CMS-PAS-HIG-17-027

CMS-PAS-HIG-17-027
Search for heavy Higgs bosons decaying to a top quark pair in proton-proton collisions at $\sqrt{s} =$ 13 TeV
CMS Collaboration
March 2019

Abstract: Multiple new-physics models extending the standard model predict the existence of additional scalar (H) or pseudoscalar (A) Higgs bosons. In this note, a search is presented for such new bosons decaying to a top quark pair in proton-proton collisions at a center-of-mass energy of 13 TeV. The data set analyzed corresponds to an integrated luminosity of 35.9 fb $^{-1}$ collected by the CMS experiment at the LHC in 2016. Final states with one or two charged leptons are considered, where the lepton may be a muon or an electron. The invariant mass of the reconstructed top quark pair system and variables that are sensitive to the spin of the particles decaying into the top quark pair are used to search for signatures of the H or A bosons. The strength of the coupling of the hypothetical bosons to the top quark is probed as a function of the mass and width of the boson. The interference with the standard model top quark pair background is taken into account explicitly. The results are interpreted in a model-independent way as well as in a minimal supersymmetric standard model framework.
Links: CDS record (PDF) ; CADI line (restricted) ; These preliminary results are superseded in this paper, JHEP 04 (2020) 171. The superseded preliminary plots can be found here.

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: The production of new spin-0 states ${\mathrm{h}i}$ decaying into a top quark pair (leading order $s$ -channel Feynman diagram shown in the left) interferes with the SM production of top quark pairs (all gluon fusion diagrams, with the example $t$ channel shown in the right diagram).
png pdf	Figure 1-a: The production of new spin-0 states ${\mathrm{h}i}$ decaying into a top quark pair (leading order $s$ -channel Feynman diagram shown in the left) interferes with the SM production of top quark pairs (all gluon fusion diagrams, with the example $t$ channel shown in the right diagram).
png pdf	Figure 1-b: The production of new spin-0 states ${\mathrm{h}i}$ decaying into a top quark pair (leading order $s$ -channel Feynman diagram shown in the left) interferes with the SM production of top quark pairs (all gluon fusion diagrams, with the example $t$ channel shown in the right diagram).
png pdf	Figure 2: Observed and expected distributions of ${m_{{{\mathrm {t}\overline {\mathrm {t}}}}}}$ in different ${\| \cos {\theta ^*_{t_\ell}} \|}$ regions in the ${\mu} + \text {jets}$ (upper) and ${\mathrm {e}}+ \text {jets}$ (lower) channels. The expected distributions have been obtained with a background-only fit to the data, and an approximate post-fit uncertainty is shown with a gray band. The impact of an example signal is included in the lower panels for illustration.
png pdf	Figure 2-a: Observed and expected distributions of ${m_{{{\mathrm {t}\overline {\mathrm {t}}}}}}$ in different ${\| \cos {\theta ^*_{t_\ell}} \|}$ regions in the ${\mu} + \text {jets}$ (upper) and ${\mathrm {e}}+ \text {jets}$ (lower) channels. The expected distributions have been obtained with a background-only fit to the data, and an approximate post-fit uncertainty is shown with a gray band. The impact of an example signal is included in the lower panels for illustration.
png pdf	Figure 2-b: Observed and expected distributions of ${m_{{{\mathrm {t}\overline {\mathrm {t}}}}}}$ in different ${\| \cos {\theta ^*_{t_\ell}} \|}$ regions in the ${\mu} + \text {jets}$ (upper) and ${\mathrm {e}}+ \text {jets}$ (lower) channels. The expected distributions have been obtained with a background-only fit to the data, and an approximate post-fit uncertainty is shown with a gray band. The impact of an example signal is included in the lower panels for illustration.
png pdf	Figure 3: Observed and expected distributions of observables exploited in the dilepton channel. The expected distributions have been obtained with a background-only fit to the data, and an approximate post-fit uncertainty is shown with a gray band. The impact of an example signal is included in the lower panels for illustration.
png pdf	Figure 4: Model-independent constraints on the coupling strength modifier as a function of the heavy pseudoscalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {A}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 4-a: Model-independent constraints on the coupling strength modifier as a function of the heavy pseudoscalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {A}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 4-b: Model-independent constraints on the coupling strength modifier as a function of the heavy pseudoscalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {A}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 4-c: Model-independent constraints on the coupling strength modifier as a function of the heavy pseudoscalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {A}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 4-d: Model-independent constraints on the coupling strength modifier as a function of the heavy pseudoscalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {A}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 4-e: Model-independent constraints on the coupling strength modifier as a function of the heavy pseudoscalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {A}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 4-f: Model-independent constraints on the coupling strength modifier as a function of the heavy pseudoscalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {A}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 5: Model-independent constraints on the coupling strength modifier as a function of the heavy scalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {H}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 5-a: Model-independent constraints on the coupling strength modifier as a function of the heavy scalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {H}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 5-b: Model-independent constraints on the coupling strength modifier as a function of the heavy scalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {H}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 5-c: Model-independent constraints on the coupling strength modifier as a function of the heavy scalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {H}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 5-d: Model-independent constraints on the coupling strength modifier as a function of the heavy scalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {H}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 5-e: Model-independent constraints on the coupling strength modifier as a function of the heavy scalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {H}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 5-f: Model-independent constraints on the coupling strength modifier as a function of the heavy scalar boson mass, for relative widths of 0.5, 1, 2.5, 5, 10, and 25%. The observed constraints are indicated by the blue shaded area. The inner (green) band and the outer (yellow) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The unphysical region of phase space in which the partial width $\Gamma _{{\mathrm {H}} \to {{\mathrm {t}\overline {\mathrm {t}}}}}$ becomes larger than the total width is indicated by the hatched lines.
png pdf	Figure 6: Exclusion in the $(m_ {\mathrm {A}}, \tan\beta)$ plane of the hMSSM. The inner (dark gray) band and the outer (light gray) band indicate the regions containing 68 and 95%, respectively, of the distribution of constraints expected under the background-only hypothesis. The observed excluded region is indicated by the blue shaded area. Both H and A boson signals are included with masses and widths that correspond to a given point in the plane.

Tables
png pdf	Table 1: Event yields and composition of SM background in the single-muon and single-electron channels. Expected yields are computed after the background-only fit to the data as explained in the text. The benchmark signal represents a heavy pseudoscalar Higgs boson with a mass of 500 GeV, a relative total decay width of 5%, and $g_{{\mathrm{h}i} {{\mathrm {t}\overline {\mathrm {t}}}}} = 1$ , for the sum of the resonant part and the interference.
png pdf	Table 2: Event yields and composition of SM background in the dilepton channel. Expected yields are computed in the same way as in Table 1. The benchmark signal represents a heavy pseudoscalar Higgs boson with a mass of 500 GeV, a relative total decay width of 5%, and $g_{{\mathrm{h}i} {{\mathrm {t}\overline {\mathrm {t}}}}} = 1$ , for the sum of the resonant part and the interference.
png pdf	Table 3: The systematic uncertainties considered in the analysis, indicating the number of corresponding nuisance parameters (when more than one) in the statistical model, the type (affecting shape or only normalization), the affected processes, and the correlation among the lepton channels. Uncertainties tagged in the last column with "All'' are correlated among the single-lepton and dilepton channels. In case an uncertainty is only applicable to the single-muon, the single-electron, the single-lepton, or the dilepton channel, they are indicated with ${{\mu}}$ , ${\mathrm {e}}$ , $\ell$ , $\ell \ell$ , respectively.

Summary

Results are presented for the search for additional heavy Higgs bosons decaying to a pair of top quarks. A data sample recorded with the CMS detector at

$\sqrt{s} =$ 13 TeV is analyzed, corresponding to an integrated luminosity of 35.9 fb

$^{-1}$ . The final states with one or two leptons are utilized. The invariant mass of the reconstructed

$\mathrm{t\bar{t}}$ system as well as angular variables sensitive to the spin of the new boson are used to search for the signal, while taking into account the interference with the SM

$\mathrm{t\bar{t}}$ production. Constraints on the strength of the coupling of the sought-for boson to top quarks are reported, separately for the scalar and pseudoscalar cases, for the mass ranging from 400 to 750 GeV and the total relative width from 0.5 to 25%. These are the most stringent constraints on this coupling to date. The results are also interpreted in the hMSSM framework. This search probes the values of

$m_{\mathrm{A} }$ from 400 to 700 GeV and excludes the region with values of

$\tan\beta$ below 1.0 to 1.5, depending on

$m_{\mathrm{A} }$ . This extends the exclusion obtained in previous searches.

References
1	ATLAS Collaboration	Observation of a new particle in the search for the standard model Higgs boson with the ATLAS detector at the LHC	PLB 716 (2012) 1	1207.7214
2	CMS Collaboration	Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC	PLB 716 (2012) 30	CMS-HIG-12-028 1207.7235
3	J. Wess and B. Zumino	Supergauge transformations in four-dimensions	NPB 70 (1974) 39
4	S. Dimopoulos and H. Georgi	Softly broken supersymmetry and SU(5)	NPB 193 (1981) 150
5	G. C. Branco et al.	Theory and phenomenology of two-Higgs-doublet models	Phys. Rep. 516 (2012) 1
6	N. Craig, J. Galloway, and S. Thomas	Searching for signs of the second Higgs doublet		1305.2424
7	A. Djouadi et al.	The post-Higgs MSSM scenario: Habemus MSSM?	EPJC 73 (2013) 2650	1307.5205
8	K. Gaemers and F. Hoogeveen	Higgs production and decay into heavy flavours with the gluon fusion mechanism	PLB 146 (1984) 347
9	D. Dicus, A. Stange, and S. Willenbrock	Higgs decay to top quarks at hadron colliders	PLB 333 (1994) 126	9404359
10	W. Bernreuther, M. Flesch, and P. Haberl	Signatures of Higgs bosons in the top quark decay channel at hadron colliders	PRD 58 (1998) 114031	9709284
11	ATLAS Collaboration	Search for heavy Higgs bosons A/H decaying to a top quark pair in pp~collisions at $\sqrt{s} =$ 8 ~TeV with the ATLAS detector	PRL 119 (2017) 191803	1707.06025
12	CMS Collaboration	Search for physics beyond the standard model in events with two leptons of same sign, missing transverse momentum, and jets in proton-proton collisions at $\sqrt{s} =$ 13 TeV	EPJC 77 (2017) 578	CMS-SUS-16-035 1704.07323
13	ATLAS Collaboration	Search for heavy particles decaying into top-quark pairs using lepton-plus-jets events in proton--proton collisions at $\sqrt{s} =$ 13 ~TeV with the ATLAS detector	EPJC 78 (2018) 565	1804.10823
14	CMS Collaboration	Search for $\mathrm{t\bar{t}}$ resonances in highly boosted lepton+jets and fully hadronic final states in proton-proton collisions at $\sqrt{s} =$ 13 TeV	JHEP 07 (2017) 001	CMS-B2G-16-015 1704.03366
15	ATLAS Collaboration	Search for charged Higgs bosons decaying into top and bottom quarks at $\sqrt{s} =$ 13 TeV with the ATLAS detector	JHEP 11 (2018) 085	1808.03599
16	CMS Collaboration	Search for a charged Higgs boson in pp collisions at $\sqrt{s} =$ 8 TeV	JHEP 11 (2015) 018	CMS-HIG-14-023 1508.07774
17	CMS Collaboration	The CMS experiment at the CERN LHC	JINST 3 (2008) S08004	CMS-00-001
18	M. Cacciari, G. P. Salam, and G. Soyez	The anti- $k_t$ jet clustering algorithm	JHEP 04 (2008) 063	0802.1189
19	M. Cacciari, G. P. Salam, and G. Soyez	Fastjet user manual	EPJC 72 (2012) 1896	1111.6097
20	CMS Collaboration	Particle-flow reconstruction and global event description with the CMS detector	JINST 12 (2017) P10003	CMS-PRF-14-001 1706.04965
21	CMS Collaboration	Jet energy scale and resolution in the CMS experiment in pp~collisions at 8~TeV	JINST 12 (2017) P02014	CMS-JME-13-004 1607.03663
22	CMS Collaboration	Identification of heavy-flavour jets with the CMS detector in pp~collisions at 13~TeV	JINST 13 (2018) P05011	CMS-BTV-16-002 1712.07158
23	CMS Collaboration	Performance of electron reconstruction and selection with the CMS detector in proton-proton collisions at $\sqrt{s} =$ 8 ~ TeV	JINST 10 (2015) P06005	CMS-EGM-13-001 1502.02701
24	CMS Collaboration	Performance of CMS muon reconstruction in pp collision events at $\sqrt{s} =$ 7 ~ TeV	JINST 7 (2012) P10002	CMS-MUO-10-004 1206.4071
25	CMS Collaboration	Performance of missing transverse momentum reconstruction in proton-proton collisions at $\sqrt{s} =$ 13 TeV using the CMS detector	Submitted to JINST	CMS-JME-17-001 1903.06078
26	CMS Collaboration	CMS luminosity measurements for the 2016 data taking period	CMS-PAS-LUM-17-001	CMS-PAS-LUM-17-001
27	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
28	M. Spira, A. Djouadi, D. Graudenz, and P. M. Zerwas	Higgs boson production at the LHC	NPB 453 (1995) 17	hep-ph/9504378
29	NNPDF Collaboration	Parton distributions for the LHC Run II	JHEP 04 (2015) 040	1410.8849
30	T. Sjostrand, S. Mrenna, and P. Skands	PYTHIA 6.4 physics and manual	JHEP 05 (2006) 026	hep-ph/0603175
31	T. Sjostrand et al.	An introduction to PYTHIA 8.2	CPC 191 (2015) 159	1410.3012
32	P. Skands, S. Carrazza, and J. Rojo	Tuning PYTHIA 8.1: the Monash 2013 Tune	EPJC 74 (2014) 3024	1404.5630
33	CMS Collaboration	Event generator tunes obtained from underlying event and multiparton scattering measurements	EPJC 76 (2016) 155	CMS-GEN-14-001 1512.00815
34	B. Hespel, F. Maltoni, and E. Vryonidou	Signal background interference effects in heavy scalar production and decay to a top-anti-top pair	JHEP 10 (2016) 016	1606.04149
35	D. Eriksson, J. Rathsman, and O. Stal	2HDMC: Two-Higgs-Doublet Model calculator physics and manual	CPC 181 (2010) 189	0902.0851
36	R. V. Harlander, S. Liebler, and H. Mantler	SusHi: A program for the calculation of Higgs production in gluon fusion and bottom-quark annihilation in the standard model and the MSSM	CPC 184 (2013) 1605	1212.3249
37	P. Nason	A new method for combining NLO QCD with shower Monte Carlo algorithms	JHEP 11 (2004) 040	hep-ph/0409146
38	S. Frixione, P. Nason, and C. Oleari	Matching NLO QCD computations with parton shower simulations: the POWHEG method	JHEP 11 (2007) 070	0709.2092
39	S. Alioli et al.	A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX	JHEP 06 (2010) 043	1002.2581
40	J. M. Campbell, R. K. Ellis, P. Nason, and E. Re	Top-pair production and decay at NLO matched with parton showers	JHEP 04 (2015) 114	1412.1828
41	CMS Collaboration	Investigations of the impact of the parton shower tuning in Pythia 8 in the modelling of $\mathrm{t\overline{t}}$ at $\sqrt{s}=$ 8 and 13 TeV	CMS-PAS-TOP-16-021	CMS-PAS-TOP-16-021
42	M. Czakon and A. Mitov	Top++: a program for the calculation of the top-pair cross-section at hadron colliders	CPC 185 (2014) 2930	1112.5675
43	M. Botje et al.	The PDF4LHC working group interim recommendations		1101.0538
44	A. Martin et al.	Uncertainties on $\alpha_s$ in global PDF analyses and implications for predicted hadronic cross sections	EPJC 64 (2009) 653	0905.3531
45	J. Gao et al.	The CT10 NNLO global analysis of QCD	PRD 89 (2014) 033009	1302.6246
46	R. D. Ball et al.	Parton distributions with LHC data	NPB 867 (2013) 244	1207.1303
47	CMS Collaboration	Measurement of differential cross sections for top quark pair production using the lepton+jets final state in proton-proton collisions at 13 TeV	PRD 95 (2017) 092001	CMS-TOP-16-008 1610.04191
48	CMS Collaboration	Measurement of normalized differential $\mathrm{t}\bar{\mathrm{t}}$ ~cross sections in the dilepton channel from pp~collisions at $\sqrt{s} =$ 13 ~TeV	JHEP 04 (2018) 060	CMS-TOP-16-007 1708.07638
49	M. Aliev et al.	-- HATHOR -- HAdronic Top and Heavy quarks crOss section calculatoR	CPC 182 (2011) 1034	1007.1327
50	P. Kant et al.	HATHOR for single top-quark production: Updated predictions and uncertainty estimates for single top-quark production in hadronic collisions	CPC 191 (2015) 74	1406.4403
51	N. Kidonakis	Top Quark Production	in Proceedings, Helmholtz International Summer School on Physics of Heavy Quarks and Hadrons (HQ 2013), p. 139 2014	1311.0283
52	J. Alwall et al.	Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions	EPJC 53 (2008) 473	0706.2569
53	K. Melnikov and F. Petriello	Electroweak gauge boson production at hadron colliders through O( $\alpha_s^2$ )	PRD 74 (2006) 114017	0609070
54	Y. Li and F. Petriello	Combining QCD and electroweak corrections to dilepton production in FEWZ	PRD 86 (2012) 094034	1208.5967
55	S. Frixione and B. R. Webber	Matching NLO QCD computations and parton shower simulations	JHEP 06 (2002) 029	hep-ph/0204244
56	T. Gehrmann et al.	$\mathrm{W}^+\mathrm{W}^-$ production at hadron colliders in NNLO QCD	PRL 113 (2014) 212001	1408.5243
57	J. M. Campbell and R. K. Ellis	MCFM for the Tevatron and the LHC	NPPS 205-206 (2010) 10	1007.3492
58	GEANT4 Collaboration	Geant4 -- a simulation toolkit	NIMA 506 (2003) 250
59	B. A. Betchart, R. Demina, and A. Harel	Analytic solutions for neutrino momenta in decay of top quarks	NIMA 736 (2014) 169	1305.1878
60	A. Loginov	Strategies of data-driven estimations of $\mathrm{t}\bar{\mathrm{t}}$ ~backgrounds in ATLAS	Nuovo Cim. C 033 (2010) 175
61	CMS Collaboration	Measurements of $\mathrm{t\overline{t}}$ differential cross sections in proton-proton collisions at $\sqrt{s}=$ 13 TeV using events containing two leptons	JHEP 02 (2019) 149	CMS-TOP-17-014 1811.06625
62	CMS Collaboration	Measurement of the $t\bar{t}$ production cross section and the top quark mass in the dilepton channel in $pp$ collisions at $\sqrt{s}=$ 7 TeV	JHEP 07 (2011) 049	CMS-TOP-11-002 1105.5661
63	CMS Collaboration	Measurement of the differential cross section for top quark pair production in pp collisions at $\sqrt{s} =$ 8 TeV	EPJC 75 (2015) 542	CMS-TOP-12-028 1505.04480
64	W. Bernreuther, A. Brandenburg, Z. G. Si, and P. Uwer	Top quark pair production and decay at hadron colliders	NPB 690 (2004) 81	0403035
65	CMS Collaboration	Measurement of the top quark mass using proton-proton data at $\sqrt{s} =$ 7 and 8 TeV	PRD 93 (2016) 072004	CMS-TOP-14-022 1509.04044
66	R. Barlow and C. Beeston	Fitting using finite Monte Carlo samples	CPC 77 (1993) 219
67	W. S. Cleveland	Robust locally weighted regression and smoothing scatterplots	J. Am. Stat. Assoc. 74 (1979) 829
68	W. S. Cleveland and S. J. Devlin	Locally-weighted regression: An approach to regression analysis by local fitting	J. Am. Stat. Assoc. 83 (1988) 596
69	G. Cowan, K. Cranmer, E. Gross, and O. Vitells	Asymptotic formulae for likelihood-based tests of new physics	EPJC 71 (2011) 1554	1007.1727
70	T. Junk	Confidence level computation for combining searches with small statistics	NIMA 434 (1999) 435	hep-ex/9902006
71	A. L. Read	Presentation of search results: the $CL_s$ technique	JPG 28 (2002) 2693
72	M. Baak, S. Gadatsch, R. Harrington, and W. Verkerke	Interpolation between multi-dimensional histograms using a new non-linear moment morphing method	NIMA 771 (2015) 39	1410.7388
73	L. Demortier	P values and nuisance parameters	in Statistical issues for LHC physics. Proceedings, Workshop, PHYSTAT-LHC, Geneva, Switzerland, June 27-29, 2007, p. 23 2008
74	J. H. Kuhn, A. Scharf, and P. Uwer	Weak interactions in top-quark pair production at hadron colliders: An update	PRD 91 (2015), no. 1, 014020	1305.5773