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Particle physics

Only left-handed particles decay

Nature volume 524, page 8 (06 August 2015) | Download Citation


Only subatomic particles with a left-handed spin decay as a result of one of the fundamental forces, confirming that the Universe has a left-hand bias.

A team working on the LHCb experiment looked at the decay of trillions of subatomic particles known as Λb0 baryons emerging from collisions at the Large Hadron Collider at CERN, Europe's particle-physics laboratory near Geneva, Switzerland. During this decay, a bottom quark from the baryon can turn into an up quark. The team confirmed that the weak nuclear force — one of the four fundamental forces in the Universe — causes only bottom quarks with left-handed spin to decay into up quarks, as predicted by the standard model of particle physics.

Previous measurements had suggested that right-handed quarks might also decay in this way, which, if true, would have called for new fundamental forces of nature.

Nature Phys. (2015)

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