Yasuyuki Hatsuda, Rikkyo University
Borel resummation and S-duality in SL(2) Chern-Simons theory
Meeting room 3, Kenkyu honkan 1F
I will talk about an S-duality in SL(2) Chern-Simons theory. A perturbative semiclassical expansion does not have this symmetry, but its Borel resummation turns out to recover the exact S-dual symmetry.
Massimo Passera, INFN Padova
Measuring the leading hadronic contribution to the muon g-2 via muon-electron scattering
Seminar room, Kenkyu honkan 3F
I will present a recent proposal to determine the leading hadronic contribution to the muon g-2 via the measurement of the running of the electromagnetic coupling constant in the space-like region, by scattering high-energy muons on atomic electrons of a low-Z target.
Varun Sethi, University of Delhi
Finite Temperature Corrections to Tachyon Mass in Intersecting D-branes and Stacks of D-branes
Meeting room 1, Kenkyu honkan 1F, slides (kek.jp only)
In arXiv:1104.2843, a microscopic top-down model of a holographic superconductor is constructed using two intersecting D8-branes in the bulk in D4-brane background. This is a non-BPS configuration which has tachyons in its spectrum signaling instability of the system. This instability has been proposed to be the bulk analogue of the BCS instability in the boundary theory in 1104.2843. Our aim is to study a similar simplified system at finite temperature and evaluate the transition temperature. We thus consider a system of two intersecting D3 -branes in flat background, we compute one-loop finite temperature correction to tachyon two-point amplitude and find, numerically, the transition temperature at which effective mass-squared of the tachyon becomes zero. We further extend the calculation of tachyon two-point amplitude to the case of intersecting stacks of D3-branes.
Seiji Terashima, Yukawa Institute for Theoretical Physics
AdS/CFT Correspondence in Operator Formalism
Meeting room 3, Kenkyu honkan 1F
In this paper we study the AdS/CFT correspondence in the operator formalism without assuming the GKPW relation. We explicitly show that the low energy spectrum of the large N limit of CFT, which is realized by a strong coupling gauge theory, is identical to the spectrum of the free gravitational theory in the global AdS spacetime under some assumptions which are expected to be valid. Thus, two theories are equivalent for the low energy region under the assumptions. Using this equivalence, the bulk local field is constructed and the GKPW relation is derived.
Wen Yin, IHEP Chinese Academy of Sciences
Higgs-Anomaly Mediation: a simple setup with interesting phenomena and flavor safety
Meeting room 1, Kenkyu honkan 1F
We consider a simple setup, called Higgs-Anomaly mediation, where all the multiplets in the MSSM except for the Higgs multiplets are sequestered from SUSY breaking, but the Higgs multiplets couple to through Planck-suppressed operators. In this setup, the splitting mass spectra of squarks and sleptons are generated through radiative corrections: anomaly mediation and a kind of Higgs mediation. Despite the stop masses greater than order 10 TeV favored by the measured mass of the Higgs boson, sfermions in first two generations can be sufficiently light to be searched for and tested in the LHC, and affect low energy phenomena in ground-based experiments. There are viable regions explaining muon g-2 anomaly, and bottom-tau and top-bottom-tau Yukawa unifications. These regions are testable from the viewpoint of collider experiments. Surprisingly, despite the splitting mass spectra, there are suppressed flavor-violating processes. In fact, the contribution to epsilon_K is constrained most severely. However, we show that this contribution is at most around 20% of the experimental value and is safely within the theoretical uncertainty of the SM.
Kazuki Sakurai, University of Warsaw
Natural and Unnatural SUSY in light of Proton Decay and Gauge Unification
Meeting room 1, Kenkyu honkan 1F
I present the recent study on natural and unnatural SUSY in light of the proton decay and gauge unification. We show that the low energy SUSY mass spectrum is linked to the proton decay via the unification scale, and future nucleon decay experiments will provide a non-trivial upper bound on the superpartner masses. We also show that the mirage mediation provides a consistent picture of natural SUSY. For unnatural SUSY, we present a systematic study on split SUSY and predict a unique spectrum, which could be around the corner of discovery.
Aya Ishihara, Chiba U
Recent progresses on the neutrino astronomy from IceCube
Meeting room 1, Kenkyu honkan 1F
IceCube is a cubic kilometer scale, deep-ice Cherenkov neutrino detector at the South Pole. IceCube’s cosmic neutrino searches cover an energy region all the way from TeV and less to EeV and higher. Following the first observation of PeV neutrino events and successful measurements of high energy extraterrestrial neutrino flux in the energy region between a few tens of TeV and PeV significantly above the atmospheric neutrino background flux by IceCube, the field of neutrino astrophysics is becoming more and more active. Also in the EeV energy region, a flux of ‘cosmogenic’ neutrinos generated by interactions of ultra-high energy cosmic rays on intervening radiation backgrounds is expected. The cosmogenic neutrinos will give us insight into the sources of the ultra-high energy cosmic- rays (UHECRs). In this talk, I review the recent results from IceCube on cosmic neutrino observations. In particular I highlight the multi-messenger observation using the neutrino as the trigger for the gamma-ray/x-ray/optical telescopes, and constraints on the UHECR sources from the observation of cosmogenic neutrinos. Finally I discuss the future prospects for such activities.
Ryuji Daido, Tohoku University
Enhanced axion-photon coupling in a GUT with hidden photon
Seminar room, Kenkyu honkan 3F
We first review current status of QCD axion searches, which generically rely on interaction between the axion and SM photon. Next, we show that the axion-photon coupling is modified in the presence of massless hidden photon which has kinetic mixing with the SM photon. If the kinetic mixing and hidden gauge coupling are \mathcal{O}(1), the axion-photon coupling becomes several tens of times larger. Finally, we consider QCD axion in SU(5) GUT with massless hidden photon. Gauge coupling unification is determined by the size of kinetic mixing only, and requires relatively large kinetic mixing, which is naturally generated when hidden gauge coupling is large. We find enhancement factor of axion-photon coupling is about 20 in our model.
Yoshio Kikukawa, University of Tokyo
On the gauge invariant path-integral measure for the overlap Weyl fermions in 16 of SO(10)
Seminar room, Kenkyu honkan 3F
We consider the lattice formulation of SO(10) chiral gauge theory with left-handed Weyl fermions in the sixteen dimensional spinor representation (16) within the framework of the Overlap fermion/the Ginsparg-Wilson relation. We propose a manifestly gauge invariant path-integral measure for the left-handed Weyl field using the whole components of the Dirac field, but the right-handed part of which is just saturated completely by inserting a suitable product of the SO(10)-invariant ‘t Hooft vertices in terms of the right-handed field. The definition of the measure applies to all possible topological sectors. The measure possesses all required transformation properties under lattice symmetries and the induced effective action is CP invariant. The global U(1) symmetry of the left-handed field is anomalous due to the non-trivial transformation of the measure, while that of the right-handed field is explicitly broken by the ‘t Hooft vertices. There remains the issue of locality in the gauge-field dependence of the Weyl fermion measure, but the question is well-defined and can be addressed in the weak gauge-coupling expansion at least using Monte Carlo methods without encountering the sign problem.
Yuhma Asano, Dublin Institute for Advanced Studie
Phase transitions in the BMN matrix model
Seminar room, Kenkyu honkan 3F
