Dear members,

 

We are pleased to announce two seminars by Prof. Kobayashi and Hajime Otsuka(Student).

 

Seminar 1 (July 7)

* Title: Natural inflation with and without modulations in string theory

* Speaker: Hajime Otsuka (Waseda Univ.)

* Date: 3:30 PM, July 7(TUE) 2015 (During the tea time)

* Place: CTPU Seminar Room

* Abstract: We propose a mechanism for the natural inflation with and without modulation in the framework of type IIB string theory on toroidal orientifold or orbifold. We explicitly construct the stabilization potential of complex structure, dilaton and K\"ahler moduli, where one of the imaginary component of complex structure moduli becomes light which is identified as the inflaton. The inflaton potential is generated by the gaugino-condensation term which receives the one-loop threshold corrections determined by the field value of complex structure moduli and the axion decay constant of inflaton is enhanced by the inverse of one-loop factor. We also find the threshold corrections can also induce the modulations to the original scalar potential for the natural inflation. Depending on these modulations, we can predict several sizes of tensor-to-scalar ratio as well as the other cosmological observables reported by Planck collaboration.

Seminar 2 (July 8)

* Title: Towards realistic models in SO(32) heterotic string theory

* Speaker: Tatsuo Kobayashi (Hokkaido Univ.)

* Date: 4:00 PM, July 8(WED) 2015

* Place: CTPU Seminar Room

* Abstract: We study model construction towards realisticmodels within the framework of SO(32) heterotic string theory. We consider torus compactification with magnetic fluxes. Then, we construct the models, which has the gauge group including SU(3)xSU(2)xU(1) and three chiral generations of quarks and leptons. We also study the gauge coupling unification.

 

We look forward to your participation in the seminars.

Thank you.

 

Sincerely,

Mijin Kim