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The LHCf experiment Verification of UHECR interaction by LHC

The LHCf experiment Verification of UHECR interaction by LHC. Yoshitaka Itow Solar-Terrestrial Environment Laboratory, Nagoya University For the LHCf collaboration. High Energy Cosmic Ray Observations. 1 particle / m 2 s. Knee 1 particle / m 2 year. Extensive Air Shower experiments.

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The LHCf experiment Verification of UHECR interaction by LHC

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  1. The LHCf experimentVerification of UHECR interaction by LHC Yoshitaka Itow Solar-Terrestrial Environment Laboratory, Nagoya University For the LHCf collaboration

  2. High Energy Cosmic Ray Observations 1 particle / m2s Knee 1 particle / m2year Extensive Air Shower experiments Ankle 1 particle / km2year (eV) 1010 1015 1020

  3. Air Florescence telescope (FD) Surface Detectors (SD)

  4. HiRes (FD) 100km2 AGASA (SD) 760km2 3000km2 TA (SD+FD) AUGER (SD+FD)

  5. GZK or not ? AUGER ICRC07 T.Yamamoto et al ICRC07,astro-ph/0707.2638 GZK cut off ? AUGER sees transition of spectrum index, however.. • Discrepancy among existing experiments ? • Energy scale? Composition ? Arrival direction ?

  6. Arrival directions of UHECRs in AUGER Science 318 938 (2007) 27 UHECRs w/ E>5.7×1019eV have correlation to AGNs with 3.1 deg error circles. UHECR = proton ?

  7. Composition at GZK region M.Unger et al ICRC07,astro-ph/0706.1495 SIBYL2.1 : proton QGSJETII-03 : proton QGSJETII03 : Iron SIBYL2.1 : Iron p or Fe ? is important to understand origin

  8. Model dependence of air shower development J.Knapp Astropart. Phys.19 (2003) 77 • Surface detector would get uncertainty of E-scale (AGASA claims 20%) • Florescence should be OK ( a few %) for E-scale But FD fg SD problem • Composition uncertainty #of particles Model dependence AUGER alt. Atm. depth

  9. ① Inelastic cross section If large s rapid development If small s deep penetrating ② Forward energy spectrum (or Inelasticity k ) If large k rapid development If small k deep penetrating Shower development vs ① and ② (degenerated)

  10. Forward production spectra vs Shower curve Half of shower particles comes from large XFg Measurement at very forward region is needed

  11. Better understanding of UHECR air shower • Inelastic cross section • Total and elastic cross section at LHC provided by diffractive proton measurement in “Roman-pod” experiments (i.e.TOTEM) • Low energy hadron interaction models should be also refined • Forward production spectrum • Dominated by soft hadronic processes which are poorly known • Need measurement by a zero-degree calorimeter Dedicated detector at LHC covering very forward 8.0 < h <　∞ The LHCf experiment psuedorapidity η = −ln(tan( θ/ 2 )) θ p p

  12. LHCf experiment • Measurement of g and n at 0 deg at 1017eV Discriminate models (QGSJET, SIBYLL,EPOS etc.) Calibrate XF, PT, inelasticity etc. at 1017eV • Dedicated detectors located at +-140m at IP1 IP5, CMS IP1, ATLAS, LHCf IP8, LHCb IP2, ALICE LHC: 7TeV+7TeV collision g 1017eV at lab frame • First collision at 2008

  13. The LHCf Collaboration CERN D.Macina, A.L. Perrot USA LBNL Berkeley: W. Turner FRANCE Ecole Politechnique Paris: M. Haguenauer JAPAN: STE Laboratory Nagoya University: K.Fukui, Y.Itow,T.Mase, K.Masuda, Y. Matsubara,H.Menjo,T.Sako, K.Taki, H. Watanabe Shibaura Institute of Technology:K.Yoshida Kanagawa University: T.Tamura, K.Tanaka Konan University: Y.Muraki Waseda University:K.Kasahara, K.Mizuishi, Y.Shimizu, S.Torii SPAIN IFIC Valencia: A.Fauss, J.Velasco ITALY Firenze University and INFN: O.Adriani,, L.Bonechi, M.Bongi, G.Castellini, R.D’Alessandro, P.Papini Catania University and INFN: A.Tricomi

  14. The 6th approved experiment at LHC Letter Of Intent: May 2004 Technical report: September 2005 Technical Design Report: February 2006 LHCC approval: June 7th, 2006 Detector assembly,beam test: 2007 Installation in the LHC tunnel: Feb 2008

  15. Compact calorimeter 95mm 140m LHCf experimental site IP1 LHCf Detector ATLAS 140m TAN absorber

  16. Detector #1 Impact point (h) 2 towers ~24 cm long stacked vertically with 5 mm gap Lower:2 cm x 2 cm area Upper: 4 cm x 4 cm area 4 pairs of scintillating fiber layers for tracking purpose (6, 10, 30, 42 r.l.) Absorber 22 tungsten layers 7mm thick  44 X0(1.6 lI)in total (W: X0 = 3.5mm, RM = 9mm) q < 300 mrad Very compact EM shower Compact to prevent multi particle hits Double stacks to tag p0 g 2g 16 scintillator layers (3 mm thick) Trigger and energy profile measurements Energy ~4% for EM ~30% for Hadrons DE/E =

  17. Detector # 2 We use LHC style electronics and readout Placed opposite side of detector#1 2 towers 24 cm long stacked on their edges and offset from one another Lower:2.5 cm x 2.5 cm Upper: 3.2 cm x 3.2 cm 4 pairs of silicon microstrip layers (6, 12, 30, 42 r.l.) for tracking purpose (X and Y)  impact point q < 400 mrad 16 scintillator layers (3 mm thick) Trigger and energy profile measurements Absorber 22 tungsten layers 7mm thick  44 X0 (1.6 lI) in total (W: X0 = 3.5mm, RM = 9mm)

  18. Detectors already in hand and calibrated Detector #1 Detector #2

  19. Acceptance “450 mrad” fg 140 mrad xing angle “310 mrad” fg 0 mrad xing angle Beam pipe cut-view Vertical scanning is available remotely

  20. Monte Carlo g ray energy spectrum (5% Energy resolution is taken into account) 105events in 3min. ! (@1029 cm-2s-1 ) Shape analysis can discriminate SIBYLL from others (c2 =135/67dof)

  21. Energy spectrum of π0 expected from different models Dm ~ 5% QGSJETII ⇔ DPMJET3 χ2= 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 10K p0 in 20 min @ L=1029cm-2s-1

  22. Model dependence of neutron energy distribution Original n energy 30% energy resolution

  23. Typical event rate of LHCf @L=1029cm-2s-1 For L= 1029 cm-2s-1, ~ 10kHz inelastic collisions Very quick measurement ! 30% analysis efficiency Is assumed for hadrons

  24. From R. Bailey presentation at January 2007 TAN workshop

  25. LHCf proposed running scenario • 2008 : Phase-I ( During LHC commissioning ) • Run since the very beginning of LHC operations (L<1031cm-2s-1, 43 bunches) • First 7TeV collision is expected in summer? 2008 • The LHCf detector is not radiation-hard. But still 10Gy/days@L=1029/cm2s for a week operation will not be a problem. • 200? : Phase-II (Dedicated run ) • Re-install the detector at the next opportunity of low luminosity run ( Possibly with TOTEM run ) • Enlarge covered PT region, more detail study • 200? : Phase-III ( possible heavy ion run ) • Nuclear effect plays an essential role in “muons” • Future extension for p-A, A-A run with upgraded detectors? So far approved

  26. Status of experiment • Final calibration was done by SPS beam test (Sep 07) • Both detectors were installed in TAN (Feb08) • Doing In-situ calibration and detector commissioning • Appear in official LHC web page (open official LHCf web) • See www.stelab.nagoya-u.ac.jp/LHCf • Design official LHCf logo

  27. Detector installation (Jan08) Just 40 min. work

  28. Installed detector in TAN

  29. Summary • Analyses of UHECR air showers rely on production models at very forward, which should be experimentally verified at energy as high as possible. Even all current models may be wrong. • LHCf : Dedicated measurements of neutral particles at 0 deg by LHC, providing calibration of interaction models at 1017eV. • Approved parasite measurements by two small sampling calorimeters at +-140m from IP1 during LHC commissioning in 2008 • Just “one day” measurement provides good discrimination of various models in the market. • All the detectors and electronics in hand. Calibration by SPS beam has been done. Now installed in LHC. We are waiting for the LHC 1st collision !

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