Abstract
We address the recent anomalies in semi-leptonic B-meson decays using a model of fermion masses based on the U(2) flavor symmetry. The new contributions to b → sℓℓ transitions arise due to a tree-level exchange of a Z′ vector boson gauging a U(1) subgroup of the flavor symmetry. They are controlled by a single parameter and are approximately aligned to the Standard Model prediction, with constructive interference in the e-channel and destructive interference in the μ-channel. The current experimental data on semi-leptonic B-meson decays can be very well reproduced without violating existing constraints from flavor violation in the quark and lepton sectors. Our model will be tested by new measurements of b → sℓℓ transitions and also by future electroweak precision tests, direct Z′ searches, and μ-e conversion in nuclei.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
LHCb collaboration, Measurement of Form-Factor-Independent Observables in the Decay B 0 → K *0 μ + μ −, Phys. Rev. Lett. 111 (2013) 191801 [arXiv:1308.1707] [INSPIRE].
LHCb collaboration, Test of lepton universality using B + → K + ℓ + ℓ − decays, Phys. Rev. Lett. 113 (2014) 151601 [arXiv:1406.6482] [INSPIRE].
LHCb collaboration, Angular analysis and differential branching fraction of the decay B 0 s → ϕμ + μ −, JHEP 09 (2015) 179 [arXiv:1506.08777] [INSPIRE].
S. Descotes-Genon, J. Matias and J. Virto, Understanding the B → K * μ + μ − Anomaly, Phys. Rev. D 88 (2013) 074002 [arXiv:1307.5683] [INSPIRE].
W. Altmannshofer and D.M. Straub, New physics in B → K * μμ?, Eur. Phys. J. C 73 (2013) 2646 [arXiv:1308.1501] [INSPIRE].
A. Datta, M. Duraisamy and D. Ghosh, Explaining the B → K * μ + μ − data with scalar interactions, Phys. Rev. D 89 (2014) 071501 [arXiv:1310.1937] [INSPIRE].
F. Beaujean, C. Bobeth and D. van Dyk, Comprehensive Bayesian analysis of rare (semi)leptonic and radiative B decays, Eur. Phys. J. C 74 (2014) 2897 [Erratum ibid. C 74 (2014) 3179] [arXiv:1310.2478] [INSPIRE].
R.R. Horgan, Z. Liu, S. Meinel and M. Wingate, Calculation of B 0 → K *0 μ + μ − and B 0 s → ϕμ + μ − observables using form factors from lattice QCD, Phys. Rev. Lett. 112 (2014) 212003 [arXiv:1310.3887] [INSPIRE].
T. Hurth and F. Mahmoudi, On the LHCb anomaly in B → K * ℓ + ℓ −, JHEP 04 (2014) 097 [arXiv:1312.5267] [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. Hiller and M. Schmaltz, R K and future b → sℓℓ physics beyond the standard model opportunities, Phys. Rev. D 90 (2014) 054014 [arXiv:1408.1627] [INSPIRE].
D. Ghosh, M. Nardecchia and S.A. Renner, Hint of Lepton Flavour Non-Universality in B Meson Decays, JHEP 12 (2014) 131 [arXiv:1408.4097] [INSPIRE].
T. Hurth, F. Mahmoudi and S. Neshatpour, Global fits to b → sℓℓ data and signs for lepton non-universality, JHEP 12 (2014) 053 [arXiv:1410.4545] [INSPIRE].
W. Altmannshofer and D.M. Straub, New physics in b → s transitions after LHC run 1, Eur. Phys. J. C 75 (2015) 382 [arXiv:1411.3161] [INSPIRE].
W. Altmannshofer and D.M. Straub, Implications of b → s measurements, arXiv:1503.06199 [INSPIRE].
W. Altmannshofer, S. Gori, M. Pospelov and I. Yavin, Quark flavor transitions in L μ − L τ models, Phys. Rev. D 89 (2014) 095033 [arXiv:1403.1269] [INSPIRE].
A. Crivellin, G. D’Ambrosio and J. Heeck, Explaining h → μ ± τ ∓ , B → K * μ + μ − and B → Kμ + μ − /B → Ke + e − in a two-Higgs-doublet model with gauged L μ −L τ , Phys. Rev. Lett. 114 (2015) 151801 [arXiv:1501.00993] [INSPIRE].
A. Crivellin, G. D’Ambrosio and J. Heeck, Addressing the LHC flavor anomalies with horizontal gauge symmetries, Phys. Rev. D 91 (2015) 075006 [arXiv:1503.03477] [INSPIRE].
C. Niehoff, P. Stangl and D.M. Straub, Violation of lepton flavour universality in composite Higgs models, Phys. Lett. B 747 (2015) 182 [arXiv:1503.03865] [INSPIRE].
D. Aristizabal Sierra, F. Staub and A. Vicente, Shedding light on the b → s anomalies with a dark sector, Phys. Rev. D 92 (2015) 015001 [arXiv:1503.06077] [INSPIRE].
A. Crivellin, L. Hofer, J. Matias, U. Nierste, S. Pokorski and J. Rosiek, Lepton-flavour violating B decays in generic Z′ models, Phys. Rev. D 92 (2015) 054013 [arXiv:1504.07928] [INSPIRE].
A. Celis, J. Fuentes-Martin, M. Jung and H. Serodio, Family nonuniversal Z′ models with protected flavor-changing interactions, Phys. Rev. D 92 (2015) 015007 [arXiv:1505.03079] [INSPIRE].
A. Greljo, G. Isidori and D. Marzocca, On the breaking of Lepton Flavor Universality in B decays, JHEP 07 (2015) 142 [arXiv:1506.01705] [INSPIRE].
G. Bélanger, C. Delaunay and S. Westhoff, A Dark Matter Relic From Muon Anomalies, Phys. Rev. D 92 (2015) 055021 [arXiv:1507.06660] [INSPIRE].
C. Niehoff, P. Stangl and D.M. Straub, Direct and indirect signals of natural composite Higgs models, arXiv:1508.00569 [INSPIRE].
W. Altmannshofer and I. Yavin, Predictions for lepton flavor universality violation in rare B decays in models with gauged L μ − L τ , Phys. Rev. D 92 (2015) 075022 [arXiv:1508.07009] [INSPIRE].
S. Biswas, D. Chowdhury, S. Han and S.J. Lee, Explaining the lepton non-universality at the LHCb and CMS within a unified framework, JHEP 02 (2015) 142 [arXiv:1409.0882] [INSPIRE].
B. Gripaios, M. Nardecchia and S.A. Renner, Composite leptoquarks and anomalies in B-meson decays, JHEP 05 (2015) 006 [arXiv:1412.1791] [INSPIRE].
S. Sahoo and R. Mohanta, Scalar leptoquarks and the rare B meson decays, Phys. Rev. D 91 (2015) 094019 [arXiv:1501.05193] [INSPIRE].
I. de Medeiros Varzielas and G. Hiller, Clues for flavor from rare lepton and quark decays, JHEP 06 (2015) 072 [arXiv:1503.01084] [INSPIRE].
D. Bečirević, S. Fajfer and N. Košnik, Lepton flavor nonuniversality in B → sℓ + ℓ − processes, Phys. Rev. D 92 (2015) 014016 [arXiv:1503.09024] [INSPIRE].
R. Alonso, B. Grinstein and J.M. Camalich, Lepton universality violation and lepton flavor conservation in B-meson decays, JHEP 10 (2015) 184 [arXiv:1505.05164] [INSPIRE].
L. Calibbi, A. Crivellin and T. Ota, Effective Field Theory Approach to B → sℓℓ (′) , \( B\to {K}^{\left(\ast \right)}\nu \overline{\nu} \) and B → D (*) τν with Third Generation Couplings, Phys. Rev. Lett. 115 (2015) 181801 [arXiv:1506.02661] [INSPIRE].
S. Sahoo and R. Mohanta, Study of the rare semileptonic decays B 0 d → K ∗ l + l − in scalar leptoquark model, arXiv:1507.02070 [INSPIRE].
S.L. Glashow, D. Guadagnoli and K. Lane, Lepton Flavor Violation in B Decays?, Phys. Rev. Lett. 114 (2015) 091801 [arXiv:1411.0565] [INSPIRE].
S.M. Boucenna, J.W.F. Valle and A. Vicente, Are the B decay anomalies related to neutrino oscillations?, Phys. Lett. B 750 (2015) 367 [arXiv:1503.07099] [INSPIRE].
C.-J. Lee and J. Tandean, Minimal lepton flavor violation implications of the b → s anomalies, JHEP 08 (2015) 123 [arXiv:1505.04692] [INSPIRE].
D. Guadagnoli and K. Lane, Charged-Lepton Mixing and Lepton Flavor Violation, Phys. Lett. B 751 (2015) 54 [arXiv:1507.01412] [INSPIRE].
R. Barbieri, G.R. Dvali and L.J. Hall, Predictions from a U(2) flavor symmetry in supersymmetric theories, Phys. Lett. B 377 (1996) 76 [hep-ph/9512388] [INSPIRE].
R. Barbieri, L.J. Hall and A. Romanino, Consequences of a U(2) flavor symmetry, Phys. Lett. B 401 (1997) 47 [hep-ph/9702315] [INSPIRE].
R.G. Roberts, A. Romanino, G.G. Ross and L. Velasco-Sevilla, Precision test of a fermion mass texture, Nucl. Phys. B 615 (2001) 358 [hep-ph/0104088] [INSPIRE].
E. Dudas, G. von Gersdorff, S. Pokorski and R. Ziegler, Linking Natural Supersymmetry to Flavour Physics, JHEP 01 (2014) 117 [arXiv:1308.1090] [INSPIRE].
S. Antusch and V. Maurer, Running quark and lepton parameters at various scales, JHEP 11 (2013) 115 [arXiv:1306.6879] [INSPIRE].
P. Binetruy, S. Lavignac and P. Ramond, Yukawa textures with an anomalous horizontal Abelian symmetry, Nucl. Phys. B 477 (1996) 353 [hep-ph/9601243] [INSPIRE].
P. Binetruy and P. Ramond, Yukawa textures and anomalies, Phys. Lett. B 350 (1995) 49 [hep-ph/9412385] [INSPIRE].
L.E. Ibáñez and G.G. Ross, Fermion masses and mixing angles from gauge symmetries, Phys. Lett. B 332 (1994) 100 [hep-ph/9403338] [INSPIRE].
BaBar collaboration, J.P. Lees et al., Measurement of the B → X s ℓ + ℓ − branching fraction and search for direct CP-violation from a sum of exclusive final states, Phys. Rev. Lett. 112 (2014) 211802 [arXiv:1312.5364] [INSPIRE].
LHCb collaboration, Measurement of the B 0 s → μ + μ − branching fraction and search for B 0 → μ + μ − decays at the LHCb experiment, Phys. Rev. Lett. 111 (2013) 101805 [arXiv:1307.5024] [INSPIRE].
CMS collaboration, Measurement of the B 0 s → μ + μ − branching fraction and search for B 0 → μ + μ − with the CMS Experiment, Phys. Rev. Lett. 111 (2013) 101804 [arXiv:1307.5025] [INSPIRE].
LHCb collaboration, Differential branching fractions and isospin asymmetries of B → K (*) μ + μ − decays, JHEP 06 (2014) 133 [arXiv:1403.8044] [INSPIRE].
T. Iijima, Rare B decays, Conf. Proc. C0908171 (2009) 285 [INSPIRE].
G. Hiller and M. Schmaltz, Diagnosing lepton-nonuniversality in b → sℓℓ, JHEP 02 (2015) 055 [arXiv:1411.4773] [INSPIRE].
Particle Data Group collaboration, K.A. Olive et al., Review of Particle Physics, Chin. Phys. C 38 (2014) 090001 [INSPIRE].
LHCb collaboration, Search for the lepton-flavor violating decays B 0 s → e ± μ ∓ and B 0 → e ± μ ∓, Phys. Rev. Lett. 111 (2013) 141801 [arXiv:1307.4889] [INSPIRE].
ETM collaboration, V. Bertone et al., Kaon Mixing Beyond the SM from N f = 2 tmQCD and model independent constraints from the UTA, JHEP 03 (2013) 089 [Erratum ibid. 1307 (2013) 143] [arXiv:1207.1287] [INSPIRE].
UTfit collaboration, M. Bona et al., Model-independent constraints on ΔF = 2 operators and the scale of new physics, JHEP 03 (2008) 049 [arXiv:0707.0636] [INSPIRE].
ETM collaboration, N. Carrasco et al., B-physics from N f = 2 tmQCD: the Standard Model and beyond, JHEP 03 (2014) 016 [arXiv:1308.1851] [INSPIRE].
N. Carrasco et al., \( {D}^0-{\overline{D}}^0 \) mixing in the standard model and beyond from N f = 2 twisted mass QCD, Phys. Rev. D 90 (2014) 014502 [arXiv:1403.7302] [INSPIRE].
SINDRUM collaboration, U. Bellgardt et al., Search for the Decay μ + → e + e + e −, Nucl. Phys. B 299 (1988) 1 [INSPIRE].
T.S. Kosmas, S. Kovalenko and I. Schmidt, Nuclear μ − − e − conversion in strange quark sea, Phys. Lett. B 511 (2001) 203 [hep-ph/0102101] [INSPIRE].
E. Arganda, M.J. Herrero and A.M. Teixeira, mu-e conversion in nuclei within the CMSSM seesaw: Universality versus non-universality, JHEP 10 (2007) 104 [arXiv:0707.2955] [INSPIRE].
W. Porod, F. Staub and A. Vicente, A Flavor Kit for BSM models, Eur. Phys. J. C 74 (2014) 2992 [arXiv:1405.1434] [INSPIRE].
SINDRUM II collaboration, W.H. Bertl et al., A search for muon to electron conversion in muonic gold, Eur. Phys. J. C 47 (2006) 337 [INSPIRE].
SINDRUM II collaboration, C. Dohmen et al., Test of lepton flavor conservation in μ → e conversion on titanium, Phys. Lett. B 317 (1993) 631 [INSPIRE].
The PRIME Working Group collaboration, Search for the μ → e conversion process at an ultimate sensitivity of the order of 10−18 with prism, LOI to J-PARC 50-GeV PS, LOI-25, http://www-ps.kek.jp/jhf-np/LOIlist/pdf/L25.pdf.
COMET collaboration, Y.G. Cui et al., Conceptual design report for experimental search for lepton flavor violating μ − − e − conversion at sensitivity of 10−16 with a slow-extracted bunched proton beam (COMET), KEK-2009-10 (2009) [INSPIRE].
Mu2e collaboration, R.J. Abrams et al., Mu2e Conceptual Design Report, arXiv:1211.7019 [INSPIRE].
DELPHI, OPAL, LEP Electroweak, ALEPH, L3 collaborations, S. Schael et al., Electroweak Measurements in Electron-Positron Collisions at W-Boson-Pair Energies at LEP, Phys. Rept. 532 (2013) 119 [arXiv:1302.3415] [INSPIRE].
A. Efrati, A. Falkowski and Y. Soreq, Electroweak constraints on flavorful effective theories, JHEP 07 (2015) 018 [arXiv:1503.07872] [INSPIRE].
CMS collaboration, Search for physics beyond the standard model in dilepton mass spectra in proton-proton collisions at \( \sqrt{s}=8 \) TeV, JHEP 04 (2015) 025 [arXiv:1412.6302] [INSPIRE].
Open Access
This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.
Author information
Authors and Affiliations
Corresponding author
Additional information
ArXiv ePrint: 1509.01249
Rights and permissions
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0), which permits use, duplication, adaptation, distribution, and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
About this article
Cite this article
Falkowski, A., Nardecchia, M. & Ziegler, R. Lepton flavor non-universality in B-meson decays from a U(2) flavor model. J. High Energ. Phys. 2015, 173 (2015). https://doi.org/10.1007/JHEP11(2015)173
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP11(2015)173