CERN Accelerating science

The Higgs boson, the most sought-after particle in all of physics, is proving tougher to find than physicists had hoped. [...]

The Higgs boson is the only particle predicted by the Standard Model that has not yet been seen by experiments. It helps explain how elementary particles acquire mass. If the Higgs boson exists it will be produced in proton-proton collisions at the LHC.

Scientists at the Large Hadron Collider say a signal that suggested they might have seen "hints" of the long-sought Higgs boson particle has weakened. [...]

Ripples of excitement swept through the physics community last month when Cern scientists reported what looked like glimpses of the long-sought Higgs boson. But the hopes have been dashed as it was revealed that the tantalising hints had all but faded away. [ ... ]

Read the paper: TOP-11-003

The measured production rates of Top-antiTop pairs, where one lepton and four jets of particles is observed in the final state, show good agreement with Quantum Chromodynamics (QCD), the theory of the strong interaction.

The number of events that an experiment observes is proportional to a quantity called the luminosity — a measure of how many collisions are occurring in the detector.

This year's HCAL test beam run in July was completely devoted to studies of hardware that will be used in the upcoming upgrades. During the course of the two weeks the detector was moved in two independent setups – HF and the combined EB+HB+HO – into various positions relative to the beam.

High-energy collisions with final states that include leptons (electrons, muons or taus) have played major roles in the history of physics. Several particles – such as J/ψ, W, and Z – as well as productions of pairs of Top quarks were discovered in their leptonic decay modes.

CMS published its 100^th paper on 3^rd August. This accomplishment, unprecedented in its pace, came as a result of many things working together extremely well.