Search for A^{'}→μ^{+}μ^{-} Decays.

Area of Science:

• High Energy Physics
• Particle Physics
• Cosmology

Background:

• Dark photons are hypothetical particles that could mediate interactions between the visible and dark sectors.
• Understanding dark photons is crucial for explaining dark matter and other cosmological phenomena.

Purpose of the Study:

• To search for both promptlike and long-lived dark photons (A") produced in proton-proton collisions.
• To constrain the kinetic mixing strength between the photon and dark photon.
• To explore previously unsearched dark photon mass ranges.

Main Methods:

• Utilized a data sample from proton-proton collisions at 13 TeV center-of-mass energy, collected by the LHCb detector.
• Searched for A ightarrow ext{μ}^+ ext{μ}^- decays for both promptlike and long-lived scenarios.
• Applied statistical analysis to set 90% confidence-level exclusion limits.

Main Results:

• No significant evidence for dark photon signals was observed in either search.
• The promptlike A extprime search established the most stringent constraints to date for dark photons in specific mass intervals (214
• The search for long-lived A extprime decays set world-leading constraints on low-mass dark photons with lifetimes around 1 ps.

Conclusions:

• The absence of a signal places constraints on the existence and properties of dark photons.
• This study advances the search for new physics beyond the Standard Model.
• The results provide valuable input for future dark matter and particle physics research.