the graviton production by the inflaton in both minimal & non-minimal case.
The inflaton inevitably couples to all non-conformally coupled matters to gravity, through an oscillation in the Hubble parameter or the cosmic scale factor. This oscillation leads to particle production during the inflaton oscillation regime. In this talk, I first apply the analysis of scalar particle production to the case of minimally-coupled inflaton to gravity, and then extend the analysis to non-minimally coupled case, in which the Hubble parameter oscillates more violently. I also show the analysis of the graviton production by the inflaton in both minimal & non-minimal case.
Reference :
1. Gravitational Effects on Inflaton Decay, Yohei Ema, Ryusuke Jinno, Kyohei Mukaida, Kazunori Nakayama arXiv:1502:02475
2. Yohei Ema, Ryusuke Jinno, Kyohei Mukaida, Kazunori Nakayama, to appear
Vojtech Krejcirik, RIKEN
[cancelled] Few new insights into $\bar{K}N$ interaction
Seminar room, Kenkyu honkan 3F
In this talk, I will report on the recent progress in the analysis of meson-baryon interaction in the strange sector. In the first part, the EFT motivated model taking into account both L=0 and L=1 partial wave will be presented. The model aims at a uniform treatment of both $\Lambda(1405)$ and $\Sigma(1385)$ resonances both in vacuum and in the nuclear medium. The second half of the talk will be devoted to the discussion of lattice QCD approach (HAL QCD approach, in particular) to the problem.
鈴木惇也, 東京大学
[Cosmophysics seminar] Hidden Photon ダークマター探索
Room 345, 4 go-kan 3F
ダークマターの存在はさまざまな観測結果から示唆されており、その直接探索実験は実験物理学の花形の一つとなっている。現在、ダークマターの正体として WIMP を想定し原子核反跳を捉える実験が盛んにおこなわれている。一方、それ以外に axion などの軽い粒子が非熱的に生成されるというシナリオも考えられ、その探索を目指す実験として ADMX などがある。近年、hidden photon (dark photon) も非熱的なシナリオでダークマターになりうることが指摘され、その新奇な探索手法として dish antenna を用いた方法が 提案された。それを受けて我々の研究室では、 ~ eV と ~10^{-5} eV 、２つの hidden photon 質量領域をカバーする２つの実験装置をつくり、その探索を行った。本講演ではダークマターの可能性としての hidden photon について、その実験手法と我々の探索結果についての話をおこなう。
Daisuke Harada, KEK
Phenomenology of Heavy vector-like quarks
Meeting room 1, Kenkyu honkan 1F
Ｋ中間子の崩壊におけるCPの破れについて説明するため、クォークの世代数が、少なくとも３世代以上であることが知られている。標準模型の枠内では、４世代目のクォークおよびレプトンが存在してはいけないという理論的な理由は存在しない。しかしながら、最近のＬＨＣ実験におけるヒッグス探索の結果によって、４世代目のカイラルなクォークは強く否定されている。この実験によって、４世代目のクォーク自体が否定されているわけではなく、その他の可能性として、ベクターライクフェルミオンが知られている。例えば、リトルヒッグス模型や余剰次元の模型といった様々なNew Physicsの模型において、このようなフェルミオンが導入されている。従って、このようなベクターライクフェルミオンがTeVスケールの物理の与える影響について調べることは非常に興味深い。我々の研究では、個々の模型に依存せずにベクターライクフェルミオンの効果について調べるため、有効模型を用いて、LHC実験における発見可能性やフレーバー物理に与える影響について調査した。セミナーでは、この研究成果について議論する。
Yuichiro Nakai, Harvard University
Deconstruction, Holography and Emergent Supersymmetry
Meeting room 1, Kenkyu honkan 1F In this talk, we discuss a gauge theory in a 5D warped space via the dimensional deconstruction that a higher dimensional gauge theory is constructed from a moose of 4D gauge groups. By the AdS/CFT
In this talk, we discuss a gauge theory in a 5D warped space via the dimensional deconstruction that a higher dimensional gauge theory is constructed from a moose of 4D gauge groups. By the AdS/CFT
correspondence, a 5D warped gauge theory is dual to a 4D conformal field theory (CFT) with a global symmetry. As far as physics of the gauge theory, we obtain the one-to-one correspondence between each component of a moose of gauge groups and that of a CFT. We formulate a supersymmetric extension
of deconstruction and explore the framework of natural supersymmetry in a 5D warped space – the supersymmetric Randall-Sundrum model with the IR-brane localized Higgs and bulk fermions – via the gauge moose. In this model, a supersymmetry breaking source is located at the end of the moose corresponding to the UV brane and the first two generations of squarks are decoupled. With left-right gauge symmetries in the bulk of the moose, we demonstrate realization of accidental or emergent supersymmetry of the Higgs sector in comparison with the proposed “Moose/CFT correspondence.”
Kohsaku Tobioka, Tel Aviv U., Weizmann, KEK
Probing Higgs-charm coupling, for current and future LHC
Meeting room 1, Kenkyu honkan 1F
We introduce four different types of datadriven analyses that constrain the size of the Higgscharm Yukawa coupling: (i) recasting the vectorboson associated, Vh, analyses that search for bottompair final state; (ii) the direct measurement of the total width; (iii) the search to h> J/\psi\gamma; (iv) a global fit to the Higgs signal strengths. A comparison with t\bar{t}h data allows us to show that the Higgs does not couple to quarks in a universal way. Finally, we demonstrate how the experimental collaborations can further improve our direct bound (i) using charmtagging.
Khaiming Wong, Universiti Sains Malyasia
Monopole-Antimonopole System and Vortex-ring Configurations in the Weinberg-Salam Model
Seminar room, Kenkyu honkan 3F The Georgi-Glashow model is famous for the huge families of magnetic monopole solutions, the most important of all solution is the well-known ‘t Hooft-Polyakov monopole. For the more realistic Weinberg Salam model, Nambu has demonstrated the existence of a rotating dumb-bell made of monopole and antimonopoly, connected by a flux string of neutral field.
The Georgi-Glashow model is famous for the huge families of magnetic monopole solutions, the most important of all solution is the well-known ‘t Hooft-Polyakov monopole. For the more realistic Weinberg Salam model, Nambu has demonstrated the existence of a rotating dumb-bell made of monopole and antimonopoly, connected by a flux string of neutral field.
Some years later, Cho and Maison showed the Georgi-Glashow and Weinberg-Salam model possesses exactly the same topological structure, and constructed a spherically symmetric Weinberg-Salam monopole, namely the Cho-Maison monopole. In this work we solve the Weinberg-Salam equations of motion for numerical solutions which are generalization of Nambu’s electroweak monopole and the Cho-Maison monopole. These solutions correspond to series of magnetic poles with alternating sign aligned along the z-axis, which include the monopole-antimonopole chain, monopole-antimonoploe pair, and vortex ring.
Tao Liu, The Hong Kong University of Science and Technology
New Strategies on Higgs measure measurements at pp colliders: from LHC to a 100 TeV machine
Meeting room 1, Kenkyu honkan 1F
