Kentaro Yoshida, Kyoto University
Towards the gravity/CYBE correspondence
Seminar room, Kenkyu honkan 3F
We present a systematic way to consider integrable deformations of the AdS5×S5 superstring. It is based on classical r-matrices satisfying classical Yang-Baxter equation (CYBE). Then a classical r-matrix gives rise to a gravitational solution that describes a deformed AdS5×S5 geometry. In this seminar, we provide some examples including the Lunin-Maldacena backgrounds for beta deformations of N=4 super Yang-Mills,the Maldacena-Russo backgrounds for non-commutative gauge theories,and Schrodinger spacetimes dual for cold atoms.We present a systematic way to consider integrable deformations of the AdS5×S5 superstring. It is based on classical r-matrices satisfying classical Yang-Baxter equation (CYBE). Then a classical r-matrix gives rise to a gravitational solution that describes a deformed AdS5×S5 geometry.In this seminar, we provide some examples including the Lunin-Maldacena backgrounds for beta deformations of N=4 super Yang-Mills, the Maldacena-Russo backgrounds for non-commutative gauge theories, and Schrodinger spacetimes dual for cold atoms.
Sakine Nishi, Rikkyo University
Generalized Galilean Genesis
Room 345, 4 go-kan 3F
The galilean genesis scenario is an alternative to inflation in which the universe starts expanding from Minkowski in the asymptotic past by violating the null energy condition stably. Several concrete models of galilean genesis have been constructed so far within the context of galileon-type scalar-field theories. We give a generic, unified description of the galilean genesis scenario in terms of the Horndeski theory, i.e., the most general scalar-tensor theory with second-order field equations. In doing so we generalize the previous models to have a new parameter (denoted by \alpha) which results in controlling the evolution of the Hubble rate. The background dynamics is investigated to show that the generalized galilean genesis solution is an attractor, similarly to the original model. We also study the nature of primordial perturbations in the generalized galilean genesis scenario. In all the models described by our generalized genesis Lagrangian, amplification of tensor perturbations does not occur as opposed to what happens in quasi-de Sitter inflation. We show that the spectral index of curvature perturbations is determined solely from the parameter \alpha and does not depend on the other details of the model. In contrast to the original model, a nearly scale-invariant spectrum of curvature perturbations is obtained for a specific choice of \alpha.
Kazuhiro Tobe, Nagoya University
Lepton-flavor-violating Higgs decay $h \rightarrow \mu \tau$ and muon anomalous magnetic moment in a general two Higgs doublet model
Meeting Room 3, Kenkyu Honkan 1F
A two Higgs doublet model (2HDM) is one of the minimal extensions of the standard model (SM), and it is well-known that the general setup predicts the flavor-violating phenomena, mediated by neutral Higgs interactions. Recently the CMS collaboration has reported an excess of the lepton-flavor-violating Higgs decay in $h \rightarrow \mu \tau$ channel with a significance of $2.4 \sigma$. We investigate the CMS excess in a general 2HDM with tree-level flavor changing neutral currents (FCNSs), and discuss its impact on the other physical observations. Especially, we see that the FCNCs relevant to the excess can enhance the neutral Higgs contributions to the muon anomalous magnetic moment (muon g-2), and can resolve the discrepancy between the measured value and the SM prediction. We also find that the couplings to be consistent with the muon g-2 anomaly as well as the CMS excess in $h \rightarrow \mu \tau$ predict the sizable rate of $\tau \rightarrow \mu \gamma$, which is with in the reach of future B factory.
Tatsu Takeuchi 竹内 建, Virginia Tech
Matter Effect from Non-Standard Interactions of the Neutrino
Meeting Room 1, Kenkyu Honkan 1F
Neutrino oscillation in matter is sensitive to interactions between the neutrinos and the matter particles, including the Standard Model W-exchange interaction and any Non-Standard Interactions (NSI’s) that the neutrinos may have. In this talk, I will show how the Jacobi method can be utilized to find analytical expressions for the effective mixing angles and effective CP violating phase of the neutrinos in matter, which lead to extremely simple and compact expressions for the oscillation probabilities. All matter effects can be absorbed into the “running” of the effective parameters. It will be shown that the SM interactions cause theta12 and theta13 to run, while NSI’s involving the mu and tau neutrinos cause theta23 and delta to run. By looking at the “running” of the effective parameters, it is possible to find the best conditions under which the NSI effects will be manifest.
Kunio Kaneta, Institute for Cosmic Ray Research, U Tokyo
Spontaneous thermal leptogenesis
Meeting room1, Kenkyu honkan 1F Although cosmological and astrophysical observations have found the baryon asymmetry of the universe, the standard model of particle physics hardly explain its origin, and thus new physics beyond the standard model is required. Leptogenesis is one of convincing models for baryogenesis, in which tiny neutrino masses can be explained by the presence of right-handed Majorana neutrinos via seesaw mechanism. There, Majorana masses of the right-handed neutrinos would be originated from spontaneous symmetry breaking of $U(1)_{B-L}$, which can lead to a Nambu-Goldstone boson called Majoron. We discuss a possiblitity that leptogenesis takes place in the primordial thermal bath due to the background Majoron field in motion.
Although cosmological and astrophysical observations have found the baryon asymmetry of the universe, the standard model of particle physics hardly explain its origin, and thus new physics beyond the standard model is required. Leptogenesis is one of convincing models for baryogenesis, in which tiny neutrino masses can be explained by the presence of right-handed Majorana neutrinos via seesaw mechanism. There, Majorana masses of the right-handed neutrinos would be originated from spontaneous symmetry breaking of $U(1)_{B-L}$, which can lead to a Nambu-Goldstone boson called Majoron. We discuss a possiblitity that leptogenesis takes place in the primordial thermal bath due to the background Majoron field in motion.
（References)
・M.Ibe and K.Kaneta,“Spontaneous thermal Leptogenesis via Majoron oscillation,” arXiv:1504.04125 [hep-ph].
Shinya Aoki, Yukawa Institute for Theoretical Physics, Kyoto University
On the definition of entanglement entropy in lattice gauge theories
Meeting room 1, Kenkyu honkan 1F
We focus on the issue of proper definition of entanglement entropy in lattice gauge theories, and examine a naive definition where gauge invariant states are viewed as elements of an extended Hilbert space which contains gauge non-invariant states as well. Working in the extended Hilbert space, we can define entanglement entropy associated with an arbitrary subset of links, not only for abelian but also for non-abelian theories. We then derive the associated replica formula. We also discuss the issue of gauge invariance of the entanglement entropy.In the $Z_N$ gauge theories in arbitrary space dimensions, we show that all the standard properties of the entanglement entropy, e.g. the strong subadditivity, hold in our definition. We study the entanglement entropy for special states, including the topological states for the $Z_N$ gauge theories in arbitrary dimensions. We discuss relations of our definition to other proposals.
安井繁宏, 東工大
[近藤問題に関する連続セミナー] クォーク物質におけるQCD近藤効果
研究本館3階セミナー室
倉本義夫, KEK
[近藤問題に関する連続セミナー] 近藤効果の理論的意義と最近の発展
研究本館3階セミナー室
Anupam Mazumdar, Lancaster U
Understanding Gravity
Meeting room 1, Kenkyu honkan 1F
I will discuss how gravity in ultraviolet and infrared can be understood in such a way that it can ameliorate some of the singularity problems of nature and also provide some hints to the pertinent question of cosmological constant.
Mauricio Romo, Kavli IPMU
Two-dimensional supersymmetric field theories with boundaries
Meeting room1, Kenkyu honkan 1F I will discuss recent progress on a particular class of 2d supersymmetric field theories on the disk: N=(2,2) Witten’s gauged linear sigma models. These theories are closely related to string compactifications on Calabi-Yau 3-folds, and so, the results have not only physical but also interesting mathematical consequences.
