Abstract
Recently the RBC-UKQCD lattice QCD collaboration presented new results for the hadronic matrix elements relevant for the ratio ε′/ε in the Standard Model (SM) albeit with significant uncertainties. With the present knowledge of the Wilson coefficients and isospin breaking effects there is still a sizable room left for new physics (NP) contributions to ε′/ε which could both enhance or suppress this ratio to agree with the data. The new SM value for the K0 − \( {\overline{K}}^0 \) mass difference ∆MK from RBC-UKQCD is on the other hand by 2σ above the data hinting for NP required to suppress ∆MK. Simultaneously the most recent results for K+ → \( {\pi}^{+}\nu \overline{\nu} \) from NA62 and for KL → \( {\pi}^0\nu \overline{\nu} \) from KOTO still allow for significant NP contributions. We point out that the suppression of ∆MK by NP requires the presence of new CP-violating phases with interesting implications for K → \( \pi \nu \overline{\nu} \), KS → μ+μ− and KL → π0ℓ+ℓ− decays. Considering a Z′-scenario within the SMEFT we analyze the dependence of all these observables on the size of NP still allowed by the data on ε′/ε. The hinted ∆MK anomaly together with the εK constraint implies in the presence of only left-handed (LH) or right-handed (RH) flavour-violating Z′ couplings strict correlation between K+ → \( {\pi}^{+}\nu \overline{\nu} \) and KL → \( {\pi}^0\nu \overline{\nu} \) branching ratios so that they are either simultaneously enhanced or suppressed relative to SM predictions. An anticorrelation can only be obtained in the presence of both LH and RH couplings. Interestingly, the NP QCD penguin scenario for ε′/ε is excluded by SMEFT renormalization group effects in εK so that NP effects in ε′/ε are governed by electroweak penguins. We also investigate for the first time whether the presence of a heavy Z′ with flavour violating couplings could generate through top Yukawa renormalization group effects FCNCs mediated by the SM Z-boson. The outcome turns out to be very interesting.
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References
A.J. Buras and J. Girrbach, Towards the Identification of New Physics through Quark Flavour Violating Processes, Rept. Prog. Phys. 77 (2014) 086201 [arXiv:1306.3775] [INSPIRE].
A.J. Buras, Gauge Theory of Weak Decays, Cambridge University Press, Cambridge U.K. (2020).
M.K. Gaillard and B.W. Lee, Rare Decay Modes of the K-Mesons in Gauge Theories, Phys. Rev. D 10 (1974) 897 [INSPIRE].
Z. Bai, N.H. Christ, T. Izubuchi, C.T. Sachrajda, A. Soni and J. Yu, KL − KS Mass Difference from Lattice QCD, Phys. Rev. Lett. 113 (2014) 112003 [arXiv:1406.0916] [INSPIRE].
N.H. Christ, X. Feng, G. Martinelli and C.T. Sachrajda, Effects of finite volume on the KL –KS mass difference, Phys. Rev. D 91 (2015) 114510 [arXiv:1504.01170] [INSPIRE].
Z. Bai, N.H. Christ and C.T. Sachrajda, The KL –KS Mass Difference, EPJ Web Conf. 175 (2018) 13017 [INSPIRE].
J.M. Gerard, W. Grimus, A. Raychaudhuri and G. Zoupanos, Super Kobayashi-Maskawa CP-violation, Phys. Lett. B 140 (1984) 349 [INSPIRE].
F. Gabbiani, E. Gabrielli, A. Masiero and L. Silvestrini, A Complete analysis of FCNC and CP constraints in general SUSY extensions of the standard model, Nucl. Phys. B 477 (1996) 321 [hep-ph/9604387] [INSPIRE].
UTfit collaboration, Model-independent constraints on ∆F = 2 operators and the scale of new physics, JHEP 03 (2008) 049 [arXiv:0707.0636] [INSPIRE].
G. Isidori, Y. Nir and G. Perez, Flavor Physics Constraints for Physics Beyond the Standard Model, Ann. Rev. Nucl. Part. Sci. 60 (2010) 355 [arXiv:1002.0900] [INSPIRE].
L. Silvestrini and M. Valli, Model-independent Bounds on the Standard Model Effective Theory from Flavour Physics, Phys. Lett. B 799 (2019) 135062 [arXiv:1812.10913] [INSPIRE].
L. Calibbi, A. Crivellin, F. Kirk, C.A. Manzari and L. Vernazza, Z′ models with less-minimal flavour violation, Phys. Rev. D 101 (2020) 095003 [arXiv:1910.00014] [INSPIRE].
A.J. Buras, New physics patterns in ε′/ε and εK with implications for rare kaon decays and ∆MK , JHEP 04 (2016) 071 [arXiv:1601.00005] [INSPIRE].
RBC, UKQCD collaboration, Direct CP-violation and the ∆I = 1/2 rule in K → ππ decay from the standard model, Phys. Rev. D 102 (2020) 054509 [arXiv:2004.09440] [INSPIRE].
J. Aebischer, C. Bobeth and A.J. Buras, On the importance of NNLO QCD and isospin-breaking corrections in ε′/ε, Eur. Phys. J. C 80 (2020) 1 [arXiv:1909.05610] [INSPIRE].
A.J. Buras and J.-M. Gérard, Isospin-breaking in ε′/ε: impact of η0 at the dawn of the 2020s, Eur. Phys. J. C 80 (2020) 701 [arXiv:2005.08976] [INSPIRE].
A.J. Buras, P. Gambino and U.A. Haisch, Electroweak penguin contributions to nonleptonic ∆F = 1 decays at NNLO, Nucl. Phys. B 570 (2000) 117 [hep-ph/9911250] [INSPIRE].
J. Aebischer, C. Bobeth and A.J. Buras, ε′/ε in the Standard Model at the Dawn of the 2020s, Eur. Phys. J. C 80 (2020) 705 [arXiv:2005.05978] [INSPIRE].
V. Cirigliano, H. Gisbert, A. Pich and A. Rodríguez-Sánchez, Isospin-violating contributions to ϵ′/ϵ, JHEP 02 (2020) 032 [arXiv:1911.01359] [INSPIRE].
NA48 collaboration, A Precision measurement of direct CP-violation in the decay of neutral kaons into two pions, Phys. Lett. B 544 (2002) 97 [hep-ex/0208009] [INSPIRE].
KTeV collaboration, Measurements of direct CP-violation, CPT symmetry, and other parameters in the neutral kaon system, Phys. Rev. D 67 (2003) 012005 [Erratum ibid. 70 (2004) 079904] [hep-ex/0208007] [INSPIRE].
KTeV collaboration, The Final Measurement of ε′/ε from KTeV, in Heavy Quarks and Leptons 2008 (HQ&L08), 9, 2009 [arXiv:0909.2555] [INSPIRE].
M. Blanke, Insights from the Interplay of K → \( \pi \nu \overline{\nu} \) and EK on the New Physics Flavour Structure, Acta Phys. Polon. B 41 (2010) 127 [arXiv:0904.2528] [INSPIRE].
NA62 collaboration, An investigation of the very rare K+ → \( {\pi}^{+}\nu \overline{\nu} \) decay, JHEP 11 (2020) 042 [arXiv:2007.08218] [INSPIRE].
R. Marchevski, New result on the search for the K+ → \( {\pi}^{+}\nu \overline{\nu} \) decay at the NA62 experiment at CERN, at 40th International Conference on High Energy Physics (ICHEP), Prague Czech Republic (2020).
KOTO collaboration, Search for the KL → \( {\pi}^0\nu \overline{\nu} \) and KL → π0X0 decays at the J-PARC KOTO experiment, Phys. Rev. Lett. 122 (2019) 021802 [arXiv:1810.09655] [INSPIRE].
A.J. Buras, D. Buttazzo, J. Girrbach-Noe and R. Knegjens, K+ → \( {\pi}^{+}\nu \overline{\nu} \) and KL → \( {\pi}^0\nu \overline{\nu} \) in the Standard Model: status and perspectives, JHEP 11 (2015) 033 [arXiv:1503.02693] [INSPIRE].
C. Bobeth, A.J. Buras, A. Celis and M. Jung, Patterns of Flavour Violation in Models with Vector-Like Quarks, JHEP 04 (2017) 079 [arXiv:1609.04783] [INSPIRE].
S. Shinohara, Search for the rare decay KL → \( {\pi}^0\nu \overline{\nu} \) at J-PARC KOTO experiment, at International Conference on Kaon Physics (KAON2019), Perugia Italy (2019).
T. Kitahara, T. Okui, G. Perez, Y. Soreq and K. Tobioka, New physics implications of recent search for KL → \( {\pi}^0\nu \overline{\nu} \) at KOTO, Phys. Rev. Lett. 124 (2020) 071801 [arXiv:1909.11111] [INSPIRE].
X.-G. He, X.-D. Ma, J. Tandean and G. Valencia, Evading the Grossman-Nir bound with ∆I = 3/2 new physics, JHEP 08 (2020) 034 [arXiv:2005.02942] [INSPIRE].
X.-G. He, X.-D. Ma, J. Tandean and G. Valencia, Breaking the Grossman-Nir Bound in Kaon Decays, JHEP 04 (2020) 057 [arXiv:2002.05467] [INSPIRE].
K. Fuyuto, W.-S. Hou and M. Kohda, Loophole in K → \( \pi \nu \overline{\nu} \) Search and New Weak Leptonic Forces, Phys. Rev. Lett. 114 (2015) 171802 [arXiv:1412.4397] [INSPIRE].
A.J. Buras, D. Buttazzo and R. Knegjens, K → \( \pi \nu \overline{\nu} \) and ε′/ε in simplified new physics models, JHEP 11 (2015) 166 [arXiv:1507.08672] [INSPIRE].
A.J. Buras and R. Fleischer, Bounds on the unitarity triangle, sin 2β and K → \( \pi \nu \overline{\nu} \) decays in models with minimal flavor violation, Phys. Rev. D 64 (2001) 115010 [hep-ph/0104238] [INSPIRE].
M. Blanke and A.J. Buras, Lower bounds on ∆Ms,d from constrained minimal flavour violation, JHEP 05 (2007) 061 [hep-ph/0610037] [INSPIRE].
M. Blanke and A.J. Buras, Universal Unitarity Triangle 2016 and the tension between ∆Ms,d and εK in CMFV models, Eur. Phys. J. C 76 (2016) 197 [arXiv:1602.04020] [INSPIRE].
C. Bobeth, A.J. Buras, A. Celis and M. Jung, Yukawa enhancement of Z -mediated new physics in ∆S = 2 and ∆B = 2 processes, JHEP 07 (2017) 124 [arXiv:1703.04753] [INSPIRE].
M. Endo, T. Kitahara and D. Ueda, SMEFT top-quark effects on ∆F = 2 observables, JHEP 07 (2019) 182 [arXiv:1811.04961] [INSPIRE].
P. Langacker, The Physics of Heavy Z′ Gauge Bosons, Rev. Mod. Phys. 81 (2009) 1199 [arXiv:0801.1345] [INSPIRE].
A.J. Buras, F. De Fazio and J. Girrbach, The Anatomy of Z′ and Z with Flavour Changing Neutral Currents in the Flavour Precision Era, JHEP 02 (2013) 116 [arXiv:1211.1896] [INSPIRE].
A.J. Buras, F. De Fazio, J. Girrbach and M.V. Carlucci, The Anatomy of Quark Flavour Observables in 331 Models in the Flavour Precision Era, JHEP 02 (2013) 023 [arXiv:1211.1237] [INSPIRE].
UTfit collaboration, The Unitarity Triangle Fit in the Standard Model and Hadronic Parameters from Lattice QCD: A Reappraisal after the Measurements of ∆ms and BR(B → τντ), JHEP 10 (2006) 081 [hep-ph/0606167] [INSPIRE].
J. Charles et al., Current status of the Standard Model CKM fit and constraints on ∆F = 2 New Physics, Phys. Rev. D 91 (2015) 073007 [arXiv:1501.05013] [INSPIRE].
J. Brod, M. Gorbahn and E. Stamou, Standard-Model Prediction of ϵK with Manifest Quark-Mixing Unitarity, Phys. Rev. Lett. 125 (2020) 171803 [arXiv:1911.06822] [INSPIRE].
B. Grzadkowski, M. Iskrzynski, M. Misiak and J. Rosiek, Dimension-Six Terms in the Standard Model Lagrangian, JHEP 10 (2010) 085 [arXiv:1008.4884] [INSPIRE].
J. de Blas, J.C. Criado, M. Pérez-Victoria and J. Santiago, Effective description of general extensions of the Standard Model: the complete tree-level dictionary, JHEP 03 (2018) 109 [arXiv:1711.10391] [INSPIRE].
J. Aebischer et al., WCxf: an exchange format for Wilson coefficients beyond the Standard Model, Comput. Phys. Commun. 232 (2018) 71 [arXiv:1712.05298] [INSPIRE].
J. Aebischer, A. Crivellin, M. Fael and C. Greub, Matching of gauge invariant dimension-six operators for b → s and b → c transitions, JHEP 05 (2016) 037 [arXiv:1512.02830] [INSPIRE].
J. Aebischer, J. Kumar and D.M. Straub, Wilson: a Python package for the running and matching of Wilson coefficients above and below the electroweak scale, Eur. Phys. J. C 78 (2018) 1026 [arXiv:1804.05033] [INSPIRE].
W.H. Press, S.A. Teukolsky, W.T. Vetterling and B.P. Flannery, Numerical Recipes 3rd Edition: The Art of Scientific Computing, third edition Cambridge University Press, Cambridge U.S.A. (2007).
J. Aebischer and J. Kumar, Flavour violating effects of Yukawa running in SMEFT, JHEP 09 (2020) 187 [arXiv:2005.12283] [INSPIRE].
R. Coy, M. Frigerio, F. Mescia and O. Sumensari, New physics in b → sRR transitions at one loop, Eur. Phys. J. C 80 (2020) 52 [arXiv:1909.08567] [INSPIRE].
S. Matsuzaki, K. Nishiwaki and R. Watanabe, Phenomenology of flavorful composite vector bosons in light of B anomalies, JHEP 08 (2017) 145 [arXiv:1706.01463] [INSPIRE].
N. Assad, B. Fornal and B. Grinstein, Baryon number and lepton universality violation in leptoquark and diquark models, Phys. Lett. B 777 (2018) 324 [arXiv:1708.06350] [INSPIRE].
L. Di Luzio, A. Greljo and M. Nardecchia, Gauge leptoquark as the origin of B-physics anomalies, Phys. Rev. D 96 (2017) 115011 [arXiv:1708.08450] [INSPIRE].
M. Bordone, C. Cornella, J. Fuentes-Martin and G. Isidori, A three-site gauge model for flavor hierarchies and flavor anomalies, Phys. Lett. B 779 (2018) 317 [arXiv:1712.01368] [INSPIRE].
L. Di Luzio, J. Fuentes-Martin, A. Greljo, M. Nardecchia and S. Renner, Maximal Flavour Violation: a Cabibbo mechanism for leptoquarks, JHEP 11 (2018) 081 [arXiv:1808.00942] [INSPIRE].
A. Dedes, W. Materkowska, M. Paraskevas, J. Rosiek and K. Suxho, Feynman rules for the Standard Model Effective Field Theory in Rξ-gauges, JHEP 06 (2017) 143 [arXiv:1704.03888] [INSPIRE].
CMS collaboration, Search for a narrow resonance in high-mass dilepton final states in proton-proton collisions using 140 fb−1 of data at \( \sqrt{s} \) = 13 TeV, CMS-PAS-EXO-19-019 (2019).
ATLAS collaboration, Search for high-mass dilepton resonances using 139 fb−1 of pp collision data collected at \( \sqrt{s} \) = 13 TeV with the ATLAS detector, Phys. Lett. B 796 (2019) 68 [arXiv:1903.06248] [INSPIRE].
E. Accomando, A. Belyaev, L. Fedeli, S.F. King and C. Shepherd-Themistocleous, Z’ physics with early LHC data, Phys. Rev. D 83 (2011) 075012 [arXiv:1010.6058] [INSPIRE].
A.J. Buras, F. De Fazio and J. Girrbach, ∆I = 1/2 rule, ε′/ε and K → \( \pi \nu \overline{\nu} \) in Z′(Z) and G′ models with FCNC quark couplings, Eur. Phys. J. C 74 (2014) 2950 [arXiv:1404.3824] [INSPIRE].
A.J. Buras, D. Buttazzo, J. Girrbach-Noe and R. Knegjens, Can we reach the Zeptouniverse with rare K and Bs,d decays?, JHEP 11 (2014) 121 [arXiv:1408.0728] [INSPIRE].
J. Aebischer, A.J. Buras, M. Cerdà-Sevilla and F. De Fazio, Quark-lepton connections in Z’ mediated FCNC processes: gauge anomaly cancellations at work, JHEP 02 (2020) 183 [arXiv:1912.09308] [INSPIRE].
R. Alonso, A. Carmona, B.M. Dillon, J.F. Kamenik, J. Martin Camalich and J. Zupan, A clockwork solution to the flavor puzzle, JHEP 10 (2018) 099 [arXiv:1807.09792] [INSPIRE].
A. Smolkovič, M. Tammaro and J. Zupan, Anomaly free Froggatt-Nielsen models of flavor, JHEP 10 (2019) 188 [arXiv:1907.10063] [INSPIRE].
W. Altmannshofer, J. Davighi and M. Nardecchia, Gauging the accidental symmetries of the standard model, and implications for the flavor anomalies, Phys. Rev. D 101 (2020) 015004 [arXiv:1909.02021] [INSPIRE].
G. D’Amico et al., Flavour anomalies after the \( {R}_{K^{\ast }} \) measurement, JHEP 09 (2017) 010 [arXiv:1704.05438] [INSPIRE].
E.E. Jenkins, A.V. Manohar and M. Trott, Renormalization Group Evolution of the Standard Model Dimension Six Operators I: Formalism and lambda Dependence, JHEP 10 (2013) 087 [arXiv:1308.2627] [INSPIRE].
E.E. Jenkins, A.V. Manohar and M. Trott, Renormalization Group Evolution of the Standard Model Dimension Six Operators II: Yukawa Dependence, JHEP 01 (2014) 035 [arXiv:1310.4838] [INSPIRE].
R. Alonso, E.E. Jenkins, A.V. Manohar and M. Trott, Renormalization Group Evolution of the Standard Model Dimension Six Operators III: Gauge Coupling Dependence and Phenomenology, JHEP 04 (2014) 159 [arXiv:1312.2014] [INSPIRE].
J. Aebischer, C. Bobeth, A.J. Buras and D.M. Straub, Anatomy of ε′/ε beyond the standard model, Eur. Phys. J. C 79 (2019) 219 [arXiv:1808.00466] [INSPIRE].
A. Celis, J. Fuentes-Martin, A. Vicente and J. Virto, DsixTools: The Standard Model Effective Field Theory Toolkit, Eur. Phys. J. C 77 (2017) 405 [arXiv:1704.04504] [INSPIRE].
J. Aebischer, A.J. Buras and J.-M. Gérard, BSM hadronic matrix elements for ϵ′/ϵ and K → ππ decays in the Dual QCD approach, JHEP 02 (2019) 021 [arXiv:1807.01709] [INSPIRE].
J. Aebischer, C. Bobeth, A.J. Buras, J.-M. Gérard and D.M. Straub, Master formula for ε′/ε beyond the Standard Model, Phys. Lett. B 792 (2019) 465 [arXiv:1807.02520] [INSPIRE].
R. Alonso, B. Grinstein and J. Martin Camalich, SU(2) × U(1) gauge invariance and the shape of new physics in rare B decays, Phys. Rev. Lett. 113 (2014) 241802 [arXiv:1407.7044] [INSPIRE].
G. Buchalla, A.J. Buras and M.K. Harlander, Penguin box expansion: Flavor changing neutral current processes and a heavy top quark, Nucl. Phys. B 349 (1991) 1 [INSPIRE].
A.J. Buras, J. Girrbach-Noe, C. Niehoff and D.M. Straub, B → \( {K}^{\left(\ast \right)}\nu \overline{\nu} \) decays in the Standard Model and beyond, JHEP 02 (2015) 184 [arXiv:1409.4557] [INSPIRE].
G. Isidori and R. Unterdorfer, On the short distance constraints from KL,S → μ+μ−, JHEP 01 (2004) 009 [hep-ph/0311084] [INSPIRE].
G. D’Ambrosio and T. Kitahara, Direct C P Violation in K → μ+μ−, Phys. Rev. Lett. 119 (2017) 201802 [arXiv:1707.06999] [INSPIRE].
F. Mescia, C. Smith and S. Trine, KL → π0e+e− and KL → π0μ+μ−: A binary star on the stage of flavor physics, JHEP 08 (2006) 088 [hep-ph/0606081] [INSPIRE].
KTeV collaboration, Search for the rare decay KL → π0e+e−, Phys. Rev. Lett. 93 (2004) 021805 [hep-ex/0309072] [INSPIRE].
KTEV collaboration, Search for the Decay KL → π0μ+μ−, Phys. Rev. Lett. 84 (2000) 5279 [hep-ex/0001006] [INSPIRE].
LHCb collaboration, Improved limit on the branching fraction of the rare decay \( {K}_{\mathrm{S}}^0 \) → μ+ μ−, Eur. Phys. J. C 77 (2017) 678 [arXiv:1706.00758] [INSPIRE].
Y. Grossman and Y. Nir, KL → \( {\pi}^0\nu \overline{\nu} \) beyond the standard model, Phys. Lett. B 398 (1997) 163 [hep-ph/9701313] [INSPIRE].
J. Aebischer, M. Fael, C. Greub and J. Virto, B physics Beyond the Standard Model at One Loop: Complete Renormalization Group Evolution below the Electroweak Scale, JHEP 09 (2017) 158 [arXiv:1704.06639] [INSPIRE].
E.E. Jenkins, A.V. Manohar and P. Stoffer, Low-Energy Effective Field Theory below the Electroweak Scale: Anomalous Dimensions, JHEP 01 (2018) 084 [arXiv:1711.05270] [INSPIRE].
M.E. Machacek and M.T. Vaughn, Two Loop Renormalization Group Equations in a General Quantum Field Theory. 2. Yukawa Couplings, Nucl. Phys. B 236 (1984) 221 [INSPIRE].
Y. Nir and M.P. Worah, Probing the flavor and CP structure of supersymmetric models with K → \( \pi \nu \overline{\nu} \) decays, Phys. Lett. B 423 (1998) 319 [hep-ph/9711215] [INSPIRE].
A.J. Buras, A. Romanino and L. Silvestrini, K → \( \pi \nu \overline{\nu} \): A Model independent analysis and supersymmetry, Nucl. Phys. B 520 (1998) 3 [hep-ph/9712398] [INSPIRE].
A.J. Buras, G. Colangelo, G. Isidori, A. Romanino and L. Silvestrini, Connections between ϵ′/ϵ and rare kaon decays in supersymmetry, Nucl. Phys. B 566 (2000) 3 [hep-ph/9908371] [INSPIRE].
A.J. Buras, T. Ewerth, S. Jager and J. Rosiek, K+ → \( {\pi}^{+}\nu \overline{\nu} \) and KL → \( {\pi}^0\nu \overline{\nu} \) decays in the general MSSM, Nucl. Phys. B 714 (2005) 103 [hep-ph/0408142] [INSPIRE].
G. Isidori, F. Mescia, P. Paradisi, C. Smith and S. Trine, Exploring the flavour structure of the MSSM with rare K decays, JHEP 08 (2006) 064 [hep-ph/0604074] [INSPIRE].
M. Blanke, A.J. Buras, B. Duling, K. Gemmler and S. Gori, Rare K and B Decays in a Warped Extra Dimension with Custodial Protection, JHEP 03 (2009) 108 [arXiv:0812.3803] [INSPIRE].
M. Bauer, S. Casagrande, U. Haisch and M. Neubert, Flavor Physics in the Randall-Sundrum Model: II. Tree-Level Weak-Interaction Processes, JHEP 09 (2010) 017 [arXiv:0912.1625] [INSPIRE].
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Aebischer, J., Buras, A.J. & Kumar, J. Another SMEFT story: Z′ facing new results on ε′/ε, ∆MK and K → \( \pi \nu \overline{\nu} \). J. High Energ. Phys. 2020, 97 (2020). https://doi.org/10.1007/JHEP12(2020)097
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DOI: https://doi.org/10.1007/JHEP12(2020)097