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  • 1. Barucca, G.
    et al.
    Makonyi, Karoly
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Preston, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Wölbing, Dirk
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Zmeskal, J.
    The potential of Λ and Ξ− studies with PANDA at FAIR2021Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 57, nr 4, artikel-id 154Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The antiproton experiment PANDA at FAIR is designed to bring hadron physics to a new level in terms of scope, precision and accuracy. In this work, its unique capability for studies of hyperons is outlined. We discuss ground-state hyperons as diagnostic tools to study non-perturbative aspects of the strong interaction, and fundamental symmetries. New simulation studies have been carried out for two benchmark hyperon-antihyperon production channels: p¯p→Λ¯Λ and p¯p→Ξ¯+Ξ−. The results, presented in detail in this paper, show that hyperon-antihyperon pairs from these reactions can be exclusively reconstructed with high efficiency and very low background contamination. In addition, the polarisation and spin correlations have been studied, exploiting the weak, self-analysing decay of hyperons and antihyperons. Two independent approaches to the finite efficiency have been applied and evaluated: one standard multidimensional efficiency correction approach, and one efficiency independent approach. The applicability of the latter was thoroughly evaluated for all channels, beam momenta and observables. The standard method yields good results in all cases, and shows that spin observables can be studied with high precision and accuracy already in the first phase of data taking with PANDA.

  • 2. Barucca, G.
    et al.
    Preston, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Wölbing, Dirk
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    PANDA Phase One2021Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 57, nr 6, artikel-id 184Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of hadron-, nuclear- and atomic physics experiments. The future antiProton ANnihilations at DArmstadt (PANDA or PANDA) experiment at FAIR will offer a broad physics programme, covering different aspects of the strong interaction. Understanding the latter in the non-perturbative regime remains one of the greatest challenges in contemporary physics. The antiproton-nucleon interaction studied with PANDA provides crucial tests in this area. Furthermore, the high-intensity, low-energy domain of PANDA allows for searches for physics beyond the Standard Model, e.g. through high precision symmetry tests. This paper takes into account a staged approach for the detector setup and for the delivered luminosity from the accelerator. The available detector setup at the time of the delivery of the first antiproton beams in the HESR storage ring is referred to as the Phase One setup. The physics programme that is achievable during Phase One is outlined in this paper.

  • 3. Barucca, G.
    et al.
    Zimmermann, I.
    Makonyi, Karoly
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Preston, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Wölbing, Dirk
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Zmeskal, J.
    Feasibility studies for the measurement of time-like proton electromagnetic form factors from ̄pp→μ+μ−at PANDA at FAIR2021Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 57, nr 1, artikel-id 30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reports on Monte Carlo simulation results for future measurements of the moduli of time-like proton electromagnetic form factors, vertical bar G(E)vertical bar and vertical bar G(M)vertical bar, using the (p) over barp -> mu(+)mu(-) reaction at PANDA (FAIR). The electromagnetic form factors are fundamental quantities parameterizing the electric and magnetic structure of hadrons. This work estimates the statistical and total accuracy with which the form factors can be measured at PANDA, using an analysis of simulated data within the PandaRoot software framework. The most crucial background channel is (p) over barp -> pi(+)pi(-), due to the very similar behavior of muons and pions in the detector. The suppression factors are evaluated for this and all other relevant background channels at different values of antiproton beam momentum. The signal/background separation is based on a multivariate analysis, using the Boosted Decision Trees method. An expected background subtraction is included in this study, based on realistic angular distributions of the background contribution. Systematic uncertainties are considered and the relative total uncertainties of the form factor measurements are presented.

  • 4. Cederlof, E. Ahlgren
    et al.
    Back, T.
    Nyberg, J.
    Qi, C.
    Atac, A.
    Badran, H.
    Braunroth, T.
    Calverley, T.
    Cox, D. M.
    Doncel Monasterio, Maria
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. University of Salamanca, Spain.
    Grahn, T.
    Greenlees, P.
    Hilton, J.
    Julin, R.
    Juutinen, S.
    Konki, J.
    Li, H.
    Matta, S.
    Modamio, V.
    Singh, B. S. Nara
    Pakarinen, J.
    Papadakis, P.
    Partanen, J.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Stolze, S.
    Subramaniam, P.
    Uusitalo, J.
    Valiente-Dobon, J. J.
    Lifetime measurement of the yrast 2+state in118Te2023Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 59, nr 12, artikel-id 300Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The electromagnetic transition probabilities of the yrast 2+ states in the midshell Te isotopes, two protons above the closed shell at Sn, are of great importance for the understanding of nuclear collectivity in these isotopes and the role played by the neutron-proton interactions and cross-shell excitations. However, the large uncertainty of the experimental data for the midshell nucleus Te-118 and the missing data for Te-116 make it difficult to pin down the general trend of the evolution of transition probabilities as a function of the neutron number. In this work, the lifetime of the yrast 2(+) state in Te-118 was measured, with the aim of reducing the uncertainty of the previous measurement. The result is tau(2+)=7.46(19) ps. In addition, the lifetime of the 4(+) state was measured to be tau(4+)=4.25(23) ps. The experimental transition rates are extracted from the measured lifetimes and compared with systematic large-scale shell-model calculations. The trend of the B(E2;0(+)-> 2(+)) values in the midshell area is in good agreement with the calculations and the calculated B-4/2 ratio provide evidence for Te-118 as a near perfect harmonic vibrator.

  • 5. Diener, Peter
    et al.
    Rosswog, Stephan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Torsello, Francesco
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi. Stockholms universitet, Naturvetenskapliga fakulteten, Oskar Klein-centrum för kosmopartikelfysik (OKC).
    Simulating neutron star mergers with the Lagrangian Numerical Relativity code SPHINCS _ BSSN2022Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 58, nr 4, artikel-id 74Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present the first neutron star merger simulations performed with the newly developed Numerical Relativity code SPHINCS_BSSN. This code evolves the spacetime on a mesh using the BSSN formulation, but matter is evolved via Lagrangian particles according to a high-accuracy version of general-relativistic Smooth Particle Hydrodynamics (SPH). Our code contains a number of new methodological elements compared to other Numerical Relativity codes. The main focus here is on the new elements that were introduced to model neutron star mergers. These include (a) a refinement (fixed in time) of the spacetime-mesh, (b) corresponding changes in the particle–mesh mapping algorithm and (c) a novel way to construct SPH initial data for binary systems via the recently developed “Artificial Pressure Method.” This latter method makes use of the spectral initial data produced by the library LORENE, and is implemented in a new code called SPHINCS_ID. While our main focus is on introducing these new methodological elements and documenting the current status of SPHINCS_BSSN, we also show as a first application a set of neutron star merger simulations employing “soft” (Γ=2.00Γ=2.00) and “stiff” (Γ=2.75Γ=2.75) polytropic equations of state.

  • 6.
    Makonyi, Karoly
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Preston, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Wölbing, Dirk
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR2016Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 52, nr 10, artikel-id 325Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Simulation results for future measurements of electromagnetic proton form factors at PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel (p) over barp -> e(+)e(-) is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e. (p) over barp -> pi(+)pi(-), is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance.

  • 7.
    Makonyi, Karoly
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    von Würtemberg, Klas Marcks
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Experimental access to Transition Distribution Amplitudes with the PANDA experiment at FAIR2015Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 51, nr 8, artikel-id 107Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Baryon-to-meson Transition Distribution Amplitudes (TDAs) encoding valuable new information on hadron structure appear as building blocks in the collinear factorized description for several types of hard exclusive reactions. In this paper, we address the possibility of accessing nucleon-to-pion (pi N) TDAs from (p) over barp -> e(+)e(-)pi(0) reaction with the future PANDA detector at the FAIR facility. At high center-of-mass energy and high invariant mass squared of the lepton pair q(2), the amplitude of the signal channel (p) over barp -> e(+)e(-)pi(0) admits a QCD factorized description in terms of pi N TDAs and nucleon Distribution Amplitudes (DAs) in the forward aid backward kinematic regimes. Assuming the validity of this factorized description, we perform feasibility studies for measuring (p) over barp -> e(+)e(-)pi(0) with the PANDA detector. Detailed simulations on signal reconstruction efficiency as well as on rejection of the most severe background channel, i.e. (p) over barp -> pi(+)pi(-)pi(0) were performed for the center-of-mass energy squared s = 5 GeV2 and s = 10 GeV2, in the kinematic regions 3.0 < q(2) < 4.3 GeV2 and 5 < q(2) < 9 GeV2, respectively, with a neutral pion scattered in the forward or backward cone vertical bar cos theta(pi 0)vertical bar > 0.5 in the proton-antiproton center-of-mass frame. Results of the simulation show that the particle identification capabilities of the PANDA detector will allow to achieve a background rejection factor of 5 . 10(7) (1 . 10(7)) at low (high) q(2) for s = 5 GeV2, and of 1 . 10(8) (6 . 10(6)) at low (high) q(2) for s = 10 GeV2, while keeping the signal reconstruction efficiency at around 40%. At both energies, a clean lepton signal can be reconstructed with the expected statistics corresponding to 2 of integrated luminosity. The cross sections obtained from the simulations are used to show that a test of QCD collinear factorization can be done at the lowest order by measuring scaling laws and angular distributions. The future measurement of the signal channel cross section with PANDA will provide a new test of the perturbative QCD description of a novel class of hard exclusive reactions and will open the possibility of experimentally accessing pi N TDAs.

  • 8.
    Makonyi, Karoly
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    von Wurtemberg, K. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Technical design report for the PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker2013Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 49, nr 2, s. 25-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole PANDA scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.

  • 9.
    Makonyi, Karolyn
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Preston, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Wölbing, Dirk
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Precision resonance energy scans with the PANDA experiment at FAIR: Sensitivity study for width and line shape measurements of the X(3872)2019Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 55, nr 3, artikel-id 42Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper summarises a comprehensive Monte Carlo simulation study for precision resonance energy scan measurements. Apart from the proof of principle for natural width and line shape measurements of very narrow resonances with PANDA, the achievable sensitivities are quantified for the concrete example of the charmonium-like X(3872) state discussed to be exotic, and for a larger parameter space of various assumed signal cross-sections, input widths and luminosity combinations. PANDA is the only experiment that will be able to perform precision resonance energy scans of such narrow states with quantum numbers of spin and parities that differ from JPC=1--.

  • 10.
    Preston, Markus
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Wölbing, Dirk
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Study of excited Xi baryons with the (P)over-barANDA detector2021Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 57, nr 4, artikel-id 149Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The study of baryon excitation spectra provides insight into the inner structure of baryons. So far, most of the world-wide efforts have been directed towards N * and Delta spectroscopy. Nevertheless, the study of the double and triple strange baryon spectrum provides independent information to the N * and Delta spectra. The future antiproton experiment (P) over bar ANDA will provide direct access to final states containing a (Xi) over bar Xi pair, for which production cross sections up to mu b are expected in (p) over barp reactions. With a luminosity of L = 10(31) cm(-2) s(-1) in the first phase of the experiment, the expected cross sections correspond to a production rate of similar to 10(6) events/day. With a nearly 4 pi detector acceptance, (P) over bar ANDA will thus be a hyperon factory. In this study, reactions of the type (p) over barp -> (Xi) over bar (+)Xi*(-) as well as (p) over barp -> (Xi) over bar*(+)Xi(-) with various decay modes are investigated. For the exclusive reconstruction of the signal events a full decay tree fit is used, resulting in reconstruction efficiencies between 3 and 5%. This allows high statistics data to be collected within a few weeks of data taking.

  • 11. Schonning, K.
    et al.
    Bargholtz, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Bashkanov, M.
    Berlowski, M.
    Bogoslawsky, D.
    Calen, H.
    Clement, H.
    Demiroers, L.
    Ekstrom, C.
    Fransson, K.
    Gerén, Linda
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Gustafsson, L.
    Hoistad, B.
    Ivanov, G.
    Jacewicz, M.
    Jiganov, E.
    Johansson, T.
    Keleta, S.
    Khakimova, O.
    Kren, F.
    Kullander, S.
    Kupsc, A.
    Kuzmin, A.
    Lindberg, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Marciniewski, P.
    Morosov, B.
    Oelert, W.
    Pauly, C.
    Petren, H.
    Petukhov, Y.
    Povtorejko, A.
    Scobel, W.
    Shafigullin, R.
    Shwartz, B.
    Skorodko, T.
    Sopov, V.
    Stepaniak, J.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Engblom, Pia Thörngren
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tikhomirov, V.
    Turowiecki, A.
    Wagner, G. J.
    Wolke, M.
    Zabierowski, J.
    Zartova, Irina
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Zlomanczuk, J.
    Production of eta and 3 pi mesons in the pd -> (HeX)-He-3 reaction at 1360 and 1450 MeV2010Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 45, nr 1, s. 11-21Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The cross-sections of the pd -> He-3 eta, pd -> He-3 pi(0)pi(0)pi(0) and pd -> He-3 pi(+)pi(-)pi(0) reactions have been measured at the beam kinetic energies T-p = 1360 MeV and T-p = 1450 MeV using the CELSIUS/WASA detector setup. At both energies, the differential cross-section d sigma/d Omega of the eta meson in the pd -> He-3 eta reaction shows a strong forward-backward asymmetry in the CMS. The ratio between the pd -> He-3 pi(+)pi(-)pi(0) and pd -> He-3 pi(0)pi(0)pi(0) cross-sections has been analysed in terms of isospin amplitudes. The reconstructed invariant-mass distributions of the pi pi, He-3 pi and (3)He2 pi systems provide hints on the role of nucleon resonances in the 3 pi production process.

  • 12. Skorodko, T.
    et al.
    Bashkanov, M.
    Bogoslawsky, D.
    Calen, H.
    Clement, H.
    Doroshkevich, E.
    Demiroers, L.
    Ekstrom, C.
    Fransson, K.
    Gustafsson, L.
    Hoistad, B.
    Ivanov, G.
    Jacewicz, M.
    Jiganov, E.
    Johansson, T.
    Khakimova, O.
    Keleta, S.
    Koch, I.
    Kren, F.
    Kullander, S.
    Kupsc, A.
    Marciniewski, P.
    Meier, R.
    Morosov, B.
    Pauly, C.
    Petren, H.
    Petukhov, Y.
    Povtorejko, A.
    Ruber, R. J. M. Y.
    Schonning, K.
    Scobel, W.
    Shwartz, B.
    Stepaniak, J.
    Thorngren-Engblom, P.
    Tikhomirov, V.
    Wagner, G. J.
    Wolke, M.
    Yamamoto, A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Zabierowski, J.
    Zlomanczuk, J.
    Exclusive measurement of the pp -> nn pi(+)pi(+) reaction at 1.1 GeV2011Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 47, nr 9, s. 108-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    First exclusive data for the pp -> nnp(+)pi(+) reaction have been obtained at CELSIUS with the WASA detector setup at a beam energy of T(p) - 1.1 GeV. Total and differential cross-sections disagree with theoretical calculations, which predict the Delta Delta excitation to be the dominant process at this beam energy. Instead, the data require the excitation of one of the nucleons to a higher-lying Delta state, preferably the Delta(1600)P(33), to be the leading process.

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