Physics:Quantum W and Z bosons
Quantum W and Z bosons are massive gauge bosons that mediate the weak interaction. The charged W bosons are responsible for charged-current processes such as beta decay, while the neutral Z boson mediates neutral-current weak interactions. Their masses and couplings are central evidence for electroweak theory.[1][2][3]
Weak interactions
W bosons change electric charge and can change particle flavor, allowing processes such as neutron beta decay and neutrino charged-current scattering. The Z boson mediates weak interactions without changing electric charge, appearing in neutral-current scattering and in electron-positron annihilation studies.
Electroweak theory
In the Standard Model, W and Z bosons arise from the electroweak gauge fields after symmetry breaking. Their large masses make weak interactions short-ranged compared with electromagnetism. Precision measurements of their masses, widths, and couplings test the consistency of the electroweak sector.[4]
Experimental signatures
W bosons are often reconstructed from charged leptons plus missing transverse momentum or from hadronic jets. Z bosons are identified cleanly through lepton-antilepton pairs with invariant mass near the Z resonance. These signatures are calibration tools and backgrounds for many collider searches.
See also
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References
- ↑ Particle Data Group (2022). "Review of Particle Physics". Progress of Theoretical and Experimental Physics 2022 (8): 083C01. doi:10.1093/ptep/ptac097.
- ↑ Arnison, G. (1983). "Experimental observation of isolated large transverse energy electrons with associated missing energy at sqrt(s) = 540 GeV". Physics Letters B 122 (1): 103-116. doi:10.1016/0370-2693(83)91177-2.
- ↑ Arnison, G. (1983). "Experimental observation of lepton pairs of invariant mass around 95 GeV/c² at the CERN SPS collider". Physics Letters B 126 (5): 398-410. doi:10.1016/0370-2693(83)90188-0.
- ↑ Schwartz, Matthew D. (2014). Quantum Field Theory and the Standard Model. Cambridge University Press. ISBN 978-1-107-03473-0.
Source attribution: W and Z bosons