Science Constants - Compton Wavelength, Proton h/mpc Symbol: λC,p Value: 1.321409847(10) × 10-15 m Category: - Proton Particle Constants Description: The Compton Wavelength is the wavelength associated with the mass of any particle, given by λ = h / mc, where h is Planck's Constant, m is the mass of the particle and c is the speed of light. The value quoted above is the Compton Wavelength for a proton particle.