No Arabic abstract
Recent evidence from the LHC for the Higgs boson with mass between 142 GeV < m_h < 147GeV points to PeV-scale Split Supersymmetry. This article explores the consequences of a Higgs mass in this range and possible discovery modes for Split Susy. Moderate lifetime gluinos, with decay lengths in the 25 microns to 10 years range, are its imminent smoking gun signature. The 7 TeV LHC will be sensitive to the moderately lived gluinos and trilepton signatures from direct electroweakino production. Moreover, the dark matter abundance may be obtained from annihilation through an s-channel Higgs resonance, with the LSP almost purely bino and mass m_chi = 70 GeV. The Higgs resonance region of Split Susy has visible signatures in dark matter direct and indirect detection and electric dipole moment experiments. If the anomalies go away, the majority of Split Susy parameter space will be excluded.
We examine the top squark (stop) and gluino reach of the proposed 33 TeV energy upgrade of the Large Hadron Collider (LHC33) in the Minimal Supersymmetric Standard Model (MSSM) with light higgsinos and relatively heavy electroweak gauginos. In our analysis, we assume that stops decay to higgsinos via ${tilde t}_1 to t {tilde{Z}}_1$, $tilde{t}_1 to ttilde{Z}_2$ and $tilde{t}$$_1 to btilde{W}_1$ with branching fractions in the ratio 1:1:2 (expected if the decay occurs dominantly via the superpotential Yukawa coupling) while gluinos decay via $tilde{g}to ttilde{t}_1$ or via three-body decays to third generation quarks plus higgsinos. These decay patterns are motivated by models of natural supersymmetry where higgsinos are expected to be close in mass to $m_Z$, but gluinos may be as heavy as $5 - 6$ TeV and stops may have masses up to $sim 3 $ TeV. We devise cuts to optimize the signals from stop and gluino pair production at LHC33. We find that experiments at LHC33 should be able to discover stops with $> 5sigma$ significance if $m_{tilde{t}_1} < 2.3 (2.8) [3.2]$ TeV for an integrated luminosity of 0.3 (1)[3] ab$^{-1}$. The corresponding reach for gluinos extends to 5 (5.5) [6] TeV. These results imply that experiments at LHC33 should be able to discover at least one of the stop or gluino pair signals even with an integrated luminosity of 0.3 ab$^{-1}$ for natural SUSY models with no worse than 3% electroweak fine-tuning, and quite likely both gluinos and stops for an integrated luminosity of 3 ab$^{-1}$.
We show that color-breaking vacua may develop at high temperature in the Mini-Split SUSY scenario. This can lead to a nontrivial cosmological history of the universe, including strong first order phase transitions and domain wall production. Given the typical PeV energy scale associated with Mini-Split SUSY models, a stochastic gravitational wave background at frequencies around 100 Hz is expected. We study the potential for detection of such a signal in future gravitational wave experiments.
In this work we consider the HL-LHC discovery potential in the 3 inverse ab data set for gluinos in the gluino-weakino associated production channel. We propose a search in the jets plus missing energy channel which exploits kinematic edge features in the reconstructed transverse mass of the gluino. We find that for squark masses in the 2 TeV range we have 5 sigma discovery potential for gluino masses in the range of 2.4 to 3 TeV, competitive with the projections for discovery potential in the gluino pair production channel.
The searches for heavy Higgs bosons and supersymmetric (SUSY) particles at the LHC have left the minimal supersymmetric standard model (MSSM) with an unusual spectrum of SUSY particles, namely, all squarks are beyond a few TeV while the Higgs bosons other than the one observed at 125 GeV could be relatively light. In light of this, we study a scenario characterized by two scales: the SUSY breaking scale or the squark-mass scale $(M_S)$ and the heavy Higgs-boson mass scale $(M_A)$.We perform a survey of the MSSM parameter space with $M_S < 10^{10}$ GeV and $M_A < 10^4$ GeV such that the lightest Higgs boson mass is within the range of the observed Higgs boson as well as satisfying a number of constraints. The set of constraints include the invisible decay width of the $Z$ boson and that of the Higgs boson, the chargino-mass limit, dark matter relic abundance from Planck, the spin-independent cross section of direct detection by LUX, and gamma-ray flux from dwarf spheroidal galaxies and gamma-ray line constraints measured by Fermi LAT. Survived regions of parameter space feature the dark matter with correct relic abundance, which is achieved through either coannihilation with charginos, $A/H$ funnels, or both. We show that future measurements, e.g., XENON1T and LZ, of spin-independent cross sections can further squeeze the parameter space.
In supersymmetric models, a correlation exists between the structure of the Higgs sector quartic potential and the coupling of the lightest CP-even Higgs to fermions and gauge bosons. We exploit this connection to relate the observed value of the Higgs mass ~ 125 GeV to the magnitude of its couplings. We analyze different scenarios ranging from the MSSM with heavy stops to more natural models with additional non-decoupling D-term/F-term contributions. A comparison with the most recent LHC data, allows to extract bounds on the heavy Higgs boson masses, competitive with bounds from direct searches.