李田军 教授学术报告
Title: The Three-Family N=1 Supersymmetric Pati-Salam Models from Type IIA String Theory on T^6/(Z_2 ×Z_2) Orientifold with Intersecting D6-Branes
Speaker: Prof. Tianjun Li （李田军）
Affiliation: Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）
Time: 14:00-15:00, Wednesday, 18th October, 2023 (UTC+8, Beijing Time)
Venue: Room 1502, Yifu Architecture Building, Sipailou Campus of Southeast University, Nanjing
（东南大学四牌楼校区逸夫建筑馆丘成桐中心1502室）
Abstract
We provide a systematic construction of three-family N=1 supersymmetric Pati-Salam models from Type IIA orientifolds on T^6/(Z_2 × Z_2) with intersecting D6-branes. All the gauge symmetries SU(4)_C × SU(2)_L × SU(2)_R arise from the stacks of D6-branes with U(n) gauge symmetries, while the hidden sector is specified by USp(n) D6-branes. The Pati-Salam gauge symmetry can be broken down to the SU(3)_C × SU(2)_L × U(1)_{B-L} × U(1)_{I_{3R}} via D6-brane splittings, and further down to the Standard Model (SM) via the D- and F-flatness preserving Higgs mechanism from massless open string states in a N=2 subsector. In addition, we propose a systematic method to construct all the possible three-family N=1 supersymmetric Pati-Salam models by solving all the common solutions for the RR tadpole cancellation conditions, N=1 supersymmetry conditions, and three generation conditions with deterministic algorithm. We show that there are only 33 independent models with different gauge coupling relations at string scale after modding out equivalent relations. In particular, there is one and only one independent model which has gauge coupling unification. Moreover, we can decouple the exotic particles in these models, realize the gauge coupling relation at string scale, and explain the SM fermion masses and mixings, etc.
Speaker
Tianjun Li is a Professor at the Institute of Theoretical Physics, Chinese Academy of Sciences. He obtained the B.S. degree in Theoretical Physics at Department of Physics, Wuhan University in July 1991, M.S. degree in Particle Physics at Institute of Theoretical Physics, Chinese Academy of Sciences in July 1994, and Ph.D. degree in Particle Physics and Minor in Mathematics at Department of Physics, University of Wisconsin-Madison in August 2000. He has been a Postdoctoral Research Associate at Department of Physics and Astronomy, University of Pennsylvania from September 2000 to August 2002, a Member at the Institute for Advanced Study, Princeton from September 2002 to August 2005, and a Professor at the Institute of Theoretical Physics, Chinese Academy of Sciences since October 2005. He has been awarded the J. Van Vleck Fellowship at University of Wisconsin-Madison, and a Fellowship at the Institute for Advanced Study, Princeton.