CMS-PAS-SUS-18-007

CMS-PAS-SUS-18-007
Search for supersymmetry using Higgs boson to diphoton decays at $\sqrt{s} =$ 13 TeV with the CMS detector
CMS Collaboration
May 2019

Abstract: A search for supersymmetry is presented where at least one Higgs boson is produced and decays to two photons in the decay chains of the pair-produced supersymmetric particles. The presence of charged leptons and additional Higgs boson candidates and various kinematic variables are used to categorize events into search regions which are sensitive to different supersymmetry scenarios. The results are based on data from proton-proton collisions at the Large Hadron Collider at a center of mass energy of 13 TeV collected by the CMS experiment in 2016 and 2017, corresponding to 77.5 fb $^{-1}$ . No statistically significant excess of events is observed relative to standard model expectations. We exclude bottom squark pair production for bottom squark masses below 530 GeV and an LSP mass of 1 GeV; wino-like chargino-neutralino production for chargino and neutralino masses below 235 GeV with gravitino masses of 1 GeV; and higgsino-like chargino-neutralino production for neutralino masses below 290 GeV, for the case where the neutralino decays to a Higgs boson and a gravitino 100% of the time.
Links: CDS record (PDF) ; CADI line (restricted) ; These preliminary results are superseded in this paper, JHEP 11 (2019) 109. The superseded preliminary plots can be found here.

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: Diagrams displaying the simplified models that are being considered. Upper left: bottom squark pair production; upper right: wino-like chargino-neutralino production; bottom: the two relevant decay modes for higgsino-like neutralino pair production in the GMSB scenario.
png pdf	Figure 1-a: Diagram displaying bottom squark pair production.
png pdf	Figure 1-b: Diagram displaying wino-like chargino-neutralino production.
png pdf	Figure 1-c: Diagram displaying higgsino-like neutralino pair production in the GMSB scenario.
png pdf	Figure 1-d: Diagram displaying higgsino-like neutralino pair production in the GMSB scenario.
png pdf	Figure 2: The diphoton mass distribution for one example search bin is shown with the background-only fit (left) and the signal-plus-background fit (right) to illustrate the signal extraction procedure. The red dot-dashed curve represents the fitted background prediction; the green dashed curve represents the best-fit signal; and the blue solid curve represents the sum of the best-fit signal and the background. The search region bin shown corresponds to the bin with ${M_{\mathrm {R}}} >$ 150 GeV and ${R^2} >$ 0.08 in the $\mathrm{H} \to \mathrm{b\bar{b}}$ category of the EWP analysis.
png pdf	Figure 2-a: The diphoton mass distribution for one example search bin is shown with the background-only fit to illustrate the signal extraction procedure. The red dot-dashed curve represents the fitted background prediction; the green dashed curve represents the best-fit signal; and the blue solid curve represents the sum of the best-fit signal and the background. The search region bin shown corresponds to the bin with ${M_{\mathrm {R}}} >$ 150 GeV and ${R^2} >$ 0.08 in the $\mathrm{H} \to \mathrm{b\bar{b}}$ category of the EWP analysis.
png pdf	Figure 2-b: The diphoton mass distribution for one example search bin is shown with the signal-plus-background fit to illustrate the signal extraction procedure. The red dot-dashed curve represents the fitted background prediction; the green dashed curve represents the best-fit signal; and the blue solid curve represents the sum of the best-fit signal and the background. The search region bin shown corresponds to the bin with ${M_{\mathrm {R}}} >$ 150 GeV and ${R^2} >$ 0.08 in the $\mathrm{H} \to \mathrm{b\bar{b}}$ category of the EWP analysis.
png pdf	Figure 3: The observed 95% CL upper limits on the bottom squark pair production cross section are shown for the EWP (left) and STP (right) analyses. The solid and dotted black contours represent the observed exclusion region and its $\pm$ 1 standard deviations (1 $\sigma$ ) of their experimental and theoretical uncertainties, while the analogous red contours represent the expected exclusion region and its 1 $\sigma$ band.
png pdf	Figure 3-a: The observed 95% CL upper limits on the bottom squark pair production cross section are shown for the EWP analysis. The solid and dotted black contours represent the observed exclusion region and its $\pm$ 1 standard deviations (1 $\sigma$ ) of their experimental and theoretical uncertainties, while the analogous red contours represent the expected exclusion region and its 1 $\sigma$ band.
png pdf	Figure 3-b: The observed 95% CL upper limits on the bottom squark pair production cross section are shown for the STP analysis. The solid and dotted black contours represent the observed exclusion region and its $\pm$ 1 standard deviations (1 $\sigma$ ) of their experimental and theoretical uncertainties, while the analogous red contours represent the expected exclusion region and its 1 $\sigma$ band.
png pdf	Figure 4: The observed 95% CL upper limits on the wino-like chargino-neutralino production cross section are shown for the EWP (left) and STP (right) analyses. The solid and dotted black contours represent the observed exclusion region and its $\pm$ 1 standard deviations (1 $\sigma$ ) of their experimental and theoretical uncertainties, while the analogous red contours represent the expected exclusion region and its 1 $\sigma$ band.
png pdf	Figure 4-a: The observed 95% CL upper limits on the wino-like chargino-neutralino production cross section are shown for the EWP analysis. The solid and dotted black contours represent the observed exclusion region and its $\pm$ 1 standard deviations (1 $\sigma$ ) of their experimental and theoretical uncertainties, while the analogous red contours represent the expected exclusion region and its 1 $\sigma$ band.
png pdf	Figure 4-b: The observed 95% CL upper limits on the wino-like chargino-neutralino production cross section are shown for the STP analysis. The solid and dotted black contours represent the observed exclusion region and its $\pm$ 1 standard deviations (1 $\sigma$ ) of their experimental and theoretical uncertainties, while the analogous red contours represent the expected exclusion region and its 1 $\sigma$ band.
png pdf	Figure 5: The observed 95% CL upper limits on the production cross section for higgsino-like chargino-neutralino production are shown for the EWP (left) and STP (right) analyses. The charginos and neutralinos undergo several cascade decays producing either Higgs bosons. We present limits in the scenario where the branching fraction of the $\tilde{\chi}^0_1 \to \mathrm{H} \tilde{\mathrm{G}}$ decay is 100%. The dotted and solid black curves represent the expected and observed exclusion region, and the green and yellow bands represent the $\pm$ 1 and $\pm$ 2 standard deviation regions, respectively. The red solid and dotted lines show the theoretical production cross section and its uncertainty band.
png pdf	Figure 5-a: The observed 95% CL upper limits on the production cross section for higgsino-like chargino-neutralino production are shown for the EWP analysis. The charginos and neutralinos undergo several cascade decays producing either Higgs bosons. We present limits in the scenario where the branching fraction of the $\tilde{\chi}^0_1 \to \mathrm{H} \tilde{\mathrm{G}}$ decay is 100%. The dotted and solid black curves represent the expected and observed exclusion region, and the green and yellow bands represent the $\pm$ 1 and $\pm$ 2 standard deviation regions, respectively. The red solid and dotted lines show the theoretical production cross section and its uncertainty band.
png pdf	Figure 5-b: The observed 95% CL upper limits on the production cross section for higgsino-like chargino-neutralino production are shown for the STP analysis. The charginos and neutralinos undergo several cascade decays producing either Higgs bosons. We present limits in the scenario where the branching fraction of the $\tilde{\chi}^0_1 \to \mathrm{H} \tilde{\mathrm{G}}$ decay is 100%. The dotted and solid black curves represent the expected and observed exclusion region, and the green and yellow bands represent the $\pm$ 1 and $\pm$ 2 standard deviation regions, respectively. The red solid and dotted lines show the theoretical production cross section and its uncertainty band.
png pdf	Figure 6: The observed 95% CL upper limits on the production cross section for higgsino-like chargino-neutralino production are shown for the EWP (left) and STP (right) analyses. The charginos and neutralinos undergo several cascade decays producing a Higgs boson and a Z boson. We present limits in the scenario where the branching fraction of the $\tilde{\chi}^0_1 \to \mathrm{H} \tilde{\mathrm{G}}$ and $\tilde{\chi}^0_1 \to {\mathrm{Z}} \tilde{\mathrm{G}}$ decays are each 50% (left). The dotted and solid black curves represent the expected and observed exclusion region, and the green and yellow bands represent the $\pm$ 1 and $\pm$ 2 standard deviation regions, respectively. The red solid and dotted lines show the theoretical production cross section and its uncertainty band.
png pdf	Figure 6-a: The observed 95% CL upper limits on the production cross section for higgsino-like chargino-neutralino production are shown for the EWP analysis. The charginos and neutralinos undergo several cascade decays producing a Higgs boson and a Z boson. We present limits in the scenario where the branching fraction of the $\tilde{\chi}^0_1 \to \mathrm{H} \tilde{\mathrm{G}}$ and $\tilde{\chi}^0_1 \to {\mathrm{Z}} \tilde{\mathrm{G}}$ decays are each 50% (left). The dotted and solid black curves represent the expected and observed exclusion region, and the green and yellow bands represent the $\pm$ 1 and $\pm$ 2 standard deviation regions, respectively. The red solid and dotted lines show the theoretical production cross section and its uncertainty band.
png pdf	Figure 6-b: The observed 95% CL upper limits on the production cross section for higgsino-like chargino-neutralino production are shown for the STP analysis. The charginos and neutralinos undergo several cascade decays producing a Higgs boson and a Z boson. We present limits in the scenario where the branching fraction of the $\tilde{\chi}^0_1 \to \mathrm{H} \tilde{\mathrm{G}}$ and $\tilde{\chi}^0_1 \to {\mathrm{Z}} \tilde{\mathrm{G}}$ decays are each 50% (left). The dotted and solid black curves represent the expected and observed exclusion region, and the green and yellow bands represent the $\pm$ 1 and $\pm$ 2 standard deviation regions, respectively. The red solid and dotted lines show the theoretical production cross section and its uncertainty band.

Tables
png pdf	Table 1: A summary of the search region bins used for the EWP analysis is presented along with the requirements on ${p_{\mathrm {T}}} ^{\gamma \gamma}$ , ${M_{\mathrm {R}}}$ , and ${R^2}$ for each bin.
png pdf	Table 2: Summary of exclusive search regions for the STP analysis. The symbol "-" means that the region is not further split.
png pdf	Table 3: Summary of systematic uncertainties on the SM Higgs background and signal yield predictions, and the size of their effect on the signal yield.
png pdf	Table 4: The observed data, fitted nonresonant background yields, and SM Higgs boson background yields within the mass window between 122 and 129 GeV are shown for each search region bin of the EWK analysis. The category that each search region bin belongs to is also indicated in the table.
png pdf	Table 5: The observed data, fitted nonresonant background yields, and SM Higgs boson background yields within the mass window between 122 and 129 GeV are shown for each search region bin in the $\mathrm{H} \to \mathrm{b\bar{b}}$ , $\mathrm{Z} \to \mathrm{b\bar{b}}$ , and leptonic categories of the STP analysis.
png pdf	Table 6: The observed data, fitted nonresonant background yields, and SM Higgs boson background yields within the mass window between 122 and 129 GeV are shown for each search region bin in the all-hadronic categories of the STP analysis.
png pdf	Table 7: The expected signal yields for the SUSY simplified model signals considered are shown for each search region bin of the EWP analysis. The category that each search region bin belongs to is also indicated in the table. The label HH and ZH refer to the signal models for higgsino-like chargino and neutralino production where the branching fractions of the decays $\tilde{\chi}^0_1 \to \mathrm{H} \tilde{\mathrm{G}}$ and $\tilde{\chi}^0_1 \to {\mathrm{Z}} \tilde{\mathrm{G}}$ are 100% and 0%, and 50% and 50%, respectively. For the above two scenarios, the mass of the chargino and next-to-lightest neutralino is 175 GeV, while the LSP mass is 45 GeV. The label WH(200,1) refers to the signal model for wino-like chargino and neutralino production, where the mass of the chargino and next-to-lightest neutralino is 200 GeV and the LSP mass is 1 GeV. The labels $\tilde{\mathrm{b}}$ (450,1) and $\tilde{\mathrm{b}}$ (450,300) refer to the signal models for bottom squark pair production where the bottom squark mass is 450 GeV and the LSP mass is 1 and 300 GeV, respectively.
png pdf	Table 8: The expected signal yields for the SUSY simplified model signals considered are shown for each search region bin in the $\mathrm{H} \to \mathrm{b\bar{b}}$ , $\mathrm{Z} \to \mathrm{b\bar{b}}$ , and leptonic categories of the STP analysis. The labels for the different signal models are explained in detail in the captions of Table 7.
png pdf	Table 9: The expected signal yields for the SUSY simplified model signals considered are shown for each search region bin in the all-hadronic categories of the STP analysis. The labels for the different signal models are explained in detail in the captions of Table 7.

Summary

We have presented a search for supersymmetry in the final state with a Higgs decaying to a photon pair, using data collected with the CMS detector at the LHC in 2016 and 2017, corresponding to 77.5 fb

$^{-1}$ . Photon pairs in the central part of the detector are considered to reconstruct the Higgs boson. Charged leptons and b jets are used to tag the decay products of an additional boson, while kinematic quantities such as the Razor variables

${M_{\mathrm{R}}}$ and

${R^2}$ , and

${M_{\mathrm{T2}}}$ are used to suppress standard model backgrounds. Data driven fits determine the shape of the non-resonant background. The resonant background from standard model Higgs boson production is estimated from simulation. The results are interpreted in terms of exclusion limits on: the production cross section of bottom squark pair production, ruling out bottom squark masses below 530 GeV for an LSP mass of 1 GeV; wino-like chargino-neutralino production, ruling out masses of up to 235 GeV for an LSP mass of 1 GeV; and higgsino-like chargino-neutralino production, ruling out masses of up to 290 GeV and 230 GeV for the cases where the branching fraction of the

$\tilde{\chi}^0_1\to \mathrm{H}\tilde{\mathrm{G}}$ decay is 100%, and where the branching fractions of the

$\tilde{\chi}^0_1\to \mathrm{H}\tilde{\mathrm{G}}$ and

$\tilde{\chi}^0_1\to \mathrm{Z}\tilde{\mathrm{G}}$ decays are both 50%, respectively.

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