Changes between Version 26 and Version 27 of UED6
- Timestamp:
- Apr 7, 2011, 6:12:06 AM (13 years ago)
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UED6
v26 v27 14 14 The particle spectra of 2UED includes all of the Standard Model particles, their Kaluza-Klein excitations in either one or both of the compactified extra dimensions, as well as scalar spinless adjoints to the excited vector gauge fields. Upon compactification one recovers the four dimensional gauge fields, but are left with two extra components. One of these components, the aforementioned scalar spinless adjoint to the gauge field, is invariant under 6D gauge transformations. The other, orthogonal excitation, shifts under such a transformation and corresponds to the Nambu-Goldstone boson eaten by the massive vector gauge field level by level. The 6D fermions have four components corresponding to the + or - 6D chiralities and the familiar L and R 4D chiralities. In order to insure 6D anomaly cancellation and fermion mass generation, the chiralities of the weak-doublet quarks (leptons) are forced to be opposite those of the weak-singlet quarks (leptons). That is, for each generation of quarks, there are the following fields: Q+ = (U+,D+), U-, D-, as well as the analogous fields for the leptons, including a - chirality neutrino field. Each of these 6D chiralities is composed of a combination of L and R handed components. Below is a table summarizing the 2UED particle content for the (0,0), (1,0) and (1,1) levels of excitation, where (0,0) are the standard model fields, (1,0) are fields with excitations in 1 extra dimension and (1,1) are fields with excitations in both extra dimensions. 15 15 16 Particles produced in this model must conserve Kaluza-Klein parity in their decays. That is, a (1,0) particle must decay to another (1,0) particle and a standard model particle. Conversely, standard model particles can only pair produce KK particles. There is an exception to this rule. If the interaction is localized on either of the conical singularities, KK number may be violated, while still preserving KK parity. For example, the process gg -> Gmu11 conserves the KK even parity, (2 (0,0) particles to 1 (1,1) particle), but does not preserve KK number. These KK number violating Lagrangian terms are what allows for the decay of Gmu11 and GH11to top quark pairs.16 Particles produced in this model must conserve Kaluza-Klein parity in their decays. That is, a (1,0) particle must decay to another (1,0) particle and a standard model particle. Conversely, standard model particles can only pair produce KK particles. There is an exception to this rule. If the interaction is localized on either of the conical singularities, KK number may be violated, while still preserving KK parity. For example, the process gg -> Gmu11 conserves the KK even parity, (2 (0,0) particles to 1 (1,1) particle), but does not preserve KK number. These KK number violating operators are what allows for Gmu11, GH11, as well as the other level (1,1) KK excitations of the gauge fields and their spinless adjoints to decay to top quark pairs. 17 17 18 18