Measurement of the Λ_{b}^{0}→Λ(1520)μ^{+}μ^{-} Differential Branching Fraction

Area of Science:

• Particle Physics
• High-Energy Physics
• Hadron Spectroscopy

Background:

• Rare decays of beauty baryons provide sensitive probes of New Physics.
• Previous measurements of rare decays have shown tensions with the Standard Model.
• The decay Lambda_b^0 -> Lambda(1520)mu+mu- is sensitive to contributions from New Physics.

Purpose of the Study:

• To measure the branching fraction of the rare decay Lambda_b^0 -> Lambda(1520)mu+mu- for the first time.
• To test the Standard Model predictions for this decay.
• To search for potential signs of New Physics.

Main Methods:

• Analysis of a large dataset collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV.
• Selection of candidate Lambda_b^0 -> Lambda(1520)mu+mu- decays using specific kinematic criteria.
• Measurement of the branching fraction in different intervals of the dimuon invariant mass squared (q^2), excluding charmonium resonances.

Main Results:

• The branching fraction of the Lambda_b^0 -> Lambda(1520)mu+mu- decay is measured for the first time.
• The measured branching fraction in the highest q^2 interval (q^2 > 15.0 GeV^2/c^4) agrees with the Standard Model predictions.
• This agreement provides valuable constraints on theoretical models and potential New Physics contributions.

Conclusions:

• The first measurement of the Lambda_b^0 -> Lambda(1520)mu+mu- branching fraction is reported.
• The results are consistent with the Standard Model in the region with minimal theoretical uncertainties.
• This study contributes to the ongoing effort to precisely probe the Standard Model and search for New Physics in rare B-hadron decays.