A5075244093- Cosmology and Gravitation Theories
- Particle physics theoretical and experimental studies
- Black Holes and Theoretical Physics
- Dark Matter and Cosmic Phenomena
- Noncommutative and Quantum Gravity Theories
- Quantum Chromodynamics and Particle Interactions
- Computational Physics and Python Applications
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Pulsars and Gravitational Waves Research
- Relativity and Gravitational Theory
- Quantum Electrodynamics and Casimir Effect
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Astrophysics and Cosmic Phenomena
- Advanced Differential Geometry Research
- Galaxies: Formation, Evolution, Phenomena
- Geophysics and Gravity Measurements
- Astrophysical Phenomena and Observations
- Advanced Mathematical Theories and Applications
- Earth Systems and Cosmic Evolution
- Nonlinear Waves and Solitons
- Quantum chaos and dynamical systems
- Quantum and electron transport phenomena
- Orbital Angular Momentum in Optics
The University of Sydney
2014-2024
ARC Centre of Excellence for Particle Physics at the Terascale
2011-2019
The University of Melbourne
2007-2015
University of North Carolina at Chapel Hill
2005-2008
Georgian National Academy of Sciences
1994-2006
Helsinki Institute of Physics
2000-2006
University of Helsinki
2000-2006
If scale invariance is a classical symmetry then both the Planck and weak should emerge as quantum effects. We show that this can be realized in simple invariant theories with hidden sector. The weak/Planck hierarchy emerges (technically natural) limit which sector decouples from ordinary In limit, finite corrections to are consequently small, while quadratic divergences absent by virtue of invariance, so there no problem.
We investigate the properties of a stochastic gravitational wave background produced by first-order electroweak phase transition in regime extreme supercooling. study scenario whereby percolation temperature that signifies completion transition, $T_p$, can be as low few MeV (nucleosynthesis temperature), while most true vacuum bubbles are formed much earlier at nucleation temperature, $T_n\sim 50$ GeV. This implies spectrum is mainly collisions large and characterised amplitude peak...
We investigate a strategy to search for light, nearly degenerate higgsinos within the natural MSSM at LHC. demonstrate that higgsino mass range μ in 100−160 GeV, which is preferred by naturalness, can be probed 3σ significance through monojet 14 TeV HL-LHC with 3000 fb−1 luminosity. The proposed method also probe certain region parameter space lightest neutralino high purity, cannot reached planned direct detection experiments XENON-1 T(2017).
The violation of Baryon Number, $\mathcal{B}$, is an essential ingredient for the preferential creation matter over antimatter needed to account observed baryon asymmetry in universe. However, such a process has yet be experimentally observed. HIBEAM/NNBAR %experiment program proposed two-stage experiment at European Spallation Source (ESS) search number violation. will include high-sensitivity searches processes that violate by one or two units: free neutron-antineutron oscillation...
We define a theory of noncommutative general relativity for canonical spaces. find subclass coordinate transformations acting on spacetimes to be volume-preserving transformations. Local Lorentz invariance is treated as gauge with the spin connection field taken in so(3,1) enveloping algebra. The resulting appears extension unimodular gravitation. compute leading order correction action and derive equations motion weak gravitation field.
Scale invariance may be a classical symmetry which is broken radiatively. This provides simple way to stabilize the scale of electroweak breaking against radiative corrections. The simplest phenomenologically successful model this type involves addition one real scalar field standard model. In minimal Higgs can interpreted as pseudo-Goldstone boson invariance. We study possible origin neutrino mass in such models, both at tree-level and
We discuss a class of technically-natural UV extensions the Standard Model in which electroweak scale is shielded from large radiative corrections heavy physics due to an enhanced Poincare symmetry. Such sectors can be invoked provide solutions known shortcomings Model, such strong-CP problem, absence dark matter, and lack neutrino masses. relationship scale-invariant models.
The top and bottom seesaw model, which extends the in order to accommodate a 125 GeV Higgs boson, predicts vector-like top/bottom partners these can be bounded form several neutral charged singlet composite scalars by some new strong dynamics. In this letter, we use such scalar interpret 750 diphoton resonance. This is dominantly produced through gluon fusion process induced its decay both scalars. We show that scenario readily account for observed signal under current LHC constraints....
We argue that experiments with ultracold neutrons in the gravitational field of Earth disprove recent speculations on entropic origin gravitation.Received 27 September 2010DOI:https://doi.org/10.1103/PhysRevD.83.021502© 2011 American Physical Society
Scale invariance may be a classical symmetry which is broken radiatively. This provides simple way to stabilise the scale of electroweak breaking against radiative corrections. But for such theory fully realistic, it must actually incorporate hierarchy scales, including Planck and neutrino mass scales in addition scale. The dark matter sector physics responsible baryogenesis or not require new depending on scenario. We develop generic using hidden sectors construct technically-natural...
So far, the experiments at Large Hadron Collider (LHC) have shown no sign of new physics beyond Standard Model. Assuming Model is correct presently available energies, we can accurately extrapolate theory to higher energies in order verify its validity. Here report results high precision calculations which show that absolute stability Higgs vacuum state now excluded. Combining these with recent observation primordial gravitational waves by BICEP Collaboration, find would quickly decayed...
The gravitational wave signal GW150914, recently detected by LIGO and Virgo collaborations, is used to place a bound on the scale of quantum fuzziness noncommutative space-time. We show that leading correction phase waves produced binary system appears at second order post-Newtonian expansion. This proportional ${\mathrm{\ensuremath{\Lambda}}}^{2}\ensuremath{\equiv}|{\ensuremath{\theta}}^{0i}{|}^{2}/({l}_{P}{t}_{P}{)}^{2}$, where ${\ensuremath{\theta}}^{\ensuremath{\mu}\ensuremath{\nu}}$...
In this work, we calculate the leading order corrections to general relativity formulated on a canonical noncommutative spacetime. These appear in second of expansion theta. First can only gravity-matter interactions. Some implications are briefly discussed.
We show that Ho\ifmmode \check{r}\else \v{r}\fi{}ava's theory of gravitation with the global Hamiltonian constraint does not reproduce general relativity in infrared domain. There is one extra propagating degree freedom, besides those two associated massless graviton, which decouple.
We investigate indirect constraints on the top partner within minimal fermionic model. By performing a global fit of latest Higgs data, $B_s \to \mu^+\mu^-$ measurements and electroweak precision observables we find that with mass up to 830 GeV is excluded at $2\sigma$ level. Our bound much stronger than bounds obtained from direct searches LHC. Under current fine-tuning measure less 9% branching ratio $T tZ$ bounded between 14% 25%. also precise couplings 240 TLEP will constrain in multi-TeV region.
In this paper, we put constraints on anomalous $$ \mathcal{C}\mathcal{P} -violating top-Higgs couplings using the currently available Higgs data and explore prospect of measuring these at 240 GeV TLEP. We find that phase ξ is limited in range |ξ| <0.6π 95% C.L. may be further constrained to <0.07π Under consideration, investigate observability scalar (ξ =0), pseudoscalar =0.5π) mixed =0.25π) interactions through channel pp\to t\left(\to {\ell}^{+}{\nu}_{\ell }b\right)h\left(\to...
We propose a new class of natural inflation models based on hidden scale invariance. In very generic Wilsonian effective field theory with an arbitrary number scalar fields, which exhibits invariance via the dilaton, potential necessarily contains flat direction in classical limit. This is lifted by small quantum corrections and realised without need for unnatural fine-tuning. conformal limit, becomes linear inflaton field, yielding to specific predictions spectral index tensor-to-scalar...
We propose that the 750 GeV resonance, presumably observed in early LHC Run 2 data, could be a heavy composite axion results from condensation of hypothetical quark high-colour representation conventional QCD. The model, motivated by recently proposed solution to strong CP problem, is very economical and essentially defined properties additional - its colour charge, hypercharge mass. mass coupling two photons (via axial anomaly) can computed terms these parameters. predominantly produced via...
We explore the ability of current and future dark matter collider experiments in probing anomalous magnetic moment muon, $(g\ensuremath{-}2{)}_{\ensuremath{\mu}}$, within minimal supersymmetric standard model (MSSM). find that latest PandaX-II/LUX-2016 data give a strong constraint on parameter space accommodates $(g\ensuremath{-}2{)}_{\ensuremath{\mu}}$ $2\ensuremath{\sigma}$ range, which will be further excluded by upcoming XENON-1T (2017) experiment. also 100 TeV $pp$ can cover most our...
Top squark (stop) plays a key role in the radiative stability of Higgs boson mass supersymmetry (SUSY). In this work, we use LHC Run-1 data to determine lower limit right-handed stop natural SUSY scenario, where higgsinos χ˜1,20 and χ˜1± are light nearly degenerate. We find that has been excluded up 430 GeV for mχ˜10≲250 540 mχ˜10≃100 by searches 2b+ETmiss 1ℓ+jets+ETmiss, respectively. small strip parameter space with mχ˜10≳190 GeV, can still be as 210 compatible measurement monojet bound....
We discuss a cosmological phase transition within the Standard Model which incorporates spontaneously broken scale invariance as low-energy theory. In addition to fields, minimal model involves light dilaton, acquires large vacuum expectation value (VEV) through mechanism of dimensional transmutation. Under assumption cancellation energy, dilaton develops very small mass at 2-loop order. As result, flat direction is present in classical dilaton-Higgs potential zero temperature while quantum...