# MASS LIMITS for ${{\boldsymbol H}^{\pm\pm}}$ (doubly-charged Higgs boson)

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 ${{\boldsymbol H}^{\pm\pm}}$ with $\boldsymbol T_{3}$ = 0 INSPIRE search

VALUE (GeV) CL% DOCUMENT ID TECN  COMMENT
$>374$ 95 1
 2015 AG
ATLS ${{\mathit e}}{{\mathit e}}$
$>402$ 95 1
 2015 AG
ATLS ${{\mathit e}}{{\mathit \mu}}$
$\bf{>438}$ 95 1
 2015 AG
ATLS ${{\mathit \mu}}{{\mathit \mu}}$
$>290$ 95 2
 2015 AP
ATLS ${{\mathit e}}{{\mathit \tau}}$
$>290$ 95 2
 2015 AP
ATLS ${{\mathit \mu}}{{\mathit \tau}}$
$>97.3$ 95 3
 2003
DLPH ${{\mathit \tau}}{{\mathit \tau}}$
$>97.3$ 95 4
 2003 F
L3 ${{\mathit \tau}}{{\mathit \tau}}$
$>98.5$ 95 5
 2002 C
OPAL ${{\mathit \tau}}{{\mathit \tau}}$
• • • We do not use the following data for averages, fits, limits, etc. • • •
$> 251$ 95 6
 2012 AY
ATLS ${{\mathit \mu}}{{\mathit \mu}}$
$> 306$ 95 7
 2012 CQ
ATLS ${{\mathit \mu}}{{\mathit \mu}}$
$> 310$ 95 7
 2012 CQ
ATLS ${{\mathit e}}{{\mathit \mu}}$
$> 322$ 95 7
 2012 CQ
ATLS ${{\mathit e}}{{\mathit e}}$
$> 113$ 95 8
 2012 A
D0 ${{\mathit \mu}}{{\mathit \tau}}$
$> 205$ 95 9
 2011 AF
CDF ${{\mathit \mu}}{{\mathit \mu}}$
$> 190$ 95 9
 2011 AF
CDF ${{\mathit e}}{{\mathit \mu}}$
$> 205$ 95 9
 2011 AF
CDF ${{\mathit e}}{{\mathit e}}$
$> 145$ 95 10
 2008 V
D0 ${{\mathit \mu}}{{\mathit \mu}}$
11
 2006 A
H1 single ${{\mathit H}^{\pm\pm}}$
$> 109$ 95 12
 2005 L
CDF stable
$>98.2$ 95 13
 2004 E
D0 ${{\mathit \mu}}{{\mathit \mu}}$
14
 2003 Q
OPAL $\mathit E_{{\mathrm {cm}}}{}\leq{}$209 GeV, single ${{\mathit H}^{\pm\pm}}$
15
 1997
SPEC muonium conversion
$>45.6$ 95 16
 1992 M
OPAL
$>25.5$ 95 17
 1992 M
OPAL
$\text{none 7.3 - 34.3}$ 95 18
 1990
MRK2
1  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.
2  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.
3  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.
4  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 $\mathit g_{ {{\mathit \ell}} {{\mathit \ell}^{\,'}} }{ {}\gtrsim{} }$ $10^{-7}$.
5  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 $\mathit g$( ${{\mathit H}}{{\mathit \ell}}{{\mathit \ell}}$ )${ {}\gtrsim{} }10^{-7}$.
6  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.
7  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.
8  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.
9  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.
10  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.
11  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.
12  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.
13  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 $\mathit g_{ {{\mathit \mu}} {{\mathit \mu}} }{ {}\gtrsim{} }$ $10^{-7}$.
14  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).
15  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.
16  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.
17  ACTON 1992M from $\Delta \Gamma _{{{\mathit Z}}}<$40 MeV.
18  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:
JHEP 1503 041 Search for Anomalous Production of Prompt Same-Sign Lepton Pairs and Pair-Produced Doubly Charged Higgs Bosons with $\sqrt {s }$ = 8 TeV ${{\mathit p}}{{\mathit p}}$ Collisions using the ATLAS Detector
JHEP 1508 138 Search for New Phenomena in Events with Three or More Charged Leptons in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
EPJ C72 2244 Search for Doubly Charged Higgs Bosons in Like-Sign Dilepton Final States at $\sqrt {s }$ = 7 TeV with the ATLAS Detector
PR D85 032004 Search for Anomalous Production of Prompt Like-Sign Muon Pairs and Constraints on Physics beyond the Standard Model with the ATLAS Detector
 ABAZOV 2012A
PRL 108 021801 Search for Doubly Charged Higgs Boson Pair Production in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
 AALTONEN 2011AF
PRL 107 181801 Search for New Physics in High $p_T$ Like-Sign Dilepton Events at CDF II
 ABAZOV 2008V
PRL 101 071803 Search for Pair Production of Doubly-Charged Higgs Bosons in the ${{\mathit H}^{++}}$ ${{\mathit H}^{--}}$ $\rightarrow$ ${{\mathit \mu}^{+}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}{{\mathit \mu}^{-}}$ Final State at ${D0}$
 AKTAS 2006A
PL B638 432 Search for Doubly-Charged Higgs Boson Production at HERA
 ACOSTA 2005L
PRL 95 071801 Search for Long-Lived Doubly Charged Higgs Bosons in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
 ABAZOV 2004E
PRL 93 141801 Search for Doubly Charged Higgs Boson Pair Production in the Decay to ${{\mathit \mu}^{+}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}{{\mathit \mu}^{-}}$ in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
 ABBIENDI 2003Q
PL B577 93 Search for the Single Production of Doubly Charged Higgs Bosons and Constraints on their Couplings from Bhabha Scattering
 ABDALLAH 2003
PL B552 127 Search for Doubly Charged Higgs Bosons at LEP2
 ACHARD 2003F
PL B576 18 Search for Doubly Charged Higgs Bosons at LEP
 ABBIENDI 2002C
PL B526 221 Search for Doubly Charged Higgs Bosons with the OPAL Detector at LEP
 GORDEEV 1997
PAN 60 1164 New Method of Investigating of the Muonium-to-Antimuonium Conversion
 ACTON 1992M
PL B295 347 A Search for Doubly Charged Higgs Production in ${{\mathit Z}^{0}}$ Decays
 SWARTZ 1990
PRL 64 2877 A Search for Doubly Charged Higgs Scalars in ${{\mathit Z}^{0}}$ Decays