EPPSU and the synergy of Astroparticle and Particle Physics
The European Particle Physics Update (EPPSU) process is conducted by CERN and it gives the guidelines for the future years to the particle physics community on scientific and technological programs, organizational aspects, knowledge and technology transfer as well as interaction with society, education and outreach1. The astroparticle physics community, and hence, APPEC, enters in this process since the strategy concerns also relations with external bodies and other fields of physics, which is covered by WG3 of the European Strategy Group (ESG). The APPEC Chair is participating to the ESG meetings and working groups of the ESG as an Observer. The ESG establishes periodically (last update was in 2013) a proposal in written form with a set of recommendations for CERN Council approval. The final document of this process will be written in the third week of January 2020 and approved in May 20, 2020 by the CERN council.
The Physics Preparatory Group (PPG) drafts its update proposal (the Briefing Book) taking into account the written inputs submitted by the community. S. Bentevelsen and M. Zito coordinate activities around the big questions on Neutrino and Cosmic Messenger, and M. Carena and S. Asai on the Dark Sector. In Dec. 2018, 160 inputs where provided by the community2 including inputs on the strategies of many organisations and laboratories. An Open Symposium was held in Granada in May 2019 to discuss these inputs. It is clear that Astroparticle is a domain of increasing interest, as shown in the table that was presented by S. Betke. APPEC presented its inputs and priorities which are described in this document and in the Open Symposium presentation by the Chair. The community submitted many documents, most of which fall in the priority areas of APPEC. These are: i) the dark matter searches; ii) the multi-messenger astronomy, in particular the third generation (3G) of gravitational wave (GW) experiment (ET); iii) the determination of neutrino nature and mass; iv) the European Astroparticle Theory Centre (EuCAPT).
Concerning dark matter searches it is advocated by APPEC and by the community itself that areas of synergy include exchange about common data interpretation and theory models. It would be beneficial to expand some platforms of discussion such as the Physics Beyond Colliders / LHC DM WG to include astroparticle physicists working on direct and indirect detection of dark matter. The synergy on technology developments, often in common with the CERN platform on cryogenics technology and photosensors is extremely important.The general hope is that cooperation between Astroparticle and Particle Physics communities will evolve towards a global program on dark matter searches, similar in breadth to the neutrino physics program (see below).
Concerning multi-messenger astrophysics, APPEC considers of highest priority the cooperation with CERN on establishing synergies with the multi-messenger astrophysics which has a high scientific potential. The future generation of gravitational wave detectors, the Einstein Telescope, has the capability to incorporate gravity within the model of fundamental interactions, to pin down the nature of dark matter, contribute to cosmology and to explore matter in extreme conditions. While the scientific cooperation is fundamentally important, areas of possible synergy are also on enabling technologies (such as vacuum and cryogenics technology, control and automation, electronics and DAQ, computing) as well as operation of underground facilities, governance models or open access data models.
The CERN platform is the extremely relevant outcome of the last EPPSU2013. This has made possible the preparation towards the large neutrino accelerator facilities such as DUNE and HK, which will shed light on remaining questions on the neutrino ordering and CP violation in the neutrino sector. The astroparticle community considers extremely important the cooperation of accelerator and atmospheric neutrino experiments to increase the precision in the parameters of the neutrino mixing matrix and the ordering. These measurements surely need as well cooperation with reactor neutrinos and in particular with JUNO. An area of important synergy with CERN concerns the hadroproduction experiments, which are relevant for neutrino and cosmic ray physics. The precision on the neutrino cross sections and on the calculations of the production of particles in atmospheric showers, are extremely important for the neutrino accelerator program and multi-messenger astrophysics. The astroparticle physics community and APPEC consider extremely relevant the experiments which will determine the nature of the neutrinos, Majorana or Dirac, and which may have access to the inverted ordering effective neutrino mass with the coming generation of detectors.
EuCAPT is becoming a reality in these days, with final agreements being signed by APPEC and CERN, the first host of EuCAPT for the first round of 5 years. A Steering board has been nominated with prominent scientists from many countries in cosmology, neutrino physics and multi-messenger astrophysics3 and they will nominate a Director for the General Assembly of APPEC to approve. EuCAPT will have a fundamental role for the common interpretation of data of accelerators and astroparticle experiments and for the definition of test models.
In conclusion, one sees currently a sort of unification of many present fields of fundamental science (particle and astroparticle physics, nuclear physics, astrophysics and cosmology). This unification concerns as much cross-correlations at the theoretical level, from where one sees the importance of EUCAPT as well as the R&D on common detectors, civil infrastructures and computing technologies for the dark matter, multi-messenger and neutrino physics. The unification extends to common methods concerning the data analytics and new deep/machine learning methods. Last but not least, the above situation creates an obvious obligation to diffuse and explain the current intense discovery environment to the society in general as well as the need to increase the innovation potential and the technological contributions addressing pressing environmental and societal issues. This situation reinforces our belief that we are facing a very exciting and productive decade.
by T. Montaruli (Chair of APPEC GA) Teresa.Montaruli@unige.ch
3 APC Paris: David Langlois, CERN Theory Department: Gian Giudice, DESY: Andrew Taylor, GRAPPA/Nikhef Amsterdam: Gianfranco Bertone, ICC Barcelona: Licia Verde, IFPU (SISSA+ICTP+INFN+INAF) Trieste: Piero Ullio, IPPP, Durham: Silvia Pascoli, IST Lisbon: Vitor Cardoso, OKC Stockholm: Hiranya Peiris] Paris-Saclay: Philippe Brax, Université de Genève: Antonio Riotto, University of Oxford: Subir Sarkar