Results from HiRes and Observation of the GZK Suppression Kai Martens High Energy Astrophysics...

Results from HiResand Observation of the

GZK Suppression

Kai Martens

High Energy Astrophysics Institute

Department of Physics, University of Utah

for the HiRes Collaboration

HR1HR2

August 7, 2007 Kai Martens, University of Utah, @ ISMD 2

Outline:- Short Introduction to Cosmic Rays

- The HiRes Experiment- Monocular Observation:

- Going to Extremes- Evidence for GZK Suppression

- Stereo Observation: - Checks and Balances- HiRes Composition Measurement

- Interpretation: - Ankle, Cutoff, and Cosmogenic Neutrinos- HiRes Neutrino Limits

- In Search of the Sources:- Anisotropy- Correlations

- Conclusions


Cosmic Rays

GeV TeV PeV EeV

(m2 s

r s

GeV

)-1

10-28

102

1km2 y/

Power laws for Flux: J~E

<3 PeV: =2.7~3 PeV: Knee>3 PeV: =3.0

Swordy Plot:

knee

ankle


Air Shower Dimensions

Fluorescence Detector:longitudinal profilethroughout atmosphere

Ground Array:transverse profileat ground level

Cosmic Ray showers - start at ~ 15 km above ground- span a couple of km across- hundreds of billions of particles

thick water tanks thin scintillators

1019 eV

(e/m + ) (e/m only)


The HiRes Experiment:

12.6 km apart

HR2: 12/199942 mirrors

3-31 elevationFADC (100ns)

DugwayProvingGrounds

HR1: 5/199719 mirrors

3-17elevationSample&Hold

Delta

HiRes on DPG:


HiRes Optics:

Mirror surface 5.1 m2

Field of view: 16 x 14

Camera:16 x 16

PMTeach sees

1o x 1o

in sky

SUN:½o

UV filter !!!(protecting PMTs)

low resolutionhigh speed


HiRes: Stereo!!!July 11, 1999; Energy: 19 EeV

Light Propagation:

Atmosphere HR1

HR2

HR2HR1

Dugway Proving Ground


The Collaboration:S. BenZvi, J. Boyer, B. Connolly, C.B. Finley, B. Knapp, E.J. Mannel, A. O’Neill, M. Seman, S. Westerhoff

Columbia University

J.F. Amman, M.D. Cooper, C.M. Hoffman, M.H. Holzscheiter, C.A. Painter, J.S. Sarracino, G. Sinnis, T.N. Thompson, D. Tupa

Los Alamos National Laboratory

J. Belz, M. Kirn

University of Montana

J.A.J. Matthews, M. Roberts

University of New Mexico

D.R. Bergman, G. Hughes, D. Ivanov, L. Perera, S.R. Schnetzer, L. Scott, S. Stratton, G.B. Thomson, A. Zech

Rutgers University

N. Manago, M. Sasaki

University of Tokyo

R.U. Abbasi, T. Abu-Zayyad, G. Archbold, K. Belov, A. Blake, O. Brusova, Z. Cao, W. Deng, W. Hanlon, P. Huentemeyer, C.C.H. Jui, E.C. Loh, K. Martens, J.N. Matthews, D. Rodriguez, K. Reil, J. Smith, P. Sokolsky, R.W. Springer, B.T. Stokes, S.B. Thomas, L. Wiencke

University of Utah

Z. Cao, B. Zhang, Y. Zhang, Y. Yang

IHEP Bejing


Challenge: (Mono) Reconstruction

angle along horizon

ang

le a

bo

ve h

ori

zon

In-plane Angle (deg)

Tim

e (1

00

ns)

angle in plane

Tim

e to

co

mm

on

sto

p

amount of matter (air) traversed

Ph

oto

elec

tro

ns

at d

etec

tor

light curve+

atmosphere=

energy

Reconstruction steps:

1. shower detector plane 2. Shower axis (full geometry)3. fluorescence light curve

(FADC !!!)


HiRes Monocular Spectra

flux x E3

HR1: longer exposure high energy

HR2: larger elevation coverage low energy

energy scale uncertainties:

- missing energy 5%- energy loss rate 10%- fluorescence yield 6%- atmospheric conditions 4%- photometric calibration10%

total (energy): 17%

flux uncertainty: 30% (@ =2.8)

data:HR1: 5/97-6/05HR2: 12/99-8/04


HR1: Aperture Verification - Data vs. MC


HR2: Aperture Verification - Data vs. MC


GZK Suppression: ? !!

Old plots:AGASAAGASA (E–20%)

avoid double counting:remove HR1 events that also

are in the HR2 data set

Broken power-law fits:a.) one vs. two breakpoints:

2 reduced by 23.4 4.5

b.) compare measured data to red line extrapolation:expect: 39.9observe: 13 4.8 (P=7x10-7)

Quacks like duck, don’t

it?


Stereo Observation

full stereo analysis ongoing; shown: geometry from HR1/HR2plane intersect, light curve from HR2 data only:

stereo advantages: geometry constraint (!!!), light balance check on atmosphere

energy balance:Xmax

resolution: 30g/mc2


Composition from Stereo DataXmax distributions:

datavs.

proton

datavs.iron

Xm

ax [g

/cm

2 ]

Xmax [g/cm2]

18 20

log10(E/eV)

Fe + p | (mostly) p

data: HRprototype

HiRes stereodata: ~ 80% p

MC: p

MC: Fe

galactic extra-galactic


Interpretation of HiRes monocular CR:

Doug Bergman, Rutgers(following Berezinsky)

Fit interprets spectrumin terms of

extragalactic protonsthat traveled from

cosmological sources

changed interpretation of ankle:

galactic/extragalactic transition: composition change vs. slope change

p+ (1232) +N

+

e + e +

composition change slope change

p+ p+e++e- redshift

energy

flu

x

propagation:protons

only


ee

eepn

HiRes Composition Guided Fits fluxsource model:

all sources inject with E

= 2.42uniform with redshiftevolution (1+z)m

m = 2.46

future: astronomy inspired redshift evolution

composition as measured !


The HiRes Neutrino Limits:

90% CL, uncertainty MC statistics only

MC injection: E-2 spectrum

e limits (no topography):1018 – 1019: 3820 ±1201019 – 1020: 3260 ±801020 – 1021: 4250 ±100

event distinguishing features: - horizontal !!! - close to ground

target mass: rockdetector volume: air

e LPM -lepton

limits:1018 – 1019: 420-20

+25

1019 – 1020: 1340-110+140

1020 – 1021: 29400-8900+22100

fluxes as derived from

HR spectrum fit


MC: Topology at Work interaction points for decaying above ground:Cedar Mtns

Deep Creek Rng

Stansbury Mtns Oquirrh Mtns

Fish Springs Rng Thomas Rng

Sheeprock Mtns

90 95

zenith angle in

HR system:


Anisotropy and ClusteringHR2 Sky Map:Sky Map: non-uniform exposure… use MC & on-time database to estimate uniform exposure

Point Sources:Point Sources:AGASA for E > 40 EeV: 5 doublets, 1 tripletHiRes stereo +AGASA: 28% of MC > tripletHiRes: E > 30 EeV: triplet + 1

Looking for Accelerators:Looking for Accelerators: BL lacTinyakov, Tkachev, Gorbunov analysis:

Vernon 9th, m<18, AGASA+Yakutsk: E>48 (24) EeV P=10-4

Vernon 10th, BL criteria differ, HiRes: E>10 EeV P=10-3

HiRes analysis (all events): 0.02%

the jury is still out: more data

Findings:- no global dipole- deficit at Galactic Anticenter??? (3.4)


Fixed Target Experiment @ 31018eV

HiRes 2007

mbsysstatAirpin )(11)(14460 HiRes:

meanenergy:

~ 1018.5 eV

“protons”selected

Xmax

Data:


Now Commissioning: Telescope Array

TA

3 x 120 degfluorescencetelescopes

MCCRCDelta, UT

2h from SLC

512 x 3m2

scintillatorarray


Conclusions• HiRes has finished taking data• HiRes has changed the cosmic ray (CR) landscape:

- extragalactic CR mostly protons- GZK suppression present in data + resonance- ankle likely e+e-, not transition to extragalactic…

spectral features important TALE• HiRes finds no significant UHE-CR anisotropies• HiRes finds no significant UHE-CR clustering• Correlations with astrophysical sources: jury still out• Ultra High Energy (UHE) CR research is alive in Utah:

Come and join our efforts for TA/TALE www.telescopearray.org

[email protected]


HiRes & Auger Limits

Results from HiRes and Observation of the GZK Suppression Kai Martens High Energy Astrophysics...

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