Yuta Hamada, Kyoto University
Bare Higgs mass at Planck scale
Meeting Room 1, Kenkyu Honkan 1F
We compute one and two loop quadratic divergent contributions to the bare Higgs mass in terms of the bare couplings in the Standard Model (SM). We approximate the bare couplings, defined at the ultraviolet cutoff scale, by the MSbar ones at the same scale, which are evaluated by the two loop renormalization group equations for the Higgs mass around 126GeV in the SM. We obtain the cutoff scale dependence of the bare Higgs mass, and examine where it becomes zero. We find that when we take the current central value for the top quark pole mass, 173GeV, the bare Higgs mass vanishes if the cutoff is about 10^{23}GeV. With a 1.3 sigma smaller mass, 170GeV, the scale can be of the order of the Planck scale.
Taichi Kawanai, KMI Nagoya
Heavy quarkonium potential from lattice QCD (in Japanese)
Seminar Room, Kenkyu Honkan 3F
We study properties of an interquark potential for the charmed meson systems in lattice QCD. In this study, we propose a new method to determine the interquark potentials together with quark kinetic mass from the equal time QQbar Bethe-Salpteter (BS) amplitude through the effective Schroedinger equation. The study of the interquark potentials at finite quark masses from lattice QCD provides an new way to explore properties of heavy quarkonium states where very rich mass spectrum have been recently exposed in experiments.
Satoshi Ohya, Harish-Chandra Research Institute
Path integral junctions
Seminar room, Kenkyu honkan 3F
I propose a new path integral formulation of one-particle quantum mechanics on equilateral quantum wire junctions. I find that scale-invariant junctions realized at fixed points of boundary renormalization group flow are in one-to-one correspondence with matrix-valued weight factors on the path integral side. I show that these weight factors are generally given by multi-dimensional unitary representations of the infinite dihedral group.
Satyanarayan Mukhopadhyay
Effective couplings of the Higgs boson in the light of recent LHC and Tevatron data
Meeting Room 1, Honkan Building 1F
How much can the effective couplings of the Higgs boson deviate from their standard model predictions? We perform a multi-parameter global analysis of the recent LHC and Tevatron data and try to address this question in a very general and model independent setting
Yukinao Akamatsu, KMI, Nagoya
In-medium QCD forces at high temperature
Meeting Room 1, Kenkyu Honkan 1F
The physics of heavy quarkonium suppression in quark-gluon plasma has been discussed in the context of screened QCD force in medium for a long time. In this talk, I will show that another type of force, namely the drag force and its fluctuation, also plays an important role in the real-time dynamics of heavy quarkonium in the medium. In order to make this statement concrete, I will employ the closed-time path formalism of non-equilibrium quantum field theory and perform leading order perturbative analysis. This will tell us how these different types of forces determine the dynamics of quantum states of heavy quark systems in the medium.
Zoltan Fodor, University of Wuppertal, Eotvos University
QCD thermodynamics on the lattice
Meeting Room 1, Kenkyu Honkan 1F
Recent result of lattice QCD thermodynamics are summarized. The nature of the transition between low and high temperatures is determined. Its characteristic temperature (T_c) is calculated. The equation of state is given. Selected results at nonvanishing chemical potentials are presented. Special emphasis is put on the physical point (physical quark masses and extrapolation to the continuum limit).
Makoto Sasaki, The University of Tokyo, ICRR
Ashra NTA
Meeting Room 1, Kenkyu Honkan 1F The Earth-skimming tau neutrino technique detects extensive air showers produced by tau lepton decays in the atmosphere, which enjoys a large target mass. The tau leptons, produced by VHE tau neutrinos that interact with the Earth matter they traverse, emerge out of a mountain or the ground facing the detector. This method has detection sensitivity in the PeV-EeV region, and can be used to search for neutrinos originating from hadron acceleration in astronomical objects. Additional advantages are perfect shielding of cosmic ray secondaries, precision arrival direction determination, and negligible background from atmospheric neutrinos. The All-Sky High Resolution Air-shower detector (Ashra) projects were independently developed to detect tau neutrinos with the Earth-skimming method. Aiming for realizing very high energy “multi-particle astronomy”, the Ashra detector has been developed since 2002 with 1 arcmin pixel resolution and all-sky coverage. The principal demonstration phase, Ashra-1, has been running at the Mauna Loa site at 3300m above sea level on Hawaii Island since 2008. Ashra-1 succeeded in the first search for PeV-EeV tau neutrinos originating from a GRB as the commissioning run, and has achieved best instantaneous sensitivity since January 2012 after trigger upgrade.
The Earth-skimming tau neutrino technique detects extensive air showers produced by tau lepton decays in the atmosphere, which enjoys a large target mass. The tau leptons, produced by VHE tau neutrinos that interact with the Earth matter they traverse, emerge out of a mountain or the ground facing the detector. This method has detection sensitivity in the PeV-EeV region, and can be used to search for neutrinos originating from hadron acceleration in astronomical objects. Additional advantages are perfect shielding of cosmic ray secondaries, precision arrival direction determination, and negligible background from atmospheric neutrinos. The All-Sky High Resolution Air-shower detector (Ashra) projects were independently developed to detect tau neutrinos with the Earth-skimming method. Aiming for realizing very high energy “multi-particle astronomy”, the Ashra detector has been developed since 2002 with 1 arcmin pixel resolution and all-sky coverage. The principal demonstration phase, Ashra-1, has been running at the Mauna Loa site at 3300m above sea level on Hawaii Island since 2008. Ashra-1 succeeded in the first search for PeV-EeV tau neutrinos originating from a GRB as the commissioning run, and has achieved best instantaneous sensitivity since January 2012 after trigger upgrade.
Based on these achievements, we start to form a new collaboration for concrete design and planning for the next generation large Neutrino Telescope Array (NTA). The conceptual layout for the NTA observatory considers three site stations for a 25km-grid triangle watching the total air mass surrounded by the mountains of Mauna Loa, Mauna Kea, and Hualalai. A single site station at the center of the triangle has full-sky coverage. This configuration allows tremendous sensitivity (equivalent to > 100 giga ton water) with Cherenkov-fluorescence stereoscopic observation for PeV-EeV neutrinos in essentially background-free conditions. With the demonstrated fine imaging of Earth-skimming tau showers, we aim for clear discovery and identification of astronomical tau neutrino sources. I would introduce our detector performance, potential capabilities of physics probes into main physics of Very-high energy neutrino search and some of various bread and butter physics like determination of cosmic ray composition with direct cherenkov method and so on.
Tadashi Takayanagi (YITP, Kyoto U / Kavli IPMU, U Tokyo)
Holographic Entanglement Entropy and Emergent Spacetime
Meeting Room 1, Kenkyu Honkan 1F
After a brief review of (holographic) entanglement entropy, we will first introduce our latest result on a thermodynamical property of entanglement entropy for excited states. Later, we study a conjectured connection between the AdS/CFT and a real-space quantum renormalization group scheme, the multi-scale entanglement renormalization ansatz (MERA). By making a close contact with the holographic formula of the entanglement entropy, we propose a general definition of the metric in the MERA in the extra holographic direction, which is formulated purely in terms of quantum field theoretical data.
堀内渉, 北海道大学大学院理学研究院
[Particle and Nuclear Physics Seminar at J-PARC] 第一原理計算による4Heの電弱励起の研究
Tokai 1st building 115, KEK Tokai campus
本講演では4Heの電弱応答について、４体計算による解析結果を紹介する。低励起の光吸収断面積は基底状態から非束縛な励起状態への電気双極子遷移による。あらわに相関した特殊な波動関数を用いることにより、核力によって強く相関する４核子系を一つの枠組みで記述した。得られた光吸収断面積は実験値を広いエネルギー領域でよく再現し、反応閾値近傍の光吸収断面積では3He+n, 3H+pクラスター配位が重要となること、光吸収断面積の総和に対応するThomas-Reiche-Kuhn和則へはπ中間子交換力、とりわけテンソル力が主要な寄与を成すことを示した。また、電気双極子演算子に類似のスピン双極子演算子による遷移はニュートリノー原子核反応の際に重要となる。得られたスピン双極子強度関数は実験のスペクトル、共鳴パラメータをよく再現し、和則においてテンソル力の効果を示唆する結果が得られた。
杉本茂樹, カブリ数物連携宇宙機構
超対称性のないゲージ理論における S-duality とカラーの閉じ込め
Meeting Room 1, Kenkyu Honkan 1F
