A bosonic open string in the critical dimension has Regge slope

PHYSICS · Subjective · Fermi University Physics · Particle Physics & Quantum Fields · Beyond the Standard Model · Beyond the Standard Model

Symmetry and Flavour, Ch The relativistic string: action, light-cone quantisation, spectrum and D-branes

Problem

\alpha' = 0.75\,\mathrm{GeV^{-2}}

. Using the mass formula

M^2 = (N-1)/\alpha'

for the open string ground state, find

M^2

for

N=0

and state what a negative value of

M^2

implies about the state.