Gray, James | Search NASA

DOE OSTI2017

String Phenomenology 2017 (Conference)

The sixteenth annual International conference in the String Phenomenology series was held at Virginia Tech, Blacksburg on July 3rd - 7th 2017. String Phenomenology 2017 was organized by Professor Lara Anderson and Professor James Gray, with help from two postdoctoral fellows, Seung-Joo Lee and Xin Gao and Professors Eric Sharpe and Djordje Minic. The scientific program was chosen broadly from within the discipline of string phenomenology and related areas of mathematics and physics. Thus, the conference brought together researchers from a wide variety of related fields in order to discuss progress in relating string compactifications to low energy physics and stimulate future developments in such directions. This report summarizes the outcome of the conference.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2016

Matter in transition

In this study, we explore a novel type of transition in certain 6D and 4D quantum field theories, in which the matter content of the theory changes while the gauge group and other parts of the spectrum remain invariant. Such transitions can occur, for example, for SU(6) and SU(7) gauge groups, where matter fields in a three-index antisymmetric representation and the fundamental representation are exchanged in the transition for matter in the two-index antisymmetric representation. These matter transitions are realized by passing through superconformal theories at the transition point. We explore these transitions in dual F-theory and heterotic descriptions, where a number of novel features arise. For example, in the heterotic description the relevant 6D SU(7) theories are described by bundles on K3 surfaces where the geometry of the K3 is constrained in addition to the bundle structure. On the F-theory side, non-standard representations such as the three-index antisymmetric representation of SU(N) require Weierstrass models that cannot be realized from the standard SU(N) Tate form. We also briefly describe some other situations, with groups such as Sp(3), SO(12), and SU(3), where analogous matter transitions can occur between different representations. For SU(3), in particular, we find a matter transition between adjoint matter and matter in the symmetric representation, giving an explicit Weierstrass model for the F-theory description of the symmetric representation that complements another recent analogous construction.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗