Takashi Sako (STE lab/KMI, Nagoya University)
for the LHCf collaboration
HEAP 2011, 13-15 Nov. 2011, KEK
1
Uncertainty in hadronic interaction
0g/cm2
Xmax
Deep in the
atmosphere
Proton shower and nuclear
shower of same total energy
1018
1019
Pierre Auger Observatory (PAO)
2
Uncertainty in hadronic interaction
0g/cm2
Xmax
Deep in the
atmosphere
Proton shower and nuclear
shower of same total energy
1018
1019
Pierre Auger Observatory (PAO)
Constraints from accelerator experiments indispensible
3
What should be measured at colliders
multiplicity and energy flux at LHC 14TeV collisions
pseudo-rapidity; η= -ln(tan(θ/2))
Multiplicity
Energy Flux
All particles
neutral
Most of the energy flows into very forward
4
The LHC forward experiment
√s=14TeV
LHCf Detector(Arm#1)
ATLAS
Elab=1017eV
140m
Two independent detectors at
either side of IP1 ( Arm#1, Arm#2 )
LHCf Detector(Arm#2)
Beam
Beam pipe
Charged particles (+)
Neutral
particles
96mm
Charged particles (-)
5
The LHCf Collaboration
K.Fukatsu, T.Iso, Y.Itow, K.Kawade, T.Mase, K.Masuda, Y.Matsubara,
G.Mitsuka, Y.Muraki, T.Sako, K.Suzuki, K.Taki
Solar-Terrestrial Environment Laboratory, Nagoya University, Japan
H.Menjo
Kobayashi-Maskawa Institute, Nagoya University, Japan
K.Yoshida
Shibaura Institute of Technology, Japan
K.Kasahara, Y.Shimizu, T.Suzuki, S.Torii
Waseda University, Japan
T.Tamura
Kanagawa University, Japan
M.Haguenauer
Ecole Polytechnique, France
W.C.Turner
LBNL, Berkeley, USA
O.Adriani, L.Bonechi, M.Bongi, R.D’Alessandro, M.Grandi, P.Papini,
S.Ricciarini, G.Castellini
INFN, Univ. di Firenze, Italy
K.Noda, A.Tricomi
J.Velasco, A.Faus
A-L.Perrot
INFN, Univ. di Catania, Italy
IFIC, Centro Mixto CSIC-UVEG, Spain
CERN, Switzerland
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LHCf Detectors
 Imaging sampling shower calorimeters
 Two independent calorimeters in each detector (Tungsten 44r.l.,
1.6λ, sample with plastic scintillators)
Arm#1 Detector
20mmx20mm+40mmx40mm
4 XY SciFi+MAPMT
Arm#2 Detector
25mmx25mm+32mmx32mm
4 XY Silicon strip detectors
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8
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Event category of LHCf
Leading baryon
(neutron)
LHCf calorimeters
Single hadron
event
Multi meson production
photon
π0
π0
photon
Single photon
event
Pi-zero event
(photon pair)
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Expected Results at 14 TeV Collisions
(MC assuming 0.1nb-1 statistics)
Detector response
not considered
Operation 2009-2010
With Stable Beam at √s = 900 GeV
 Total of 42 hours for physics
 About 105 shower events in Arm1+Arm2
With Stable Beam at √s = 7 TeV (Elab = 2.5x1016 eV)
 Total of 150 hours for physics with different setups
 Different vertical position to increase the accessible kinematical range
 Runs with or without beam crossing angle
 ~ 4x108 shower events in Arm1+Arm2
 ~ 106 π0 events in Arm1 and Arm2
Status
 Completed program for 900 GeV and 7 TeV
 Removed detectors from tunnel in July 2010
 Post-calibration beam test in October 2010
 Upgrade to more rad-hard detectors for 14TeV in 2014
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TeV Gamma not only from Crab
but Underground!
Longitudinal
development
Lateral development
Silicon X
!
Energy
Determination
Position
Determination
Silicon Y
Event sample measured by Arm2 at 30 March 2010
Particle Identification

PID (EM shower selection)
– Select events <L90% threshold and multiply P/ε
ε (photon detection efficiency) and P (photon purity)
– By normalizing MC template L90% to data, ε and P for
certain L90% threshold are determined.
hadron
EM
EM
hadron
EM
L90%
L90%
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Photon spectra at
√s=7TeV collisions
(Adriani et al., PLB, 2011)


Spectra of Arm1&2 at common η
σine = 71.5mb assumed; consistent with the other LHC
experiments
zero degree
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Comparison with Models
Adriani et al., PLB, 2011
DPMJET 3.04 QGSJET II-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145
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π0 identification
Longitudinal development
Large
SmallEvent sample in Arm2
Cal.
Cal.
• A Pi0 candidate event
• 599GeV & 419GeV photons in 25mm
and 32mm tower, respectively
• M = θ√(E1xE2)
Lateral development
Silicon X
1(E1)
R
R
140 m
140m
Silicon Y
2(E2)
Invariant mass of photon pairs
=

I.P.1
Comparison with models, in progress17
0
π
Analysis more…
Original
Idea
New Analysis!
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π0 spectrum and air shower
QGSJET II original
Artificial modification
X=E/E0
Ignoring X>0.1 meson
π0 spectrum at Elab = 1019eV



Longitudinal AS development
Artificial modification of meson
spectra and its effect to air
shower
Importance of E/E0>0.1 mesons
Playing at LHC energy within
reasonable modification range
30g/cm2
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900GeV Analysis
(Next target to publication)
102
102
100
200
300Energy
400(GeV)
500
 Entry normalization
 No PID bias correction
 Ongoing works
• Luminosity normalization
• PID correction
• Systematics study
• Increasing MC statistics , etc…
100
200
300
400(GeV)
500
Energy
Data
DPMJET 3.04
QGSJET II-03
SIBYLL 2.1
PYTHIA 8.146
EPOS 1.99
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Experimental Plan

14TeV p-p collisions (Elab=1.0x1017eV)
• Assured in 2014

LHC p-Pb collisions
• In discussion for 2012

RHIC 500GeV p-p collisions
• Starting discussion

LHC/RHIC (p,C,Fe)-CNO collisions
21
Experimental Plan

14TeV p-p collisions (Elab=1.0x1017eV)
• Assured in 2014 --- highest energy

LHC p-Pb collisions
• In discussion for 2012

RHIC 500GeV p-p collisions
• Starting discussion

LHC/RHIC (p,C,Fe)-CNO collisions
22
Experimental Plan

14TeV p-p collisions (Elab=1.0x1017eV)
• Assured in 2014 --- highest energy

LHC p-Pb collisions
• In discussion for 2012 --- nuclear effect

RHIC 500GeV p-p collisions
• Starting discussion

LHC/RHIC (p,C,Fe)-CNO collisions
23
Experimental Plan

14TeV p-p collisions (Elab=1.0x1017eV)
• Assured in 2014 --- highest energy

LHC p-Pb collisions
• In discussion for 2012 --- nuclear effect

RHIC 500GeV p-p collisions
• Starting discussion --- energy dependence

LHC/RHIC (p,C,Fe)-CNO collisions
24
Experimental Plan

14TeV p-p collisions (Elab=1.0x1017eV)
• Assured in 2014 --- highest energy

LHC p-Pb collisions
• In discussion for 2012 --- nuclear effect

RHIC 500GeV p-p collisions
• Starting discussion --- energy dependence

LHC/RHIC (p,C,Fe)-CNO collisions
• Dream! Before my retirement…
25
Related to CTA???
Related to CTA???
Proton : E-2 (<512TeV)
Beam (3° FWHM)
0°
5°
20°
10°
Karlsson and Kamae, ApJ 674, 278-285 (2008)
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Summary


LHCf successfully took data at LHC 0.9
and 7TeV p-p collisions
First analysis results for photon spectra
 None of the models can fit the data, but the
data is within model diversity



Further analysis on going
Variety of future experiments are
assured and in discussion
Possible relation to CTA physics?
28
Backup
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Secondary in
Hadron Interaction
Multi meson production
(High energy)
π0
π+
(Low energy)
π-
Leading baryons
γ
μ
proton / neutron
Next interaction
EM shower
33
LHCf can measure
Multi meson production
(High energy)
π0
π+
(Low energy)
π-
Leading baryons
γ
μ
proton / neutron
Next interaction
EM shower
34
Key measurements in colliders
E0
EM
shower
E leading baryon
Elasticity / inelasticity
Total cross section
(TOTEM at LHC)
Meson Multiplicity
Forward spectra
Air shower experiments
Astrophysical parameters
- source type
- source distribution
- source spectrum
- source composition
Primary CR
- propagation
- energy
- chemical composition
- direction
Observations
- lateral distribution
- longitudinal distribution
- particle type
- arrival timing
Air shower experiments
Astrophysical parameters
- source type
- source distribution Primary CR
- energy
- source spectrum
- source composition - chemical composition
- direction
- propagation
Air shower development
- interaction
- atmosphere
Observations
- lateral distribution
- longitudinal distribution
- particle type
- arrival timing