CP Violation In The Standard Model Quantified And More

There are two components of the Standard Model of Particle Physics that violate charge parity (CP) conversation, which is to say that the laws of physics are asymmetric between interactions going forward in time and interactions going backward in time. One is the CP violation parameter of the four parameter CKM matrix, which is called beta (β), and applies to W boson mediated changes in quark flavor. The other is the CP violation parameter of the PMNS matrix which governs neutrino flavor oscillations, which has been measured only crudely but is very likely to be non-zero given current measurements to date.

A new measurement of the CKM matrix CP violation parameter using the decays of electromagnetically neutral B mesons has been made by the LHCb experiment  at the Large Hadron Collider (LHC). This is "the most precise single measurement of the CKM angle β to date and is more precise than the current world average." The status quo leading up to this new measurement was as follows:

Measurements of CP violation in neutral meson decays to charmonium final states have thus resulted in a high degree of precision for the angle β of the CKM matrix: sin(2β) = 0.699 ± 0.017. The first observation of CP violation in the B-meson system was reported in the B0→J/ψK0 S channel by the BaBar andBelle collaborations. The measurement of the CP-violation parameters in (2β) has been updated several times by these experiments, and more recently by the LHCb andBelleII collaborations.

The new paper, regrettably, doesn't actually report its measured value of β but does provide a formula to convert a parameter that it does measure to β. Assuming no beyond the Standard Model physics:

The parameter S can be related to the CKM angle β as S = sin(2β+∆ϕd+ . . . ). . . . Contributions from penguin topologies to the decay amplitude that cause an additional phase shift ∆ϕd are CKM suppressed, hence deviations of S from sin(2β) are expected to be small in the Standard Model.

The bottom line value, simultaneously fitting data from three different decay modes for S is S = 0.717 ± 0.013(stat) ± 0.008(syst).

Another new paper recaps the latest and greatest measurements of the masses of the five hadronizing Standard Model quarks and the strong force coupling constant: