Long-Lived Heavy Quarks: A Review

Table 1

Vector-like multiplets allowed to mix with the SM quarks through Yukawa couplings. The electric charge is the sum of the third component of isospin 𝑇₃ and of the hypercharge 𝑌. Adapted from [9].

𝑄𝑞	𝑇2/3	𝐵−1/3	𝑋5/3𝑇2/3	𝑇2/3𝐵−1/3	𝐵−1/3𝑌−4/3	𝑋5/3𝑇2/3𝐵−1/3	𝑇2/3𝐵−1/3𝑌−4/3
𝑇3	0	0	1/2	1/2	1/2	1	1
𝑌	2/3	−1/3	7/6	1/6	−5/6	2/3	−1/3