First observation of the decay B(c)+ → J/ψπ(+) π- π+.

Area of Science:

• Particle Physics
• High-Energy Physics
• Hadron Spectroscopy

Background:

• The B(c) meson is a unique system containing two heavy quarks, c and b.
• Understanding its decays provides insights into the Standard Model and quantum chromodynamics.
• Previous studies have focused on other decay modes of the B(c) meson.

Purpose of the Study:

• To report the first observation of the B(c)(+) → J/ψπ(+) π(-) π(+) decay.
• To measure the ratio of branching fractions for this decay relative to a known mode.
• To compare experimental results with theoretical predictions for B(c) meson decays.

Main Methods:

• Analysis of 0.8 fb⁻¹ of proton-proton collision data collected at √s = 7 TeV.
• Utilizing the LHCb detector for particle identification and momentum measurement.
• Statistical analysis to establish the significance of the observed signal and measure branching fractions.

Main Results:

• First observation of the B(c)(+) → J/ψπ(+) π(-) π(+) decay.
• Measured branching fraction ratio B(B(c)(+) → J/ψπ(+) π(-) π(+))/B(B(c)(+)→J/ψπ⁺) = 2.41 ± 0.30 (stat) ± 0.33 (syst).
• Experimental findings are consistent with theoretical predictions.

Conclusions:

• The observation of this new decay mode enriches the B(c) meson decay landscape.
• The measured branching fraction ratio provides a valuable constraint for theoretical models.
• This result contributes to a more comprehensive understanding of heavy quarkonium physics.