# I Range of Fundametal Forces

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1. Jun 14, 2016

### Surya97

How come gravity and electromagnetism have an infinite range, while the strong nuclear force dies out quickly? I understand that the weak force's bosons, the W+, W- and Z (neutral), have relatively large mass, and decay quickly, while the photon and the graviton (theoretical carrier of gravity) both have zero mass (we have now proved the existence of gravitational waves), giving both an infinite range. However, the strong force's carrier, the gluon, also theoretically has zero mass (experimentally, the maximum mass bound is very low). So how come the strong force turns from attractive to repulsive to nonexistent after the distance is increased (QCD), rather than going on forever?

2. Jun 15, 2016

### Orodruin

Staff Emeritus
Unlike photons (and presumably gravitons), gluons interact with themselves. This leads to quark confinement and screening of colour charge. A baryon is color neutral just as atom is electrically neutral despite its charged constituents. There is a residual strong force that may be thought of as mediated by pions. This has a short range due to pions being massive.