The mass of the graviton and the cosmological constant puzzle

Abstract

We propose an interpretation of the cosmological constant puzzle - i.e., the enormous value of the ratio ${\rho }_{Pl}/{\rho }_{vac}\approx 10^{120}$- in terms of the total number of gravitons in the observable universe based on a recently discovered relationship between $\Lambda$ and the mass $m_g$ of the graviton.