${{\mathit H}^{\pm\pm}}$ (doubly-charged Higgs boson) mass limits

This section covers searches for a doubly-charged Higgs boson with couplings to lepton pairs. Its weak isospin ${{\mathit T}_{{{3}}}}$ is thus restricted to two possibilities depending on lepton chiralities: ${{\mathit T}_{{{3}}}}({{\mathit H}^{\pm\pm}}$) = $\pm{}$1, with the coupling ${{\mathit g}}_{{{\mathit \ell}} {{\mathit \ell}}}$ to ${{\mathit \ell}_{{{L}}}^{-}}{{\mathit \ell}_{{{L}}}^{'-}}$ and ${{\mathit \ell}_{{{R}}}^{+}}{{\mathit \ell}_{{{R}}}^{'+}}$ (``left-handed'') and ${{\mathit T}_{{{3}}}}({{\mathit H}^{\pm\pm}}$) = 0, with the coupling to ${{\mathit \ell}_{{{R}}}^{-}}{{\mathit \ell}_{{{R}}}^{'-}}$ and ${{\mathit \ell}_{{{L}}}^{+}}{{\mathit \ell}_{{{L}}}^{'+}}$ (``right-handed''). These Higgs bosons appear in some left-right symmetric models based on the gauge group SU(2)$_{L}{\times }SU(2)_{R}{\times }$U(1), the type-II seesaw model, and the Zee-Babu model. The two cases are listed separately in the following. Unless noted, one of the lepton flavor combinations is assumed to be dominant in the decay.

Limits for ${{\mathit H}^{\pm\pm}}$ with $\mathit T_{3}$ = 0

INSPIRE   PDGID:
S064HD0
VALUE (GeV) CL% DOCUMENT ID TECN  COMMENT
$> 900$ 95 1
AAD
2023AI
 ATLS ${{\mathit \ell}}{{\mathit \ell}}$
$> 58$ 95 2
AABOUD
2018BC
 ATLS ${{\mathit e}}{{\mathit e}}$
$> 723$ 95 2
AABOUD
2018BC
 ATLS ${{\mathit \mu}}{{\mathit \mu}}$
$>402$ 95 3
AAD
2015AG
 ATLS ${{\mathit e}}{{\mathit \mu}}$
$>290$ 95 4
AAD
2015AP
 ATLS ${{\mathit e}}{{\mathit \tau}}$
$>290$ 95 4
AAD
2015AP
 ATLS ${{\mathit \mu}}{{\mathit \tau}}$
$>97.3$ 95 5
ABDALLAH
2003
DLPH ${{\mathit \tau}}{{\mathit \tau}}$
$>97.3$ 95 6
ACHARD
2003F
 L3 ${{\mathit \tau}}{{\mathit \tau}}$
$>98.5$ 95 7
ABBIENDI
2002C
 OPAL ${{\mathit \tau}}{{\mathit \tau}}$
• • We do not use the following data for averages, fits, limits, etc. • •
$>374$ 95 3
AAD
2015AG
 ATLS ${{\mathit e}}{{\mathit e}}$
$>438$ 95 3
AAD
2015AG
 ATLS ${{\mathit \mu}}{{\mathit \mu}}$
$> 251$ 95 8
AAD
2012AY
 ATLS ${{\mathit \mu}}{{\mathit \mu}}$
$> 306$ 95 9
AAD
2012CQ
 ATLS ${{\mathit \mu}}{{\mathit \mu}}$
$> 310$ 95 9
AAD
2012CQ
 ATLS ${{\mathit e}}{{\mathit \mu}}$
$> 322$ 95 9
AAD
2012CQ
 ATLS ${{\mathit e}}{{\mathit e}}$
$> 113$ 95 10
ABAZOV
2012A
 D0 ${{\mathit \mu}}{{\mathit \tau}}$
$> 205$ 95 11
AALTONEN
2011AF
 CDF ${{\mathit \mu}}{{\mathit \mu}}$
$> 190$ 95 11
AALTONEN
2011AF
 CDF ${{\mathit e}}{{\mathit \mu}}$
$> 205$ 95 11
AALTONEN
2011AF
 CDF ${{\mathit e}}{{\mathit e}}$
$> 145$ 95 12
ABAZOV
2008V
 D0 ${{\mathit \mu}}{{\mathit \mu}}$
13
AKTAS
2006A
 H1 single ${{\mathit H}^{\pm\pm}}$
$> 109$ 95 14
ACOSTA
2005L
 CDF stable
$>98.2$ 95 15
ABAZOV
2004E
 D0 ${{\mathit \mu}}{{\mathit \mu}}$
16
ABBIENDI
2003Q
 OPAL $\mathit E_{{\mathrm {cm}}}{}\leq{}$209 GeV, single ${{\mathit H}^{\pm\pm}}$
17
GORDEEV
1997
SPEC muonium conversion
$>45.6$ 95 18
ACTON
1992M
 OPAL
$>25.5$ 95 19
ACTON
1992M
 OPAL
$\text{none 7.3 - 34.3}$ 95 20
SWARTZ
1990
MRK2
1  AAD 2023AI search for ${{\mathit H}^{++}}{{\mathit H}^{--}}$ production using 139 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 13 TeV. Decay branching ratios B( ${{\mathit H}^{++}}$ $\rightarrow$ ${{\mathit \ell}^{+}}{{\mathit \ell}^{'+}}$) for the six flavor combinations are assumed to be equal, adding up to unity.
2  See their Figs. 12(b) and 14 for limits with smaller branching ratios.
3  AAD 2015AG search for ${{\mathit H}^{++}}{{\mathit H}^{--}}$ production in 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 8 TeV. The limit assumes 100$\%$ branching ratio to the specified final state. See their Fig. 5 for limits for arbitrary branching ratios.
4  AAD 2015AP search for ${{\mathit H}^{++}}{{\mathit H}^{--}}$ production in 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 8 TeV. The limit assumes 100$\%$ branching ratio to the specified final state.
5  ABDALLAH 2003 search for ${{\mathit H}^{++}}{{\mathit H}^{--}}$ pair production either followed by ${{\mathit H}^{++}}$ $\rightarrow$ ${{\mathit \tau}^{+}}{{\mathit \tau}^{+}}$, or decaying outside the detector.
6  ACHARD 2003F search for ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit H}^{++}}{{\mathit H}^{--}}$ with ${{\mathit H}^{\pm\pm}}$ $\rightarrow$ ${{\mathit \ell}^{\pm}}{{\mathit \ell}^{'\pm}}$. The limit holds for ${{\mathit \ell}}$ = ${{\mathit \ell}^{\,'}}$ = ${{\mathit \tau}}$, and slightly different limits apply for other flavor combinations. The limit is valid for $\mathit g_{{{\mathit \ell}} {{\mathit \ell}^{\,'}}}{ {}\gtrsim{} }$ $10^{-7}$.
7  ABBIENDI 2002C searches for pair production of ${{\mathit H}^{++}}{{\mathit H}^{--}}$, with ${{\mathit H}^{\pm\pm}}$ $\rightarrow$ ${{\mathit \ell}^{\pm}}{{\mathit \ell}^{\pm}}$ (${{\mathit \ell}},{{\mathit \ell}^{\,'}}$ = ${{\mathit e}},{{\mathit \mu}},{{\mathit \tau}}$). the limit holds for ${{\mathit \ell}}={{\mathit \ell}^{\,'}}={{\mathit \tau}}$, and becomes stronger for other combinations of leptonic final states. To ensure the decay within the detector, the limit only applies for $\mathit g({{\mathit H}}{{\mathit \ell}}{{\mathit \ell}}){ {}\gtrsim{} }10^{-7}$.
8  AAD 2012AY search for ${{\mathit H}^{++}}{{\mathit H}^{--}}$ production with 1.6 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 7 TeV. The limit assumes 100$\%$ branching ratio to the specified final state.
9  AAD 2012CQ search for ${{\mathit H}^{++}}{{\mathit H}^{--}}$ production with 4.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 7 TeV. The limit assumes 100$\%$ branching ratio to the specified final state. See their Table 1 for limits assuming smaller branching ratios.
10  ABAZOV 2012A search for ${{\mathit H}^{++}}{{\mathit H}^{--}}$ production in 7.0 fb${}^{-1}$ of ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 1.96 TeV.
11  AALTONEN 2011AF search for ${{\mathit H}^{++}}{{\mathit H}^{--}}$ production in 6.1 fb${}^{-1}$ of ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\mathit E_{{\mathrm {cm}}}$ = 1.96 TeV.
12  ABAZOV 2008V search for ${{\mathit H}^{++}}{{\mathit H}^{--}}$ production in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\mathit E_{{\mathrm {cm}}}$= 1.96 TeV. The limit is for B( ${{\mathit H}}$ $\rightarrow$ ${{\mathit \mu}}{{\mathit \mu}}$) = 1. The limit is updated in ABAZOV 2012A.
13  AKTAS 2006A search for single ${{\mathit H}^{\pm\pm}}$ production in ${{\mathit e}}{{\mathit p}}$ collisions at HERA. Assuming that ${{\mathit H}^{++}}$ only couples to ${{\mathit e}^{+}}{{\mathit \mu}^{+}}$ with $\mathit g_{{{\mathit e}} {{\mathit \mu}}}$ = 0.3 (electromagnetic strength), a limit ${\mathit m}_{{{\mathit H}^{++}}}$ $>$ 141 GeV (95$\%$ CL) is derived. For the case where ${{\mathit H}^{++}}$ couples to ${{\mathit e}}{{\mathit \tau}}$ only the limit is 112 GeV.
14  ACOSTA 2005L search for ${{\mathit H}^{{++}}}{{\mathit H}^{{--}}}$ pair production in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions. The limit is valid for ${{\mathit g}}_{{{\mathit \ell}} {{\mathit \ell}^{\,'}}}$ $<$ $10^{-8}$ so that the Higgs decays outside the detector.
15  ABAZOV 2004E search for ${{\mathit H}^{++}}{{\mathit H}^{--}}$ pair production in ${{\mathit H}^{\pm\pm}}$ $\rightarrow$ ${{\mathit \mu}^{\pm}}{{\mathit \mu}^{\pm}}$. The limit is valid for $\mathit g_{{{\mathit \mu}} {{\mathit \mu}}}{ {}\gtrsim{} }$ $10^{-7}$.
16  ABBIENDI 2003Q searches for single ${{\mathit H}^{\pm\pm}}$ via direct production in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit e}^{\mp}}{{\mathit e}^{\mp}}{{\mathit H}^{\pm\pm}}$, and via ${{\mathit t}}$-channel exchange in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$. In the direct case, and assuming B( ${{\mathit H}^{\pm\pm}}$ $\rightarrow$ ${{\mathit \ell}^{\pm}}{{\mathit \ell}^{\pm}}$) = 1, a 95$\%$ CL limit on ${{\mathit h}}_{ee}$ $<$ 0.071 is set for ${\mathit m}_{{{\mathit H}^{\pm\pm}}}$ $<$ 160 GeV (see Fig. 6). In the second case, indirect limits on ${{\mathit h}}_{ee}$ are set for ${\mathit m}_{{{\mathit H}^{\pm\pm}}}$ $<$ 2 TeV (see Fig. 8).
17  GORDEEV 1997 search for muonium-antimuonium conversion and find $\mathit G_{{{\mathit M}} {{\overline{\mathit M}}}}/\mathit G_{\mathit F}<0.14$ (90$\%~$ CL), where $\mathit G_{{{\mathit M}} {{\overline{\mathit M}}}}$ is the lepton-flavor violating effective four-fermion coupling. This limit may be converted to ${\mathit m}_{{{\mathit H}^{++}}}>210$ GeV if the Yukawa couplings of ${{\mathit H}^{++}}$ to and ${{\mathit \mu}}{{\mathit \mu}}$ are as large as the weak gauge coupling. For similar limits on muonium-antimuonium conversion, see the muon Particle Listings.
18  ACTON 1992M limit assumes ${{\mathit H}^{\pm\pm}}$ $\rightarrow$ ${{\mathit \ell}^{\pm}}{{\mathit \ell}^{\pm}}$ or ${{\mathit H}^{\pm\pm}}$ does not decay in the detector. Thus the region $\mathit g_{{{\mathit \ell}} {{\mathit \ell}}}\approx{}10^{-7}$ is not excluded.
19  ACTON 1992M from $\Delta \Gamma _{{{\mathit Z}}}<$40 MeV.
20  SWARTZ 1990 assume ${{\mathit H}^{\pm\pm}}$ $\rightarrow$ ${{\mathit \ell}^{\pm}}{{\mathit \ell}^{\pm}}$ (any flavor). The limits are valid for the Higgs-lepton coupling g(${{\mathit H}}{{\mathit \ell}}{{\mathit \ell}}$) ${ {}\gtrsim{} }$ $7.4 \times 10^{-7}/[{\mathit m}_{{{\mathit H}}}$/GeV]${}^{1/2}$. The limits improve somewhat for ${{\mathit e}}{{\mathit e}}$ and ${{\mathit \mu}}{{\mathit \mu}}$ decay modes.
References