CMS-PAS-SUS-23-008

CMS-PAS-SUS-23-008
Search for dark matter produced in association with a pair of bottom quarks in proton-proton collisions at $ \sqrt{s}= $ 13 TeV
CMS Collaboration
2 April 2024

Abstract: A search for dark matter (DM) particles produced in association with bottom quarks is presented. The analysis uses proton-proton collision data at a center-of-mass energy of $ \sqrt{s}= $ 13 TeV, corresponding to an integrated luminosity of 138 fb$ ^{-1} $. The search is performed in the final state with large missing transverse momentum and a pair of jets originated from bottom quarks. No significant excess of data is observed with respect to the standard model expectation. Limits are set on the DM production cross section in the context of two Higgs doublet models with an additional light pseudoscalar (2HDM+a). This is the first search at the LHC to probe DM produced in association with two nonresonant b quarks in 2HDM+a. Sensitivity to the parameter space with tan$ \beta \leq $ 15 is achieved, capitalizing on the enhancement of couplings between pseudoscalars and bottom quarks with $ \tan \beta $.
Links: CDS record (PDF) ; CADI line (restricted) ; These preliminary results are superseded in this paper, Submitted to JHEP. The superseded preliminary plots can be found here.

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: Feynman diagram for the $ \mathrm{b}\overline{\mathrm{b}}+p_{\mathrm{T}}^\text{miss} $ process in the 2HDM+a model.
png pdf	Figure 2: Distributions of the generator-level $ p_{\mathrm{T}}^\text{miss} $ for different illustrative lighter pseudoscalar masses $ m_{\textrm{a}} $.
png pdf	Figure 3: QCD background contribution in the QCD CRs (black and pink dots) in the 2b category in 2017. The exponential is fitted in the range $ \textrm{min}(\Delta\phi(\textrm{jet, }{\vec p}_{\mathrm{T}}^{\,\text{miss}})) < $ 0.3, checked to perform well in the range 0.3 $ < \textrm{min}(\Delta\phi(\textrm{jet, }{\vec p}_{\mathrm{T}}^{\,\text{miss}})) < $ 0.5, and extrapolated to the SRs for $ \textrm{min}(\Delta\phi(\textrm{jet, }{\vec p}_{\mathrm{T}}^{\,\text{miss}})) > $ 0.5.
png pdf	Figure 4: Observed and predicted $ p_{\mathrm{T}}^\text{miss} $ or recoil distributions in the 1b category, in the SR and CRs. The uncertainty band includes all sources of uncertainty, both systematic and statistical.
png pdf	Figure 5: Observed and predicted $ \cos\Theta^{*} $ distributions in the 2b category, in the SR and CRs. The uncertainty band includes all sources of uncertainty, both systematic and statistical.
png pdf	Figure 6: 95% CL upper limit on the signal strength modifyer of DM produced in association with a pair of b quarks for $ m_{\textrm{A}}= $ 600 GeV, $ \sin\theta= $ 0.7, $ m_{\chi}= $ 1 GeV, and $ \tan\beta= $ 35, for the combination of SR1 and SR2. The green and yellow bands show the $ \pm $ 1 and $ \pm $ 2 standard deviations from expected limits
png pdf	Figure 7: Left: 95% CL Upper limit on the signal strength in the $ m_{\textrm{a}}-\tan\beta $ plane. The shaded area above the curve is excluded. Right: Upper limit on the signal strength in the $ m_{\textrm{a}}-\sin\theta $ plane. The shaded area above the curve is excluded.
png pdf	Figure 7-a: Left: 95% CL Upper limit on the signal strength in the $ m_{\textrm{a}}-\tan\beta $ plane. The shaded area above the curve is excluded. Right: Upper limit on the signal strength in the $ m_{\textrm{a}}-\sin\theta $ plane. The shaded area above the curve is excluded.
png pdf	Figure 7-b: Left: 95% CL Upper limit on the signal strength in the $ m_{\textrm{a}}-\tan\beta $ plane. The shaded area above the curve is excluded. Right: Upper limit on the signal strength in the $ m_{\textrm{a}}-\sin\theta $ plane. The shaded area above the curve is excluded.

Tables
png pdf	Table 1: Preselection criteria applied to all the events entering the SRs and CRs.

Summary

A search for dark matter produced in association with a pair of bottom quarks is performed using data collected by the CMS detector in Run 2 and corresponding to an integrated luminosity of 138 fb$ ^{-1} $. The analysis aims to capture the signal using two independent categories with different multiplicities of jets reconstructed as originating from a b quark. The results are interpreted in the framework of a simplified model, namely 2HDM+a. This search performs best in the high $ \tan\beta $ phase space, where the signal production cross section is enhanced. This provides a complementary search to constrain the 2HDM+a model parameter phase space in the region where other DM searches are less sensitive. The observed exclusion range on the DM particle mass is up to 260 GeV for $ \tan\beta= $ 35, $ \sin\theta= $ 0.7, and $ m_{\textrm{A}}= $ 600 GeV.

References
1	N. Deruelle and J.-P. Uzan	The Lambda-CDM model of the hot Big Bang	OUP Academic, 2018 link
2	Planck Collaboration	Planck 2018 results. I. Overview and the cosmological legacy of Planck	Astron. Astrophys. 641 (2020) A1	1807.06205
3	K. Freese	Status of Dark Matter in the Universe	Int. J. Mod. Phys. 1 (2017) 325	1701.01840
4	J. L. Feng	Dark Matter Candidates from Particle Physics and Methods of Detection	Ann. Rev. Astron. Astrophys. 48 (2010) 495	1003.0904
5	V. Trimble	Existence and nature of dark matter in the universe	Annual Review of Astronomy and Astrophysics 25 (1987) 425
6	G. Jungman, M. Kamionkowski, and K. Griest	Supersymmetric dark matter	Phys. Rept. 267 (1996) 195	hep-ph/9506380
7	CMS Collaboration	Search for dark matter produced in association with a single top quark or a top quark pair in proton-proton collisions at $ \sqrt{s}= $ 13 TeV	JHEP 03 (2019) 141	CMS-EXO-18-010 1901.01553
8	CMS Collaboration	Search for dark matter particles produced in association with a top quark pair at $ \sqrt{s} = $ 13 TeV	PRL 122 (2019) 011803	CMS-EXO-16-049 1807.06522
9	ATLAS Collaboration	Search for dark matter produced in association with bottom or top quarks in $ \sqrt{s}= $ 13 TeV pp collisions with the ATLAS detector	EPJC 78 (2018) 18	1710.11412
10	CMS Collaboration	Searches for physics beyond the standard model with the $ M_\mathrm{T2} $ variable in hadronic final states with and without disappearing tracks in proton-proton collisions at $ \sqrt{s}= $ 13 TeV	EPJC 80 (2020) 3	CMS-SUS-19-005 1909.03460
11	D. Abercrombie et al.	Dark Matter benchmark models for early LHC Run-2 Searches: Report of the ATLAS/CMS Dark Matter Forum	Phys. Dark Univ. 27 (2020) 100371	1507.00966
12	M. Bauer, U. Haisch, and F. Kahlhoefer	Simplified dark matter models with two Higgs doublets: I. Pseudoscalar mediators	JHEP 05 (2017) 138	1701.07427
13	ATLAS Collaboration	Search for heavy ZZ resonances in the $ \ell ^+\ell ^-\ell ^+\ell ^- $ and $ \ell ^+\ell ^-\nu \bar{\nu } $ final states using proton-proton collisions at $ \sqrt{s}= $ 13 $ \text {TeV} $ with the ATLAS detector	EPJC 78 (2018) 293	1712.06386
14	ATLAS Collaboration	Search for heavy resonances decaying into $ WW $ in the $ e\nu\mu\nu $ final state in $ pp $ collisions at $ \sqrt{s}= $ 13 TeV with the ATLAS detector	EPJC 78 (2018) 24	1710.01123
15	CMS Collaboration	Search for beyond the standard model Higgs bosons decaying into a $ \mathrm{b\overline{b}} $ pair in pp collisions at $ \sqrt{s} = $ 13 TeV	JHEP 08 (2018) 113	CMS-HIG-16-018 1805.12191
16	ATLAS Collaboration	Constraints on mediator-based dark matter and scalar dark energy models using $ \sqrt s = $ 13 TeV $ pp $ collision data collected by the ATLAS detector	JHEP 05 (2019) 142	1903.01400
17	CMS Collaboration	The CMS trigger system	JINST 12 (2017) P01020	CMS-TRG-12-001 1609.02366
18	CMS Collaboration	The CMS Experiment at the CERN LHC	JINST 3 (2008) S08004
19	CMS Collaboration	Measurement of the inelastic proton-proton cross section at $ \sqrt{s}= $ 13 TeV	JHEP 07 (2018) 161	CMS-FSQ-15-005 1802.02613
20	LHC Dark Matter Working Group Collaboration	LHC Dark Matter Working Group: Next-generation spin-0 dark matter models	Phys. Dark Univ. 27 (2020) 100351	1810.09420
21	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
22	S. Frixione, P. Nason, and C. Oleari	Matching NLO QCD computations with Parton Shower simulations: the POWHEG method	JHEP 11 (2007) 070	0709.2092
23	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
24	T. Sjöstrand et al.	An introduction to pythia 8.2	Computer Physics Communications 191 (2015) 159	1410.3012
25	NNPDF Collaboration	Parton distributions for the LHC Run II	JHEP 04 (2015) 040	1410.8849
26	CMS Collaboration	Event generator tunes obtained from underlying event and multiparton scattering measurements	EPJC 76 (2016) 155	CMS-GEN-14-001 1512.00815
27	P. Skands, S. Carrazza, and J. Rojo	Tuning PYTHIA 8.1: the Monash 2013 tune	EPJC 74 (2014) 3024	1404.5630
28	GEANT4 Collaboration	GEANT 4---a simulation toolkit	NIM A 506 (2003) 250
29	CMS Collaboration	Particle-flow reconstruction and global event description with the CMS detector	JINST 12 (2017) P10003	CMS-PRF-14-001 1706.04965
30	M. Cacciari, G. P. Salam, and G. Soyez	The anti-$ k_{\mathrm{T}} $ jet clustering algorithm	JHEP 04 (2008) 063	0802.1189
31	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
32	CMS Collaboration	Pileup mitigation at CMS in 13 TeV data	JINST 15 (2020) P09018	CMS-JME-18-001 2003.00503
33	CMS Collaboration	Performance of missing transverse momentum reconstruction in proton-proton collisions at $ \sqrt{s} = $ 13\,TeV using the CMS detector	JINST 14 (2019) P07004	CMS-JME-17-001 1903.06078
34	CMS Collaboration	Performance of reconstruction and identification of $ \tau $ leptons decaying to hadrons and $ \nu_\tau $ in pp collisions at $ \sqrt{s}= $ 13 TeV	JINST 13 (2018) P10005	CMS-TAU-16-003 1809.02816
35	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
36	A. J. Barr	Measuring slepton spin at the LHC	JHEP 02 (2006) 042	hep-ph/0511115
37	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
38	CMS Collaboration	CMS luminosity measurement for the 2017 data-taking period at $ \sqrt{s} = $ 13 TeV	CMS Physics Analysis Summary, 2018 link	CMS-PAS-LUM-17-004
39	CMS Collaboration	CMS luminosity measurement for the 2018 data-taking period at $ \sqrt{s} = $ 13 TeV	CMS Physics Analysis Summary, 2019 link	CMS-PAS-LUM-18-002
40	CMS Collaboration	Measurements of Inclusive $ W $ and $ Z $ Cross Sections in $ pp $ Collisions at $ \sqrt{s}= $ 7 TeV	JHEP 01 (2011) 080	CMS-EWK-10-002 1012.2466
41	CMS Collaboration	Observation of the associated production of a single top quark and a $ W $ boson in $ pp $ collisions at $ \sqrt s = $8 TeV	PRL 112 (2014) 231802	CMS-TOP-12-040 1401.2942
42	CMS Collaboration	Measurement of the ZZ production cross section and Z $ \to \ell^+\ell^-\ell'^+\ell'^- $ branching fraction in pp collisions at $ \sqrt s $=13 TeV	[Erratum: Phys.Lett.B 772, 884--884 ()], 2016 PLB 763 (2016) 280	CMS-SMP-16-001 1607.08834
43	CMS Collaboration	Measurement of the inclusive and differential WZ production cross sections, polarization angles, and triple gauge couplings in pp collisions at $ \sqrt{s} = $ 13 TeV	JHEP 07 (2022) 032	CMS-SMP-20-014 2110.11231
44	LHC Higgs Cross Section Working Group Collaboration	Handbook of LHC Higgs Cross Sections: 3. Higgs Properties	link	1307.1347
45	A. L. Read	Presentation of search results: the CL$ _{s} $ technique	no.~10, 2693, 2002 JPG 28 (2002)
46	T. Junk	Confidence level computation for combining searches with small statistics	NIM A 434 (1999) 435	hep-ex/9902006
47	G. Cowan, K. Cranmer, E. Gross, and O. Vitells	Asymptotic formulae for likelihood-based tests of new physics	EPJC 71 (2011) 1554	1007.1727