Takashi Sako (STE lab/KMI, Nagoya University) for the LHCf collaboration HEAP 2011, Nov. 2011, KEK 1

Uncertainty in hadronic interaction 2 PROTON IRON g/cm 2 Xmax Proton shower and nuclear shower of same total energy Pierre Auger Observatory (PAO) Deep in the atmosphere

Uncertainty in hadronic interaction 3 PROTON IRON g/cm 2 Xmax Proton shower and nuclear shower of same total energy Pierre Auger Observatory (PAO) Deep in the atmosphere Constraints from accelerator experiments indispensible

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 5 96mm ATLAS 140m LHCf Detector(Arm#1) Two independent detectors at either side of IP1 ( Arm#1, Arm#2 ) Charged particles (+) Beam Charged particles (-) Neutralparticles LHCf Detector(Arm#2) Beam pipe √s=14TeV E lab =10 17 eV

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 INFN, Univ. di Catania, Italy J.Velasco, A.Faus IFIC, Centro Mixto CSIC-UVEG, Spain A-L.Perrot CERN, Switzerland The LHCf Collaboration 6

LHCf Detectors Arm#1 Detector 20mmx20mm+40mmx40mm 4 XY SciFi+MAPMT Arm#2 Detector 25mmx25mm+32mmx32mm 4 XY Silicon strip detectors Imaging sampling shower calorimeters Two independent calorimeters in each detector (Tungsten 44r.l., 1.6λ, sample with plastic scintillators) 7

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Event category of LHCf 10 π0π0 photon Pi-zero event (photon pair) Single photon event Leading baryon (neutron) Multi meson production Single hadron event LHCf calorimeters π0π0 photon

Expected Results at 14 TeV Collisions (MC assuming 0.1nb -1 statistics) Detector response not considered

Operation With Stable Beam at √s = 900 GeV  Total of 42 hours for physics  About 10 5 shower events in Arm1+Arm2 With Stable Beam at √s = 7 TeV (E lab = 2.5x10 16 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  ~ 4x10 8 shower events in Arm1+Arm2  ~ 10 6 π 0 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

TeV Gamma not only from Crab but Underground! Event sample measured by Arm2 at 30 March 2010 ! Energy Determination Position Determination Longitudinal development Lateral development Silicon X Silicon Y

Particle Identification PID (EM shower selection) – Select events <L 90% threshold and multiply P/ε ε (photon detection efficiency) and P (photon purity) – By normalizing MC template L 90% to data, ε and P for certain L 90% threshold are determined. 14 EM hadron EM L 90%

Photon spectra at √s=7TeV collisions (Adriani et al., PLB, 2011) Spectra of Arm1&2 at common η σ ine = 71.5mb assumed; consistent with the other LHC experiments 15 zero degree

16 Comparison with Models DPMJET 3.04 QGSJET II-03 SIBYLL 2.1 EPOS 1.99 PYTHIA Adriani et al., PLB, 2011

π 0 identification A Pi0 candidate event 599GeV & 419GeV photons in 25mm and 32mm tower, respectively M = θ√(E 1 xE 2 ) 17 Event sample in Arm2 Longitudinal development Lateral development Silicon X Silicon Y Small Cal. Large Cal. I.P.1   1 (E 1 )  2 (E 2 ) 140m R Invariant mass of photon pairs Comparison with models, in progress

π 0 Analysis more… 18 Original Idea New Analysis!

π 0 spectrum and air shower Artificial modification of meson spectra and its effect to air shower Importance of E/E 0 >0.1 mesons Playing at LHC energy within reasonable modification range 19 π 0 spectrum at E lab = eV QGSJET II original Artificial modification Longitudinal AS development Ignoring X>0.1 meson X=E/E 0 30g/cm 2

900GeV Analysis (Next target to publication) 20 Entry normalization No PID bias correction Ongoing works Luminosity normalization PID correction Systematics study Increasing MC statistics, etc… Preliminary Energy (GeV) Energy (GeV) 10 2 Data DPMJET 3.04 QGSJET II-03 SIBYLL 2.1 PYTHIA EPOS 1.99

Experimental Plan  14TeV p-p collisions (E lab =1.0x10 17 eV) 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 (E lab =1.0x10 17 eV) Assured in 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 (E lab =1.0x10 17 eV) Assured in highest energy  LHC p-Pb collisions In discussion for nuclear effect  RHIC 500GeV p-p collisions Starting discussion  LHC/RHIC (p,C,Fe)-CNO collisions 23

Experimental Plan  14TeV p-p collisions (E lab =1.0x10 17 eV) Assured in highest energy  LHC p-Pb collisions In discussion for 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 (E lab =1.0x10 17 eV) Assured in highest energy  LHC p-Pb collisions In discussion for 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???

27 0° 5° 10° 20° Proton : E -2 (<512TeV) Beam (3° FWHM) Karlsson and Kamae, ApJ 674, (2008)

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 29

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33 Leading baryons Multi meson production (High energy) (Low energy) Secondary in Hadron Interaction proton / neutron π0π0 π+π+ π-π- γ EM shower Next interaction μ

34 Leading baryons Multi meson production (High energy) (Low energy) LHCf can measure proton / neutron π0π0 π+π+ π-π- γ EM shower Next interaction μ

Key measurements in colliders E leading baryon Elasticity / inelasticity Meson Multiplicity Total cross section (TOTEM at LHC) EM shower E0E0 Forward spectra

Air shower experiments Astrophysical parameters - source type - source distribution - source spectrum - source composition - propagation Observations - lateral distribution - longitudinal distribution - particle type - arrival timing Primary CR - energy - chemical composition - direction

Air shower experiments Astrophysical parameters - source type - source distribution - source spectrum - source composition - propagation Observations - lateral distribution - longitudinal distribution - particle type - arrival timing Primary CR - energy - chemical composition - direction Air shower development - interaction - atmosphere