Back Numbers 2015-16
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  • April 10, 2015
       Cosmological Collider Physics
        K. Suehiro (Hokkaido Univ.)
  •  E-PRINT : Nima Arkani-Hamed, Juan Maldacena, " Cosmological Collider Physics " arXiv:1503.08043[hep-th]

     COMMENT : Journal Club

  • April 17, 2015
      Non-supersymmetric heterotic model building
        Y. Takano (Hokkaido Univ.)
  •  E-PRINT : Michael Blaszczyk, Stefan Groot Nibbelink, Orestis Loukas, Saul Ramos-Sanchez,
            " Non-supersymmetric heterotic model building " arXiv:arXiv:1407.6362

     COMMENT : Journal Club

  • April 24, 2015
        T. Houri (kobe Univ.)
  •   Liouville integrability of Hamiltonian systems and spacetime symmetry
      ABSTRACT : Hamiltonian dynamical systems are said to be integrable in the Liouville sense if there exists a
              maximal set of first integrals that are Poisson commuting with each other. However, it is not always
              easy to find such a set of first integrals for a given system. In this talk, I will show that any natural
              Hamiltonian dynamics can be rephrased as geodesic problem in a curved spacetime, where the
              existence of first integrals in the original Hamiltonian system corresponds to the existence of
              symmetry of the corresponding spacetime, and discuss on a technique for finding spacetime symmetry.

      COMMENT : Seminar (Morning Session)

      Killing-Yano symmetry and supergravity black holes
      ABSTRACT : Killing-Yano symmetry has been thought of as hidden symmetry of spacetimes because thanks to
              such symmetry equations of motion for test particles and test scalar and Dirac fields -
              - Hamilton-Jacobi, Klein-Gordon and Dirac equations -- can be solved by separation of variables.
              The most remarkable property of spacetimes admitting Killing-Yano symmetry is that when the
              vacuum Einstein equation is assumed, metrics on such spacetimes are determined to be black
              hole solutions. In this talk, I will discuss on black hole solutions admitting Killing-Yano symmetry
              in the context of supergravity theory.

      COMMENT : Seminar (Afternoon Session)


  • May 1, 2015
      Towards a Non-Supersymmetric String Phenomenology
        H. Suzuki (Hokkaido Univ.)
  •  E-PRINT : Steven Abel, Keith R. Dienes, Eirini Mavroudi, " Towards a Non-Supersymmetric String Phenomenology "

     COMMENT : Journal Club

  • May 8, 2015
      Oscillations of the \(^7\)Be solar neutrinos inside the Earth
        Y. Tobita (Hokkaido Univ.)
  •  E-PRINT : A. N. Ioannisian, A. Yu. Smirnov, D. Wyler, " Oscillations of the \(^7\)Be solar neutrinos inside the Earth "

     COMMENT : Journal Club

  • May 15, 2015
        S. Sugishita (Kyoto Univ.)
      Ramond-Ramond couplings of D-branes
  •   ABSTRACT : We find the general Ramond-Ramond coupling formula including open string massive modes on
              D9-branes in the context of the boundary string field theory (BSFT). For superstring theory,
              the BSFT action of open string is given by a disk worldsheet partiton function with boundary
              interactions corresponding to open string excitations. Applying the supersymmetric localization
              technique to superstring worldsheet theory with arbitrary worldsheet-supersymmetric boundary
              interactions, we find that a finite number of massive modes can contriute to Ramond-Ramond
              coupling formula and that the formula is written in terms of Quillen's superconnection including
              higher form fields. We also find that any D9-branes creation via condensation of massive modes
              never happens.
      E-PRINT : JHEP 1503 (2015) 077 arXiv:1501.00095[hep-th]

      COMMENT : Seminar

  • May 22, 2015
        Y. Sato (Kyoto Univ.)
      Comments on Entanglement Entropy in the dS/CFT Correspondence
  •   ABSTRACT : We consider the entanglement entropy in the dS/CFT correspondence. In Einstein gravity on
              de Sitter spacetime we propose the holographic entanglement entropy as the analytic continuation
              of the extremal surface in Euclidean anti-de Sitter spacetime. Even though dual conformal field
              theories for Einstein gravity on de Sitter spacetime have not been known yet, we analyzed the
              free Sp(N) model dual to Vasiliev's higher spin gauge theory as a toy model. In this model we
              confirmed the behaviour similar to our holographic result from Einstein gravity.
      E-PRINT : Phys.Rev. D91 (2015) 8, 086009 arXiv:1501.04903 [hep-th]

      COMMENT : Seminar

  • May 29, 2015
        K. Hotta (Hokkaido Univ.)
      Closed Superstrings at Finite Temperature in the Framework of Thermo Field Dynamics
  •   ABSTRACT : Although the finite temperature systems of strings have been mainly examined in the framework
              of Matsubara formalism, quite a few works have been done to investigate these systems in the
              framework of thermo field dynamics. Previously we have calculated the thermal vacuum state
              and the partition function for a single closed superstring in the framework of thermo field dynamics.
              From this we can reproduce the free energy for multiple strings in the case of Matsubara method.
              However it is unsatisfactory to derive free energy in such a way, since the free energy for multiple
              strings should be obtained by only calculating the expectation value of the corresponding operator
              in the thermal vacuum state. In this talk, we compute the thermal vacuum state for multiple closed
              superstrings based on free light-cone superstring field theory. From this we can reproduce the
              free energy for closed superstrings in the case of Matsubara method. We comment on the relation
              between this closed superstrings at finite temperature and the open superstrings on D9-brane-
              -anti-D9-brane pairs.

      COMMENT : Seminar


  • June 5, 2015
        M. Kakizaki (Toyama Univ.)
      Dark matter in universal extra dimension models
  •   Abstract : Models where all the Standard Model particle propagate in extra dimensions, so-called universal
             extra dimension models, can be accompanied by symmetry related to their geometry. Due to the
             symmetry, the lightest first Kaluza-Klein (KK) particle that is a partner of one of the neutral
             standard model particles, mostly that of the hypercharge gauge boson is stabilized and thus an
             excellent candidate for dark matter. As a consequence, the first KK mode of hypercharge gauge
             boson can be a weakly interacting massive particle (WIMP) whose thermal relic abundance
             satisfies the observed dark matter abundance. In this talk, we focus this case and show that
             various first and second KK particles affect the amount of this WIMP candidate drastically. We
             also discuss experimental signatures of such models at direct and indirect dark matter detections
             as well as at on-going and future colliders.
      References : G.Belanger, A.Belyaev, M.Brown, M.Kakizaki and A.Pukhov,
                  Phys. Rev. D 87, no. 1, 016008 (2013)  arXiv: 1207.0798[hep-ph]
               G.Belanger, M.Kakizaki and A.Pukhov, JCAP 1102, 009 (2011)  arXiv: 1012.2577[hep-ph]
               M.Kakizaki, S.Matsumoto and M.Senami, Phys. Rev. D 74, 023504 (2006)  arXiv: hep-ph/0605280
               M.Kakizaki, S.Matsumoto, Y.Sato and M.Senami, Nucl. Phys. B 735, 84 (2006)  arXiv: hep-ph/0508283
               M.Kakizaki, S.Matsumoto, Y.Sato and M.Senami, Phys. Rev. D 71, 123522 (2005)  arXiv: hep-ph/0502059

      Comment : Seminar

  • June 12, 2015
        S. Kashiwase (Kanazawa Univ.)
      Baryon Asymmetry and Inflation in a Radiative Seesaw Model
  •   Abstract : The standard model has serious problems from experimental and observational standpoints
             neutrino masses, dark matter and baryon asymmetry of the Universe. A radiative seesaw model is
             known as a candidate which could explain neutrino masses and existence of dark matter
             simultaneously. In addition, in this model, the sufficient baryon number asymmetry could be
             generated through resonant leptogenesis at TeV scale. We estimate the baryon number asymmetry
             and discuss the prospects in the dark matter direct search experiments. In addition to three
             problems, inflation should also be explained since the recent CMB observations suggest the
             existence of the inflationary era at the early stage of the Universe. Thus, we extend it by a
             complex scalar field with specific potential. We show that the inflation favored by the CMB
             observations could be realized even if inflaton takes sub-Plankian values during inflation.

      Comment : Seminar

  • June 19, 2015
       Resolving Witten's Superstring Field Theory
        W. Akutsu (Hokkaido Univ.)
  •   E-PRINT : T. Erler, S. Konopka, I. Sachs, "Resolving Witten's Superstring Field Theory" arXiv:1312.2948 [hep-th]

      Comment : Journal Club

  • June 26, 2015
        A. Sako (Tokyo university of science)
       Introduction to Noncommutative geometry
  •     Comment : Seminar (Morning Session)

       Noncommutative Gauge Theory on \(\mathbb{C}P^N\)
         Comment : Seminar (Afternoon Session)


  • July 3, 2015
      Effects of thermal inflation on small scale density perturbation
        H. Hattori (Hokkaido Univ.)
  •  E-PRINT : Sungwook E. Hong, Hyung-Joo Lee, Young Jae Lee, Ewan D. Stewart, Heeseung Zoe,
                      " Effects of thermal inflation on small scale density perturbation " arXiv:1503.08938

     Comment : Journal Club

  • July 10, 2015
        N. Umeda (Kyoto Univ.)
      Random volumes from matrices
  •   Abstract : We propose a new class of models generating three-dimensional random volumes, where each
             configuration consists of triangles glued together along multiple hinges. The models are characterized
             by semisimple associative algebras, and the set of possible diagrams can be reduced by an
             appropriate large N limit such that they represent only (and all of the) tetrahedral decompositions of
             three-dimensional manifolds. We also give a prescription to put local matters on simplices of any
             dimensions (tetrahedra, triangles, edges and vertices). Simple examples include the Ising model
             coupled to three-dimensional quantum gravity. The three-dimensional colored tensor models can be
             obtained by putting specific matters on tetrahedra, triangles and edges at a time.
      References : Masafumi Fukuma, Sotaro Sugishita, Naoya Umeda,
                            "Random volumes from matrices",  arXiv:1503.08812[hep-th]
               Masafumi Fukuma, Sotaro Sugishita, Naoya Umeda,
                            "Putting matters on the triangle-hinge models",  arXiv:1504.03532[hep-th]

      Comment : Seminar

  • July 17, 2015
      Realistic three-generation models from SO(32) heterotic string theory
        T. Tatsuishi (Hokkaido Univ.)
      E-PRINT : Hiroyuki Abe, Tatsuo Kobayashi, Hajime Otsuka, Yasufumi Takano,
            " Realistic three-generation models from SO(32) heterotic string theory " arXiv:1503.06770 [hep-th]
      Comment : M2 Journal Club (Morning Session)

      Domain wall in the NMSSM
        N. Omoto (Hokkaido Univ.)
      E-PRINT : M. Kawasaki and F. Takahashi,
                 " Late-time entropy production due to the decay of domain wall" arXiv:hep-ph/0410158
             T. Asaka, M. Kawasaki,
                     "Cosmological Moduli Problem and Thermal Inflation Models" arXiv:hep-ph/9905467
      Comment : M2 Journal Club (Afternoon Session)

  • July 24, 2015
        R. Nagai (Nagoya Univ.)
  •   Unitarity, Electroweak Precision Physics, and Higgs couplings
      Abstract :  We discuss perturbative unitarity in the 2 -> 2 scattering amplitudes of the longitudinal massive
             spin-1 particles. It is naively broken down in the high energy limit since the longitudinal
             polarization vector grows as energy.
               One way to cancel the bad behavior in the amplitudes is to impose gauge symmetry and to add
             spin-0 particles (“Higgs” bosons). These Higgs coupling strengths with massive spin-1 particles
             are required to satisfy a set of condition, which is known as “unitarity sum rules[1]”
               We (re)visit the unitarity sum rules in the context of the SU(2)×U(1) gauge theory with
             arbitrary neutral Higgs bosons. Furthermore, we discuss the implication of the unitarity sum
             rules to the electroweak precision tests(EWPTs)[2], which have not been clarified in earlier literature.
               Finally, we investigate the mass of the extra neutral Higgs bosons applying the unitarity sum
             rules. We find the EWPTs gives us a severe constraints on upper bass bound on the second
             lightest neutral Higgs boson.
      Comment : Seminar (Morning Session)

      The ATLAS 2TeV diboson anomalies and Unitarity sum rules
      Abstract :  We investigate W’ interpretations for the ATLAS 2TeV diboson anomalies from the view point
             of the perturbative unitarity in the longitudinal gauge boson scattering amplitudes.
              We derive a set of unitarity sum rules in a class of models with the custodial symmetry including
             arbitrary number of the custodial triplet vector bosons (W,W’,W’’…) and neutral Higgs bosons
             (h,h’,h’’…). We then find the unitarity sum rules give us non-trivial relations among WWZ’,
             WZW’,hWW’, and hZZ’ coupling strengths.
              Applying the unitarity sum rules, we perform surveys in the general parameter space of W’
             models. It is found that the non standard-model-like Higgs boson is favored by the present data
             to interpret the ATLAS diboson anomalies as the consequences of the W’ and Z’ bosons.
      Comment : Seminar (Afternoon Session)

      E-PRINT : [1] J.F.Gunion, H.E.Haber, and J.Wudka Phys.Rev. D43 (1991) 904-912 "Sum rules for Higgs bosons"
             [2] R.Nagai, M.Tanabashi, and K.Tsumura Phys.Rev. D91 (2015) 034030 aXiv: 1409.1709
               "Does unitarity imply finiteness of electroweak oblique corrections at one-loop?
                                                 -constraining extra neutral Higgs bosons-"
             [3] R.Nagai, M.Tanabashi, and K.Tsumura Phys.Rev. D91 (2015) 034030 arXiv:1507.01185
                     "Unitarity sum rules, three site moose model, and the ATLAS 2 TeV diboson anomalies"

  • July 31, 2015
      Dark Matter Searches in Supersymmetric Models
        A. Kaneko (Hokkaido Univ.)
      E-PRINT : G. Jungman, M. Kamionkowski, K. Griest,“ Supersymmetric Dark Matter “ arXiv:hep-ph/9506380
      Comment : M2 Journal Club (Morning Session)

      Holographic reprsentation of local operators in de Sitter space
        T. Suzuki (Hokkaido Univ.)
      E-PRINT : X. Xiao,“ Holographic reprsentation of local operators in de Sitter space“ arXiv:1402.7080
      Comment : M2 Journal Club (Afternoon Session)

      Investigation of Gauge-gravity duality via simulations of 2D N=(8,8) super Yang-Mills
        E. Gigu\(\acute{{\mathrm e}}\)re (Hokkaido Univ.)

     COMMENT : Seminar (for sutudents)


  • August 3, 2015
      Soft theorem and consistency relations for the primordial perturbations
        Y. Urakawa (Nagoya Univ.)
      Abstract :  In quantum field theory, it is widely known that a symmetry leads to a corresponding
              Ward-Takahashi (WT) identity. For the primordial perturbations, the WT identity of the scaling
              symmetry gives the consistency elation, which connects the (n+1)-point function of the curvature
              perturbation with one soft xternal leg to the n-point function. We show that the consistency
              relation implies the conservation of the curvature perturbation at large scales in holographic
              inflation and also in two field models with isocurvature loops.
              In the morning session, I'll give a brief review on inflation and (if I have time) also on a holographic
              description of inflationary scenario, which provides an alternative description of inflation.
              Then, in the afternoon session, I'm going to talk about our recent works.
      E-PRINT : Jaume Garriga, Yuko Urakawa (Barcelona U., Dept. Fund. Phys. & ICC, Barcelona U.),
             “ Inflation and deformation of conformal field theory“ arXiv:1303.5997 [hep-th]
      Comment : Informal seminar

  • August 4, 2015
      How one determines alpha_s on the lattice ?
        Rainer Sommer (DESY, Hamburg)
      Comment : Informal seminar

  • August 7, 2015
      Lepton flavour violation in the inverse seesaw and its supersymmetric realization
        C\(\acute{{\mathrm e}}\)dric Weiland (Universidad Aut\(\acute{{\mathrm o}}\)noma de Madrid)
      Abstract :  The discovery of neutrino oscillations more than a decade ago called for an extension of the
              Standard Model that would generate neutrino masses and mixing. We considered a specific
              mechanism, the inverse seesaw, that introduces new fermionic gauge singlets around the TeV
              scale with large couplings to SM leptons. This leads to a rich phenomenology and makes it easily
              testable at current and future experiments. After describing the inverse seesaw and its
              embedding in a supersymmetric framework, we will discuss their predictions for lepton flavour
              violating (LFV) observables in light of the recent CMS excess in the Higgs to tau mu channel and
              future experimental sensitivities to LFV lepton decays.
      Comment : Informal Seminar

  • August 26, 2015
      LHC phenomenology of natural MSSM with non-universal gaugino masses at the unification scale
        J. Kawamura (Waseda Univ.)
      Abstract :  We study collider phenomenology in the supersymmetric Standard Model with a certain type of
              non-universal gaugino masses at the gauge coupling unification scale, motivated by the little
              hierarchy problem. In this scenario, especially the wino mass is relatively large compared to the
              gluino mass at the unification scale, and the heavy wino can relax the fine-tuning of the higgsino
              mass parameter,so-called μ parameter. Besides, it will enhance the lightest Higgs boson mass
              due to the relatively large left-right mixing of top squarks through the renormalization group (RG)
              effect. Then 125GeV Higgs boson could be accomplished, even if the top squarks are lighter than
              1TeV and the μ parameter is within a few hundreds GeV. The right-handed top squark tends to
              be lighter than the other sfermions due to the RG runnings, then we focus on the top squark
              search at the LHC. Since the top squark is almost right-handed and the higgsinos are nearly
              degenerate, 2b + MET channel is the most sensitive to this scenario. We figure out current and
              expected experimental bounds on the lightest top squark mass and model parameters at the
              gauge coupling unification scale.
      E-PRINT : Hiroyuki Abe, Tatsuo Kobayashi, Yuji Omura,
                 “ Relaxed fine-tuning in models with non-universal gaugino masses“ arXiv:hep-ph/0703044
             Hiroyuki Abe, Junichiro Kawamura, Hajime Otsuka,
             “ The Higgs boson mass in a natural MSSM with nonuniversal gaugino masses at the GUT scale“
             Hiroyuki Abe, Junichiro Kawamura, Yuji Omura,
             “ LHC phenomenology of natural MSSM with non-universal gaugino masses at the unification scale“
      Comment : Informal seminar


  • September 1, 2015 
       Particle physics and cosmology in 5D SUGRA
        H. Otsuka (Waseda Univ.)
      Abstract :  We discuss high- and low-scale SUSY breaking scenarios in the five-dimensional supergravity
              model on S^1/Z_2. The extra U(1) symmetries broken by the orbifold projection control the
              flavor structure of soft SUSY-breaking parameters as well as the Yukawa couplings, and a
              scalar component of the one of moduli multiplets, which arise from extra-dimensional
              components of the U(1) vector multiplets, induces the slow-roll inflation. Because of the
              supersymmetric moduli stabilization as well as the moduli inflation, it is found that the correct
              dark matter relic abundance can be realized in both high- and low-scale SUSY breaking scenarios.
               Finally, we embedd the five-dimensional theory into the type IIB string theory on warped throat.
      Comment : Informal Seminar

  • September 8-10, 2015 
        Y. Ookouchi (Kyushu Univ.)
       Introduction to superstring theories I, II
      Comment : Intensive Lecture  (Bldg.3 3−202)

  • September 10, 2015 
       Baryon as Impurity for Phase Transition in String Landscape
      Abstract :  We consider a decay of a false vacuum in flux compactifications of type IIB string theory and
              study a catalytic effect for a hase transition induced by a new type of impurities.
              We concentrate on the large $N$ dual of a D5-brane/anti-D5-brane system which has a rich
              vacuum structure. We show that D3-branes wrapping the 3-cycles can form a dibaryon and make
              a bound state with a monopole. We find that these baryon-like objects can make the lifetime of
              the metastable vacuum shorter.
      Comment : Seminar


  • October 2, 2015
        K. Isikawa (Hokkaido Univ.)
       1. Dirac, von Neumann, Fermi, 他による遷移確率計算方法の問題点
       2. 遷移確率、 P=Gamma T +P^(d)、における補正項P^(d) の特徴、もたらす効果・影響
     Comment : Seminar (morning session)

       3. ニュートリノ・光反応を中心にしたP^(d)のもたらす物理効果
      E-PRINT : K.Ishikawa and Y.Tobita, Prog. Theor. Exp.Phys. 2013,073B02(2013)
             K.Ishikawa and Y.Tobita, Ann of Phys. 344,118(2014)
             K.Ishikawa, T.Tajima, and Y.Tobita, Prog. Theor. Exp.Phys. 2015,013B02(2015)
             K.Ishikawa and Y.Tobita, arXiv :1503.07285[hep-ph] ,in preparation
             K.Ishikawa, T.Sloan, and Y.Tobita, "On SN1987 A neutrino in the Galaxy"
                                    in preparation 石川健三”フェルミの黄金律 ” ノート、他
      Comment : Seminar (afternoon session)

  • October 9, 2015
       Nonplanar operator mixing and negative anomalous dimensions
        Y. Kimura (OIQP)
      E-PRINT : Yusuke Kimura, Ryo Suzuki, arXiv:1503.06210 [hep-th]
      Comment :  This seminar is canceled.

  • October 16, 2015
       Primordial black hole formation from cosmological fluctuations
        T. Harada (Rikkyo Univ.)
      Abstract :  Primordial black holes are black holes which may have formed in the early universe and affected
             the subsequent evolution of the universe through Hawking radiation and as the source of gravitational
             field. To predict the abundance of primordial black hole formation for given cosmological scenarios,
             it is essential to determine the formation threshold for primordial cosmological fluctuations, which
             are naturally described by cosmological long-wavelength solutions. After a brief introcution, I will
             talk the recent analytical and numerical results on the primordial black hole formation.
              This talk is based on our recent work [1, 2].
      E-PRINT : [1] T. Harada, C. M. Yoo, T. Nakama and Y. Koga,
                           Phys. Rev. D 91 (2015)8, 084057 arXiv:1503.03934 [gr-qc]
             [2] T. Harada, C. M. Yoo and K. Kohri,
               Phys. Rev. D 88 (2013) 8, 084051 [Phys. Rev. D 89 (2014) 2, 029903] arXiv:1309.4201 [astro-ph.CO]
      Comment : Seminar

       Introduction to Supersymmetry
        H. Kato (Hokkido Univ.)
      Comment : M1 Journal Club

  • October 23, 2015
       The structure of neutrino Majorana mass and \(\mu\)-term induced
                                      by rigid instatons on Z\(_2\)×Z\(_2'\) toroidal orbifold

        S. Uemura (Kyoto Univ.)
      Abstract :   Dp-brane insatntons are Dp-branes localized at points in 4 dimensional Minkowski space and
              warapping on (p+1)-cycles in 6 dimensinal compact space. D-brane instantons are important
              non-perturbative effects because they can generate perturbatively forbidden interactions in
              D-brane models, for example neutrino Majorana masses, Higgs mu-terms and so on.
                In this seminar, I review intersecting D-brane modelbuilding briefly and talk about D-brane
              instantons. Then, I compute non-perturbative superpotential in toroidal orbifold, especially
              Majorana mass of right-handed neutrino and mu-terms of Higgs on toroidal orbifold.
                I discuss its phenomenological implications for the flavor structure of leptons too.
      Comment : Seminar

  • October 30, 2015
       Introduction to Classical Mirror Symmetry
        M. Jinzenji (Hokkaido Univ.)
      Contents :  1. T-duality of Bosonic Closed String on S\(^1\)
              2. Compactification of Heterotic String Theory and Mirror Symmetry
              3. Mathematical Prediction of Mirror Symmetry
              4. Topics after 1991
      Comment : Journal Club


  • November 6, 2015
  •    TITLE: TBA
        T. Sasaki (Hokkido Univ.)
      Comment : M1 Journal Club  (start at 14:30-)

       Particle cosmological probes on light dark matter
        K. Kadota (CTPU, IBS)
      Abstract :  he constraints on the light (the mass below GeV-scale) dark matter will be discussed. A few
              examples will be presented, including the constrains from the collider, supernovae, Sun and the
              large scale structure (21cm), to illustrate the complementarity between the particle physics and
              cosmology probes.
      E-PRINT :  KK and Joe Silk, Phys. Rev. D89 (2014) 103528
              Hiroyuki Tashiro, Kenji Kadota, Joseph Silk, Phys.Rev. D90 (2014) 8, 083522
              Kenji Kadota, Yi Mao, Kiyomoto Ichiki, Joseph Silk, JCAP 1406 (2014) 011
              Ilidio Lopes, Kenji Kadota, Joseph Silk, Astrophys.J.Lett. 780 (2014) L15
      Comment : Seminar  (start at 15:30-)

  • November 13, 2015
       De Sitter vacua from a D-term generated racetrack potential
                                    in hypersurface Calabi-Yau compactifications

        T. Kobayashi (Hokkaido Univ.)
      E-PRINT :  Andreas P. Braun, Markus Rummel, Yoske Sumitomo, Roberto Valandro, arXiv:1509.06918[hep-th]
      Comment : Journal Club

       Supersymmetry and Grand Unified Theory
        N. Fukuhara (Hokkido Univ.)
      Comment : M1 Journal Club

  • November 20, 2015
       Constraints on Dark Matter in the Inert Doublet Model from Run1 of LHC
        E. Park (Hokkaido Univ.)
      E-PRINT :  A. Goudelis,
             "Status of the Inert Doublet Model of dark matter after Run-1 of the LHC",arXiv: 1510.03993[hep-ph]
              G. Belanger, B. Dumont, A. Goudelis, B. Herrmann, S. Kraml, D. Sengupta,
           "Dilepton constraints in the in the Inert Doublet Model from Run1 of the LHC", arXiv:1503.07367[hep-ph]
      Comment : Journal Club

  • November 27, 2015
        Y. Shimizu (KIAS)
       Neutrino physics and non-Abelian discrete flavor symmetry
      Abstract :  The experiments of neutrino oscillation go into a new phase of precise determination of the
              mixing angles and mass squared differences. The T2K experiment, which has already confirmed
              the neutrino oscillation in the \( \nu _\mu \) \(\to\) \(\nu _e\) appearance events, provides us the new information of
              the CP violating Dirac phase by combining the data of reactor experiments.
              We discuss the neutrino flavor model by using non-Abelian discrete symmetry as flavor symmetry
              in order to explain these experimental results.
      Comment : Morning Session

       Relation between Dirac and Majorana phases in \(S_4\) model of neutrinos
      Abstract :  We present two new simple lepton flavor models in the framework of the \(S_4\) flavor symmetry.
              We discuss the neutrino mass matrices, which are given by two complex parameters. In our model,
              because of the less parameters, we predict the only inverted mass hierarchy. The charged lepton
              mass matrix has the 1-2 lepton flavor mixing, which gives the non-vanishing reactor angle \(\theta _{13}\).
              These models predict the Dirac phase and the Majorana phases, which are testable in the
              future experiments.
      Comment : Afternoon Session

      E-PRINT :  H. Ishimori, T. Kobayashi, H. Ohki, Y. Shimizu, H. Okada and M. Tanimoto,
                                  Prog. Theor. Phys. Suppl. 183 (2010) 1, arXiv:1003.3552 [hep-th]
              Y. Shimizu, M. Tanimoto and A. Watanabe,
                                     Prog. Theor. Phys. 126 (2011) 81, arXiv:1105.2929 [hep-ph]
              Y. Shimizu, M. Tanimoto and K. Yamamoto,
                                  Mod. Phys. Lett. A30 (2015) 1550002, arXiv:1405.1521 [hep-ph]
              Y. Shimizu and M. Tanimoto, arXiv:1507.06221 [hep-ph]


  • December 4, 2015
       Entanglement Holography
        R. Nakayama (Hokkaido Univ.)
      E-PRINT :  J. de Boer, M.P. Heller, R.C. Meyers and Y. Neiman, arXiv:1509.00113 [hep-th]
      Comment : Journal Club

       Conformal Symmetry
        Y. Nishimura (Hokkido Univ.)
      Comment : M1 Journal Club

  • December 11, 2015
       From Data to Models to Theories
        Pyungwon Ko (KIAS)
      Comment : Seminar  (start at 13:30-)

       Noether's Theorem in Field Theory
        K. Ueda (Hokkido Univ.)
      Comment : M1 Journal Club

  • December 18, 2015
       Generalized Global Symmetries
        N. Shimode (Hokkido Univ.)
      E-PRINT :  [1] Davide Gaiotto, Anton Kapustin, Nathan Seiberg, Brian Willett, arXiv:1412.5148[hep-th]
              [2] Eric Sharpe, arXiv:1508.04770[hep-th]
      Comment : Journal Club


  • January 15, 2016
       Non-planar operator mixing and negative anomalous dimensions
        Y. Kimura (OIQP)
      Abstract :  We study the one-loop anomalous dimension of so(6) singlet multi-trace operators in N=4 Super
              Yang-Mills theory. We will first review the operator mixing problem.
              The main part of this talk is based on work with Ryo Suzuki [1503.06210], where it is shown that
              the planar zero modes get a negative anomalous dimension by including non-planar corrections.
      Comment : Seminar

       Relaxion from N axions
        Kiwoon Choi (CTPU, IBS)
      Abstract :  The relaxion mechanism which was proposed recently to solve the gauge hierarchy problem requires
              a big hierarchy between the involved axion scales. In this talk, I discuss a novel scheme to generate
              a big hierarchy in axion scales, without introducing a fine tuning of continuous parameters or an
              unreasonably large number of degrees of freedom.
      Comment : Seminar

  • January 22, 2016
      Toward the Standard Model from SO(32) heterotic string theory
        T. Tatsuishi (Hokkaido Univ.)
      Comment : Rehearsal of Master Thesis Presentation (Morning Session)

      Domain Wall in the NMSSM
        N. Omoto (Hokkaido Univ.)
      Comment : Rehearsal of Master Thesis Presentation (Afternoon Session)

  • January 29, 2016
      TITLE : TBA
        A. Kaneko (Hokkaido Univ.)
      Comment : Rehearsal of Master Thesis Presentation (Morning Session)

      dS/CFT correspondence and boundary conditions at future infinity
        T. Suzuki (Hokkaido Univ.)
      Comment : Rehearsal of Master Thesis Presentation (Afternoon Session)


  • February 5, 2016
       SO(32) heterotic string theoryにおける素粒子標準模型の導出に向けた研究
        T. Tatsuishi (Hokkaido Univ.)
        N. Omoto (Hokkaido Univ.)
       Phenomenological Constraints on Neutralino Dark Matter in cMSSM
        A. Kaneko (Hokkaido Univ.)
        T. Suzuki (Hokkaido Univ.)
      Comment : Short Rehearsal of Master Thesis Presentation (start at 10:30-)

       Majorana Dark Matter Search: Pure Singlet and Singlet-Doublet mixed Case
        Yue-Lin Sming Tsai (IPMU)
      Abstract :  Majorana Dark matter (DM) model can be classified by their electroweak charge. In this talk I will
             start with singlet DM effective theory (EFT) and then move to singlet-doublet mixed case.
             In singlet case, we will present a global picture by taking all the operators and DM constraints into
             account. However, the EFT is no longer valid with current LHC 8 TeV region. Therefore, by the help
             from UV models, this problem can be fixed non-trivially. The current monojet and dijet constraint
             power will be presented. Moreover, a future prospect on the future DM direct detections and e+e-
             colliders (CEPC and ILC) will be also demonstrated. In the second part of talk, I will show some of
             our preliminary result on singlet-doublet mixed DM model by using the similar manner. The present,
             near future, and far future status of singlet-doublet mixed DM will be shown in this seminar.
      Comment : Seminar (start at 13:30-)

  • February 8-10, 2016 
        H. Sakamoto (Tokyo Univ.)
      Comment : Intensive Lecture  

  • February 12, 2016
       TITLE : TBA
        B. -H. Lee (APCTP)
      Comment : Seminar

  • February 19, 2016
       Matrix Model Regularization of Super Yang-Mills
        N. Kawamoto (Hokkido Univ.)
      Abstract :  I try to explain “ How matrix model can avoid lattice SUSY difficulties and keep exact
              supersymmetry even after regularization ? ”based on the works by A.Tsuchiya et. al.
      Comment : Journal Club

  • February 22, 2016
       An entanglement analogue in light cones
        F. Morikoshi (NTT Basic Research Laboratories)
      Comment : Informal Seminar (start at 13:30-)

  • February 26, 2016
       Complete action of open superstring field theory
        Y. Okawa (Tokyo Univ.,Komaba)
      Abstract :  In formulating superstring field theory, construction of an action including the Ramond sector
              has not been successful for about thirty years, and this has been a major obstacle. This August
              we finally succeeded in constructing a gauge-invariant action of open superstring field theory
              including both the Neveu-Schwarz sector and the Ramond sector. This is the first construction
              of a complete formulation of superstring field theory. In this talk, we explain the construction of
              the complete action without assuming any background on string field theory. The talk is based on
              the paper arXiv:1508.00366 in collaboration with Kunitomo.
      Comment : Seminar

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