arxiv: 1207.1873 · v1 · pith:ZNW6E4LTnew · submitted 2012-07-08 · ✦ hep-ph · hep-ex

Searching for Top Squarks at the LHC in Fully Hadronic Final State

Bhaskar Dutta , Teruki Kamon , Nikolay Kolev , Kuver Sinha , Kechen Wang This is my paper

Pith reviewed 2026-05-19 05:12 UTC · model grok-4.3

classification ✦ hep-ph hep-ex

keywords top squarkstop searchLHCsupersymmetryfully hadronic final stateM3 variableneutralino

0 comments p. Extension

Add this Pith Number to your LaTeX paper

\usepackage{pith}
\pithnumber{ZNW6E4LT}

Prints a linked pith:ZNW6E4LT badge after your title and writes the identifier into PDF metadata. Compiles on arXiv with no extra files. Learn more

The pith

The M3 kinematic variable reconstructs top-quark pairs from stop decays and reduces the dominant ttbar background until signal and background cross sections become comparable for stop masses of 350-500 GeV at 8 TeV.

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

This paper examines a supersymmetry scenario in which the lighter top squark can be produced at the early LHC while gluinos and first-generation squarks remain heavier. Stops decay to a top quark plus the lightest neutralino, and the search targets the fully hadronic final state. A straightforward kinematic variable, M3, is introduced to reconstruct the two top quarks produced in stop-pair events. After kinematic cuts that exploit missing transverse momentum and lepton identification, the authors show that the residual Standard Model background can be brought down to roughly the same level as the expected signal.

Core claim

In the fully hadronic channel the M3 variable reconstructs the two top quarks arising from stop-pair production; with lepton-veto and missing-energy cuts the dominant ttbar-plus-jets background (containing one undetected lepton) is reduced until signal and background cross sections are comparable for stop masses between 350 and 500 GeV when the neutralino mass is fixed at 100 GeV.

What carries the argument

The M3 variable, a simple kinematic quantity used to reconstruct the two top quarks in fully hadronic stop-pair events.

If this is right

Stops in the 350-500 GeV range become experimentally accessible in the all-hadronic channel already at 8 TeV.
Control of lepton-veto efficiency is essential for background estimation in this topology.
The same reconstruction technique can be applied to other decay modes once more data are collected.

Where Pith is reading between the lines

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

Extending the analysis to 13 TeV data would raise the accessible stop mass reach by several hundred GeV.
The method could be combined with b-tagging or jet-substructure variables to further suppress backgrounds.

Load-bearing premise

Lepton identification efficiencies and the chosen kinematic cuts can be controlled well enough that the residual semileptonic ttbar background does not overwhelm the signal after all selections.

What would settle it

A measurement of the yield in the signal region after the full set of M3 and kinematic cuts that is either significantly above or consistent with the predicted background rate.

read the original abstract

We pursue a scenario where the lighter top squark (stop) mass is accessible for the Large Hadron Collider (LHC) in the near future, while gluinos and first two generation squarks are heavier. At $\sqrt{s} = 8$ TeV, we investigate the identification of stops which decay predominantly into a top quark and the stable lightest supersymmetric particle. We use a simple kinematical variable, $M3$, to reconstruct two top quarks which are pair-produced from the stops, in the fully hadronic channel. The dominant Standard Model (SM) background for this signal stems from $t\bar t$ plus jets, with one top quark decaying into $ bl\nu$, where the lepton is undetected and the $\nu$ produces missing transverse momentum. The lepton identification efficiency is thus crucial in order to estimate the background correctly. We identify kinematical variables to reduce the SM background. We find that it is possible to achieve signal and background cross-section at similar levels for stop masses around $350 - 500$ GeV for a neutralino mass of 100 GeV.

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

The paper sketches a stop search in the fully hadronic channel with the M3 variable but supplies no Monte Carlo numbers or cut flows to support its main claim.

read the letter

The central point here is a proposal to reconstruct pair-produced stops decaying to top plus neutralino using the M3 variable in the all-jets final state at 8 TeV, plus a lepton veto to control the dominant ttbar background. That combination is a reasonable incremental step from existing top-reconstruction methods, and the authors correctly flag that lepton identification efficiency sets the size of the residual background. They also note that kinematic cuts can bring signal and background cross sections into rough parity for stop masses between 350 and 500 GeV when the neutralino is around 100 GeV. Those are the concrete elements that are actually new in the text we have. Everything else rests on Monte Carlo studies that are not shown. There are no efficiencies, no cut-flow tables, and no validation plots for how well the lepton veto and additional kinematic variables suppress semileptonic ttbar. Without those numbers the assertion that S becomes comparable to B cannot be checked, so the mass reach quoted in the abstract remains an unverified expectation. The paper is therefore best read as an outline of a possible analysis strategy rather than a completed result. Readers already running SUSY searches or working on top-tagging variables might find the suggested cuts worth testing, but the work does not yet contain enough detail to stand on its own. I would not send it to referees until the actual simulation results and background modeling checks are included.

Referee Report

1 major / 0 minor

Summary. The manuscript proposes a search for pair-produced light top squarks (stops) decaying to top plus neutralino in the fully hadronic channel at 8 TeV LHC. It introduces the M3 variable to reconstruct the two tops and applies kinematic cuts to suppress the dominant ttbar+jets background (with one lepton undetected), claiming that signal and background cross sections can be made comparable for stop masses 350-500 GeV when the neutralino mass is 100 GeV.

Significance. If the Monte Carlo results hold, the strategy would open a viable fully hadronic channel for early LHC stop searches in a compressed spectrum where gluinos and first-generation squarks are heavy. The emphasis on lepton-veto efficiency and the M3 variable addresses a concrete experimental challenge, but the lack of any quantitative efficiencies, cut-flow tables, or background validation in the provided text prevents verification of the central S~B claim.

major comments (1)

Abstract: the assertion that 'signal and background cross-section at similar levels' for m_stop = 350-500 GeV rests entirely on Monte Carlo results that are not shown. No lepton-identification efficiencies, residual semileptonic ttbar rates after the veto, or post-cut cross sections are provided, so the claim cannot be assessed from the manuscript as given.

Simulated Author's Rebuttal

1 responses · 1 unresolved

We thank the referee for the report and the constructive criticism. The central issue raised is that the abstract claim of comparable signal and background cross sections is not supported by visible quantitative results. Because the provided manuscript text consists solely of the abstract, we cannot reproduce the Monte Carlo numbers or cut-flow tables here; however, the full paper contains the underlying analysis. We will revise the manuscript to make those results more explicit and accessible.

read point-by-point responses

Referee: Abstract: the assertion that 'signal and background cross-section at similar levels' for m_stop = 350-500 GeV rests entirely on Monte Carlo results that are not shown. No lepton-identification efficiencies, residual semileptonic ttbar rates after the veto, or post-cut cross sections are provided, so the claim cannot be assessed from the manuscript as given.

Authors: We agree that the abstract statement would benefit from direct reference to the supporting numbers. In the full manuscript we present the M3-based reconstruction, lepton-veto efficiencies, and the resulting cross sections after all cuts for the quoted mass points. To address the concern we will add a compact cut-flow table (or explicit post-cut cross-section values) to the revised abstract or the opening of the results section so that the S ~ B claim can be evaluated without consulting later figures. revision: yes

standing simulated objections not resolved

Detailed Monte Carlo cut-flow tables and efficiency numbers, which are present in the complete paper but unavailable from the abstract-only text supplied for this response.

Circularity Check

0 steps flagged

No circularity; phenomenological claims rest on external MC simulation

full rationale

The provided text consists solely of an abstract that states a search strategy using the M3 variable plus kinematic cuts and reports an empirical finding that S ~ B can be reached for certain stop/neutralino masses. No derivation, equation, fit, or self-citation chain is present, so none of the enumerated circularity patterns can be exhibited by direct quotation. The result is therefore externally falsifiable via independent Monte Carlo studies and does not reduce to its own inputs by construction.

Axiom & Free-Parameter Ledger

2 free parameters · 0 axioms · 0 invented entities

The analysis assumes standard LHC detector response, standard SUSY decay branching ratios, and that the dominant background is ttbar+jets with one lost lepton; no new particles or forces are postulated beyond the MSSM stop and neutralino already named.

free parameters (2)

stop mass
Scanned in the 350-500 GeV window to find where signal becomes comparable to background.
neutralino mass
Fixed at 100 GeV for the quoted reach.

pith-pipeline@v0.9.0 · 5714 in / 1241 out tokens · 17901 ms · 2026-05-19T05:12:44.809214+00:00 · methodology