International Symposium on Future Directions in UHECR Physics

13 Feb 2012, 14:00 → 16 Feb 2012, 18:00 Europe/Zurich

500/1-001 - Main Auditorium (CERN)

This Workshop is the follow-up of the Nagoya Symposium 2010

Scope of the Workhop:

• Discuss the highlights and challenges of UHECR observations
• Prepare for a next-generation ground based giant detector
• Evaluate the complementarity of ground and space based observations
• Identify technological challenges and related R&D works

Circular

• FinalCircular.pdf
• FinalCircular.pdf
• Tram_to_CERN.png

Photo UHECR-Photo.jpg UHECR-Photo-vsmall.jpg

Poster UHECR2012.pdf

Proceedings style epjconf_1col.docx epjconf_1col.pdf

Programme layout

• UHECR_sessions.pdf
• UHECR_sessions.pdf
• UHECR_sessions.pdf

Monday, 13 February

Introduction

Convener: Dr James W Cronin (University of Chicago)

1 Welcome address

Speaker: Sergio Bertolucci (CERN)

2 History of UHECR research

Speaker: pierre sokolsky (university of Utah)

Slides 01_Sokolsky.pdf

3 Review of current status of measurements

Speaker: Paolo Privitera (Dipartimento di Fisica(RomaII))

Slides 02_Privitera.pdf

15:45 Coffee Break

Theoretical challenges of UHECR

Convener: Gustavo Medina Tanco (Instituto de Ciencias Nucleares - UNAM)

4 Acceleration and propagation

Speaker: Prof. Pasquale Blasi

Slides 03_Blasi.pdf

5 Review of model predictions on spectrum/composition

Speaker: Venya Berezinsky (INFN Laboratori Nazionali del Gran Sasso)

Slides 08_Berezinsky.pdf

6 Connecting accelerator experiments and cosmic ray showers

Speaker: Dr Tanguy Pierog (KIT)

Slides 05_Pierog.pdf

18:15 Welcome reception in the Globe

Tuesday, 14 February

09:00 Conference Photo

Conference Photo in front of Bat. 500 at 9:00 AM

Experimental challenges of UHECR

Convener: Prof. Bruce Dawson (University of Adelaide)

7 HiRes and TA Spectrum Measurements

HiRes was the first experiment to observe the GZK Cutoff. This was accomplished using the fluorescence technique with monocular reconstruction with a heavy reliance on Data/MC comparison techniques borrowed from particle physics. This result was later confirmed using stereo reconstruction and by the Pierre Auger Observatory. The HiRes result is consistent with the original motivation for the GZK Cutoff, protons interacting with the Cosmic Microwave Background Radiation to produce the delta resonance. Telescope Array has now also measured the ultra-high energy spectrum, showing remarkable agreement in detail with the HiRes measurements despite using significantly different observational methods, namely a hybrid measurement involving both surface detectors and fluorescence detectors. Both the use of a fluorescence energy scale and the reliance on Data/MC comparison techniques in determining the aperture link the TA and HiRes results.

Speaker: Douglas Bergman (U)

Slides 73_Bergman.pdf

8 Measurement of the energy spectrum of cosmic rays at highest energies using the Pierre Auger Observatory

We report a measurement of the flux of cosmic rays with unprecedented precision and statistics using the Pierre Auger Observatory. Based on fluorescence observations in coincidence with at least one surface detector we derive a spectrum for energies above 10^18 eV. We also report on the energy spectrum obtained with surface detector arrays of 1500m and 750m spacing for events with zenith angles less than 60 degrees and 55 degrees respectively. The spectrum derived from inclined events will be given account as well. The spectral features are presented in detail and the impact of systematic uncertainties on these features are addressed.

Speaker: Ioana Maris

Slides 102_Maris.pdf

9 The Yakutsk array experiment: main results and future directions

The results of the Yakutsk array experiment aimed at investigations of ultra-high energy cosmic rays are presented. We outline the current status of the instrument and an outlook for future directions and areas of study.

Speaker: Anatoly Ivanov (Shafer Institute for Cosmophysical Research & Aeronomy)

Slides 98_Ivanov.pdf

10 WG Review of UHECR spectrum data

Speaker: Yoshiki Tsunesada (Tokyo Institute of Technology)

Slides 06_Tsunesada.pdf

11 Nitrogen fluorescence in air for observing extensive air showers

Extensive air showers initiate the fluorescence emissions from nitrogen molecules in air. The UV-light is emitted isotropically and can be used for observing the longitudinal development of extensive air showers in the atmosphere over many kilometers. This measurement technique is well established since it has been used since many decades by several cosmic ray experiments. However, a fundamental aspect of the air shower analyses is the description of the fluorescence emission in dependence on varying atmospheric conditions. Different fluorescence yields affect directly the energy scaling of air shower reconstruction. In order to explore the various details of the nitrogen fluorescence emission in air, few experimental groups were performing dedicated measurements over the last decade. Most of the measurements are now finished. These experimental groups have been discussing their techniques and results in a series of Air Fluorescence Workshops commenced in 2002. At the 8th Air Fluorescence Workshop 2011, it was suggested to develop a common way of describing the nitrogen fluorescence for application to air shower observations. Here, first analyses for a common treatment of the major dependences of the emission procedure are presented. Aspects like the contributions at different wavelengths, the dependence on pressure, the temperature dependence of the collisional cross sections between molecules involved, and the collisional de-excitation by water vapor are discussed.

Speaker: Dr Bianca Keilhauer (KIT)

Slides 35_Keilhauer.pdf

11:10 Coffee break

UHECR and particle shower

Convener: Prof. Gordon Thomson (University of Utah)

12 Mass Sensitive Observables of the Pierre Auger Observatory and Their Possible Implications

In this presentation we will discuss measurements of the longitudinal development of air showers at the Pierre Auger Observatory. The longitudinal development can be directly observed by the fluorescence telescopes of Auger and we will present the results on the evolution of the average of the shower maximum and its fluctuations as a function of energy. Moreover, two observables from the surface detector, the asymmetry of the rise time and the muon production depth, will be discussed and the measurements will be compared to predictions from air shower simulations for different primary particle types.

Speaker: Michael Unger (KIT - Karlsruhe Institute of Technology (DE))

Slides 104_Unger.pdf

13 HiRes and TA Composition Measurements

In order to clarify the origin of ultra high energy cosmic rays (UHECRs), it is very important to determine the mass composition. The most effective strategy to determine the mass composition is Xmax technique. Xmax is the atmospheric depth of air shower maximum measured by fluorescence detectors (FDs). HiRes has reported Xmax measurement by FDs which indicated proton dominated mass composition. Now, Telescope Array (TA) experiment has also measured UHECRs with FDs. In this presentation, the detail of mass composition analysis and result of TA experiment will be reported and compared with HiRes experiment.

Speaker: Yuichiro Tameda (Institute for Cosmic Ray Research, University of Tokyo)

Slides 75_Tameda.pdf

14 WG Review of UHECR composition data

Speaker: Dr Jose Bellido (The University of Adelaide)

Slides 07_Bellido.pdf

13:00 Lunch break

Theory and measurement of UHECR flux and composition

Contributed talks 6 x 15+5 min

Convener: Prof. James Matthews (Louisiana State University)

15 Particle physics connection

Speaker: Jonathan R. Ellis (CERN)

Slides 04_Ellis.pdf

16 Review of accelerator data of relevance to shower simulation

Speaker: Prof. Yoshitaka Itow (Nagoya University)

Slides 09_Itow.pdf

17 Recent results from LHCf

The Large Hadron Collider forward experiment measured very forward neutral particle spectra in LHC proton-proton collisions in early 2010. In this talk we will discuss the energy and transverse momentum spectra of neutral pion at the 7TeV proton-proton collision, and also present the inclusive photon energy spectra taken at the 900GeV collisions. The spectra in both collision energy are also compared with the predictions of several hadronic interaction models that are often used for high energy particle physics and for modeling ultra high energy cosmic ray showers. Finally we will argue the capability of LHCf to measure a proton-lead collision events that is under discussion for the 2012.

Speaker: Gaku Mitsuka (Nagoya University (JP))

Slides 23_Mitsuka.pdf

18 Estimates of the proton-proton cross section at UHE energy

This contribution discusses possible methods to measure the proton-proton total cross section from observations of Ultra High Energy cosmic rays, and the theoretical uncertainties associated with these methods.

Speaker: Prof. Paolo Lipari (Universita di Roma I)

Slides 99_Lipari.pdf

16:00 Coffee break

Theory and measurement of UHECR flux and composition

Contributed talks 6 x 15+5 min

Convener: Prof. Peter Grieder (University of Bern)

19 Measurement of the proton-air cross section with the Pierre Auger Observatory

Authorship: The Pierre Auger Collaboration. Using the tail of the distribution of the depth of shower maxima observed with the Pierre Auger Observatory, we derive an estimate of the proton-air cross section for particle production at center-of-mass energies of 57 TeV. Air showers observed with the fluorescence detector and at least one station of the surface array are analyzed in the energy range from 10^18 to 10^18.5 eV. Systematic uncertainties of the cross section estimate arising from the limited knowledge of the primary mass composition, the need of using shower simulations, and the selection of showers are studied in detail.

Speaker: Dr Ralf Matthias Ulrich (KIT - Karlsruhe Institute of Technology (DE))

Slides 84_Ulrich.pdf

20 Measurements of the muon shower content at the Pierre Auger Observatory

Various methods of estimation of the muonic part of the signal observed in the surface Cherenkov detectors have been developed within the Pierre Auger Collaboration in the recent years. Muon shower content, derived from data with these methods, is larger in comparison with predictions of QGJSET II and EPOS 1.99 interaction models. The zenith angle dependence of the muon deficit in simulations with respect to data is discussed.

Speaker: Alexey Yushkov

Slides 88_Yushkov.pdf

21 New Physics at UHE energies

Ultrahigh energy cosmic rays (UHECRs) are the highest energy particles in the Universe, recorded to have energies up to 100 million times greater than the LHC beams. Whether they are protons or nuclei and how they are accelerated are presently unknown. The particle cascades created when these UHECRs interact in the atmosphere are not well-described by simulations, but since the primary composition is unknown and the particle physics models must be extrapolated far beyond accelerator energies, the origin and extent of the discrepancies have not been clear. By combining information from the longitudinal and lateral properties of the showers, measured in detail by the Pierre Auger Observatory, we are lead to the seemingly-inescapable conclusion that there is a fundamental change in the nature of the final states produced in ultrahigh energy interactions. It has distinctive features which suggest that a new phase of matter is being produced, and we conjecture it results from the restoration of chiral symmetry in a new high temperature regime of Quantum Chromodynamics, not accessible in accelerator experiments. In the conditions probed in particle physics experiments to date, chiral symmetry is broken and the lightest strongly interacting particle is the pion, a quark - anti-quark bound state. Chiral symmetry restoration has been predicted theoretically at temperatures above the Deconfinement Phase Transition, responsible for the Quark-Gluon Plasma created in relativistic heavy ion collisions, but its possible creation in 1 UHE collisions was not anticipated. Although pions and other mesons would not exist in a chiral symmetric phase, we present theoretical arguments that baryons and anti-baryons remain bound. As a result, baryons and anti-baryons could be produced much more abundantly relative to mesons, than at accelerator energies. This picture provides the first consistent description of the published Auger observations on both the magnitude and zenith angle dependence of the ground signal, and the longitudinal profiles. Auger measurements should be able to test our claim that new physics is needed to explain UHE air showers, explore how the meson-baryon balance evolves with energy, and possibly determine the composition of the UHECRs. With a substantially larger sample of UHE hybrid events, it should be possible to investigate in considerable detail the production and properties of this ultimate phase of matter.

Speaker: Prof. Glennys Farrar (New York University)

Slides 103_Farrar.pdf

22 New technique and results of cosmic ray investigations in the energy interval 10^15 – 10^19 eV

New technique of EAS investigations by means of the method of local muon density spectra (LMDS) is developed. Application of this method to investigations of inclined EAS allows exploration of CR energy interval from 10^15 to 10^19 eV by means of a relatively small detector with area ~100 m^2 due to very strong dependence of EAS muon density on zenith angle. During 2002-2007, long-term NEVOD-DECOR experiment (about 20 thousand hours) was conducted and more than two million muon bundles in zenith angle interval 30 – 88 degrees were registered. Comparison of experimental data with results of CORSIKA simulations showed that the new method is sensitive to all main peculiarities of CR energy spectrum: the knee, increase of the energy spectrum slope with energy, the second knee. But the observed progressive excess of muon bundles with increasing primary CR energy in comparison with simulations (even for pure iron composition) indicates the appearance of new processes of muon generation. This result, together with observations of numerous unusual events and phenomena in various CR experiments – halos, alignment, penetrating cascades, long-flying component, large transverse momenta, Centauros, excess of VHE (~ 100 TeV) single and multiple muons, etc. – can be explained in frame of a single model if to suppose the production of blobs of quark-gluon plasma with large orbital momentum in nuclei collisions. This hypothesis drastically changes all cosmic ray physics at energies above the knee and interpretation of the results of all experiments at these energies. The correctness of this hypothesis can be checked both in LHC experiments and in CR investigations. At that, CR experiments have some advantages in comparison with LHC experiments, since the main signature of new processes are muons which will have energies ~ 100 TeV in cosmic rays and about several tens GeV in LHC experiments. It is difficult to separate such muons from particles produced in usual processes. Preliminary results of CR muon energy spectrum measurements (BUST in Russia and IceCube in Antarctica) exhibit a noticeable excess of muons with energies > 100 TeV, which evidences in favor of the new model of hadron interaction. In this case, for correct investigations of EAS, the experimental arrays must be supplemented by detectors which can measure or evaluate the energy of muons.

Speaker: Prof. Anatoly Petrukhin (MEPhI)

Slides 29_Petrukhin.pdf

23 WG Review of modeling and description of air showers

Speaker: Dr Ralph Engel (Forschungszentrum Karlsruhe)

Slides 10_Engel.pdf

Poster session

Lobby in front of Auditorium

Wednesday, 15 February

UHECR - astrophysics and multi-messenger

Convener: Piera Luisa GHIA (LPNHE-CNRS)

24 WG Review of anisotropy data

Speaker: Prof. Peter Tinyakov (Universite Libre de Bruxelles)

Slides 11_Tinyakov.pdf

25 WG Review of UHE multi-messenger data

Speakers: Dr Grigory Rubtsov (Institute for Nuclear Research of RAS), Markus Risse (University of Siegen)

Slides 12_Risse.pdf

26 Review of TeV gamma-ray and neutrino data of relevance to UHECR

Speaker: Thomas Gaisser (University of Delaware)

Slides 17_Gaisser.pdf

11:00 Coffee break

Sources and Propagation

Convener: Dr Hiroyuki Sagawa (University of Tokyo)

27 Review of interpretation of multi-messenger data

Speaker: Guenter Sigl (University of Hamburg)

Slides 18_Sigl.pdf

28 Ultra High Energy Nuclei Propagation and the Spectrum of UHECR

We will discuss the main features of ultra high energy nuclei propagation in the intergalactic space, presenting a novel analytical approach to pursue such studies. We will also discuss a new interpretation of the experimental observations of UHECR.

Speaker: Dr Roberto Aloisio (INAF - Osservatorio Arcetri Firenze)

Slides 48_Aloisio.pdf

29 Transition from Galactic to Extragalactic Cosmic Rays and cosmic ray anisotropy

We constrain the energy at which the transition from Galactic to extragalactic cosmic rays occurs by computing the anisotropy at Earth of cosmic rays emitted by Galactic sources. Since the diffusion approximation starts to loose its validity for E/Z >10^(16-17) eV, we propagate individual cosmic rays using Galactic magnetic field models and taking into account both their regular and turbulent components. The turbulent field is generated on a nested grid which allows spatial resolution down to fractions of a parsec. If the primary composition is mostly light or intermediate around E ~ 10^18 eV, the transition at the ankle is ruled out, except in the unlikely case of an extreme Galactic magnetic field with strength >~ 10 {\mu}G. Therefore, the fast rising proton contribution suggested by KASCADE-Grande data between 10^17 eV and 10^18 eV should be of extragalactic origin. In case heavy nuclei dominate the flux at E >~ 10^18 eV, the transition energy can be close to the ankle, if Galactic cosmic rays are produced by sufficiently frequent transients as e.g. magnetars.

Speaker: Dmitri Semikoz (A)

Slides 28_Semikoz.pdf

12:50 Lunch break

Source models and theory challanges of UHECRs

Contributed talks 6x15+5 min

Convener: Prof. Paul Sommers (Penn State University)

30 Constraints on inductive acceleration of UHECRs in astrophysical sources.

I discuss possible sites of acceleration of UHECRs by regular electromagnetic fields in astrophysical sources. A plausible mechanism of acceleration works in the vicinity of supermassive black holes in active galactic nuclei. It is motivated by relatively high density of UHECR sources as suggested by both statistics of clustering and the shape of the GZK cutoff. However, I demonstrate that the model is strongly constrained by FERMI-LAT observations of the secondary gamma-ray background. I also briefly discuss potential Galactic sources where this mechanism might be at work.

Speaker: Sergey Troitsky (Russian Academy of Sciences (RU))

Slides 32_Troitsky.pdf

31 Deflection of ultra-high energy heavy nuclei in magnetic fields

In this work, we investigate the impacts a potential shift towards a heavy composition at the end of the spectrum would have on the future data. We present detailed simulations for the propagation of ultra-high energy heavy nuclei, with E > 60 EeV, within recent Galactic Magnetic Field (GMF) models. We both consider the regular and turbulent components of the GMF. We show that with UHE heavy nuclei, there is no one-to-one correspondence between the arrival directions of cosmic rays measured at Earth and the direction of their extragalactic sources. Sources can have several distorted images on the sky. We compute images of galaxy clusters and of the supergalactic plane in recent GMF models and show the challenges, but also the possibilities, of "UHECR astronomy" with heavy nuclei. Finally, we present a quantitative study of the impact of the GMF on the (de-)magnification of source fluxes, due to magnetic lensing effects. Such effects cannot be neglected in case of a heavy composition.

Speaker: Gwenael Giacinti (NTNU Trondheim, Norway)

Slides 65_Giacinti.pdf

32 Are UHECR and multiplet also galactic?

Since last decades UHECR models teach us that at EeV energy UHECR are mostly of extragalactic origin. Moreover earliest (2007) AUGER at 55 EeV energy events were suggesting an UHECR GZK cut off and arrival map correlated with super-galactic plane, SGP,inside the expected GZK volume traced by protons. However the same AUGER composition imprint favoured nuclei (heavy or light) and not nucleons. Finally last (2010) UHECR map fade any SGP correlation while earliest Cen A (nearest AGN source) correlation reinforsed and survived. Since early 2008 we interpret the signals as lightest He-like UHECR, that cannot fly more than few Mpc explaining Virgo absence and smeared Cen A unique traces. We foresaw (and now we observe) multiplets (at 20 EeV) by He fragments overlapping Cen A. We noted also a Vela triplet, eventual multiplet along Cen A; unexpected multiplet rose also along Magellanic stream. Therefore we ask the key question of present article: beyond Cen A may our galaxy and local group hide important sources, contrary to extra-galactic (GZK) UHECR models?

Speaker: Prof. Daniele Fargion (Rome University 1 Sapienza and INFN)

Slides 22_Fargion.pdf

33 Extragalactic and galactic sources: new evidence, new challenges, new opportunities

First, I will present new evidence, from gamma-ray observations of blazars, that cosmic rays are, indeed, accelerated in AGNs. Second, I will discuss the plausibility of a substantial contribution of transient galactic sources, such as past GRBs and hypernovae, to the observed flux of cosmic-ray nuclei. The likely contamination of UHECR data by the nuclei from past galactic stellar explosions creates new challenges for cosmic-ray astronomy. At the same time, it creates new opportunities for reconstructing galactic magnetic field and for "astro-archaeology". Finally, I will discuss some observational signatures of astrophysical nuclear accelerators.

Speaker: Alexander Kusenko (UCLA)

Slides 52_Kusenko.pdf

34 The Need for Hard Spectrum Local Sources of UHECR Nuclei

Using the recent Auger energy spectrum and composition analysis results, an investigation is carried out into the requirements placed on the UHECR sources. The spatial distribution of these sources is investigated along with the energy distribution of UHECR they output. These investigations reveal the need for local UHECR sources which output a hard spectrum of intermediate/heavy UHECR. These results demand that local (<80 Mpc) UHECR sources exist, placing exciting and difficult requirements on the local extragalactic candidate sources. None negligible (>0.01 nG) extragalactic magnetic fields are noted to further strengthen these results

Speaker: Dr Andrew Taylor (ISDC, University of Geneva)

Slides 96_Taylor.pdf

35 A strategy to unveil transient sources of ultra-high-energy cosmic rays

The origin of ultra-high-energy (UHE) cosmic rays (CRs) is still unknown and one of the biggest mysteries in modern astrophysics. The uncertainty of their composition makes this problem more complicated. If protons are dominant in UHECRs and are produced by phenomena related to astrophysical jets or outflows, there are few steady source candidates in local Universe which have luminosities enough to accelerate protons up to 10^{20} eV via statistical particle acceleration mechanisms. Since the few steady sources are difficult to reproduce isotropy observed by recent UHECR experiments, promising source candidates are astrophysical transients such as flares of active galactic nuclei and gamma-ray bursts. In this presentation we discuss how evidence of transient sources can be found and how future UHECR experiments can constrain transient source population of UHE protons.

Speaker: Hajime Takami (M)

Slides 37_Takami.pdf

16:00 Coffee break

New detection techniques and detector designs

Contributed talks 6x 15+5 min

Convener: Prof. Enrique Zas (University of Santiago)

36 Reconstruction of Muon Production Depth in grounded array based on the TTC (Time Track Complementarity) method

The muon longitudinal profile along the shower axis is strictly connected to the primary nature and primary hadronic interaction with air nuclei. The detection of muonic component inside showers generated by Very High Energy Cosmic Rays provides a very powerful tool for sensing high energy interactions between cosmic ray particles and air molecules. Fundamental parameters as the interaction cross section, inelasticity, hadron production and multiplicity can be measured comparing the development of shower electromagnetic component with that of muonic component. Since 1992 a method has been developed to combine the muon arrival direction in a ground based array for cosmic ray detection with their arrival delay respect to the shower axis in the shower core. This combination permits to select high energy muons weakly scattered from atmosphere and reconstruct their height of production with good accuracy. In this talk we discuss on the possibility to realize a “dual” apparatus able to detect both electromagnetic and muonic components at primary energy greater than 10^17.

Speaker: Dr Michelangelo Ambrosio (INFN Napoli)

Slides 47_Ambrosio.pdf

37 What the radio signal tells about the cosmic-ray air shower.

The physics of radio emission from cosmic-ray induced air showers is shortly summarized. It will be shown that the radio signal at different distances from the shower axis provides complementary information of the longitudinal shower evolution, in particular the early part, and the distribution of the electrons in the shower core. This complements the information obtained from surface, fluorescence, and muon detectors and is very useful in getting a comprehensive picture of an air shower.

Speaker: Prof. Olaf Scholten (KVI/Univ. of Groningen)

Slides 30_Scholten.pdf

38 Results from the Auger Engineering Radio Array

The Auger Engineering Radio Array (AERA) is one of the low energy enhancements of the Pierre Auger Observatory. AERA is based on experiences obtained with the LOPES and CODALEMA experiments in Europe and aims to study in detail the emission mechanism of radio signals in the MHz region from extensive air showers. The data from AERA will be used to assess the sensitivity of MHz radiation to the mass composition of cosmic rays and because of the energy threshold at 2 10{17} eV the dip region in the cosmic-ray flux spectrum can be studied in detail. We will present first results of AERA and of its prototypes.

Speaker: Ad van den Berg (University of Groningen)

Slides 95_vandenBerg.pdf

39 First results from the Microwave Air Yield Beam Experiment (MAYBE): measurement of GHz radiation for Ultra-High Energy Cosmic Rays detection

We present measurements of microwave emission from an electron-beam induced air plasma performed at the 3 MeV electron Van de Graaff facility of the Argonne National Laboratory. Results include the emission spectrum between 1 and 15 GHz, the polarization of the microwave radiation and the scaling of the emitted power with respect to beam intensity. MAYBE measurements provide further insight on microwave emission from extensive air showers as a novel detection technique for Ultra-High Energy Cosmic Rays.

Speaker: Mr Christopher Williams (University of Chicago & KICP)

Slides 92_Williams.pdf

40 Status of the microwave detection of cosmic rays program at the Pierre Auger Observatory

Radiation in the microwave band from the passage of charged particles through air has been detected in the laboratory. Applied to extensive air showers this radiation could provide a novel technique for ultra-high energy cosmic rays detection over large area, with 100% duty cycle and virtually no atmospheric attenuation. Detection in the GHz band is being actively pursued at the Pierre Auger Observatory. The status of microwave R&D activities at Auger will be reported, and in particular the design and performances of AMBER and MIDAS, two different prototypes of an imaging parabolic dish detector, will be reviewed.

Speaker: Pedro Facal San Luis (U)

Slides 51_Facal.pdf

41 Microwave emission from extensive air showers as seen by CROME

A measurement of extensive air showers in the microwave range has been considered as a possible successor to current measurement techniques. The CROME (Cosmic Ray Observation via Microwave Emission) experiment consisting of several parabolic antennas measures radiation from the atmosphere in coincidence with air showers detected by the KASCADE-Grande experiment. Nanosecond radio pulses are expected for vertical showers and thus, fast read-out electronics is used. Tens of KASCADE-Grande showers have crossed the field of view of our antennas after one year of data taking. A preliminary limit on microwave emission from air showers is presented.

Speaker: Radomir Smida (Karlsruhe Institute of Technology)

Slides smida-crome.pdf

42 TARA: Forward-Scattered Radar Detection of UHECR at the Telescope Array

Increased event statistics will be required to definitively answer the question of the origin(s) of Ultra-High Energy Cosmic Rays (UHECR). Using current technologies however, achieving the necessary statistics may be financially and practically impossible. We describe the status and plans of the TARA project, an effort to detect Ultra-High-Energy Cosmic Rays by their forward scattered or "bistatic" radar signature. Bistatic radar holds promise as a new remote sensing technique for UHECR, without the duty cycle limitations of nitrogen fluorescence detectors. Such a technique could prove key in advancing the study of UHECR beyond the constraints of the current generation of cosmic ray observatories. TARA consists of a low-VHF television transmitter illuminating the air above the Telescope Array (TA), and a set of radio receivers on the far side of TA approximately 50 km distant from the transmitter. We have collected radar data since April 2011 using a 2 kW transmitter at 54.1 MHz. Recently, we received permission to increase our broadcast power to 40 kW and our effective radiated power (ERP) to 6 MW. On the receiver end, we are employing software-defined radio receivers and developing real-time trigger algorithms based on the expected air shower radar echo. In addition to presenting an overview of the project status and future plans, we will present the most recent results of searches for coincidences between radar echoes and Telescope Array air shower events.

Speaker: Prof. John Belz (University of Utah)

Slides 74_Belz.pdf

19:45 Conference Dinner

19:45 departure from CERN by bus to Crown Plaza Hotel.
23:15 return by bus.

Thursday, 16 February

New detection techniques and detector designs

Contributed talks 6x 15+5 min

Convener: Piergiorgio Picozza (Dipartimento di Fisica(RomaII))

43 On the astrophysical value of larger, yet achievable UHECR detectors

The last decade has established UHECR physics as a phenomenologically rich and experimentally mature science. Key observations related to the UHECR energy spectrum, composition and distribution over the sky have clarified a few basic open question, and raised new, unexpected ones. The absence of a clear signal of anisotropy or correlation with some classes of astrophysical objects, although in line with some indications of the presence of heavy nuclei among the UHECRs, has raised doubts about the utility of pursuing the quest for the highest energy particles in the universe. We discuss why the quest should not stop now, and argue that expanding our observational capabilities at 10^20 eV is bound to give us key information. In particular, we show that the GZK effect remains our best ally to reduce the number of contributing sources to a handful, easier to separate on the sky, from which the deflection angular size, the source density, and thus the individual source power or UHECR energy budget can be obtained. This would be of tremendous value for the astrophysical understanding of UHECRs, of their sources and of their acceleration mechanism. An acceptance close to 10^6 km2 sr yr, with full sky coverage at 10^20 eV may thus be regarded as a high priority goal in astroparticle physics as well as high-energy astrophysics in general.

Speaker: Etienne Parizot (Université Paris Diderot / APC)

Slides 27_Parizot.pdf

44 Review of space-based approaches

The idea looking down the Earth to observe air-showers from space is not new. In fact, John Linsley already in 1979, has proposed to use a space telescope for the observation of UV emission from air-showers. Since then, a few missions are proposed to achieve this next generation technology for the exploration of the high energy universe. Space-based ultra-high energy observatories have important advantages compared with ground detectors: 1) the huge exposure area, 2) the well constrained distance to a shower, 3) the dust-free atmosphere in the above half troposphere, 4) the almost uniform exposure covering both hemispheres. Currently four space missions, dedicated to air-shower observation, have been proposed and planned by international collaborations of scientists and gencies, those are TUS (Tracking Ultra-violet Set up), JEM-EUSO (Extreme Universe Space Observatory on board Japanese Experiment Module), KLPVE, and Super-EUSO. In this presentation, I will review those missions and discuss a sound way to construct the solid basis of this new technology and possible collaborations between space and ground based facilities.

Speaker: Prof. Toshikazu Ebizusaki (Riken)

Slides 14_Ebizusaki.pdf

45 The JEM-EUSO mission: context and status

JEM-EUSO, the Extreme Universe Space Observatory on board the Japanese Experiment Module of the ISS (International Space Station), is expected, within this decade, to explore the ultra-high energy (UHE) Universe with unprecedentedly large effective area and uniform exposure. In this talk we first summarize the scientific context of the mission, including its scientific requirements, and we discuss its role in the framework of the development of next- generation UHE observatories. We then report 1) on the status of the instrument, describing the most recent technical developments; and 2) on the mission aspects of the observatory. In addition, the current programmatic status will be presented.

Speaker: Prof. Andrea Santangelo (University Tuebingen)

Slides 55_Santangelo.pdf

46 Performances of JEM-EUSO

Designed as the first mission exploring the Ultra High Energy Universe from space, JEM-EUSO will monitor the Earth's atmosphere to record UV (300-400 nm) tracks generated by Extensive Air Showers produced by UHECR primaries. In this contribution, the expected performances of JEM-EUSO will be reviewed. In particular, by detailed simulation studies performed with realistic trigger and reconstruction efficiencies, the observational duty cycle and rôle of clouds are calculated. The estimate of aperture and exposure, as well as of the expected angular, energy, and Xmax resolutions will be presented. In addition, the obtained performance will be discussed in the context of the scientific goals of the JEM-EUSO mission.

Speaker: Dr Mario Bertaina (University Torino)

Slides 56_Bertaina.pdf

47 Interdisciplinary Science with Large Aperture Cosmic Ray Detectors

Large aperture detector systems to measure high energy cosmic rays, also offer unique opportunities in other areas of science. Disciplines include geophysics such as seismic and volcanic activity, and atmospheric science ranging from clouds to lightening to aerosols to optical transients. This talk will discuss potential opportunities based on the ongoing experience of the Pierre Auger Observatory.

Speaker: Lawrence Wiencke (Colorado School of Mines)

Slides 69_Wiencke.pdf

11:00 Coffee break

New detection techniques and detector designs

Contributed talks 6x 15+5 min

Convener: Igor Tkachev (Russian Academy of Sciences (RU))

48 Ultra high energy particle physics and astrophysics. The need for multicomponent EAS measurement and primary particle identification.

We show that a fundamental element for future generations of UHECR observatories is the multicomponent measurements of extensive air shower. Such measurements may allow an event-by-event identification of the primary cosmic ray type and would radically impact on the study of various aspects of UHECR physics. From detailed hadronic physics studies to sources discovery via Galactic and extra-galactic magnetic fields determination and LIV tests we expose some of the expected progresses. We also present a promising detection system, based on the close integration of particles and microwave radio detectors, which allows, in principle, to measure separately the EM and muon cascade evolution of EAS. Our purpose is illustrated by presenting the progress of the EASIER upgrade currently underway at the Pierre Auger Observatory.

Speaker: Antoine Letessier-Selvon (LPNHE CNRS/In2p3)

Slides 36_Letessier-Selvon.pdf

49 A conceptual design for a large ground array of Fluorescence Detectors

In order to understand the composition and hadronic interactions of ultra-high energy cosmic rays above $10^19.5$ eV, currently limited by statistics, the next generation of experiments must provide a precise measurement of the maximum shower development with a large aperture. We propose a novel design of fluorescence detectors arranged in a large ($\ge 40000$ km$^2$) ground array. The shower reconstruction is obtained from the time development of the fluorescence signal only, with a significant simplification of the detector design and reduction of costs. Simulations of the conceptual design are presented.

Speaker: Prof. Paolo Privitera (University of Chicago)

Slides 90_Privitera.pdf

50 Future plans of the Telescope Array experiment

The Telescope Array (TA) experiment is the world’s first and the only air shower detector to be directly calibrated by an on-site accelerator beam. For wider and deeper understanding of cosmic rays via high precision measurements, we have several future plans for the TA experiment. One extension plan is called TA low energy extension (TALE), to extend the sensitive energy range to 10^16.5 eV in order to study the second knee of the cosmic ray spectrum and the galactic-extragalactic transition, and to characterize cosmic ray showers to compare with LHC measurements. TALE is an ongoing project. A second plan is to install a huge number of SDs and/or FDs in order to obtain the world's largest exposure and the finest accuracy to open a new window on astronomy with ultra high energy particles.

Speaker: Shoichi Ogio (Osaka City University)

Slides 78_Ogio.pdf

12:30 Lunch break

Summary and outlook

Convener: Johannes Bluemer (KIT)

51 Theory and phenomenology: summary & outlook

Speaker: Angela Olinto (The University of Chicago)

Slides 16_Olinto.pdf

52 Experimental summary & future prospects

Speaker: Prof. Masaki Fukushima (University Tokyo)

Slides 15_Fukushima.pdf

53 Open discussion

Speaker: Alan Watson (University of Birmingham (GB))

Slides 20_Lipari.pdf 20_Watson.pdf