Light gauge boson interpretation for (g − 2)μ and the KL→ π0 + (invisible) anomaly at the J-PARC KOTO experiment

Jho, Yongsoo; Lee, Sung Mook; Park, Seong Chan; Park, Yeji; Tseng, Po-Yan

doi:10.1007/jhep04(2020)086

Cited by 35 publications

(29 citation statements)

References 68 publications

(129 reference statements)

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“…Thus, the new physics explanation for the KOTO anomaly is required to generate three anomalous events and satisfy the GN bound. Several such solutions have been proposed in the literature [80,[130][131][132][133][134][135][136][137][138][139][140][141][142][143].…”

Section: Koto Anomalymentioning

confidence: 99%

Explaining (g−2)μ,e , the KOTO anomaly, and the MiniBooNE excess in an extended Higgs model with sterile neutrinos

Dutta

Ghosh

2020

Phys. Rev. D

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We consider a simple extension of the Standard Model (SM) by a complex scalar doublet and a singlet along with three sterile neutrinos. The sterile neutrinos mix with the SM neutrinos to produce three light neutrino states consistent with the oscillation data and three heavy sterile states. The lightest sterile neutrino has lifetime longer than the age of the Universe and can provide correct dark matter relic abundance. Utilizing tree-level flavor changing interactions of a light scalar with mass ∼Oð100Þ MeV along with sterile neutrinos, we can explain the anomalous magnetic moments of both muon and electron, KOTO anomalous events and the MiniBooNE excess simultaneously.

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Section: Koto Anomalymentioning

confidence: 99%

Explaining (g−2)μ,e , the KOTO anomaly, and the MiniBooNE excess in an extended Higgs model with sterile neutrinos

Dutta

Ghosh

2020

Phys. Rev. D

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“…Finally, the NP models of refs. [12,[14][15][16][17][18][19][20][21] do not violate the GN bound, but can allow for a large signal in KOTO since NA62 is not sensitive to X inv with a mass close to the pion mass.…”

Section: Jhep07(2020)229mentioning

confidence: 99%

Three exceptions to the Grossman-Nir bound

Ziegler

Zupan

Zwicky

2020

J. High Energ. Phys.

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We show that the Grossman-Nir (GN) bound, Br(K L → π 0 νν) ≤ 4.3 Br(K + → π + νν), can be violated in the presence of light new physics with flavor violating couplings. We construct three sample models in which the GN bound can be violated by orders of magnitude, while satisfying all other experimental bounds. In the three models the enhanced branching ratio Br(K L → π 0 + inv) is due to K

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“…Here we adopt the framework of effective field theory below the electroweak scale, where all the effective operators respect the SM residual gauge symmetry U(1) em × SU(3) color and contain only 1 Several different scenarios involving new particles contributing to K → π plus missing energy to break the GN bound have been studied recently [10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Breaking the Grossman-Nir bound in kaon decays

Dong

Tandean

et al. 2020

J. High Energ. Phys.

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The ratio B(K L → π 0 νν)/B(K + → π + νν) of the branching fractions of kaon decays K L → π 0 νν and K + → π + νν has a maximum of about 4.3 under the assumption that the underlying interactions change isospin by ∆I = 1/2. This is referred to as the Grossman-Nir (GN) bound, which is respected by the standard model (SM) and by many scenarios beyond it. Recent preliminary results of the KOTO and NA62 Collaborations searching for these kaon modes seem to imply a violation of this bound. The KOTO findings also suggest that B(K L → π 0 νν) could be much larger, by nearly two orders of magnitude, than that predicted in the SM. In this work we study the possibility of violating the GN bound in an effective field theory approach with only SM fields. We show that the bound holds, in addition to the original GN scenarios, whether or not the kaon decays conserve lepton number. We demonstrate that the inclusion of ∆I = 3/2 operators can lead to a violation of the GN bound and illustrate with an example of how the KOTO numbers may be reached with a new physics scale of order tens of GeV.Recently the KOTO Collaboration has presented a preliminary report on its latest search for the flavor-changing neutral current (FCNC) decay of neutral kaon K L into a neutral pion π 0 and an unobserved neutrino pair (2ν), having achieved a single event sensitivity of 6.9 × 10 −10 and showing 3 candidate events in the signal region [1]. Should these turn out to be real signal events, they would imply a branching fraction of B(K L → π 0 2ν) 2.1 × 10 −9 , which is greater by almost two orders of magnitude than the standard model (SM) prediction [2-4]: B(K L → π 0 νν) SM = (3.0 ± 0.2) × 10 −11 . If confirmed in the future, this huge enhancement seen by KOTO would constitute early evidence for new physics (NP) beyond the SM in the quark sector. For comparison, KOTO [5] earlier set the limit B(K 0 L → π 0 2ν) KOTO15 < 3.0 × 10 −9 at 90% confidence level (CL).

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Light gauge boson interpretation for (g − 2)μ and the KL→ π0 + (invisible) anomaly at the J-PARC KOTO experiment

Cited by 35 publications

References 68 publications

Explaining (g−2)μ,e , the KOTO anomaly, and the MiniBooNE excess in an extended Higgs model with sterile neutrinos

Explaining (g−2)μ,e , the KOTO anomaly, and the MiniBooNE excess in an extended Higgs model with sterile neutrinos

Three exceptions to the Grossman-Nir bound

Breaking the Grossman-Nir bound in kaon decays

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