Constraints upon the CKM angle phi_2 (alpha) from Belle and BaBar

TL;DR

This paper reviews measurements from Belle and BaBar on B meson decays to constrain the CKM angle phi_2, indicating it is approximately 100 degrees, thus providing insights into CP violation in the quark sector.

Contribution

It compiles and analyzes experimental data from Belle and BaBar to derive constraints on the CKM angle phi_2, highlighting its value around 100 degrees.

Findings

phi_2 is approximately 100 degrees

Consistent measurements from multiple decay modes

Supports the Standard Model's CP violation framework

Abstract

The Belle and BaBar experiments have measured branching fractions and CP asymmetries in the charmless decay modes B0->pi+pi-, B0->rho+pi-/rho-pi+, and B0->rho+rho-. From these measurements, constraints upon the CKM angle phi_2 can be obtained. These constraints consistently indicate that phi_2 is around 100 degrees.