Light resonances and the low-q2 bin of $$ {R}_{K^{*}} $$
Bibliographic record
Abstract
A bstract LHCb has reported hints of lepton-flavor universality violation in the rare decays B → K (*) ℓ + ℓ − , both in high- and low- q 2 bins. Although the high- q 2 hint may be explained by new short-ranged interactions, the low- q 2 one cannot. We thus explore the possibility that the latter is explained by a new light resonance. We find that LHCb’s central value of $$ {R}_{K^{*}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>R</mml:mi> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>*</mml:mo> </mml:msup> </mml:msub> </mml:math> in the low- q 2 bin is achievable in a restricted parameter space of new-physics scenarios in which the new, light resonance decays preferentially to electrons and has a mass within approximately 10 MeV of the di-muon threshold. Interestingly, such an explanation can have a kinematic origin and does not require a source of lepton-flavor universality violation. A model-independent prediction is a narrow peak in the differential B → K * e + e − rate close to the di-muon threshold. If such a peak is observed, other observables, such as the differential B → Ke + e − rate and R K , may be employed to distinguish between models. However, if a low-mass resonance is not observed and the low- q 2 anomaly increases in significance, then the case for an experimental origin of the lepton-flavor universality violating anomalies would be strengthened. To further explore this, we also point out that, in analogy to J/ψ decays, e + e − and μ + μ − decays of ϕ mesons can be used as a cross check of lepton-flavor universality by LHCb with 5 fb −1 of integrated luminosity.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".