GGI workshop Colliders Physics and the Cosmos 25

GGI workshop: ”Colliders Physics and the Cosmos” (25 th -29 th September 2017) Collider Physics, High Energy Cosmic Rays and Neutrinos (25 th -29 th September 2017) A summary of the main points Frank Deppisch, Ralph Engel, Paolo Lipari, James Pinfold

The Talks 1. Neutrinos, 0 nbb and the LHC – Frank Deppisch 2. Searching for Monopoles and Other Exotica at Colliders and in Cosmic Rays – James Pinfold 3. From the Knee to the Ankle – What Astroparticle physics and Collider physics together can say about the main features of the cosmic ray energy spectrum – Paolo Lipari 4. Ultra-High-Energy Cosmic Rays and Hadronic Interactions Part 1: Cosmic-Ray Physics – Ralph Engel 5. Ultra-High-Energy Cosmic Rays and Hadronic Interactions Part 2: Particle Physics Aspects – Ralph Engel

Neutrinos, 0 nbb and the LHC • Neutrinos much lighter than other fermions – Dirac or Majorana? Lepton Number Violation? – ◦Neutrino masses need BSM physics, but at what scale? • Neutrino physics is BSM physics – Neutrino mass models can be searched for at LHC – Wide range of scenarios and signatures • Observation of LNV processes – Likely pinpoints the origin of neutrino mass generation – Can falsify high scale baryogenesis scenarios • Important information for model selection, e. g. – Observation of 0 nbb – Observation of LNV at the LHC

Searching for Monopoles and Other Exotica at Colliders and in Cosmic Rays • Mo. EDAL is the newest experiment at the LHC that started data taking at √s=13 Tev in 2015 – Aim to search for highly ionizing avatars of new physics, very longlived particles and highly penetrating phenomena – Complementary to general purpose LHC detectors ATLAS & CMS – The search for the magnetic monopole uo to 6 -7 Te. V mass is a key aim, but many others defined (Int. J. Mod. Phys. A 29 (2014) 1430050) – Possible use of MAPP (Mo. EDAL Apparatus for Long-Lived particles) subdetector propoed at this meeting, for • Searching for heavy sterile neutrinos (RE: Frank’s talk) • High energy muons studies useful in understanding cosmic muons may be possible – the possibility arose from the meeting (RE: Ralph’s 2 nd talk on the muon problem)

Mo. EDAL Apparatus for Penetrating Particles (MAPP) MAPP will be able to take data in p-p, p-A, A-A and also fixed target interactions using SMOG (an internal gas target in LHCb) MAPP has three motivations To search for particles with charges <<1 e (ATLAS & CMS limited to searches with particles of charge e ≥ 1/3) To search for new pseudo-stable neutrals with long lifetime and anomalously penetrating particles 10

Cosmic-Mo. EDAL • With a high altitude, large area array using same Nuclear Track Detector Technology used in Mo. EDAL we can extend the search for monopoles from the LHC’s Te. V scale to the GUT scale. • Such a array can also search for other exotic cosmic particles: Q-balls, nuclearites, primordial black holes, microscopic black hole remnants and other highly ionizing particles produced in UHECR air showers • A good example of the synergy between collider and cosmic ray physics that is the topic of this meeting • The initial planning is now underway

From the Knee to the Ankle…. . • Overview of the landscape of cosmic ray air shower physics and its synergy with particle physics • Uncertainties in the air shower models – Need to include diffraction, elastic scattering, etc. • “An understanding of the origin of the positron and antiproton fluxes is of central importance for High Energy Astrophysics” • The e-, e+, p-bar spectra found from AMS, PAMELA, etc. – What can we learn from the ration of e+/p-bar – why are they similar (e+/p -bar ~ 2 at E > 30 Ge. V)? – Is there a secondary origin for both fluxes – Is he energy dependence of the e-/p fluxes NOT the effect of propagation, but formed at injection? – Is there a new source of positrons to compensate for energy loss of positrons? – Will the spectrum turn down? Etc.

Ultra-High-Energy Cosmic Rays and Hadronic Interactions Part 1: Cosmic-Ray Physics • AUGER and TA description and differences • What is the origin of the flux suppression at 6 x 1019 e. V? • Composition estimate using rise time of signal and shower fluctuations • Composition dependence changing with energy • Change of model predictions thanks to LHC data • Proton-air cross-sections • Large Scale anisotropy • Transition from galactic to extragalactic CRs • Photon and neutrino fluxes at very high energies • TA x 4 Project and Auger. Prime status and physics reach

Ultra-High-Energy Cosmic Rays and Hadronic Interactions Part 2: (1) • Composition interpretation essential for understanding astrophys • LHC data of central importance for more reliable composition interpretation – Good collaboration between members of CR community & LHC/HEP – Feedback from air-shower observations, CR int. models successful at LHC • Cosmic ray data at 1019. 5 e. V likely not protons (except exotic physics) • p interactions as major uncertainty for muon discrepancy id’ed – Need measurement of energy dependence of ρ0 production – Consistent description at lower energy, transition to direct measurements • Forward charm production of increasing interest • Primary flux composition also directly linked to inclusive lepton fluxes

Ultra-High-Energy Cosmic Rays and Hadronic Interactions Part 2: (2) • So far models only tuned for p-p interactions (& partially p-Pb, Pb -Pb) – – – Models with similar p-p predictions differ significantly for p-O EG: difference in multiplicity prediction of models corresponds to difference between p and He of cosmic ray particles (ΔXma ~20 g/cm 2) Forward particle production in p-O essentially unknown Peripheral collisions in p-O much more important than in p-Pb Model predictions give only lower limit to real uncertainty due to similar assumptions, – need data to estimate real uncertainty