CMS-PAS-HIG-15-009

CMS-PAS-HIG-15-009
Search for a light pseudo-scalar Higgs boson produced in association with bottom quarks in pp collisions at $\sqrt{s} =$ 8 TeV
CMS Collaboration
October 2016

Abstract: We report on the search for a light pseudo-scalar Higgs boson produced in association with a bottom quark and decaying into dimuons. The search makes use of 19.8 fb $^{-1}$ of proton-proton collisions at a center-of-mass energy of 8 TeV, collected by the CMS experiment at the LHC. No signal is observed in the search for a pseudo-scalar Higgs boson and upper limits on the cross section times branching fraction are set.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; These preliminary results are superseded in this paper, JHEP 11 (2017) 010. The superseded preliminary plots can be found here.

Figures	Summary	References	CMS Publications

Figures
png pdf	Figure 1: The transverse momentum of the leading (left) and the subleading (right) ${p_{\mathrm {T}}}$ muon.
png pdf	Figure 1-a: The transverse momentum of the leading ${p_{\mathrm {T}}}$ muon.
png pdf	Figure 1-b: The transverse momentum of the subleading ${p_{\mathrm {T}}}$ muon.
png pdf	Figure 2: Left: the transverse momentum of the leading ${p_{\mathrm {T}}}$ bottom-quark tagged jet. Right: the missing transverse energy (MET).
png pdf	Figure 2-a: The transverse momentum of the leading ${p_{\mathrm {T}}}$ bottom-quark tagged jet.
png pdf	Figure 2-b: The missing transverse energy (MET).
png pdf	Figure 3: The dimuon mass with the expected background event yield and its uncertainty and with the expected signal for $\rm m_{A}=$ 30 GeV assuming the signal cross section times branching fraction of 350 fb. Left: with the use of PF jets; right: with the use of JPT jets.
png pdf	Figure 3-a: The dimuon mass with the expected background event yield and its uncertainty and with the expected signal for $\rm m_{A}=$ 30 GeV assuming the signal cross section times branching fraction of 350 fb, with the use of PF jets.
png pdf	Figure 3-b: The dimuon mass with the expected background event yield and its uncertainty and with the expected signal for $\rm m_{A}=$ 30 GeV assuming the signal cross section times branching fraction of 350 fb, with the use of JPT jets.
png pdf	Figure 4: Cross-check with the $\rm e^{+}e^{-}$ final state. The dielectron mass spectrum with the expected background event yield and its uncertainty.
png pdf	Figure 5: Left: the dimuon mass with the post-fit background event yield and its uncertainty given by the fit and the expected signal for $\rm m_{A}=$ 30 GeV assuming the signal cross section times branching fraction of 350 fb. Right: the expected and observed upper limit at 95% CL on $\sigma (\mathrm {pp \rightarrow b\bar{b}A)} \times \mathcal {B} \mathrm {(A}\rightarrow \mu \mu )$ as a function of the dimuon mass. The circles show the limits obtained in the CMS analysis of the $\mathrm {A}\rightarrow \tau \tau$ final state [7] and recalculated into the limits for the $\mathrm {A}\rightarrow \mu \mu$ final state using Eq.(1).
png pdf	Figure 5-a: The dimuon mass with the post-fit background event yield and its uncertainty given by the fit and the expected signal for $\rm m_{A}=$ 30 GeV assuming the signal cross section times branching fraction of 350 fb.
png pdf	Figure 5-b: The expected and observed upper limit at 95% CL on $\sigma (\mathrm {pp \rightarrow b\bar{b}A)} \times \mathcal {B} \mathrm {(A}\rightarrow \mu \mu )$ as a function of the dimuon mass. The circles show the limits obtained in the CMS analysis of the $\mathrm {A}\rightarrow \tau \tau$ final state [7] and recalculated into the limits for the $\mathrm {A}\rightarrow \mu \mu$ final state using Eq.(1).
png pdf	Figure 6: The transverse momentum of the leading (left) and the subleading (right) ${p_{\mathrm {T}}}$ muon.
png pdf	Figure 6-a: The transverse momentum of the leading ${p_{\mathrm {T}}}$ muon.
png pdf	Figure 6-b: The transverse momentum of the subleading ${p_{\mathrm {T}}}$ muon.
png pdf	Figure 7: Left: the transverse momentum of the leading ${p_{\mathrm {T}}}$ bottom-quark tagged jet. Right: the missing transverse energy (MET).
png pdf	Figure 7-a: The transverse momentum of the leading ${p_{\mathrm {T}}}$ bottom-quark tagged jet.
png pdf	Figure 7-b: The missing transverse energy (MET).
png pdf	Figure 8: The dimuon mass with the expected background event yield and its uncertainty and with the expected signal for $\rm m_{A}=$ 30 GeV assuming the signal cross section times branching fraction of 350 fb. Left: with the use of PF jets; right: with the use of JPT jets.
png pdf	Figure 8-a: The dimuon mass with the expected background event yield and its uncertainty and with the expected signal for $\rm m_{A}=$ 30 GeV assuming the signal cross section times branching fraction of 350 fb, with the use of PF jets.
png pdf	Figure 8-b: The dimuon mass with the expected background event yield and its uncertainty and with the expected signal for $\rm m_{A}=$ 30 GeV assuming the signal cross section times branching fraction of 350 fb, with the use of JPT jets.
png pdf	Figure 9: Cross-check with the $\rm e^{+}e^{-}$ final state. The dielectron mass spectrum with the expected background event yield and its uncertainty.
png pdf	Figure 10: Left: the dimuon mass with the post-fit background event yield and its uncertainty given by the fit and the expected signal for $\rm m_{A}=30 GeV$ assuming the signal cross section times branching fraction of 350 fb. Right: the expected and observed upper limit at 95% CL on $\sigma (\mathrm {pp \rightarrow b\bar{b}A)} \times \mathcal {B} \mathrm {(A}\rightarrow \mu \mu )$ as a function of the dimuon mass. The circles show the limits obtained in the CMS analysis of the $\mathrm {A}\rightarrow \tau \tau$ final state [7] and recalculated into the limits for the $\mathrm {A}\rightarrow \mu \mu$ final state using formula $\frac {\mathcal {B}\mathrm {(A}\rightarrow \tau \tau )}{\mathcal {B}\mathrm {(A}\rightarrow \mu \mu )}= [ m_{\tau} / m_{\mu} ]^2$ .
png pdf	Figure 10-a: The dimuon mass with the post-fit background event yield and its uncertainty given by the fit and the expected signal for $\rm m_{A}=30 GeV$ assuming the signal cross section times branching fraction of 350 fb.
png pdf	Figure 10-b: The expected and observed upper limit at 95% CL on $\sigma (\mathrm {pp \rightarrow b\bar{b}A)} \times \mathcal {B} \mathrm {(A}\rightarrow \mu \mu )$ as a function of the dimuon mass. The circles show the limits obtained in the CMS analysis of the $\mathrm {A}\rightarrow \tau \tau$ final state [7] and recalculated into the limits for the $\mathrm {A}\rightarrow \mu \mu$ final state using formula $\frac {\mathcal {B}\mathrm {(A}\rightarrow \tau \tau )}{\mathcal {B}\mathrm {(A}\rightarrow \mu \mu )}= [ m_{\tau} / m_{\mu} ]^2$ .

Summary

A light pseudo-scalar Higgs boson produced in association with a pair of b-jets and decaying into two muons has been searched for in pp collisions at

$\sqrt{s} =$ 8 TeV with an integrated luminosity of 19.8 fb

$^{-1}$ . No signal has been observed in the dimuon mass region of 25-60 GeV. Upper limits on the cross section times branching fraction,

$\sigma(\mathrm{pp \rightarrow b\bar{b}A)} \times \mathcal{B}\mathrm{(A}\rightarrow\mu\mu)$ obtained have been set. The limits evaluated from the direct search for the

$\mathrm{A} \rightarrow \mu\mu$ decay in the associated

$\rm b \bar{b} A$ production are comparable with the upper limits from the search for the

$\mathrm{A}\rightarrow\tau\tau$ final state from the same production process. It demonstrates the importance of the

$\mu\mu$ final state for the overal experimental sensitivity in searches for

$\rm b \bar{b}A$ production. This complementarity of the two final states can become particularly important should future larger data sets start revealing evidence of potential new physics.

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