CMS-PAS-SUS-16-023

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
CMS Collaboration
August 2016

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.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ;

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	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}} $.
png pdf	Figure 2: Feynman diagram corresponding to the TChiWg simplified model.
png pdf	Figure 3-a: Feynman diagrams of the T5gg (a) and T5Wg (b) simplified models.
png pdf	Figure 3-b: Feynman diagrams of the T5gg (a) and T5Wg (b) simplified models.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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.
png pdf	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
png pdf	Table 1: Systematic uncertainties of the separate backgrounds. The uncertainties are relative to the respective backgrounds.
png pdf	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.
png pdf	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