Peisi Huang

Radiative natural supersymmetry with a 125 GeV Higgs boson.

It has been argued that requiring low electroweak fine-tuning (EWFT) along with a (partial) decoupling solution to the supersymmetry (SUSY) flavor and CP problems leads to a sparticle mass spectra characterized by light Higgsinos at 100-300 GeV, sub-TeV third generation scalars, gluinos at a few TeV, and multi-TeV first or second generation scalars (natural SUSY). We show that by starting with multi-TeV first or second and third generation scalars and trilinear soft breaking terms, the natural SUSY spectrum can be generated radiatively via renormalization group running effects. Using the complete 1-loop effective potential to calculate EWFT, significantly heavier third generation squarks can be allowed even with low EWFT. The large negative trilinear term and heavier top squarks allow for a light Higgs scalar in the ~125 GeV regime.

Radiative natural supersymmetry: Reconciling electroweak fine-tuning and the Higgs boson mass

Models of natural supersymmetry seek to solve the little hierarchy problem by positing a spectrum of light higgsinos m_0 leads to automatic cancellations during renormalization group (RG) running, and to radiatively-induced low fine-tuning at the electroweak scale. Coupled with large mixing in the top squark sector, RNS allows for fine-tuning at the 3-10% level with TeV-scale top squarks and a 125 GeV light Higgs scalar h. The model allows for at least a partial solution to the SUSY flavor, CP and gravitino problems since first/second generation scalars (and the gravitino) may exist in the 10-30 TeV regime. We outline some possible signatures for RNS at the LHC and at a linear e^+e^- collider. If the strong CP problem is solved by the Peccei-Quinn mechanism, then RNS naturally accommodates mixed axion-higgsino cold dark matter, where the light higgsino-like WIMPS - which in this case make up only a fraction of the measured relic abundance - should be detectable at upcoming WIMP detectors.

Same-Sign Diboson Signature from Supersymmetry Models with Light Higgsinos at the LHC

In supersymmetric models with light Higgsinos (which are motivated by electroweak naturalness arguments), the direct production of Higgsino pairs may be difficult to search for at the LHC due to the low visible energy release from their decays. However, the wino pair production reaction W2(±)Z4→(W(±)Z1,2)+(W(±)W1(∓)) also occurs at substantial rates and leads to final states including equally opposite-sign and same-sign diboson production. We propose a novel search channel for LHC14 based on the same-sign diboson plus missing ET final state which contains only modest jet activity. Assuming gaugino mass unification, and an integrated luminosity ≳100  fb(-1), this search channel provides a reach for supersymmetry well beyond that from usual gluino pair production.

Probing the electroweak phase transition with Higgs factories and gravitational waves

After the discovery of the Higgs boson, understanding the nature of electroweak symmetry breaking and the associated electroweak phase transition has become the most pressing question in particle physics. Answering this question is a priority for experimental studies. Data from the LHC and future lepton collider-based Higgs factories may uncover new physics coupled to the Higgs boson, which can induce the electroweak phase transition to become first order. Such a phase transition generates a stochastic background of gravitational waves, which could potentially be detected by a space-based gravitational wave interferometer. In this paper, we survey a few classes of models in which the electroweak phase transition is strongly first order. We identify the observables that would provide evidence of these models at the LHC and next-generation lepton colliders, and we assess whether the corresponding gravitational wave signal could be detected by eLISA. We find that most of the models with first-order electroweak phase transition can be covered by the precise measurements of Higgs couplings at the proposed Higgs factories. We also map out the model space that can be probed with gravitational wave detection by eLISA.

Radiatively-driven natural supersymmetry at the LHC

A bstractRadiatively-driven natural supersymmetry (RNS) potentially reconciles the Z and Higgs boson masses close to ~100 GeV with gluinos and squarks lying beyond the TeV scale. Requiring no large cancellations at the electroweak scale in constructing MZ = 91.2 GeV while maintaining a light Higgs scalar with mh ≃ 125 GeV implies a sparticle mass spectrum including light higgsinos with mass ~100 − 300 GeV, electroweak gauginos in the 300 − 1200 GeV range, gluinos at 1 − 4 TeV and top/bottom squarks in the 1-4 TeV range (probably beyond LHC reach), while first/second generation matter scalars can exist in the 5-30 TeV range (far beyond LHC reach). We investigate several characteristic signals for RNS at LHC14. Gluino pair production yields a reach up to

Natural SUSY with a bino- or wino-like LSP

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Flavor-Tuned 125 GeV SUSY Higgs Boson at the LHC : MSSM and NATURAL SUSY TESTS

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Distinguishing LSP archetypes via gluino pair production at LHC13

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Higgs boson finder and mass estimator: The Higgs boson to W W to leptons decay channel at the LHC

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Erratum to: Radiatively-driven natural supersymmetry at the LHC

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