PHYSICS H

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STRONG INTERACTION-between all particles made of quarks.

3-4 fm

strongest of all forces

attractive OR repulsive

Keeps nucleons together in nucleus

MEDIATED BY GLUONS.

Overcomes electrostatic repulsion between protons.

Keeps nucleus stable

REPULSIVE below 0.5fm-prevent nucleus collapsing/prevents p/n pushing into each other.

NO EFFECT after 4fm

MEDIATED by PIONS.

Roles of exchange particles--determine the strength and range of interaction.

Virtual Photon-REST MASS=0 ChARGE=0 Range=INFINITE

W+, w- boson restmass=non0 charge=+/- Range=0.001fm

Alpha Decay happens in big atoms--nuclei too big for strong force to keep it stable

Beta Decay--

Through weak interaction

Beta+, Beta-

Beta+ ---> Proton decays into neutron, emitting a positron, e-neutrino.

Beta- ----> Neutron decays into proton, emitting an electron, e-antineutrino