Hidden GeV-scale interactions of quarks

Area of Science:

• High Energy Physics
• Particle Physics
• Beyond Standard Model Physics

Background:

• The Standard Model of particle physics successfully describes fundamental particles and forces, but does not explain phenomena like dark matter or neutrino masses.
• New gauge bosons, such as the Z' boson, are hypothetical particles predicted by extensions to the Standard Model that could mediate new interactions.

Purpose of the Study:

• To explore quark interactions mediated by new gauge bosons (Z' bosons) within a specific mass range (0.3-50 GeV).
• To establish constraints on the properties of these hypothetical Z' bosons, particularly their gauge couplings.

Main Methods:

• Analysis of anomaly cancellation conditions in particle physics theories.
• Application of collider bounds on the existence of new charged fermions.
• Investigation of quarkonium decays and electroweak constraints.
• Derivation of limits for a Z' boson coupled to baryon number.

Main Results:

• A tight upper limit on the gauge coupling of light Z' bosons was determined, influenced by anomaly cancellation and collider data.
• Quarkonium decay limits were found to be model-dependent, while electroweak constraints were relatively mild.
• Specific limits were derived for a Z' boson interacting with baryon number.
• A Z' boson model with relaxed constraints was constructed, permitting larger quark couplings (up to 0.2) for masses around a few GeV.

Conclusions:

• The study provides stringent constraints on the properties of light Z' bosons, impacting theories beyond the Standard Model.
• The derived limits are crucial for guiding future experimental searches for new gauge bosons.
• The proposed model with relaxed constraints opens new avenues for exploring Z' boson phenomenology in particle physics experiments.