Reconstructing BPS String Charge Cone in 6d N=(1,0) Supergravity
ABSTRACT
The tensor branch of six-dimensional $\mathcal N=(1,0)$ supergravity is characterized by a spectrum of BPS strings charged under the two-form gauge fields. Their charges span a cone in the tensor charge lattice, whose extremal rays are generated by primitive BPS string charges that become tensionless at the boundaries of the tensor moduli space. I will introduce a systematic procedure, based entirely on effective field theory data, to reconstruct the full set of primitive BPS string charges and thereby determine the complete BPS string cone of any 6d $\mathcal N=(1,0)$ supergravity theory. The key ingredients are the universal {\it H}-string, which allows us to isolate a fixed sector determined by classified LST blocks and gauge anomaly data from the remaining gauge-neutral E-string sector, and a BPS refinement of the Completeness Conjecture that ensures population of the relevant charge rays. I will further show that this reconstruction provides new constraints on the low-energy theory and can rule out EFTs that satisfy all currently known consistency conditions.
