Evidence for a B_{s}^{0}π^{±} State

Area of Science:

• High Energy Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• The Standard Model of particle physics describes fundamental particles and forces.
• Exotic hadrons, such as tetraquarks, challenge existing theoretical frameworks.
• Understanding the composition of hadrons provides insights into the strong nuclear force.

Purpose of the Study:

• To search for and characterize new hadronic states.
• To investigate the existence of tetraquarks with four different valence quark flavors.
• To measure the mass and width of the observed structure X(5568).

Main Methods:

• Analysis of proton-antiproton collision data collected by the D0 experiment at the Fermilab Tevatron.
• Reconstruction of the decay sequence X(5568)→B_{s}^{0}π^{±}, with B_{s}^{0}→J/ψϕ and J/ψ→μ^{+}μ^{-}, ϕ→K^{+}K^{-}.
• Statistical analysis to establish evidence for the narrow structure X(5568).

Main Results:

• Evidence for a narrow structure, X(5568), was observed in the specified decay channel.
• The measured mass of X(5568) is 5567.8±2.9(stat)_{-1.9}^{+0.9} MeV/c².
• The measured natural width is 21.9±6.4(stat)_{-2.5}^{+5.0} MeV/c², indicating a potentially new type of tetraquark state.

Conclusions:

• The observation of X(5568) provides the first evidence for a hadronic state with valence quarks of four different flavors.
• This finding could represent a new class of exotic hadrons, expanding our understanding of QCD.
• Further theoretical and experimental studies are needed to confirm the nature and properties of X(5568).