In its basic modes, FCC-ee is a factory for Z and W bosons, the Higgs scalar, top quarks and flavoured Standard Model particles. As a consequence, with FCC-ee we will be able to test in clean and precise experimental conditions the entire spectrum of the Standard Model electroweak physics programme. On top of that, the anticipated electroweak precision studies will allow us to set up a...
Increasingly funders of public investment in science and technology require applicants to demonstrate the expected socio-economic returns of their projects. While the scientific case is obviously the top priority for researchers when they propose a new project, it is helpful to know why and how the funders have an interest on impact studies, and what is the potential reward for scientists to...
Building on international practice and previous experience in evaluating the socio-economic impacts of Big Science projects, a model to estimate the future impacts of FCC-ee has been developed. This presentation will recall the definitions of the impact pathways considered and the fundamental assumptions used to perform the analysis.
In order to achieve its ultra-low vertical emittance (1 pm) and high luminosity (of up to $230 \times 10^{34}$~cm$^{-2}$~s$^{-1}$ per collision point), the e$^+$e$^-$ Future Circular Collider (FCC-ee) requires a well-informed alignment strategy, powerful correction methods, and good understanding of the impact of vibrations. The large ring size, high natural chromaticity, small $\beta^*$, and...
Collective effects due to the high beam intensities in FCC-ee, in particular for the Z-pole configuration, are very important for reaching the design performance. While resistive wall represents a major source of impedance for such a large machine, also other contributions, such as that of the bellows with included RF fingers, cannot be neglected. We have studied the single beam instabilities...
Collective effects are very important for the FCC-ee collider due to very extreme parameters, such as the high beam current. Taking into account the updated impedance model, new results of beam dynamics simulations for FCC-ee will be presented. We will analyse the longitudinal microwave instability threshold studying bunch length and energy spread versus beam current, and TMCI, transverse mode...
In this work, we present updates on the electron cloud build-up studies considering various sections of the FCC-ee. Additionally, we report arc dipole & drift regions using the new baseline beam parameters for four IPs. Furthermore, estimated threshold central electron densities for the single-bunch instability are included. The electron density at the center of the beam pipe for 30 ns and 32...
I will motivate the BSM theory case for the FCC physics programme and give a general outline of the various scenarios it will be able to explore to an unprecedented level.
Current strategy and ongoing activities will be presented, in relation to R&D and preparation of production for the elliptical cavities needed by FCC
In this contribution we will give an overview of the status of the design of the pre-injector complex and introduce the new layout that has been proposed by the study group working in the context of the CHART collaboration. A summary of the injector parameters focusing on the most challenging ones for the different injector sub-systems will also be presented.
In the frame of the Future Circular Collider (FCC) study, CERN is modelling the copper electropolishing process. The aim is to foresee and optimise the process parameters such as cathode geometry, bath flow and temperature, and minimum potential input, namely on the 400 MHz single cell FCC type cavities and thus contributing in achieving the ultimate performance on the Nb/Cu technology. In...
The two stage FCC program with electron positron and proton proton collision offers a unique opportunity to search for long lived particles in a clean electron positron environment as well as in high energy high luminosity proton proton collisions. I take an overview of the opportunities for searching for long lived particles both at FCC-ee and FCC-hh. I present several examples of motivated...
In this presentation, I will give an overview of the beam dynamics simulations done to optimize the design of two of the linacs in the FCC-ee injectors’ complex. The first one accelerates electrons from 200 MeV up to 1.54 GeV, and for both electrons and positrons from 1.54 GeV up to 6 GeV. In particular, I will focus on some of the possible mechanisms of single-bunch emittance degradation and...
The Future Circular Collider (FCC) study focuses on the design and technology developments of a new research infrastructure capable of hosting the next generation of particle colliders at CERN. CERN developed significant know-how in the design and fabrication of niobium-coated copper superconducting radiofrequency (SRF) cavities for accelerators, from the Large LEP, to the LHC, and HIE-ISOLDE....
The linacs of the FCCee injector complex will both provide the drive beam for position production and accelerate nominal electron and positron beams up to 6 GeV. Several linacs comprise different traveling-wave structures fulfilling the beam dynamics and RF constraints. High-phase advance large-aperture structures accelerate the positron beam at low energies. All structures are rotationally...
The presentation shows a simulation and optimisation of the FCC-ee positron source using a high-temperature superconducting (HTS) solenoid as the matching device to collect positrons downstream of the target. The conventional target scheme composed of simply a single tungsten is used. The target is placed inside the bore of the HTS solenoid to improve the positron yield. The position of the...
The innovative concept of two-stage multi-beam Klystron has been previously proposed and studied for a 1GHz 20MW Klystron for CLIC. This technology utilizes low voltage electron beam in its first stage to reduce the overall tube length, followed by DC post acceleration in the second stage to ensure ultra-high efficiency. This topology is very practical to provide compact design at a low...
For an electron-positron collider like FCC-ee, the production of positrons plays a crucial role. One of the design options considered for the FCC-ee positron source employs a superconducting solenoid made of HTS coils as an adiabatic matching device. A superconducting solenoid yields a higher peak field than a conventional flux concentrator, therefore increasing the achievable positron yield....
An innovative superconducting cavity topology has been recently proposed at CERN and at Lancaster University. It integrates longitudinal slots crossing perpendicularly the RF surface. The RF current lines run along the slots, inducing no perturbation of the accelerating mode. Thanks to this approach, the cavity can be built using halves or quadrants, which is well appropriate to precise...
One of the main objectives of FCCee is the precise measurements of Standard Model parameters, like the couplings of the Higgs boson to the bottom and charm quarks and gluons. This requires an efficient reconstruction and identification of the hadronic final states of these processes, which entails identifying the flavour of the parton that initiated the jet, referred to as jet-flavour tagging....
The current proposal for the FCC-ee injector complex includes separate linacs to accelerate the electron and positron beams to 1.54 GeV, followed by a common linac to bring the beams to 6 GeV. Electron and positron transfer lines will be needed to connect these elements. There will be a damping ring for the 1.54 GeV positrons, after which a transfer line will transport the positron beam to the...
P-cubed, currently in development at PSI, is the proposed proof-of-principle experiment for the FCC-ee positron source. Capture and transport of the secondary positron beam from the production target to the damping ring are a key challenge for FCC-ee, due to large emittance and energy spread. The use of novel matching and focusing methods has been studied, such as high temperature...
The recent measurement of the W mass by the CDF collaboration at the Tevatron in hadron collisions has created a significant buzz in the community. Quite apart from the fact that it disagrees significantly both with the Standard Model predictions and with previous measurements of this quantity, this result is remarkable by two aspects:
- the systematic error is of the same size as the...
In this talk, I review the current status of the FCC-hh ring layout and optics studies, starting from a brief overview of the CDR status and then moving to the recent developments. I also provide an outlook for future studies and activities.
The Future Circular electron-positron Collider, FCC-ee, is designed for unprecedented precision for particle physics experiments from the Z-pole to above the top pair threshold. This demands a precise knowledge of the center-of-mass energy (ECM) and collision boosts at all four interaction points.
Synchrotron radiation losses range from 40 MeV per turn at the Z-pole with 45.6 GeV beam energy,...
Precise energy calibration is a key tool for the FCC-ee physics programme and will be obtained by resonant depolarization. It requires the implementation of a Compton polarimeter with unprecedented performance. The presentation is mainly devoted to the description of the foreseen laser performance and the associated challenges.
For the design of FCC trajectory, a full understanding of the subsurface geology that will be crossed by both the tunnel and the access shafts is required. For this purpose a detailed knowledge of the regional distribution of rock mass composition and structural elements as well as the hydrogeological characteristics of the area should be achieved and summarised in a full-scale 3D geological...
The future circular electron-positron collider (FCCee) is receiving much attention in the context of the FCC Feasibility Study currently in progress in preparation for the next EU strategy update. We present IDEA, a detector concept optimized for FCCee and composed of a vertex detector based on DMAPS, a very light drift chamber, a silicon wrapper, a dual readout calorimeter outside a thin 2...
Very high luminosities at the production poles (z,w,h,t) of FCC-ee are planned at the four Interaction Points (IP); thus very low beta star values are required at the IP, implying the use of very strong quadrupoles. Concurrently, LAPP work has underlined the strong correlation between the vibrations of the quadrupoles due to ground motion amplified by the dynamics of the cryostat in cantilever...
This presentation will briefly talk about error propagation in alignment networks in tunnels. It will also give a summary of alignment experiences that were reported at the FCC-ee optics tuning and alignment mini-workshop. Finally the presentation will show some results from SLAC in particular and the importance of alternate measurement methods added to conventional laser tracker and leveling...
A design is presented for the instrumentation of the very forward region in future detectors at e+e- collider to perform a fast estimate and precise measurement of the luminosity, to improve the hermeticity and mask the central tracking detectors from backscattered particles. Two compact calorimeters are foreseen, LumiCal and BeamCal. Both are designed as sandwich calorimeters with very thin...
In short, Geodesy deals with two main topics. (1) The determination of the position of (all) objects on the Earth or in its vicinity. (2) The determination of the gravity field and its geometry. Since the beginning of mankind those tasks serve science and society. The first scientific question concerned the shape of the Earth, and the first societal application concerned the rational...
The talk presents the status of MAD-X code and recent developments related in particular to FCC-ee studies.
For the construction and maintenance of large-scale infrastructure such as the Gotthard Base Tunnel or the CERN-FCC, it is vital to take into account the influence of the varying gravity field, because most geodetic measurements are referring to the local plumb lines and equipotential surfaces, deviating from purely geometrical positioning by e.g. GNSS.
The so-called Geoid, an equipotential...
Two possible scenarios for measuring the frequency of spin precession in FCC-ee storage rings at the threshold of the birth of Z and WW-pairs are discussed. One of the scenarios involves the use of the well-known method of Resonant Depolarization of pilot bunches of the pre-polarized particles. While in the second approach it is proposed to use a powerful short-pulse RF magnet (flipper) to...
The Future Circular Electron–Positron Collider (FCC-ee) will be 91 km long and operate in a top-up mode where new beams are continuously injected into the collider. For this purpose, the collider tunnel will also house a 91 km long booster accelerator. During its life cycle, the FCC-ee will operate with different energies to study Z, W, and H bosons and the top quark. The Future Circular...
While the manufacturing industry is strongly engaged in robotization, the construction field is still facing important scientific and technical challenges in this area. Indeed, this sector requires that robots work in large spaces, in accurate ways, on very varied activities where know-how must be adapted to complex environments. Therefore, we present several industrial studies that Nantes...
The most relevant challenges of telerobotics technologies for the coming years are precise manipulation in semi-structured environments, high levels of tightening torque, and reduced execution time. Also, an iterative design of remote handling processes is necessary to comply with maintenance requirements properly. Other aspects to consider are operator training and robot recovery strategies,...
The design of the interaction region of the positron-electron future circular collider must comply with various important constraints, imposed by high beam energy, high luminosity, need for polarization, and crossing scheme. An overview of the MDI design will be presented with a picture of the recent updates in the layout and ongoing studies. The status of the MDI activity will be summarised...
The FCC-ee will be the largest accelerator ever built with kilometers of different accelerator devices. The identification of the main loads is crucial for designing the electricity infrastructure and for evaluating its energy consumption. An update of the FCC power demand is ongoing with the evaluation of its annual energy consumption depending on the machine configurations. The next step is...
The beam parameters of FCC-ee with its high-intensity beams and large dynamic range lead to exceptional requirements for beam instrumentation devices. For high energy lepton machines, the detection of synchrotron radiation for the measurement of bunch length has been common practice in the past. However, given the exceptional size of FCC-ee, extracting synchrotron light comes with technical...
Currently a semi-passive beam dilution system is foreseen for the FCC-ee beam dumping system. This system utilizes passive beam diluters (spoilers) made from carbon-based materials. To test the performance of these spoilers, an experiment was carried out in November 2021 at CERNs HiRadMat Facility with scaled prototypes of the proposed spoiler design. By using special beam optics to mimic the...
This presentation is about the modelling process for vibrations estimations used at LAPP (Annecy's particle physics laboratory) for the FCC project. The main goal of this work is to be able to predict the magnets displacements knowing only the ground displacements. The presentation explains the connection between mechanical calculations and optics studies. It also describes the different steps...
The precise alignment and monitoring of the FCC-ee MDI is mandatory in order to reach the designed luminosity. Though, the extremely elegant but also complex MDI design raises some tough challenges.
This presentation will underline the different challenges and explain why they represent difficulties for the design of an alignment and monitoring system. Subjects such as design, technology,...
Logistic of equipment and personnel is a major aspect during the assembly, installation but also operation of the future FCC. The transport and handling tools and means need to be studied in details, in an early phase, in order to control the associated costs as well as the duration of interventions.
The presentation will give an overview on the requirements for the special vehicles...
Fraunhofer-IML has analyzed several logistics and handling aspects during the FCC Conceptual Design phase. As part of the feasibility study phase, the key accelerator parameters are being redefined and the existing basic concepts for logistics and material handling vehicles will thus be reviewed and developed in more detail. Within this phase, the studies will focus on three main areas of...
The interaction region for the Future Circular Collider FCC-ee at 182.5 GeV is a sensitive section of the accelerator. The synchrotron radiation produced in the surrounding environmnent of the detector can result in background or damages to the hardware. The studies will present the deposited synchrotron radiation power from the magnetic elements included in the interaction region as well as...
Global fits to electroweak precision data, comparing the measured values of different quantities with the SM predictions, provide important checks of the SM consistency and sensitivity to beyond-the-SM (BSM) effects. The two most sensitive determinations of $\sin^2 \theta_{\rm eff}^{\rm lep}$, from the LEP measurement of $A_{0,b}^{FB}$ and the SLD measurement of $A_\ell$,
are in...
The successful identification of strange quark jets at the FCC-ee would enable the study of a multitude of largely unexplored processes, including the first ever study of Z->ss production, rare Higgs boson decays and the strange Yukawa coupling, CKM matrix elements via W decays, and BSM physics scenarios such as FCNCs. Due to the challenging nature of distinguishing these medium-mass quarks,...
Numerous studies and measurements planned at the FCC-ee rely on efficient and accurate jet flavour tagging algorithms, which in turn heavily rely on secondary vertex reconstruction as b and c jets contain long-lived hadrons that decay hundreds of microns from the collision point. At the same time, vertex reconstruction is also an important tool to test the performance of different vertex...
GRAiNITE Studies
Presentation of a new type of sampling ECAL calorimeter. It is of the Shaslik type with WLS fibers, but instead of lead and scintillator plates, it uses a mixture of crystal scintillator grains and heavy liquid. According to Geant 4 studies, the finer sampling allows to reach a resolution < 2%/sqrt(E) A sample of ZnWO4 grains obtained by “spontaneous” flux method...
The Higgs boson trilinear and quartic self-couplings are directly related to the shape of the Higgs potential; measuring them with precision is extremely important, as they provide invaluable information on the electroweak symmetry breaking and the electroweak phase transition.
\In this paper, we perform a detailed analysis of double Higgs boson production, through the gluon-gluon fusion...
A plethora of measurements at the FCC-ee crucially depend on efficient flavour tagging and precise flight distance measurements. To achieve this, the innermost piece of the FCC-ee detectors, the vertex detector, has to precisely locate the collision vertices, while adding only a minimal amount of material to the detector.
The proposed reduction of the beam pipe radius at the FCC-ee from...
Recent analyses on high-energy inclusive Higgs-boson rates in proton collisions via the gluon fusion channel, matched with the state of-the-art fixed-order N$^3$LO accuracy, have shown that the impact of high-energy resummation corrections reaches 10\% at the FCC nominal energies. This supports the statement that electroweak physics at 100 TeV is expected to receive relevant contributions from...
In this work, we derive lower mass bounds on the $Z^\prime$ gauge boson based on the dilepton data from LHC with 13 TeV of center-of-mass energy, and forecast the sensitivity of the High-Luminosity-LHC with $L=3000 fb^{-1}$, the High-Energy LHC with $\sqrt{s}=27$~TeV, and also at the Future Circular Collider with $\sqrt{s}=100$~TeV. We take into account the presence of exotic and invisible...
The cool-down and cryostating of the FCC superconducting magnets requires transport and distribution of large quantities of cryogens over distance up to 10 km. It significantly exceeds the experience gained from the existing Big Science helium cryogenic systems. To limit the pressure drop and the distribution header diameters, cryogens could be distributed at high pressure up to 50 bar. Such...
The design of future lepton colliders, which would push the beam intensity frontier significatively forward with respect to the current state of the art, paves the way to novel technological challenges. In particular, the need for very high positron yield in the linear (ILC and CLIC) or circular (FCC-ee, CEPC) colliders requires that innovative approaches to the positron production are...
High temperature superconductors-coated conductors (HTS-CC) with its significantly low surface impedance at low temperature (below superconducting critical temperature Tc) are being considered a good alternative to Cu as coatings for the beam screen of the hadron-hadron future circular collider (FCC-hh). In particular, rare-earth barium cuprates (REBCO-CC) are excellent candidates considering...
Within the framework of the Future Circular Collider Feasibility Study, the design of the electron-positron collider FCC-ee is optimised. Polarized low intensity pilot bunches are foreseen at the first energy stages to determine the beam energy, and thus sufficient level of polarization must be achieved which can be limited by alignment and optics errors. Additionally, strong synchrotron...
Over the years, it has been observed for cavities in operation in accelerators, a continuous degradation of their performance with the appearance or reinforcement of the parasitic field emission phenomenon. This phenomenon, caused by surface pollution promoting the emission and acceleration of electrons by electromagnetic fields, causes the generation of ionizing X radiations. This poses...
La physique des particules explore l’infiniment petit et permet d’élucider l’évolution de l’Univers depuis ses origines. Bien que la compréhension actuelle, résumé « dans le modèle standard », donne une description avec une précision époustouflante des phénomènes observés, des questions restent ouvertes : le rôle du boson de Higgs, l’asymétrie matière antimatière, la compréhension de la...
capables de résister à des taux d’irradiation sans précédant. Elles devront aussi traiter des flux de données gigantesques, dont il faudra maîtriser la complexité pour extraire des signaux de physique bien dissimulés ou extrêmement rares.
Nous évoquerons les nouveaux paradigmes proposés pour atteindre ces objectifs. Quelques exemples de développements techniques nécessaires, depuis la...
Le futur collisionneur circulaire (FCC) est conçu pour être la prochaine génération de collisionneur de particules à haute performance, qui prendra le relais du LHC, lorsque la phase de haute luminosité (HL-LHC) de cette machine arrivera à son terme, vers 2040.
La mission du FCC sera de repousser les frontières d'énergie et d'intensité des collisionneurs de particules, dans le but...
The physics programme of FCCee requires a particularly high performance vertex detector, where spatial resolution and material budget prevail over radiation tolerance and read-out speed. As of today, CMOS pixel sensors provide promising
perspectives of detection performances matching this requirement ranking. Two CMOS technologies are currently developed for this purpose. Their potential will...
