XSCRC2024: Cross sections for Cosmic Rays @ CERN

16 Oct 2024, 09:00 → 18 Oct 2024, 14:00 Europe/Zurich

4/3-006 - TH Conference Room (CERN)

Fiorenza Donato (Torino University)

Cosmic-ray (CR) physics in the GeV-TeV range has entered a precision era with recent data from space-based experiments. However, the poor knowledge of nuclear reactions (production of antimatter and secondary nuclei) limits the information that can be extracted from these data (such as source properties, transport in the Galaxy, indirect searches for dark matter).

The first edition of this workshop was held in 2017 (XSCRC17). Its goal,  bringing together different communities (CR theorists, CR experimentalists, nuclear and particle physicists), was to review theoretical motivations for CR studies, new CR data, and how the modelling of CRs crucially depends on nuclear reactions. The workshop was also strongly aimed at presenting current efforts and discussing forthcoming perspectives for particle/nuclear measurement campaigns.

This second edition , XSCRC2019, reviewed the advances made and highlighted some results obtained thanks to collaborations started during the first edition.

The 2024 edition will further strengthen these emergent synergies, taking advantage of the complementarity and know-how in different communities: the challenges that pose the interpretation of high-precision CR data can only be undertaken with a collective and coordinated effort.

Duration: The workshop will start Wednesday, October 16th at 2pm, and will end Friday, October 18th by 1pm.  

Organizing Committee:  Fiorenza Donato (chair), Saverio Mariani (co-chair), David Maurin (co-chair)

Scientific Advisory Committee: Denise Boncioli (L'Aquila Univ.), Michela Chiosso (Torino Univ.), Gian Giudice (CERN), Giacomo Graziani (INFN Florence), Mercedes Paniccia (Geneva Univ.), Pasquale D. Serpico (LAPTh, CNRS), Vincent Tatischeff (IJClab, CNRS), Philip von Doetinchem (Hawaii Univ.)

Invited Speakers:  Laurent Audoin (Université Paris-Saclay, CNRS/IN2P3, IJC Lab), Eugenio Berti (INFN Firenze), Mattia Di Mauro (Torino INFN), Carmelo Evoli (Gran Sasso Science Institute), Davide Giordano (Torino INFN and Univ.), Maximilian Horst (Technische Universitaet Muenchen (DE)), Chiara Lucarelli (INFN Firenze), Paolo Maestro (Pisa INFN, Siena Univ.), David Maurin (LPSC Grenoble), Alberto Oliva (INFN Bologna), Luca Orusa (Princeton Univ.), Mercedes Paniccia (Geneva Univ.), Tanguy Pierog (KIT, Karlsruhe, IKP), Laura Serksnyte (TUM Munich), Andrii Tykhonov (Geneva Univ.), Michael Unger (KIT, Karlsruhe, IAP), Marie Vanstalle (Strasbourg University)

 

Wednesday 16 October

Welcome

1 Welcome to CERN

2 Organisation of the workshop

Speaker: Prof. Fiorenza Donato (Torino University)

Introduction and motivation: astrophysics and dark matter

3 Galactic Cosmic Ray transport and XS [20'+10']

Speaker: Dr Carmelo Evoli (Gran Sasso Science Institute)

4 Relevance of cross sections for indirect dark matter detection [20'+10']

The origin of dark matter remains one of the most puzzling open problems in physics. Understanding its particle nature is a central focus of theoretical research and a primary objective for several experimental efforts. Among the various strategies for dark matter detection, indirect detection stands out as one of the most promising. This approach seeks to identify signals in flux data of the rarest cosmic particles (such as neutrinos, photons, or antimatter) originating from dark matter beyond the known astrophysical sources and mechanisms.

In this talk, I will review the current status of dark matter indirect detection, with a particular emphasis on the crucial role of cross-section measurements relevant for astroparticle physics. I will demonstrate how achieving the discovery potential for dark matter is contingent upon obtaining precise measurements of these cross sections.

Speaker: Mattia Di Mauro (INFN Torino)

Galactic Cosmic Ray data

5 Selected results from AMS-02 [15'+10']

Speaker: Dr Mercedes Paniccia (Universite de Geneve (CH))

6 Nine years of charged cosmic ray measurements with CALET on the International Space Station [15'+10']

The CALorimetric Electron Telescope (CALET) is a high-energy cosmic-ray detector that has been in continuous operation on the International Space Station (ISS) since October 2015. Developed by JAXA in collaboration with ASI and NASA to study the origin of cosmic rays (CR), their acceleration and propagation mechanisms in the Galaxy, and to search for dark matter and the presence of potential nearby astrophysical sources of high-energy electrons, CALET has so far detected more than 2 billion events with an energy >10 GeV. The analysis of these data allowed to measure the energy spectra of electron+positron and individual CR nuclear species up to the multi-TeV region, revealing spectral features such as a sharp break in the electron flux around 1 TeV, the hardening of the proton, He, C, O fluxes at a few hundred GeV/n and the softening of the proton and He spectra around 10 TeV/n.
In addition, the measurement of the B/C and B/O flux ratios up to a few TeV/n indicates the possible presence of a residual propagation length compatible with the hypothesis that a fraction of secondary B nuclei can be produced in the vicinity of the cosmic ray source.
I will summarise these results obtained with CALET, highlight similarities and discrepancies with measurements from other recent experiments, and discuss the main sources of systematic uncertainties affecting the spectra.

Speaker: Paolo Maestro (Universita degli studi di Siena (IT))

16:05 Coffee break - TH common room

XS from space and XS for Ultra-high energy CRs

7 Measuring the inelastic cross section of proton and helium-4 in space with DAMPE [10'+5']

The Dark Matter Particle Explorer (DAMPE) is an ongoing space-borne experiment for the direct detection of cosmic rays (CR). Thanks to its large geometric acceptance and thick calorimeter, DAMPE is able to detect CR ions up to unprecedented energies of hundreds of TeV. Following by now more than 8 years of successful operation, DAMPE has amassed a large dataset of high-energy hadronic interactions in a regime that is often difficult to probe by accelerator experiments. In this contribution, we show how DAMPE data can be used to measure inelastic ion-nucleon cross sections, and present a cross section measurement of both proton and helium-4 on the BGO calorimeter. Our measurements are compared to previous results from accelerator experiments and current cross section models such as EPOS-LHC, QGSJETII-04, and DMPJET3.

Speaker: Paul Coppin (Universite de Geneve (CH))

8 Ultra-heavy nuclei and ultra-high-energy cosmic rays [10'+5']

Thanks to the experimental advancements in the field of ultra-high-energy cosmic rays (UHECRs), recent results about their mass composition indicate that, as the energy increases, the mean mass of these nuclei first decreases, reaching its lightest point around 2 EeV, and then afterward, increases significantly.

These results motivated several studies for modelling the interactions suffered by UHECR particles in their travel from the sources to the edge of the Milky Way, to compute the nuclear cascades induced by their interactions with the background photons in the extragalactic space.

Nuclear species with atomic mass A<=56 are treated in the most common codes used in the UHECR community to simulate the extragalactic propagation. In this talk, I will motivate why heavier nuclei should be considered as well, in the light of the highest energy events detected at the UHECR observatories. In addition, I will discuss how to possibly include the corresponding cross sections in SimProp, a simulation code for the simulation of UHECR interactions in the cosmic microwave background and extragalactic background light.

Speaker: Prof. Denise Boncioli (University of L'Aquila)

9 Measurement of the proton-proton cross section at ultra-high energies with the Pierre Auger Observatory [10'+5']

The energies of cosmic rays significantly exceed the range of the existing human-made particle accelerators. The analysis of the air shower data makes it possible to infer the particle production cross sections - one of the most fundamental properties of soft QCD interactions at the highest energies. The depth at which the number of particles in a shower reaches its maximum is linked to the depth of the first interaction in the atmosphere, which is determined by the cross section of the particle initiating the shower in the air. In this contribution, we discuss the estimation of the proton-proton cross section from the depth of shower maxima observed with the Pierre Auger Observatory. The results are compared with standard extrapolations from low-energy accelerator data and are in good agreement. The systematic uncertainties of the analysis and the integrity of the underlying assumptions are evaluated and summarized. The interplay of the production cross section with mass composition and the possibility of the corresponding simultaneous measurement of both quantities is outlined.

Speaker: Dr Olena Tkachenko (Institute of Physics of the Czech Academy of Sciences)

10 Photonuclear cross sections and UHECR transport: towards more transparency [10'+5']

Studies of the origin and composition of ultra-high-energy cosmic rays involve simulating their interactions, predominantly with surrounding photon fields and involving photonuclear cross sections in the MeV-GeV range. Although such interactions within the source and during extra-galactic propagation are analogous, these scenarios are addressed separately and the codes employed for each of them are different. Evaluating the impact of cross sections in this way can be quite complex and the cross section datasets used for each scenario are often inconsistent. This contribution presents an approach that allows a consistent treatment of in-source and extra-galactic propagation, and is better suited to explore the impact of cross section uncertainties. The approach is based on analytic functions describing the probabilistic behavior of Continuous Time Markov Chains, which are well suited for nuclear cascades produced in UHECR interactions even when the target photon fields are variable in time. Examples illustrating the connection between the photonuclear cross sections and the evolution of UHECR composition are discussed.

Speaker: Leonel Morejon (Wuppertal University)

Thursday 17 October

XS measurements at CERN

11 AMBER [15'+10']

Speaker: Davide Giordano (INFN Torino)

12 ALICE [15'+10']

Speaker: Laura Šerkšnytė (Technische Universitaet Muenchen (DE))

13 Antihelium production at LHC and in Space [10'+5']

The production of prompt antihelium in pp and pA collisions, as well as displaced
antihelium from hypertriton and Lb decays have been recently studied with the LHCb detector.
Recent results are presented and the implication to Cosmic Rays are discussed.

Speaker: Valery Zhukov (Rheinisch Westfaelische Tech. Hoch. (DE))

Relevant XS reactions and precision for GCRs

14 Desired reaction for nuclear production XS [15'+10']

Speaker: David Alain Maurin (Centre National de la Recherche Scientifique (FR))

15 Production cross sections of electron, positrons and gamma rays [15'+10']

Accurate interpretation of cosmic-ray electron and positron fluxes, as well as gamma-ray emissions, requires precise knowledge of the cross sections governing cosmic-ray interactions with the interstellar medium. Primarily involving protons and helium, these reactions produce secondary positrons and gamma rays, key observables for probing cosmic-ray propagation, dark matter searches, and the study of astrophysical sources such as pulsars and supernova remnants.

In this talk, I will present updated models for the hadronic production cross sections of positrons, electrons, and gamma rays, focusing on pion and kaon production directly obtained from collider data. I will also discuss the challenges posed by cross section uncertainties, identifying which measurements are needed to improve our modeling, and how these cross sections influence the accuracy of theoretical models in comparison with data from space-borne observatories like AMS-02 and ground-based gamma-ray telescopes such as Fermi-LAT.

Speaker: Luca Orusa (University of Torino)

11:00 Coffee break - Mezzanine

in front of the main Auditorium

XS measurements at other facilities

16 XS nuclear fragmentation at GANIL and GSI [15'+10']

Speaker: Mr Laurent Audoin (IJCLab)

17 XS for hadrontherapy and space studies with the FOOT project [15'+10']

Speaker: Marie Vanstalle (GSI)

XS modelling

18 EPOS [15'+10']

Speaker: Dr Tanguy Pierog

19 Antinuclei coalescence [15'+10']

Speaker: Maximilian Mahlein (Technische Universitaet Muenchen (DE))

20 Antinucleon-nucleus interactions with the INCL code [10'+5']

Speaker: Jean-Christophe David

13:25 Lunch Break

XS measurements at CERN

21 LHCf [15'+10']

Speaker: Eugenio Berti (Universita e INFN, Firenze (IT))

22 LHCb [15'+10']

Speaker: Chiara Lucarelli (Universita e INFN, Firenze (IT))

23 NA61 and nuclear production XS [15'+10']

Speaker: Michael Unger (Karlsruhe Institute for Technology)

15:45 Coffee break - TH common room

Brainstorming on a roadmap: preparing a white paper (TBC)

24 Roadmap for production XS for nuclei (panel discussion)

25 Roadmap for anti-nuclei XS (panel discussion)

26 Roadmap for other XS and models (panel discussion)

Friday 18 October

Galactic Cosmic Ray data

27 Selected DAMPE results [15'+10']

Speaker: Andrii Tykhonov (Universite de Geneve (CH))

28 Future precision experiments in CRs [15'+10']

Speaker: Alberto Oliva (Universita e INFN, Bologna (IT))

Relevant XS reactions and precision for GCRs

29 Deuteron and Helium-3 production cross sections and propagation in the Galaxy [10'+5']

The AMS collaboration has published recent results on deuteron-over-helium-4 ($d$/$^4$He) and helium-3-over-helium-4 ($^3$He/$^4$He) cosmic rays flux ratios with unprecedented precision and covering a wider energy range than previous experiments. Both $d$/$^4$He and $^3$He/$^4$He ratios are important to understand the propagation of cosmic rays in the Galaxy and the heliosphere, complementing observations with heavier nuclei like the boron-to-carbon ratio. Interestingly, the AMS has found that deuterons have a sizeable primary-like component, instead of being mostly secondary as expected. To better interpret such revealing observations is necessary to understand in more detail the secondary component that depends on production cross sections, propagation parameters in the transport model, and their uncertainties.
In this work, we revisit the deuterons and helium-3 production cross sections through fragmentation of heavier nuclei, as well as their uncertainties, and we study their propagation in the Galaxy comparing the resulting flux ratios to AMS measurements.

Speaker: Diego Mauricio Gomez Coral (Universidad Nacional Autonoma (MX))

30 Measurement of proton spallation cross-sections of natCr and 55Mn between 0.2-2.5 GeV relevant to galactic cosmic ray propagation [10'+5']

TIGERISS, the recently selected Pioneers mission, will look at elemental abundances across a wide Z range, from 5B up to 82Pb, for the first time with a single instrument, to further our knowledge of the way the galaxy redistributes elements. However, accurate cross section data is paramount to the accurate interpretation of this observed experimental data. High Z (>Z) proton spallation reaction channels and the sub-Fe region isotopes (which are crucial for constraining re-acceleration models) are lacking in cross-section data, especially at higher energies. To address this shortage, our team at NASA Goddard has established a collaboration with various institutes worldwide (Brookhaven National Laboratory, Facility for Rare Isotope Beams, NA61 at CERN) to perform a series of cross-section experiments for the reaction channels of utmost importance to the study of galactic cosmic ray propagation. The first of these experiments was performed in March 2024, at Brookhaven National Lab. Proton beams with energies between 0.2 to 2.5 GeV were irradiated upon a natural Cr and a monoisotopic Mn target, and the cross sections of several nat Cr(p,X) and Mn (p,X) reactions are currently being determined, using known gamma-ray lines of unstable daughter products. We will report upon the results of this experiment, and our future plans in this endeavour.

Speaker: Priyarshini Ghosh (NASA Goddard Space Flight Center)

31 The Fluka cross sections for secondary cosmic rays: Latest results [10'+5']

Despite the simplicity of our phenomenological models of CR propagation, we have been able to explain with very good accuracy the fluxes of the main secondary CRs, including antiprotons. In this talk, we show new cross sections of CR interactions in the Galaxy computed with FLUKA, covering from light secondaries, such as deuterium, tritium or 3He, to gamma rays and neutrinos. In addition, we show how some assumptions, such as the head-on approximation, can affect our predicted fluxes of light secondary CRs.

Speaker: Pedro De la Torre Luque (Institute of theoretical physics (IFT-UAM))

32 Data-driven constraints on cosmic-ray diffusion: Probing self-generated turbulence in the Milky Way [10'+5']

The AMS-02 experiment has provided high-precision measurements of several cosmic-ray (CR) species. We exploit the AMS-02 data to investigate CR propagation in the Galaxy, and provide updated constraints on reacceleration, convection, and the spatial and rigidity dependence of the diffusion coefficient. We explicitly consider the impact of the uncertainties in the nuclear production cross-sections of secondaries. Our findings favor models with a smooth behavior in the diffusion coefficient, indicating a good qualitative agreement with the predictions of self-generated magnetic turbulence models. Instead, the current cosmic-ray data do not exhibit a clear preference for or against inhomogeneous diffusion, which is also a prediction of these models.

Speaker: Alessandro Cuoco

33 From the AMS-02 isotope fluxes to their production cross sections [10'+5']

The AMS-02 collaboration has reported preliminary results on beryllium and lithium isotope fluxes, extending the energy range beyond that of previous experiments. As secondary CRs, the Be isotopes include both stable and unstable species, which are crucial for constraining the propagation parameters of the Galactic CRs. The $\rm^{10}Be/^9Be$ ratio measured by AMS-02 can better resolve the degeneracy between the CR diffusion coefficient and the diffusion halo height. However, the inadequate production cross-section measurements introduce significant uncertainties in the propagation parameters.

In this study, we innovatively use $\rm^7Be$ instead of $\rm^9Be$ to provide better constraints on the propagation parameters, benefiting from the much more precise cross-section measurements of $\rm^7Be$. More intriguingly, using the derived propagation parameters, we inversely constrain the production cross sections of $\rm^9Be$ by interpreting its CR energy spectrum. Our findings suggest remarkably lower cross sections of $\rm^9Be$ than previously estimated. This method demonstrates the potential of using precise isotope measurements from space-based CR experiments to calibrate the production cross sections of nuclei. Our next step is to apply this method to examine the production cross sections of lithium isotopes.

Speaker: Meng-Jie Zhao (Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences)

11:05 Coffee break - TH common room

Brainstorming on a roadmap: preparing a white paper (TBC)

34 2-slide summary of the 3 panel discussion [3x10']

35 Organisation to write white paper - TBC [20']

Speakers: David Alain Maurin (Centre National de la Recherche Scientifique (FR)), Prof. Fiorenza Donato (Torino University), Saverio Mariani (CERN)

36 Concluding remarks [5']

Speaker: Prof. Fiorenza Donato (Torino University)