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  1. LHCf Status Oscar Adriani CSN1,MIlano, 26 Marzo 2013

  2. Summary of operations in end 2012- beginning 2013 (after the Torino meeting) Arm2 has been re-installed in the TAN region in December 2012 January-February 2013: p/Pb run Arm2 will be removed from the TAN in April 2013 The Arm2 upgrade for the 13 TeV run will be done in Florence in 2013 in strict collaboration with Japanese colleagues Some more details will be given in the next slides

  3. Re-Installation issues • Arm2 has been successfully re-installed in the TAN during the technical stop foreseen at the end of the p/p run  December 18th • We have modified the LHCf support structure and cabling to significantly reduce the installation required time • Mechanical survey has been done in 2 steps: • Internal LHCf survey on ground • LHCf survey wrt to LHC: done on December 18th in the TAN area • No big problem of radiation, the installation was completely safe (Thanks to Raffaello and Sako!!!)

  4. Discussions and agreements with ATLAS (I) • ATLAS trigger can not be sent to LHCf due to timing problem • LHCf Level1 Trigger signal has been sent to ATLAS for the whole p/Pb running period • ATLAS hasproperly prescaledthe LHCf trigger signal • Prescalingfactor depend on the running conditions • LHCf has recorded in the data stream all the counters and has used all the signals necessary to off-line identify the common events • Event Counter Reset • Atlas L1ID • Bunch ID

  5. Discussions and agreements with ATLAS (II)

  6. Proton remnant side – Invariant cross section for isolated g-raysUsing only the LHCf informations

  7. What happens if know the Impact Parameter? Ideal case, assuming that we can precisely know the Impact Parameter b (in fm) on event by event basis

  8. What happens if know the Impact Parameter?

  9. What happens if know the Impact Parameter?

  10. What happens if know the Impact Parameter?

  11. What happens if know the Impact Parameter?

  12. Combination of different impact parameter bins The difference between models is enhanced by the knowledge of the impact parameter In real life b should be estimated by using the Atlas information (centrality)

  13. What happens with LHCf on Pb remnant side? Nominal vertical position (Dy=0 cm)

  14. Shifting up by y= +2.5 cm The small calorimeter tower remain in the region not screened by the narrow elliptical shape of the beam pipe at D1 magnet  We can take good data with reasonable number of hits!

  15. Pb p IP1 IP1 IP2 IP2 IP8 IP8 Arm2 Arm2 p Pb LHCf operation in p – Pb runs at √sNN= 5 TeV Proton remnant side Lead remnant side

  16. p-remnant side Pb-remnant side #Events (Millions) Beam reversal 20 Jan 27 Jan. 01 Feb. LHCf operation in p – Pb runs at √sNN= 5 TeV 200 Millions triggered events!!!!

  17. Summary of LHCf p-Pb runs • L = 0.5x1029– 1x1029cm-2s-1 • b* =0.8m, 145mrad crossing angle • Not good for LHCf…. • We didn’t succeed to get a dedicated high b* run due to the lack of time • 338p+338Pb bunches (min.DT=200ns), 296 colliding at IP1 • 10-20kHz trig rate downscaled to ~700Hz • 20-40Hz ATLAS common trig • Coincidence operation was successful!!! • Data both at p-side (20Jan-1Feb) and Pb-side (1fill, 4Feb)

  18. p IP1 IP2 IP8 Arm2 Pb Operation at Pb-remnant side MC (Pb-remnant) 3.5cm, 4.0cm A high multiplicity event (Pb-side)

  19. Proton-Proton Collision at √s = 2.76 TeV • We also profited of the ‘calibration’ run at √s = 2.76 TeV that has been done following the ATLAS and CMS requests • 4 hours operation on 14 Feb. 2013 successfully done. • These data will allow a better study of the energy Scaling by comparing different c.m. energy (0.9 TeV, 2.76 TeV, 7 TeV, 13 TeV)

  20. Data list of LHCf With ATLAS π0 γ, n Black: completedoperations Orange: Future operations

  21. Playing a game with air shower development:effect of forward meson spectra • DPMJET3 always overpredicts production • Filtering DPMJET3 mesons • according to an empirical probability function, divide mesons into two with keeping pT • Fraction of mesons escape out of LHCf acceptance • This process • Holds cross section • Holds elasticity/inelasticity • Holds energy conservation • Changes multiplicity • Does not conserve charge event-by-event pT E1 E2 E=E1+E2 xF = E/E0 xF = E/E0

  22. An example of filtering photon spectrum π0 spectrum DPMJET3+filter 2.5x1016eV proton ~30g/cm2 Apart from this ‘game’ we are in strict contacts with model developers to help them improving their codes. Few dedicated workshops have been organized to put theorists and experimentalists in contact

  23. π0 spectrum and air shower 100 g/cm2 Vertical Depth (g/cm2) AUGER, ICRC 2011 30 g/cm2

  24. Other analyses and future activities…. Joint analysis with ATLAS … data ready 14 TeV p-p in 2015 … detector upgrade on going Neutron spectra in 7TeV p-p … analysis on going Light nuclei at LHC, RHIC??? … possibility in discussion

  25. LHCf preparation for the 14 TeV p-p run • Calorimeter radiation hardening by replacing plastic scintillator with GSO • Production and laboratory tests of the new scintillators in Japan is finished for Arm1 and in progress for Arm2 • Beam test at Ion facility (HIMAC) for Arm1 has been done in June 2012 • Arm1 has been re-assembled in Florence starting from end of June 2012 • Same procedure will be followed in 2013 for the Arm2 detector • Upgrade of the silicon positioning measurement system • Rearranging Silicon layers for independent precise energy measurement • Increase the dynamic range to reduce saturation effects • Test Beam at LNS for the absolute energy calibration of the silicon system is being requested

  26. Why neutron measurement is important for CR physics • Auger hybrid analysis • event-by-event MC selection to fit FD data (topplot) • comparison with SD data vs MC (bottom plot) • Clear muon excess in data even for Fe primary MC • The number of muons increases with the increase of the number of baryons! • => importance of direct baryon measurement

  27. Neutron Spectra at 7 TeVpp(models) Model predictions Model predictions smeared taking into account the LHCf energy resolution

  28. Life is not easy….. 1 TeV neutrons simulated with 2 different hadronic interaction models used in the detector simulation

  29. Otherpossibile future runs? • Possibility to use LIGHT IONS in LHC from 2016/2017? • Light Ion source setup is ongoing because of SPS interest • RHIC run in 2015/2016 isunder discussion… • Please stand by a little bit to see how things are evolving!!!!

  30. Il calcoloper LHCf • A settembre la CSN1 ci ha ‘suggerito’ di muoversinelladirezione di utilizzare le risorse di calcolo del CNAF (nonostante le richiesteestremamentelimitate di 15 kEuro) • In questimesi, con l’aiuto di Vincenzo Vagnoni e con ilsupporto di Luca Dell’Agnello, abbiamosistemato le infrastrutturetecnichenecessarie per: • Generazione(per almeno 4 modelli di interazioneadronica) • End2End (trasporto beam-pipe) • DoubleArm (simulazione del rivelatore) • Compilatori, spazio di storage, creazionedegli account e delle code per I jobs, etc. • Il sistemaora e’ ‘pronto per partire’

  31. Necessita’ • Almeno 4x107eventi • Generazione: • 35 kB/event • 0.1 sec/event • Trasporto: • 100-500 kB/event • 100-500 sec/event • Simulazione: • 20 kB/event • 10 sec/event • CPU: • Almeno4x109 secondi estendibili a 1.3x1010 sec se ci fosse la necessità di avere 108eventi per un modello • Storage: • 20-30 TB

  32. Come staandando Siamo in contatto con CNAF per finire di risolvereiproblemitecnicirimasti La procedura e’ statafaticosa, ma alla fine siamo (quasi) arrivati…. Non mi e’ chiaro come orasianecessarioprocedere con la commissione per pagare le risorse CNAF….

  33. Conclusions • Re-installation in the tunnel and p/Pb run went very smooth • p/Pb and neutron analyses are on-going • Atlas joint analysis is ready to start • Arm2 upgrade will be completed in 2013 • Computing system at CNAF is available • Ready to take data at 14 TeV • And…. Possible Light Ions runs at RHIC/LHC are under investigation • Next week we will have the LHCf meeting in Nagoya

  34. Spares slides

  35. Miscellanea IV: LHCf computing • Lo scorso anno abbiamopresentato un piccolo modello di calcolo per far frontealleesigenze di simulazione e ricostruzione di LHCf per il run p-Pb di cui siamoresponsabili • I referee ci hannofinanziatouna parte di quellorichiestorimandando a quest’anno la seconda parte a fronte di stimepiù precise per consentirci la produzionedei plot per la LOI • Il data set per la LOI èstatoprodottointeramente in Italia e le tremacchineacquistatesono state fondamentali • Abbiamofattoiprimi test di simulazionecompleta con p-Pb • 500 KB per evento e 570 sec/evento con la simulazionecompleta • 20 KB per evento e 22 sec/evento se applichiamodeitaglicinematiciabbastanzaduri (eccessivi per quellochevorremmo fare) • Unavia di mezzo traqueste due, dell'ordinedei 100 KB e 100 sec/evento e' quellapiu' realisticasenzaperdereinformazioni di fisicarilevanti. • Noiabbiamobisogno di produrre come minimo107eventi per ciascunodeimodellistudiati(finora 5) • Poichè le stimedelloscorso anno, basatesulla sola generazioneerano ben piùottimistiche di quellocheabbiamoottenutoora, chiediamoilcompletamentodellerisorse. Per il disco cercheremo di utilizzarerisorsepresenti in sezione ma abbiamobisogno di CPU dedicate • 15 Keuro per l’acquistodelle CPU

  36. Radiation hardness of GSO Dose rate=2 kGy/hour (≈1032cm-2s-1) Irradiated sample Not irradiated ref. sample 1kGy K. Kawadeet al., JINST, 6, T09004, 2011 τ~4.2h recovery No decrease up to 1 MGy +20% increase over 1 kGy (τ=4.2h recovery) 2 kGy is expected for 350nb-1 @ 14TeV pp)

  37. Proton-remnant side – photon spectrum Small tower Big tower

  38. Proton-remnant side – neutron spectrum Small tower Big tower 35% ENERGY RESOLUTION IS CONSIDERED IN THESE PLOTS

  39. What LHCf can measure in the p+Pb run (2)Study of the Nuclear Modification Factor Nuclear Modification Factor measured at RHIC (production of p0): strong suppression for small pt at <>=4. LHCf can extend the measurement at higher energy and for >8.4 Very important for CR Physics Phys. Rev. Lett. 97 (2006) 152302

  40. Lead-remnant side – multiplicityPlease remind that EPOS does not consider Fermi motion and Nuclear Fragmentation Small tower Big tower  n

  41. π0 results: Data vs MC

  42. Submitted to PRD (arXiv:1205.4578). π0 results: Data/MC

  43. <pT> distribution Three different approaches used to derive the average transverse momentum, ⟨pT⟩ by fitting an empirical function to the pTspectra in each rapidity range (exponential distribution based on a thermodynamical approach) By fitting a gaussiandistribution by simply numerically integrating the pTspectra Results of the three methods are in agreement and are compared with UA7 data and hadronic model predictions. Two UA7 and LHCf experimental data show the same trend → no evident dependence of <pT> on ECMS. YBeam=6.5 for SPS YBeam=8.92 for7 TeV LHC

  44. Comparison wrt MC Models at 900 GeV

  45. A jump back to g analysis: Comparison btw 900GeVand 7TeV spectra Coverage of the photon spectra in the plane Feynman-X vs PT XF spectra : 900GeV data vs. 7TeV data Preliminary 900GeVvs. 7TeVwith the same PT region Data 2010 at √s=900GeV (Normalized by the number of entries in XF > 0.1)Data 2010 at √s=7TeV (η>10.94) small-η = Large tower 900 GeV Small+large tower big-η =Small tower • Normalized by the number of entries in XF > 0.1 • No systematic error is considered in both collision energies. Good agreement of XF spectrum shape between 900 GeV and 7 TeV. weak dependence of <pT> on ECMS

  46. Neutron Detection Efficiency and energy linearity Linear fit Parabolic fit % Efficiency at the offline shower trigger Flat efficiency >500GeV

  47. Energy and Position Resolution XY We are trying to improve the energy resolution by looking at the ‘electromagneticity’ of the event Neutron incident at (X,Y) = (8.5mm, 11.5mm) ~1mm position resolution Weak dependence on incident energy

  48. K0 analysis