Recent results from the LHCf experiment Gaku Mitsuka (Nagoya University) on behalf of the LHCf Collaboration ISMD2012 16-21 September 2012, Jan Kochanowski University, Kielce 1
Outline Keywords: • (Ultra high energy) Cosmic rays • LHC • Forward particle productions • Introduction and Physics motivation • Analysis results - Photon analyses at √ s=900GeV and 7TeV - π 0 analysis at √ s=7TeV • Conclusions and Future prospects 2
K.Fukatsu, Y.Itow, K.Kawade, T.Mase, K.Masuda, Y.Matsubara, G.Mitsuka, K.Noda,T.Sako, K.Suzuki, K.Taki Solar-Terrestrial Environment Laboratory, Nagoya University Y.Muraki(Spokes person) K.Kasahara, M.Nakai, Y.Shimizu, S.Torii K.Yoshida Konan University Waseda University Shibaura Institute of Technology T.Tamura Kanagawa University Totally ~30 collaborators O.Adriani, L.Bonechi, M.Bongi, R.D’Alessandro, M.Grandi, H.Menjo, P .Papini, S.Ricciarini, G.Castellini, A. Viciani INFN, Univ. di Firenze A.Tricomi INFN, Univ. di Catania A-L.Perrot W.C.Turner CERN LBNL, Berkeley M.Haguenauer J.Velasco, A.Faus Ecole Polytechnique IFIC, Centro Mixto CSIC-UVEG 3
Energy spectra of high energy cosmic rays 4 10 -1 Standard (i.e. widely believed) model sr GeV sec) LEAP - satellite Proton - satellite 2 10 2 (1 particle/m -sec) Yakustk - ground array ] 1.4 Tibet&QGSJET Haverah Park - ground array 29 eV 10 KASCADE&QGSJET -1 Akeno - ground array 10 − 1 AGASA, E 0.80 × sr HiRes I/II 2 AGASA - ground array Flux (m − 1 Auger SD&FD, E × 1.15 Fly's Eye - air fluorescence yr 28 galactic (E =Z × 4.5 PeV) 10 − 2 c -4 HiRes1 mono - air fluorescence 10 proton J(E) [km helium HiRes2 mono - air fluorescence CNO 10 Z 24 ≤ ≤ HiRes Stereo - air fluorescence Z 25 ≥ -7 10 Auger - hybrid 27 10 2.4 Scaled flux E Knee -10 10 2 (1 particle/m -year) 26 10 14TeV -13 10 0.9TeV 25 10 -16 15 16 18 19 20 17 10 10 10 10 10 10 10 Energy [eV/particle] Extragalactic source (M. Unger ECRS 2008) -19 10 7TeV Ankle -22 10 2 (1 particle/km -year) Direct Indirect Energy, Composition, & direction -25 10 → Source of cosmic ray 2 (1 particle/km -century) -28 10 → Structure of the universe (goal) 9 10 13 15 16 18 19 20 11 12 14 17 10 10 10 10 10 10 10 10 10 10 10 10 Energy (eV) 4
Indirect measurement of cosmic rays • It is not possible to directly* measure cosmic rays above 10 14 eV, but possible γ p Fe indirectly using the cascade shower of daughter particles, i.e. Extensive Air- Shower(EAS). Altitude [km] • Composition and energy of cosmic rays a fg ect the generation of EAS. X max • Then understanding of high-energy cosmic ray owes to the indirect technique: comparison between the MC simulation of EAS and observation. • Largest systematic uncertainty of indirect measurement is caused by the finite Radius [km] understanding of the hadronic interaction of cosmic ray in atmosphere. * direct measurement of cosmic ray <10 14 eV is done by balloon, satellite, and ISS. 5
Hadronic interactions for CR physics CERN-LHCC-2006-004, 2008 JINST 3 S08006. Many models exist for CR physics • QGSJET (S. Ostapchenko) • EPOS (K. Werner and T. Pierog) • etc... which address on (semi-hard) soft-QCD. What should be measured by LHCf ?? 1. Energy spectra of γ , π 0 and n → Shower shape and µ at ground. 2. p T spectra → Shower lateral distribution at ground. 3. E CMS (in)dependence of the spectra → Predictive power in UHE region. 4. Nuclear e fg ects → Cosmic ray interaction is NOT p-p. 6
The LHCf detectors • p-p collision at √ s=14TeV corresponds to Arm1 E lab =10 17 eV (~ extra-galactic source). • Detectors are located at the best position to measure the large energy flow that strongly contributes the air-shower development. 140m • √ s=900GeV and 7TeV in 2009-2010 pA collisions in 2013. [TeV] Arm2 2 p-p@14TeV η dE/d 1.5 10(W)cm x 10cm(H) x 30cm(D) Sampling calorimeter, 44X 0 , 1.6 λ 1 Silicon strip detector 0.5 Arm2 ATLAS/CMS LHCf/ZDC RPs CASTOR 0 -15 -10 -5 0 5 10 15 1ch~160 µ m η 7
Photon event analyses Large tower π 0 , η , etc. γ Small tower ( η >~10) IP Large tower (8.8< η <9.5) π 0 , η , etc. γ Small tower IP 8
Photon analysis at √ s=900GeV PLB 715 (2012) 293-303. Combined data (Arm1 and Arm2) vs MC simulations • None of interaction models perfectly reproduce the LHCf data. • EPOS and SIBYLL(x~2) show a reasonable agreement with the LHCf data. • DPMJET, QGSJET and PYTHIA are in good agreement E γ <200GeV, but harder above 200GeV → E CMS dependent or independent ? 9
Photon analysis at √ s=7TeV PLB 703 (2011) 128–134. Combined data (Arm1 and Arm2) vs MC simulations -3 -3 10 10 /GeV /GeV ine ine -4 -4 LHCf s =7TeV LHCf s =7TeV 10 10 Events/N Events/N Gamma-ray like Gamma-ray like -5 -5 10 10 ° ° > 10.94, = 360 8.81 < < 8.99, = 20 η Δ φ η Δ φ -6 -6 10 10 -7 -7 10 10 ∫ ∫ -8 -1 -8 -1 Data 2010, Ldt=0.68+0.53nb Data 2010, Ldt=0.68+0.53nb 10 10 Data 2010, Stat. + Syst. error Data 2010, Stat. + Syst. error DPMJET 3.04 DPMJET 3.04 -9 -9 10 10 QGSJET II-03 QGSJET II-03 SIBYLL 2.1 SIBYLL 2.1 -10 EPOS 1.99 -10 EPOS 1.99 10 10 PYTHIA 8.145 PYTHIA 8.145 MC/Data MC/Data 2.5 2.5 2 2 1.5 1.5 1 1 0.5 0.5 0 0 500 1000 1500 2000 2500 3000 3500 500 1000 1500 2000 2500 3000 3500 Energy[GeV] Energy[GeV] • Again, none of interaction models perfectly reproduce the LHCf data. • EPOS has the smallest η -dependence relative to the LHCf data. • QGSJET and SIBYLL show the somewhat large dependent on η . • Tendencies at 900GeV are mostly same as 7TeV except for QGSJET and SIBYLL. 10
π 0 event analysis γ Large tower π 0 γ (8.9<y<11.0) Small tower IP 500 1 Events / (1 MeV) Events / (0.02) [GeV/c] LHCf-Arm1 True EPOS s =7TeV ∫ -1 LHCf-Arm1 3 0.9 -2 LHCf-Arm1 s =7TeV, Ldt=2.53nb 10 10 Unfolded(by π 0 +EPOS) 9.0 < y < 11.0 9.0 < y < 9.2 400 Unfolded(by π 0 +PYTHIA) 0.8 True spectra T E=3TeV p Measured spectra 0.7 LHCf-Arm1 Unfolded spectra(by UE-EPOS) √ s=7TeV 300 Unfolded spectra(by UE-PYTHIA) 2 -3 10 0.6 10 9.0<y<11.0 E=2TeV 0.5 200 0.4 0.3 -4 10 10 E=1TeV 100 Measured EPOS 0.2 0.1 0 80 100 120 140 160 180 0 -5 1 10 0 0.1 0.2 0.3 0.4 0.5 0.6 9 9.5 10 10.5 11 Reconstructed m [MeV] P [GeV] Rapidity γ γ T 11
π 0 analysis at √ s=7TeV Submitted to PRD (arXiv:1205.4578). MC simulations vs Combined spectra (Arm1 and Arm2 data) ] ] ] -2 -2 -2 [GeV [GeV [GeV 0 0 0 LHCf s =7TeV LHCf s =7TeV LHCf s =7TeV π π π 1 1 1 8.9 < y < 9.0 9.0 < y < 9.2 9.2 < y < 9.4 3 3 3 /dp /dp /dp ∫ ∫ ∫ -1 -1 -1 Ldt=2.53+1.90nb Ldt=2.53+1.90nb Ldt=2.53+1.90nb σ σ σ -1 -1 -1 10 10 10 3 3 3 Ed Ed Ed inel inel inel σ σ σ 1/ 1/ 1/ Data 2010 -2 -2 -2 10 10 10 DPMJET 3.04 QGSJET II-03 -3 -3 -3 SIBYLL 2.1 10 10 10 EPOS 1.99 PYTHIA 8.145 -4 -4 -4 10 10 10 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.1 0.2 0.3 0.4 0.5 0.6 p [GeV] p [GeV] p [GeV] T T T ] ] ] -2 -2 -2 [GeV [GeV [GeV 0 0 0 LHCf s =7TeV LHCf s =7TeV LHCf s =7TeV π π π 1 1 1 9.4 < y < 9.6 9.6 < y < 10.0 10.0 < y < 11.0 3 3 3 /dp /dp /dp ∫ -1 ∫ -1 ∫ -1 Ldt=2.53+1.90nb Ldt=2.53+1.90nb Ldt=2.53+1.90nb σ σ σ -1 -1 -1 10 10 10 3 3 3 Ed Ed Ed inel inel inel σ σ σ 1/ 1/ 1/ -2 -2 -2 10 10 10 -3 -3 -3 10 10 10 -4 -4 -4 10 10 10 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.1 0.2 0.3 0.4 0.5 0.6 p [GeV] p [GeV] p [GeV] T T T • LHCf data are mostly bracketed among hadronic interaction models. • DPMJET, SIBYLL(x2) and PYTHIA are apparently harder, while QGSJET2 is softer. 12
π 0 analysis at √ s=7TeV Submitted to PRD (arXiv:1205.4578). MC simulations / Combined spectra (Arm1 and Arm2 data) 5 5 5 MC/Data MC/Data MC/Data 0 0 0 LHCf s =7TeV π LHCf s =7TeV π LHCf s =7TeV π 4.5 4.5 4.5 DPMJET 3.04 8.9 < y < 9.0 9.0 < y < 9.2 9.2 < y < 9.4 4 4 4 QGSJET II-03 SIBYLL 2.1 3.5 ∫ -1 3.5 ∫ -1 3.5 ∫ -1 Ldt=2.53+1.90nb Ldt=2.53+1.90nb Ldt=2.53+1.90nb EPOS 1.99 3 3 3 PYTHIA 8.145 2.5 2.5 2.5 2 2 2 1.5 1.5 1.5 1 1 1 0.5 0.5 0.5 0 0 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.1 0.2 0.3 0.4 0.5 0.6 p [GeV] p [GeV] p [GeV] T T T 5 5 5 MC/Data MC/Data MC/Data 0 0 0 LHCf s =7TeV LHCf s =7TeV LHCf s =7TeV π π π 4.5 4.5 4.5 9.4 < y < 9.6 9.6 < y < 10.0 10.0 < y < 11.0 4 4 4 3.5 3.5 3.5 ∫ -1 ∫ -1 ∫ -1 Ldt=2.53+1.90nb Ldt=2.53+1.90nb Ldt=2.53+1.90nb 3 3 3 2.5 2.5 2.5 2 2 2 1.5 1.5 1.5 1 1 1 0.5 0.5 0.5 0 0 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.1 0.2 0.3 0.4 0.5 0.6 p [GeV] p [GeV] p [GeV] T T T • EPOS agrees well with the data among all models here. • QGSJET allows only one quark exchange in collision → leading is always baryon. 13
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