CMS-HIG-20-004

CMS-HIG-20-004 ; CERN-EP-2022-114
Search for nonresonant Higgs boson pair production in the four leptons plus two b jets final state in proton-proton collisions at $\sqrt{s} = $ 13 TeV
CMS Collaboration
22 June 2022
JHEP 06 (2023) 130
Abstract: The first search for nonresonant production of Higgs boson pairs (HH) with one H decaying into four leptons and the other into a pair of b quarks is presented, using proton-proton collisions recorded at a center-of-mass energy of $\sqrt{s} = $ 13 TeV by the CMS experiment. The analyzed data correspond to an integrated luminosity of 138 fb$^{-1}$. A 95% confidence level upper limit of 32.4 is set on the signal strength modifier $\mu$, defined as the ratio of the observed HH production rate in the ${\mathrm{H}\mathrm{H}} \to\mathrm{Z}\mathrm{Z}^{*}\mathrm{b}\mathrm{\bar{b}}\to 4\ell\mathrm{b}\mathrm{\bar{b}}$ decay channel to the standard model expectation. Possible modifications of the H trilinear coupling $\lambda_\text{HHH}$ with respect to the standard model (SM) value are investigated. The coupling modifier $\kappa_{\lambda}$, defined as $\lambda_\text{HHH}$ divided by its SM prediction, is constrained to be within the observed (expected) range $-$8.8 ($-$9.8) $ < \kappa_{\lambda} < $ 13.4 (15.0) at 95% confidence level.
Links: e-print arXiv:2206.10657 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ;

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: Feynman diagrams contributing to Higgs boson pair production via gluon-gluon fusion in the SM at LO.
png pdf	Figure 2: The $m(4\ell)$ (left) and $m(\mathrm{b} \mathrm{\bar{b}})$ (right) distributions. The $m(\mathrm{b} \mathrm{\bar{b}})$ plot is drawn after the selection: 115 $ < m(4\ell) < $ 135 GeV. In the ratio plot, the grey dashed shades represent the relative statistical uncertainty on the total estimated background.
png pdf	Figure 2-a: The $m(4\ell)$ (left) and $m(\mathrm{b} \mathrm{\bar{b}})$ (right) distributions. The $m(\mathrm{b} \mathrm{\bar{b}})$ plot is drawn after the selection: 115 $ < m(4\ell) < $ 135 GeV. In the ratio plot, the grey dashed shades represent the relative statistical uncertainty on the total estimated background.
png pdf	Figure 2-b: The $m(4\ell)$ (left) and $m(\mathrm{b} \mathrm{\bar{b}})$ (right) distributions. The $m(\mathrm{b} \mathrm{\bar{b}})$ plot is drawn after the selection: 115 $ < m(4\ell) < $ 135 GeV. In the ratio plot, the grey dashed shades represent the relative statistical uncertainty on the total estimated background.
png pdf	Figure 3: Inclusive BDT distributions for simulated signal, estimated background components, and data for the combination of the three different final states (4$\mu $, 4e, and 2e2$\mu $) and data-taking years. In the ratio plot, the grey dashed shades represent the relative statistical uncertainty on the total estimated background.
png pdf	Figure 4: Left: upper limit on the signal strength at 95% CL for each year and for their combination. Right: expected and observed 95% CL upper limits on the SM-like HH production cross section obtained for different values of $\kappa _\lambda $. The green and yellow bands represent, respectively, the one and two standard deviation (s.d.) quantiles around the expected limit. The red curve is the HH theoretical prediction cross section as a function of $\kappa _\lambda $.
png pdf	Figure 4-a: Left: upper limit on the signal strength at 95% CL for each year and for their combination. Right: expected and observed 95% CL upper limits on the SM-like HH production cross section obtained for different values of $\kappa _\lambda $. The green and yellow bands represent, respectively, the one and two standard deviation (s.d.) quantiles around the expected limit. The red curve is the HH theoretical prediction cross section as a function of $\kappa _\lambda $.
png pdf	Figure 4-b: Left: upper limit on the signal strength at 95% CL for each year and for their combination. Right: expected and observed 95% CL upper limits on the SM-like HH production cross section obtained for different values of $\kappa _\lambda $. The green and yellow bands represent, respectively, the one and two standard deviation (s.d.) quantiles around the expected limit. The red curve is the HH theoretical prediction cross section as a function of $\kappa _\lambda $.

Tables
png pdf	Table 1: Expected yields in the 4$\ell $ SR after additionally requiring at least two jets in the event. "Others'' represents contributions from $\mathrm{t} \mathrm{\bar{t}} $W, WWZ, WZZ, and ZZZ processes.
png pdf	Table 2: Summary of experimental systematic uncertainties. The effect of b-tagging SF, JER, and JES is propagated to the shape of the BDT distribution.
png pdf	Table 3: Summary of the theory systematic uncertainties considered in this analysis.

Summary

The first search for nonresonant Higgs boson (H) pair production in the four lepton $\mathrm{b}\mathrm{\bar{b}}$ final state is presented. This search uses a data sample collected in proton-proton collisions at $\sqrt{s} = =$ 13 TeV by the CMS detector during the years 2016-2018 corresponding to an integrated luminosity of 138 fb$^{-1}$. The results are found to be compatible with the standard model (SM) expectations. An observed (expected) upper limit on the HH production cross section is set at 32.4 (39.6) times the SM expected rate at the 95% confidence level. Possible modifications of the H trilinear coupling $\lambda_\text{HHH}$ with respect to the standard model (SM) value are investigated. The coupling modifier $\kappa_{\lambda}$, defined as $\lambda_\text{HHH}$ divided by its SM prediction, is constrained to be within the observed (expected) range $-$8.8 ($-$9.8) $ < \kappa_{\lambda} < $ 13.4 (15.0) at 95% confidence level.

The limits set by this analysis are complementary with those obtained by more sensitive channels, despite the lower branching fraction of the $4\ell\mathrm{b}\mathrm{\bar{b}}$ final state.

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 with mass near 125 GeV in pp collisions at $ \sqrt{s} = $ 7 and 8 TeV	JHEP 06 (2013) 081	CMS-HIG-12-036 1303.4571
3	ATLAS and CMS Collaborations	Combined measurement of the Higgs boson mass in pp collisions at $ \sqrt{s}= $ 7 and 8 TeV with the ATLAS and CMS experiments	PRL 114 (2015) 191803	1503.07589
4	CMS Collaboration	Measurements of properties of the Higgs boson decaying into the four-lepton final state in pp collisions at $ \sqrt{s}= $ 13 TeV	JHEP 11 (2017) 047	CMS-HIG-16-041 1706.09936
5	CMS Collaboration	Combined measurements of Higgs boson couplings in proton-proton collisions at $ \sqrt{s}=$ 13 TeV	EPJC 79 (2019) 421	CMS-HIG-17-031 1809.10733
6	J. Baglio et al.	The measurement of the Higgs self-coupling at the LHC: theoretical status	JHEP 04 (2013) 151	1212.5581
7	ATLAS Collaboration	Search for Higgs boson pair production in the $ \gamma\gamma \mathrm{b}\overline{\mathrm{b}} $ final state using pp collision data at $ \sqrt{s}= $ 8 TeV from the ATLAS detector	PRL 114 (2015) 081802	1406.5053
8	ATLAS Collaboration	Search for Higgs boson pair production in the $ \mathrm{b}\overline{\mathrm{b}}\mathrm{b}\overline{\mathrm{b}} $ final state from pp collisions at $ \sqrt{s} = $ 8 TeV with the ATLAS detector	EPJC 75 (2015) 412	1506.00285
9	ATLAS Collaboration	Searches for Higgs boson pair production in the $ \mathrm{H}\mathrm{H}\to\mathrm{b}\mathrm{b}\tau\tau$, $\gamma\gamma \mathrm{W}\mathrm{W}^*$, $\gamma\gamma \mathrm{b}\mathrm{b}$, $\mathrm{b}\mathrm{b}\mathrm{b}\mathrm{b} $ channels with the ATLAS detector	PRD 92 (2015) 092004	1509.04670
10	ATLAS Collaboration	Search for pair production of Higgs bosons in the $ \mathrm{b}\overline{\mathrm{b}}\mathrm{b}\overline{\mathrm{b}} $ final state using proton-proton collisions at $ \sqrt{s} = $ 13 TeV with the ATLAS detector	PRD 94 (2016) 052002	1606.04782
11	CMS Collaboration	Search for two Higgs bosons in final states containing two photons and two bottom quarks in proton-proton collisions at 8 TeV	PRD 94 (2016) 052012	CMS-HIG-13-032 1603.06896
12	CMS Collaboration	Search for resonant pair production of Higgs bosons decaying to two bottom quark-antiquark pairs in proton-proton collisions at 8 TeV	PLB 749 (2015) 560	CMS-HIG-14-013 1503.04114
13	CMS Collaboration	Search for a massive resonance decaying to a pair of Higgs bosons in the four b quark final state in proton-proton collisions at $ \sqrt{s}= $ 13 TeV	PLB 781 (2018) 244	1710.04960
14	CMS Collaboration	Search for higgs boson pair production in the $ \mathrm{b}\overline{\mathrm{b}}\tau\tau $ final state in proton-proton collisions at $ \sqrt{s}= $ 8 TeV	PRD 96 (2017) 072004	CMS-HIG-15-013 1707.00350
15	CMS Collaboration	Search for Higgs boson pair production in events with two bottom quarks and two tau leptons in proton-proton collisions at $ \sqrt s = $ 13 TeV	PLB 778 (2018) 101	CMS-HIG-17-002 1707.02909
16	CMS Collaboration	Search for resonant and nonresonant Higgs boson pair production in the $ \mathrm{b}\overline{\mathrm{b}}\ell\nu\ell\nu $ final state in proton-proton collisions at $ \sqrt{s}= $ 13 TeV	JHEP 01 (2018) 054	CMS-HIG-17-006 1708.04188
17	CMS Collaboration	Combined Higgs boson production and decay measurements with up to 137 fb$^{-1}$ of proton-proton collision data at $ \sqrt{s} = $ 13 TeV	CMS Physics Analysis Summary, 2020 CMS-PAS-HIG-19-005	CMS-PAS-HIG-19-005
18	ATLAS Collaboration	Combination of searches for Higgs boson pairs in pp collisions at $ \sqrt{s} = $ 13 TeV with the ATLAS detector	PLB 800 (2020) 135103	1906.02025
19	CMS Collaboration	Combination of searches for Higgs boson pair production in proton-proton collisions at $ \sqrt{s} = $ 13 TeV	PRL 122 (2019) 121803	CMS-HIG-17-030 1811.09689
20	J. Baglio et al.	$ \mathrm{g}\mathrm{g} \to \mathrm{H}\mathrm{H} $: Combined uncertainties	PRD 103 (2021) 056002	2008.11626
21	G. Heinrich et al.	NLO predictions for Higgs boson pair production with full top quark mass dependence matched to parton showers	JHEP 08 (2017) 088	1703.09252
22	G. Buchalla et al.	Higgs boson pair production in non-linear Effective Field Theory with full $ m_\text{t} $-dependence at NLO QCD	JHEP 09 (2018) 057	1806.05162
23	F. Goertz, A. Papaefstathiou, L. L. Yang, and J. Zurita	Higgs boson pair production in the D=6 extension of the SM	JHEP 04 (2015) 167	1410.3471
24	CMS Collaboration	The CMS experiment at the CERN LHC	JINST 3 (2008) S08004
25	CMS Collaboration	Measurements of production cross sections of the Higgs boson in the four-lepton final state in proton-proton collisions at $ \sqrt{s} = $ 13 TeV	EPJC 81 (2021) 488	CMS-HIG-19-001 2103.04956
26	S. Alioli, P. Nason, C. Oleari, and E. Re	NLO vector-boson production matched with shower in POWHEG	JHEP 07 (2008) 060	0805.4802
27	P. Nason	A new method for combining NLO QCD with shower Monte Carlo algorithms	JHEP 11 (2004) 040	hep-ph/0409146
28	S. Frixione, P. Nason, and C. Oleari	Matching NLO QCD computations with parton shower simulations: the POWHEG method	JHEP 11 (2007) 070	0709.2092
29	P. Nason and C. Oleari	NLO Higgs boson production via vector-boson fusion matched with shower in POWHEG	JHEP 02 (2010) 037	0911.5299
30	H. B. Hartanto, B. Jager, L. Reina, and D. Wackeroth	Higgs boson production in association with top quarks in the POWHEG BOX	PRD 91 (2015) 094003	1501.04498
31	J. M. Campbell et al.	NLO Higgs boson production plus one and two jets using the POWHEG BOX, MadGraph4 and MCFM	JHEP 07 (2012) 092	1202.5475
32	G. Luisoni, P. Nason, C. Oleari, and F. Tramontano	$ \mathrm{H}\mathrm{W}^{\pm}/\mathrm{H}\mathrm{Z} $ + 0 and 1 jet at NLO with the POWHEG BOX interfaced to GoSam and their merging within MiNLO	JHEP 10 (2013) 083	1306.2542
33	Y. Gao et al.	Spin determination of single-produced resonances at hadron colliders	PRD 81 (2010) 075022	1001.3396
34	R. Frederix and S. Frixione	Merging meets matching in MC@NLO	JHEP 12 (2012) 061	1209.6215
35	M. Grazzini, S. Kallweit, and D. Rathlev	ZZ production at the LHC: fiducial cross sections and distributions in NNLO QCD	PL 750 (2015) 407	1507.06257
36	J. M. Campbell and R. K. Ellis	MCFM for the Tevatron and the LHC	Nucl. Phys. Proc. Suppl. 205 (2010) 10	1007.3492
37	J. M. Campbell, R. K. Ellis, and C. Williams	Bounding the Higgs width at the LHC using full analytic results for $ gg \to \mathrm{e}^- \mathrm{e}^+ \mu^- \mu^+ $	JHEP 04 (2014) 060	1311.3589
38	M. Bonvini et al.	Signal-background interference effects in $ gg \to \mathrm{H} \to \mathrm{W}\mathrm{W} $ beyond leading order	PRD 88 (2013) 034032	1304.3053
39	S. Catani and M. Grazzini	An NNLO subtraction formalism in hadron collisions and its application to Higgs boson production at the LHC	PRL 98 (2007) 222002	hep-ph/0703012
40	M. Grazzini	NNLO predictions for the Higgs boson signal in the $ \mathrm{H} \rightarrow \mathrm{W}\mathrm{W} \rightarrow \ell \nu \ell \nu $ and $ \mathrm{H} \rightarrow \mathrm{Z}\mathrm{Z} \rightarrow 4\ell $ decay channels	JHEP 02 (2008) 043	0801.3232
41	M. Grazzini and H. Sargsyan	Heavy-quark mass effects in Higgs boson production at the LHC	JHEP 09 (2013) 129	1306.4581
42	T. Sjöstrand et al.	An introduction to PYTHIA 8.2	Comput. Phys. Commun. 191 (2015) 159	1410.3012
43	CMS Collaboration	Event generator tunes obtained from underlying event and multiparton scattering measurements	EPJC 76 (2016) 155	CMS-GEN-14-001 1512.00815
44	CMS Collaboration	Extraction and validation of a new set of CMS PYTHIA8 tunes from underlying-event measurements	EPJC 80 (2020) 4	CMS-GEN-17-001 1903.12179
45	NNPDF Collaboration	Parton distributions for the LHC run II	JHEP 04 (2015) 040	1410.8849
46	GEANT4 Collaboration	GEANT4---a simulation toolkit	NIM A 506 (2003) 250
47	J. Allison et al.	GEANT4 developments and applications	IEEE Trans. Nucl. Sci. 53 (2006) 270
48	CMS Collaboration	Particle-flow reconstruction and global event description with the CMS detector	JINST 12 (2017) P10003	CMS-PRF-14-001 1706.04965
49	CMS Collaboration	Technical proposal for the Phase-II upgrade of the Compact Muon Solenoid	CMS Technical Proposal CERN-LHCC-2015-010, CMS-TDR-15-02, 2015 CDS
50	CMS Collaboration	Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC	JINST 16 (2021) P05014	CMS-EGM-17-001 2012.06888
51	CMS Collaboration	Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at $ \sqrt{s}= $ 13 TeV	JINST 13 (2018) P06015	CMS-MUO-16-001 1804.04528
52	CMS Collaboration	Pileup mitigation at CMS in 13 TeV data	JINST 15 (2020) P09018	CMS-JME-18-001 2003.00503
53	CMS Collaboration	Measurement of the inclusive W and Z production cross sections in pp collisions at $ \sqrt{s}= $ 7 TeV with the CMS experiment	JHEP 10 (2011) 132	CMS-EWK-10-005 1107.4789
54	M. Cacciari, G. P. Salam, and G. Soyez	The anti-$ k_\mathrm{T} $ jet clustering algorithm	JHEP 04 (2008) 063	0802.1189
55	M. Cacciari, G. P. Salam, and G. Soyez	FastJet user manual	EPJC 72 (2012) 1896	1111.6097
56	CMS Collaboration	Jet algorithms performance in 13 TeV data	CMS Physics Analysis Summary, 2017 CMS-PAS-JME-16-003	CMS-PAS-JME-16-003
57	CMS Collaboration	Determination of jet energy calibration and transverse momentum resolution in CMS	JINST 6 (2011) P11002	CMS-JME-10-011 1107.4277
58	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
59	CMS Collaboration	Jet energy scale and resolution performance with 13 TeV data collected by CMS in 2016-2018	Detectors and Experimental Techniques CERN-CMS-DP-2020-019, 2020 CDS
60	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
61	H. Voss, A. Höcker, J. Stelzer, and F. Tegenfeldt	TMVA, the toolkit for multivariate data analysis with ROOT	in XIth International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT) [PoS(ACAT)040], 2007 link	physics/0703039
62	M. Baak, S. Gadatsch, R. Harrington, and W. Verkerke	Interpolation between multi-dimensional histograms using a new non-linear moment morphing method	NIM A 771 (2015) 39	1410.7388
63	CMS Collaboration	Precision luminosity measurement in proton-proton collisions at $ {\sqrt{s}= $ 13 TeV in 2015 and 2016 at CMS	EPJC 81 (2021) 800	CMS-LUM-17-003 2104.01927
64	CMS Collaboration	CMS luminosity measurement for the 2017 data-taking period at $ \sqrt{s}= $ 13 TeV	CMS Physics Analysis Summary, 2018 CMS-PAS-LUM-17-004	CMS-PAS-LUM-17-004
65	CMS Collaboration	CMS luminosity measurement for the 2018 data-taking period at $ \sqrt{s}= $ 13 TeV	CMS Physics Analysis Summary, 2019 CMS-PAS-LUM-18-002	CMS-PAS-LUM-18-002
66	CMSnoop	Report from Working Group 2: Higgs Physics at the HL-LHC and HE-LHC	\hrefM.~Cepeda et~al.,, 2019 link	1902.00134
67	A. L. Read	Presentation of search results: the CL$ _\mathrm{s} $ technique	in Durham IPPP Workshop: Advanced Statistical Techniques in Particle Physics, . Durham, UK, March, . [], 2002 JPG 28 (2002) 2693
68	T. Junk	Confidence level computation for combining searches with small statistics	NIM A 434 (1999) 435	hep-ex/9902006
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	ATLAS and CMS Collaborations	Procedure for the LHC Higgs boson search combination in summer 2011	Technical Report CMS-NOTE-2011-005, ATL-PHYS-PUB-2011-11, 2011 link
71	A. Carvalho et al.	Higgs pair production: choosing benchmarks with cluster analysis	JHEP 04 (2016) 126	1507.02245
72	CMS Collaboration	HepData record for this analysis	link