CR007 $pp \to G_{KK}^{(1)} \to ZZ, WW, \gamma\gamma, \ell \ell, t \bar{t}$
Spin-2 KK-graviton resonance (Bulk Randall-Sundrum) Status REVIEWED VERIFIED High Code: NO Priority Medium
PDG / equivalent values
| Observable | Value | Year | Experiment / source | Provenance |
|---|---|---|---|---|
| Lower limit on first RS KK-graviton mass in pp $ \to $ G $ \to \gamma\gamma$ | m(G_KK^(1)) > 4.8 TeV 95% CL (lower_limit) | 2025 | CMS | source ↑ |
| Lower limit on first RS KK-graviton mass in pp $ \to $ G $ \to $ e+e-, $\mu^+\mu^-$ | m(G_KK^(1)) > 4.78 TeV 95% CL (lower_limit) | 2025 | CMS | source ↑ |
| Lower limit on bulk-RS spin-2 graviton mass in pp $ \to $ G $ \to $ WW, ZZ $ \to $ qqqq | m(G_bulk) > 1.4 TeV 95% CL (lower_limit) | 2025 | CMS | source ↑ |
| Lower limit on bulk-RS KK-graviton mass in ATLAS combined bosonic and leptonic final states | m(G_KK) > 2.3 TeV 95% CL (lower_limit) | 2018 | ATLAS | source ↑ |
Why this constrains the RS scan
Bulk RS graviton searches constrain a direct collider resonance mass, not the
\(\Delta F=2\) Wilson coefficients that dominate the existing quark-flavor
pipeline. They are nevertheless useful because custodial bulk-RS spectra often
contain correlated KK gauge bosons, KK gravitons, vectorlike fermions, and
radion-like states at nearby TeV scales. The spin-2 channel is therefore an
RS-distinguishing cross-check of any parameter point that places the first
graviton in the LHC range.
The current low-energy quark scan gives
\(M_{\rm KK}^{\min}(p50,\ g_\ast=3)=47.26~{\rm TeV}\) in
docs/quark\_scan\_methodology\_note.tex. Compared with that
anarchic-flavor bound, the LHC graviton limits above are far weaker as mass
setters. Their value is instead diagnostic: they can veto or reinterpret
non-anarchic, flavor-protected, or custodial RS scenarios whose flavor
constraints have been deliberately weakened, and they provide an external check
on whether the scan has wandered into spectra that would already have produced
a high-mass diboson, diphoton, dilepton, or \(t\bar t\) excess.What's changed since the original paper
The original bulk-RS graviton collider expectation in
AgasheDavoudiaslPerezSoni2007\_WarpedGravitons emphasized suppressed
light-fermion and photon channels but enhanced sensitivity in longitudinal
\(W/Z\) modes. LHC searches after 2010 tested that pattern in stages. Early
Run-1 searches established the first ATLAS/CMS mass and cross-section limits in
\(ZZ\), \(WW\), and combined \(\gamma\gamma/\ell\ell\) channels, replacing the
Tevatron reach. The ATLAS \(36.1~{\rm fb}^{-1}\) combination
(arXiv:1808.02380) mattered because it combined bosonic and leptonic
Run-2 final states into a single bulk-RS spin-2 interpretation.
The full Run-2 ATLAS diboson searches (arXiv:1906.08589 and
arXiv:2004.14636) moved the diboson program into all-hadronic and
semileptonic boosted topologies with \(139~{\rm fb}^{-1}\). CMS then provided
the strongest generic RS spin-2 dilepton benchmark
(arXiv:2103.02708), the current bulk-graviton all-jets diboson
benchmark used here (arXiv:2210.00043), and the current PDG-leading
diphoton benchmark (arXiv:2405.09320). The progression is mainly
in luminosity, boosted-boson tagging, and channel coverage; it is not a move to
a model-independent RS likelihood.Validity and model dependence
The exclusion limits are conditional. They assume a production mechanism,
resonance width, \(k/\overline{M}_{\rm Pl}\), acceptance, and decay-branching
pattern. A headline \(G\to\gamma\gamma\) or \(G\to\ell\ell\) limit is not
automatically applicable to bulk RS models where light-fermion and photon
couplings are suppressed. Conversely, a \(G_{\rm bulk}\to WW/ZZ\) limit does
not directly constrain the KK gluon mass or a custodial fermion mass without a
specified spectrum and branching matrix.
For the anarchic-flavor catalog, the honest use is therefore as a direct-search
side condition: compare the predicted \(G^{(1)}_{\rm KK}\) mass, width, and
branching fractions against the relevant ATLAS/CMS limit curve. A single
mass-threshold cut is only defensible for the exact experimental benchmark
quoted in the sidecar.
Code coverage in this repo
NO. Greps over
quarkConstraints/, qcd/,
flavorConstraints/, neutrinos/, yukawa/,
warpConfig/, solvers/, scanParams/, and
tests/ found no direct ATLAS/CMS, diboson, diphoton, dilepton,
graviton-resonance, or collider-reinterpretation implementation. The only
``CMS'' hit in the collider grep is an unrelated RunDec calibration comment in
tests/test\_alpha\_s.py:89. Adjacent code does carry the scan's
flavor KK scale: quarkConstraints/modern/scan.py:1229--1255
enumerates \(M_{\rm KK}\) for flavor scan points, and
quarkConstraints/modern/evaluation.py:643--666 evaluates the
\(\Delta F=2\) flavor matching at that scale. No separate collider-direct
filter is applied.Implementation difficulty
HIGH. A faithful implementation needs more than a scalar mass cut:
it needs the model point's spin-2 graviton mass, width, production cross
section, branching ratios into \(WW\), \(ZZ\), \(\gamma\gamma\), \(\ell\ell\),
and \(t\bar t\), plus acceptance or a recast of the experimental analysis.
That is naturally an external reinterpretation workflow using tools such as
MadGraph/Pythia/Delphes with CheckMATE, MadAnalysis5, Rivet, or a HEPData-based
likelihood approximation. The repo currently has neither collider event
simulation nor an RS-resonance likelihood interface.
Reason: Needs a new collider-reinterpretation layer: RS spin-2 spectrum prediction, widths, branching fractions, production cross sections, and ATLAS/CMS acceptance or likelihood recasts, likely via MadGraph/Pythia/Delphes plus CheckMATE, MadAnalysis5, Rivet, SModelS, or HEPData-derived limit curves.
Key references
Process-local source keys before bibliography consolidation are
PDG2025\_ExtraDimensions\_RSG, CMS2024\_Diphoton,
CMS2023\_AllJetsBosonPairs, CMS2021\_Dilepton,
ATLAS2020\_SemileptonicDiboson,
ATLAS2019\_HadronicDiboson, ATLAS2018\_Combination,
AgasheDavoudiaslPerezSoni2007\_WarpedGravitons,
AgasheEtAl2007\_WarpedGaugeBosons, and
RandallSundrum1999\_Hierarchy.