The LHCf (LHC forward) experiment ~ a collider experiment dedicated for ultra-high-energy cosmic-ray physics ~ Koji Noda for the LHCf Collaboration INFN (Section of Catania), Italy 6th European Summer School on Experimental Nuclear Astrophysics, Acireale, Italy, 18-27 Sep 2011 1
Very-high-energy cosmic ray specrum Cosmic ray spectrum SPS Tevatron LHC M Nagano New Journal of Physics 11 (2009) 065012 AUGER SPS Tevatron LHC (UA7) 10^17eV CR (fixed target) <=> cm energy at LHC (7+7TeV) >10^15eV: detected with air-showers , but many unknowns
Air-sho shower er 1. Inelastic cross section develop elopment ment If large rapid development If small deep penetrating 4. 2ndary interactions 2. Forward energy spectrum If softer rapid development If harder deep penetrating 3. Inelasticity k (1-E leading )/E 0 If large k rapid development If small k deep penetrating 3
Ha Hadr dron on in interaction action mo mode del - ma majo jor r sou ource rce of of unc ncertainty tainty - deep penetrating rapid development LHC data is expected to reduce this uncertainty 4
Wha hat t sh shou ould d be be measu sured? red? sqrt(s)=14TeV multiplicity and energy flux at LHC 14TeV collisions pseudo-rapidity; = -ln(tan( /2)) Multiplicity Energy Flux E lab =10 17 eV All particles neutral Most of the energy flows into very forward 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 INFN, Univ. di Catania, Italy J.Velasco, A.Faus IFIC, Centro Mixto CSIC-UVEG, Spain A-L.Perrot CERN, Switzerland 6
Det Detec ector or Loc ocati tion on 140m 7
LHCf LH Cf Det Detec ector ors Imaging sampling shower calorimeters Two independent calorimeters in each detector (Tungsten 44r.l., 1.6 , sampling with plastic scintillators) 4 position sensitive layers distributed in the calorimeters Arm#1 Detector 20mmx20mm+40mmx40mm 4 XY SciFi+MAPMT Arm#2 Detector 25mmx25mm+32mmx32mm 4 XY Silicon strip detectors 8
De Detec ector or ph photos os Arm#2 Detector Arm#1 Detector
Ev Event ent ca catego gory y of of LH LHCf Cf Single hadron event Single photon event Pi-zero event (photon pair) 10
Ex Expe pect cted ed Results ults at 14 TeV Col ollision sions (MC assuming 0.1nb -1 statistics) Single photon at different Single photon Detector response not considered Single neutron 0 11
Summar mmary y of Op Opera rations tions in 200 009 9 and 2010 With Stable Beam at 900 GeV Total of 42 hours for physics About ut 100 k showers events in Arm1+Arm2 With Stable Beam at 7 TeV 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 400 M shower events in Arm1+Arm2 1 M 0 events in Arm1+Arm2 0 stat. Arm1 Status Com omple leted ed program am for 900 GeV and 7 TeV Remo moved ed det etect ector ors s from m tun unnel nel in Jul uly 2010 Post-calib calibrat ation on beam m test in Octob ober er 2010 s for 14TeV in 2014 Upgrade Up ade on-going going to more re rad-ha hard d det etect ector ors 12
EM sho EM hower er and nd 0 id identif ntification ication Event sample in Arm2 • A Pi0 candidate event • 599GeV & 419GeV photons in 25mm Longitudinal development and 32mm tower, respectively Large Small • M = x sqrt(E 1 xE 2 ) Cal. Cal. Lateral development Silicon X Silicon Y Comparison with models, coming soon Invariant mass of photon pairs 13
Ph Photon on spe pect ctra ra at t 7TeV eV co coll llisions isions (Published in PLB, ArXiv:1104:.5294v2 [hep-ex]) The simplest photon spectra by Arm1 & Arm2 at common rapidity N ine = ine x int(Ldt) ( ine = 71.5mb assumed; consistent with recent ATLAS result) e/h shower separation based on the longitudinal shower development => Combined & compared with MC models 14
Comparison between Models Magenta hatch: MC Statistical errors Gray hatch : Systematic Errors DPMJET 3.04 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145 QGSJET II-03 • None of the models nicely describe the LHCf data in the whole energy range (100 GeV – 3.5 TeV). • Very big discrepancy in the high energy region (>2 TeV) • Significant improvement of the models is possible with model developers 15
Upgr Upgrade ade for or 14T 4TeV eV for rad-hardness higher luminosity is expected in Kawade+ (2011) the 14TeV runs for improvement of energy reconstruction Silicon layer positions in Arm2 detector X,Y X,Y X,Y X,Y X,Y X,Y X X Y Y Energy reconstruction with the Si layers is also useful! 16
Ana naly lysis is of of th the e Si Si la layer ers (my ongoing work) Energy reconstruction with the Si data a multi-hit events in a calorimeter complementary to that with the scintillators for separation of multi-hits in 1 tower It requires A B calibration (ADC count -> energy deposit -> incident energy) correction for the saturation effects (only for high-E events) A (gain calibration) B (incident E reconstruction with MC) Test beam at SPS in 2010 Energy of incident : 50, 100, 200, 500GeV, 1, 2, 3TeV • 100, 150, 175, 200GeV e - • comparison with MC • averaged over energies => Gain: 42.8 ADC/MeV, +0.5%-1.0% (sys.) dE-E errors: sys. from diff. methods relation dE on Si => E with Refinement of the ~3% precision methods is ongoing 17
Summ Su mmar ary & P & Pros ospe pects ts LHCf is a cosmic-ray dedicated experiment in LHC DAQ in LHC sqrt(s) = 7 TeV pp collisions completed Analyses Photon spectra at sqrt(s) = 7TeV (published in PLB) Completed Photon spectra at sqrt(s) = 0.9 TeV In progress 0 spectra In consideration Impact on EAS Energy reconstruction improvement P T spectra, Hadron spectra, test for LPM effect Correlation with central production (joint analysis with ATLAS) Measurements LHC sqrt(s) = 14 TeV pp (scheduled after 2014; rad-hard upgrade on going) in study: LHC p-Pb (2012?), possibility in the other colliders N-p, N-N, N-Fe (N; Nitrogen) in future? Still many dishes to enjoy!! 18
Backup 19
Very forward – connection to low-x physics (slides by Y. Itow) Low-x high-x Very forward Very forward region : collision of a low-x parton with a large-x parton Small-x gluon become dominating in higher energy collision by self interaction. But they may be saturated (Color Glass Condensation) Naively CGC-like suppression may occur in very forward at high energy g However situation is more complex (not simple hard parton collisions, but including soft + semi-hard ) semi- soft hard hard
Physics of MCs ( K. Werner, EDS09, CERN)
Nonlinear effects in MCs Non-linear effects are implemented in a phenomenological manner all slides are by K. Werner, EDS09, CERN
air-shower development: Xmax p 10 19 19 eV eV
FrontCounter 2 fixed Front Counters installed in front of Arm1 and Arm2 They will not move with Arm1 and Arm2 segmented in 2 x- and 2 y-slices Very useful to check the beam quality Alessia Tricomi University and INFN Catania EPS 09, Krakow 16-22 July 2009
Acceptance eptance π 0 Photon at √s =14TeV pp collision 25
2010 operation at √s=7TeV High luminosity (L=3~20e29cm 2 s -1 ) Low luminosity (L=2~10e28cm 2 s -1 ) (1e11ppb, b*=3.5m,Nb=1~8) (1~2.5e10ppb, =2m,N b =1~4) 100 rad crossing No crossing angle 900GeV # of showers 10 8 Detector removed 10 7 10 6 5/27 4/1 7/22 1000K 0 0 stat. Arm1 # of 500K 4/4 5/30 7/25 26
Parti ticle le ID EM and hadronic shower separation based on the longitudinal shower development N photon /N hadron ratio will give a good information for model Response of detectors to hadrons in study 27
Gam ame wit with h mo modi dified ied me meson on spe pect ctrum rum Play within the model uncertainty Play within the LHCf error 28
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