Swedish Nuclear Physicist's Meeting 2021

Europe/Zurich
Department of Physics, GD-Lecture Hall (Chalmers University of Technology)

Department of Physics, GD-Lecture Hall

Chalmers University of Technology

Chalmers Tvärgata 5
Andreas Ekström (Chalmers Tekniska Högskola), Andreas Heinz (Chalmers University of Technology), Per-Erik Tegnér (Stockholms Universitet)
Description

Sektionen för kärnfysik inom Svenska Fysikersamfundet (SFS-KF) tillsammans med SFAIR-konsortiet anordnar, vid Chalmers tekniska högskola, årets möte onsdag - fredag, 27-29 oktober.

Självklart strävar vi efter att kunna genomföra ett säkert möte på plats i Göteborg och hoppas därför att du vill delta fysiskt. Vi strävar också efter att kunna streama alla föredrag live och erbjuda fjärrpresentation via Zoom.

Vi räknar med att mötet börjar med registrering på onsdag 27 oktober kl 10.30, och att det vetenskapliga programmet startar med första föredraget kl 13.15 samma dag. Inbjudna föredrag är 35' (30'+5'), och övriga bidrag 25' (20'+5') eller 20' (15'+5').

Mötet kommer att innehålla presentationer av aktuell kärnfysikforskning som grupper vid svenska lärosäten är engagerade i. Presentationerna ges i form av översiktsföredrag av inbjudna föreläsare samt kortare bidrag. SFS-KF:s styrelse inbjuder kärnfysikgrupperna i Sverige att föreslå korta presentationer till mötet. Föredrag av doktorander och unga forskare kommer att prioriteras.

Registrering stänger: 12 oktober

Abstract inskick stänger: 12 oktober

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The nuclear physics section of the Swedish Physical Society (SFS-KF) and the Swedish FAIR-consortium organize the Swedish Nuclear Physicist's Meeting meeting at Chalmers unversity of technology this year, Wednesday - Friday, 27-29 oktober.

We strive for a safe, in-person event, and we hope that you will attend the meeting in-person at Chalmers. We also strive to provide a live stream of all talks and accommodate remote presentations via Zoom.

We expect the meeting to start with a registration at 10.30 am on Wednesday October 27, and that the first talk of the scientific programme begins at 1.15 pm. Invited talks are 35' (30'+5'), and contributed talks are 25' (20'+5') or 20' (15'+5').

The meeting will feature several invited speakers covering hot and interesting topics in nuclear physics. 

We are fortunate to have attracted the following distinguished invited speakers:

  • Helena Albers, GSI Darmstadt
  • Sonia Bacca, Johannes Gutenberg Universität Mainz
  • Andrea Jedele, GSI Darmstadt
  • Johan Messchendorp, KVI Groningen
  • Jonathan Wilson, Université Paris-Saclay
     

Swedish research groups in nuclear physics are kindly invited to suggest short presentations at the meeting. Ph.D. students and young scientists will be given priority.

Registration until: 12 October

Abstract submission until: 12 October

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We are generously sponsored by:

  • The Royal Swedish Academy of Sciences: The Nobel Committee for Physics
  • Gammadata
  • The Department of Physics at Chalmers
  • The Division of Subatomic, High Energy and Plasma Physics, at Chalmers
Participants
  • Alexandra Roussou
  • Ali Al-Adili
  • Ana Maria Gomez
  • Andrea Idini
  • Andrea Jedele
  • Andreas Ekström
  • Andreas Heinz
  • Anna Kawecka
  • Bjorn Jonson
  • Chong Qi
  • Christian Forssén
  • Claes Fahlander
  • Daniel Cox
  • Dirk Rudolph
  • Dorthea Gjestvang
  • Emanuel Ydrefors
  • Gandharva Appagere
  • Göran Nyman
  • Helena Albers
  • Håkan Johansson
  • Isak Svensson
  • Jana Rieger
  • Jana Vasiljević
  • Jimmy Ljungberg
  • jimmy rotureau
  • Joakim Cederkall
  • Johan Boström
  • Johan Messchendorp
  • Johannes Hansson
  • Jonathan Wilson
  • Karin Schönning
  • Luis Gerardo Sarmiento Pico
  • Maria Doncel Monasterio
  • Maria Vittoria Managlia
  • Martin Albertsson
  • Matthias Holl
  • Michael Papenbrock
  • Oliver Thim
  • Patrik Adlarson
  • Per-Erik Tegnér
  • Sean Miller
  • Sonia Bacca
  • Sven Åberg
  • Thomas Nilsson
  • Tord Johansson
  • Viktor Thorén
  • Wei Zhang
  • Weiguang Jiang
  • Yuliia Hrabar
  • Zhihao Gao
  • Örjan Skeppstedt
    • 10:30 11:30
      Registration 1h Department of Physics, GD-Lecture Hall

      Department of Physics, GD-Lecture Hall

      Chalmers University of Technology

      Chalmers Tvärgata 5
    • 11:30 13:15
      Lunch 1h 45m
    • 13:15 15:00
      Wednesday: Afternoon I Department of Physics, GD-Lecture Hall

      Department of Physics, GD-Lecture Hall

      Chalmers University of Technology

      Chalmers Tvärgata 5
      Convener: Ali Al-Adili
      • 13:15
        Welcome 10m
        Speaker: Andreas Ekström
      • 13:25
        Angular momentum generation in nuclear fission 35m

        When a heavy atomic nucleus fissions, the resulting fragments are observed to emerge spinning; this phenomenon has been an outstanding mystery in nuclear physics for over 40 years. The internal generation of around 6-7 units of angular momentum in each fragment is particularly puzzling for systems which start with zero, or almost zero, spin. There are currently no experimental observations which enable decisive discrimination between the many competing theories for the angular momentum generation mechanism. Nevertheless, the present consensus is that excitation of collective vibrational modes generate the intrinsic spin before the nucleus splits (pre-scission).
        We present comprehensive and unique new data on fission fragment spins from gamma-ray spectroscopy experiments carried out at the ALTO facility of IJC lab in Orsay on three fissioning systems 232Th(n,f), 238U(n,f), and 252Cf(SF). The ν-ball gamma-ray spectrometer was coupled to the LICORNE neutron source to perform precision spectroscopy of fast-neutron-induced fission in an experimental campaign that lasted 7 weeks. The experimental results presented will be used to draw important conclusions on the intrinsic spin generation mechanism in nuclear fission. This new information is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the γ-ray heating problem in nuclear reactors, for the study of the structure of neutron-rich isotopes, and for the synthesis and stability of super-heavy elements.

        Speaker: Dr Jonathan Wilson
      • 14:00
        Excitation energy dependence of prompt fission $\gamma$-ray emission from $^{241}Pu^*$ 20m

        Prompt fission $\gamma$ rays (PFGs) resulting from the ${^{240}Pu}$($d$,$p$f) reaction have been measured as a function of fissioning nucleus excitation energy $E_\text{x}$ at the Oslo Cyclotron Laboratory. We study the average total PFG multiplicity per fission, the average total PFG energy released per fission, and the average PFG energy. No significant changes in these characteristics are observed over the range $5.75 < E_\text{x} < 8.25$ MeV. The physical implications of this result are discussed. The experimental results are compared to simulations conducted using the computational fission model FREYA. We find that FREYA reproduces the experimental PFG characteristics within $8\%$ deviation across the $E_\text{x}$ range studied. Previous excitation energy-dependent PFG measurements conducted below the second-chance fission threshold have large uncertainties, but are generally in agreement with our results within a $2\sigma$ confidence interval. However, both a published parameterization of the PFG energy dependence and the most recent PFG evaluation included in ENDF/B-VIII.0 were found to poorly describe the PFG excitation-energy dependence observed in this and previous experiments.

        Speaker: Dorthea Gjestvang (University of Oslo)
      • 14:20
        Benchmark of a simulation of the ion guide for neutron-induced fission products 20m

        Independent yield distributions of high-energy neutron-induced fission is of importance to achieve a good understanding of the fission process. Further more, these data also plays an important role in the development of Generation IV nuclear reactors. While the mass and charge yield distributions of thermal neutron-induced fission is well known, there is a lack of experiment data for high-energy neutron-induced fission.

        To facilitate such measurements, a dedicated ion guide and a proton-to-neutron converter were developed and put to use in experiments at the IGISOL facility in Jyväskylä. In parallel, a simulation model based on GEANT4, MCNPX, and GEF was developed to optimize the setup. To benchmark the simulation model, foils located in the ion guide during the irradiation were taken out from the ion guide and analysed using $\gamma$-ray spectrometry. The measurements were conducted after the beam was turned off and after several days of cooling using a HPGe detector under shielding. Based on the identified $\gamma$-ray transitions, the productions of corresponding fission products and neutron activation products could be calculated and used to benchmark the transportation and collection of fission products in the simulations, as well as the simulated neutron flux. The conclusion is that the transportation of fission products in the helium gas simulated by GEANT4 agrees to the measurement very well, while the transportation of fission products in the uranium targets deviates by about 10~%. Furthermore, the neutron flux at high-energy seems to be overestimated by about 40~%.

        From the benchmark, it has been proven that the predictive power of the model is remarkable and sufficient for the purpose of modeling the ion guide. Furthermore, the parameters involved in the simulations, such as neutron production, distance between the neutron source and the ion guide, the volume of the ion guide and so on, play an important role in the optimization of the setup. However the lower fission rate than expected suggests the optimization on these parameters may not be enough to achieve sufficient intensity of fission products, especially for nuclei far from the line of stability. To further improve the setup, we are considering to implement electric field guidance, similar to the RF structure of the CARIBU gas catcher~[1], to more efficiently collect the fission products.

        [1] G. Savard, A.F. Levand, and B.J. Zabransky. The CARIBU gas catcher".
        In: Nucl. Inst. Meth. B 376 (2016), pp. 246-250.

        Speaker: Gao Zhihao
      • 14:40
        Determination of the Plasma Delay Time in PIPS detectors for fission fragments with the LOHENGRIN spectrometer 20m

        The particle spectrometer VERDI (VElocity foR Direct particle Identification) allows high-precision measurements of fission fragment (FF) yield by using the so-called 2E-2v technique. The spectrometer allows the determination of the FF mass, both before and after neutron emission, by means of a time-of-flight (ToF) and energy measurement. VERDI consists of two arms with 16 Silicon PIPS (Passivated Implanted Planar Silicon) detectors and a Micro Channel Plate (MCP) each. The MCPs provide the start signal for the ToF measurement, and the Si detectors are used both for energy detection and as a stop signal. In silicon detectors, the signal amplitude and shape get affected by the formation of a plasma from the interaction between the heavy ions and the detector material, which entails both, a signal loss and a signal delay. The amplitude defect and the time delay, are referred to as Pulse Height Defect (PHD) and Plasma Delay Time (PDT), respectively. If not accounted for, they can render faulty fission-neutron correlations, which makes PHD and PDT corrections imperative.

        A characterization of the PDT in the silicon detectors used in VERDI was performed at the LOHENGRIN recoil separator of the Institut Laue Langevin, for a wide range of energies and masses, $E$ $\sim$ 40-110 MeV and $A$ $\sim$ 80-160 u, respectively. With LOHENGRIN, characteristic FFs from $^{239}$Pu(n,f) were selected based on their A/q and E/q ratios. A unique collaboration allowed the utilization of a MCP detector from the STEFF spectrometer [1] and 6 silicon detectors from VERDI. The measured ToF, between the MCP and Si was compared to the true ToF derived from LOHENGRIN. The signals were recorded in a digital acquisition system to completely exploit the offline analysis capabilities. All the PIPS detectors were fully characterized to study their individual response to the PDT effect. The data will provide a calibration procedure in which the PDT contribution is calculated relative to alpha particles and protons. The achieved combined timing and energy resolutions of our experimental setup are around 160 ps and 0.1 MeV (FWHM), respectively.

        The first preliminary results from the analysis will be presented, where the PDT is estimated both in absolute terms and relative to alpha particles.

        [1] I. Tsekhanovich, J.A. Dare, A. G. Smith, et. al. A novel 2v2e spectrometer in Manchester: new development in identification of Fission Fragments Seminar on Fission pp 189-196 (2008). https://doi.org/10.1142/9789812791061_0018

        Speaker: A. Gómez (Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden)
    • 15:00 15:30
      Coffe 30m
    • 15:30 16:55
      Wednesday: Afternoon II Department of Physics, GD-Lecture Hall

      Department of Physics, GD-Lecture Hall

      Chalmers University of Technology

      Chalmers Tvärgata 5
      Convener: Chong Qi
      • 15:30
        Excitation-energy dependence of the prompt fission neutron-multiplicity in the fission of Uranium 235 25m

        The neutron emission is an important signature of the energy sharing in the nuclear fission process. Highly excited, neutron-rich nuclei release their energy by emitting prompt neutrons and γ-rays. Improved determination of particle-emission characteristics enhances the understanding of fission dynamics. The nuclear data libraries lack data which are crucial for these areas, especially the evolution of nuclear observables as a function of excitation energy. For instance, the change in the prompt neutron multiplicity, \bar{ν}(A), as a function of excitation energy is one of many open questions, which leads to divergences between fission models. Earlier data, based on indirect neutron measurements, suggest that only the heavy fission fragments exhibit an increased \bar{ν}(A). This needs to be systematically verified as it has bearings on fission modeling and has an impact on calculation codes for reactors, nuclear waste-management and other applications.

        We report on a direct experimental determination of the so-called sawtooth shape, \bar{ν}(A), as a function of the nuclear excitation energy. Fission fragment from the 235U(n,f) reaction were measured, in coincidence to fission neutrons, at the MONNET accelerator of the EC-JRC-GEEL. Most existing literature data are a result of indirect measurements, by detecting the fission fragment velocities and energies. We performed a direct coincidence measurement by use of liquid scintillators and a Twin Frisch-grid ionization chamber. The experiments were conducted at thermal neutron energy and are now being performed at 5.5 MeV incident neutron energy. A fully digital data acquisition system was used which allowed detailed offline analysis on the raw signal traces.

        We will present \bar{ν}(A) and \bar{ν}(Total Kinetic Energy) for ^{235}U at thermal and discuss the preliminary data at 5.5 MeV incident neutron energy.

        Speaker: Ali Al-Adili
      • 15:55
        Rapid detection and localization of special nuclear materials 20m

        ABSTRACT
        We have developed a method for sensitive detection and localization of special nuclear materials (SNM) within the context of an organic scintillator based radiation portal monitor (RPM) prototype system. The method uses fast time and energy correlations between gamma-rays and neutrons from spontaneous fission, and may be used as an additional detection modality, besides single gamma-ray and neutron counting. The newly developed neutron-gamma emission tomography (NGET) technique make possible fast and precise localization of small amounts of SNMs. This novel technique addresses global security threats from terrorism and the proliferation of nuclear weapons. It is demonstrated within the framework of an RPM prototype system, but it can be adapted to different detection geometries and applications, such as nuclear security, public safety, nuclear accident scenarios and radiological surveying in various contexts. Results on the RPM detection capabilities and localization accuracy in different shielding scenarios will be presented.

        Speaker: Jana Vasiljević (KTH )
      • 16:15
        Per-trigger yield analysis of pions, kaons and protons in pp collisions at √s = 13 TeV registered by the ALICE experiment 20m

        Per-trigger yield analysis of pions, kaons and protons in pp collisions at √s = 13 TeV registered by the ALICE experiment

        Speaker: Anna Kawecka
      • 16:35
        Study of the 18O+12,13C fusion-evaporation reactions with the GARFIELD array 20m

        Study of the 18O+12,13C fusion-evaporation reactions with the GARFIELD array

        Speaker: Maria Vittoria Managlia
    • 17:00 17:45
      SFS-KF Annual Meeting Department of Physics, GD-Lecture Hall

      Department of Physics, GD-Lecture Hall

      Chalmers University of Technology

      Chalmers Tvärgata 5
      • 17:00
        SFS-KF Annual Meeting 45m
        Speaker: Andreas Ekström
    • 19:00 22:00
      Conference Dinner 3h Wijkanders Restaurant

      Wijkanders Restaurant

    • 09:30 11:45
      Thursday: Morning Department of Physics, GD-Lecture Hall

      Department of Physics, GD-Lecture Hall

      Chalmers University of Technology

      Chalmers Tvärgata 5
      Convener: Per-Erik Tegnér
      • 09:30
        PANDA@FAIR: subatomic physics with antiprotons 35m Department of Physics, GD-Lecture Hall

        Department of Physics, GD-Lecture Hall

        Chalmers University of Technology

        Chalmers Tvärgata 5

        PANDA@FAIR: subatomic physics with antiprotons

        Speaker: Johan Messchendorp (GSI)
      • 10:05
        Exploring the borders of the Island of Inversion: Unbound States in 29Ne 25m Department of Physics, GD-Lecture Hall

        Department of Physics, GD-Lecture Hall

        Chalmers University of Technology

        Chalmers Tvärgata 5

        Exploring the borders of the Island of Inversion: Unbound States in 29Ne

        Speaker: Matthias Holl
      • 10:30
        Coffee 30m
      • 11:00
        [zoom]Proton decay study of the exotic isotopes $^{116,117}$La 20m Department of Physics, GD-Lecture Hall

        Department of Physics, GD-Lecture Hall

        Chalmers University of Technology

        Chalmers Tvärgata 5

        Measurements of proton decay properties provide valuable spectroscopic information on the structure of nuclei far from stability. In this presentation, I will report the results of our decay-spectroscopy study about the extremely neutron-deficient Lanthanum isotopes $^{116,117}$La. These nuclei were produced at the Accelerator Laboratory of the University of Jyväskylä by employing fusion-evaporation reactions, using a $^{64}$Zn beam at 330 MeV to bombard a $^{58}$Ni target. In this experiment, the fusion products were separated in flight through the newly commissioned recoil mass separator MARA and implanted into a double-sided silicon strip detector. The proton decay of the ground state of $^{117}$La was remeasured and found to be consistent with previous studies. In addition, we observed a new proton decay line, most likely from the ground state of $^{116}$La.

        Speaker: Wei Zhang (KTH)
      • 11:25
        [zoom] Update from the Swedish Research Council on FAIR 20m Department of Physics, GD-Lecture Hall

        Department of Physics, GD-Lecture Hall

        Chalmers University of Technology

        Chalmers Tvärgata 5

        10 minutes presentation, 10 minutes discussion

        Speaker: Niklas Ottosson (Swedish Research Council)
    • 11:45 13:15
      Lunch 1h 30m
    • 13:15 14:55
      Thursday: Afternoon I Department of Physics, GD-Lecture Hall

      Department of Physics, GD-Lecture Hall

      Chalmers University of Technology

      Chalmers Tvärgata 5
      Convener: Andrea Idini
      • 13:15
        Electroweak properties of nuclei from first principles 35m

        Electroweak properties of nuclei from first principles

        Speaker: Prof. Sonia Bacca (Johannes Gutenberg University)
      • 13:50
        Renormalization of Chiral Effective Field Theory in the Nucleon-Nucleon Sector 20m

        Chiral effective field theory ($\chi$EFT) promises a link between the underlying theory of the strong nuclear force --- quantum chromodynamics (QCD) --- and nuclear forces. The $\chi$EFT of low energy nuclear physics is formally parameterized by an infinite number of interaction diagrams, with accompanying undetermined interaction strengths called low-energy constants. To get a predictive theory at each order in the $\chi$EFT a power-counting procedure must be established. A sound power-counting procedure is also necessary for ensuring RG invariant predictions. I will present preliminary results from a Bayesian analysis of an RG invariant formulation of $\chi$EFT at leading order. This talk will try to illuminate the strengths and challenges of the ab initio $\chi$EFT approach to nuclear forces and how it can be used to increase our knowledge about the physics of nuclear systems.

        Speaker: Oliver Thim (Chalmers)
      • 14:10
        Bayesian uncertainty quantification in chiral effective field theory 20m
        Speaker: Isak Svensson
      • 14:30
        Proton image and momentum distributions from light-front dynamics 25m

        Understanding the structure and dynamics of the proton constitute one of the most important challenges in hadron physics. As is well-known, quantities such as nucleon form factors enter calculations of cross sections for neutrino nucleus scattering. Additionally, the nuclear force is the remnant of the strong force with nucleons. It is thus important to understand the strong force between quarks and gluons in the non-perturbative domain.

        From the theoretical point of view, one of the challenges is to extract from Lattice QCD calculations, performed in Euclidean space, Minkowskian quantities such as the proton parton distribution function. Due to the inherent difficulties associated with the mapping of Euclidean quantities to the corresponding Minkowskian ones, it is advantageous to have a solution defined directly in Minkowski space for calculations of dynamical observables such as momentum distributions.

        In this contribution we present results for the proton calculated using a simple but dynamical model defined in Minkowski space [1]. Our starting point is the Bethe-Salpeter-Faddeev equation for a system of three spin-less bosons interacting through a contact interaction. Recently, the solution to this equation was studied in great detail by us in the papers [2, 3, 4]. In this work, the equation is solved in the valence approximation and the parameters of the model are set by comparing the calculated Dirac form factor with experimental data. The single- and double parton distributions of the proton are then computed. The proton image on the null plane in the space given by the transverse coordinates and the Ioffe times \tilde{x}_{1,2} is also studied, by performing numerically the Fourier transformation of the distribution amplitude.

        [1] E. Ydrefors and T. Frederico, arXiv:2108.02146 [hep-ph].

        [2] E. Ydrefors, J.H. Alvarenga Nogueira, V. Gigante, T. Frederico and V.A. Karmanov, Phys. Lett. B 770 (2017) 131.

        [3] E. Ydrefors, J.H. Alvarenga Nogueira, V.A. Karmanov and T. Frederico, Phys. Lett. B 791 (2019) 276.

        [4] E. Ydrefors, J.H. Alvarenga Nogueira, V.A. Karmanov and T. Frederico, Phys. Rev. D 101 (2020) 096018.

        Speaker: Emanuel Ydrefors (Instituto Tecnologico de Aeronautica)
    • 14:55 15:30
      Coffee 35m
    • 15:30 17:00
      Thursday: Afternoon II Department of Physics, GD-Lecture Hall

      Department of Physics, GD-Lecture Hall

      Chalmers University of Technology

      Chalmers Tvärgata 5
      Convener: Joakim Cederkäll
      • 15:30
        Decay Spectrsoscopy Along Flerovium Decay Chains 25m

        Decay Spectrsoscopy Along Flerovium Decay Chains

        Speaker: Dr Daniel Martin Cox (Lund University (SE))
      • 15:55
        An Anti-Compton Shield for the LUNDIUM Decay Station 20m

        An Anti-Compton Shield for the LUNDIUM Decay Station

        Speaker: Yuliia Hrabar (Lund University)
      • 16:15
        Towards microscopic optical potentials using effective Hamiltonians derived from DFT calculations 25m

        During this talk I will present some recent development for the computation of nucleon-nucleus  optical potentials
        using effective Hamiltonians constructed from a mapping of DFT's results. More precisely, I will focus on the challenge
        related to the accurate calculations of overlaps in Hartree-Fock-Bogoliubov based theories and present a recently-published formula (B. G. Carlsson and J. Rotureau  PRL 126 2021), which allows for precise and numerically stable computations in this context.

        Speaker: Dr Jimmy Rotureau
      • 16:40
        Beyond mean field calculations by mapping EDF's to an effectiv Hamiltonian 20m

        One powerful technique to go beyond the mean field calculations is the generator coordinate method (GCM). This method incorporate correlations between mean field configurations. However, using an energy density functional (EDF), which is density dependent, for the interaction will make the mixing of states not well defined. Also, the existing methods for the mixing can lead to singularities.

        To solve those issues, we present a method to map EDF's to an effective Hamiltonian. This can be used in the GCM in a straightforward way without the risk of running into singularities.

        Speaker: Jimmy Ljungberg
    • 09:00 11:30
      Friday: Morning Department of Physics, GD-Lecture Hall

      Department of Physics, GD-Lecture Hall

      Chalmers University of Technology

      Chalmers Tvärgata 5
      Convener: Karin Schönning
      • 09:00
        DESPEC Phase-0 Commissioning and Experiments 35m Department of Physics, GD-Lecture Hall

        Department of Physics, GD-Lecture Hall

        Chalmers University of Technology

        Chalmers Tvärgata 5

        DESPEC Phase-0 Commissioning and Experiments

        Speaker: Helena Albers (GSI Helmholtzzentrum für Schwerionenforschung GmbH(GSI))
      • 09:35
        Finding the $\Sigma^0$’s Dalitz Decay with PANDA@HADES 20m Department of Physics, GD-Lecture Hall

        Department of Physics, GD-Lecture Hall

        Chalmers University of Technology

        Chalmers Tvärgata 5

        It is still one of the most challenging questions in fundamental physics is how hadrons are build from quarks. One way to address this question is to study hyperons. Hyperons are similar to nucleons but contain one or several strange quarks. By studying the decays of the unstable hyperons, we can gather valuable information about their inner structure which is quantified by electromagnetic form factors. In particular by studying hyperon Dalitz decays, where a hyperon decays into a lighter hyperon and a virtual photon that produces an electron-positron pair, low-energy quantities such as the magnetic dipole moment are accessible. The $\Sigma^0$ is, while mostly decaying through photon emission, predicted to also decay via Dalitz decay.

        The Fair Phase-0 project PANDA@HADES provides the prerequisites for studying this. HADES is a spectrometer designed for the investigation of hadronic matter and specialized for the detection of electron-positron pairs. Recently the setup has been complemented by the PANDA forward tracking system which extends the acceptance for protons originating from hyperon decays in forward direction.

        A feasibility study of measuring the $\Sigma^0$ Dalitz decay will be presented here with the upgraded HADES setup that will take data in spring 2022.

        Speaker: Jana Rieger (Uppsala University (UU))
      • 09:55
        Coffee 35m
      • 10:30
        From massive stars to neutron-skins: physics in the R3B collaboration at GSI 35m Department of Physics, GD-Lecture Hall

        Department of Physics, GD-Lecture Hall

        Chalmers University of Technology

        Chalmers Tvärgata 5

        The Reactions with Relativistic Radioactive Beams (R3B) collaboration at GSI provides a versatile experimental setup using high efficiency and resolution detectors covering a large range of acceptance. The combination of the versatile experimental setup and the fragment separator (FRS) allow one to explore a wide range of physics using relativistic radioactive beams in inverse-kinematics. In 2021 alone, the physics explored ranged from characterizing fission reaction mechanisms and topography of neutron-deficient nuclei in the mass range of A=180-210 to constraining the density dependence of the equation of state using neutron-removal cross sections in tin isotopes to understanding the evolution of massive stars after the helium burning phase through Coulomb dissociation of O-16 into C-12 and He-4. I will be discussing the physics explored within the collaboration and how the experimental configuration allows this. If time permits, I will also discuss future experiments.

        Speaker: Andrea Jedele (TU-Darmstadt)
    • 11:30 13:00
      Lunch 1h 30m