LHCf and High Energy Cosmic Rays Yoshitaka Itow STE Lab / Kobayashi-Maskawa Inst. Nagoya University and on behalf of the LHCf collaboration “HCPS 2012” Nov 12-16, 2012, Kyoto

Connection to Ultra High Energy Cosmic Rays Thanks for exciting HCP2012, various exciting results in Higgs, BSM, rere dacays, QGP, etc.. And now, something completely different point of view... Connection to Ultra High Energy Cosmic Rays

Hadron interactions at ultra high energy Accelerator n Cosmic rays 1020eV 1017eV Hadron interaction data Hint for interactions at ultra-ultra high energy ECM ~ ( 2 × Elab × Mp ) 1/2 √s=14 TeV n 1017eV cosmic rays √s=447TeV n 1020eV cosmic rays

1017 eV :Crossroad of accelerators and UHECRs AUGER TA HEAT Air shower experiments AUGER, TA TALE GZK Ankle Knee 2nd Knee? 14TeV Colliders 0.5 0.9 2.2 7 Cosmic rays 1014 1017 1020 eV LHC, Tevatron, SppS and RHIC can verify interactions at 1014 ~ 1017 eV Low E extension (TALE, HEAT) plan can verify 1017eV shower

Air shower observation Air Florescence telescope (FD) EM component (>90% of collision energy) EM component Total calorimeter Shower max altitude Had component surface detectors Surface Detectors (SD) # of particles at given altitude (EM or Muon component)

GZK cut-off confirmed ? But… UHECR2012 Need identify UHECR is “proton” Too many m @ Auger, if proton TA prefers proton Auger prefers Fe ICRC2011 ICRC2011

① Inelastic cross section If large s rapid development If small s deep penetrating ④ 2ndary interactions nucleon, p ② Forward energy spectrum If softer shallow development If harder deep penetrating ③ Inelasticity k= 1-plead/pbeam If large k (p0s carry more energy) rapid development If small k ( baryons carry more energy) deep penetrating (relevant to Nm )

Feedback from LHC to UHECRs Astropart.Phys. 35 (2011) 98-113 　sinel Central multiplicity EPL, 96 (2011) 21002 CMS PAS FWD-11-003 Forward energy flow Forward energy flow 3 3.5 4 4.5 5 h CERN-PH-EP/2011-086

Very forward : Majority of energy flow (√s=14TeV) Multiplicity Energy Flux All particles neutral 8.4 < h <　∞ Most of the energy flows into very forward ( Particles of XF > 0.1 contribute 50% of shower particles )

very forward ~ very low pT N 1 String　fragment pT (GeV/c) 2000 Energy (GeV) remnant NxE 1 pT (GeV/c) T.Pierog 2000 Energy (GeV)

The LHCf collaboration T.Iso, Y.Itow, K.Kawade, Y.Makino, K.Masuda, Y.Matsubara, E.Matsubayashi, G.Mitsuka, Y.Muraki, T.Sako Solar-Terrestrial Environment Laboratory, Nagoya Univ. H.Menjo Kobayashi-Maskawa Institute, Nagoya Univ. K.Yoshida Shibaura Institute of Technology K.Kasahara, T.Suzuki, S.Torii Waseda Univ. T.Tamura Kanagawa 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 INFN, Univ. di Firenze, Italy K.Noda, A.Tricomi INFN, Univ. di Catania, Italy A-L.Perrot CERN, Switzerland ~30 physicists from 5 countries

LHCf site ATLAS 96mm LHCf/ZDC TAN D1 magnet IP 140m Protons Charged particles (+) Neutral particles Beam pipe Protons Charged particles (-) 96mm IP ATLAS 140m LHCf/ZDC 140m TAN absorber

The LHCf detectors IP1 g n p0 Arm2 Arm1 44X0, 1.6 lint 140m calorimeter calorimeter IP1 g Arm2 n Arm1 p0 Front Counter Front Counter Arm2 Arm1 44X0, 1.6 lint 16 tungsten + pl.scinti. layers 25mmx25mm+32mmx32mm 4 Silicon strip tracking layers 16 tungsten + pl.scinti. layers 20mmx20mm+40mmx40mm 4 SciFi tracking layers

Calorimeter performance Gamma-rays (E>100GeV, dE/E<5%) Neutral Hadrons (E>a few 100 GeV, dE/E~30%) Neutral Pions (E>700GeV, dE/E<3%) Shower incident position (170mm / 40mm for Arm1/Arm2) p0 g-like Had-like

Brief history of LHCf May 2004 LOI Feb 2006 TDR Jul 2006 construction May 2004 LOI Feb 2006 TDR June 2006 LHCC approved Jan 2008 Installation Aug 2007 SPS beam test Sep 2008 1st LHC beam Mar 2010 1st 7TeV run Dec 2009 1st 900GeV run (2nd 900GeV in May2010) Jul 2010 Detector removal

LHCf single g spectra at 7TeV 0.68 (0.53)nb-1 on 15May2010 DPMJET 3.04 QGSJETII-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145 Gray hatch : Sys+stat errors Magenta hatch: Stat errors of MC h>10.94 8.81<h<8.99 8.81<h<8.99 h>10.94 Arm1 8.81<h<8.99 h>10.94 PLB 703 (2011) 128-134 Arm2 None of the models agree with data Data within the range of the model spread

LHCf single g spectra at 900 GeV PLB 715 (2012) 298-303 May2010 900GeV data ( 0.3nb-1 , 21% uncertainty not shown ) DPMJET 3.04 QGSJETII-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145 h>10.15 8.77 <h<9.46 8.77 <h<9.46 h>10.15 6 6 MC/Data 5 8.77 <h<9.46 5 4 4 3 3 2 2 1 1 h>10.15 50 E(GeV) 450 50 E(GeV) 450

Comparison of Data/MC ratio at two energies DPMJET 3.04 QGSJETII-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145 High h low h MC/Data MC/Data 2 2 7TeV 1 1 MC/Data MC/Data 900GeV 2 2 1 1

LHCf 7TeV p0 analysis Type-I Type-II Type-I sM=3.7% Type-II 1 1 Type-II PTp0(GeV/c) Ep0(GeV) 3500 Ep0(GeV) 3500

DPMJET 3.04 QGSJETII-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145 LHCf p0 PT spectra at 7TeV PRD 86 (2012) 092001 DPMJET 3.04 QGSJETII-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145 PT[GeV] 0.6 PT[GeV] 0.6 PT[GeV] 0.6 PT[GeV] 0.6 PT[GeV] 0.6 PT[GeV] 0.6

LHCf p0 PT spectra at 7TeV (data/MC) DPMJET 3.04 QGSJETII-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145 EPOS gives the best agreement both for shape and yield. MC/Data PT[GeV] 0.6 PT[GeV] 0.6 PT[GeV] 0.6 MC/Data PT[GeV] 0.6 PT[GeV] 0.6 PT[GeV] 0.6

Feed back to UHECR composition Retune done for cosmic ray MC (EPOS, QGSJET II) with all the LHC input. (cross section, forward energy flow, LHCf, etc.) Uncertainty reduced from 50 gcm2 to 20gcm2 ( p-Fe difference is 100gcm2 ) Detal reanlaysis of UHECR is also needed for conclusion. T.Pierog, S.Ostapchenko, ISVHECRI2012 Before LHC After LHC

LHCf future plan 2010 2011 2012 2013 2014 2015 0.9, 7 TeV 8TeV 14TeV LHC LS1 Detector upgrade Detector upgrade Reinstall Reinstall LHCf p-Pb LHCf II LHCf I RHICf? Analysis ongoing for 2010 data Neutron energy spectra g inelasticity. Reinstall Arm2 for p-Pb in early 2013 Very important information for nuclear effect. Under discussion of common triggers for combined analysis w/ ATLAS detector. Reinstall Arm1+2 for 14TeV in 2014 Now upgrading detectors w/ rad-hard GSO. A new measurement at RHIC 0 degree Under discussions for 500GeV p+p and d + light-A. Far future (>2020?) p-N and N-N collisions at LHC ?

Expct’d E spectra (p-remnant side ) Pb p Small tower Large tower  n

Summary UHECR needs accelerator data to solve the current enigma, and may also hint QCD at beyond-LHC energy. 1017-1014eV is an unique overlap region for colliders and UHECRs Various LHC data already implemented for cosmic rays interaction models. LHCf provides dedicated measurements of neutral particles at 0 deg to cover most of collision energy flow. E spectra for single gamma at 7TeV and at 900GeV. Agreement is “so-so”, but none of models really agree. PT spectra for 7TeV p0. EPOS gives nice agreement. Future 2004 LHC p-Pb run to study nuclear effect at 0 degree. Revisit “14TeV” at ~2014 with a rad-hard detector. Possible future RHIC run is under discussion. Possible LHC light ion runs is under discussion.

Backup

LHCf calorimeters Arm#2 Detector Arm#1 Detector 90mm 290mm

Setup in IP1-TAN (side view) BRAN-IC BRAN-Sci ZDC type2 LHCf Calorimeter LHCf Front Counter ZDC type1 Beam pipe TAN Neutral particles Side view IP1 Distance from center Beam pipe

Event sample (p0 g 2g ) Total Energy deposit Energy Shape PID X-view Longitudinal development measured by scintillator layers 25mm Tower 32mm Tower Total Energy deposit Energy Shape PID 600GeV 　　photon 420GeV 　　photon Lateral distribution measured by silicon detectors X-view Hit position, Multi-hit search. Y-view π0 mass reconstruction from two photon. Systematic studies

Forward production spectra vs Shower curve XF = E/Etot Half of shower particles comes from large XF g Measurement at very forward region is needed

Parent p0 pseudorapidity producing ground muons

The single photon energy spectra at 0 degree at 7TeV (O.Adriani et al., PLB703 (2011) 128-134 DATA 15 May 2010 17:45-21:23, at Low Luminosity 6x1028cm-2s-1, no beam crossing angle 0.68 nb-1 for Arm1, 0.53nb-1 for Arm2 MC DPMJET3.0４, QGSJETII03, SYBILL2.1, EPOS1.99 PYTHIA 8.145 with the default parameters. 107 inelastic p-p collisions by each model. Analysis Two pseudo-rapidity, η>10.94 and 8.81<η<8.99. No correction for geometrical acceptance. Luminosity by FrontCounter (VdM scan) Normalized by number of inelastic collisions with assumption as s inela = 71.5mb. (c.f. 73.5±0.6. mb by TOTEM ) Arm1 Arm2 +1.8 -1.3

New 900 GeV single g analysis 0.3nb-1 data (44k Arm1 and 63k Arm2 events ) taken at 2,3 and 27 May, 2010 Low luminosity (L~1028 typical,1 or 4 xing), negligible pile up ( 0.05 int./xing ). Relatively less h-dependence in the acceptance. Negligible multi-incidents at a calorimeter (~ 0.1 g (>50GeV) /int. ) Higher gain operation for PMTs. Energy scale calibration by SPS beam, checked with p0 in 7TeV data. g-like hadron-like PID (L90) Arm1 small 50-100GeV Mp0 in 7TeV w/ normal&high gain

XF spectra for single g: 900GeV/ 7TeV comparison (sys error not included) Arm1-Data Preliminary Arm1-EPOS Preliminary XF XF Comparing XF for common PT region at two collision energies. Less root-s dependence of PT for XF ?

LHCf g / p0 measurement η ∞ p0 @ 7TeV p0 g gg y=8.9 PT [GeV] y=10.0 1.0 h=8.40 h=8.77 h=7.60 h=6.91 h=5.99 p0 @ 7TeV PT [GeV] Energy [GeV] p0 g gg η ∞ 8.7 θ [μrad] 310 Viewed from IP1 (red:Arm1, blue:Arm2) Projected edge of beam pipe

LHCf type-I p0 analysis Low lumi (L~5e28) on 15-16May, 2.53(1.91) nb-1 at Arm1 (Arm2). About 22K (39K) p0 for Arm1(Arm2) w/ 5%BG. For Eg>100GeV, PID (g selection), shower leakage correction, energy rescaling (-8.1% and -3.8% for Arm1&2). (E, PT) spectra in +-3s p0 mass cut w/ side band subtracted. Unfolding spectra by toy p0 MC to correct acceptance and resolution 1 PTp0(GeV/c) 1/Nint Ed3N/dp3 y=8.9 y=10.0 10-4 Mp0(MeV) 0.6 　Acceptance of p0 Rapidity PTp0(GeV/c)

Average PT of p0 Comparison w/ UA7@630GeV Extend to higher h regions 1. Thermodynamics (Hagedron, Riv. Nuovo Cim. 6:10, 1 (1983)) Comparison w/ UA7@630GeV Extend to higher h regions Less energy dependence of <PT>?

Next target: Inelasticity~ 0 degree neutrons Important for Xmax and also Nm Measurement of inelasticity at LHC energy Neutral hadrons at 14 TeV (LHCf acceptance, 30% resolution) Neutral hadrons at 14 TeV (LHCf acceptance, no resolution)

Nuclear effects for very forward region Air showers take place via p-N or Fe-N collisions ! Nuclear shadowing, final state interaction, gluon saturations Nuclear modification factor at 0 degree may be large. Phys. Rev. Lett. 97 (2006) 152302 p-p QGSJET II-04 p-N All s p-Pb 8.81<<8.99 >10.94 Courtesy of S. Ostapchenko

LHCf p – Pb runs at √sNN=4.4TeV (Jan2013) IP8 IP2 IP1 Arm2 2013 Jan / a month of p-Pb opportunity. 3.5TeV p +1.38TeV/n Pb (√sNN=4.4TeV) Expected luminosity: 3×1028cm-2s-1, sAA=2b Install only Arm2 at one side (Si good for multiplicity) Trig. exchange w/ ATLAS g centrality tagging 　Requested statistics : Ncoll = 108 ( Lint = 50 mb-1 ) 　2106 single γ 　35000 0 　Assuming L = 1026 cm-2s-1 (1% of expected lumi) t = 140 h (6 days) ! Arm2 Si Elec. Preamp

“RHICf” : h acceptance for 100GeV/n d-N MC h>5.8 is covered d N All particles No acceptance forπ0 at 900GeV Neutrals Acceptance for p0 Energy flow

Future p-N and Fe-N in LHC ? LHC 7TeV/Z p-N and N-N collisions realize the laboratory energy of 5.2x1016eV and 3.6x1017eV, respectively (N: Nitrogen) Suggestions from the CERN ion source experts: LHC can in principle circulate any kind of ions, but switching ion source takes considerable time and manpower Oxygen can be a good candidate because it is used as a ‘support gas’ for Pb ion production. This reduces the switching time and impact to the main physics program at LHC. According to the current LHC schedule, the realization is not earlier than 2020. New ion source for medical facility in discussion will enable even Fe-N collisions in future