NNLO QCD Contributions to $\varepsilon ^\prime /\varepsilon $

Cerdà-Sevilla, M.

doi:10.5506/aphyspolb.49.1087

Cited by 39 publications

(18 citation statements)

References 19 publications

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“…• The preliminary result on NNLO QCD corrections to QCDP contributions [19,20] demonstrates significant reduction of various scale uncertainties, foremost of µ c , and indicates an additional modest suppression of ε /ε.…”

Section: Introductionmentioning

confidence: 86%

“…in the large-N limit. The dimensionful parameters entering (7), (8) have been calculated at µ = m c using [40] m K = 497.614 MeV, F π = 130.41 (20) MeV,…”

Section: The Parameters Bmentioning

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%

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

2019

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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: Introductionmentioning

confidence: 86%

“…in the large-N limit. The dimensionful parameters entering (7), (8) have been calculated at µ = m c using [40] m K = 497.614 MeV, F π = 130.41 (20) MeV,…”

Section: The Parameters Bmentioning

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 3 more Smart Citations

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

2019

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General non-leptonic ∆F = 1 WET at the NLO in QCD

Aebischer

Bobeth

Buras

et al. 2021

J. High Energ. Phys.

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We reconsider the complete set of four-quark operators in the Weak Effective Theory (WET) for non-leptonic ∆F = 1 decays that govern s → d and b → d, s transitions in the Standard Model (SM) and beyond, at the Next-to-Leading Order (NLO) in QCD. We discuss cases with different numbers Nf of active flavours, intermediate threshold corrections, as well as the issue of transformations between operator bases beyond leading order to facilitate the matching to high-energy completions or the Standard Model Effective Field Theory (SMEFT) at the electroweak scale. As a first step towards a SMEFT NLO analysis of K → ππ and non-leptonic B-meson decays, we calculate the relevant WET Wilson coefficients including two-loop contributions to their renormalization group running, and express them in terms of the Wilson coefficients in a particular operator basis for which the one-loop matching to SMEFT is already known.

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Gauge Theories of Weak Decays

Buras

2020

116

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We have mentioned already at the beginning of the book that the fundamental role in elementary particle physics, that is, the SM and its extensions, is played by Lagrangians. They encode the information about the particle content of a given theory and of fundamental interactions between these particles that are characteristic for this theory. Therefore, it is essential to start our presentation by discussing the general structure of various Lagrangians that we will encounter in this book.The theories we will discuss are relativistic quantum field theories, and it would appear at first sight that this first step of our expedition is extremely difficult. Yet, the seminal observation of Feynman that a given classical theory can be quantized by means of the path integral method simplifies things significantly. We can formulate the quantum field theory with the help of a Lagrangian of a classical field theory without introducing operators as done in canonical quantization. Having it, a simple set of steps allows us to derive the so-called Feynman rules and use them to calculate the implications of a given theory for various observables that can be compared with experiment.A very important role in particle physics is played by symmetries. They increase significantly the predictive power of a given theory, in particular by reducing the number of free parameters. In this context a very good example is quantum chromodynamics (QCD), the theory of strong interactions. With eight gluons and three colors for quarks, there is a multitude of interactions that, without the SU(3) symmetry governing them, could be rather arbitrary. But the SU(3) symmetry implies certain conservation laws, and at the end there is only a single parameter in QCD: the value of the strong coupling evaluated at some energy scale that can be determined in experiment. Once this is done, all effects of strong interactions can be uniquely predicted, even if this requires often very difficult calculations.The case of QCD is however special as it is based on an exact nonabelian symmetry. We will be more specific about this terminology later. In quantum electrodynamics (QED), which is based on an exact abelian symmetry U(1), in addition to the value of the electromagnetic coupling also the electric charges of quarks and leptons and generally fermions, scalars, and vector particles in a given theory are free. They have to be determined in experiment. In QCD all color charges are fixed by the SU(3) symmetry.Yet QED, similar to QCD, is a very predictive theory because it is based on an exact symmetry. This is generally not the case in nature, and on many occasions the symmetries that we encounter in particle physics are only approximate, and the manner in which 25

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NNLO QCD Contributions to $\varepsilon ^\prime /\varepsilon $

Cited by 39 publications

References 19 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 $$\varepsilon '/\varepsilon $$

General non-leptonic ∆F = 1 WET at the NLO in QCD

Gauge Theories of Weak Decays

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