Abstract

The four general purpose detectors on the Tevatron (CDF, D0) and LHC (Atlas, CMS) hadron colliders continue to make important measurements in the field of CP violation (CPV) in B hadron physics. The CDF collaboration presents new results in direct CPV of charmless B decays, providing world-leading measurements in b baryon decays, and finding evidence for non zero CPV in the decay Bs 0 → K − π + . The D0 Collaboration presents measurements of the semileptonic mixing asymmetries in B 0 and Bs 0 mesons, with the former having a precision exceeding the previous world average. All four experiments perform time-dependent angular analysis of the decay Bs 0 → J /ψϕ enabling the extraction of the lifetime difference ΔΓs and the CPV phase ϕs J /ψϕ . In all cases, the results obtained are consistent with each other, and with the standard model predictions.

Highlights

  • The violation of CP symmetry (CPV) is one of the required ingredients of baryogenesis, through which the initial matter-antimatter symmetric state produced by the big bang evolved into the matter dominated universe we observe today

  • Measurements in the B meson sector are sensitive to any complex phases introduced in quark interactions, with several CP violation (CPV) observables having very small and precise predictions in the standard model (SM), but with large possible enhancements predicted by new physics models [3,4,5,6]

  • The presence of a non-zero complex phase in the CKM quark mixing matrix can lead to an asymmetry in the rate of neutral B mesons oscillating into their antiparticles, and to an asymmetry in the final state decay products following oscillation

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Summary

Introduction

The violation of CP symmetry (CPV) is one of the required ingredients of baryogenesis, through which the initial matter-antimatter symmetric state produced by the big bang evolved into the matter dominated universe we observe today. For a particular class of neutral meson decays, a single common final state can be reached with or without an intermediate B meson oscillation In such cases, the direct and oscillated processes interfere, and the overall complex phase driving CPV is the combination of the decay and mixing phases. Direct CP violation has been observed at greater than 5σ significance in the charmless decay B0 → K+π− This unexpected result can be accommodated, it is not strongly constrained, by the standard model, which predicts a similar effect in the corresponding charged mode B+ → K+π0.

Multibody B decays Combinatorial bkg
Signal Fit
The dilution factor
Standard Model
Findings
Summary
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