CMS-PAS-FTR-18-035

CMS-PAS-FTR-18-035
Projection of searches for exotic Higgs boson decays to light pseudoscalars for the High-Luminosity LHC
CMS Collaboration
February 2019

Abstract: This Physics Analysis Summary details the projections of two searches for exotic decays of the Higgs boson from LHC Run 2 to the High-Luminosity LHC. Decays to a pair of light pseudoscalar bosons are explored, in the final states of two $\tau$ leptons and two muons, or two $\tau$ leptons and two b quarks. The projections are based on analyses that use 35.9 fb $^{-1}$ proton-proton collision data recorded at a center-of-mass energy of 13 TeV in 2016. Integrated luminosities of up to 3000 fb $^{-1}$ are considered in the projections, with different scenarios for the extrapolation of the systematic uncertainties.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ;

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: Left: Projected expected limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}})$ times the branching fraction for ${\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}} \to 2 {\mathrm {b}}2 {\tau}$ , for 36, 300, and 3000 fb $^{-1}$ . Right: Projected expected limits $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}}) \mathcal {B}({{{\mathrm {h}}}\to {{\mathrm {a}} {\mathrm {a}}}\to 2 {\tau}2{{\mathrm {b}}}})$ , comparing different scenarios for systematic uncertainties for an integrated luminosity of 3000 fb $^{-1}$ .
png pdf	Figure 1-a: Projected expected limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}})$ times the branching fraction for ${\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}} \to 2 {\mathrm {b}}2 {\tau}$ , for 36, 300, and 3000 fb $^{-1}$ .
png pdf	Figure 1-b: Projected expected limits $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}}) \mathcal {B}({{{\mathrm {h}}}\to {{\mathrm {a}} {\mathrm {a}}}\to 2 {\tau}2{{\mathrm {b}}}})$ , comparing different scenarios for systematic uncertainties for an integrated luminosity of 3000 fb $^{-1}$ .
png pdf	Figure 2: Expected upper limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}}) \mathcal {B}({\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}})$ for 3000 fb $^{-1}$ of data with YR18 systematic uncertainties for the $2 {\mathrm {b}}2 {\tau}$ final state in 2HDM+S type-1 (top left), type-2 (top right), type-3 (bottom left), and type-4 (bottom right).
png pdf	Figure 2-a: Expected upper limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}}) \mathcal {B}({\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}})$ for 3000 fb $^{-1}$ of data with YR18 systematic uncertainties for the $2 {\mathrm {b}}2 {\tau}$ final state in 2HDM+S type-1.
png pdf	Figure 2-b: Expected upper limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}}) \mathcal {B}({\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}})$ for 3000 fb $^{-1}$ of data with YR18 systematic uncertainties for the $2 {\mathrm {b}}2 {\tau}$ final state in 2HDM+S type-2.
png pdf	Figure 2-c: Expected upper limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}}) \mathcal {B}({\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}})$ for 3000 fb $^{-1}$ of data with YR18 systematic uncertainties for the $2 {\mathrm {b}}2 {\tau}$ final state in 2HDM+S type-3.
png pdf	Figure 2-d: Expected upper limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}}) \mathcal {B}({\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}})$ for 3000 fb $^{-1}$ of data with YR18 systematic uncertainties for the $2 {\mathrm {b}}2 {\tau}$ final state in 2HDM+S type-4.
png pdf	Figure 3: Left: Projected expected limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}}) \mathcal {B}({{{\mathrm {h}}}\to {{\mathrm {a}} {\mathrm {a}}}\to 2 {{\mu}}2{{\tau}}})$ , for 36, 300, and 3000 fb $^{-1}$ . Right: Projected expected limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}}) \mathcal {B}({{{\mathrm {h}}}\to {{\mathrm {a}} {\mathrm {a}}}\to 2 {{\mu}}2{{\tau}}})$ , comparing different scenarios for systematic uncertainties for an integrated luminosity of 3000 fb $^{-1}$ .
png pdf	Figure 3-a: Projected expected limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}}) \mathcal {B}({{{\mathrm {h}}}\to {{\mathrm {a}} {\mathrm {a}}}\to 2 {{\mu}}2{{\tau}}})$ , for 36, 300, and 3000 fb $^{-1}$ .
png pdf	Figure 3-b: Projected expected limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}}) \mathcal {B}({{{\mathrm {h}}}\to {{\mathrm {a}} {\mathrm {a}}}\to 2 {{\mu}}2{{\tau}}})$ , comparing different scenarios for systematic uncertainties for an integrated luminosity of 3000 fb $^{-1}$ .
png pdf	Figure 4: Expected upper limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}})\mathcal {B}({\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}})$ for 3000 fb $^{-1}$ of data with YR18 systematic uncertainties for the $2 {{\mu}}2 {\tau}$ final state in 2HDM+S type-1 (top left), type-2 (top right), type-3 (bottom left), and type-4 (bottom right).
png pdf	Figure 4-a: Expected upper limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}})\mathcal {B}({\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}})$ for 3000 fb $^{-1}$ of data with YR18 systematic uncertainties for the $2 {{\mu}}2 {\tau}$ final state in 2HDM+S type-1.
png pdf	Figure 4-b: Expected upper limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}})\mathcal {B}({\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}})$ for 3000 fb $^{-1}$ of data with YR18 systematic uncertainties for the $2 {{\mu}}2 {\tau}$ final state in 2HDM+S type-2.
png pdf	Figure 4-c: Expected upper limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}})\mathcal {B}({\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}})$ for 3000 fb $^{-1}$ of data with YR18 systematic uncertainties for the $2 {{\mu}}2 {\tau}$ final state in 2HDM+S type-3.
png pdf	Figure 4-d: Expected upper limits on $(\sigma ({\mathrm {h}})/\sigma _{\textrm {SM}})\mathcal {B}({\mathrm {h}} \to {\mathrm {a}} {\mathrm {a}})$ for 3000 fb $^{-1}$ of data with YR18 systematic uncertainties for the $2 {{\mu}}2 {\tau}$ final state in 2HDM+S type-4.

Tables
png pdf	Table 1: The sources of systematic uncertainty for which limiting values are applied in the ''YR18 systematics uncertainties'' scenario. Systematic uncertainties of the reference Run 2 analyses are described in Refs. [1,2].

Summary

Recent searches for exotic decays of the Higgs boson performed with 35.9 fb

$^{-1}$ of data collected at 13 TeV [1,2] have been projected to integrated luminosities of up to 3000 fb

$^{-1}$ , achievable at the High-Luminosity LHC. They target decays of the Higgs boson to a pair of light pseudoscalars in the final states with two

$\tau$ leptons and two muons, or two

$\mathrm{b}$ quarks and two muons. The integrated luminosity of 3000 fb

$^{-1}$ will improve the sensitivity by about an order of magnitude for the search in the

$2\mathrm{b}2\tau$ final state. The improvement is larger in the

$2{\mu}2\tau$ final state and scales almost linearly with the integrated luminosity for pseudoscalar masses close to 15 GeV.

References
1	CMS Collaboration	Search for an exotic decay of the Higgs boson to a pair of light pseudoscalars in the final state with two b quarks and two $\tau$ leptons in proton-proton collisions at $\sqrt{s}=$ 13 TeV	PLB 785 (2018) 462	CMS-HIG-17-024 1805.10191
2	CMS Collaboration	Search for an exotic decay of the Higgs boson to a pair of light pseudoscalars in the final state of two muons and two $\tau$ leptons in proton-proton collisions at $\sqrt{s}=$ 13 TeV	JHEP 11 (2018) 018	CMS-HIG-17-029 1805.04865
3	D. Curtin et al.	Exotic decays of the 125 GeV Higgs boson	PRD 90 (2014) 075004	1312.4992
4	CMS Collaboration	The CMS Experiment at the CERN LHC	JINST 3 (2008) S08004	CMS-00-001
5	G. Apollinari, B. O., T. Nakamoto, and L. Rossi	High Luminosity Large Hadron Collider HL-LHC	CERN Yellow Report (2015), no. 5, 1	1705.08830
6	D. Contardo et al.	Technical Proposal for the Phase-II Upgrade of the CMS Detector	CERN-LHCC-2015-010, LHCC-P-008, CMS-TDR-15-02
7	K. Klein	The Phase-2 Upgrade of the CMS Tracker	CERN-LHCC-2017-009, CMS-TDR-014
8	CMS Collaboration	The Phase-2 Upgrade of the CMS Barrel Calorimeters Technical Design Report	CDS
9	CMS Collaboration	The Phase-2 Upgrade of the CMS Endcap Calorimeter	CDS
10	CMS Collaboration	The Phase-2 Upgrade of the CMS Muon Detectors	CDS
11	CMS Collaboration	Expected performance of the physics objects with the upgraded CMS detector at the HL-LHC	CDS