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Takashi Sako (STE lab/KMI, Nagoya University) for the LHCf collaboration HEAP 2011, 13-15 Nov. 2011, KEK 1

0g/cm 2

Uncertainty in hadronic interaction

Xmax

Deep in the atmosphere

Proton shower and nuclear shower of same total energy 10 18 10 19 Pierre Auger Observatory (PAO) 2

0g/cm 2

Uncertainty in hadronic interaction

Xmax

Deep in the atmosphere

Proton shower and nuclear shower of same total energy 10 18 10 19 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

√s=14TeV

The LHC forward experiment

LHCf Detector(Arm#1)

ATLAS

E lab =10 17 eV

140m Two independent detectors at either side of IP1 ( Arm#1, Arm#2 )

LHCf Detector(Arm#2)

Beam Beam pipe Charged particles (+)

Neutral particles

Charged particles (-)

96mm

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

K.Yoshida

Kobayashi-Maskawa Institute, Nagoya University, Japan Shibaura Institute of Technology, Japan

K.Kasahara, Y.Shimizu, T.Suzuki, S.Torii

Waseda University, Japan

T.Tamura

M.Haguenauer

Kanagawa University, Japan 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

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

Event category of LHCf

Leading baryon (neutron) LHCf calorimeters Single hadron event Multi meson production π 0 photon Single photon event π 0 photon Pi-zero event (photon pair) 10

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 10 5 shower events in Arm1+Arm2 With Stable Beam at √s = 7 TeV (E lab  = 2.5x10

16 Total of 150 hours for physics with different setups eV)  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 2014 12

TeV Gamma not only from Crab but Underground!

Longitudinal development Energy Determination !

Silicon X Lateral development Position Determination Silicon Y

Event sample measured by Arm2 at 30 March 2010

Particle Identification

 PID (EM shower selection) – – Select events

ε and P for hadron hadron EM L 90% L 90% 14

 

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 zero degree 15

Comparison with Models

Adriani et al., PLB, 2011

DPMJET 3.04 QGSJET II-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145

π

identification

Longitudinal development Cal.

Event sample in Arm2

Cal.

Lateral development Silicon X Silicon Y

• • • A Pi0 candidate event 599GeV & 419GeV photons in 25mm and 32mm tower, respectively M = θ√(E 1 xE 2 )



1 (E 1 )



2 (E 2 )



140 m 140m



I.P.1

Invariant mass of photon pairs Comparison with models, in progress 17

π 0

Analysis more…

Original Idea New Analysis!

π

spectrum and air shower

QGSJET II original Artificial modification X=E/E 0 Ignoring X>0.1 meson π 0 spectrum at E lab = 10 19 eV

   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

Longitudinal AS development 30g/cm 2

10 2

900GeV Analysis

(Next target to publication) 10 2 100 200 300 400 500    Entry normalization No PID bias correction Ongoing works • Luminosity normalization • PID correction • Systematics study • Increasing MC statistics , etc… 100 200 400 Data DPMJET 3.04

QGSJET II-03 SIBYLL 2.1

PYTHIA 8.146

EPOS 1.99

500 20