New physics in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>b</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>s</mml:mi><mml:msup><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math> after the measurement of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>R</mml:mi></mml:mrow><mml:mrow><mml:msup><mml:mrow><mml:mi>K</mml:mi></mml:mrow><mml:mrow><mml:mo>*</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:msub></mml:mrow></mml:math>
Bibliographic record
Abstract
The recent measurement of ${R}_{{K}^{*}}$ is yet another hint of new physics (NP) and supports the idea that it is present in $b\ensuremath{\rightarrow}s{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ decays. We perform a combined model-independent and model-dependent analysis in order to deduce properties of this NP. Like others, we find that the NP must obey one of two scenarios: (I) ${C}_{9}^{\ensuremath{\mu}\ensuremath{\mu}}(\mathrm{NP})<0$ or (II) ${C}_{9}^{\ensuremath{\mu}\ensuremath{\mu}}(\mathrm{NP})=\ensuremath{-}{C}_{10}^{\ensuremath{\mu}\ensuremath{\mu}}(\mathrm{NP})<0$. A third scenario, (III) ${C}_{9}^{\ensuremath{\mu}\ensuremath{\mu}}(\mathrm{NP})=\ensuremath{-}{C}_{9}^{\ensuremath{'}\ensuremath{\mu}\ensuremath{\mu}}(\mathrm{NP})$, is rejected largely because it predicts ${R}_{K}=1$, in disagreement with experiment. The simplest NP models involve the tree-level exchange of a leptoquark (LQ) or a ${Z}^{\ensuremath{'}}$ boson. We show that scenario II can arise in LQ or ${Z}^{\ensuremath{'}}$ models, but scenario I is only possible with a ${Z}^{\ensuremath{'}}$. Fits to ${Z}^{\ensuremath{'}}$ models must take into account the additional constraints from ${B}_{s}^{0}\text{\ensuremath{-}}{\overline{B}}_{s}^{0}$ mixing and neutrino trident production. Although the LQs must be heavy, O(TeV), we find that the ${Z}^{\ensuremath{'}}$ can be light, e.g., ${M}_{{Z}^{\ensuremath{'}}}=10\text{ }\text{ }\mathrm{GeV}$ or 200 MeV.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.008 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.002 | 0.003 |
| Bibliometrics | 0.004 | 0.004 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.014 | 0.013 |
| Open science | 0.004 | 0.004 |
| Research integrity | 0.004 | 0.007 |
| Insufficient payload (model declined to judge) | 0.728 | 0.630 |
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 source (direct Gemma or distilled Codex), 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".