Updated evaluation of 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>ϵ</mml:mi></mml:mrow><mml:mrow><mml:mi>K</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>
 in the standard model with lattice QCD inputs

We review lattice results related to pion, kaon, D-meson, B-meson, and nucleon physics with the aim of making them easily accessible to the nuclear and particle physics communities. More specifically, we report on the determination of the light-quark masses, the form factor $$f_+(0)$$f+(0) arising in the semileptonic $$K \rightarrow \pi $$K→π transition at zero momentum transfer, as well as the decay constant ratio $$f_K/f_\pi $$fK/fπ and its consequences for the CKM matrix elements $$V_{us}$$Vus and $$V_{ud}$$Vud. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of $$SU(2)_L\times SU(2)_R$$SU(2)L×SU(2)R and $$SU(3)_L\times SU(3)_R$$SU(3)L×SU(3)R Chiral Perturbation Theory. We review the determination of the $$B_K$$BK parameter of neutral kaon mixing as well as the additional four B parameters that arise in theories of physics beyond the Standard Model. For the heavy-quark sector, we provide results for $$m_c$$mc and $$m_b$$mb as well as those for D- and B-meson decay constants, form factors, and mixing parameters. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. We review the status of lattice determinations of the strong coupling constant $$\alpha _s$$αs. Finally, in this review we have added a new section reviewing results for nucleon matrix elements of the axial, scalar and tensor bilinears, both isovector and flavor diagonal.

show abstract

“…The present uncertainty on |V cb | has a significant impact on the error of K (see, e.g., Ref. [484] and a recent update [485]).…”

Section: Indirect Cp Violation and K In The Smmentioning

confidence: 99%

FLAG Review 2019

et al. 2020

View full text Add to dashboard Cite

show abstract

“…It constrains one side of the unitarity triangle via the ratio jV ub j=jV cb j. It is also a dominant uncertainty in the determination of the CP-violation parameter ϵ K (where there is currently tension between the SM and experiment; see e.g., [42]).…”

Section: Introductionmentioning

confidence: 99%

Lattice QCD form factor for Bs→Ds*lν at zero recoil with nonperturbative current renormalization

et al. 2019

View full text Add to dashboard Cite

We present details of a lattice QCD calculation of the B s → D Ã s axial form factor at zero recoil using the highly improved staggered quark (HISQ) formalism on the second-generation MILC gluon ensembles that include up, down, strange and charm quarks in the sea. Using the HISQ action for all valence quarks means that the lattice axial vector current that couples to the W can be renormalized fully nonperturbatively, giving a result free of the perturbative matching errors that previous lattice QCD calculations have had. We calculate correlation functions at three values of the lattice spacing, and multiple b-quark masses, for physical c and s. The functional dependence on the b-quark mass can be determined and compared to heavy quark effective theory expectations, and a result for the form factor obtained at the physical value of the b-quark mass. We find F B s →D Ã s ð1Þ ¼ h s A 1 ð1Þ ¼ 0.9020ð96Þ stat ð90Þ sys. This is in agreement with earlier lattice QCD results, which use NRQCD b quarks, with a total uncertainty reduced by more than a factor of 2. We discuss implications of this result for the B → D Ã axial form factor at zero recoil and for determinations of V cb .

show abstract

“…Finally we note that lowering |V cb | from the inclusive value used here softens the individual tensions in ∆M d and ∆M s , but has no impact on the discrepancy between the tree-level value of γ and ∆M d /∆M s , and in addition introduces a tension in the parameter ε K describing CP violation in neutral kaon mixing [7,10,27].…”

Section: Ckm Determinations and New Physics In Neutral B Meson Mixingmentioning

confidence: 73%

Constraints on New Physics from B Mesons

Blanke¹

2019

Proceedings of XXIX International Symposium on Lepton Photon Interactions at High Energies — PoS(LeptonPhoton2019)

View full text Add to dashboard Cite

Updated evaluation of ϵK in the standard model with lattice QCD inputs

Cited by 19 publications

References 71 publications

FLAG Review 2019

FLAG Review 2019

Lattice QCD form factor for Bs→Ds*lν at zero recoil with nonperturbative current renormalization

Constraints on New Physics from B Mesons

Contact Info

Product

Resources

About