Search

Taking advantage of both the high mass resolution of the COSY-11 detector and the high energy resolution of the low-emittance proton beam of the cooler synchrotron COSY, we determine the excitation function for the $\it{pp\rightarrow pp\eta'}$ reaction close to threshold. Combining these data with previous results, we extract the scattering length for the $\it{\eta'}$-proton potential in free space to be $Re(a_{p\eta'}) = 0\pm0.43$ fm and $Im(a_{p\eta'})=0.37_{-0.16}^{+0.40}$ fm.

ATRAP Progress Report on 2010 Antiproton Run

Recent Relevant publications by ATRAP and its Members Overview ATRAP Milestones Looking back at 2008 and Forward to the 2009 Antiproton Run We cannot succeed without antiprotons Optimal Use of Antiprotons The ELENA Advantage References

Based on the notion that the local dark-matter field of axions or axion-like particles (ALPs) in our Galaxy induces oscillating couplings to the spins of nucleons and nuclei (via the electric dipole moment of the latter and/or the paramagnetic axion-wind effect), we establish the feasibility of a new method to search for ALPs in storage rings. Based on previous work that allows us to maintain the in-plane polarization of a stored deuteron beam for a few hundred seconds, we performed a first proof-of-principle experiment at the Cooler Synchrotron COSY to scan momenta near 970 MeV/c. This entailed a scan of the spin precession frequency. At resonance between the spin precession frequency of deuterons and the ALP-induced EDM oscillation frequency there will be an accumulation of the polarization component out of the ring plane. Since the axion frequency is unknown, the momentum of the beam and consequently the spin precession frequency were ramped to search for a vertical polarization change that would occur when the resonance is crossed. At COSY, four beam bunches with different polarization directions were used to make sure that no resonance was missed because of the unknown relative phase between the polarization precession and the axion/ALP field. A frequency window of 1.5-kHz width around the spin precession frequency of 121 kHz was scanned. We describe the experimental procedure and a test of the methodology with the help of a radiofrequency Wien filter located on the COSY ring. No ALP resonance was observed. As a consequence an upper limit of the oscillating EDM component of the deuteron as well as its axion coupling constants are provided., 27 pages, 24 figures, 7 tables, 104 references

This year‘s annual report deviates from the usual IKP annual report because we want to exploit the effort entered into the preparation of the report for the POF evaluation. The report for the evaluation of the IKP activities within the project oriented funding of the Helmholtz association was one of the most important activities in 2017. The report covers nearly all achievements of 2017 and and thus it is highlighted in this annual report, and has been enhanced by including additional information. The highlights of 2017 include further achievements towards electric dipole measurements (JEDI), progress in the preparation of the PANDA detector and in the HESR component construction, results from COSY hadron physics experiments, strong increase of IKP contributions to neutrino physics experiments, a strong incresae in the CLAS analysis and preparation of phase-0 FAIR experiments at HADES. From the finished COSY experiments various scientific results have been produced, such as investigations of the properties of $\eta$ mesons at WASA, and continued analysis of data related to the d*(2380) resonance and the charge symmetry breaking reaction dd->$^{4}$He$\pi^{0}$. During the time before PANDA begins to produce data, the participation in the CLAS data taking and analysis at JLAB is ongoing and for the phase-0 experiments at FAIR a straw tube detector system for the HADES detector at GSI is being built. The preparations for FAIR are ongoing on the accelerator as well as on the experiment side. All dipoles for HESR were now tested and shipped to Darmstadt. The implementation of the HESR project is on time and in budget and also the developments for PANDA are progressing well. The activities towards electric dipole measurements achieved further steps in the aim of ultimate precision in polarization measurement and manipulation by controlling the spin precession rate and phase with a polarization feedback. The neutrino physics activities were extended with contributions to running (Borexino) and future (SOX, JUNO) experiments. Our activities within the different POF programs were very positively evaluated. The committee was impressed by the scientific program and realized that we deliver essential contributions for the various program topics. Our activities were considered as forefront, crucial and outstanding. This very good evaluation result is due to the work of all IKP colleagues during the last years. In spite of the unclear future of IKP the colleagues stayed highly motivated which was impressively demonstrated in the presentations for the POF review committee.

An important milestone has been reached in 2014: The evaluation of both the experimentaland the theoretical proposal for the third period of programme-oriented funding (PoF) of the Helmholtz Association resulted in excellent reports on the proposals presented by IKP. Consequently the base funding of the institute up to the end of 2019 has been secured. The institute thanks Prof. Dr. R. Maier for his strong scientific leadership of IKP-4 during the past thirty years, which has made a major contribution to the success of the IKP. He will continue to support the institute by his ideas and advice. We thank Prof. A. Lehrach for his fine interim management of IKP-4 after Prof. Maier’s retirement in early 2014. On December 1, IKP has welcomed the new director of IKP-4, Prof. Mei Bai.In the next five years, COSY will concentrate on two activities. In preparation of FAIR, COSY will test components of the high energy storage ring HESR and the detector system PANDA. Within the Jülich-Aachen research alliance (JARA), a precursorexperiment for the determination of the electromagnetic dipole moment (EDM) of charged particles in a storage ring will be developed by the JEDI collaboration. The experimental activities in hadron physics at COSY have ended in 2014. The program advisory committee (PAC) has completed its mission in 2014. The research center thanks both present and past members for their expert advice in choosing the most promising experiments. Beam time at COSY remains a precious commodity. The new COSY beam advisory committee (CBAC) will help to make the future COSY activities a success.

During the past year the Institute for Nuclear Physics (IKP) has faced a couple strategicwatersheds. Foremost of these is the upcoming retirement of Rudolf Maier, the head of theaccelerator institute (IKP-4), in early 2014. It is obvious that the accelerator group needsstrong scientific leadership given the tasks and commitments of IKP-4 — in particular in the context of building HESR at FAIR and of conceiving a possible future storage-ring project. Fortunately, the process of interviewing and subsequently hiring a successor to lead IKP-4 in the future is proceeding on track. Moreover, we have decided to phase out the hadron physics program at COSY. On the one hand this is motivated by the upcoming physics opportunities at HESR/PANDA, and on the other side by serious budgetary restrictions imposed on us. Consequently, we have readjusted our priorities as presented in the application for Programme-oriented Funding (PoF-3). Here about 70% of our resources (HESR; PANDA and PAX) are connected with FAIR, which according to a decision by the Helmholtz senate will not be evaluated. The remaining 30% are largely foreseen for the JEDI-project, which aims at a search for charged-particle electric-dipole moments in storage rings with unprecedented sensitivity. A smaller part will be used for research and development of accelerator components and advanced detector technologies. The corresponding PoF-applications for Matter and the Universe (MU) and Matterand Technology (MT), have been submitted and will be evaluated in the first quarter of 2014. In order to strengthen the cooperation between IKP and the physics department of the RWTH Aachen University in the field of basic research, a new section of the Jülich-Aachen Research Alliance (JARA) was founded last year and inaugurated in January 2013. Named JARA-FAME (Forces and Matter Experiments), its aim is to investigate the fate of antimatter (i) by searching for it with the Alpha Magnetic Spectrometer (AMS) on the International Space Station (ISS) and (ii) by investigating possible reasons for its disappearance, e.g., via the search for EDMs within JEDI. The technological highlight of 2013 was the installation and commissioning of the highenergy electron cooler in the COSY ring (see cover page). After delivery in December 2012 by the Budker Institute (Novosibirsk, Russia), it has been set up together with our Russian colleagues. In the meantime it has been tested at lower values of high voltage to prove that it works. As the next step we will study the device in detail with COSY beams and carefully increase the electron beam energy up to the maximum value of 2 MV duringthe upcoming year. Physics highlights of the past year comprise: [...]

A main focus of the Institut fuer Kernphysik (IKP) of Forschungszentrum Juelich (FZJ) is the design and construction of the High Energy Storage Ring (HESR) for the Facility for Antiproton and Ion Reseach (FAIR), which is being built at Helmholtzzentrum fuer Schwerionenforschung (GSI), Darmstadt. A corresponding contract between the FAIR company and FZJ has been signed in 2011 and 65 Me have been assigned for this purpose. An international consortium comprising IKP as the leading institution, the Zentralinstitut fuer Technologie (ZAT) of FZJ, the GSI, the Helmholtzinstitut Mainz (HIM) and the National Institute for R&D in Electrical Engineering (ICPE-CA), Bucharest, will build the HESR in the years up to 2018 and commission it afterwards. IKP is also contributing to the design and construction of the PANDA detector at HESR: after the decision of the PANDA collaboration to use a straw-tube tracker (STT) as the central tracking detector, a cooperation of IKP, Frascati, Pavia and Ferrara (Italy), Cracow (Poland) and Bucharest (Romania) will build the STT and later install it in PANDA. IKP is making essential contributions to the Micro-Vertex-Detector(MVD), as well as conceiving a day-one experiment for PANDA, and is involved in the PANDA pellet target development, together with IHEP (Moscow). In 2011 the Technical Design Reports have been finalized and approved by PANDA to be submitted to FAIR for these three detectors components (MVD, STT, target).

20 I 0 marks the first year of the second period of Program oriented Funding (PoF), the new scheme of providing resources within the Helmholtz Association of German Research Centers. In October a further milestone for the FAIR project was accomplished by signatures of the international agreement on its construction and the subsequent foundation of the FAIR GmbH. The Institut für Kernphysik (IKP) of Forschungszentrtum Jülich (FZJ) is heavily involved in FAIR as the consortiumleader for the construction ofthe High Energy Storage Ring (HESR) and a major contributor to the PANDA detector. In addition IKP is working on a method to produce beams of polarized antiprotons by spin filtering for a possible future FAIRIHESR-upgrade. In October, a Program Advisory Council, chaired by Stephan Paul (TU Munich), was held at IKP to advise IKP and FZJ management on the future plans and strategy of the institute. Besides the IKP program outlined for PoF-2 for COSY and FAIR, the committee strongly endorsed the PAX spin filtering project and the plans to investigate the possibilities of a search for an electric dipole moment (EDM) of proton and/or deuteron ($^{3}$He) at storage rings, which could lead to a future IKP facility. lt also recommended to renew the position of the IKP-4 director (R. Maier) after his retirement in 2014 as early as possible. The followillg experimental and theoretical highlights are worth mentioning: • The decay of the eta into two charged pions and a photon has been measured by the WASA-at-COSY collaboration. • Analyzing powers and cross sections for the reaction $\vec{p}$n $\rightarrow$ (pp)$_{s}$$\pi$$^{-}$ have been obtained at ANKE for a beam energy T$_{p}$ = 353 MeV. The results are in agreement with, but extend, existing data in literature. They allow one to determine the low-energyconstant d in the 4N$\pi$ constant interaction of Chiral Perturbation Theory with very small systematic errors. • The WASA collaboration has obtained new data on two-pion production in the proton-proton reaction at the invariant collision energy $\sqrt{s}$s = 2.46 GeV. The data are not compatible with a conventional double Delta excitation. The COSY-TOF collaboration took data on the reaction $\vec{p}$p $\rightarrow$ pKA and extracted the Kaon analysing power, completing a first step in the determination of the spin triplet proton-Lambda scattering length. • The strong-interaction parameters in pionic deuterium have been measured with unprecedented precision. • Theory has derived the pion-deuteron scattering length from a consistent treatment of both strong and electromagnetic few body effects. The systematic uncertainties of the pion nucleon coupling constant are now controlled, reslilting in g$^{2}_{c}$/4$\pi$ = 13.7 ± 0.2 (see cover).[...]

Particle physics experiments of today depend on and rely upon many people for a successful performance of the experiment, starting from the development of the program to be investigated, continuing with the design and feasibility performance, leading to the construction of the actual experimental setup and coordination,measuring the data under optimal conditions, analyzing the data consistently with as little bias as possible, interpreting the results in view of physics relevance, comparing the results to other quantities and extracting specific measurement categories, publishing the results in the context of relevant, objective and available acquirements and defending the observables in a scientific manner. During the preparation and in the course of the ongoing research the COSY–11 collaboration received support and encouragement from many sides. We appreciate the help from: [...]