Abstract
The B → K ∗ μμ decay exhibits deviations with respect to Standard Model expectations and the measurement of the ratio R K hints at a violation of lepton-flavour universality in B → Kℓℓ transitions. Both effects can be understood in model-independent fits as a short-distance contribution to the Wilson coefficient C 9μ , with some room for similar contributions in other Wilson coefficients for b → sμμ transitions. We discuss how a full angular analysis of B → K ∗ ee and its comparison with B → K ∗ μμ could improve our understanding of these anomalies and help confirming their interpretation in terms of short-distance New Physics. We discuss several observables of interest in this context and provide predictions for them within the Standard Model as well as within several New Physics benchmark scenarios. We pay special attention to the sensitivity of these observables to hadronic uncertainties from SM contributions with charm loops.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
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].
S. Descotes-Genon, J. Matias, M. Ramon and J. Virto, Implications from clean observables for the binned analysis of B → K ∗ μ + μ − at large recoil, JHEP 01 (2013) 048 [arXiv:1207.2753] [INSPIRE].
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, Angular analysis of the B 0 → K ∗0 μ + μ − decay using 3 fb −1 of integrated luminosity, JHEP 02 (2016) 104 [arXiv:1512.04442] [INSPIRE].
Belle collaboration, A. Abdesselam et al., Angular analysis of B 0 → K ∗(892)0 ℓ + ℓ −, arXiv:1604.04042 [INSPIRE].
LHCb collaboration, Differential branching fraction and angular analysis of the decay B 0 → K ∗0 μ + μ −, JHEP 08 (2013) 131 [arXiv:1304.6325] [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].
LHCb collaboration, Angular analysis of charged and neutral B → Kμ + μ − decays, JHEP 05 (2014) 082 [arXiv:1403.8045] [INSPIRE].
LHCb collaboration, Test of lepton universality using B + → K + ℓ + ℓ − decays, Phys. Rev. Lett. 113 (2014) 151601 [arXiv:1406.6482] [INSPIRE].
BaBar collaboration, J.P. Lees et al., Measurement of an excess of \( \overline{B}\to {D}^{\left(\ast \right)}\tau -{\overline{\nu}}_{\tau } \) decays and implications for charged Higgs bosons, Phys. Rev. D 88 (2013) 072012 [arXiv:1303.0571] [INSPIRE].
Belle collaboration, M. Huschle et al., Measurement of the branching ratio of \( \overline{B}\to {D}^{\left(\ast \right)}\tau -{\overline{\nu}}_{\tau } \) relative to \( \overline{B}\to {D}^{\left(\ast \right)}l-{\overline{\nu}}_l \) decays with hadronic tagging at Belle, Phys. Rev. D 92 (2015) 072014 [arXiv:1507.03233] [INSPIRE].
LHCb collaboration, Measurement of the ratio of branching fractions \( \mathrm{\mathcal{B}}\left({\overline{B}}^0\to {D}^{\ast +}{\tau}^{-}{\overline{\nu}}_{\tau}\right)/\mathrm{\mathcal{B}}\left({\overline{B}}^0\to {D}^{\ast +}{\mu}^{-}{\overline{\nu}}_{\mu}\right) \), Phys. Rev. Lett. 115 (2015) 111803 [Addendum ibid. 115 (2015) 159901] [arXiv:1506.08614] [INSPIRE].
Belle collaboration, A. Abdesselam et al., Measurement of the branching fraction and CP asymmetry in radiative D 0 → V γ decays, arXiv:1603.03257 [INSPIRE].
D. Becirevic and E. Schneider, On transverse asymmetries in B → K ∗ ℓ + ℓ −, Nucl. Phys. B 854 (2012) 321 [arXiv:1106.3283] [INSPIRE].
J. Matias, F. Mescia, M. Ramon and J. Virto, Complete anatomy of \( {\overline{B}}_d\to {\overline{K}}^{\ast 0}\left(\to K\pi \right){l}^{+}{l}^{-} \) and its angular distribution, JHEP 04 (2012) 104 [arXiv:1202.4266] [INSPIRE].
BaBar collaboration, J.P. Lees et al., Measurement of angular asymmetries in the decays B→K ∗ ℓ + ℓ −, Phys. Rev. D 93 (2016) 052015 [arXiv:1508.07960] [INSPIRE].
M. Beneke, T. Feldmann and D. Seidel, Systematic approach to exclusive B → V l + l − , V γ decays, Nucl. Phys. B 612 (2001) 25 [hep-ph/0106067] [INSPIRE].
W. Altmannshofer and D.M. Straub, New physics in B → K ∗ μμ?, Eur. Phys. J. C 73 (2013) 2646 [arXiv:1308.1501] [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].
T. Hurth and F. Mahmoudi, On the LHCb anomaly in B → K ∗ ℓ + ℓ −, JHEP 04 (2014) 097 [arXiv:1312.5267] [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].
S. Descotes-Genon, L. Hofer, J. Matias and J. Virto, Global analysis of b → sℓℓ anomalies, JHEP 06 (2016) 092 [arXiv:1510.04239] [INSPIRE].
W. Altmannshofer and D.M. Straub, Implications of b → s measurements, arXiv:1503.06199 [INSPIRE].
T. Hurth, F. Mahmoudi and S. Neshatpour, On the anomalies in the latest LHCb data, Nucl. Phys. B 909 (2016) 737 [arXiv:1603.00865] [INSPIRE].
A. Khodjamirian, T. Mannel, A.A. Pivovarov and Y.M. Wang, Charm-loop effect in B→K (∗) ℓ + ℓ − and B→K ∗γ, JHEP 09 (2010) 089 [arXiv:1006.4945] [INSPIRE].
S. Jäger and J. Martin Camalich, On B → V ℓℓ at small dilepton invariant mass, power corrections and new physics, JHEP 05 (2013) 043 [arXiv:1212.2263] [INSPIRE].
S. Jäger and J. Martin Camalich, Reassessing the discovery potential of the B → K ∗ ℓ + ℓ − decays in the large-recoil region: SM challenges and BSM opportunities, Phys. Rev. D 93 (2016) 014028 [arXiv:1412.3183] [INSPIRE].
J. Lyon and R. Zwicky, Resonances gone topsy turvy — The charm of QCD or new physics in b → sℓ + ℓ − ?, arXiv:1406.0566 [INSPIRE].
M. Ciuchini et al., B → K ∗ ℓ + ℓ − decays at large recoil in the Standard Model: a theoretical reappraisal, JHEP 06 (2016) 116 [arXiv:1512.07157] [INSPIRE].
LHCb collaboration, Angular analysis of the B 0 → K ∗0 e + e − decay in the low-q 2 region, JHEP 04 (2015) 064 [arXiv:1501.03038] [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].
G. Hiller and M. Schmaltz, Diagnosing lepton-nonuniversality in b → sℓℓ, JHEP 02 (2015) 055 [arXiv:1411.4773] [INSPIRE].
B. Bhattacharya, A. Datta, D. London and S. Shivashankara, Simultaneous explanation of the R K and R(D (∗)) puzzles, Phys. Lett. B 742 (2015) 370 [arXiv:1412.7164] [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].
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].
F. Mahmoudi, S. Neshatpour and J. Virto, B → K ∗ μ + μ − optimised observables in the MSSM, Eur. Phys. J. C 74 (2014) 2927 [arXiv:1401.2145] [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].
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].
R. Alonso, B. Grinstein and J. Martin Camalich, Lepton universality violation and lepton flavor conservation in B-meson decays, JHEP 10 (2015) 184 [arXiv:1505.05164] [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].
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].
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].
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].
M. Bauer and M. Neubert, Minimal leptoquark explanation for the R D (∗) , R K and (g − 2) g anomalies, Phys. Rev. Lett. 116 (2016) 141802 [arXiv:1511.01900] [INSPIRE].
S. Fajfer and N. Košnik, Vector leptoquark resolution of R K and R D (∗) puzzles, Phys. Lett. B 755 (2016) 270 [arXiv:1511.06024] [INSPIRE].
S.M. Boucenna, A. Celis, J. Fuentes-Martin, A. Vicente and J. Virto, Non-abelian gauge extensions for B-decay anomalies, Phys. Lett. B 760 (2016) 214 [arXiv:1604.03088] [INSPIRE].
S.M. Boucenna, A. Celis, J. Fuentes-Martin, A. Vicente and J. Virto, Phenomenology of an SU(2) × SU(2) × U (1) model with lepton-flavour non-universality, arXiv:1608.01349 [INSPIRE].
D. Buttazzo, A. Greljo, G. Isidori and D. Marzocca, Toward a coherent solution of diphoton and flavor anomalies, JHEP 08 (2016) 035 [arXiv:1604.03940] [INSPIRE].
M. Beylich, G. Buchalla and T. Feldmann, Theory of B → K (∗) ℓ + ℓ − decays at high q 2 : OPE and quark-hadron duality, Eur. Phys. J. C 71 (2011) 1635 [arXiv:1101.5118] [INSPIRE].
B. Grinstein and D. Pirjol, Exclusive rare B → K ∗ ℓ + ℓ − decays at low recoil: controlling the long-distance effects, Phys. Rev. D 70 (2004) 114005 [hep-ph/0404250] [INSPIRE].
A. Khodjamirian, T. Mannel and Y.M. Wang, B → Kℓ+ℓ− decay at large hadronic recoil, JHEP 02 (2013) 010 [arXiv:1211.0234] [INSPIRE].
R. Mandal, R. Sinha and D. Das, Testing new physics effects in B → K ∗ ℓ + ℓ −, Phys. Rev. D 90 (2014) 096006 [arXiv:1409.3088] [INSPIRE].
S. Descotes-Genon, T. Hurth, J. Matias and J. Virto, Optimizing the basis of B → K ∗ ll observables in the full kinematic range, JHEP 05 (2013) 137 [arXiv:1303.5794] [INSPIRE].
S. Descotes-Genon, L. Hofer, J. Matias and J. Virto, On the impact of power corrections in the prediction of B → K ∗ μ + μ − observables, JHEP 12 (2014) 125 [arXiv:1407.8526] [INSPIRE].
W. Altmannshofer, P. Ball, A. Bharucha, A.J. Buras, D.M. Straub and M. Wick, Symmetries and asymmetries of B → K ∗ μ + μ − decays in the standard model and beyond, JHEP 01 (2009) 019 [arXiv:0811.1214] [INSPIRE].
D. Becirevic and A. Tayduganov, Impact of B → K *0 ℓ + ℓ − on the new physics search in B→K ∗ℓ+ℓ− decay, Nucl. Phys. B 868 (2013) 368 [arXiv:1207.4004] [INSPIRE].
J. Matias, On the S-wave pollution of B → K ∗ ℓ + ℓ − observables, Phys. Rev. D 86 (2012) 094024 [arXiv:1209.1525] [INSPIRE].
T. Blake, U. Egede and A. Shires, The effect of S-wave interference on the B 0 → K ∗0 ℓ + ℓ − angular observables, JHEP 03 (2013) 027 [arXiv:1210.5279] [INSPIRE].
F. Krüger and J. Matias, Probing new physics via the transverse amplitudes of B 0 → K ∗0(→ K − π +)ℓ + ℓ − at large recoil, Phys. Rev. D 71 (2005) 094009 [hep-ph/0502060] [INSPIRE].
N. Serra, private communication.
U. Egede, M. Patel and K.A. Petridis, Method for an unbinned measurement of the q 2 dependent decay amplitudes of \( {\overline{B}}^0\to\ {K}^{\ast 0}{\mu}^{+}{\mu}^{-} \) decays, JHEP 06 (2015) 084 [arXiv:1504.00574] [INSPIRE].
M. Beneke and T. Feldmann, Symmetry breaking corrections to heavy to light B meson form-factors at large recoil, Nucl. Phys. B 592 (2001) 3 [hep-ph/0008255] [INSPIRE].
A. Bharucha, D.M. Straub and R. Zwicky, B → V ℓ + ℓ − in the Standard Model from light-cone sum rules, JHEP 08 (2016) 098 [arXiv:1503.05534] [INSPIRE].
B.Capdevila, S. Descotes-Genon, L. Hofer and J. Matias, in preparation.
E. Barberio and Z. Was, PHOTOS: a universal Monte Carlo for QED radiative corrections. Version 2.0, Comput. Phys. Commun. 79 (1994) 291 [INSPIRE].
P. Stoffer, Isospin breaking effects in K ℓ4 decays, Eur. Phys. J. C 74 (2014) 2749 [arXiv:1312.2066] [INSPIRE].
V. Bernard, S. Descotes-Genon and M. Knecht, On some aspects of isospin breaking in the \( {K}^{\pm}\to {\pi}^0{\pi}^0{e}^{\pm}\;\overset{\left(-\right)}{v_e} \), Eur. Phys. J. C 75 (2015) 145 [arXiv:1501.07102] [INSPIRE].
M. Bordone, G. Isidori and A. Pattori, On the Standard Model predictions for R K and R K ∗ , Eur. Phys. J. C 76 (2016) 440 [arXiv:1605.07633] [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: 1605.03156
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
Capdevila, B., Descotes-Genon, S., Matias, J. et al. Assessing lepton-flavour non-universality from B →K ∗ ℓℓ angular analyses. J. High Energ. Phys. 2016, 75 (2016). https://doi.org/10.1007/JHEP10(2016)075
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP10(2016)075