セミナー

Tomohiro Abe, TsingHua University

LHC Higgs Signatures from Extended Electroweak Gauge Symmetry

Meeting Room 1, Kenkyu Honkan 1F
We study LHC Higgs signatures from the extended electroweak gauge symmetry SU(2) x SU(2) x U(1). Under this gauge structure, there are two neutral Higgs states (h, H) and three new gauge bosons (W’, Z’). We identify the lighter Higgs state h with mass 125GeV. The parameter space of this model is highly predictive. We study the production and decay signals of this 125GeV Higgs boson h at the LHC. We demonstrate that the h can naturally have enhanced signals in the diphoton channel gg→h→γγ, while the events rates in the reactions gg→h→WW* and gg→h→ZZ* can be same as the SM expectation.

Tastu Takeuchi, Virginia Tech

Some Mutant Forms of Quantum Mechanics

Seminar Room, Kenkyu Honkan3F
In order to progress our understanding of Quantum Mechanics, we advocate what we call the “geneticist’s approach” in which we introduce mutations to the mathematical genotypes of Quantum Mechanics and study how it affects the physical phenotypes of the theory. We show a few examples of such “mutations” and how the predictions of Quantum Mechanics are affected. We argue that in the process, the physical meanings of various mathematical aspects of Quantum Mechanics will be clarified, and further possible directions of evolution will be evinced.

Hiroyuki Abe, Waseda Univ.

Phenomenological aspects of ten-dimensional super Yang-Mills theory on magnetized tori

Meeting Room 3, Kenkyu Honkan 1F
We present a particle physics model based on a ten-dimensional super Yang-Mills theory compactified on magnetized tori preserving four-dimensional N=1 supersymmetry.
The low-energy spectrum contains the minimal supersymmetric standard model with hierarchical Yukawa couplings caused by a wavefunction localization of the chiral matter fields due to the existence of magnetic fluxes, allowing a semi-realistic pattern of the quark and the lepton masses and mixings.
We show supersymmetric flavor structures at low energies induced by a moduli-mediated and an anomaly-mediated supersymmetry breaking.

Mark Vagins, Kavli IPMU, U. of Tokyo

GADZOOKS! How to See Extragalactic Neutrinos By 2016

Meeting Room 1, Kenkyu Honkan 1F 
Water Cherenkov detectors have been used for many years to study neutrino interactions and search for nucleon decays. Super-Kamiokande, at 50 kilotons the largest such underground detector in the world, has enjoyed over fifteen years of interesting and important physics results. Looking to the future, for the last nine years R&D on a potential upgrade to the detector has been underway. Enriching Super-K with 100,000 kilograms of a water-soluble gadolinium compound – thereby enabling it to detect thermal neutrons and dramatically improving its performance as a detector for supernova neutrinos, reactor neutrinos, atmospheric neutrinos, and also as a target for the T2K long-baseline neutrino experiment – will be discussed.

Gaber Faisel, National Central U

Supersymmetric contributions to B_s --> φ π^0 and B_s --> φ ρ^0 decays in SCET

Meeting Room 1, Kenkyu Honkan 1F
In this talk I present the study of the decay modes B_s –> φ π^0 and B_s –> φ ρ^0 using Soft Collinear Effective Theory. I briefly give an introduction to Soft Collinear Effective Theory and discuss the importance of electroweak penguins in the decay modes B_s –> φ π^0 and B_s –> φ ρ^0. The branching ratios of these decay modes are so small in the SM and thus provide a test for new physics beyond SM.

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.

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