Light Higgs bosons in phenomenological NMSSM

We consider scenarios in the next-to-minimal supersymmetric model (NMSSM) where the CP-odd and charged Higgs bosons are very light. As we demonstrate, these can be obtained as simple deformations of existing phenomenological MSSM benchmarks scenarios with parameters defined at the weak scale. This offers a direct and meaningful comparison to the MSSM case. Applying a wide set of up-to-date constraints from both high-energy collider and flavor physics, the Higgs boson masses and couplings are studied in viable parts of parameter space. The LHC phenomenology of the light Higgs scenario for neutral and charged Higgs boson searches is discussed.     

Higgsino asymmetry and direct-detection constraints of light dark matter in the NMSSM with non-universal Higgs masses

In this study,we analyze the direct-detection constraints of light dark matter in the next-to minimal supersymmetric standard model(NMSSM)with non-universal Higgs masses(NUHM);we specially focus on the correlation between higgsino asymmetry and spin-dependent(SD)cross section.We draw the following conclusions.(i)The SD cross section is proportional to the square of higgsino asymmetry in dark matter X₁⁰in the NMSSM-NUHM,and hence,it is small for highly singlino-dominated dark matter,(ii)The higgsino-mass parameter μeff is smaller than approximately 335 GeV in the NMSSM-NUHM due to the current muon g-2 constraint,but our scenario with light dark matter can still be alive under current constraints including the direct detection of dark matter in the spindependent channel.(iii)With a sizeable higgsino component in the light dark matter,the higgsino asymmetry and SD cross section can also be sizeable,but dark matter relic density is always small;thus,it can escape the direct detections.(iv)Light dark matter in the h₂-and Z-funnel annihilation channels with sufficient relic density can be covered by future LUX-ZEPLIN(LZ)7-ton in SD detections.(v)The spin-independent(SI)cross section is dominated by h₁-and h₂-exchanging channels,which can even cancel each other in some samples,leaving an SI cross section smaller by a few orders of magnitude than that of one individual channel.     

Mini little Higgs and dark matter

We construct a little Higgs model with the most minimal extension of the standard model gauge group by an extra U(1)$U(1)$ gauge symmetry. For specific charge assignments of scalars, an approximate U(3)$U(3)$ global symmetry appears in the cutoff-squared scalar mass terms generated from gauge bosons at one-loop level. Hence, the Higgs boson, identified as a pseudo-Goldstone boson of the broken global symmetry, has its mass radiatively protected up to scales of 5–10 TeV. In this model, a Z₂$Z_2$ symmetry, ensuring the two U(1)$U(1)$ gauge groups to be identical, also makes the extra massive neutral gauge boson stable and a viable dark matter candidate with a promising prospect of direct detection.     

Vector Higgs portal dark matter and the invisible Higgs

The Higgs sector of the Standard Model offers a unique probe of the hidden sector. In this work, we explore the possibility of renormalizable Higgs couplings to the hidden sector vector fields which can constitute dark matter (DM). Abelian gauge sectors with minimal field content, necessary to render the gauge fields massive, have a natural Z₂ parity. This symmetry ensures stability of the vector fields making them viable dark matter candidates, while evading the usual electroweak constraints. We illustrate this idea with the Stückelberg and Higgs mechanisms. Vector DM is consistent with the WMAP, XENON100, and LHC constraints, while it can affect significantly the invisible Higgs decay. Due to the enhanced branching ratio for the Higgs decay into the longitudinal components of the vector field, the vector Higgs portal provides an efficient way to hide the Higgs at the LHC. This could be the reason why the latest combined ATLAS/CMS data did not bring evidence for the existence of the Higgs boson.     

NMSSM with gravitino dark matter to be tested at LHC

We present a solution to the gravitino problem, which arises in the NMSSM, allowing for sparticle spectra from ordinary gravity-mediated supersymmetry breaking with weak-scale gravitino dark matter. The coupling, which links the singlet to the MSSM sector, enhances the tree-level Higgs mass, providing an attractive explanation why the observed Higgs boson is so heavy. The same coupling induces very efficient pair-annihilation processes of the neutralino NLSP. Its relic abundance can be sufficiently suppressed to satisfy the strong constraints on late decaying relics from primordial nucleosynthesis – even for very long neutralino lifetimes. The striking prediction of this scenario is the detection of a pseudoscalar Higgs boson in the search for top–top resonances at LHC-14, rendering it completely testable.     

Neutralino dark matter in light Higgs boson scenario

Phenomenology of neutralino dark matter in the minimal supersymmetric model is discussed for a scenario where the lightest Higgs boson mass is lighter than 114.4 GeV$114.4\text{GeV}$. We show that the scenario is consistent not only with many collider experiments but also with the observed relic abundance of dark matter. The allowed region may be probed by experiments of Bs→μ⁺μ⁻$B_s\to {\mu }^{+}{\mu }^{-}$ in near future. The scenario predicts a large scattering cross section between the dark matter and ordinary matter and thus it may be tested in present direct detection experiments of dark matter.     

Light Higgs boson in the NMSSM confronted with the CMS di-photon and di-tau excesses

In 2018, the CMS collaboration reported a di-photon excess at approximately 95.3 GeV with a local significance of 2.8 σ. Interestingly, the CMS collaboration also recently reported a di-tau excess at 95-100 GeV with a local significance of 2.6-3.1 σ. In addition, a bb excess at 98 GeV with a local significance of 2.3 σ was reported from LEP data approximately twenty years ago. In this study, we addressed the interpretation of these excesses together with a light Higgs boson in the next-to-minima...     

Classification of dark pion multiplets as dark matter candidates and collider phenomenology

In this work we propose to use leading singularities to obtain the classical pieces of amplitudes of two massive particles whose only interaction is gravitational. Leading singularities are generalizations of unitarity cuts. At one-loop we find that leading singularities obtained by multiple discontinuities in the t-channel contain all the classical information. As the main example, we show how to obtain a compact formula for the fully relativistic classical one-loop contribution to the scattering of two particles with different masses. The non-relativistic limit of the leading singularity agrees with known results in the post-Newtonian expansion. We also compute a variety of higher loop leading singularities including some all-loop families and study some of their properties.     

Significant gamma lines from inert Higgs dark matter

One way to unambiguously confirm the existence of particle dark matter and determine its mass would be to detect its annihilation into monochromatic gamma-rays in upcoming telescopes. One of the most minimal models for dark matter is the inert doublet model, obtained by adding another Higgs doublet with no direct coupling to fermions. For a mass between 40 and 80 GeV, the lightest of the new inert Higgs particles can give the correct cosmic abundance of cold dark matter in agreement with current observations. We show that for this scalar dark matter candidate, the annihilation signal of monochromatic gammagamma and Zgamma final states would be exceptionally strong. The energy range and rates for these gamma-ray line signals make them ideal to search for with the soon upcoming GLAST satellite.     

WIMP dark matter in gauge-mediated SUSY breaking models and its phenomenology

We propose an extended version of the gauge-mediated SUSY breaking models where extra SUL₍₂₎$\mathit{SU}{(2)}_L$ doublets and singlet field are introduced. These fields are assumed to be parity-odd under an additional matter parity. In this model, the lightest parity-odd particle among them would be dark matter in the Universe. In this Letter, we discuss direct detection of the dark matter and the collider signatures of the model.     

The constrained NMSSM and Higgs near 125 GeV

We assess the extent to which various constrained versions of the NMSSM are able to describe the recent hints of a Higgs signal at the LHC corresponding to a Higgs mass in the range 123–128 GeV.     

Inverse seesaw in NMSSM and 126 GeV Higgs boson

We consider extensions of the next-to-minimal supersymmetric model (NMSSM) in which the observed neutrino masses are generated through a TeV scale inverse seesaw mechanism. The new particles associated with this mechanism can have sizable couplings to the Higgs field which can yield a large contribution to the mass of the lightest CP-even Higgs boson. With this new contribution, a 126 GeV Higgs is possible along with order of 200 GeV masses for the stop quarks for a broad range of tan β. The Higgs production and decay in the diphoton channel can be enhanced due to this new contribution. It is also possible to solve the little hierarchy problem in this model without invoking a maximal value for the NMSSM trilinear coupling and without severe restrictions on the value of tan β.     

Characterizing Higgs portal dark matter models at the ILC

We study the dark matter (DM) discovery prospect and its spin discrimination in the theoretical framework of gauge invariant and renormalizable Higgs portal DM models at the ILC with \(\sqrt{s} = 500\) GeV. In such models, the DM pair is produced in association with a Z boson. In the case of the singlet scalar DM, the mediator is just the SM Higgs boson, whereas for the fermion or vector DM there is an additional singlet scalar mediator that mixes with the SM Higgs boson, which produces significant observable differences. After careful investigation of the signal and backgrounds both at parton level and at detector level, we find the signal with hadronically decaying Z boson provides a better search sensitivity than the signal with leptonically decaying Z boson. Taking the fermion DM model as a benchmark scenario, when the DM-mediator coupling \(g_\chi \) is relatively small, the DM signals are discoverable only for benchmark points with relatively light scalar mediator \(H_2\). The spin discriminating from scalar DM is always promising, while it is difficult to discriminate from vector DM. As for \(g_\chi \) approaching the perturbative limit, benchmark points with the mediator \(H_2\) in the full mass region of interest are discoverable. The spin discriminating aspects from both the scalar and the fermion DM are quite promising.     

Light neutralino dark matter in the pMSSM

We present an investigation of the dependence of searches for boosted Higgs bosons using jet substructure on the perturbative and non-perturbative parameters of the Herwig++ Monte Carlo event generator. Values are presented for a new tune of the parameters of the event generator, together with the an estimate of the uncertainties based on varying the parameters around the best-fit values.