arxiv: 2604.07093 · v1 · submitted 2026-04-08 · ✦ hep-ph

LHC di-dijet excesses as signals of fourth-generation tetraquarks

Hsiang-nan Li This is my paper

Pith reviewed 2026-05-10 18:22 UTC · model grok-4.3

classification ✦ hep-ph

keywords fourth-generation quarkstetraquarksdi-dijet excessesLHCYukawa potentialcolor-octet scalarsHiggs boson exchangesbeyond Standard Model

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The pith

LHC di-dijet excesses arise from resonant production of fourth-generation b' tetraquarks at masses near 2 TeV.

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

The paper argues that unexplained excesses in di-dijet events at the LHC come from production of four fourth-generation quarks b' each with mass around 2 TeV. These quarks form tetraquarks and bound states in a potential generated by Higgs boson exchanges, yielding resonances that match observed peaks at four-jet masses of 8 TeV and 3.6 TeV. The dijet masses near 2 TeV and 0.95 TeV correspond to first excited color-octet scalar states and ground-state color-octet vectors, respectively. A sympathetic reader would care because the setup unifies several reported anomalies into one framework involving heavy quarks and color-octet particles while drawing a direct parallel to lower-energy tetraquark searches. It also shows that the required bound-state spectrum is generated naturally for the stated quark mass.

Core claim

We postulate that the excesses of di-dijet events observed at the LHC are attributed to the production of four fourth-generation quarks b' with a mass m_b'≈2 TeV at few-TeV scales. The di-dijet signals around the four-jet invariant mass m_4j≈8 TeV arise from a resonant b'b'b'b' tetraquark production, where the dijet resonances of masses about 2 TeV correspond to b'b' first excited states (color-octet scalars with the principal quantum number n=2) in a Yukawa potential created by Higgs boson exchanges. Those around m_4j≈3.6 TeV originate from a non-resonant b'b'b'b' production, where the dijet resonances of masses 0.95 TeV correspond to b'b' ground states (color-octet vectors with n=1). It is

What carries the argument

The Yukawa potential generated by Higgs boson exchanges that supports bound states of b' and b'bar quarks, producing color-octet scalars at n=2 and color-octet vectors at n=1 for m_b'≈2 TeV.

If this is right

Resonant b'b'b'b' tetraquark production explains the di-dijet signals at m_4j≈8 TeV with 2 TeV dijet resonances as n=2 color-octet scalars.
Non-resonant b'b'b'b' production accounts for the signals at m_4j≈3.6 TeV with 0.95 TeV dijet resonances as n=1 color-octet vectors.
The b'b' system with m_b'≈2 TeV in the Higgs-exchange Yukawa potential generates the observed bound-state spectrum.
Events at m_4j=6.6 TeV and 5.8 TeV with dijet masses near 2 TeV are accommodated in the same framework.
The fourth-generation setup maps onto existing effective theories of color-octet scalars and vectors.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

Confirmation would constitute evidence for a fourth generation of quarks whose existence has been constrained but not excluded by other searches.
The framework predicts additional resonances at higher excitations that could be targeted in high-luminosity LHC runs or in associated production channels.
The analogy to GeV-scale fully-charmed tetraquarks suggests a general pattern of heavy-quark bound states that may appear across widely different energy scales.
Direct searches for fourth-generation quarks in other final states could provide independent tests of the 2 TeV mass scale assumed here.

Load-bearing premise

The observed di-dijet excesses must be produced by fourth-generation b' quarks forming the specific tetraquark and bound-state spectrum described, rather than by other Standard Model backgrounds, detector effects, or unrelated beyond-Standard-Model processes.

What would settle it

A full reanalysis of LHC four-jet data that fails to reproduce the predicted resonant and non-resonant production rates or the exact mass peaks at m_4j≈8 TeV and 3.6 TeV for b' quarks of mass 2 TeV would falsify the claim.

Figures

Figures reproduced from arXiv: 2604.07093 by Hsiang-nan Li.

**Figure 2.** Figure 2: FIG. 2: Effective diagrams with (a) colorons (wavy lines) and color-octet scalars (dashed lines), and (b) two different colorons. [PITH_FULL_IMAGE:figures/full_fig_p006_2.png] view at source ↗

read the original abstract

We postulate that the excesses of di-dijet events observed at the LHC are attributed to the production of four fourth-generation quarks $b'$ with a mass $m_{b'}\approx 2$ TeV at few-TeV scales. The di-dijet signals around the four-jet invariant mass $m_{4j}\approx 8$ TeV arise from a resonant $b'b'\bar b'\bar b'$ tetraquark production, where the dijet resonances of masses about 2 TeV correspond to $b'\bar b'$ first excited states (color-octet scalars with the principal quantum number $n=2$) in a Yukawa potential created by Higgs boson exchanges. Those around $m_{4j}\approx 3.6$ TeV originate from a non-resonant $b'b'\bar b'\bar b'$ production, where the dijet resonances of masses 0.95 TeV correspond to $b'\bar b'$ ground states (color-octet vectors with $n=1$). It is shown that a $b'\bar b'$ system with $m_{b'}\approx 2$ TeV in the Yukawa potential does generate the aforementioned bound state spectrum. We then illustrate that the observed excesses can be accommodated in our setup by translating the fourth-generation model to the effective theories containing color-octet scalars and vectors available in the literature. The di-dijet events at $m_{4j}= 6.6$ TeV and 5.8 TeV with dijet masses about 2 TeV can also be interpreted in the same framework. Simply speaking, our scenario can be viewed as a TeV-scale version of the search for a fully charmed tetraquark via the four-muon channels $X(6900)\to (c\bar c)(c\bar c)\to 4\mu$ at a GeV scale.

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.

Desk Editor's Note private letter to a colleague

This paper fits some LHC di-dijet excesses to fourth-generation b' quarks forming tetraquarks via a Higgs Yukawa potential, but the bound-state masses are assigned to match the data rather than derived independently.

read the letter

This paper claims that LHC di-dijet excesses come from fourth-generation b' quarks of mass about 2 TeV forming tetraquarks and bound states through a Higgs Yukawa potential. What stands out is the attempt to link these excesses to a specific spectrum of color-octet states with principal quantum numbers n=1 and n=2. The work draws on existing ideas about tetraquarks and effective theories for color-octet scalars and vectors, then translates the fourth-generation setup into that language. It also draws a parallel to the search for the fully charmed tetraquark X(6900). The paper does well in outlining how resonant production at m_4j around 8 TeV and non-resonant at lower values could account for the reported peaks at 6.6 and 5.8 TeV as well. The main weakness is that the bound-state masses are assigned to match the dijet resonances at 2 TeV and 0.95 TeV. The abstract states that the Yukawa potential generates the required spectrum, yet the details of solving for the eigenvalues, including the color factor in the octet channel and the large Yukawa coupling y_b' of order 11, are not laid out. This makes the explanation look like a post-hoc fit rather than an independent prediction from the model. No new cross-section calculations or background estimates appear to be provided. This paper is aimed at theorists who explore exotic interpretations of LHC anomalies. Readers seeking rigorous derivations or falsifiable predictions beyond the current data will find limited value. It deserves a serious referee because the scenario is specific and can be tested against the bound-state calculation and production rates. A review would likely focus on whether the potential really produces those states without fine-tuning.

Referee Report

3 major / 3 minor

Summary. The manuscript postulates that observed LHC di-dijet excesses (m_4j peaks near 8 TeV and 3.6 TeV with associated dijet resonances at ~2 TeV and 0.95 TeV) arise from production of fourth-generation b' quarks with mass ~2 TeV. These form resonant b'b'b'b' tetraquarks and non-resonant b'b'b'b' states involving b'b' bound states (color-octet vectors with n=1 at 0.95 TeV and scalars with n=2 at 2 TeV) in a Higgs-mediated Yukawa potential. The paper asserts that the b'b' system generates the required spectrum and can be accommodated by mapping to effective theories with color-octet scalars and vectors, analogizing to the X(6900) tetraquark.

Significance. If the bound-state spectrum derivation and data mapping can be made rigorous and independent of the observed peaks, the result would be significant as a concrete BSM interpretation of multiple di-dijet anomalies in terms of fourth-generation quarks and Higgs-Yukawa bound states. It would provide a TeV-scale analog to known tetraquarks and suggest targeted searches in four-jet channels at higher luminosity.

major comments (3)

[Abstract] Abstract: The statement that 'a b'b' system with m_b'≈2 TeV in the Yukawa potential does generate the aforementioned bound state spectrum' is asserted without any derivation, including the explicit form of the potential (Higgs Yukawa strength y_b' and color factor for the octet channel), the Schrödinger equation, or numerical eigenvalues that yield binding energies producing exactly the 0.95 TeV (n=1 vector) and 2 TeV (n=2 scalar) states.
[Abstract] Abstract: The principal quantum numbers (n=1,2), the vector/scalar assignments, and the direct mapping of the observed m_4j and dijet masses onto resonant tetraquark production versus non-resonant bound-state production are chosen to reproduce the reported excesses; by the paper's own construction this reduces the 'spectrum' to a fit of the input data rather than an a priori prediction.
[effective theories discussion] The section translating the model to effective theories with color-octet scalars and vectors: No cross-section estimates, branching ratios, or acceptance calculations are provided to demonstrate quantitative accommodation of the observed excesses, leaving the claim that the excesses 'can be accommodated' at a purely qualitative level.

minor comments (3)

The notation distinguishing the b'b' bound states from the b'b'b'b' tetraquark system should be made explicit to avoid reader confusion.
A table summarizing the mass values, quantum numbers, and corresponding experimental peaks would improve clarity.
Additional references to prior literature on fourth-generation quark bounds and Higgs-mediated potentials would provide better context.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for the careful reading of our manuscript and the constructive comments. We address each major comment below and indicate the revisions we will implement to strengthen the presentation and rigor of the work.

read point-by-point responses

Referee: [Abstract] Abstract: The statement that 'a b'b' system with m_b'≈2 TeV in the Yukawa potential does generate the aforementioned bound state spectrum' is asserted without any derivation, including the explicit form of the potential (Higgs Yukawa strength y_b' and color factor for the octet channel), the Schrödinger equation, or numerical eigenvalues that yield binding energies producing exactly the 0.95 TeV (n=1 vector) and 2 TeV (n=2 scalar) states.

Authors: We agree that the abstract is concise and that the bound-state derivation merits more explicit detail for clarity. The main text does outline the Higgs-mediated Yukawa potential for the color-octet channel and states that the spectrum follows from solving the corresponding Schrödinger equation, but we will expand this into a dedicated subsection (or appendix) that explicitly writes the potential V(r) = - (y_b'^2 / 4π) * (color factor) * exp(-m_H r)/r, specifies the color-octet factor, presents the radial Schrödinger equation, and tabulates the numerical eigenvalues for the n=1 vector and n=2 scalar states at m_b' ≈ 2 TeV that reproduce the quoted binding energies. This will make the claim fully self-contained. revision: yes
Referee: [Abstract] Abstract: The principal quantum numbers (n=1,2), the vector/scalar assignments, and the direct mapping of the observed m_4j and dijet masses onto resonant tetraquark production versus non-resonant bound-state production are chosen to reproduce the reported excesses; by the paper's own construction this reduces the 'spectrum' to a fit of the input data rather than an a priori prediction.

Authors: The quantum-number assignments and state identifications follow from the standard quantum-mechanical structure of a Yukawa potential in the color-octet channel (ground state vector, first radial excitation scalar), which is fixed once m_b' and the Higgs coupling are chosen. The overall mass scale m_b' ≈ 2 TeV is set by the observed dijet resonance positions rather than by the four-jet peaks alone. Nevertheless, we acknowledge that the specific mapping to the reported excesses is data-guided and constitutes an interpretive framework rather than a blind prediction. We will revise the abstract and introduction to state this explicitly, emphasizing that the model provides a consistent explanation of the anomalies within the fourth-generation setup rather than an independent forecast of the peak locations. revision: partial
Referee: [effective theories discussion] The section translating the model to effective theories with color-octet scalars and vectors: No cross-section estimates, branching ratios, or acceptance calculations are provided to demonstrate quantitative accommodation of the observed excesses, leaving the claim that the excesses 'can be accommodated' at a purely qualitative level.

Authors: We concur that the current discussion of effective-theory accommodation remains qualitative. In the revised manuscript we will add order-of-magnitude estimates of the resonant and non-resonant production cross sections at 13 TeV, using the effective couplings and widths already present in the cited color-octet scalar/vector literature. We will also provide branching-ratio estimates for the tetraquark decays into the observed dijet pairs and comment on typical acceptance in the ATLAS/CMS four-jet analyses, thereby converting the accommodation statement into a semi-quantitative one while retaining the focus on the underlying fourth-generation dynamics. revision: yes

Circularity Check

1 steps flagged

Masses, quantum numbers, and bound-state energies chosen to match observed di-dijet peaks, then presented as generated by the Yukawa potential

specific steps

fitted input called prediction [Abstract]
"It is shown that a b'b' system with m_{b'}≈2 TeV in the Yukawa potential does generate the aforementioned bound state spectrum."

The 'aforementioned bound state spectrum' is defined by the observed dijet resonances at ~2 TeV (n=2 scalar) and 0.95 TeV (n=1 vector) that the paper maps onto the LHC excesses. m_b' is selected to place the bound states at those locations, and the Yukawa coupling is implicitly adjusted so the Schrödinger solution reproduces the input masses; the 'showing' is therefore by construction after fitting.

full rationale

The paper postulates m_b'≈2 TeV and assigns n=1,2 states to the specific observed dijet masses (2 TeV and 0.95 TeV) and m_4j peaks. It then states that the chosen m_b' in the Higgs-Yukawa potential 'does generate the aforementioned bound state spectrum.' Because the spectrum values are taken directly from the data and the potential strength (via y_b') is adjustable, the demonstration reduces to a post-hoc consistency check rather than an independent derivation. The central attribution of the excesses therefore rests on a fitted mapping rather than a parameter-free prediction. This is the load-bearing step; other elements (effective-theory translation) are secondary accommodations.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 2 invented entities

The central claim rests on the existence of a fourth generation, a Higgs-mediated Yukawa potential capable of binding color-octet states at the stated masses, and the direct mapping of those states onto the observed excesses; multiple free parameters and new entities are introduced without external calibration.

free parameters (2)

b' quark mass = ~2 TeV
Set to approximately 2 TeV to produce dijet resonances at 2 TeV and 0.95 TeV and four-jet masses at 8 TeV and 3.6 TeV.
principal quantum numbers n=1,2 for bound states
Assigned to match the ground and first excited color-octet states to the reported dijet masses.

axioms (2)

domain assumption Higgs boson exchange generates a Yukawa potential that binds b'b' pairs into color-octet scalars and vectors with the observed spectrum
Invoked to explain how the 2 TeV and 0.95 TeV dijet resonances arise.
ad hoc to paper The LHC excesses are due to fourth-generation quark production rather than other processes
The foundational postulate that attributes the data to b'b'b'b' states.

invented entities (2)

fourth-generation b' quark no independent evidence
purpose: Source of the tetraquark and dijet resonances
Postulated to explain the excesses; no independent evidence provided.
color-octet scalar (n=2) and vector (n=1) bound states no independent evidence
purpose: Dijet resonances at 2 TeV and 0.95 TeV
Invented bound states whose masses are fitted to data.

pith-pipeline@v0.9.0 · 5647 in / 2104 out tokens · 44331 ms · 2026-05-10T18:22:11.658550+00:00 · methodology

discussion (0)

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

IndisputableMonolith/Cost/FunctionalEquation.lean washburn_uniqueness_aczel (J-cost uniqueness) unclear

?

unclear
Relation between the paper passage and the cited Recognition theorem.

We deduce the mass spectrum for b' b-bar states bound by a Yukawa potential V(r) = -α_Y e^{-m_H^* r}/r ... En = ... (Dirac-equation eigenenergy formula with C_s tuned to give m1=0.94 TeV, m2=2.1 TeV)
IndisputableMonolith/Foundation/AbsoluteFloorClosure.lean reality_from_one_distinction unclear

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unclear
Relation between the paper passage and the cited Recognition theorem.

It has been found that heavy fermions ... form bound states in a Yukawa potential created by Higgs boson exchanges

What do these tags mean?

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supports: The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
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contradicts: The paper's claim conflicts with a theorem or certificate in the canon.
unclear: Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Reference graph

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