Particle Physics with High Energy Cosmic Rays Mário Pimenta Valencia, 10/2011

Particle Physics e+e+ K +- γ, W +,W -, Z 0 G 1,, …., G 8 H 0 ?

Accelerators Year of completion Energy (GeV) The Large Hadron Collider (LHC) ~1930 ~ 10 MeV High Luminosity Sophisticated detectors Central region Energy limited 14 TeV

Cosmic rays Energy (eV) Flux (m 2 sr s GeV) -1 LHC Forward Region Extreme Energies Small fluxes indirect measurements John Linsley, TeV

Cosmic rays “rain”

P(Fe) Air  Baryons (leading, net-baryon ≠ 0)  π 0 ( π 0    e + e - e + e -  …)  π ± ( π ±  ν  ± if L decay < L int )  K ±, D. …

16 Shower detection

ΔXΔX X max = X 1 + ΔX Shower development X1X1 X max em profile muonic profile E  Ne  N N 

South Hemisphere Area ~ 3000 km2 Nov km Malargüe, Argentina The Pierre Auger Observatory 24 fluorescence telescopes 1600 water Cerenkov detectors

1.5 km

telescope building “Los Leones” LIDAR station communication tower

telescope building “Los Leones” LIDAR station communication tower

Ground array measurements v ~ c From (n i, t i ): The direction The core position The Energy

E.M. and  signal at the SD S(1000) contributionsIndividual time traces Proton, =45 º, E= eV, d= 1000m

The fluorescence detectors (FD)

Fluorescence detector measurements Fly’s Eye E~3x10 20 eV E  Ne  The direction Light profiles (X max, Energy, …) X max

A 4 eyes hybrid event !

Total Energy uncertainty: 22% FD SD SD Energy Calibration S 38

Exposure Auger has already more than 10 times the Agasa Exposure

AMIGA/HEAT 23.5 km2, 42 extra SDs on 750m grid (infill array) associated with 30m2 buried scintillators, 3 extra FD telescopes tilted upwards 30 E ~ 3 × eV with full efficiency

The results

Energy spectrum

Ankle GZK like suppression !!! p  2.7K Δ π N

Kotera &Olinto Energy spectrum (interpretation ) Dip (Berezinsky et al) : p γ → p e + e - Spectrum of UHECRs multiplied by E 3 observed by HiRes I and Auger. Overlaid are simulated spectra obtained for different models of the Galactic to extragalactic transition and different injected chemical compositions and spectral indices, s. GZK: p γ →  → p N

Correlation with AGNs 28 out of 84 correlates P = 0.006, f = 33 ± 5% Vernon-Cetty-Vernon AGN catalog

Closest (4.6 Mpc) powerful radio galaxy with characteristics jets and lobes, candidate for UHECR acceleration Cen A E> eV But particles with the same rigidity (E/Z) follows the same paths !!! Lower energies No significant anisotropies scenarios in which high energy anisotropies are caused by heavy primaries and having a significant light component at lower energies are disfavoured

X max distributions ΔXΔX

Proton cross- section Slightly lower than expected by most of the models but in good agreement with recent LHC data. If % p > 20%, % He < 25%

X max distributions As the energy increases the distributions become narrower !!!

and RMS(X max ) Heavy nuclei ? Wrong Physics models ? γ Fe p

But if just proton and iron …  : iron fraction ; (1-  ): proton fraction

But if just proton and iron …  : iron fraction ; (1-  ): proton fraction

But if just proton and iron …  : iron fraction ; (1-  ): proton fraction

But if just proton and iron …  : iron fraction ; (1-  ): proton fraction

But if just proton and iron …  : iron fraction ; (1-  ): proton fraction

But if just proton and iron …  : iron fraction ; (1-  ): proton fraction

But if just proton and iron …  : iron fraction ; (1-  ): proton fraction

But if just proton and iron …  : iron fraction ; (1-  ): proton fraction

But if just proton and iron …  : iron fraction ; (1-  ): proton fraction

But if just proton and iron …  : iron fraction ; (1-  ): proton fraction

But if just proton and iron …  : iron fraction ; (1-  ): proton fraction

But if just proton and iron … σ (Xmax)  : iron ; (1-  ): proton Not possible to have just a two component model ! G. Wilk, Z. Wlodarczyk

Number of  Inclined eventsMultivariate and Universality A significant excess of Muons is observed that can not be explained by composition alone N  ~ E 095

If just proton … A dramatic increase in the proton-proton cross section around : R.Ulrich Reduced statistics

The grey disk model J. Dias de Deus et al. Hep-ph: 80 % Increase ! Black Disk R Ω A fast transition to the black disk at √s ~ 100 TeV can accommodate an ~ 80% increase in the total cross-section

Low flux Limited detector capabilities But a unique energy window! Double Bangs Cloudy day !!!

In favour of a Particle Physics solution  Ankle related to GZK if proton  No anisotropy at lower energies from Cen A region  A proton/iron model does not explain simultaneously the and σ (Xmax) data  The Nb of observed muons is quite above the expectations  The Nb of muons grows like what is expected for a single component composition We do need:  Higher statistics to be able to perform more sophisticated analyses  An upgrade of Auger South to enhance at least the muon sensitivity covering the entire array

“autonomous”RPCs At a constant temperature the current is stable, demonstrating the operation of the chamber at a very low gas flow. External view of the 0.5x1m 2 prototype Structure of the prototype Generic RPC architecture Background current at a gas flow of 1 kg/year of R134a. Resistive Plate Chambers (RPCs) are rugged and reliable gaseous detectors, widely used in High Energy and Nuclear Physics experiments. - excellent time resolution - can be produced in large areas - cheap

Under an absorber... 2 plane “telescope” To discriminate straight pointing trajectories from the shower axis PMT µ e µ e “em” supression 1.20 m 0.10 m ~ 5 o

An array of Geiger avalanche photodiodes Measurement of a “Dolgoshein” prototype PMT typ. peak PDE 25% SiPM could reach ~60% SiPM getting better (higher PDE, lower dark noise, lower crosstalk,…) and cheaper New packages (denser) being released Zecotek arrayHamamatsu array Towards a FS with SiPM 1440 pixels, 4.5 degree FOV FACT First G-APD Cherenkov Telescope Collaboration LIP, Aachen, MPI, Granada, Palermo, to develop a SiPM based Focal Surface Microscope view of a SiPM SiPM 50  m

We are exploring the 100 TeV energy scale, well beyond LHC, and may be we are touching something fundamental!

Maximo Ave GAP N  in Golden Hybrid events N  ~ E 094 ~ flat dependence with cos 2 Not public !!! These data are not consistent neither with a composition change scenario nor with the EPOS enhancement mechanism

N  in Kascade Grande E ~ eV Data lies between models expectations for p and Fe

from SD Asymmetry of Signal risetime  !!! (E)

tt t z Muon Production Depth (MPD) Reconstruct the MPD from the measured time traces at each SD detectors L. Cazon, R.A. Vazquez, A.A. Watson, E. Zas, Astropart.Phys.21:71-86 (2004) L.Cazon, PhD Thesis (USC 2005)

Muon time delays Geometric delay    Z r c t g All delays 500 m Above 500 m the geometric delay is clearly dominant !!! = 60 0

0o0o “em” background 60 o If reduced by a factor ≈ 10 and if better time resolution r > 500 m ??? Ө > 30 o ??? E > eV ??? (cross-check with AMIGA)