| Preprint | |
| Report number | arXiv:2507.21210 ; CERN-TH-2025-136 |
| Title | GSO Defects: IIA/IIB Walls and the Surprisingly Stable $\mathrm{R}7$-Brane |
| Author(s) | Heckman, Jonathan J. (Pennsylvania U., Dept. Math. ; Pennsylvania U.) ; McNamara, Jacob (Caltech) ; Parra-Martinez, Julio (IHES, Bures-sur-Yvette) ; Torres, Ethan (CERN) |
| Imprint | 2025-07-28 |
| Number of pages | 51 |
| Note | 51 pages, 15 figures |
| Subject category | math.MP ; Mathematical Physics and Mathematics ; math-ph ; Mathematical Physics and Mathematics ; hep-th ; Particle Physics - Theory |
| Abstract | The recently proposed Swampland Cobordism Conjecture predicts the existence of new non-supersymmetric objects which supplement the spectrum of low-energy gravitational effective field theories. In this paper, we study a subset of these defects related to the GSO projection on the string worldsheet. These include the predicted domain wall between Type IIA and IIB superstring theories and the newly-discovered $\mathrm{R}7$-brane. We study these defects in two different ways: via long-string probes and target-space effective field theory. We find that the $\mathrm{R}7$-brane can be identified with a collapsed cylindrical configuration of the IIA/IIB wall, and further, that the $\mathrm{R}7$-brane is stable, in contrast to previous expectations. Moreover, we argue that BPS D-branes pulled across the IIA/IIB wall become non-BPS D-branes, which we identify with fluxbrane configurations. We show that the non-BPS D-branes of either Type II theory are charged under a $\mathbb{Z}_2$ remnant of the Ramond-Ramond potentials of the other, which we identify with the mod 2 reduction of the Ramond-Ramond fluxes. Similar considerations provide a complementary perspective on the Heterotic ${\mathfrak{so}(32)}$ S-duals of known non-BPS 7- and 8-branes in Type I string theory. |
| Other source | Inspire |
| Copyright/License | preprint: (License: arXiv nonexclusive-distrib 1.0) |
Record created 2025-07-31, last modified 2025-09-19
