Towards NNLO accuracy for ε′/ε

Cerdà-Sevilla, M.; Gorbahn, Martin; Jäger, Sebastian; Kokulu, Ahmet

doi:10.1088/1742-6596/800/1/012008

Cited by 33 publications

(68 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The error budget, discussed in Appendix B and summarized in Table 6, would imply the parametric theoretical error of 2.3 × 10 −4 . We increased it in order to take into account left-over scale uncertainties both in the EWP sector discussed here and in the QCDP sector analyzed at NNLO in [19,20]. But one should keep in mind that the central value in (15) will be shifted down by NNLO QCD corrections to QCDP by about 0.5×10 −4 as indicated in the preliminary plots in [19,20] without modifying the error in (15).…”

Section: Scale Uncertainties At Nlomentioning

confidence: 99%

“…The main goal of our paper is to illustrate how a future result from RBC-UKQCD would be affected by the inclusion of known isospin-breaking and QED corrections from [18] in point 2. and the NNLO QCD contributions to EWP in [34] in point 3. We also comment on the expected size of NNLO QCD contributions to QCDP from [19,20] in point 4. leaving a detailed analysis of them to these authors.…”

Section: Introductionmentioning

confidence: 98%

“…Use the NNLO QCD contributions to EWP in [34] in order to reduce the unphysical renormalization scheme and scale dependences.4. Include NNLO QCD contributions to QCDP from [19,20] in order to reduce left-over renormalization scale uncertainties.In view of the fact that meson evolution and the remaining three effects tend to suppress ε /ε, the expectation based on DQCD approach in [14] that ε /ε ≈ (5 ± 2) × 10 −4 in the SM could indeed be confirmed one day by LQCD.…”

mentioning

confidence: 99%

“…4. Include NNLO QCD contributions to QCDP from [19,20] in order to reduce left-over renormalization scale uncertainties.…”

mentioning

confidence: 99%

See 3 more Smart Citations

On the importance of NNLO QCD and isospin-breaking corrections in $$\varepsilon '/\varepsilon $$

2019

View full text Add to dashboard Cite

Following the 1999 analysis of Gambino, Haisch and one of us, we stress that all the recent NLO analyses of ε /ε in the Standard Model (SM) suffer from the renormalization scheme dependence present in the electroweak penguin contributions as well as from scale uncertainties in them related to the matching scale µ W and in particular to µ t in m t (µ t ). We also reemphasize the important role of isospin-breaking and QED effects in the evaluation of ε /ε. Omitting all these effects, as done in the 2015 analysis by RBC-UKQCD collaboration, and choosing as an example the QCD penguin (Q 6 ) and electroweak penguin (Q 8 ) parameters B(1/2) 6 and B(3/2) 8 to be B(1/2) 6 = 0.80 ± 0.08 and B(3/2) 8 2. Use the result for isospin-breaking and QED corrections from [18], which are compatible with the ones obtained already 30 years ago in [36].3. Use the NNLO QCD contributions to EWP in [34] in order to reduce the unphysical renormalization scheme and scale dependences.4. Include NNLO QCD contributions to QCDP from [19,20] in order to reduce left-over renormalization scale uncertainties.In view of the fact that meson evolution and the remaining three effects tend to suppress ε /ε, the expectation based on DQCD approach in [14] that ε /ε ≈ (5 ± 2) × 10 −4 in the SM could indeed be confirmed one day by LQCD.

show abstract

Section: Scale Uncertainties At Nlomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

mentioning

confidence: 99%

“…4. Include NNLO QCD contributions to QCDP from [19,20] in order to reduce left-over renormalization scale uncertainties.…”

mentioning

confidence: 99%

See 2 more Smart Citations

On the importance of NNLO QCD and isospin-breaking corrections in $$\varepsilon '/\varepsilon $$

2019

View full text Add to dashboard Cite

show abstract

“…The theoretically challenging next-to-next-to-leading order calculation is currently in progress [23].…”

Section: Pos(fpcp2017)042mentioning

confidence: 99%

Quo vadis flavour physics? FPCP2017 Theory Summary and Outlook

Blanke¹

2017

Proceedings of the 15th International Conference on Flavor Physics &Amp; CP Violation — PoS(FPCP2017)

View full text Add to dashboard Cite

We review the recent highlights of theoretical flavour physics, based on the theory summary talk given at FPCP2017. Over the past years, a number of intriguing anomalies have emerged in flavour violating K and B meson decays, constituting some of the most promising hints for the presence of physics beyond the Standard Model. We discuss the theory status of these anomalies and outline possible future directions to test the underlying New Physics. PoS(FPCP2017)042Quo vadis flavour physics? Monika Blanke New Physics sensitivity of flavour physicsDespite the impressive amount of data collected and analysed during run 1 and early run 2 of the LHC, until now no clear signal of new particles has been found in the direct searches for New Physics (NP). While we might have simply been unlucky in the choice of NP discovery modes, it is also conceivable that the NP scale is larger than the energies directly accessible at the LHC. Together with the continuing efforts at the high-p T frontier, it is therefore of utmost importance to explore alternative routes to access the nature of NP.Precision tests of Standard Model (SM) observables provide complementary access to NP contributions. As in such low energy processes new particles contribute via quantum effects, they are not plagued by the same strict energy cut-off as the LHC. The sensitivity in this case is limited by the cleanliness of the theoretical predictions in the SM, in addition to the obtained experimental precision. Particularly useful in this context are observables whose SM contribution is suppressed, increasing their potential NP sensitivity.Flavour and CP-violating observables hence play a key role in the hunt for NP. In the SM, flavour changing neutral current processes are strongly suppressed not only by a loop factor, but also by the smallness of the off-diagonal CKM elements and the GIM mechanism. NP contributions, even if generated well beyond the TeV scale, can therefore be significant, provided the theoretical and experiment precision is sufficient. The highest NP sensitivity is obtained in rare kaon decays due to their strong CKM suppression by V * ts V td and their theoretical cleanliness, in particular in the K → πνν decays. Indeed the latter have been shown to have the potential to probe NP scales beyond 1000 TeV [1]. B decays on the other hand, while being less sensitive to extremely high scales, have the advantage to offer a multitude of observables suitable to disentangle the underlying NP structure at work.In deciphering the NP flavour structure, the study of correlations between flavour and CPviolating observables will be a crucial task. In this context, we can distinguish between two different types of correlations:• Correlations between observables within a given meson system give information on the underlying NP operator structure. In this way, contributions from vector or scalar mediators can be distinguished, or the chirality of the NP coupling to the SM quarks and leptons can be determined.• Correlations between related observables in dif...

show abstract

BSM hadronic matrix elements for ε′/ε and K → ππ decays in the Dual QCD approach

Aebischer

Buras

Gérard

2019

J. High Energ. Phys.

View full text Add to dashboard Cite

We calculate for the first time all four-quark hadronic matrix elements of local operators possibly contributing to K → ππ decays and in particular to the ratio ε /ε beyond the Standard Model (BSM). To this end we use the Dual QCD (DQCD) approach. In addition to 7 new mirror operators obtained from the SM ones by flipping the chirality, we count 13 BSM four-quark operators of a given chirality linearly independent of each other and of the aforesaid 14 operators for which hadronic matrix elements are already known. We present results in two bases for all these operators, one termed DQCD basis useful for the calculation of the hadronic matrix elements in the DQCD approach and the other called SD basis suited to the short distance renormalization group evolution above the 1 GeV scale. We demonstrate that the pattern of long distance evolution (meson evolution) matches the one of short distance evolution (quark-gluon evolution), a property which to our knowledge cannot be presently achieved in any other analytical framework. The highlights of our paper are chirally enhanced matrix elements of tensor-tensor and scalar-scalar BSM operators. They could thereby explain the emerging ε /ε anomaly which is strongly indicated within DQCD with some support from lattice QCD. On the other hand we do not expect the BSM operators to be relevant for the ∆I = 1/2 rule.

show abstract

Towards NNLO accuracy for ε′/ε

Cited by 33 publications

References 29 publications

On the importance of NNLO QCD and isospin-breaking corrections in $$\varepsilon '/\varepsilon $$

On the importance of NNLO QCD and isospin-breaking corrections in $$\varepsilon '/\varepsilon $$

Quo vadis flavour physics? FPCP2017 Theory Summary and Outlook

BSM hadronic matrix elements for ε′/ε and K → ππ decays in the Dual QCD approach

Contact Info

Product

Resources

About