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arxiv: 2605.01714 · v1 · submitted 2026-05-03 · ✦ hep-ex

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Rare decays of the SM Higgs to light pseudoscalars in the CMS Experiment

Anagha Aravind (for the CMS Collaboration)
Authors on Pith no claims yet

Pith reviewed 2026-05-09 16:44 UTC · model grok-4.3

classification ✦ hep-ex
keywords Higgs bosonlight pseudoscalarsCMSrare decaysRun 213 TeVb quarksleptons
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The pith

The CMS experiment presents an overview of searches for the Standard Model Higgs boson decaying to pairs of light pseudoscalars using 13 TeV Run 2 data.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper gives an overview of searches for the rare decay of the Standard Model Higgs boson to a pair of light pseudoscalars. The searches use proton-proton collision data collected by CMS at a center-of-mass energy of 13 TeV. Various final states are considered, including those with bottom quarks, leptons, and photons. A reader would care because these decays could point to new particles or interactions not predicted by the Standard Model, and the results help narrow down possible extensions to the theory.

Core claim

An overview of selected searches where the SM Higgs boson decays to a pair of light pseudoscalars is presented using Run 2 CMS data at √s=13 TeV. Final states with b quarks, leptons, and photons are discussed.

What carries the argument

The Higgs boson decay to two light pseudoscalars (H → aa) analyzed through their visible decay products in multiple final states.

Load-bearing premise

The analyses assume accurate modeling of Standard Model backgrounds and detector responses so that any potential signal would be distinguishable in the chosen final states.

What would settle it

An excess of events in any final state that exceeds the expected background by a statistically significant amount would require either a signal or a revision of the background model.

Figures

Figures reproduced from arXiv: 2605.01714 by Anagha Aravind (for the CMS Collaboration).

Figure 2
Figure 2. Figure 2: 2 im1 × im2 + im 0.2 0.4 0.6 0.8 1 1.2 3 ×10 Events mH -SR ∩ mA -SR Data Bkg Bkg. unc. (stat + syst) mA = 3 GeV mA = 10 GeV mA = 15 GeV (13 TeV) -1 138 fb CMS Preliminary 0 20 40 60 80 100 2 im1 × im2 + im 0.5 1 1.5 Data / Bkg. 2 4 6 8 10 12 14 [GeV] mA −4 10 −3 10 −2 10 −1 10 1 ) [pb] γ 4 → A A → (H B × H) → (pp σ (13 TeV) -1 138 fb CMS Preliminary Observed Median expected 68% expected 95% expected 95% CL… view at source ↗
Figure 3
Figure 3. Figure 3: Left: Signal topology for h → aa → 4τ /2µ2τ . Middle: Normalized invariant mass distribution of the µ-track system for events passing signal selection. Right: Ob￾served and median expected upper limits at 95% CL for σ(pp → H + X)B(h → aa)B(a → τ τ ) relative to the SM Higgs boson production cross section (σSM) [7]. 2.4 h → aa → bbτ τ A search is performed for h → aa → bbτ τ where 12 < ma < 60 GeV [8]. The … view at source ↗
Figure 4
Figure 4. Figure 4: Left: mττ distribution for µτ channel in one of the signal regions. Middle: Ob￾served and median expected upper limits at 95% CL for h → aa → 2b2τ for the combina￾tion of all 3 channels: eµ, eτh and µτh. Right: Observed upper limits at 95% CL for h → aa obtained from the combination of 2b2τ and µµbb final states for 2HDM+S Type I (inde￾pendent of tan b), Type II (tan b = 2.0%), Type III (tan b = 2.0), and … view at source ↗
Figure 5
Figure 5. Figure 5: Left: CMS results for h → aa → 4γγ in different mass ranges shown in compari￾son with results from the ATLAS experiment [6, 9, 10]. Right: CMS summary plot of recent h → aa results for 2HDM+S Type I interpretation [12]. References [1] CMS Collaboration. The CMS experiment at the CERN LHC. Journal of Instrumen￾tation, 3(08):S08004, Aug 2008. doi: 10.1088/1748-0221/3/08/S08004. URL https://doi.org/10.1088/17… view at source ↗
read the original abstract

An overview of selected searches where the SM Higgs boson decays to a pair of light pseudoscalars is presented using Run 2 CMS data at $\sqrt{s}=13$ TeV. Final states with b quarks, leptons, and photons are discussed.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 2 minor

Summary. The manuscript presents an overview of selected CMS searches for the Standard Model Higgs boson decaying to a pair of light pseudoscalars (h → aa) using Run 2 proton-proton collision data at √s = 13 TeV, with discussion of final states containing b quarks, leptons, and photons.

Significance. If the overview accurately reflects the referenced analyses, it provides a useful consolidation of experimental constraints on light pseudoscalar models, highlighting sensitivities across multiple channels and aiding the community in assessing the status of such rare Higgs decays.

minor comments (2)
  1. The provided abstract is extremely concise and does not mention any specific results, limits, or key findings from the searches; expanding it would improve standalone readability without altering the overview nature of the paper.
  2. Ensure that each discussed analysis (b-quark, lepton, and photon final states) includes explicit citations to the corresponding CMS publications or PAS notes, as the overview relies on those for its content.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for their review of our manuscript. The referee summary accurately captures the content of our overview paper on CMS searches for h → aa decays. The significance assessment is appreciated, and we note the recommendation for minor revision. However, the report contains no specific major comments to address.

Circularity Check

0 steps flagged

No significant circularity identified

full rationale

This is an experimental overview paper summarizing CMS Run 2 searches for h → aa (light pseudoscalar) decays in final states with b quarks, leptons, and photons. No derivation chain, theoretical model, or parameter fitting is claimed or performed in the paper itself; results are inherited from the referenced individual analyses that use collision data and Monte Carlo simulations. The central claim is purely descriptive and does not reduce to any self-definition, fitted input renamed as prediction, or load-bearing self-citation. The paper is self-contained against external benchmarks (published CMS data analyses) with no circular steps.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

The abstract does not specify any free parameters, axioms, or invented entities. The work relies on the established Standard Model and CMS experimental framework without introducing new theoretical constructs.

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discussion (0)

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Reference graph

Works this paper leans on

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