59. International Winter Meeting on Nuclear Physics

Bormio, Italy

Bormio, Italy

Concettina Sfienti (Johannes Gutenberg-Universität Mainz), Laura Fabbietti (excellence cluster 'universe'), Pierre Capel (Université Libre de Bruxelles (ULB)), Wolfgang Kuehn (JLU Giessen)

Long-standing conference bringing together researchers and students from various fields of subatomic physics. The conference location is Bormio, a beautiful mountain resort in the Italian Alps.

The 59th edition of the Bormio conference will be held in person from January 23 to 27 2023. Such a format will unfortunately limit the total number of participants. The actual number of people will depend on the Covid-19 guidelines fixed by the Italian government for the region of Lombardia; as of today, that number would be limited to 40. In addition, for the safety of all attendants, we will take a series of health and safety measures to mitigate the risk of infection (a.o. mandatory requirement of vaccination or negative test). We apologise in advance for the inconvenience these rules may pose to you; we hope that such regulations will be eased for the celebrations of the 60th edition, in January 2024!

Bormio Organisers
    • Monday Morning
      Convener: Prof. Laura Fabbietti (TUM)
      • 1


      • 2
        Unravelling the phase structure of QCD at high μB with HADES

        The microscopic properties of the strong-interaction matter under extreme conditions of temperature and density is a topic of great current interest. Despite 18 orders of magnitude difference in system size and time, the conditions present in heavy-ion collisions share great overlap with the conditions of the strong-interaction matter in neutron-star mergers. The possibility to form and explore in the laboratory strong-interaction matter under extreme conditions is truly fascinating.
        In this talk I will focus on relevantobservables to study criticality, emissivity, vorticity and equation-of-state of baryon rich matter. New experimental results on the mechanisms of strangeness production, the emissivity of matter and the role of baryonic resonances herein will be discussed. The multi-differential representations of hadron and dilepton spectra, collective effects and particle correlations will be confronted with results of other experiments as well as with hitherto model calculations. The results obtained for heavy-ion collisions are confronted to studies of elementary reactions serving as a reference for medium effects.

        Speaker: Prof. Tatyana Galatyuk (Tu-Darmstadt)
      • 3
        LHCb and the Flavour Puzzle

        The Flavour puzzle is one the most intruiging mysteries in particle physics.
        Why does nature provide us with three generations of similar fundamental fermions according to the Standard Model scheme?
        In the talk we will examine selected results of the LHCb experiment, which tries to zoom in on this puzzle.

        Speaker: Marcel Merk (Nikhef)
      • 10:40 AM
        Coffee break
      • 4
        Synthesis of light nuclei in hadronic collisions

        Light-nuclei production yields in heavy-ion collisions are well described in the frameworkof Statistical Hadronization Models (SHM) but a thorough understanding of the underlying dynamics is still missing. In a complementary approach, synthesis of light nuclei can be modeled in terms of final state coalescence of nucleons. While yielding an equally good description in heavy-ion collisions, coalescence predictions are substantially different to those from SHM in small collision systems, in particular for the loosely bound hypertriton. This should allow a firm distinction of the different production scenarios. Comprehensive data on light nuclei production in pp and p-Pb collisions became recently available from the ALICE collaboration and will be presented in this talk.

        Alternatively, the dynamics of nuclear cluster formation may also be inferred from final-state momentum correlations of nucleons and light nuclei. A powerful framework for correlation analyses of final-state hadrons was developed in ALICE, yielding unique information on the characteristics of the hadron-emitting source and, more notable, on the mutual interaction between them. This so-called femtoscopy technique was recently applied to final-state momentum correlations between protons and deuterons, emerging from high-multiplicity pp collisions. The correlation results will be compared to predictions based on experimental scattering parameters and put into perspective with the available data on light nuclei and hypertriton production.

        Speaker: Harald Appelshäuser (Univ. Frankfurt)
      • 5
        Oxygen photo-disintegration as a tool for studying 12C(a,g) at astrophysical energies.

        Thermonuclear reactions that power the stars take place at different energies according to their respective stellar environments. Such energies are well below the Coulomb barrier and the respective cross-sections are extremely small, often below experimental reach. Modelling energy production in stars requires experimental data on cross-sections for low energies; these data are sparse. As a consequence extrapolations are made, with a large degree of unavoidable uncertainty. Of special interest are (p, gamma) and (alpha, gamma) reactions, in particular those that regulate the ratio of C and O and those that burn 18O and, therefore, regulate the ratio between 16O and 18O in the Universe. One of the benchmark reactions to be investigated in this work is the 12C(alpha,gamma)16O at energies down to 1 MeV in the centre-of-mass reference frame.
        A new active target detector (time-projection chamber - TPC) optimised for experiments with high-intensity gamma-ray beams was developed and built at the University of Warsaw [1] to study time-inverse (gamma,p) and (gamma, alpha) stellar reactions.
        The dectector uses a 3-coordinate planar electronic readout acting as virtual pixels, read-out by GET electronics with negligible dead-time for the reaction rates (incl. background) expected for the reactions of interest with the available high-intensity gamma beams. Moreover, it can work with pure CO2 gas at pressures as low as 80 mbar.
        The detector was employed in 2022 in a campaign of measurements at the High Intensity Gamma-Ray Source (HIgS) facility at the Triangle Universities Nuclear Laboratory (TUNL), Durham, NC, USA. The time-inverse photo-disintegration processes induced by high energy photons were studied, using a monochromatic gamma-ray beam at energies ranging from 8.51 to 13.9~MeV, well beyond the previously-established limit [2]. The beam interacted with the CO2 gas in the chamber, where the charged reaction products, namely 12C and alpha particles, were detected, and their momenta reconstructed in 3D. The principles of the experiment will be described, together with preliminary results. An outlook on future plans will be given.

        [1] M. Cwiok et al., Acta Phys. Pol. 49 (2018) 509.
        [2] R. Smith et al., Nature Comm. 12, 5920 (2021) and M. Gai, NPA10 contribution

        Speaker: Dr Chiara Mazzocchi (University of Warsaw)
    • Monday Afternoon
      • 6
        (Towards) Solving the puzzle of high temperature light (anti-)nuclei production in ultra-relativistic heavy ion collisions

        The creation of loosely bound light (anti-)(hyper-)nuclei in heavy ion collisions near the phase transition temperature (Tch≈155 MeV) has been a puzzling observation. We solve this puzzle by showing that the light cluster abundancies in heavy ion reactions stay approximately constant from chemical freeze-out to kinetic freeze-out. To this aim we develop an extensive network of coupled reaction rate equations including stable hadrons and hadronic resonances to describe the temporal evolution of the abundancies of light (anti-)(hyper-)nuclei in the late hadronic environment. It is demonstrated that the chemical equilibration of the light nuclei occurs on a very short timescale as a consequence of the strong production and dissociation processes. However, because of the partial chemical equilibrium of the stable hadrons the abundancies of the light nuclei stay nearly constant during the evolution and cooling of the hadronic phase. A quantitative analysis shows a nice agreement with experimental data of the ALICE collaboration on d, 3 He, HΛ3 , and 4 He yields for a very broad range of temperatures at T≲155 MeV.This solves the longstanding contradiction between the thermal fits and the late stage coalescence.

        Speaker: Carsten Greiner (Goethe University Frankfurt)
      • 7
        A novel hydrodynamic approach to heavy quarks in the quark-gluon plasma

        A hydrodynamic approach to the transport of heavy quarks in the quark-gluon plasma (QGP) is presented. We exploit the conservation of the number of heavy quark-antiquark pairs within the evolution of the plasma to construct causal second-order hydrodynamic equations of motion. The hydrodynamic transport coefficients associated to the heavy-quark diffusion current are then compared with the momentum-diffusion coefficients obtained in the standard Fokker-Planck formalism. The purpose of this work is to provide further insights on the level of thermalization of charm and bottom quarks inside the expanding QGP with a novel approach, which consists in investigating the relation between hydrodynamics and transport theory and determining if their matching is able to capture the complexity of the heavy-quark in-medium dynamics.

        Speaker: Federica Capellino (Physikalisches Institut Heidelberg)
      • 8
        Recent ALICE results on quarkonium production in nuclear collisions

        Quarkonium suppression has long been regarded as a potential probe of
        deconfinement in nucleus-nucleus collisions. Recently, the production of 𝐽/𝜓 via regeneration within the QGP or at the phase boundary has been identified as an important ingredient for the interpretation of quarkonium production results from lead-lead collisions at the Large Hadron Collider (LHC). Moreover, the study of the excited states, as 𝜓(2𝑆), could help in distinguishing between recombination models.
        On the other hand, quarkonium polarization could represent a valuable tool to investigate the properties of the QGP. In fact, beyond the known suppression and regeneration mechanisms, quarkonium can be polarized by the strong magnetic field, generated in the early stages of the collision, and by the angular momentum of the medium in non-central heavy-ion collisions.
        In this contribution, the latest quarkonium results in Pb-Pb collisions from ALICE will be presented and discussed. These include, among others, the nuclear modifications of (inclusive, prompt and non-prompt) 𝐽/𝜓 and 𝜓(2𝑆) production, as well as the 𝐽/𝜓 polarization. The results will be compared with available theoretical model calculations.

        Speaker: Luca Micheletti
      • 9
        Recent results from the Katrin experiment


        Speaker: Mr Christoph Koehler (TUM)
    • Tuesday Morning
      • 10
        First Result from the Muon g-2 Experiment at Fermilab

        The muon anomalous magnetic moment, 𝑎𝜇=(𝑔−2)/2, provides one of the most precise tests of the Standard Model allowing to discover signs of the presence of new particles and forces in the subatomic quantum fluctuations surrounding the muon.
        A previous experiment performed two decades ago at Brookhaven National Laboratory (BNL) has shown an intriguing discrepancy between the theoretical prediction and the experimental value.
        The E989 Muon 𝑔−2 Experiment at Fermilab aims to improve by four times the precision of the BNL experiment.
        In its recent publication E989 has presented the result of the analysis of the first year of data taking (2018), confirming the discrepancy observed at BNL with a comparable precision.
        The talk will describe the E989 experimental technique, with particular attention to the measurement of the muon spin precession frequency and of the magnetic field. The experimental errors will be discussed and the expected improvements, coming from the analysis of the already available new runs, presented.

        Speaker: Stefano Di Falco (INFN Pisa)
      • 11
        Constraining neutron-star matter with microscopic and macroscopic collisions.


        Speaker: Dr Wolfgang Trautmann (GSI)
      • 10:20 AM
        Coffee break
      • 12
        Femtoscopy for flavored hadron-hadron interactions

        I discuss femtoscopic studies of hadron-hadron interactions mainly from a theoretical point of view. Femtoscopy denotes studies using two-(or more- )particle momentum correlation functions, which are given by the convolution of the source function and the relative
        wave function squared. Thus when the source function is known, one can obtain information on the wave function including the interaction effects from the correlation function. The latter approach, femtoscopy for hadron-hadron interactions, has been in strong
        progress in recent years.
        Femtoscopy is extremely useful for the hadron pairs whose scattering experiment is unavailable. For example, there was no experimental information about the N$\Omega$ interaction, but femtoscopy confirmed the validity of the potential obtained by lattice QCD for the
        first time. For $K^-p$ and $\Lambda$p, scattering data exist but have been limited to high-momentum regions. Since the correlation function is sensitive to low energy scattering parameters such as the scattering range, the femtoscopy is powerful to obtain
        s-wave hadron-hadron interactions.
        In the talk, I first discuss the correlation functions of hadron pairs including strangeness. Femtoscopy has met great successes in hyperon-nucleon (YN) and kaon-nucleon (KN and $\bar{K}N$) interactions. Next, I discuss the relevance of the bound states. The source size dependence of the correlation function can be utilized to guess the existence of a bound state, and some of the bound states have been suggested by the correlation functions. Finally, some of the correlation functions seem to require updates of theoretically proposed hadron-hadron interactions.

        Speaker: Dr Akira Ohnishi (Yukawa Institute, Kyoto University)
      • 13
        The EIC Canada Collaboration

        The Electron−Ion Collider is a major new facility scheduled to be built at Brookhaven National Laboratory on Long Island, NY, by the US Department of Energy. Polarized electrons will collide with polarized protons, light ions, and heavy nuclei at luminosities far beyond what is presently available, with the goal of answering fundamental questions central to nuclear physics today. Canadian subatomic physicists have participated extensively in the planning of this new laboratory and have chartered a multi−institutional EIC Canada Collaboration to coordinate participation. This talk will give a brief summary of the proposed facility and the some of the physics topics we plan to study.

        Speaker: David Hornidge (Mount Allison University)
      • 14
        Measurement of the inelastic cross sections of antinuclei with ALICE and implications for indirect Dark Matter searches

        Antinuclei in cosmic rays are considered a unique probe for signals from exotic physics, such as WIMP Dark Matter annihilations. Indeed, these channels are characterised by a very low astrophysical background, which comes from antinuclei produced by high energy cosmic ray interaction with ordinary matter.
        In order to make quantitative predictions for antinuclei fluxes near earth, both the production and annihilation cross sections of antinuclei need to be accurately known down to low energies.
        In ultra relativistic pp, p-Pb and Pb-Pb collisions at the CERN LHC, matter and antimatter are abundantly produced in almost equal amounts, allowing us to study the production of antinuclei and measure their absorption in the detector material. The antinuclei absorption cross section is evaluated on the average ALICE material. Using this result, we then predict the transparency of our galaxy to ${^3\mathrm{\overline{He}}}$ from both dark matter annihilations and high energy cosmic ray collisions.
        In this talk we present the first measurements of the antideuteron and ${^3\mathrm{\overline{He}}}$ absorption cross section with ALICE and we discuss the implications of these results for indirect Dark Matter searches using cosmic antinuclei.

        Speaker: Stephan Koenigstorfer (Technical University Munich)
    • Tuesday Afternoon
      • 15
        Isospin effects on the nuclear equation of state

        In this contribution we investigate the nuclear dynamics and the nuclear equation of state (NEOS) by a detailed study of heavy-ion collisions at intermediate energies. Indeed, we explore the isospin transport phenomena occurring during the collision between the projectile and target having different isospin contents. In particular, two observables are investigated the isospin diffusion and isospin migration. The former is related to the nucleon exchange process between the projectile and target; the latest is related to the neutron migration towards the low density region in the neck formed at mid-rapidity. Both observables provide an important information on the density dependence of the symmetry energy term of the NEOS.
        We will report on the experiments 40,48Ca+40,48Ca at E/A=35 MeV performed at GANIL, where we coupled the VAMOS spectrometer with the 4 INDRA detector. The use of the high acceptance spectrometer is to measure the isotopic and velocity distributions of the projectile like fragment (PLF) with high resolution, and INDRA is used, to estimate the impact parameter and excitation energy by measuring all charged products emitted in coincidence with PLF.
        From these experiments we obtain a set of data that for the first time measure different isospin sensitive observables in the same reaction. In particular a direct detection of the PLF residue in coincidence with an extraction of information about the N/Z of mid-rapidity. The set of data is open to comparison to all transport models engaged to link data to the symmetry energy.

        Speaker: Abdou Chbihi (GANIL, CEA-DSM/CNRS-IN2P3)
      • 16
        The PUMA experiment: motivation, objectives and current status the apparatus

        The antiProton Unstable Matter Annihilation (PUMA) experiment at CERN aims at using antiprotons to probe the nucleonic composition of the nuclear-density tail in stable and exotic nuclei. Antiprotons annihilate with nucleons: the summed electric charge of the annihilation products will reveal the neutron-to-proton content of the nucleus' surface. This allows to investigate quantum phenomena like halos and neutron skins. PUMA is currently being built. In the proposed poster, the motivation and the objectives of PUMA will be detailed. Additionally, an overview of the current status of the installation of PUMA at the AD facility of CERN and of the main components of the apparatus itself will be given.

        Speaker: Clara Klink (TU Darmstadt/CERN)
      • 17
        Perturbative EFT-inspired model of core excitations in one neutron halo nuclei

        Halo nuclei are exotic nuclear structures found far from stability near the dripline. In standard reaction models, halo nuclei are described as simple two or three-body systems: an inert core with one or two weakly bound neutrons.
        However, some breakup data suggest that the structure of the core, and in particular its excitation to its excited states, can play a role in the dynamics of the reaction [1].
        In this talk, we propose a simple structure model to account for that effect in the case of the typical one-neutron halo nucleus 11Be. To improve our description of the 10Be core without resorting to a fully microscopic model that is numerically expensive, we use a collective one: the rigid rotor [2].
        We assume the core to be weakly deformed, which we treat at the first order of perturbations to account for its 2+ first excited state, and we add this degree of freedom to the halo effective field theory description of 11Be developed in [3].
        Our first results indicate that if the LECs of the model are fitted to reproduce the long-range part of the overlap wave function of the ground state of 11Be computed ab initio [4], a good agreement can also be obtained with the ab initio s1/2 phaseshifts for the 10Be-n scattering up to about 3 MeV in the continuum compared to 1 MeV in the simple model of [3]. This would provide a model of halo nuclei both simple and reliable that could be used in reaction calculations for breakup and/or transfer. Such an improved few-body description of 11Be
        would enable us to efficiently study the influence of core excitation in nuclear reactions. Moreover, since the LECs are fitted to the ab initio calculation [4], this would provide a clean test of its predictions.

        [1] R. de Diego, et al., Phys. Rev. C 95, 044611 (2017).
        [2] F.M. Nunes, et al., Nucl. Phys. A 596, 171 (1996).
        [3] P. Capel, et al., Phys. Rev. C 98, 034610 (2018).
        [4] A. Calci, et al., Phys. Rev. Lett. 117, 242501 (2016).

        Speaker: Live-Palm Kubushishi
      • 18
        Neutral meson production at AgAg@1.58 A GeV

        Relativistic nucleus-nucleus collisions offer a unique possibility for studying nuclear matter under the influence of high temperature and pressure. During the collision, a system of interacting nucleons, resonances, and mesons, called a hadronic fireball, is created.
        The Dielectron Spectrometer HADES operated at the SIS18 synchrotron of FAIR/GSI, Darmstadt provided new intriguing results on the production of electron pairs and strangeness from nucleus-nucleus collisions, as well as from reference elementary reactions, in the energy region of 1 - 2 A GeV. In 2019 HADES was complemented by a new electromagnetic calorimeter based on lead-glass modules, which allows to measure production of the $\pi^0$ and $\eta$ mesons via their two $\gamma$ decays. In this energy range, $\pi^0$ and $\eta$ mesons are the most abundantly produced mesons carrying information from the hadronic fireball. In addition, the knowledge of the neutral meson production is a mandatory prerequisite for the interpretation of dielectron data and at the same time almost no respective data are presently available for this energy range.
        Recent results on $\pi^0$ and $\eta$ production in Ag + Ag collisions at 1.58 A GeV with $14\times10^9$ collected events will be presented along with HADES experiment short overview. The yields, transverse momentum and rapidity distributions will be shown as well as first results for the neutral pion flow.

        Speaker: Alexandr Prozorov
      • 19
        Coalescence in MC generators and implications for cosmic ray studies

        Coalescence is one of the main models used to describe the formation of light (anti)nuclei. It is based on the hypothesis that two nucleons close in phase space can coalesce and form a nucleus. Coalescence has been successfully tested in hadron collisions at colliders, from small (pp collisions) to large systems (Au-Au collisions). However, in Monte Carlo simulations (anti)nuclear production is not described by event generators. A possible solution is given by the implementation of coalescence afterburners, which can describe nuclear production on an event-by-event basis. This idea would find application in astroparticle studies, allowing for the description of (anti)nuclear fluxes in cosmic rays, which are crucial for indirect Dark Matter searches. In this presentation, the implementation of event-by-event coalescence afterburners will be discussed, focusing on different approaches and on the comparison with the experimental results for different collision systems.

        Speaker: Dr Chiara Pinto (TU-Munich)
    • Wednesday Morning
      • 20
        Deblurring 3D Characteristics of Heavy-Ion Collisions

        As reaction plane direction in heavy-ion collisions can be determined only coarsely, any attempt to measure 3D differential distributions, including over azimuthal angle, will yield blurred results. Deblurring procedures, analogous to those in optics, are proposed to correct for the coarse reaction-plane procedures and, simultaneously, any instrumental inefficiencies, to arrive at 3D distributions tied to true reaction plane. The refined 3D picture of the collisions can yield better access to the physics than the current method of azimuthal moments.

        Speaker: Pawel Danielewicz (Michigan State University)
      • 21
        Recent Results from Belle II

        The talk will cover the most recent results from the Belle II experiment

        Speaker: Dr Giulia Casarosa (University of Pisa)
      • 10:20 AM
        Coffee break
      • 22
        Unveiling thThorium Isomer 229mTh: On the way towards a Nuclear Clock as novel Quantum Sensor

        Today’s most precise timekeeping is based on optical atomic clocks. However, those could potentially be outperformed by a nuclear clock, based on a nuclear transition in-stead of an atomic shell transition. Such a nuclear clock promises intriguing applica-tions in applied as well as fundamental physics, ranging from geodesy and seismolo-gy to the investigation of possible time variations of fundamental constants and the search for Dark Matter [1,2].
        Only one nuclear state is known so far that could drive a nuclear clock: the ‘Thorium Isomer 229mTh’, i.e. the isomeric first excited state of 229Th, representing the lowest nu-clear excitation so far reported in the whole landscape of nuclear isotopes. Since its first direct detection in 2016 [3], considerable progress could be achieved in character-izing the properties and decay parameters of this elusive nuclear excitation: the half-life of the neutral isomer was determined [4], the hyperfine structure was measured via collinear laser spectroscopy, providing information on nuclear moments and the nu-clear charge radius [5] and also the excitation energy of the isomer could be directly determined 8.28(17) eV [6].
        In a very recent experiment at CERN’s ISOLDE facility, the long-sought radiative decay of the Thorium isomer could be observed for the first time via implantation of ( decay-ing) 229Ac into a VUV transparent crystal and subsequent fluorescence detection in a VUV spectrometer. Thus, the excitation energy of 229mTh could be determined with un-precedented precision to 8.338(24) eV, corresponding to a wavelength of 148.71(42) nm [7]. This recent breakthrough opens the door towards a laser-driven control of the isomeric transition and thus to the development of an ultra-precise nuclear frequency standard.
        The talk will review recently completed, ongoing and planned activities towards this goal.
        [1] E. Peik et al., Quantum Sci. Technol. 6, 034002 (2021).
        [2] P.G. Thirolf, B. Seiferle, L. v.d. Wense, Annalen der Physik 531, 1800391 (2019).
        [3] L. v.d. Wense et al., Nature 533, 47-51 (2016).
        [4] B. Seiferle, L. v.d. Wense, P.G. Thirolf, Phys. Rev. Lett. 118, 042501 (2017).
        [5] J. Thielking et al., Nature 556, 321 (2018).
        [6] B. Seiferle et al., Nature 573, 243 (2019).
        [7] S. Kraemer et al., arXiv:2209:10276

        Speaker: Prof. Peter G. Thirolf (Ludwig-Maximilians-Universität München)
      • 23
        Novel radioisotopes for medical applications: the CERN MEDICIS project and beyond

        In nuclear medicine, radioisotopes are injected into a patient to perform functional imaging or targeted radionuclide therapy. However, only a handful of radioisotopes are used in this field, mostly limited by a supply-and-demand closed loop that does not leave room for innovation. At radioactive ion beam facilities, however, we can provide a wide catalogue of radioisotopes to support medical research and break that conundrum. At CERN, the MEDICIS facility (MEDical Isotopes Collected from ISolde) has been established and provides radioisotopes for medical research regularly since 2018. On the European landscape, many facilities have federated themselves as PRISMAP - The European Medical Radionuclides Programme to push this innovation even further. In this contribution, I shall present the added value of those novel radionuclides, the pathway to translational research, and the prospects brought by these new initiatives.

        Speaker: Prof. Thomas Cocolios (KU Leuven)
      • 24
        Toward an effective field theory for LHC jets

        Jet cross sections at high-energy colliders exhibit intricate patterns of logarithmically enhanced higher-order corrections. In particular, so-called non-global logarithms emerge from soft radiation emitted off energetic partons inside jets. While this is a single-logarithmic effect at lepton colliders, at hadron colliders phase factors in the amplitudes lead to double-logarithmic corrections starting at four-loop order. This effect was discovered a long time ago, but not much is known about the higher-order behavior of these terms and their process dependence. We derive, for the first time, the all-order structure of these ``super-leading logarithms'' for generic $2\to n$ scattering processes at hadron colliders and resum them in closed form. We show that due to a strong numerical enhancement these effects can be numerically of the same order as a typical one-loop correction, and their inclusion is important for many precision calculations of LHC cross sections.

        Speaker: Matthias Neubert (Johannes Gutenberg University Mainz)
    • Wednesday Afternoon
      • 25
        The 2H(p,gamma)3He reaction at BBN energies: implications in Cosmology, particle physics and theoretical nuclear physics

        The LUNA collaboration has recently completed the measurement of the D(p,γ)3He cross section at Big Bang Nucleosynthesis (BBN) energies with unprecedented precision. The study of this deuterium-burning process provides a precise determination of the universal baryon density Ωb, in excellent agreement with the value derived from CMB. The new data also provide a stringent constrain the possible existence of "dark radiation", i.e. the existence of relativistic particles not foreseen in the standard model, such as sterile neutrinos or hot axions [1,2]. Finally, the LUNA measurement provides an experimental footing for recent ab-initio calculations [3,4]. The implications in cosmology and particle physics are discussed in this talk. It will be also shown the good agreement of data with respect to recent ab initio calculation concerning the total and differential D(p,γ)3He cross section.

        [1] V. Mossa. et al.:
        "The baryon density of the Universe from an improved rate of deuterium burning".
        NATURE 587, 210 (2020).
        [2] E. Di Valentino et al.:
        "Probing nuclear rates with Planck and BICEP2".
        arXiv:1910.10459v1 [nucl-ex] (23 October 2019).
        [3] Pisa theoretical group:
        “Differential cross section of the 2H(p,gamma)3He using a chiral effective field theory approach”
        (in preparation)
        [4] LUNA Collaboration:
        “Measurement of the Differential cross section of the 2H(p,gamma)3He at 32 < Ecm[keV] < 263”
        (in preparation)

        Speaker: Dr Carlo Gustavino (INFN-Roma1)
      • 26
        Bottomonium physics at Belle II

        Bottomonium ($b\overline{b}$) spectroscopy offers excellent opportunities for insights on the behavior of QCD in the non-perturbative regime. In order to guide theorists through the difficult task of modeling non-perturbative QCD phenomena, the experimental measurement of masses, widths, and transition rates of $b\overline{b}$ states is crucial. Recent analyses of Belle and Belle II data samples unveiled unexpected results in this field, such as the observation of anomalous transition rates and of new states that challenge the conventional description of $b\overline{b}$ mesons. In particular, the newly observed state identified as $Y(10753)$ is generating a big interest among theorists concerning its interpretation. The $b\overline{b}$ spectroscopy is thus encouraging the birth of a variety of new theoretical models. The latter include the contribution of hadronic loops, or the existence of exotic states such as compact tetraquarks, hadrobottomonia and hybrids. Belle II has the unique opportunity to analyze the $19 \ fb^{-1}$ data sample collected with a scan near $\sqrt{s}=10.75 \ GeV$, in order to provide experimental results in this sector. The talk will thus be focused on the recent Belle II results with the scan data and related prospects.

        Speaker: Alessandro Boschetti (INFN and University of Turin)
      • 27
        The ITS3 upgrade of the ALICE Inner Tracking System

        During the LHC Long Shutdown 3 (LS3) foreseen in 2026-2028, the ALICE collaboration is planning to replace the innermost three layers of the presently installed Inner Tracking System with a novel vertex detector, called ITS3. This further upgrade will improve the efficiency and tracking capabilities of the ALICE detector, especially at low transverse momentum, opening extraordinary opportunities for several physics studies.
        To achieve that goal, the proposed ITS3 will consist of truly cylindrical layers made of wafer-scale, thin and flexible stitched CMOS pixel sensors, with the innermost layer positioned at only 18 mm radial distance from the interaction point. According to the detector design, the material budget will be lowered to an unprecedented value of 0.05%X0 per layer and the pointing resolution will be improved by a factor of two.
        In this contribution, the ITS3 project will be presented, starting from the motivations of building such a device, later discussing the detector layout and specifications, and concluding with some selected highlights of the achieved R&D results.

        Speaker: Prof. Paola La Rocca (INFN Catania)
      • 28
        Relativistic fluid dynamics of multiple conserved charges in heavy-ion collisions

        The strongly interacting matter created in high-energy heavy-ion collisions contains a multitude of conserved quantum charges, like the baryon number, strangeness, and electric charge. These conserved charges lead to coupled charge currents, e.g. a baryon diffusion current, strangeness current and electric charge current. In this talk, we briefly present a novel derivation of second-order relativistic dissipative fluid dynamics from the Boltzmann equation for multicomponent reactive mixtures with $N_{\text{spec}}$ particle species and with $N_q$ conserved charges. We will show and discuss the coupled-charge transport, the resulting separation of charge, and the implied baryon-electric or baryon-strangeness correlations in heavy-ion collisions, and argue that such effects may be relevant for programs at the future FAIR and NICA facilities, or for the discussion of the recent isobar run at RHIC.

        Speaker: Jan Fotakis (University of Frankfurt)
      • 29
        Investigating the possibility of leakage detection in water distribution using cosmic ray neutrons

        Water distribution systems can experience high levels of leakage, originating from different sources, such as deterioration due to aging of pipes and fittings, material defects, and corrosion [1]. In addition to causing financial losses and supply problems, leakages in treated water distribution also represent a risk for public health. Nowadays, several techniques for leak detection have been investigated, such as acoustics, based on the detection of the noise produced by a leak in pressurized pipes, thermography, looking for changes in the soil temperature, and time domain reflectometry, looking for changes in the effective dielectric permittivity of the soil. Several factors, including the environmental noise, the geometry and composition of the pipes, the soil composition, the presence of tarmac on ground, etc., can limit the use these techniques.
        We are investigating the possibility of using cosmic ray (CR) neutrons for the leakage detection in water distribution: fast and epithermal CR neutrons, penetrating the soil, can be thermalized, mainly by means of collisions with hydrogen atoms, and diffuse back into the atmosphere. As a result, the flux of low-energy neutrons above the soil is inversely correlated with the hydrogen content of the soil, and in turn with the presence of water [3]. This mechanism has already been investigated in other contexts such as agriculture [4], catchment hydrology [5], snow hydrology and more with encouraging results.
        In this talk, we present a feasibility study of the technique, based on Monte Carlo simulations, and an overview of the neutron detector, currently in late stage of development, which will be used for the first experimental measurements.


        [1] AWWA (1999), “Water Audits and Leak Detection”. Manual of Water Supply Practices No. M36, 2nd Edition, American Water Works Association, Denver, CO, 99 pages.

        [2] A. Cataldo et al. (2016), “Accuracy improvement in the TDR-based localization of water leaks”. Results in Physics, Volume 6, 594-598, https://doi.org/10.1016/j.rinp.2016.08.012.

        [3] M. Zreda et al. (2008), “Measuring soil moisture content non‐invasively at intermediate spatial scale using cosmic‐ray neutrons”, Geophysical research letters 35, 21.

        [4] C. Finkenbiner et al. (2019), “Integration of hydrogeophysical datasets and empirical orthogonal functions for improved irrigation water management”, Precision agriculture 20.1, 78-100.

        [5] B. Fersch et al. (2018), “Synergies for soil moisture retrieval across scales from airborne polarimetric SAR, cosmic ray neutron roving, and an in situ sensor network”, Water Resources Research 54.11, 9364-9383.

        Speaker: Davide Pagano (University of Brescia)
    • Thursday Morning
      • 30
        Tight Symmetry Energy Parameter Constraints from Neutron Skin Measurements

        Inferences of nuclear symmetry energy parameters from recent parity-violating neutron skin measurements of the neutron-rich nuclei Ca-48 and Pb-208 appear to be in tension not only with each other but also with values obtained from fitting either nuclear masses or neutron matter theory. By themselves, PREX I+II measurements of Pb-208 and CREX measurement of Ca-48 suggest $L\simeq110\pm36$ MeV and $L\simeq23\pm27$ MeV, respectively, to 68\% confidence. However, jointly satisfying both at 90\% confidence implies $L\simeq51\pm11$ MeV, nearly exactly the range suggested by either nuclear mass fitting or neutron matter theory. This small inferred parameter range is also consistent with nuclear dipole polarizability measurements as well as X-ray and gravitational wave observations of neutron stars.

        Speaker: JAMES LATTIMER (Stony Brook University)
      • 31
        Hadron physics with LHCb


        Speaker: Mikhail Mikhasenko (TUM)
      • 10:30 AM
        Coffee break
      • 32
        Charm quarks from production to hadronisation in heavy–ion collisions

        Given their large mass, charm quarks are recognised as powerful probes of the colour-deconfined state of the matter called quark–gluon plasma (QGP) created in high-energy heavy–ion collisions. They are mainly pro- duced in high-momentum transfer processes in shorter timescales compared to the QGP formation time, and they subsequently experience the full sys- tem evolution interacting with the medium constituents via elastic scatter- ings and radiative processes.
        The comparison of measurements of charm-hadron production and an- gular anisotropies with phenomenological model calculations provides im- portant constraints to the charm-quark diffusion coefficient Ds in the QGP. However, the experimental observables are modified by additional effects, such as the modification of the charm-quark hadronisation in presence of a deconfined medium and the rescattering in the hadronic phase. Hence, the- oretical models based on the charm-quark transport in a hydrodynamically expanding QGP requires to properly model also the in-medium hadronisa- tion and the participation to the hadronic phase.
        In this contribution, the most recent estimate of the Ds transport coeffi- cient will be presented. Moreover, the studies of charm-quark hadronisation, via the measurement of charm baryon and charm-strange meson production from pp to Pb–Pb collisions will be shown. Finally, the measurement of scat- tering parameters governing the residual strong interaction between charm hadrons and light hadrons via the femtoscopy technique in pp collisions, crucial to constrain the effect of the hadronic rescattering in heavy–ion col- lisions, will be discussed.

        Speaker: Dr Fabrizio Grosa (CERN)
      • 33
        Exotic mesons with functional methods

        We summarize recent results on exotic mesons determined in the framework of functional methods (Dyson-Schwinger and Bethe-Salpeter equations) in QCD.
        We cover results on glueballs and four-quark states as well as their mixing
        with conventional mesons in the light quark sector of QCD. In the charmoninum region we shed light on the internal structure of heavy-light four-quark states with hidden as well as open charm content.

        Speaker: Christian Fischer (JLU Giessen)
    • Thursday Afternoon
      • 34
        The surface Resistive Plate Counter: an RPC based on MPGD technology

        The Surface Resistive Plate Counter (sRPC) is a novel RPC based on surface resistivity electrodes, a completely different concept with respect to traditional RPCs that use electrodes characterized by volume resistivity.
        The electrodes of the sRPC exploit the well-established industrial Diamond-Like-Carbon (DLC) sputtering technology on thin (50µm) polyimide foils, already introduced in the manufacturing of the resistive MPGDs such as µ-RWELL and MicroMegas. The DLC foil is then glued on a 2mm thick float-glass, characterized by excellent planarity. In the baseline layout the DLC is connected to the HV by a single dot connection outside the active area. With this layout we measured an efficiency of 95-97% and a time resolution of ~1ns.
        In addition, exploiting the concept of the high density current evacuation scheme, first introduced for the µ-RWELL, we realized prototypes with high-rate electrodes by screen printing a conductive grid onto the DLC film. With such a high-rate layout, 7GΩ/square DLC resistivity and 10mm grounding-pitch, we measured a rate capability of about 1kHz/cm2 with X-ray, corresponding to a m.i.p. flux of about 3kHz/cm2. By lowering the DLC resistivity and optimizing the current evacuation scheme, a rate capability of the order of 10kHz/cm2 seems to be achievable.
        A DLC magnetron sputtering machine, co-funded by CERN and INFN, has been recently acquired and installed at the CERN EP-DT-Micro-Pattern-Technology Workshop. With this facility it will be possible to realize large area (up to 1.8x0.6 m2) DLC electrodes with a resistivity spanning over several orders of magnitude (0.01÷10 GΩ/square).
        This innovative technology could open the way towards cost-effective high-performance muon devices for applications in large HEP experiments for the future generation of high luminosity colliders. The possibility of exploiting the sRPC technology for thermal neutron detection, by replacing DLC with B4C sputtered electrodes, is under investigation for a possible use in Radiation Portal Monitor for homeland security purpose.

        Speaker: Giovanni Bencivenni (LNF-INFN)
      • 35
        Pixelised Resistive Micromegas for High-Rate Environment

        Following the development, studies and construction of the resistive Micromegas detectors for the ATLAS experiment at CERN, in recent years an R&D project has been conducted to consolidate resistive Micromegas technology for operations well beyond the current ones in HEP experiments, with the aim of a stable, reliable, and high gain operation up to particle rates above 1 MHz/cm2, on large surfaces. To achieve this goal, while maintaining a low occupancy on the readout elements, a configuration with small pads readout (only few mm2) has been adopted, which requires innovative solutions for the spark protection resistive scheme.
        Two main resistive patterns were investigated, expanding the scope of the developments made in previous projects. The main difference between the adopted technical solutions is that in one case (embedded resistors) the charge evacuates through independent pads in a pad patterned layout, while in the other case a continuous and uniform double DLC resistive layer has been adopted and the charge evacuates through vertical dot-connections, several mm apart. A detailed performance comparison will be reported, showing the optimisations and benefits of this latest configuration.
        More recently, moving towards a larger scale, a new detector with an active area of 400 cm2 has been built, implementing a double layer of DLC foils with a surface resistivity around 30 MOhm/square. The first results will be reported on rate capability, robustness, dependence on the irradiated area, tracking efficiency and energy and spatial resolution following laboratory measurements and the next tests at CERN SPS with high energy particle beams.
        With the proven high performance of this large area detector, and with the construction of even larger small-pad resistive micromegas next year, our R&D is reaching the goal of establishing the technology for future use under hard and high-rate employment in the field of particle physics and other applications.

        Speaker: Mauro Iodice
      • 36
        The $\mu$-Resistive WELL in HEP and beyond

        Since a first prototype in 2009 the $\mu$-Resistive WELL ($\mu$-RWELL) technology has been object of an interesting evolution that required huge efforts to achieve the final goal: a detector matching the time and space resolution of all the other MPGDs, simple to assembly and at the same time exhibiting a good robustness against discharges. This goal has been achieved thanks to the introduction of a resistive layer, made of Diamond-Like Carbon, below the amplification stage which geometry is inherited by the GEM technology. The resistive layer limits the rate capability of the detector, as it is subjected to local charging-up: it is then necessary to implement an effective charge evacuation scheme to level up the rate capability of this detector to the one of the classic MPGDs.
        A particular effort has been then dedicated on how to model the grounding network of the resistive stage to made the detector suitable for high-rate purposes, winking at HL-LHC experiments.
        The overview proposed is a ride through time, layout by layout: each validated by X-rays and m.i.p. irradiation, with an eye on the applications of both low-rate- and high-rate-oriented detectors. Indeed this technology is finding room in several experiments even beyond HEP (X17, CLAS12, TACTIC, uRANIA-V); while, inside the high energy physics community, the technology has been proposed for IDEA apparatus at FCC_ee and for the Run 5-6 upgrade of the muon stations of LHCb where the expected peak rate is of the order of 1 MHz/cm$^2$. Another innovative project is ongoing inside the HEP field: a hadron imaging calorimeter at high granularity for the muon collider apparatus, where the absorbers are interleaved by MicroMegas and $\mu$-RWELL.
        This R\&D finds its completeness with a Technological Transfer, started by LNF-DDG team, with ELTOS S.p.A: a company leader in PCB production; this factory of the $\mu$-RWELL core, later shipped to CERN for the final chemical treatment. Thanks to this collaboration we expect to significantly reduce the cost of each detector, in view of a mass production foreseen to cover several square meters in huge experiments.

        Speaker: Gianfranco Morello (Laboratori Nazionali di Frascati dell'INFN)
      • 37
        Prospects for searches for a stable double strange hexaquark at Belle II

        QCD-motivated models for hadrons predict a wide variety of multi-quark states beyond ordinary mesons and baryons, known as exotic states.
        The first observation of a heavy exotic state by Belle in 2003 has triggered a huge experimental effort, and the last 20 years have marked a turning point in the field.
        To date, states composed of four and five valence quark have been observed and their existence confirmed. The possible observation of six-quark states would give us further insight into understanding and describing the strong interaction.
        In particular, the search for a stable double strange hexaquark, which was put forward also as a dark matter candidate, is part of the Belle II physics program, and a fraction of the experiment data taking period is plan to be dedicated to run at the energy of the Υ(3𝑆) resonance, particularly well suited for searches for multiquark states with non-zero strangeness.
        This talk presents a feasibility study for the search for a stable double strange six-quark state 𝑆 produced in Υ(3𝑆) decays, with a focus on the obtained predictions for both existing and novel measurements.

        Speaker: Dr Bianca Scavino (Johannes Gutenberg University)
      • 38
        Measurement of 16O fragmentation cross sections on C target with the FOOT apparatus

        In particle therapy (PT) nuclear interactions of the beam with the patient’s body causes fragmentation of both the projectile and target nuclei. In treatments with protons, target fragmentation generates short range secondary particles, that may deposit a non-negligible dose in the entry channel. On the other hand, in treatments with ions, such as C or O, the main concern is long range fragments produced by projectile fragmentation, that release the dose in the healthy tissues. Fragmentation processes need to be taken into account when planning a PT treatment to keep the dose accuracy within the recommended 3\% of tolerance level. The evaluation of the impact that these processes have on the released dose is very limited from the lack of experimental data, especially for the fragmentation cross sections.The FOOT (FragmentatiOn Of Target) collaboration designed an experiment tomeasure the double differential cross section of nuclear fragmentation processes relevant for charged PT. The experiment is meant to investigate target fragmentation (mainly 12𝐶 and 16𝑂 nuclei) induced by 50÷200 MeV proton beams. The nuclear fragmentation cross section on hydrogen will be studied via an inverse kinematic approach, where 12𝐶 and 16𝑂 therapeutic beams collide on graphite and hydrocarbon targets. Increasing the beam energy to 400÷500 MeV/u also the projectile fragmentation of these beams, impinging on targets of interest for PT, will be explored. \In this contribution, an overview of the FOOT experiment, including the detector design and the expected performances will be discussed. In addition preliminary values of charge-changing cross-sections, obtained from a first test experiment with 400 MeV/u 16𝑂 impinging on a carbon target with a partial setup, will be presented.

        Speaker: Marco Toppi (infn)
    • Friday Morning
    • Friday Afternoon
      • 43
        Nonlinear diffusion of gluons

        Fast local thermalization of gluons and quarks characterizes the initial stages of relativistic heavy-ion collisions. For a theoretical description, effective weakly-coupled kinetic theories that rely on the quantum Boltzmann equation have been proposed and solved numerically. In the present work, I aim to account for the time evolution during the rapid equilibration of partons in a simplified model through a nonlinear diffusion equation for the occupation-number distributions in the full momentum range. It is shown that in case of constant transport coefficients, the equation can be solved analytically in closed form through a nonlinear transformation. The occupation-number distribution is then obtained via the logarithmic derivative of a generalized (time-dependent) partition function.

        Although the nonlinear boson diffusion equation (NBDE) for the thermalization of gluons had been proposed in [1], the analytical solution had initially been derived only for the free case. In order to obtain the Bose-Einstein distribution in the stationary limit, however, one has to consider the boundary condition [2] at the singularity p=\mu with the chemical potential \mu<0 for number-conserving elastic gluon scatterings, and \mu=0 for inelastic scatterings, which are essential for the thermalization. It is shown that analytical solutions of the NBDE can still be obtained [3].

        The model is applied to the equilibration of gluons in heavy-ion collisions at LHC energies where initial central temperatures of 500-600 MeV are reached during local thermalization. Equilibrium is attained through the nonlinear evolution of the distribution functions at short times t<<1 fm/c in the infrared, whereas it takes more time in the large-momentum region to attain the Maxwell-Boltzmann tail of the distribution function. Thermalization in the IR occurs much faster through inelastic as compared to elastic gluon scatterings, thus preventing the formation of a gluon condensate through number-conserving elastic collisions. These results are consistent with QCD-based numerical findings in [4].

        [1] Wolschin, G.: Equilibration in ?finite Bose systems. Physica A 499, 1 (2018).
        [2] Wolschin, G.: Local thermalization of gluons in a nonlinear model. Nonlin. Phenom. Complex Syst. 23, 72 (2020).
        [3] Wolschin, G.: Nonlinear diffusion of gluons, in preparation.
        [4] Blaizot, J.P., Liao, J., Mehtar-Tani, Y.: The thermalization of soft modes in non-expanding isotropic quark gluon plasmas. Nucl. Phys. A 961, 37 (2017).

        Speaker: Georg Wolschin (U Heidelberg)
      • 44
        Pion Photoproduction on the Nucleons with the Unitary Isobar Model PionMAID

        The unitarity isobar model PionMAID is part of the Mainz MAID project with online
        programs performing real-time calculations of observables, amplitudes
        and partial waves (multipoles).
        The model has been developed to analyze new high
        precision data from A2 at MAMI, CBELSA/TAPS, GRAAL, and CLAS Collaborations
        for pion photoproduction on protons and neutrons.
        The background is described in a recently developed Regge cut model and
        Born terms. Resonance part includes 21 nucleon and 11 delta resonances
        parameterized with Breit-Wigner shapes.
        A new approach is discussed to avoid double
        counting in the overlap region of Regge and Resonances.
        The model describes data from the pion threshold upto W = 6 GeV.

        Speaker: Victor Kashevarov (Institut für Kernphysik, Mainz)
      • 45
        Exploring the strong interaction in three-body systems at the LHC

        In the journey to explore the strong interaction among hadrons, ALICE has for the first time flared out its femtoscopic studies to nuclei. The large data sample of high-multiplicity pp collisions
        √s = 13 TeV allows the measurement of the proton-deuteron (p-d) momentum correlations.
        The femtoscopic study of such systems opens the door to investigate the interaction in three-body systems as well as formation mechanism of the light nuclei in hadron-hadron collisions.
        In this contribution, the measured momentum correlation function for p-d is presented. The measured p-d correlation shows a shallow depletion at low relative momenta while the model calculation which assume the interaction of two point-like particles shows a clear discrepancy with respect to the data. This discrepancy can be resolved by employing a full three body wave function that accounts for the internal structure of the deuteron including all relevant partial waves and quantum statistical effects. This demonstrates that the study of correlations among light nuclei provides access to the details of the many-body system’s wave function at the LHC.

        Speaker: Bhawani Singh (Technical University of Munich)
      • 46
        Fron neutron stars to medical Imaging

        The hyperon puzzle, the observation that the two-solar-mass neutron stars existence is hardly explained by all models predicting the appearance of hyperons in the neutron star core is currently one of the unsolved key issues in the physics of compact stars. An experimental study of the reaction (e, e’K) on 208Pb 40 has been proposed by the Jefferson lab hypernuclear collaboration, and approved by the Jefferson Lab (JLab) PAC. The study of 208Pb with the (e,e'K+) reaction will provide a better binding energy resolution than that of the experiments performed so far with hadronic probes and thus a more detailed understanding of baryon behavior deep inside of the nucleus, providing important information for studying the Λ single-particle nature under high nucleon density. 208Pb is the ideal target to study hyperons in a medium closely resembling neutron star matter. This environment is best suited to the investigate the effects of three body forces involving hyperons which increase the stiffness of the nuclear matter equation of state, thus allowing for the existence of massive neutron stars compatible with the observational constraints. This experiment as well as the impact of the nuclear/hadronic physics on Medical Imaging techniques, so to human healthcare, both from technical and conceptual point of view will be described. Examples on advanced devices for the diagnosis of breast and prostate cancer will be outlined.

        Speaker: Dr Franco Garibaldi (INFN (Roma))
      • 47
        Concluding remarks

        Concluding remarks