The recent observation of discrepancies in the muonic sector motivates searches for the yet undiscovered atom true muonium (μμ). To leverage potential experimental signals, precise theoretical calculations are required. I will present the on-going work to compute higher-order corrections to the hyperfine splitting and the Lamb shift. Further, possible detection in rare meson decay experiments like REDTOP and using true muonium production to constrain mesonic form factors will be discussed. 1 Int oduction Given the dearth of clear signals beyond the Standard Model (BSM) from the LHC, it may prove useful to consider more subtle deviations from well-understood observables. Under this paradigm, one might organize future searches around resolving the “muon problem”: the curio s coincidence that multipl observables in the mu nic sector devi te from either theoretical predictions or similar resul s with other leptonic flavors. The most persistent devia ion is he the anomalous magnetic mome t aμ m asured at Brookhaven [1] to deviate by ≈ 3σ from th theoretical predictions. Upcoming experi ents at Fermilab [2] and J-PARC [3] ar expected to reduce the experimental uncert inty by a factor of four. Simultaneously, the largest two theoretical uncertainties, the hadronic vacuum polarization and hadronic light-by-light, are expected to be reduced sufficiently that if the current mean values persist, the discrepancy would exceed 5σ. Another long-standing discrepancy in the low energy s ctor, the charge radii from muonic atoms [4, 5], appears to be resolving itself with electronic measurements [6] with near-term experiments to clarify this issue further. If rectified in favor of the muonic results, these observables will put stringent constraints on new physics. At higher energies, the ratio of leptonic decays in D and B mes ns have found 2 − 4σ discrepancies with expectations [7–11]. A new class of observables that can shed light on the muon problem are those associated with the bound state (μμ) [12–15]. This state has alternatively been dubbed “true muonium” [16], “bimuonium” [17], and “dimuonium” [18]. Simpler bound states like positronium (ee), hydrogen, and muonium (μe) have attracted significant attention as testing ground for precision QED studies [19], but are limited in their BSM discovery potential by either the mass suppressionO(me/ΛBS M) or large theoretical uncertainties from unknown nuclear structure effects. In contra t, true mu ium has a much larger reduced mass (μ = mμ 2 ), and its QCD corrections re limited to the better-understood hadronic loop effects. e-mail: hlamm@umd.edu e-mail: yao.ji@physik.uni-regensburg.de Alas, true muo ium has yet to be directly observed. The first reason s that it is experimentally difficult to producing low-energy muon pairs, and is exacerbated by the bound state’s short lifetime (τ ≈ 1 ps), which presents an interesting challenge to experimenters. A second, more prosaic, reason for the neglect is until the aμ anomaly, it seemed unlikely true muonium would offer any novel physics justifying the large effort. In this talk, we pr sent state of the art theoretical predictions for key energy splittings and lifetimes. Following this, we discuss the possibilities to observe true muonium in upcoming experiments.

The European XFEL is a hard X-ray free-electron laser (FEL) based on a high-electron-energy superconducting linear accelerator. The superconducting technology allows for the acceleration of many electron bunches within one radio-frequency pulse of the accelerating voltage and, in turn, for the generation of a large number of hard X-ray pulses. We report on the performance of the European XFEL accelerator with up to 5,000 electron bunches per second and demonstrating a full energy of 17.5 GeV. Feedback mechanisms enable stabilization of the electron beam delivery at the FEL undulator in space and time. The measured FEL gain curve at 9.3 keV is in good agreement with predictions for saturated FEL radiation. Hard X-ray lasing was achieved between 7 keV and 14 keV with pulse energies of up to 2.0 mJ. Using the high repetition rate, an FEL beam with 6 W average power was created. The first operation of the European X-ray free-electron laser facility accelerator based on superconducting technology is reported. The maximum electron energy is 17.5 GeV. A laser average power of 6 W is achieved at a photon energy of 9.3 keV.

In September 2017 the European XFEL entered user operation after several years of construction and commissioning. To provide a fast and flexible commissioning of the various sections of the machine, the high-level control software was essential already from the beginning. While progressing in commissioning and increasing operation parameter space, the enormous complexity of the European XFEL put hard requirements on the control and operation concepts. Having now the full baseline parameters reached, this paper will review the concepts and architecture of the control system in respect to effectiveness, reliability and ease of operation. Basic software concepts and design ideas but also general operation concepts, interoperability between various systems can now be reviewed in respect to the overall facility performance. SOME HISTORY – BIRTH OF THE HIGH-LEVEL CONTROLS GROUP Already in summer 2014 a group of people from various machine related sub-groups came together to form the socalled High-Level Controls (HLC) group. This concept arose from the lessons learned at the Free Electron Laser in Hamburg (FLASH) in Germany and the commissioning of the Linac Coherent Light Source (LCLS) in the US. Within both of these projects it showed up that a simple bottomup approach for implementing higher level software often falls short. The complexity of such modern machines today is that large that a step-by-step commissioning of individual sub-components is often either not possible or at least not economically efficient. These days the software plays a key role when it comes to integrating sub-systems and establishing full interoperability between the various components. The proper functionality of sub-systems can mostly only be established if the whole software envelope is in place and active. To overcome these now known problems it has been decided to form an expert group concentrating on these topics exclusively. Even though at this point in time only the injector complex, consisting of a photo cathode gun and two accelerating modules existed, the group already addressed topics still years ahead. This allowed for grasping possible very complex and therefore time-consuming tasks and addressing these already at this early stage. One such example is the proof of concept for the, that days only envisioned and later on implemented, central data acquisition system (DAQ) (see [1] and [2]). Using some of the already existing server nodes a simulated environment has been set up to mimic the estimated data rates such a DAQ system would need to cope with. Even if the aim of this setup has been to show that such an architecture can cope with the data rates, soon it showed up that such a system can serve for many testing and development purposes. Such a virtual accelerator not only allows to test and debug software components but also can serve as a testbed for graphical user interfaces. E.g. have here new concepts and ideas for the visualization of the complex beam distribution and bunch train dimension been developed. The system has later on been called the Virtual European XFEL and is still being developed further [3]. Even thus within the first years the commissioning of the injector complex had highest priority, the scope had always been to establish software components, interfaces and the overall architecture with the full facility in mind. Fundamental decisions like supported languages, operating systems and control system interoperability have been a major topic at this stage. A lesson learned – here from the European XFEL commissioning – is to fix these decisions prior to starting the work, but also allow for late changes. Thus has the decision to support the python language been taken at a late stage, but the strong requests and lively discussions finally resulted in this outcome, which nowadays no one would question.

The European XFEL is a Hard X-ray Free Electron Laser based on superconducting accelerator technology. In operation since 2017, it now serves 3 FEL beamlines simultaneously for user experiments. We will report on the present operation of the linear accelerator, the beam distribution to the various beamlines and the performance of the FEL radiators.

At the European XFEL a hard X-Ray SASE FEL (SA-SE1) and a soft X-Ray SASE FEL (SASE3) share in series the same electron beamline. This configuration couples the operation conditions for both undulators and their subsequent user experiments in terms of SASE intensity and background. We report on our experience in parallel operation and discuss the solutions that enable the operation of both undulators as independently as possible.

The European XFEL (E-XFEL) is a 3.4 km long X-ray Free-Electron Laser facility and consists of a superconducting, linear accelerator with initially three undulator beam lines. The construction and installation of the E-XFEL is being completed this year and commissioning is well underway. First photon beams are expected to be available for early users in the second half of 2017. This paper will focus on the control system parts for the linear accelerator with its more than 7 million parameters and highlight briefly its design and implementation. Namely the hardware framework based on the MicroTCA.4 standard, testing software concepts and components at real and virtual accelerator facilities and a well-established method for integrating high-level controls into the middle layer through a shot-synchronized data acquisition allowed for a rapid deployment and commissioning of the accelerator. Status and experiences from a technical and an operational point-of-view will be presented.

After about two years in operation the bunch-synchronized data acquisition as used with the accelerator control system at the European XFEL is being revisited. As we have now gained quite some experience with the current system design it was found to have some shortfalls specifically the offered methods and tools for data retrieval and management. In this paper issues of the current implementation are being discussed and taken as an input for an evaluation of new frameworks readily used by many internet and business companies in the context of modern data collection and management technologies. The main focus is currently put on streaming technologies which are being reviewed with respect to feasibility and adaptability for control system architectures at DESY's accelerator facilities.

Extreme-ultraviolet to x-ray free-electron lasers (FELs) in operation for scientific applications are up to now single-user facilities. While most FELs generate around 100 photon pulses per second, FLASH at DESY can deliver almost two orders of magnitude more pulses in this time span due to its superconducting accelerator technology. This makes the facility a prime candidate to realize the next step in FELs-dividing the electron pulse trains into several FEL lines and delivering photon pulses to several users at the same time. Hence, FLASH has been extended with a second undulator line and self-amplified spontaneous emission (SASE) is demonstrated in both FELs simultaneously. FLASH can now deliver MHz pulse trains to two user experiments in parallel with individually selected photon beam characteristics. First results of the capabilities of this extension are shown with emphasis on independent variation of wavelength, repetition rate, and photon pulse length.

The European XFEL is a 3.4 km long X-ray Free Electron Laser in the final construction and commissioning phase in Hamburg. It will produce 27000 bunches per second at 17.5 GeV. Early 2015 a first electron beam was produced in the RF-photo-injector and the

JAVA DOOCS Data Display (JDDD) [1] is the standard tool for developing control system panels for the FLASH facility and European XFEL. The panels are mainly started on DESY campus. For remote monitoring and expert assistance a secure, fast and light-weight access method is required. One possible solution is using HTML5 as transport protocol, because it is available on many common platforms including mobile ones. For this reason an HTML5 version of JDDD, running in a Tomcat application server, was developed. WebSocket technology is used to transfer the panel image to the browser. In the other direction, mouse events are sent back from the browser to the Tomcat server. Now thousands of existing JDDD panels can be accessed from remote using standard web technology. No special browser plugins are required. This article discusses the general issues of the webbased interaction with the control system such as security, usability, network traffic and scalability, and presents the WebSocket approach.

For the control and optimization of electron beam parameters at modern free-electron lasers (FEL), transverse deflecting structures (TDS) in combination with imaging screens have been widely used as robust longitudinal diagnostics with single-shot capability, high resolution and large dynamic range. At the free electron laser in Hamburg (FLASH), a longitudinal bunch profile monitor utilizing a TDS has been realized. In combined use with a fast kicker magnet and an off-axis imaging screen, selection and measurement of a single bunch out of the bunch train with bunch spacing down to 1µs can be achieved without affecting the remaining bunches which continue to generate FEL radiation during user operation. Technical obstacles have been overcome such as suppression of coherent transition radiation from the imaging screen, the continuous image acquisition and processing with the bunch train repetition rate of 10Hz. The monitor, which provides the longitudinal bunch profile and length, has been used routinely at FLASH. In this paper, we present the setup and operation of the longitudinal bunch profile monitor as well as its performance during user operation.

The Data Acquisition System at the Free-ElectronLaser Hamburg (FLASH) has evolved since its implementation in 2005 into a reliable and versatile system, used for accelerator operations and studies along with a multitude of different photon experiment users, recording about 14 TB in 2008 for experiments only. Recently the DAQ system has been successfully upgraded with new hardware to accommodate increasing demands of beam line experiments, upcoming R&D work at FLASH i.e. for the ILC, and to prepare for the upgrade of the FLASH facility this year. This paper describes the evolution of and experiences with the FLASH DAQ and highlights the key elements of its design to facilitate an expandable yet easily to duplicate system implementation.

The Free Electron Laser in Hamburg (FLASH(1)) at DESY is a user facility. It produces laser light of short wavelengths from the extreme ultraviolet down to soft X- rays. To study, monitor and document the machine performance and parameters and also to collect the results of the user experiment measurements a fast data acquisition (DAQ (2)) system has been developed. A shared memory based buffer manager is the heart of the system. It arranges collected data as events for every LINAC shot. All events can be read by different consumers simultaneously. LINAC feedback and monitoring processes as well as experiment middle layer servers are typical clients of the buffer manager. Any client can also generate its own data and insert it into the same event or produce its own one. The paper will focus on the detailed implementation of the buffer manager and its main features. The experience and the achieved performance will be covered as well.

Remote control systems are becoming more and more important to give us the flexibility to control facilities, provide assistance and intervene in case of problems at any time and from every place. As a global operating group CALICE [2] with approx. 220 members worldwide is dependent on using a remote control system for shifts and monitoring of the data taking. CALICE has at present installed its detector at Fermilab, Chicago, where will run test beam experiments for the next year. The components of the remote control system and kind of use are presented here.