Decoding (pseudo)-scalar operators in leptonic and semileptonic B decays.

Area of Science:

• High Energy Physics
• Particle Physics
• Beyond Standard Model Physics

Background:

• Leptonic and semileptonic B decays are crucial for probing New Physics (NP).
• Standard Model (SM) predictions for these decays can be modified by NP operators.
• Helicity suppression in SM amplitudes can be lifted by NP, offering new avenues for study.

Purpose of the Study:

• To present a strategy for determining short-distance coefficients of NP operators and the CKM element |V_ub|.
• To explore theoretically clean constraints and correlations between NP coefficients using leptonic decays.
• To obtain stronger bounds on NP contributions and extract |V_ub| by including semileptonic decays.

Main Methods:

• Analysis of leptonic B decays, particularly focusing on (pseudo-)scalar operators.
• Utilizing Belle collaboration data for the branching ratio of B -> Xsll.
• Incorporating semileptonic B decays and employing QCD sum rule and lattice calculations for hadronic form factors.

Main Results:

• Established theoretically clean constraints and correlations between NP coefficients for B -> Xsl+l- and B -> Xsl+l- decays.
• Investigated the impact of NP contributions on decay observables.
• Provided predictions for unmeasured decay observables.

Conclusions:

• The proposed strategy offers a robust framework for NP searches in B decays.
• Combining leptonic and semileptonic decays provides enhanced sensitivity to NP parameters.
• The study highlights the importance of CP-violating phases in NP coefficients.