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LHCf Status

LHCf Status. Oscar Adriani University of Florence & INFN Firenze On behalf of the LHCf Collaboration. June 13 th , 2012. Introduction and contents. LHCf status after march 2012 LHCC p 0 paper submitted to PRD Selected final results will be shown Short spot on neutron analysis

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LHCf Status

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  1. LHCf Status Oscar Adriani University of Florence & INFN Firenze On behalf of the LHCf Collaboration June 13th, 2012

  2. Introduction and contents • LHCf status after march 2012 LHCC • p0 paper submitted to PRD • Selected final results will be shown • Short spot on neutron analysis • Arm1 upgrade for 2014 run under way • Preparation for p/Pbautumn run O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  3. LHCf: location and detector layout 140 m 140 m γ 8 cm 6 cm n γ π0 Arm#2 Detector 25mmx25mm+32mmx32mm 4 X-Y Silicon strip tracking layers Arm#1 Detector 20mmx20mm+40mmx40mm 4 X-Y SciFitracking layers Detector II Tungsten Scintillator Silicon mstrips Detector I Tungsten Scintillator Scintillatingfibers INTERACTION POINT IP1 (ATLAS) Front Counter Front Counter 44X0, 1.6 lint O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  4. π0analysis: PT spectra for different rapidity bins Submitted to PRD CERN-PH-EP-2012-145

  5. π0 analysis at √s=7TeV Submitted to PRD (arXiv:1205.4578). Type-I Type-II • Small angle • large BG • Low-stat., but can cover • High-E • Large-PT • Large angle • Simple • Clean • High-stat. Type-ILHCf-Arm1 Type-IILHCf-Arm1 LHCf-Arm1Data 2010 Preliminary Type-II at large tower BG Type-II at small tower Signal O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  6. Type I π0 analysis procedure Mass, energy and transverse momentum are reconstructed from the energies and impact positions of photon pairs measured by each calorimeter 1(E1) • Analysis Procedure • Standard photon reconstruction • Event selection - one photon in each calorimeter- reconstructed invariant mass • Background subtraction by using outer region of mass peak • Unfolding for detector response. • Acceptance correction. R 140m  2(E2) I.P.1 Dedicated part for π0 analysis O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  7. Acceptance and unfolding Submitted to PRD (arXiv:1205.4578). • Remaining background spectrum is estimated using the sideband information, then the BG spectrum is subtracted from the spectrum obtained in the signal window. • Raw distributions are corrected for detector responses by an unfolding process that is based on the iterative Bayesian method.(G. D’Agostini NIM A 362 (1995) 487) • Detector response corrected spectrum is then corrected for acceptance Acceptance for π0 at LHCf-Arm1 Validity check of unfolding method True EPOSUnfolded(by π0+EPOS)Unfolded(by π0+PYTHIA) LHCf-Arm1√s=7TeV9.0<y<11.0 Measured EPOS O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  8. Arm1 vs Arm2 comparison O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  9. π0 results: Data vs MC O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  10. Submitted to PRD (arXiv:1205.4578). π0 results: Data/MC O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  11. Data/MC commented • dpmjet 3.04 & pythia 8.145 show overall agreement with LHCf data for 9.2<y<9.6 and pT <0.25 GeV/c, while the expected p0 production rates by both models exceed the LHCf data as pT becomes large • sibyll 2.1 predicts harder pion spectra than data, but the expected p0yield is generally small • qgsjet II-03 predicts p0 spectra softer than LHCf data • epos 1.99 shows the best overall agreement with the LHCfdata. • behaves softer in the low pT region, pT< 0.4GeV/c in 9.0<y<9.4 and pT <0.3GeV/c in 9.4<y<9.6 • behaves harder in the large pT region. O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  12. <pT> distribution Two different approaches used to derive the average transverse momentum, ⟨pT⟩ in different rapidity bins: by fitting an empirical function to the pTspectra in each rapidity range (thermodynamical approach) by simply numerically integrating the pTspectra Results of the two 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 YLAB= Ybeam - Y O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  13. A jump back to g analysis: Comparison btw 900GeVand 7TeV spectra Coverage of the photon spectra in the plane Feynman-X vs PT small-η = Large tower big-η =Small tower O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  14. A jump back to g analysis: Comparison btw 900GeVand 7TeV spectra Coverage of the photon spectra in the plane Feynman-X vs PT 900GeVvs. 7TeVwith the same PT region small-η = Large tower 900 GeV Small+large tower big-η =Small tower O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  15. 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 O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  16. Neutron (very preliminary…) analysis

  17. 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

  18. Neutron Detection Efficiency and energy linearity Linear fit Parabolic fit % Efficiency at the offline shower trigger Flat efficiency >500GeV O. Adriani LHCf: results on forward particle production at LHC anf future perspectives Paris, June 11, 2012

  19. 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 O. Adriani LHCf: results on forward particle production at LHC anf future perspectives Paris, June 11, 2012

  20. Status of the LHCf upgrade and re-installation issues for p/Pb 2012 run

  21. LHCf Upgrade for the 14 TeV p-p run • Calorimeter radiation hardening by replacing plastic scintillator with GSO • Scintillator plates • 3 mm  1mm thick scintillators • Acrylic  quartz light guides  construction and light yield uniformity test carried out in Japan • SciFi • 1 mm square fibers  1 mm GSO square bars • No clad-core structure (GSO bar)  Attenuation and cross talk test carried out • Acrylic light guide fiber  quartz light guide fibers  Construction and light yield test carried out • Production and laboratory tests of the new scintillators in Japan is finished • Beam test at Ion facility (HIMAC) is underway this week • Arm1 will be re-assembled in Florence starting from end of June • 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 O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  22. O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  23. Re-installation for the p/Pb run • Arm2 will be re-installed in the TAN during the technical stop foreseen at the end of the p/p run • We have modified the LHCf support structure and cabling to significantly reduce the installation required time • The procedure for reinstallation  has been carefully discussed in the LTEX meetings and is ready • Checked with RP  RP gave green light • We will continue discussion with ATLAS for trigger and data exchange, to get the maximum physics outcome for the data, following the LHCC reccomendation O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  24. Conclusions • Three physics papers have been completed: • Inclusive g at 900 GeV • Inclusive gat 7TeV • p0Ptvs y spectra • We are in strict contacts with model developers, and the feedback from our data is important and appreciated in the community • Neutron analysis is ongoing and is our next priority • Upgrade work for 14 TeV almost completed for Arm1  Beam test in August • p/Pb interesting physics case will be investigated by LHCf with Arm2 detector in Autumn O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  25. Spares slides O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  26. Fast install/uninstall Now 35 BNC connections in the tunnel To be packed in 2-3 Hartingmultipoles connectors Silicon strip FE electronics Calorimeters amplifier LHCf main detector To be assembled in a single structure Now 3 main structures installed separately O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  27. 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) O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  28. Uniformity test using C beam at HIMAC(preliminary results from quick analysis) mm mm mm No particle due to the beam pipe PMT via fiber bundle • Scan examples for a 20mmx20mm and a 40mmx40mm GSO plates • All scintillators of Arm1 were mapped by C beam • Similar uniformity to the current detector is obtained mm PMT via fiber bundle O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  29. GSO bars cross talk and attenuation No paint between bars 10% Irradiated bar (100%) -30%/35mm 0% Attenuation along the longest 40mm bar Cross talk Attenuation and cross talk are acceptable to determine the position of single particle shower and multihit identification For multihit analysis, further study is necessary Paint between the bars reduces cross talk, but worsens attenuation and its bar-to-bar variation O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  30. Global LHCf physics program LHCf measurement for p-Pb interactions at 3.5TeV proton energy could be easily and finely integrated in the LHCf global campaign. O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  31. Proton-remnant side – photon spectrum Small tower Big tower O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  32. Proton-remnant side – neutron spectrum Small tower Big tower 35% ENERGY RESOLUTION IS CONSIDERED IN THESE PLOTS O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  33. Proton remnant side – Invariant cross section for isolated g-rays O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  34. 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 O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  35. Lead-remnant side – multiplicityPlease remind that EPOS does not consider Fermi motion and Nuclear Fragmentation Small tower Big tower  n O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

  36. … and required statistics to complete the p/Pb physics run • Minimum required number of collision: Ncoll = 108(factor 10 more statistics wrt shown plots) • Integrated luminosity Lint = 50 mb-1 • 2106 single photons expected on p-remnant side • 35000 0 expected on same side • Assuming a pessimistic scenario with luminosity L = 1026 cm-2s-1 : • Minimum running time for physics t = 140 h (6 days) O. Adriani LHCf Status 110th LHCC Meeting, 13th June 2012

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