MASS LIMITS FOR NEUTRAL HIGGS BOSONS IN EXTENDED HIGGS MODELS

This Section covers models which do not fit into either the Standard Model or its simplest minimal Supersymmetric extension (MSSM), leading to anomalous production rates, or nonstandard final states and branching ratios. In particular, this Section covers limits which may apply to generic two-Higgs-doublet models (2HDM), or to special regions of the MSSM parameter space where decays to invisible particles or to photon pairs are dominant (see the review on ``Status of Higgs Boson Physics''). Concerning the mass limits for ${{\mathit H}^{0}}$ and ${{\mathit A}^{0}}$ listed below, see the footnotes or the comment lines for details on the nature of the models to which the limits apply.
The observed signal at about 125 GeV, see section ``${{\mathit H}^{0}}$'', can be interpreted as one of the neutral Higgs bosons of an extended Higgs sector.

Mass Limits in General two-Higgs-doublet Models INSPIRE search

VALUE (GeV) CL% DOCUMENT ID TECN COMMENT
*** We do not use the following data for averages, fits, limits, etc ***
1
AAD 2015BK
ATLS ${{\mathit H}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit H}^{0}}{{\mathit H}^{0}}$
2
AAD 2015S
ATLS ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit H}^{0}}$
3
KHACHATRYAN 2015BB
CMS ${{\mathit H}_{{2}}^{0}}$ , ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
4
KHACHATRYAN 2015N
CMS ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit H}^{0}}$
5
AAD 2014M
ATLS ${{\mathit H}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit H}^{\pm}}{{\mathit W}^{\mp}}$ $\rightarrow$ ${{\mathit H}^{0}}{{\mathit W}^{\pm}}{{\mathit W}^{\mp}}$ , ${{\mathit H}^{0}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}$
6
KHACHATRYAN 2014Q
CMS ${{\mathit H}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit H}^{0}}{{\mathit H}^{0}}$ , ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit H}^{0}}$
7
AALTONEN 2009AR
CDF ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit H}^{0}_{{{1,2}}}}$ $/$ ${{\mathit A}^{0}}{+}$ ${{\mathit X}}$ , ${{\mathit H}^{0}_{{{1,2}}}}$ $/$ ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$
$\text{none 1 - 55}$ 95 8
ABBIENDI 2005A
OPAL ${{\mathit H}_{{1}}^{0}}$, Type II model
>$ 110.6$ 95 9
ABDALLAH 2005D
DLPH ${{\mathit H}^{0}}$ $\rightarrow$ 2 jets
10
ABDALLAH 2004O
DLPH ${{\mathit Z}}$ $\rightarrow$ ${{\mathit f}}{{\overline{\mathit f}}}{{\mathit H}}$
11
ABDALLAH 2004O
DLPH ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit H}^{0}}{{\mathit Z}}$ , ${{\mathit H}^{0}}{{\mathit A}^{0}}$
12
ABBIENDI 2002D
OPAL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit H}}$
$\text{none 1 - 44}$ 95 13
ABBIENDI 2001E
OPAL ${{\mathit H}_{{1}}^{0}}$, Type-II model
>$68.0$ 95 14
ABBIENDI 1999E
OPAL tan $\beta >1$
15
ABREU 1995H
DLPH ${{\mathit Z}}$ $\rightarrow$ ${{\mathit H}^{0}}{{\mathit Z}^{*}}$ , ${{\mathit H}^{0}}{{\mathit A}^{0}}$
16
PICH 1992
RVUE Very light Higgs
1  AAD 2015BK search for production of a heavy ${{\mathit H}_{{2}}^{0}}$ decaying to ${{\mathit H}^{0}}{{\mathit H}^{0}}$ in the final state ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit b}}{{\overline{\mathit b}}}$ in 19.5 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 8 TeV. See their Figs. $15 - 18$ for excluded regions in the parameter space.
2  AAD 2015S search for production of ${{\mathit A}^{0}}$ decaying to ${{\mathit Z}}$ ${{\mathit H}^{0}}$ $\rightarrow$ ${{\mathit \ell}^{+}}{{\mathit \ell}^{-}}{{\mathit b}}{{\overline{\mathit b}}}$ , ${{\mathit \nu}}{{\overline{\mathit \nu}}}{{\mathit b}}{{\overline{\mathit b}}}$ and ${{\mathit \ell}^{+}}{{\mathit \ell}^{-}}{{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ in 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 8 TeV. See their Figs. 4 and 5 for excluded regions in the parameter space.
3  KHACHATRYAN 2015BB search for ${{\mathit H}_{{2}}^{0}}$ , ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$ in 19.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 8 TeV. See their Fig. 10 for excluded regions in the two-Higgs-doublet model parameter space.
4  KHACHATRYAN 2015N search for production of ${{\mathit A}^{0}}$ decaying to ${{\mathit Z}}$ ${{\mathit H}^{0}}$ $\rightarrow$ ${{\mathit \ell}^{+}}{{\mathit \ell}^{-}}{{\mathit b}}{{\overline{\mathit b}}}$ in 19.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 8 TeV. See their Fig. 5 for excluded regions in the tan $\beta $ $−$ cos $(\beta −\alpha )$ plane for ${\mathit m}_{{{\mathit A}^{0}}}$ = 300 GeV.
5  AAD 2014M search for the decay cascade ${{\mathit H}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit H}^{\pm}}{{\mathit W}^{\mp}}$ $\rightarrow$ ${{\mathit H}^{0}}{{\mathit W}^{\pm}}{{\mathit W}^{\mp}}$ , ${{\mathit H}^{0}}$ decaying to ${{\mathit b}}{{\overline{\mathit b}}}$ in 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 8 TeV. See their Table IV for limits in a two-Higgs-doublet model for ${\mathit m}_{{{\mathit H}_{{2}}^{0}}}$= $325 - 1025$ GeV and ${\mathit m}_{{{\mathit H}^{+}}}$= $225 - 825$ GeV.
6  KHACHATRYAN 2014Q search for ${{\mathit H}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit H}^{0}}{{\mathit H}^{0}}$ and ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit H}^{0}}$ in 19.5 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 8 TeV. See their Figs. 4 and 5 for limits on cross section times branching ratio for ${{\mathit m}}_{{{\mathit H}_{{2}}},{{\mathit A}^{0}}}$= $260 - 360$ GeV and their Figs. $7 - 9$ for limits in two-Higgs-doublet models.
7  AALTONEN 2009AR search for Higgs bosons decaying to ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ in two doublet models in 1.8 fb${}^{-1}$ of ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 1.96 TeV. See their Fig. 2 for the limit on $\sigma \cdot{}$B( ${{\mathit H}^{0}_{{{1,2}}}}$ / ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ ) for different Higgs masses, and see their Fig. 3 for the excluded region in the MSSM parameter space.
8  ABBIENDI 2005A search for ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit H}_{{1}}^{0}}{{\mathit A}^{0}}$ in general Type-II two-doublet models, with decays ${{\mathit H}_{{1}}^{0}}$, ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}$ , ${{\mathit g}}{{\mathit g}}$ , ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ , and ${{\mathit H}_{{1}}^{0}}$ $\rightarrow$ ${{\mathit A}^{0}}{{\mathit A}^{0}}$ .
9  ABDALLAH 2005D search for ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit H}^{0}}{{\mathit Z}}$ and ${{\mathit H}^{0}}{{\mathit A}^{0}}$ with ${{\mathit H}^{0}}$, ${{\mathit A}^{0}}$ decaying to two jets of any flavor including ${{\mathit g}}{{\mathit g}}$ . The limit is for SM ${{\mathit H}^{0}}{{\mathit Z}}$ production cross section with B( ${{\mathit H}^{0}}$ $\rightarrow$ ${{\mathit j}}{{\mathit j}}$ ) = 1.
10  ABDALLAH 2004O search for ${{\mathit Z}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit H}^{0}}$ , ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit A}^{0}}$ , ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}{{\mathit H}^{0}}$ and ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}{{\mathit A}^{0}}$ in the final states 4 ${{\mathit b}}$ , ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ , and 4 ${{\mathit \tau}}$ . See paper for limits on Yukawa couplings.
11  ABDALLAH 2004O search for ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit H}^{0}}{{\mathit Z}}$ and ${{\mathit H}^{0}}{{\mathit A}^{0}}$ , with ${{\mathit H}^{0}}$, ${{\mathit A}^{0}}$ decaying to ${{\mathit b}}{{\overline{\mathit b}}}$ , ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ , or ${{\mathit H}^{0}}$ $\rightarrow$ ${{\mathit A}^{0}}{{\mathit A}^{0}}$ at $\mathit E_{{\mathrm {cm}}}$ = $189 - 208$ GeV. See paper for limits on couplings.
12  ABBIENDI 2002D search for ${{\mathit Z}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit H}_{{1}}^{0}}$ and ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit A}^{0}}$ with ${{\mathit H}_{{1}}^{0}}$ /${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ , in the range 4$<{\mathit m}_{{{\mathit H}}}<$12 GeV. See their Fig.$ $8 for limits on the Yukawa coupling.
13  ABBIENDI 2001E search for neutral Higgs bosons in general Type-II two-doublet models, at $\mathit E_{{\mathrm {cm}}}{}\leq{}$189 GeV. In addition to usual final states, the decays ${{\mathit H}_{{1}}^{0}}$, ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}$ , ${{\mathit g}}{{\mathit g}}$ are searched for. See their Figs.$ $15,16 for excluded regions.
14  ABBIENDI 1999E search for ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit H}^{0}}{{\mathit A}^{0}}$ and ${{\mathit H}^{0}}{{\mathit Z}}$ at $\mathit E_{{\mathrm {cm}}}$ = 183 GeV. The limit is with ${\mathit m}_{{{\mathit H}}}={\mathit m}_{{{\mathit A}}}$ in general two Higgs-doublet models. See their Fig.$ $18 for the exclusion limit in the ${\mathit m}_{{{\mathit H}}}-{\mathit m}_{{{\mathit A}}}$ plane. Updates the results of ACKERSTAFF 1998S.
15  See Fig.$ $4 of ABREU 1995H for the excluded region in the ${\mathit m}_{{{\mathit H}^{0}}}–{\mathit m}_{{{\mathit A}^{0}}}$ plane for general two-doublet models. For tan $\beta >$1, the region ${\mathit m}_{{{\mathit H}^{0}}}+{\mathit m}_{{{\mathit A}^{0}}}{ {}\lesssim{} }$87 GeV, ${\mathit m}_{{{\mathit H}^{0}}}<$47 GeV is excluded at 95$\%$ CL.
16  PICH 1992 analyse ${{\mathit H}^{0}}$ with ${\mathit m}_{{{\mathit H}^{0}}}<$ 2${\mathit m}_{{{\mathit \mu}}}$ in general two-doublet models. Excluded regions in the space of mass-mixing angles from LEP, beam dump, and ${{\mathit \pi}^{\pm}}$, ${{\mathit \eta}}$ rare decays are shown in Figs.$ $3,4. The considered mass region is not totally excluded.
References
AAD 2015BK
EPJ C75 412 Search for Higgs Boson Pair Production in the ${\mathit {\mathit b}}{\mathit {\overline{\mathit b}}}{\mathit {\mathit b}}{\mathit {\overline{\mathit b}}}$ Final State from ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
AAD 2015S
PL B744 163 Search for a $\mathit CP$-odd Higgs Boson Decaying to $\mathit Zh$ in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
KHACHATRYAN 2015BB
PL B750 494 Search for Diphoton Resonances in the Mass Range from 150 to 850 GeV in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV
KHACHATRYAN 2015N
PL B748 221 Search for a Pseudoscalar Boson Decaying into a ${{\mathit Z}}$ Boson and the 125 GeV Higgs Boson in ${{\mathit \ell}^{+}}{{\mathit \ell}^{-}}{\mathit {\mathit b}}{\mathit {\overline{\mathit b}}}$ Final States
AAD 2014M
PR D89 032002 Search for a Multi-Higgs-Boson Cascade in ${{\mathit W}^{+}}{{\mathit W}^{-}}{\mathit {\mathit b}}{\mathit {\overline{\mathit b}}}$ Events with the ATLAS Detector in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8  TeV
KHACHATRYAN 2014Q
PR D90 112013 Searches for Heavy Higgs Bosons in Two-Higgs-Doublet Models and for t $\rightarrow$ ch Decay using Multilepton and Diphoton Final States in ${{\mathit p}}{{\mathit p}}$ Collisions at 8 TeV
AALTONEN 2009AR
PRL 103 201801 Search for Higgs Bosons Predicted in Two-Higgs-Doublet Models via Decays to Tau Lepton Pairs in 1.96 TeV ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions
ABBIENDI 2005A
EPJ C40 317 Flavour-Independent $\mathit h{}^{0}\mathit A{}^{0}$ Search and Two Higgs Doublet Model Interpretation of Neutral Higgs Boson Searches at LEP
ABDALLAH 2005D
EPJ C44 147 Flavour Independent Searches for Hadronically Decaying Neutral Higgs Bosons
ABDALLAH 2004O
EPJ C38 1 Searches for Neutral Higgs Bosons in Extended Models
ABBIENDI 2002D
EPJ C23 397 Search for Yukawa Production of a Light Neutral Higgs Boson at LEP
ABBIENDI 2001E
EPJ C18 425 Two Higgs Doublet Model and Model Independent Interpretation of Neutral Higgs Boson Searches
ABBIENDI 1999E
EPJ C7 407 Search for Higgs Bosons in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at 183 GeV
ABREU 1995H
ZPHY C67 69 Search for Heavy Neutral Higgs Bosons in Two Doublet Models
PICH 1992
NP B388 31 Bounds on a Light Scalar in Two Higgs Doublet Models
ACKERSTAFF 1998S
EPJ C5 19 A Search for Neutral Higgs Bosons in the MSSM and Models with Two Scalar Field Doublets