Particle Physics with High Energy Cosmic Rays Mário Pimenta Valencia, 10/2011.
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Transcript of Particle Physics with High Energy Cosmic Rays Mário Pimenta Valencia, 10/2011.
Particle Physics with High Energy Cosmic Rays
Mário Pimenta Valencia, 10/2011
Particle Physicse+
K+-
ee
u
bc
dt
s
γ, W+,W-, Z0 G1,, …., G8
H0 ?
Accelerators
Year of completion
Ene
rgy
(GeV
) The Large Hadron Collider (LHC)
~1930
~ 10 MeV
High Luminosity Sophisticated detectors
Central region Energy limited
14 TeV
Cosmic rays
Energy (eV)
Flu
x (m
2 sr
s G
eV)-1
LHC
Forward Region Extreme Energies
Small fluxes indirect measurements
John Linsley, 1962
100 TeV
Cosmic rays “rain”
Cosmic rays “rain”
Cosmic rays “rain”
Cosmic rays “rain”
Cosmic rays “rain”
Cosmic rays “rain”
Cosmic rays “rain”
Cosmic rays “rain”
Cosmic rays “rain”
Cosmic rays “rain”
Cosmic rays “rain”
P(Fe) Air Baryons (leading, net-baryon ≠ 0)
π0 ( π0 e+e- e+e- …)
π ± ( π ± ν ± if Ldecay< Lint )
K±, D. …
16
Shower detection
ΔX
Xmax = X1 + ΔX
Shower development
X1Xmax
em profilemuonic
profile
dXdX
dNe
E Ne
dXdX
dN
N
l
dxxlX0
)()(
South Hemisphere Area ~ 3000 km2
Nov 2009
60 km
Malargüe, Argentina
The Pierre Auger Observatory
24 fluorescence telescopes1600 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 (ni, ti):The directionThe core positionThe Energy
E.M. and signal at the SD
S(1000) contributions Individual time traces
Proton, ϴ =45º , E= 1019 eV , d= 1000m
The fluorescence detectors (FD)
The fluorescence detectors (FD)
The fluorescence detectors (FD)
Fluorescence detector measurements
Fly’s EyeE~3x1020 eV
)(tN
E Ne
The direction
Light profiles
(Xmax, Energy, …)
Xmax
A 4 eyes hybrid event !
Total Energy uncertainty: 22%
FD
SD
SD Energy Calibration
S38
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 × 1017 eV with full efficiency
The results
Energy spectrum
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 E3 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 accelerationCen A
E> 57 1018 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
Xmax distributions
ΔX
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%
Xmax distributions
As the energy increases the distributions become narrower !!!
<Xmax> and RMS(Xmax)
Heavy nuclei ? Wrong Physics models ?
γFe 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 …
<Xmax>
σ (Xmax)
: iron ; (1-): proton
Not possible to have just a two component model !
G. Wilk, Z. Wlodarczyk
Number of Inclined events Multivariate and Universality
A significant excess of Muons is observed that can not be explained by composition alone
N ~ E095
If just proton …
A dramatic increase in the proton-proton cross section around :
!!!TeV100s
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
Exotics @Auger….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 <Xmax > 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
0
5
10
15
20
25
0 200 400 600 800 1000 1200Time (hours)
Bac
kgro
und
C
urr
ent
(pA
cm
-2)
10
14
18
22
26
30
Tem
per
atu
re (
ºC)
0
5
10
15
20
25
0 200 400 600 800 1000 1200
10
14
18
22
26
30
Background currentBackground current converted to 23 ºCTemperature
At a constant temperature the current is stable, demonstrating the operation of the chamber at a very low gas
flow.
External view of the 0.5x1m2 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 ~ 5o
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 array Hamamatsu array
Towards a FS with SiPM
1440 pixels, 4.5 degree FOV
FACTFirst 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 2011-090N in Golden Hybrid events
N ~ E094 ~ flat dependence with cos2ϴ
Not p
ublic
!!!
These data are not consistent neither with a composition change scenario nor with the EPOS enhancement mechanism
N in Kascade Grande
E ~ 1016-18 eV
Data lies between models expectations for p and Fe
<Xmax> from SD
Asymmetry of Signal risetime
<sec(θmax)> <Xmax> !!!
< sec(θmax)> (E)
t tt
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 tg
All delays
z
rctg
2
2
1
500 m
Above 500 m the geometric delay is clearly dominant !!!
ϴ = 600
0o
“em” background
60o
If reduced by a factor ≈ 10 and if better time resolution
r > 500 m ???
Ө > 30o ???
E > 2 1018 eV ??? (cross-check with AMIGA)