W and Z bosons

In <a href="/facts/Particle_physics/YgIuyj2t">particle physics</a>, the W and Z bosons are <a href="/facts/Vector_boson/j1XJ5QMW">vector bosons</a> that are together known as the weak bosons or more generally as the intermediate vector bosons. These <a href="/facts/Elementary_particle/CTFDM97U">elementary particles</a> <a href="/facts/Force_carrier/zpF4Tyaa">mediate</a> the <a href="/facts/Weak_interaction/f6upmKMs">weak interaction</a>; the respective symbols are W+, W−, and Z0. The W± bosons have either a positive or negative <a href="/facts/Electric_charge/xxsBfmlB">electric charge</a> of 1 <a href="/facts/Elementary_charge/lPcj6CoQ">elementary charge</a> and are each other's <a href="/facts/Antiparticle/7Ic43ThI">antiparticles</a>. The Z0 boson is electrically <a href="/facts/Neutral_particle/pQbmxaaE">neutral</a> and is its own antiparticle. The three particles each have a <a href="/facts/Spin_(physics)/4Jvp7e8P">spin</a> of 1. The W± bosons have a magnetic moment, but the Z0 has none. All three of these particles are very short-lived, with a <a href="/facts/Half-life/kGVH8BAB">half-life</a> of about 3×10−25 s. Their experimental discovery was pivotal in establishing what is now called the <a href="/facts/Standard_Model/LhVGf9ow">Standard Model</a> of <a href="/facts/Particle_physics/YgIuyj2t">particle physics</a>.
The W bosons are named after the weak force. The <a href="/facts/Physicist/cQcgvSIm">physicist</a> <a href="/facts/Steven_Weinberg/G61D6kJw">Steven Weinberg</a> named the additional particle the "Z particle", and later gave the explanation that it was the last additional particle needed by the model. The W bosons had already been named, and the Z bosons were named for having zero electric charge.
The two W bosons are verified mediators of <a href="/facts/Neutrino/yGWVfSg2">neutrino</a> absorption and emission. During these processes, the W± boson charge induces electron or positron emission or absorption, thus causing <a href="/facts/Nuclear_transmutation/MjlvjsV6">nuclear transmutation</a>.
The Z boson mediates the transfer of momentum, spin and energy when neutrinos scatter <a href="/facts/Elastic_scattering/51u9WlE1">elastically</a> from matter (a process which conserves charge). Such behavior is almost as common as inelastic neutrino interactions and may be observed in <a href="/facts/Bubble_chamber/awVVhk4G">bubble chambers</a> upon irradiation with neutrino beams. The Z boson is not involved in the absorption or emission of electrons or positrons. Whenever an electron is observed as a new free particle, suddenly moving with kinetic energy, it is inferred to be a result of a neutrino interacting with the electron (with the momentum transfer via the Z boson) since this behavior happens more often when the neutrino beam is present. In this process, the neutrino simply strikes the electron (via exchange of a boson) and then scatters away from it, transferring some of the neutrino's momentum to the electron.

W and Z bosons open-in-new

W and Z bosons