X and Y bosons

X and Y bosons

Composition	Elementary particle
Statistics	Bosonic
Status	Hypothetical
Types	12
Mass	≈ 1015 GeV/c2
Decays into	X: two quarks, or one antiquark and one charged antilepton Y: two quarks, or one antiquark and one charged antilepton, or one antiquark and one antineutrino
Electric charge	X: +4/3 e Y: +1/3 e
Color charge	triplet or antitriplet
Spin	1
Spin states	3
Weak isospin projection	X: +1/2 Y: −1/2
Weak hypercharge	5/3
B − L	2/3

In particle physics, the X and Y bosons (sometimes collectively called "X bosons") are hypothetical elementary particles analogous to the W and Z bosons, but corresponding to a new type of force predicted by the Georgi–Glashow model, a grand unified theory.

Details

The X and Y bosons couple quarks to leptons, allowing violation of the conservation of baryon number, and thus permitting proton decay.

An X boson would have the following decay modes:

X → u + u

X → e+ + d

where the two decay products in each process have opposite chirality, u is an up quark, d is a down antiquark and e+ is a positron.

A Y boson would have the following decay modes:

Y → e+ + u

Y → d + u

Y → d + ν
e

where the first decay product in each process has left-handed chirality and the second has right-handed chirality and ν
e is an electron antineutrino.

Similar decay products exist for the other quark-lepton generations

In these reactions, neither the lepton number (L) nor the baryon number (B) is conserved, but B − L is. Different branching ratios between the X boson and its antiparticle (as is the case with the K-meson) would explain baryogenesis.

See also

• B − L
• Grand unification theory
• Proton decay
• W' and Z' bosons
• Leptoquark