LHCf: very forward LHCf: very forward measurement of measurement of
neutral particles at neutral particles at LHCLHC
SAKO TakashiSAKO Takashi(for the LHCf collaboration)(for the LHCf collaboration)
Solar-Terrestrial Environment Solar-Terrestrial Environment Laboratory, Laboratory,
Nagoya University, JapanNagoya University, JapanHERA and the LHC @ CERN 28-May-2008
OutlineOutline
HECR observations and interaction HECR observations and interaction modelsmodels• GZK energy (absolute energy scale, GZK energy (absolute energy scale,
composition)composition)• Galactic cosmic-rays (composition)Galactic cosmic-rays (composition)
The LHCf experimentThe LHCf experiment• Experiment setupExperiment setup• Model discriminationModel discrimination
Energy spectrum of CRsEnergy spectrum of CRs
Engel, Nuclear Phys. B (Proc. Suppl.) 151 (2006) 437-461
Knee; acceleration limit of galactic CRs?
GZK cutoff; Propagation limit due to CMB
Berezinsky, ICRC 2007Berezinsky, ICRC 2007
AGASA X0.9 HiRes X1.2Yakutsk X0.75 Auger X1.2 (not enough)
Systematics of AGASA Total ±18% Hadron interaction (QGSJET, SIBYLL) ~10% (Takeda et al., 2003)
CompositioCompositionn
(Auger) (Auger)
Xmax favors heavy primary
Anisotropy favors light primary (if accept AGN correlation)
4
Composition of Galactic CRsComposition of Galactic CRs(KASCADE)(KASCADE)
QGSJET01
SIBYLL 2.1
Energy spectrum of CRsEnergy spectrum of CRs
Engel, Nuclear Phys. B (Proc. Suppl.) 151 (2006) 437-461
Knee; acceleration limit of galactic CRs?
GZK cutoff; Propagation limit due to CMB
LHC pp collision
Pseudo rapidity in LHCPseudo rapidity in LHC
pseudorapidity : = - ln (tan /2)
The CMS and TOTEM diffractive and forward physics working group
Tra
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erse
en
erg
y fl
ow
En
erg
y fl
ow
LHCf
LHCfLHCf
interaction point 1
140m
96mm
Arm#1
Arm#2
Installation of the detectors in the Installation of the detectors in the TAN absorbers at 140m from IP1TAN absorbers at 140m from IP1
96 mm
LHCf
LHCf (ZDCs) AcceptanceLHCf (ZDCs) Acceptance~10cmX10cm at 140m away fr
om collision point(5cm/140m ~ 300 urad)η> 8.4
η> 8.7
XF 0.1 1.0
K.Fukui, Y.Itow, T.Mase, K.Masuda, Y.Matsubara, H.Menjo, T.Sako, K.Taki, H.Watanabe Solar-Terrestrial Environment Laboratory, Nagoya University, Japan
K.Yoshida Shibaura Institute of Technology, Japan
K.Kasahara, M.Mizuishi, Y.Shimizu, S.Torii Waseda University, Japan
T.Tamura Kanagawa University, Japan
Y.Muraki Konan University
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, A. Viciani INFN, Univ. di Firenze, Italy
A.Tricomi INFN, Univ. di Catania, Italy
J.Velasco, A.Faus IFIC, Centro Mixto CSIC-UVEG, Spain
D.Macina, A-L.Perrot CERN, Switzerland
The LHCf experimentThe LHCf experiment
Double Arm DetectorsDouble Arm Detectors
Arm#1 Detector Arm#2 Detector90mm
290mm
Double Arm DetectorsDouble Arm Detectors
Arm#1 Detector20mmx20mm+40mmx40mm4 XY SciFi+MAPMT
Arm#2 Detector25mmx25mm+32mmx32mm4 XY Silicon strip detectors
Model dependence in Model dependence in LHCfLHCf
Gamma-ray spectra expected in a 1000 sec operation of LHCf at very low LHC luminosity ( 1029cm-2s-1 )
θ~ 0 radian θ~ 270 μradian
ππ0 0 spectraspectra
QGSJETII ⇔ DPMJET3χ2= 106 (C.L. <10-6) ⇔ SIBYLL χ2= 83 (C.L. <10-6)DPMJET3 ⇔ SIBYLL χ2= 28 (C.L.= 0.024) 107events DOF = 17-2=15
Pi zero produced at collision can be extracted by using gamma pair eventsPowerful to eliminate beam-gas BG
Neutron spectraNeutron spectra
Energy spectra at detector front Resolution included spectra
Drescher, Physical Review D77, 056003 (2008)
New modelsNew models(PICCO, (PICCO, EPOS)EPOS)
Neutron Pi0
Proton
LPM effectLPM effect
Transition curve of a 1 TeV photon w/ and w/o LPM to be measured by LHCf
○ w/o LPM■ w/ LPM
Run scheduleRun schedule
LHCf runs will be carried out during the LHCf runs will be carried out during the LHC commissioning with low luminosity LHC commissioning with low luminosity L<10L<103030cmcm-2-2ss-1-1
Data taking at 10TeV collisions in 2008 Data taking at 10TeV collisions in 2008 and 14TeV collisions in 2009and 14TeV collisions in 2009
Dedicated run with beam crossing angle Dedicated run with beam crossing angle in under discussion (pseudo-rapidity in under discussion (pseudo-rapidity limit 8.7 => 8.4)limit 8.7 => 8.4)
Future runs during ion collisions in studyFuture runs during ion collisions in study
SummarySummary Interpretation of CR observation data in Interpretation of CR observation data in
10101515-10-102020eV strongly depends on the eV strongly depends on the interaction model used in the analysis.interaction model used in the analysis.
LHCf will set a crucial calibration point at LHCf will set a crucial calibration point at 10101717eV for the interaction models.eV for the interaction models.
LHCf can measure E, p spectra of LHCf can measure E, p spectra of gamma-rays, πgamma-rays, π00 and neutrons at η>8.7 and neutrons at η>8.7 (8.4).(8.4).
LHCf can clearly discriminate LHCf can clearly discriminate existing/proposed models with a short existing/proposed models with a short operation under very low luminosity operation under very low luminosity condition. condition.
BackupBackup
Knapp, Shower curveKnapp, Shower curve
大気深さ
シャ
ワー
粒子
数
CalorimeterCalorimeter
n, gamma
n, gamma
44 radiation lengths, 1.7 hadron interaction lengths16 sampling scintillators4 position layers (2 for EM, 2 for hadron)
100-7000GeV gamma に対して <5% の分解能
ManipulatorManipulator
DC motor による駆動光学エンコーダ(放射線に弱い ! )による位置測定リニアポテンシオメータ(可変抵抗)値による位置測定
名大理学部装置開発室と共同開発
全て 200m 先の control room から制御が必要
Energy Energy resolutionresolution(gamma-(gamma-
rays)rays)
1TeV
5%
↑ MC simulation <7TeV
← SPS beam test <200GeV
Position resolutionPosition resolution