Jet signals for low mass strings at the LHC

The mass scale M_s of superstring theory is an arbitrary parameter that can be as low as few TeVs if the Universe contains large extra dimensions. We propose a search for the effects of Regge excitations of fundamental strings at LHC, in the process p p \to \gamma jet. The underlying parton process is dominantly the single photon production in gluon fusion, g g \to \gamma g, with open string states propagating in intermediate channels. If the photon mixes with the gauge boson of the baryon number, which is a common feature of D-brane quivers, the amplitude appears already at the string disk level. It is completely determined by the mixing parameter -- and it is otherwise model-(compactification-) independent. Even for relatively small mixing, 100 fb^{-1} of LHC data could probe deviations from standard model physics, at a 5\sigma significance, for M_s as large as 3.3 TeV.