First Experimental Study of Photon Polarization in Radiative B_{s}^{0} Decays

Area of Science:

• High Energy Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• Radiative B_{s}^{0} decays offer a unique probe into the Standard Model.
• Understanding photon polarization in these decays is crucial for testing fundamental physics.
• Previous studies lacked direct measurements of this polarization parameter.

Purpose of the Study:

• To measure the polarization of photons in radiative B_{s}^{0} decays for the first time.
• To determine the parameter A^{Δ}, sensitive to New Physics beyond the Standard Model.
• To compare experimental results with Standard Model predictions.

Main Methods:

• Utilized data from proton-proton collisions recorded by the LHCb experiment.
• Analyzed an integrated luminosity of 3 fb^{-1} at 7 and 8 TeV center-of-mass energies.
• Performed a time-dependent analysis of the B_{s}^{0}→ϕγ decay rate.

Main Results:

• Measured the parameter A^{Δ} = -0.98_{-0.52}^{+0.46}_{-0.20}^{+0.23}.
• This is the first measurement of photon polarization in radiative B_{s}^{0} decays.
• The result is consistent with the Standard Model prediction within 2 standard deviations.

Conclusions:

• The first measurement of photon polarization in radiative B_{s}^{0} decays is reported.
• The obtained value of A^{Δ} supports the validity of the Standard Model.
• This study opens new avenues for searching for New Physics in flavor-changing neutral currents.