Stringy explanation of $b\to s{\mathrm{\ell }}^{+}{\mathrm{\ell }}^{-}$ anomalies

We show that the recent anomalies in $b\to s{\mathrm{\ell }}^{+}{\mathrm{\ell }}^{-}$ transitions observed by the LHCb collaboration can be accommodated within string motivated models with a low mass $Z^{\mathrm{\prime }}$ gauge boson. Such $Z^{\mathrm{\prime }}$ gauge boson can be obtained in compactifications with a low string scale. We consider a class of intersecting D-brane models, in which different families of quarks and leptons are simultaneously realized at different D-brane intersections. The explanation of $b\to s{\mathrm{\ell }}^{+}{\mathrm{\ell }}^{-}$ anomalies via a stringy $Z^{\mathrm{\prime }}$ sets important restrictions on these viable D-brane constructions.