CMS-PAS-EXO-21-004

CMS-PAS-EXO-21-004
Search for pair-produced multijet resonances using data scouting
CMS Collaboration
1 August 2023

Abstract: Searches for pair-produced multijet signatures are presented. The analyses use a data sample corresponding to an integrated luminosity of 128 fb$ ^{-1} $ of proton-proton collisions at $ \sqrt{s}= $ 13 TeV to measure the average mass distributions of pairs of tri-jets, both merged and resolved, and pairs of merged dijets. The data were collected using data scouting, which saves events with trigger-level reconstruction, enabling the recording of events corresponding to relatively low multi-jet masses. The results are interpreted within an R-parity violating supersymmetric framework in which the pair productions of higgsinos, gluinos, and top squarks are used as benchmark models. Decays to three resolved jets, as well as to highly Lorentz-boosted pairs of two or three quarks yielding single large radius jets, are considered. The search excludes RPV gluinos with mass less than 1.7 TeV, and extends prior exclusions of RPV squarks and gluinos to the low mass region between 70 and 200 GeV. The electroweak production of R-parity violating supersymmetry is probed for the first time in fully hadronic final states, yielding the first exclusions on prompt hadronically decaying mass-degenerate higgsinos.
Links: CDS record (PDF) ; Physics Briefing ; CADI line (restricted) ; These preliminary results are superseded in this paper, Submitted to PRL. The superseded preliminary plots can be found here.

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: Benchmark models from RPV SUSY for resolved trijets (left), merged trijets (middle) and merged dijets (right). The red circles group the final state quarks according to the expected jet clustering of their hadronization products.
png pdf	Figure 1-a: Benchmark models from RPV SUSY for resolved trijets (left), merged trijets (middle) and merged dijets (right). The red circles group the final state quarks according to the expected jet clustering of their hadronization products.
png pdf	Figure 1-b: Benchmark models from RPV SUSY for resolved trijets (left), merged trijets (middle) and merged dijets (right). The red circles group the final state quarks according to the expected jet clustering of their hadronization products.
png pdf	Figure 1-c: Benchmark models from RPV SUSY for resolved trijets (left), merged trijets (middle) and merged dijets (right). The red circles group the final state quarks according to the expected jet clustering of their hadronization products.
png pdf	Figure 2: The distribution of average jet mass in the data (points), for the search for pair-produced boosted resonances decaying to trijets (left) and dijets (right), compared to a background-only prediction from GP regression (blue), and the full background fit including simulations (red) of SM resonances from $ \mathrm{t} \overline{\mathrm{t}} $ (left) and W/Z+jets (right). Also shown are the expected shapes of signals from R-parity violating gluinos with resonance masses 70 (green), 125 (yellow) and 200 GeV (purple).
png pdf	Figure 2-a: The distribution of average jet mass in the data (points), for the search for pair-produced boosted resonances decaying to trijets (left) and dijets (right), compared to a background-only prediction from GP regression (blue), and the full background fit including simulations (red) of SM resonances from $ \mathrm{t} \overline{\mathrm{t}} $ (left) and W/Z+jets (right). Also shown are the expected shapes of signals from R-parity violating gluinos with resonance masses 70 (green), 125 (yellow) and 200 GeV (purple).
png pdf	Figure 2-b: The distribution of average jet mass in the data (points), for the search for pair-produced boosted resonances decaying to trijets (left) and dijets (right), compared to a background-only prediction from GP regression (blue), and the full background fit including simulations (red) of SM resonances from $ \mathrm{t} \overline{\mathrm{t}} $ (left) and W/Z+jets (right). Also shown are the expected shapes of signals from R-parity violating gluinos with resonance masses 70 (green), 125 (yellow) and 200 GeV (purple).
png pdf	Figure 3: The distribution of trijet mass in the data (points), for the three search regions (left, middle and right) for pair-produced resolved resonances decaying to trijets, compared to a background-only fit from GP regression (blue), and (left) the full background fit including simulation of a SM resonance from t tbar production (red). Also shown are the expected shapes of signals from R-parity violating gluinos at various masses (green, yellow and purple).
png pdf	Figure 3-a: The distribution of trijet mass in the data (points), for the three search regions (left, middle and right) for pair-produced resolved resonances decaying to trijets, compared to a background-only fit from GP regression (blue), and (left) the full background fit including simulation of a SM resonance from t tbar production (red). Also shown are the expected shapes of signals from R-parity violating gluinos at various masses (green, yellow and purple).
png pdf	Figure 3-b: The distribution of trijet mass in the data (points), for the three search regions (left, middle and right) for pair-produced resolved resonances decaying to trijets, compared to a background-only fit from GP regression (blue), and (left) the full background fit including simulation of a SM resonance from t tbar production (red). Also shown are the expected shapes of signals from R-parity violating gluinos at various masses (green, yellow and purple).
png pdf	Figure 3-c: The distribution of trijet mass in the data (points), for the three search regions (left, middle and right) for pair-produced resolved resonances decaying to trijets, compared to a background-only fit from GP regression (blue), and (left) the full background fit including simulation of a SM resonance from t tbar production (red). Also shown are the expected shapes of signals from R-parity violating gluinos at various masses (green, yellow and purple).
png pdf	Figure 4: Observed limits (points) and expected limits (dashes) on the product of cross section ($ \sigma $), branching fraction (B), and acceptance (A) for pair produced merged three quark resonances (left), pair produced merged two quark resonances (middle), and pair produced resolved three quark resonances (right). The vertical lines on the resolved three quark resonance limits (right) indicate the different search mass regions. The variations at the one and two standard deviation levels in the expected limits (shaded bands) are also shown. Limits are compared to predictions for three signals of pair production of R-parity violating resonances: gluinos (red in left and right), mass degenerate higgsinos (blue in left), and top squarks (red in middle).
png pdf	Figure 4-a: Observed limits (points) and expected limits (dashes) on the product of cross section ($ \sigma $), branching fraction (B), and acceptance (A) for pair produced merged three quark resonances (left), pair produced merged two quark resonances (middle), and pair produced resolved three quark resonances (right). The vertical lines on the resolved three quark resonance limits (right) indicate the different search mass regions. The variations at the one and two standard deviation levels in the expected limits (shaded bands) are also shown. Limits are compared to predictions for three signals of pair production of R-parity violating resonances: gluinos (red in left and right), mass degenerate higgsinos (blue in left), and top squarks (red in middle).
png pdf	Figure 4-b: Observed limits (points) and expected limits (dashes) on the product of cross section ($ \sigma $), branching fraction (B), and acceptance (A) for pair produced merged three quark resonances (left), pair produced merged two quark resonances (middle), and pair produced resolved three quark resonances (right). The vertical lines on the resolved three quark resonance limits (right) indicate the different search mass regions. The variations at the one and two standard deviation levels in the expected limits (shaded bands) are also shown. Limits are compared to predictions for three signals of pair production of R-parity violating resonances: gluinos (red in left and right), mass degenerate higgsinos (blue in left), and top squarks (red in middle).
png pdf	Figure 4-c: Observed limits (points) and expected limits (dashes) on the product of cross section ($ \sigma $), branching fraction (B), and acceptance (A) for pair produced merged three quark resonances (left), pair produced merged two quark resonances (middle), and pair produced resolved three quark resonances (right). The vertical lines on the resolved three quark resonance limits (right) indicate the different search mass regions. The variations at the one and two standard deviation levels in the expected limits (shaded bands) are also shown. Limits are compared to predictions for three signals of pair production of R-parity violating resonances: gluinos (red in left and right), mass degenerate higgsinos (blue in left), and top squarks (red in middle).

Tables
png pdf	Table 1: Selection requirements for the resolved trijet resonance search are listed for the three regions of gluino mass.
png pdf	Table 2: Summary of the systematic uncertainties in the signal yield and shape for the searches for resolved and merged, three and two quark resonances.\\

Summary

A search has been performed for pair-produced multijet resonances, where the jets in the final state can be either merged or individually resolved. This search observes the hadronic decays of standard model resonances, such as the top quark and W, Z bosons. New, additional resonances were not observed, with the largest effect seen for a resonance mass of 768 GeV, but with a local significance below 3 standard deviations. This search extends the previous limits on R-parity violating models of top squarks and gluinos, and sets the first limits on R-parity violating mass-degenerate, prompt, and hadronically decaying higgsinos.

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