This series consists of talks in the areas of Particle Physics, High Energy Physics & Quantum Field Theory.
Final states involving hadronic jets are an important background to new physics processes in colliders, as well as a probe of QCD over a large range of energies. Because the physics of jets involves multiple energy scales, they are both complex theoretically and ideally suited to study using effective field theory techniques. In this talk I will discuss some recent progress in using effective field theory to describe the physics of jets.
It is usually assumed that dark matter direct detection is sensitive to a large fraction of the dark matter (DM) velocity distribution. I will explain an alternative form of dark matter-nucleus scattering which only probes a narrow range of DM velocities due to the existence of a resonance, a DM-nucleus bound state, in the scattering - resonant dark matter (rDM). The scattering cross section becomes highly element dependent, has increased modulation and as a result can explain the DAMA/LIBRA results whilst not being in conflict with other direct detection experiments.
When a pair of particles is produced close to threshold, they may form a bound state if the potential between them is attractive. Can we use such bound states to obtain information about new colored particles at the LHC? I will discuss the relevant issues using examples from the MSSM and other beyond the standard model scenarios.
Supersymmetry is a leading candidate for physics Beyond the Standard Model. However, a tree level in the Minimal Supersymmetric Standard Model the Higgs boson should be lighter than the Z boson. LEP did not discover the Higgs boson, so typically large radiative corrections are required to push the Higgs above the LEP lower limit, leading to fine tuning issues. In this talk I will describe how to avoid limits from the searches at LEP and discuss a potential early signal of a 90 GeV Higgs at the LHC.
The BCFW recursion relations define Yang-Mills and gravity amplitudes in terms of lower-point amplitudes. I will discuss several connections between the internal consistency of this recursive definition and the allowed interactions of massless, higher-spin particles.
Recent data from the PAMELA, Fermi/LAT and INTEGRAL/SPI experiments, among others, give evidence of excess electrons and positrons in the galaxy, which might be due to annihilation of dark matter. Models in which the dark matter transforms under a hidden nonabelian gauge symmetry can naturally account for the unusual features needed to fit these data. I will discuss generic features of such models, some of their distinctive consequences for cosmology, and new results for reconciling their predictions with the anomalous observations.
We explore a new scenario explaining mass origin of standard model (SM) particles without a Higgs boson. In this framework SM W, Z gauge bosons and fermions are composites getting masses from confinement of substructure at IR (conformal symmetry breaking). Therefore here SM electroweak gauge symmetry and its breaking are IR emergent phenomena. Using AdS/CFT we build a calculable warped 5D model. Realistic mass spectrum and good fit to electroweak precision data (S, T parameters) can be obtained.
We derive constraints on the sign of couplings in an effective Higgs Lagrangian using prime principles such as the naturalness principle, global symmetries, and unitarity. Specifically, we study four dimension-six operators, O_H, O_y, O_g, and O_gamma, which contribute to the production and decay of the Higgs boson at the Large Hadron Collider (LHC), among other things.
In generalized models of gauge-mediated supersymmetry breaking, a standard model-like Higgs boson can decay to pairs of neutralino superpartners. If the energy scale of supersymmetry breaking is very low, each of these neutralinos will subsequently decay promptly to a photon and a gravitino. This process gives rise to a collider signal consisting of a pair of photons and missing energy.