Koji Ishiwata, Kanazawa University
Grand Unification and Subcritical Hybrid Inflation
Meeting room 1, Kenkyu honkan 1F
We consider hybrid inflation for small couplings of the inflaton to matter such that the critical value of the inflaton field exceeds the Planck mass. It has recently been shown that inflation then continues at subcritical inflaton field values where quantum fluctuations generate an effective inflaton mass. The effective inflaton potential interpolates between a quadratic potential at small field values and a plateau at large field values. An analysis of the allowed parameter space leads to predictions for the scalar spectral index n_s and the tensor-to-scalar ratio r similar to those of natural inflation. Using the ranges for n_s and r favored by the Planck data, we find that the energy scale of the plateau is constrained to the interval (1.6 − 2.4) × 10^16 GeV, which includes the energy scale of gauge coupling unification in the supersymmetric standard model. The tensor-to-scalar ratio is predicted to satisfy the lower bound r > 0.049 for 60 e-folds before the end of inflation.
Lev Vaidman, Tel Aviv University
Counterfactual Communication
Seminar Room, Kenkyu Honkan 3F
Counterfactual communication is a communication without particles in the transmission channel. Since there are no particles to observe, it apparently cryptographically secure because Eve has nothing to eavesdrop on. However, the issue is highly controversial. I will describe: interaction-free measurements, counterfactual key distribution, and direct counterfactual communication protocols. Analyzing the weak trace left in the transmission channel, I will argue that counterfactual communication is possible only for one bit value.
Lev Vaidman, Tel Aviv University
Asking Photons Where They Have Been
Seminar room, Kenkyu honkan 3F
Experimental evidence obtained from photons passing through a nested Mach-Zehnder interferometer shows that they have been in the parts of the interferometer through which they could not have possibly pass. The meaning of these results and numerous objections are discussed. It is argued that the most simple and clear explanation is given in the framework of the two-state vector formalism of quantum theory.
Cédric Weiland, Autonomous University of Madrid
The CMS excess and lepton flavour violation in the (supersymmetric) inverse seesaw
Meeting Room, Kenkyu honkan 3F
The existence of neutrino oscillations calls for an extension of the Standard Model that would generate neutrino masses and mixing. We focused for these studies on a typical low-scale seesaw mechanism, the inverse seesaw, and its supersymmetric realization. New fermionic gauge singlets around the TeV scale with potentially large couplings lead to a rich phenomenology. After introducing the models considered, I will present their predictions for 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.
Junichiro Kawamura, Waseda Univ.
LHC phenomenology of natural MSSM with non-universal gaugino masses at the unification scale
Meeting Room 322, Kenkyu Honkan 3F
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.
Yoshinori Matsuo, University of Crete
Hyperscaling-violating Lifshitz hydrodynamics from black-holes
Meeting Room 322, Kenkyu Honkan 3F
Non-equilibrium black hole horizons are considered in scaling theories with generic Lifshitz invariance and an unbroken U(1) symmetry. There is also a special form of hyperscaling violation associated with a non-trivial conduction exponent. The boundary stress tensor is computed and renormalized, and the associated hydrodynamic equations are derived. Upon a non-trivial redefinition of boundary sources associated with the U(1) gauge field, the equations are mapped to the standard non-relativistic hydrodynamics equations coupled to a mass current and an external Newton potentials. The shear viscosity to entropy ratio is the same as in the relativistic case.
Rainer Sommer, DESY
The strong coupling from lattice QCD
Room 244, 4 go-kan 2F
After an introduction into what the strong coupling is, and how QCD discretized on a space-time lattice works, I discuss which methods are available to use lattice QCD in order to extract the strong coupling from experimental information. I then briefly review the status of these computations including the world average of the FLAG2 review and more recent developments.
Satoshi Ohya, Institute Quantum Science, Nihon University
BPS Monopole in the Space of Boundary Conditions
Seminar room, Kenkyu honkan 3F
The space of all possible boundary conditions that respect self-adjointness of Hamiltonian operator is known to be given by the group manifold U(2) in one-dimensional quantum mechanics. In this talk we study non-Abelian Berry’s connections in the space of boundary conditions in a simple quantum mechanical system: We consider a system for a free spinless particle on a circle with two point-like interactions described by the U(2) ¥times U(2) family of boundary conditions. We show that, for a certain SU(2) ¥subset U(2) ¥times U(2) subfamily of boundary conditions, all the energy levels become doubly-degenerate thanks to the so-called higher-derivative supersymmetry, and non-Abelian Berry’s connection in the ground-state sector is given by the Bogomolny-Prasad-Sommerfield (BPS) monopole of SU(2) Yang-Mills-Higgs theory. We also show that, in the ground-state sector of this quantum mechanical model, matrix elements of position operator give the adjoint Higgs field that satisfies the BPS equation. It is also discussed that Berry’s connections in the excited-state sectors are given by non-BPS ‘t Hooft-Polyakov monopoles.
Kai Schmitz, IPMU
Leptogenesis during Axion Relaxation after Inflation
Meeting Room 322, Kenkyu Honkan 3F
In this talk, I present a novel and minimal alternative to thermal leptogenesis, which builds upon the assumption that the electroweak gauge bosons are coupled to an axion-like scalar field, as it is, for instance, the case in certain string compactifications. The motion of this axion-like field after the end of inflation generates an effective chemical potential for leptons and antileptons, which, in the presence of lepton number-violating scatterings mediated by heavy Majorana neutrinos, provides an opportunity for baryogenesis via leptogenesis. In contrast to thermal leptogenesis, the final baryon asymmetry turns out to be insensitive to the masses and CP-violating phases in the heavy neutrino sector. Moreover, the proposed scenario requires a reheating temperature of at least O(10^12) GeV and it is, in particular, consistent with heavy neutrino masses close the scale of grand unification. This talk is based on recent work (Phys. Rev. Lett. 115 (2015) 1, 011302, 1412.2043 [hep-ph]) in collaboration with Alexander Kusenko from UCLA and Tsutomu T. Yanagida from Kavli IPMU.”
Emi Kou, Orsay, Laboratoire de l'Accélérateur Linéaire
B2TiP and highlight of Belle II physics
Meeting room 1, Kenkyu honkan 1F
