Seminar Information (2017)

Particle Theory Group of Tokyo Metropolitan University


December 13rd (Wed.), at 14:40 @8-308

" Dynamical scalegenesis via bosonic seesaw mechanism "

Dr. Shinya Matsuzaki (Nagoya University)

We propose a model which accounts for the dynamical origin of the electroweak symmetry breaking, directly linking to the mass generation of dark matter candidate and active neutrinos. This dynamical scale generation is triggered by a couple of seesaw mechanisms (bosonic seesaws) induced from a newly introduced vectorlike confinement sector (hypercolor). Phenomenological consequences (including dark matter physic and LHC signals) derived from this scenario are discussed.

November 29th (Wed.), at 14:40 @8-308

" Belle II experiment "

Dr. Hidekazu Kakuno (Tokyo Metropolitan University)

November 22nd (Wed.), at 14:40 @8-308

" Neutrino physics in the minimal gauged U(1) L_mu - L_tau model "

Dr. Natsumi Nagata (University of Tokyo)

In the minimal gauged U(1)_{L_mu - L_tau} model, the neutrino mass structure is tightly restricted because of the gauge symmetry. In particular, it is found that for the observed values of the neutrino squared mass differences and the mixing angles, all of the CP phases in the neutrino mass matrix as well as the light neutrino mass eigenvalues are fully determined with great accuracy. I will discuss this prediction and the prospects for testing it in the future neutrino experiments. I will also show the implication for leptogenesis in this minimal setup.

October 18th (Wed.), at 14:40 @8-308

" An approach to the instanton effect in B system "

Mr. Yuki Sakai (Tokyo Metropolitan University)

July 5th (Wed.), at 14:40 @8-300

" Tensions in neutrino oscillation experiments and nonstandard interactions "

Dr. Osamu Yasuda (Tokyo Metropolitan University)

flavor neutrino mixing, there have been a couple of anomalies, which may imply the deviation from the standard neutrino oscillation scenario. (i) a non-zero best-fit value of the non-standard oscillation parameters in the the global analysis of the solar and KamLAND data which rules out the standard oscillation scenario at 90% C.L, (ii) the measurement of the non-maximal value of theta_{23} by nova which excludes the maximal mixing at 2.5 sigma C.L. In this talk, I will discuss the possibility to explain these anomalies by introducing the flavor dependent nonstandard interactions of neutrinos. Also I will briefly discuss other possibility to explain the non-maximal mixing of the nova data by introducing larger systematic errors in the neutrino energy.

June 28th (Wed.), at 14:40 @8-300

" Quartic gauge boson couplings and the Electroweak Skyrmion "

Dr. Toshifumi Kurachi (KEK)

Topological objects play important roles in various areas of physics, and the physics of the dark matter might be no exception. In this talk, I will discuss the existence of a dark matter candidate in the Higgs sector of the Standard Model with a minimal addition of higher derivative operators. The talk is based on JHEP 1607 037 (2016) [arXiv:1605.07355] and JHEP 1704 150 (2017) [arXiv:1703.06397].

June 14th (Wed.), at 14:40 @8-300

" Prospects of the T2HKK experiment "

Dr. Monojit Ghosh (Tokyo Metropolitan University)

T2HKK is the proposed long-baseline experiment to determine the unknown neutrino oscillation parameters in standard three flavour framework i.e., (i) the mass ordering of the neutrinos and (ii) the information of the leptonic CP phase. The unique two detector setup of this experiment will be helpful to determine both these quantities with high precision. In this talk I will discuss the configuration of T2HKK experiment and its physics capabilities in both standard and non-standard scenarios.

May 31th (Wed.), at 14:40 @8-300

" Quantum Entanglement and Emergent Geometry "

Dr. Kento Watanabe (YITP)

The gauge/gravity correspondence developed in string theory gives us an interesting insight. It links quantum entanglement and gravitational spacetime. Using measures of quantum information, for example entanglement entropy, we can probe emergent geometries encoded in quantum states. Moreover, tensor networks, which efficiently describes quantum states with proper quantum entanglement, suggest the emergent geometries. In this seminar, I would like to review some developments in this context and our recent works.

May 17th (Wed.), at 14:40 @8-300

" A Model of Black Hole Evaporation and 4D Weyl Anomaly "

Dr. Yuki Yokokura (RIKEN)

We analyze time evolution of a spherically-symmetric collapsing matter from a point of view that black holes evaporate by nature. We consider conformal matters and solve the semi-classical Einstein equation by using the 4-dimensional Weyl anomaly with a large c coefficient. Here the energy-momentum tensor contains the contribution from both the collapsing matter and Hawking radiation. The solution indicates that the collapsing matter forms a dense object and evaporates without horizon or singularity, and it has a surface but looks like an ordinary black hole from the outside. Any object we recognize as a black hole should be such an object. [arXiv: 1701.03455]

April 26th (Wed.), at 14:40 @8-300

" Probing Pre-inflationary Physics From Cosmic Microwave Background "

Dr. Noriaki Kitazawa (Tokyo Metropolitan University)

The possible physics of the beginning of inflation will be discussed by taking a model in string theory as an example. The physics gives some imprints in primordial scalar perturbations which were created through the accelerated expansion of the Universe during inflation. One of the typical imprint is the dumping of the amplitude or power of the Cosmic Microwave Background (CMB) at long wave lengths. Next we will discuss whether such an imprint has been observed by PLANC and WMAP experiments. The observational data show the dumping of the power of the CMB at long wave lengths about 3-sigma level with larger galactic mask than the standard one. The observational data also show that we have to take larger galactic mask because of some unknown contaminations in the region closer to the galactic surface.

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