Multi-photon signatures at the Fermilab Tevatron

Fermiophobic Higgs bosons (h_f) exhibiting large branching ratios for decay to two photons can arise in models with two or more scalar doublets and/or triplets. In such models the conventional production mechanisms at hadron colliders, which rely on the h_fVV coupling (V=W,Z), may be rendered ineffective due to severe mixing angle suppression. In this scenario, double h_f production may proceed via the complementary mechanism qq’→H^±h_f with subsequent decay H^±→h_fW^*, leading to events with up to four photons. We perform a simulation of the detection prospects of h_f in the multi-photon (>3) channel at the Fermilab Tevatron and show that a sizeable region of the (m_H±,m_hf) parameter space can be probed during Run II.     

Detecting an invisible Higgs boson at Fermilab Tevatron and CERN LHC

In this paper, we study the observability of an invisible Higgs boson at Fermilab Tevatron and CERN LHC through the production channel qq̄→ZH→ℓ⁺ℓ^-+P/_T, where/P_T is reconstructed from the ℓ⁺ℓ^- with ℓ=e or μ. A new strategy is proposed to eliminate the largest irreducible background, namely qq̄→Z(→ℓ⁺ℓ^-)Z(→νν̄). This strategy utilizes the precise measurements of qq̄→Z(→ℓ⁺ℓ^-)Z(→ℓ⁺ℓ^-). For m_H=120 GeV and with luminosity 30 fb^-1 at Tevatron, a 5σ observation of the invisible Higgs boson is possible. For m_H=114∼140 GeV with only 10 fb^-1 luminosity at LHC, a discovery signal over 5σ can be achieved. PACS 14.80.Cp     

Diffractive Higgs boson production at the Fermilab Tevatron and the CERN Large Hadron Collider

Improved possibilities to find the Higgs boson in diffractive events, having less hadronic activity, depend on whether the cross section is large enough. Based on the soft color interaction models that successfully describe diffractive hard scattering at DESY HERA and the Fermilab Tevatron, we find that only a few diffractive Higgs events may be produced at the Tevatron, but we predict a substantial rate at the CERN Large Hadron Collider.     

Jet signatures of scalar diquarks from superstrings at CERN and Fermilab

We calculate the contribution to the four-jet yield in p̄p collisions of two scalar, colour triplet, hypercharge $\text{±}\text{1}\text{3}$ pure diquarks resulting from E₆ compactification in superstring theories. Measured cross sections at the CERN Collider are sensitive to this contribution for masses up to ∼40 GeV. Fermilab-Tevatron data with similar cuts will push this bound up to ∼70 GeV.