publication . Article . Preprint . 2017

Patterns of New Physics in $b\to s\ell^+\ell^-$ transitions in the light of recent data

Capdevila, Bernat; Crivellin, Andreas; Descotes-Genon, Sébastien; Matias, Joaquim; Virto, Javier;
Open Access English
  • Published: 18 Apr 2017
  • Publisher: HAL CCSD
  • Country: France
Abstract
In the Standard Model (SM), the rare transitions where a bottom quark decays into a strange quark and a pair of light leptons exhibit a potential sensitivity to physics beyond the SM. In addition, the SM embeds Lepton Flavour Universality (LFU), leading to almost identical probabilities for muon and electron modes. The LHCb collaboration discovered a set of deviations from the SM expectations in decays to muons and also in ratios assessing LFU. Other experiments (Belle, ATLAS, CMS) found consistent measurements, albeit with large error bars. We perform a global fit to all available $b\to s\ell^+\ell^-$ data ($\ell=e,\mu$) in a model-independent way allowing for different patterns of New Physics. For the first time, the NP hypothesis is preferred over the SM by $5\,\sigma$ in a general case when NP can enter SM-like operators and their chirally-flipped partners. LFU violation is favoured with respect to LFU at the 3-4$\,\sigma$ level. We discuss the impact of LFU-violating New Physics on the observable $P_5^\prime$ from $B \to K^*\mu^+\mu^-$ and we compare our estimate for long-distance charm contributions with an empirical model recently proposed by a group of LHCb experimentalists. Finally, we discuss NP models able to describe this consistent pattern of deviations.
Comment: 13 pages, 6 figures. Accepted for publication in JHEP
Subjects
arXiv: High Energy Physics::Experiment
free text keywords: lepton: flavor: violation, new physics, numerical calculations, CMS, ATLAS, BELLE, LHC-B, Wilson, effective Hamiltonian, B: branching ratio, B: semileptonic decay, universality: violation, Effective Field Theories, Heavy Quark Physics, lepton: flavor: universality, [ PHYS.HPHE ] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics - Phenomenology, High Energy Physics - Experiment, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]
Funded by
EC| RBI-T-WINNING
Project
RBI-T-WINNING
Ruđer Bošković Institute: Twinning for a step forward of the Theoretical Physics Division
  • Funder: European Commission (EC)
  • Project Code: 692194
  • Funding stream: H2020 | CSA
,
EC| ELUSIVES
Project
ELUSIVES
The Elusives Enterprise: Asymmetries of the Invisible Universe
  • Funder: European Commission (EC)
  • Project Code: 674896
  • Funding stream: H2020 | MSCA-ITN-ETN
,
EC| InvisiblesPlus
Project
InvisiblesPlus
InvisiblesPlus
  • Funder: European Commission (EC)
  • Project Code: 690575
  • Funding stream: H2020 | MSCA-RISE
,
SNSF| Flavour Physics beyond the Standard Model
Project
  • Funder: Swiss National Science Foundation (SNSF)
  • Project Code: PZ00P2_154834
  • Funding stream: Careers | Ambizione
76 references, page 1 of 6

[1] S. Descotes-Genon, T. Hurth, J. Matias and J. Virto, \Optimizing the basis of B ! K `` observables in the full kinematic range," JHEP 1305 (2013) 137 [arXiv:1303.5794 [hep-ph]]. [OpenAIRE]

[2] LHCb Collaboration, \Measurement of Form-FactorIndependent Observables in the Decay B0 ! K 0 + ," PRL 111 (2013) 191801 [arXiv:1308.1707 [hep-ex]].

[3] S. Descotes-Genon, J. Matias and J. Virto, \Understanding the B ! K + Anomaly," Phys. Rev. D 88 (2013) 074002 [arXiv:1307.5683 [hep-ph]].

[4] S. Descotes-Genon, J. Matias, M. Ramon and J. Virto, \Implications from clean observables for the binned analysis of B ! K + at large recoil," JHEP 1301 (2013) 048, [arXiv:1207.2753 [hep-ph]].

[5] R. Aaij et al. [LHCb Collaboration], \Angular analysis of the B0 ! K 0 + decay using 3 fb 1 of integrated luminosity," JHEP 1602 (2016) 104 [arXiv:1512.04442 [hep-ex]].

[6] LHCb Collaboration, \Di erential branching fraction and angular analysis of the decay Bs0 ! + ," JHEP 1307 (2013) 084 [arXiv:1305.2168 [hep-ex]].

[7] LHCb Collaboration, \Angular analysis and di erential branching fraction of the decay Bs0 ! + ," arXiv:1506.08777 [hep-ex].

[8] A. Abdesselam et al. [Belle Collaboration], \Angular analysis of B0 ! K (892)0`+` ," arXiv:1604.04042 [hep-ex].

[9] S. Wehle et al. [Belle Collaboration], \Lepton-FlavorDependent Angular Analysis of B ! K `+` ," Phys. Rev. Lett. 118 (2017) no.11, 111801 [arXiv:1612.05014 [hep-ex]].

[10] LHCb Collaboration, \Test of lepton universality using B+ ! K+`+` decays," Phys. Rev. Lett. 113 (2014) 151601 [arXiv:1406.6482 [hep-ex]].

[11] B. Capdevila, S. Descotes-Genon, J. Matias and J. Virto, \Assessing lepton- avour non-universality from B ! K `` angular analyses," JHEP 1610 (2016) 075 [arXiv:1605.03156 [hep-ph]].

[12] S. Descotes-Genon, L. Hofer, J. Matias and J. Virto, \Global analysis of b ! s`` anomalies," JHEP 1606 (2016) 092 [arXiv:1510.04239 [hep-ph]].

[13] R. Aaij et al. [LHCb Collaboration], \Di erential branching fractions and isospin asymmetries of B ! K( ) + decays," JHEP 1406 (2014) 133 [arXiv:1403.8044 [hepex]].

[14] R. Aaij et al. [LHCb Collaboration], \Measurements of the S-wave fraction in B0 ! K+ + decays and the B0 ! K (892)0 + di erential branching fraction," JHEP 1611, 047 (2016) [arXiv:1606.04731 [hep-ex]].

[15] W. Altmannshofer and D. M. Straub, \New physics in b ! s transitions after LHC run 1," Eur. Phys. J. C 75 (2015) 8, 382 [arXiv:1411.3161 [hep-ph]].

76 references, page 1 of 6
Abstract
In the Standard Model (SM), the rare transitions where a bottom quark decays into a strange quark and a pair of light leptons exhibit a potential sensitivity to physics beyond the SM. In addition, the SM embeds Lepton Flavour Universality (LFU), leading to almost identical probabilities for muon and electron modes. The LHCb collaboration discovered a set of deviations from the SM expectations in decays to muons and also in ratios assessing LFU. Other experiments (Belle, ATLAS, CMS) found consistent measurements, albeit with large error bars. We perform a global fit to all available $b\to s\ell^+\ell^-$ data ($\ell=e,\mu$) in a model-independent way allowing for different patterns of New Physics. For the first time, the NP hypothesis is preferred over the SM by $5\,\sigma$ in a general case when NP can enter SM-like operators and their chirally-flipped partners. LFU violation is favoured with respect to LFU at the 3-4$\,\sigma$ level. We discuss the impact of LFU-violating New Physics on the observable $P_5^\prime$ from $B \to K^*\mu^+\mu^-$ and we compare our estimate for long-distance charm contributions with an empirical model recently proposed by a group of LHCb experimentalists. Finally, we discuss NP models able to describe this consistent pattern of deviations.
Comment: 13 pages, 6 figures. Accepted for publication in JHEP
Subjects
arXiv: High Energy Physics::Experiment
free text keywords: lepton: flavor: violation, new physics, numerical calculations, CMS, ATLAS, BELLE, LHC-B, Wilson, effective Hamiltonian, B: branching ratio, B: semileptonic decay, universality: violation, Effective Field Theories, Heavy Quark Physics, lepton: flavor: universality, [ PHYS.HPHE ] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics - Phenomenology, High Energy Physics - Experiment, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]
Funded by
EC| RBI-T-WINNING
Project
RBI-T-WINNING
Ruđer Bošković Institute: Twinning for a step forward of the Theoretical Physics Division
  • Funder: European Commission (EC)
  • Project Code: 692194
  • Funding stream: H2020 | CSA
,
EC| ELUSIVES
Project
ELUSIVES
The Elusives Enterprise: Asymmetries of the Invisible Universe
  • Funder: European Commission (EC)
  • Project Code: 674896
  • Funding stream: H2020 | MSCA-ITN-ETN
,
EC| InvisiblesPlus
Project
InvisiblesPlus
InvisiblesPlus
  • Funder: European Commission (EC)
  • Project Code: 690575
  • Funding stream: H2020 | MSCA-RISE
,
SNSF| Flavour Physics beyond the Standard Model
Project
  • Funder: Swiss National Science Foundation (SNSF)
  • Project Code: PZ00P2_154834
  • Funding stream: Careers | Ambizione
76 references, page 1 of 6

[1] S. Descotes-Genon, T. Hurth, J. Matias and J. Virto, \Optimizing the basis of B ! K `` observables in the full kinematic range," JHEP 1305 (2013) 137 [arXiv:1303.5794 [hep-ph]]. [OpenAIRE]

[2] LHCb Collaboration, \Measurement of Form-FactorIndependent Observables in the Decay B0 ! K 0 + ," PRL 111 (2013) 191801 [arXiv:1308.1707 [hep-ex]].

[3] S. Descotes-Genon, J. Matias and J. Virto, \Understanding the B ! K + Anomaly," Phys. Rev. D 88 (2013) 074002 [arXiv:1307.5683 [hep-ph]].

[4] S. Descotes-Genon, J. Matias, M. Ramon and J. Virto, \Implications from clean observables for the binned analysis of B ! K + at large recoil," JHEP 1301 (2013) 048, [arXiv:1207.2753 [hep-ph]].

[5] R. Aaij et al. [LHCb Collaboration], \Angular analysis of the B0 ! K 0 + decay using 3 fb 1 of integrated luminosity," JHEP 1602 (2016) 104 [arXiv:1512.04442 [hep-ex]].

[6] LHCb Collaboration, \Di erential branching fraction and angular analysis of the decay Bs0 ! + ," JHEP 1307 (2013) 084 [arXiv:1305.2168 [hep-ex]].

[7] LHCb Collaboration, \Angular analysis and di erential branching fraction of the decay Bs0 ! + ," arXiv:1506.08777 [hep-ex].

[8] A. Abdesselam et al. [Belle Collaboration], \Angular analysis of B0 ! K (892)0`+` ," arXiv:1604.04042 [hep-ex].

[9] S. Wehle et al. [Belle Collaboration], \Lepton-FlavorDependent Angular Analysis of B ! K `+` ," Phys. Rev. Lett. 118 (2017) no.11, 111801 [arXiv:1612.05014 [hep-ex]].

[10] LHCb Collaboration, \Test of lepton universality using B+ ! K+`+` decays," Phys. Rev. Lett. 113 (2014) 151601 [arXiv:1406.6482 [hep-ex]].

[11] B. Capdevila, S. Descotes-Genon, J. Matias and J. Virto, \Assessing lepton- avour non-universality from B ! K `` angular analyses," JHEP 1610 (2016) 075 [arXiv:1605.03156 [hep-ph]].

[12] S. Descotes-Genon, L. Hofer, J. Matias and J. Virto, \Global analysis of b ! s`` anomalies," JHEP 1606 (2016) 092 [arXiv:1510.04239 [hep-ph]].

[13] R. Aaij et al. [LHCb Collaboration], \Di erential branching fractions and isospin asymmetries of B ! K( ) + decays," JHEP 1406 (2014) 133 [arXiv:1403.8044 [hepex]].

[14] R. Aaij et al. [LHCb Collaboration], \Measurements of the S-wave fraction in B0 ! K+ + decays and the B0 ! K (892)0 + di erential branching fraction," JHEP 1611, 047 (2016) [arXiv:1606.04731 [hep-ex]].

[15] W. Altmannshofer and D. M. Straub, \New physics in b ! s transitions after LHC run 1," Eur. Phys. J. C 75 (2015) 8, 382 [arXiv:1411.3161 [hep-ph]].

76 references, page 1 of 6
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