Abstract:The discovery by the ATLAS and CMS experiments of a new boson with mass around 125 GeV and with measured properties compatible with those of a Standard-Model Higgs boson, coupled with the absence of discoveries of phenomena beyond the Standard Model at the TeV scale, has triggered interest in ideas for future Higgs factories. A new circular e + e − collider hosted in a 80 to 100 km tunnel, TLEP, is among the most attractive solutions proposed so far. It has a clean experimental environment, produces high luminosity for top-quark, Higgs boson, W and Z studies, accommodates multiple detectors, and can reach energies up to the tt threshold and beyond. It will enable measurements of the Higgs boson properties and of Electroweak Symmetry-Breaking (EWSB) parameters with unequalled precision, offering exploration of physics beyond the Standard Model in the multi-TeV range. Moreover, being the natural precursor of the VHE-LHC, a 100 TeV hadron machine in the same tunnel, it builds up a long-term vision for particle physics. Altogether, the combination of TLEP and the VHE-LHC offers, for a great cost effectiveness, the best precision and the best search reach of all options presently on the market. This paper presents a first appraisal of the salient features of the TLEP physics potential, to serve as a baseline for a more extensive design study.

First experimental results from the final focus test beam (FFTB) are reported. The vertical dimension of a 47-GeV electron beam from the SLAC linac has been reduced at the focal point of the FFTB by a demagnification of 320 to a beam height of approximately 70 nm.

Residual vertical dispersion can be a significant performance limitation for the LEP collider because the associated vertical emittance increase reduces the luminosity of the machine. To make the search for orbits yielding small vertical emittances fast and deterministic, a simultaneous correction of the closed orbit and the residual dispersion was implemented at LEP. The principle of the correction and the resulting performance gains are discussed.

The biomedical community has asked CERN to investigate the possibility to transform the Low Energy Ion Ring (LEIR) accelerator into a multidisciplinary, biomedical research facility (BioLEIR) that could provide ample, high-quality beams of a range of light ions suitable for clinically oriented, fundamental research on cell cultures and for radiation instrumentation development. The present LEIR machine uses fast beam extraction to the next accelerator in the chain, eventually leading to the Large Hadron Collider (LHC). To provide beam for a biomedical research facility, a new slow extraction system must be installed. Two horizontal and one vertical experimental beamlines were designed for transporting the extracted beam to three experimental end-stations. The vertical beamline (pencil beam) was designed for a maximum energy of 75 MeV/u for low-energy radiobiological research, while the two horizontal beamlines could deliver up to 440 MeV/u. One horizontal beamline shall be used preferentially for biomedical experiments and shall provide pencil beam and a homogeneous broad beam, covering an area of 5 × 5 cm 2 with a beam homogeneity of ±5%. The second horizontal beamline will have pencil beam only and is intended for hardware developments in the fields of (micro-)dosimetry and detector development. The minimum full aperture of the beamlines is approximately 100 mm at all magnetic elements, to accommodate the expected beam envelopes. Seven dipoles and twenty quadrupoles are needed for a total of 65 m of beamlines to provide the specified beams. In this paper we present the optical design for the three beamlines.

His teaching and friendship are very precious. " My thoughts also go to John Irwin. He also taught me a great deal. For the lllll-llei'()tlS ,, discussions, your great patience and disponibility, thank you Jolln. knows the Hamiltonian of a system the solution is simply and elegantly given by the associated Lie transformation applied to the functions associated with the ca.noni('al variables. Althougll this work was known it has not been much al)plied outside of the (:omput.er code M¢-uiylieI'al developed by Dragt and his team. One reason for this is, I believe, the (lecomposition chosen in order to separate the effects of different orders in a product of indepcnldent Lie transformations. This stems directly from the Factorization Theorem I''_lof Dragt and Finn. Even for simple elements it is sometimes non-trivial to find this decomposition at order ,,e higher than three; fift, h order contributions for most elements are now being incorporated to 8" MaI:y1ie. A silnpler fornmt_tion was then proposed [_'°1 by John h'win _.nd used for th(' first time at the FFTB for the analysis of the optics. The expansion used is simpler since it consists only in the separation of linear and nonlinear terms. The design linear terms are then treated using the matrix formalism while the non-linear terms are treated separately. The concatenation is performed using the CBH theorem. The simplification arises mostly i'r()n_ the fact. that the arguments of the Lie transformations are mostly the potentials of the elcnlents to be considered, which are e_usilyaccessible. Chapter 2 exposes the :natheniatical ha.sis needed _o establish the 1)hysics in chal)ter 3. The theory of Lie groups and Lie algebra is generally non trivial. However the subset needed for the application to optics is simple. The notions of L;'_ algebra and operators on these algebras are reviewed. Then the central definition of the Lie t,ransformation is 1)res('nt.ed.°T he simple examples oi' the uniform motion and the harmoni(oscillator ar_' (l_'tailed, using m" both the resolution of the equations of motion derived ft'ore Hmnilton's equati(nls, an(l the apl_lication of the Lie transfornlation. These two exanll)les a.r_' v(':'v similar t¢_th(, ('as_, of