Possible explanation of the electron positron anomaly at 17 MeV in 8 Be transitions through a light pseudoscalar

Ellwanger, Ulrich; Moretti, Stefano

doi:10.1007/jhep11(2016)039

Cited by 87 publications

(86 citation statements)

References 52 publications

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“…For example, an important contribution to flavour-changing processes may arise from pseudoscalar-Higgs interactions or interactions between the pseudoscalar and SU (2) L gauge bosons [63]. Furthermore, in specific UV completions there may be additional non-logarithmic contributions, which become important if Λ is small, in particular if they have the opposite sign [64]. Finally, mixing between the pseudoscalar and QCD resonances may enhance the rate of rare B-meson decays for specific pseudoscalar masses.…”

Section: Model-independent Boundsmentioning

confidence: 99%

Model-independent bounds on light pseudoscalars from rare B-meson decays

et al. 2019

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New light pseudoscalars, such as axion-like particles, appear in many well-motivated extensions of the Standard Model and provide an exciting target for present and future experiments. We study the experimental sensitivity for such particles by revising the CHARM exclusion contour, updating bounds from LHCb and presenting prospects for NA62 and SHiP. We first consider a simplified model of a light pseudoscalar A and then propose a model-independent approach applicable to any spin-0 boson light enough to be produced in B-meson decays. As illustration, we provide upper bounds on BR(B → K A)×BR(A → µ + µ − ) as a function of the boson lifetime and mass for models that satisfy minimal flavour violation. Our results demonstrate the important complementarity between different experiments resulting from their different geometries.

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Section: Model-independent Boundsmentioning

confidence: 99%

Model-independent bounds on light pseudoscalars from rare B-meson decays

et al. 2019

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“…It has been shown that in order to be compatible with existing experimental constraints, the new vector boson should be protophobic [31], i.e., the coupling to proton is highly suppressed compared with the coupling to neutron. This proposal has stimulated many related works [33][34][35][36][37][38][39][40][41].…”

Section: Introductionmentioning

confidence: 96%

Naturalness and a light Z′

2017

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Models with a light, additional gauge boson are attractive extensions of the standard model. Often these models are only considered as effective low energy theory without any assumption about an UV completion. This leaves not only the hierarchy problem of the SM unsolved, but introduces a copy of it because of the new fundamental scalars responsible for breaking the new gauge group. A possible solution is to embed these models into a supersymmetric framework. However, this gives rise to an additional source of fine-tuning compared to the MSSM and poses the question how natural such a setup is. One might expect that the additional fine-tuning is huge, namely, O(M 2 SUSY /m 2 Z ). In this paper we point out that this is not necessarily the case. We show that it is possible to find a focus point behaviour also in the new sector in co-existence to the MSSM focus point. We call this 'Double Focus Point Supersymmetry'. Moreover, we stress the need for a proper inclusion of radiative corrections in the fine-tuning calculation: a tree-level estimate would lead to predictions for the tuning which can be wrong by many orders of magnitude. As showcase, we use the U (1)B−L extended MSSM and discuss possible consequence of the observed 8 Be anomaly. However, similar features are expected for other models with an extended gauge group which involve potentially large Yukawa-like interactions of the new scalars.

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“…Also, these facilitate the simultaneous opening up of the decays χ 0 2,3 → χ 0 1 h 2 (h SM ) thus reinforcing the combined branching fractions of χ 0 2,3 to Higgs bosons over the same to Z-boson. Some specific consequences of such possibilities had been studied in the past which include rather light scalars decaying to (i) ττ and leading to soft multi-lepton final state [40], (ii) bb [41] and (iii) two photons [42,43]. For m a 1 1 GeV, even mesons can be produced out of a boosted pair of light quarks that a 1 /h 1 might decay to.…”

Section: Introductionmentioning

confidence: 99%

Revisiting singlino dark matter of the natural Z3-symmetric NMSSM in the light of LHC

Abdallah

Chatterjee

Datta

2019

J. High Energ. Phys.

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Inspired by the fact that relatively small values of the effective higgsino mass parameter of the Z 3 -symmetric Next-to-Minimal Supersymmetric Standard Model (NMSSM) could render the scenario 'natural', we explore the plausibility of having relatively light neutralinos and charginos (the electroweakinos or the ewinos) in such a scenario with a rather light singlino-like Lightest Supersymmetric Particle (LSP), which is a Dark Matter (DM) candidate, and singlet-dominated scalar excitations. By first confirming the indications in the existing literature that finding simultaneous compliance with results from the Large Hadron Collider (LHC) and those from various DM experiments with such light states is, in general, a difficult ask, we proceed to demonstrate, with the help of a few representative benchmark points, how exactly and to what extent could such a highly motivated 'natural' setup with a singlino-like DM candidate still remains plausible.

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Possible explanation of the electron positron anomaly at 17 MeV in 8 Be transitions through a light pseudoscalar

Cited by 87 publications

References 52 publications

Model-independent bounds on light pseudoscalars from rare B-meson decays

Model-independent bounds on light pseudoscalars from rare B-meson decays

Naturalness and a light Z′

Revisiting singlino dark matter of the natural Z3-symmetric NMSSM in the light of LHC

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