CMS-PAS-EXO-23-004

CMS-PAS-EXO-23-004
Search for dijet resonances with data scouting in proton-proton collisions at $\sqrt{s}=$ 13 TeV
CMS Collaboration
27 March 2025

Abstract: A search is presented for resonances decaying to dijet final states in proton-proton collisions at $\sqrt{s}=$ 13 TeV. This search, for narrow resonances with a mass between 0.6 and 1.8 TeV, is performed using dijets that are reconstructed from calorimeter information in the trigger, in so-called data scouting, from data corresponding to an integrated luminosity of 117.1 fb $^{-1}$ . The dijet mass spectra are well described by a smooth parameterization and no significant evidence for the production of new particles is observed. Generic upper limits are presented on the product of the cross section, the branching fraction, and the acceptance for narrow quark-quark, quark-gluon, and gluon-gluon resonances, and are compared to the predictions from a variety of models of narrow dijet resonance production. The upper limits at 95% confidence level on the coupling strength of a dark matter mediator are presented as a function of the mediator mass. These limits are significantly more constraining than those previously published by CMS.
Links: CDS record (PDF) ; CADI line (restricted) ;

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: The measured HLT trigger efficiency (points) as a function of dijet mass for wide jets, defined in next section, for 2016 (left), 2017 (middle) and 2018 (right) data.
png pdf	Figure 1-a: The measured HLT trigger efficiency (points) as a function of dijet mass for wide jets, defined in next section, for 2016 (left), 2017 (middle) and 2018 (right) data.
png pdf	Figure 1-b: The measured HLT trigger efficiency (points) as a function of dijet mass for wide jets, defined in next section, for 2016 (left), 2017 (middle) and 2018 (right) data.
png pdf	Figure 1-c: The measured HLT trigger efficiency (points) as a function of dijet mass for wide jets, defined in next section, for 2016 (left), 2017 (middle) and 2018 (right) data.
png pdf	Figure 2: Signal shapes of narrow resonances with a mass of 0.6, 1.2, and 1.8 TeV. The reconstructed dijet mass spectra are for wide jets from the PYTHIA8.205 MC event generator including simulation of the CMS detector.
png pdf	Figure 3: Dijet mass spectra (points) compared to a fitted parameterization of the background (solid curve) for the 2016 (top-left), 2017 (top-right), 2018 (bottom-left), and full Run 2 (bottom-right) datasets. The horizontal lines on the data points in the upper panel show variable bin sizes, while the up and down variation in the bottom panels show the bin-by-bin difference between the data and fit, normalized to the total uncertainty.
png pdf	Figure 3-a: Dijet mass spectra (points) compared to a fitted parameterization of the background (solid curve) for the 2016 (top-left), 2017 (top-right), 2018 (bottom-left), and full Run 2 (bottom-right) datasets. The horizontal lines on the data points in the upper panel show variable bin sizes, while the up and down variation in the bottom panels show the bin-by-bin difference between the data and fit, normalized to the total uncertainty.
png pdf	Figure 3-b: Dijet mass spectra (points) compared to a fitted parameterization of the background (solid curve) for the 2016 (top-left), 2017 (top-right), 2018 (bottom-left), and full Run 2 (bottom-right) datasets. The horizontal lines on the data points in the upper panel show variable bin sizes, while the up and down variation in the bottom panels show the bin-by-bin difference between the data and fit, normalized to the total uncertainty.
png pdf	Figure 3-c: Dijet mass spectra (points) compared to a fitted parameterization of the background (solid curve) for the 2016 (top-left), 2017 (top-right), 2018 (bottom-left), and full Run 2 (bottom-right) datasets. The horizontal lines on the data points in the upper panel show variable bin sizes, while the up and down variation in the bottom panels show the bin-by-bin difference between the data and fit, normalized to the total uncertainty.
png pdf	Figure 3-d: Dijet mass spectra (points) compared to a fitted parameterization of the background (solid curve) for the 2016 (top-left), 2017 (top-right), 2018 (bottom-left), and full Run 2 (bottom-right) datasets. The horizontal lines on the data points in the upper panel show variable bin sizes, while the up and down variation in the bottom panels show the bin-by-bin difference between the data and fit, normalized to the total uncertainty.
png pdf	Figure 4: The observed 95% CL upper limits on the product of the cross section ( $\sigma$ ), branching fraction ( $B$ ), and acceptance ( $A$ ) for dijet resonances decaying to quark-quark (left), quark-gluon (middle), gluon-gluon (right). The corresponding expected limits (dashed) and their variations at the 1 and 2 standard deviation levels (shaded bands) are also shown. Limits are compared to predicted cross sections for color-octet scalars with coupling $k_{s}^{2}=1/ 2$ [1], excited quarks [4,5], axigluons [6], colorons [8], scalar diquarks [3], new gauge bosons $\mathrm{W^{'}}$ and $\mathrm{Z}^{'}$ with SM-like couplings [9], and dark matter mediators for coupling $g_{\mathrm{q}}'=$ 0.25 and $m_{\text{DM}}=$ 1 GeV [14,13].
png pdf	Figure 4-a: The observed 95% CL upper limits on the product of the cross section ( $\sigma$ ), branching fraction ( $B$ ), and acceptance ( $A$ ) for dijet resonances decaying to quark-quark (left), quark-gluon (middle), gluon-gluon (right). The corresponding expected limits (dashed) and their variations at the 1 and 2 standard deviation levels (shaded bands) are also shown. Limits are compared to predicted cross sections for color-octet scalars with coupling $k_{s}^{2}=1/ 2$ [1], excited quarks [4,5], axigluons [6], colorons [8], scalar diquarks [3], new gauge bosons $\mathrm{W^{'}}$ and $\mathrm{Z}^{'}$ with SM-like couplings [9], and dark matter mediators for coupling $g_{\mathrm{q}}'=$ 0.25 and $m_{\text{DM}}=$ 1 GeV [14,13].
png pdf	Figure 4-b: The observed 95% CL upper limits on the product of the cross section ( $\sigma$ ), branching fraction ( $B$ ), and acceptance ( $A$ ) for dijet resonances decaying to quark-quark (left), quark-gluon (middle), gluon-gluon (right). The corresponding expected limits (dashed) and their variations at the 1 and 2 standard deviation levels (shaded bands) are also shown. Limits are compared to predicted cross sections for color-octet scalars with coupling $k_{s}^{2}=1/ 2$ [1], excited quarks [4,5], axigluons [6], colorons [8], scalar diquarks [3], new gauge bosons $\mathrm{W^{'}}$ and $\mathrm{Z}^{'}$ with SM-like couplings [9], and dark matter mediators for coupling $g_{\mathrm{q}}'=$ 0.25 and $m_{\text{DM}}=$ 1 GeV [14,13].
png pdf	Figure 4-c: The observed 95% CL upper limits on the product of the cross section ( $\sigma$ ), branching fraction ( $B$ ), and acceptance ( $A$ ) for dijet resonances decaying to quark-quark (left), quark-gluon (middle), gluon-gluon (right). The corresponding expected limits (dashed) and their variations at the 1 and 2 standard deviation levels (shaded bands) are also shown. Limits are compared to predicted cross sections for color-octet scalars with coupling $k_{s}^{2}=1/ 2$ [1], excited quarks [4,5], axigluons [6], colorons [8], scalar diquarks [3], new gauge bosons $\mathrm{W^{'}}$ and $\mathrm{Z}^{'}$ with SM-like couplings [9], and dark matter mediators for coupling $g_{\mathrm{q}}'=$ 0.25 and $m_{\text{DM}}=$ 1 GeV [14,13].
png pdf	Figure 5: Local p-value, and the corresponding significance in standard deviations ( $\sigma$ ), for quark-quark (left), quark-gluon (middle), and gluon-gluon (right) resonances.
png pdf	Figure 5-a: Local p-value, and the corresponding significance in standard deviations ( $\sigma$ ), for quark-quark (left), quark-gluon (middle), and gluon-gluon (right) resonances.
png pdf	Figure 5-b: Local p-value, and the corresponding significance in standard deviations ( $\sigma$ ), for quark-quark (left), quark-gluon (middle), and gluon-gluon (right) resonances.
png pdf	Figure 5-c: Local p-value, and the corresponding significance in standard deviations ( $\sigma$ ), for quark-quark (left), quark-gluon (middle), and gluon-gluon (right) resonances.
png pdf	Figure 6: The 95% CL upper limits on the universal quark coupling $g_{\mathrm{q}}'$ as a function of resonance mass for a leptophobic $\mathrm{Z}^{'}$ resonance that only couples to quarks. The observed limits (solid), expected limits (dashed), and their variation at the 1 and 2 standard deviation levels (shaded bands) are shown. Current limits (black) are compared with previously published ones from CMS at 8 TeV [36] (blue) and at 13 TeV [17] (red).

Tables
png pdf	Table 1: Summary of constraints associated to systematic uncertainty nuisance parameters.

Summary

We have used calorimeter jets from data scouting to search for dijet resonances with masses between 0.6 and 1.8 TeV. The dijet mass spectra are observed to be smoothly falling distributions, and there is no significant evidence for resonant particle production. Signal significances and upper limits are presented, as a function of resonance mass, on the product of the cross section, the branching fraction, and the acceptance for narrow quark-quark, quark-gluon, and gluon-gluon resonances that are applicable to any model of narrow dijet resonance production. The largest local significance is 2.2 standard deviations at a quark-quark resonance mass of 0.8 TeV. The limits exclude models of color-octet scalars, excited quarks, axigluons, colorons, scalar diquarks,

$\mathrm{W^{'}}$ and

$\mathrm{Z}^{'}$ bosons, and dark mater mediators, for benchmark choices of the coupling, over the complete mass range considered. The limits on the coupling to quarks of both vector and axial-vector mediators, in a simplified model of interactions between quarks and dark matter, are also presented as functions of dark matter mass. The current limits significantly extend previously reported limits in the dijet channel.

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