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CMS-PAS-SUS-16-023
Search for supersymmetry in final states with at least one photon and $E_{\mathrm{T}}^{\text{miss}}$ in pp collisions at $\sqrt{s}=$ 13 TeV
Abstract: A search for electroweak production of gauginos is presented using the first LHC Run II data at a center-of-mass energy of 13 TeV. The used data set has been recorded with the CMS detector and corresponds to an integrated luminosity of 2.3 fb$^{-1}$. In gauge-mediated supersymmetry breaking (GMSB) models the gauginos can decay to photons, or other standard model bosons, and gravitinos. The final state considered in this search is characterized by photons and missing transverse energy. Since in electroweak production scenarios the expected hadronic activity is low compared to strong production, no jet requirements are used. Additionally, gluino pair production models are considered, where the analysis does not lose sensitivity in scenarios with compressed mass spectra. The observed data are in agreement with the standard model prediction and limits are set on different models of GMSB.
Figures & Tables Summary References CMS Publications
Figures

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Figure 1:
Feynman diagram of the dominant ${\tilde{\chi}^\pm _{1}} - {\tilde{\chi}^{0}_{2}}$ production mechanism and a typical decay chain in scenarios with a bino-like ${\tilde{\chi}^{0}_{1}}$ and wino-like ${\tilde{\chi}^{0}_{2}}$ and ${\tilde{\chi}^\pm _{1}} $.

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Figure 2:
Feynman diagram corresponding to the TChiWg simplified model.

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Figure 3-a:
Feynman diagrams of the T5gg (a) and T5Wg (b) simplified models.

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Figure 3-b:
Feynman diagrams of the T5gg (a) and T5Wg (b) simplified models.

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Figure 4:
Sketch of the control (CR) and signal region (SR) definitions. The validation region (VR) is not defined in the ${\mathcal {S}}- {M_\mathrm {T}}$ plane, but embedded in the SR with the additional condition $ { S_\mathrm {T}^{ {\gamma }}}<$ 600 GeV. This corresponds approximately to the bottom-left corner of the SR, which is therefore illustrated as a blurred region.

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Figure 5-a:
The ${\mathcal {S}}$ and ${M_\mathrm {T}}$ distributions after the preselection. The overflow is contained in the last bin shown and the bin contents are divided by the bin widths.

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Figure 5-b:
The ${\mathcal {S}}$ and ${M_\mathrm {T}}$ distributions after the preselection. The overflow is contained in the last bin shown and the bin contents are divided by the bin widths.

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Figure 6:
Template fit result: The post-fit distributions for ($\gamma +$)jets and V($+\gamma $) together with the total fit distribution stacked onto the fixed backgrounds. Events containing zero jets are counted in the last shown bin. The values in the legend are the resulting scale factors.

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Figure 7-a:
Comparison of the total background prediction to data in the control region without a b-jet veto. a,b: ${E_{\mathrm {T}}^{\text {miss}}} $ significance (a) and transverse mass (b). c,d: ${ S_\mathrm {T}^{ {\gamma }}}$ (c) and leading photon ${p_{\mathrm {T}}} $ (d). The overflow is contained in the last bin. The bin contents are divided by the bin widths.

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Figure 7-b:
Comparison of the total background prediction to data in the control region without a b-jet veto. a,b: ${E_{\mathrm {T}}^{\text {miss}}} $ significance (a) and transverse mass (b). c,d: ${ S_\mathrm {T}^{ {\gamma }}}$ (c) and leading photon ${p_{\mathrm {T}}} $ (d). The overflow is contained in the last bin. The bin contents are divided by the bin widths.

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Figure 7-c:
Comparison of the total background prediction to data in the control region without a b-jet veto. a,b: ${E_{\mathrm {T}}^{\text {miss}}} $ significance (a) and transverse mass (b). c,d: ${ S_\mathrm {T}^{ {\gamma }}}$ (c) and leading photon ${p_{\mathrm {T}}} $ (d). The overflow is contained in the last bin. The bin contents are divided by the bin widths.

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Figure 7-d:
Comparison of the total background prediction to data in the control region without a b-jet veto. a,b: ${E_{\mathrm {T}}^{\text {miss}}} $ significance (a) and transverse mass (b). c,d: ${ S_\mathrm {T}^{ {\gamma }}}$ (c) and leading photon ${p_{\mathrm {T}}} $ (d). The overflow is contained in the last bin. The bin contents are divided by the bin widths.

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Figure 8-a:
Comparison of the total background prediction to data in the control region with the additional requirement of exactly one lepton. a: missing transverse energy. b: ${E_{\mathrm {T}}^{\text {miss}}}$ significance. The overflow is contained in the last bin. The bin contents are divided by the bin widths.

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Figure 8-b:
Comparison of the total background prediction to data in the control region with the additional requirement of exactly one lepton. a: missing transverse energy. b: ${E_{\mathrm {T}}^{\text {miss}}}$ significance. The overflow is contained in the last bin. The bin contents are divided by the bin widths.

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Figure 9-a:
Comparison of the total background prediction to data in the validation region. a: leading photon ${p_{\mathrm {T}}} $. b: ${ S_\mathrm {T}^{ {\gamma }}}$. The overflow is contained in the last bin. The bin contents are divided by the bin widths.

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Figure 9-b:
Comparison of the total background prediction to data in the validation region. a: leading photon ${p_{\mathrm {T}}} $. b: ${ S_\mathrm {T}^{ {\gamma }}}$. The overflow is contained in the last bin. The bin contents are divided by the bin widths.

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Figure 10:
Background and data distributions in the signal region using the final binning in ${ S_\mathrm {T}^{ {\gamma }}}$. The last bin contains the overflow. The background and signal histograms are stacked.

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Figure 11:
The 95% CL limits for the GGM model in the bino-wino mass plane. The color scale encodes the observed upper cross section limit for each point. The lines represent the observed (black) and expected (red) exclusion contours and their uncertainties.

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Figure 12:
Observed and expected upper cross section limits as a function of the NLSP mass for the TChiWg model together with the theoretical cross section.

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Figure 13:
The 95% CL limits for the T5gg model in the gluino-neutralino mass plane. The color scale encodes the observed upper cross section limit for each point. The lines represent the observed (black) and expected (red) exclusion contours and their uncertainties.

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Figure 14:
The 95% CL limits for the T5Wg model in the gluino-neutralino mass plane. The color scale encodes the observed upper cross section limit for each point. The lines represent the observed (black) and expected (red) exclusion contours and their uncertainties.
Tables

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Table 1:
Systematic uncertainties of the separate backgrounds. The uncertainties are relative to the respective backgrounds.

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Table 2:
Yields for the individual SR bins. For the total systematic uncertainties the correlation term for the systematic uncertainties of ${\mathrm {V}(+ {\gamma })}$ and ${( {\gamma }+)\text {jets}}$ has been considered.

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Table 3:
Individual background yields for the separate signal region bins. The statistical uncertainty of the ${ {\mathrm {e}}\to {\gamma }}$ background is due to the limited size of the collected data sample. All other statistical uncertainties are due to the limited number of simulated events.
Summary
A search for the production of supersymmetric particles decaying to photons is presented. The data sample used corresponds to 2.3 fb$^{-1}$ of pp collisions recorded with the CMS detector in 2015 at $ \sqrt{s} = $ 13 TeV. A cut-and-count experiment is performed in three exclusive search bins. The observed event counts are in agreement with the SM prediction. Exclusion limits at the 95% CL are set for a general gauge mediation model of electroweak production and the simplified model TChiWg. The limits for the electroweak production models cannot be improved with respect to the 8 TeV search. A much larger sensitivity is expected with more integrated luminosity collected at $ \sqrt{s} = $ 13 TeV. Additionally, limits are set for two simplified models (T5gg, T5Wg) assuming gluino pair production. The currently best CMS limits are improved in regions with large NLSP masses.
References
1 P. Ramond Dual theory for free fermions PRD 3 (1971) 2415
2 J. Wess and B. Zumino Supergauge transformations in four-dimensions Nucl. Phys. B 70 (1974) 39
3 D. Z. Freedman, P. van Nieuwenhuizen, and S. Ferrara Progress toward a theory of supergravity PRD 13 (1976) 3214
4 P. Fayet Supergauge invariant extension of the Higgs mechanism and a model for the electron and its neutrino Nucl. Phys. B 90 (1975) 104
5 A. H. Chamseddine, R. L. Arnowitt, and P. Nath Locally supersymmetric grand unification PRL 49 (1982) 970
6 L. J. Hall, J. D. Lykken, and S. Weinberg Supergravity as the messenger of supersymmetry breaking PRD 27 (1983) 2359
7 G. L. Kane, C. F. Kolda, L. Roszkowski, and J. D. Wells Study of constrained minimal supersymmetry PRD 49 (1994) 6173 hep-ph/9312272
8 R. Barbieri and G. F. Giudice Upper bounds on supersymmetric particle masses Nucl. Phys. B 306 (1988) 63
9 P. Fayet Mixing between gravitational and weak interactions through the massive gravitino PLB 70 (1977) 461
10 H. Baer, M. Brhlik, C. H. Chen, and X. Tata Signals for the minimal gauge-mediated supersymmetry breaking model at the Fermilab Tevatron collider PRD 55 (1997) 4463 hep-ph/9610358
11 H. Baer, P. G. Mercadante, X. Tata, and Y. L. Wang Reach of Tevatron upgrades in gauge-mediated supersymmetry breaking models PRD 60 (1999) 055001 hep-ph/9903333
12 S. Dimopoulos, S. Thomas, and J. D. Wells Sparticle spectroscopy and electroweak symmetry breaking with gauge-mediated supersymmetry breaking Nucl. Phys. B 488 (1997) 39 hep-ph/9609434
13 J. R. Ellis, J. L. Lopez, and D. V. Nanopoulos Analysis of LEP constraints on supersymmetric models with a light gravitino PLB 394 (1997) 354 hep-ph/9610470
14 M. Dine, A. E. Nelson, Y. Nir, and Y. Shirman New tools for low energy dynamical supersymmetry breaking PRD 53 (1996) 2658 hep-ph/9507378
15 G. F. Giudice and R. Rattazzi Gauge-mediated supersymmetry breaking in Perspectives on supersymmetry, p. 355 World Scientific, Singapore
16 R. Barbier et al. R-parity violating supersymmetry Phys.Rept. 420 (2005) 1 hep-ph/0406039
17 G. R. Farrar and P. Fayet Phenomenology of the production, decay, and detection of new hadronic states associated with supersymmetry PLB 76 (1978) 575
18 P. Meade, N. Seiberg, and D. Shih General gauge mediation Prog. Theor. Phys. Suppl. 177 (2009) 143 0801.3278
19 M. Buican, P. Meade, N. Seiberg, and D. Shih Exploring general gauge mediation JHEP 03 (2009) 016 0812.3668
20 J. T. Ruderman and D. Shih General neutralino NLSPs at the early LHC JHEP 08 (2012) 159 1103.6083
21 Y. Kats, P. Meade, M. Reece, and D. Shih The status of GMSB after 1/fb at the LHC JHEP 02 (2012) 115 1110.6444
22 Y. Kats and M. J. Strassler Probing colored particles with photons, leptons, and jets JHEP 11 (2012) 097 1204.1119
23 P. Grajek, A. Mariotti, and D. Redigolo Phenomenology of general gauge mediation in light of a 125$ GeV $ Higgs JHEP 07 (2013) 109 1303.0870
24 CMS Collaboration Search for supersymmetry in electroweak production with photons and large missing transverse energy in pp collisions at $ \sqrt{s} $ = 8 TeV PLB 759 (2016) 479 CMS-SUS-14-016
1602.08772
25 CMS Collaboration Data parking and data scouting at the CMS experiment CDS
26 CMS Collaboration The CMS experiment at the CERN LHC JINST 3 (2008) S08004 CMS-00-001
27 M. Cacciari, G. P. Salam, and G. Soyez The anti-$ k_t $ jet clustering algorithm JHEP 04 (2008) 063 0802.1189
28 CMS Collaboration Performance of photon reconstruction and identification with the CMS detector in proton-proton collisions at $ \sqrt{s} = $ 8 TeV JINST 10 (2015) P08010 CMS-EGM-14-001
1502.02702
29 CMS Collaboration Identification of b-quark jets with the CMS experiment JINST 8 (2013) P04013 CMS-BTV-12-001
1211.4462
30 CMS Collaboration Identification of b quark jets at the CMS Experiment in the LHC Run 2 CMS-PAS-BTV-15-001 CMS-PAS-BTV-15-001
31 C. J. Clopper and E. S. Pearson The use of confidence or fiducial limits illustrated in the case of the binomial Biometrika 26 (1934), no. 4, 404
32 CMS Collaboration Missing transverse energy performance of the CMS detector JINST 6 (2011) P09001 CMS-JME-10-009
1106.5048
33 CMS Collaboration Performance of the CMS missing transverse momentum reconstruction in pp data at $ \sqrt{s} $ = 8 TeV JINST 10 (2015), no. 02, P02006 CMS-JME-13-003
1411.0511
34 J. Alwall et al. The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations JHEP 07 (2014) 079 1405.0301
35 P. Nason A New method for combining NLO QCD with shower Monte Carlo algorithms JHEP 11 (2004) 040 hep-ph/0409146
36 S. Frixione, P. Nason, and C. Oleari Matching NLO QCD computations with Parton Shower simulations: the POWHEG method JHEP 11 (2007) 070 0709.2092
37 S. Alioli, P. Nason, C. Oleari, and E. Re A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX JHEP 06 (2010) 043 1002.2581
38 T. Melia, P. Nason, R. Rontsch, and G. Zanderighi W+W-, WZ and ZZ production in the POWHEG BOX JHEP 11 (2011) 078 1107.5051
39 P. Nason and G. Zanderighi $ W^+ W^- $ , $ W Z $ and $ Z Z $ production in the POWHEG-BOX-V2 EPJC 74 (2014), no. 1 1311.1365
40 T. Sj\"ostrand, S. Mrenna, and P. Skands PYTHIA 6.4 physics and manual JHEP 05 (2006) 026 hep-ph/0603175
41 T. Sjostrand, S. Mrenna, and P. Z. Skands A Brief Introduction to PYTHIA 8.1 CPC 178 (2008) 852--867 0710.3820
42 GEANT4 Collaboration GEANT4: A Simulation toolkit Nucl.Instrum.Meth. A 506 (2003) 250
43 G. Bozzi et al. Production of Drell-Yan lepton pairs in hadron collisions: Transverse-momentum resummation at next-to-next-to-leading logarithmic accuracy PLB 696 (2011) 207 1007.2351
44 T. Gehrmann et al. $ W^+W^- $ Production at Hadron Colliders in Next to Next to Leading Order QCD PRL 113 (2014), no. 21, 212001 1408.5243
45 C. Borschensky et al. Squark and gluino production cross sections in pp collisions at $ \sqrt{s} $ = 13, 14, 33 and 100 TeV EPJC 74 (2014), no. 12 1407.5066
46 B. Fuks, M. Klasen, D. R. Lamprea, and M. Rothering Gaugino production in proton-proton collisions at a center-of-mass energy of 8 TeV JHEP 10 (2012) 081 1207.2159
47 B. Fuks, M. Klasen, D. R. Lamprea, and M. Rothering Precision predictions for electroweak superpartner production at hadron colliders with Resummino EPJC 73 (2013) 2480 1304.0790
48 W. Beenakker et al. The Production of charginos / neutralinos and sleptons at hadron colliders PRL 83 (1999) 3780--3783, , [Erratum: PRLett.100,029901(2008)] hep-ph/9906298
49 CMS Collaboration Measurement of the inclusive top-quark pair + photon production cross section in the muon + jets channel in pp collisions at 8 TeV CDS
50 CMS Collaboration Measurement of the WW cross section pp collisions at sqrt(s)=13 TeV CMS-PAS-SMP-16-006 CMS-PAS-SMP-16-006
51 CMS Collaboration Measurement of the WZ production cross section in pp collisions at sqrt(s) = 13 TeV CMS-PAS-SMP-16-002 CMS-PAS-SMP-16-002
52 CMS Collaboration Measurement of the ZZ production cross section and $ \mathrm{Z} \to \ell\ell\ell'\ell' $ branching fraction in pp collisions at $ \sqrt{s}=13 \mathrm{TeV} $ CMS-PAS-SMP-16-001 CMS-PAS-SMP-16-001
53 T. Junk Confidence level computation for combining searches with small statistics Nucl.Instrum.Meth. A 434 (1999) 435 hep-ex/9902006
54 A. L. Read Presentation of search results: the CLs technique JPG 28 (2002) 2693
55 ATLAS Collaboration, CMS Collaboration, LHC Higgs Combination Group Collaboration Procedure for the LHC Higgs boson search combination in Summer 2011 CMS-NOTE-2011-005
56 E. Gross and O. Vitells Trial factors or the look elsewhere effect in high energy physics EPJC 70 (2010) 525 1005.1891
57 CMS Collaboration Search for supersymmetry in events with photons and missing transverse energy CMS-PAS-SUS-15-012 CMS-PAS-SUS-15-012
Compact Muon Solenoid
LHC, CERN