Inflation with TeV-scale gravity needs supersymmetry

Allowing for the possibility of large extra dimensions, the fundamental Planck scale M could be anywhere in the range TeV≲M≲MP, where MP=2.4×1018 GeV is the four-dimensional Planck scale. If M∼ TeV, quantum corrections would not destabilize the Higgs mass even if there were no supersymmetry. But we point out that supersymmetry must in fact be present, if there is an era of cosmological inflation, since during such an era the inflaton mass satisfies m≪M2/MP=10−15(M/ TeV) and supersymmetry will be needed to protect it. If the inflation hypothesis is accepted, there is no reason to think that Nature has chosen the low value M∼ TeV, however convenient that choice might have been for the next generation of collider experiments.