English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We study an extension of the gauge group SU(3)_c X SU(2)_L X U(1)_Y of thestandard model to the symmetry group SU(3)_c X SU(4)_L X U(1)_X (3-4-1 forshort). This extension provides an interesting attempt to answer the questionof family replication in the sense that models for the electroweak interactioncan be constructed so that anomaly cancellation is achieved by an interplaybetween generations, all of them under the condition that the number offamilies must be divisible by the number of colours of SU(3)_c. This method ofanomaly cancellation requires a family of quarks transforming differently fromthe other two, thus leading to tree-level flavour changing neutral currents(FCNC) transmitted by the two extra neutral gauge bosons $Z'$ and $Z''$predicted by the model. In a version of the 3-4-1 extension, which does notcontain particles with exotic electric charges, we study the fermion massspectrum and some aspects of the phenomenology of the neutral gauge bosonsector. In particular, we impose limits on the $Z-Z'$ mixing angle and on themass scale of the corresponding physical new neutral gauge boson $Z_2$, andestablish a lower bound on the mass of the additional new neutral gauge boson$Z'' \equiv Z_3$. For the analysis we use updated precision electroweak data atthe Z-pole from the CERN LEP and SLAC Linear Collider, and atomic parityviolation data. The mass scale of the additional new neutral gauge boson $Z_3$is constrained by using updated experimental inputs from neutral meson mixingin the analysis of the sources of FCNC in the model. The data constrain the$Z-Z'$ mixing angle to a very small value of O(0.001), and the lower bounds on$M_{Z_2}$ and on $M_{Z_3}$ are found to be of O(1 TeV) and of O(7 TeV),repectively.

Phenomenology of a three-family model with gauge symmetry SU(3)_c X SU(4)_L X U(1)_X