--- title: 'WINO+: Wino-Centered Supersymmetric Dark Matter' url: https://www.emergentmind.com/topics/wino type: topic --- # WINO+: Wino-Centered Supersymmetric Dark Matter In the cited literature, “WINO+” is used for a family of wino-centered supersymmetric dark matter constructions rather than for a single uniquely fixed model. Depending on context, the term refers to a neutral wino lightest supersymmetric particle (LSP), the positively charged component of the wino multiplet, a bino LSP whose relic history is controlled by a nearby wino, or a wino sector augmented by an axion supermultiplet or by heavy-higgsino-induced long lifetimes. This suggests that the unifying content of WINO+ is not one benchmark spectrum but the recurrent role of the SU(2)\(_L\) wino in relic density, indirect detection, direct detection, and collider phenomenology [1504.05554] [1311.2162] [1502.07198] [1506.08799]. ## 1. Meanings of the label in the literature The usage of “WINO+” is explicitly context-dependent in the cited papers. In some works it denotes the wino itself, especially the charged state \(\tilde W^+\); in others it denotes a “wino plus” construction in which the wino assists another dark matter sector. | Usage | Definition | Representative papers | |---|---|---| | Pure wino dark matter | Neutral wino LSP, often in anomaly mediation or pure gravity mediation | [1504.05554], [1401.6212] | | Charged wino | Positively charged component of the wino multiplet | [2210.16035], [2312.08087] | | Wino-assisted bino dark matter | Bino LSP with a slightly heavier wino NLSP | [1311.2162] | | Wino plus PQ sector | Mixed axion–wino dark matter | [1502.07198] | | Long-lived bino–wino sector | Heavier bino or wino becomes long-lived for heavy higgsinos | [1506.08799] | A closely related collider usage appears in studies of a wino-like LSP at the LHC, where the standard trilepton analysis is re-optimized for a wino-dominated neutralino rather than the bino-like LSP assumed in conventional simplified models [1710.05536]. The term therefore functions as a label for wino-centered phenomenology across several adjacent model classes. ## 2. Electroweak triplet structure and the canonical pure-wino picture In supersymmetric extensions of the Standard Model, the winos form an \(SU(2)_L\) triplet, \[ \tilde W = (\tilde W^+, \tilde W^0, \tilde W^-)\,. \] In anomaly-mediated and pure-gravity-mediation-like settings with heavy Higgsinos, the lightest superparticle is often an almost pure neutral wino \(\tilde W^0\), which is stable if \(R\)-parity is conserved and thus a dark matter candidate [1504.05554]. A defining feature of the pure-wino spectrum is the small charged–neutral mass splitting. In the high-scale SUSY and co-annihilation literature this splitting is quoted as \[ \Delta m_{\tilde w} = m_{\tilde w^\pm}-m_{\tilde w^0} \simeq 150\text{–}170~\text{MeV}, \] while the AMS-02 wino study describes it more broadly as \(O(100)\,\text{MeV}\) [1311.2162] [1504.05554]. This small splitting implies the dominant decay \[ \tilde W^\pm \to \tilde W^0 + \pi^\pm, \] and produces the disappearing-track signature central to collider searches. The 2015 AMS-02 study quoted an ATLAS bound \(M_{\tilde w}\gtrsim 270\,\text{GeV}\) from 8 TeV data with \(20~\text{fb}^{-1}\), together with prospects of \(\sim 500\) GeV at 14 TeV with \(100~\text{fb}^{-1}\) [1504.05554]. Later disappearing-track interpretations used an ATLAS exclusion around \(m_\chi \approx 660\,\text{GeV}\) at 13 TeV with \(136~\text{fb}^{-1}\) [2210.16035]. The thermal relic point lies in the multi-TeV regime. One line of work quotes the thermal wino mass as \[ M_{\tilde w}\simeq 3~\text{TeV}, \] once Sommerfeld enhancement is included in freeze-out [1504.05554]. A later direct-detection study summarizes the thermal window more broadly as \(m_\chi\sim 2.7\text{–}3.1~\text{TeV}\) [2305.13837]. This multi-TeV mass scale is the benchmark against which most indirect-detection limits and next-generation direct-detection projections are formulated. ## 3. Annihilation dynamics, Sommerfeld enhancement, and indirect searches For a pure neutral wino, the dominant present-day annihilation channel is \[ \tilde W^0 \tilde W^0 \to W^+W^-. \] Because the wino is an electroweak triplet, long-range \(SU(2)_L\) interactions generate a non-perturbative Sommerfeld enhancement at halo velocities \(v\sim 10^{-3}\). The AMS-02 analysis summarizes the resulting annihilation rate as \[ \langle \sigma v \rangle_{\tilde W^0\tilde W^0\to W^+W^-}\sim 10^{-24}-10^{-25}\,\text{cm}^3\,\text{s}^{-1} \] for TeV-scale winos [1504.05554]. The 2014 indirect-detection case study likewise emphasized that near the resonance region the present-day annihilation rate can reach \(\mathcal{O}(10^{-24}\text{–}10^{-23})\,\text{cm}^3\text{s}^{-1}\), with a pronounced Sommerfeld resonance around \(m_\chi \approx 2.4\,\text{TeV}\) [1401.6212]. This large annihilation rate makes antiprotons and gamma rays the leading probes. In the AMS-02 antiproton analysis, the preferred wino masses were \(2.5\,\text{TeV}\), \(2.9\,\text{TeV}\), and \(3.2\,\text{TeV}\) for the MIN, MED, and MAX propagation models, respectively, and the paper emphasized that the thermal \(\sim 3\) TeV wino gave a particularly good fit to the 2015 \(\bar p/p\) spectrum. It also predicted that the ratio should decrease quickly at the energy several hundreds of GeV if this explanation is correct [1504.05554]. At the same time, multichannel indirect-detection studies found strong exclusions under standard halo assumptions. One such analysis concluded that a pure wino constituting all of dark matter is excluded below \(\sim 800\,\text{GeV}\) from antiprotons and between \(1.8\) and \(3.5\,\text{TeV}\) from the absence of a gamma-ray line feature toward the Galactic Center [1401.6212]. A more refined effective-field-theory treatment of the semi-inclusive \(\gamma+X\) channel later showed that LL′ corrections reduce the \(3\) TeV wino rate by \(\sim 30\%\) relative to LL, but still leave the thermal wino excluded by an order of magnitude in a HESS-like analysis [1510.02470]. The inferred status depends sensitively on the Galactic halo profile. A dedicated gamma-line study found that for \(M_\chi \simeq 3\,\text{TeV}\) and \(f_{\tilde W}=1\), the predicted \(\gamma+X\) rate exceeds the HESS bound by more than an order of magnitude for an NFW halo, while viability can be restored by a cutoff-NFW core radius \(r_c \approx 1\text{–}1.5~\text{kpc}\) or a Burkert core radius \(r_c \approx 4\text{–}4.5~\text{kpc}\) [1412.8698]. The resulting literature therefore presents a persistent tension: the thermal wino is simultaneously a sharply predictive relic candidate and a target of strong, profile-dependent indirect-detection exclusions. ## 4. Direct detection and loop-induced nucleon scattering Pure-wino direct detection is loop-dominated when higgsinos and other superpartners are heavy. An early complete calculation in anomaly mediation found that the spin-independent wino–proton cross section lies in the range \[ 10^{-(46\text{–}48)}~\text{cm}^2, \] is almost independent of the wino mass, and is highly sensitive to the Higgs boson mass because of an accidental cancellation among scalar and twist-2 contributions [1004.4090]. The QCD completion of this program, carried out to next-to-leading order in \(\alpha_s\), substantially sharpened the prediction. In the large-wino-mass limit it obtained \[ \sigma_{\text{SI}}^p = 2.3~{}^{+0.2}_{-0.3}~{}^{+0.5}_{-0.4}\times 10^{-47}~ \text{cm}^2, \] with the first error from perturbative calculation and the second from input parameters, and found the NLO result to be larger than the leading-order one by about \(70\%\) [1504.00915]. That analysis emphasized that the resulting cross section lies well above the neutrino background. More recent work revisited the electroweak loop sector in realistic AMSB and pure-gravity-mediation spectra. It found that one-loop electroweak corrections interfere constructively with the tree-level contribution for AMSB models with negative Higgsino mixing, \(\mu<0\), and in PGM-like models for both signs of \(\mu\), thereby lifting the cross section out of the neutrino fog and into a range potentially detectable in next-generation direct searches [2305.13837]. The same paper also showed that AMSB with \(\mu>0\) can instead exhibit destructive interference and even a near-cancellation. The direct-detection literature thus moved from a purely loop-suppressed “invisible wino” picture to one in which QCD matching, electroweak interference, and the sign of \(\mu\) all materially affect observability. ## 5. Wino-assisted relic histories and mixed dark sectors Several papers use WINO+ to denote scenarios in which the wino is indispensable even though it is not the dominant relic. In the bino–wino co-annihilation scenario, the LSP is bino-like, the wino is the NLSP, and the relevant mass splitting satisfies \[ \Delta m_{\tilde b}\equiv m_{\tilde w}-m_{\tilde b}\lesssim 30~\text{GeV}. \] Because bino–wino mixing is tiny, \[ \theta_{BW}\sim \mathcal{O}\!\left(\frac{m_Z^2}{\mu\,|m_{\tilde w}-m_{\tilde b}|}\right)\ll 1, \] the LSP remains at least \(99\%\) bino-like, while wino annihilation channels dominate the effective freeze-out cross section [1311.2162]. When gravitino decay adds a nonthermal component, the final state is mixed cold+warm bino dark matter. In the allowed parameter space the warm fraction satisfies \[ r_{\rm warm}\gtrsim \mathcal{O}(1\%), \] with free-streaming scale \[ k_{\rm fs}\sim 10^3\text{–}10^4~\text{Mpc}^{-1}, \] so that the most sensitive probe is not current galaxy-scale structure but future 21 cm observations at \(z\sim 30\text{–}200\) [1311.2162]. A different use of WINO+ appears in mixed axion–wino dark matter. There the wino-like LSP is underabundant thermally, \[ \Omega_{\tilde{W}}^{\rm TP} h^2 \sim 0.12\left(\frac{M_2}{2.5\ \text{TeV}}\right)^2, \] so a \(200\) GeV wino gives \(\sim 0.0008\), and the CSB benchmark yields \(\Omega_{\tilde{\chi}^0_1}^{\rm std} h^2 \simeq 0.002\) [1502.07198]. Axino and saxion decays then non-thermally increase the wino abundance, while axion misalignment supplies the remaining relic density. The allowed Peccei–Quinn scale depends strongly on KSVZ versus DFSZ and on whether \(s\to aa,\tilde a\tilde a\) is switched on, but no model in that analysis allowed \(f_a\sim 10^{16}\,\text{GeV}\) for the heavy saxion masses considered [1502.07198]. These constructions suggest a broader meaning of WINO+: a wino may function not only as the dark matter particle itself but also as the sector that fixes relic abundance, nonthermal history, or small-scale structure. ## 6. Long-lived electroweakinos, charged-wino precision, and collider searches Heavy higgsinos can seclude the bino and wino sectors from each other. In that regime the bino–wino mixing angle scales as \[ \theta_{BW}\sim \frac{m_Z^2}{\mu(M_2-M_1)}\sin 2\beta, \] and the heavier of bino and wino can become long-lived because the relevant couplings scale as \(m_Z/\mu\) or \((m_Z/\mu)^2\) [1506.08799]. The long-lived phenomenology is especially pronounced when the bino–wino mass splitting is below the electroweak-boson thresholds, forcing decays into three-body channels. For a wino NLSP with \(\Delta M< m_Z\), the paper gave the approximate neutral-wino lifetime \[ c\tau_{\tilde W^0} \simeq 1\,{\rm cm}\, \left( \frac{\mu}{10^2\,{\rm TeV}} \right)^2 \left( \frac{50\,{\rm GeV}}{\Delta M} \right)^5 \left( \frac{1}{\sin 2\beta} \right)^2, \] while for a charged wino with \(\Delta M100\) GeV and \[ 75~\text{GeV} < M_{\ell^+\ell^-} < 105~\text{GeV}. \] With this strategy, the combined significance from the two trilepton channels exceeded \(4\sigma\) for a wino-like DM mass around \(100\,\text{GeV}\) with an integrated luminosity as low as \(100~\text{fb}^{-1}\) at 14 TeV [1710.05536]. ## 7. Status, tensions, and future directions The cited literature consistently presents the thermal wino near \(3\) TeV as one of the most sharply predictive supersymmetric dark matter candidates. It is selected by thermal freeze-out including Sommerfeld enhancement, can fit the AMS-02 antiproton spectrum under some propagation assumptions, and has a loop-generated direct-detection cross section in the \(10^{-47}\,\text{cm}^2\) range [1504.05554] [1504.00915]. At the same time, it is under sustained pressure from indirect searches, especially Galactic-center gamma-ray lines and semi-inclusive \(\gamma+X\) analyses, unless the Milky Way halo is sufficiently cored [1412.8698] [1510.02470]. Several future tests recur across the papers. The AMS-02 antiproton interpretation predicts a rapid decrease in \(\bar p/p\) at several hundreds of GeV and emphasizes that improved B/C measurements will constrain propagation uncertainties [1504.05554]. Next-generation direct-detection searches are relevant because electroweak loop corrections can lift the wino signal out of the neutrino fog in AMSB with \(\mu<0\) and in PGM-like models [2305.13837]. Collider reach continues to depend on disappearing-track systematics and precise lifetime predictions [2210.16035]. In indirect detection, improved determinations of dwarf-spheroidal \(J\)-factors, Galactic halo coring, and endpoint-sensitive \(\gamma+X\) calculations remain central [1412.8698] [1510.02470]. A more specialized extension appears in electroweak WIMPonium. For SU(2) triplet dark matter, single-photon capture into bound states becomes possible for wino masses above \(5\) TeV and relative velocity \(v < O(10^{-2})\), but the capture rate is suppressed relative to direct annihilation and therefore gives only a small correction to the overall annihilation rate [1610.07617]. The soft photons from capture and subsequent bound-state transitions were proposed as possible probes of the dark matter quantum numbers, though the paper described them as rare for wino-like dark matter [1610.07617]. Taken together, these studies portray WINO+ as a technically mature but conceptually plural domain: pure thermal wino dark matter, wino-assisted relic scenarios, and long-lived electroweakino sectors all inherit the same electroweak-triplet dynamics, yet differ sharply in which observable—antiprotons, gamma rays, nucleon scattering, disappearing tracks, or small-scale structure—carries the decisive information. Source: https://www.emergentmind.com/topics/wino