Narrow Results

The SUSY signals in the dominant stau-neutralino co-annihilation region at LHC are investigated. The region is consistent with the WMAP measurement of the cold dark matter relic density as well as all other current experimental bounds within the mSUGRA framework. The signals are characterized by an existence of very low-energy tau leptons in the final state due to small mass difference (ΔM) between and . We show that for ΔM = 9 GeV and with 30 fb^-1 of data, we can measure ΔM to 15% and to 6%.

Supersymmetric scenarios with R-parity violation have been investigated by the H1 and ZEUS collaborations at HERA using ep collision data collected in 1994-2000. Constraints have been derived for several models (unconstrained MSSM, mSUGRA, GMSB) and for a wide range of the model parameters. The limits are competitive respect to other colliders and to high-precision low-energy experiments.

Many searches for physics beyond the Standard Model have been performed at LEP. In this paper searches for topologies expected from the Gauge Mediated Supersymmetry Breaking model and from various models with extra spatial dimensions, based on typically 600 pb^-1 of data at , are presented.

We review the use of invariant mass distributions in cascade decays to measure the masses of New Physics (NP) particles in scenarios where the final NP cascade particle is invisible. We extend earlier work by exploring further the problem of multiple solutions for the masses.

I provide an introduction to experiments designed to detect WIMP dark matter directly, focussing on building intuitive understanding of the characteristics of potential WIMP signals and the experimental techniques. After deriving the characteristics of potential signals in direct-detection experiments for standard WIMP models, I summarize the general experimental methods shared by most direct-detection experiments and review the advantages, challenges, and status of such searches. Experiments are already probing SUSY models, with best limits on the spin-independent coupling below 10^-7 pb. Combined information from direct and indirect detection, along with detection at colliders, promises to teach us much about fundamental particle physics, cosmology, and astrophysics.

The latest status of LHC and the performances of ATLAS and CMS detectors are summarized in the first part. Physics potential to solve the origin of the ElectroWeak Symmetry Breaking is summarized in the 2nd part, focusing especially on two major scenarios, (1) the light Higgs boson plus SUSY and (2) the Strong Coupling Gauge Theory. Both ATLAS and CMS detectors have the excellent potential to discover them, and we can perform crucial test on the ElectroWeak Symmetry Breaking.

The Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) is efficiently collecting data at luminosities above 3 × 10³³ cm⁻² s⁻¹. Recent running has seen increases in the average number of interactions per bunch crossing, testing the capabilities of the tracking and trigger systems. CMS physics results on approximately 1 fb⁻¹ of data collected at are presented, including results of searches for the Higgs boson.

The present status of the LHC and its experiments are presented. The short and long term programs are also discussed.

After the discovery of a Higgs-like boson with a mass of m_h ≈ 125 GeV at the LHC, we can now attempt to draw conclusions about physics beyond the Standard Model. I argue that there are several hints towards new physics at intermediate scales Λ ≳ 10⁸ GeV. I review a class of stringy models with intermediate scale SUSY which relate the observed Higgs mass to symmetries of the Higgs sector. I then discuss radiative corrections to m_h, unification, dark matter and the possibility of classically unstable UV completions in these models.

New results from the LHC are increasingly probing the borders of the Standard Model of particle physics. Some of the most attractive scenarios for new physics are supersymmetric models. In addition to solving some of the shortcomings of the Standard Model (e.g. the hierarchy problem, gauge coupling unification) they also provide a suitable Dark Matter candidate, which could be produced at the LHC. We present the latest searches for Supersymmetry in events with high-energy final states and large missing transverse momentum using 4.7 fb⁻¹ of proton-proton collisions at as recorded by the ATLAS detector at the Large Hadron Collider. The data is interpreted in models where the Dark Matter candidate is dominantly produced in cascade decays of heavier unstable supersymmetric particles together with high-p_T Standard Model particles. We also present more model-independent searches for one single highly energetic jet or photon together with large amount of missing transverse energy, showing the first results for a mono-jet analysis. Such signals are highly relevant for Dark Matter studies and assume that the DM candidates are pair-produced at the LHC and that all other particles are too heavy to be produced directly. So far no excess above the Standard Model background expectation is observed.

Questions to discuss:

• Does finding the 125 GeV Higgs boson exclude all other possible mass creation mechanisms?
• Is this the SM Higgs boson? How much space is left for extensions (like the SUSY Higgs sector)?
• How special is the 125 GeV mass in view of the top mass? (What happens to the future of particle physics if the EW vacuum is stable?)
• How does the 125 GeV Higgs boson orient the plans for the next colliders, ILC and/or FCC?
• Is there any role of the Higgs boson in the evolution of the universe?