LHCf: stato e programmi

1. LHCf: stato e programmi Oscar Adriani CSN1,Torino, 27 settembre 2012

2. Introduction and contents • Analyses • p0 paper accepted by PRD • 900 GeVg paper published on PLB • Short spot on other analyses • Arm1 preparation for 14 TeV • Beam test at SPS (August-September 2012) • Arm2 preparation for p/Pb2013run

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

4. π0 analysis: PT spectra for different rapidity bins “Measurement of forward neutral pion transverse momentum spectra for √s = 7TeV proton-proton collisions at LHC“ ‘Accepted’ by PRD

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

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

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

8. π0 results: Data vs MC

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

10. 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.

11. <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

12. 900 GeV inclusive g spectra “Measurement of zero degree single photon energy spectra for √s = 900 GeV proton-proton collisions at LHC“ PLB 715 (2012) 298 CERN-PH-EP-2012-048

13. Comparison wrt MC Models at 900 GeV

14. ganalysis: Comparison btw 900 GeVand 7 TeVspectra Coverage of the photon spectra in the plane Feynman-X vs PT small-η = Large tower big-η =Small tower

15. 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

16. 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

17. Neutron and K0(very preliminary…) analyses

18. 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

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

20. 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

21. K0 analysis

22. K0 Acceptance

23. Status of the LHCf preparation for 14 TeV

24. LHCfpreparation 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) has been done in June 2012 • Arm1 has beenre-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

26. Beam test at the SPS • Long beam test has been conducted from August 17th to September 4th in the H2 SPS area • Muons, 50-250 GeV electrons, 350 GeV protons • More than 1 TB of data • Main goals: • Energy scale of upgraded Arm1 detector • Check of energy scale of not upgraded Arm2 for the p/Pb run • Test of the solution to improve the silicon saturation for 14 TeV run • Check of the temperature dependence of the absolute energy scale both for Arm1 and Arm2 • Very successful beam test!

27. Test of new silicon pattern bonding • Problem: saturation of the silicon electronics for Eg > 1.5 TeV • Pace3 dynamic range is not enough to sustain such a huge energy release • Not a problem for 3.5+3.5 TeV runs • Software corrections based on the different PACE3 samples allow to increase saturation up to 2.5/3 TeV • Become an issue for 7+7 TeV run • We will change the silicon sensors position to improve the silicon only energy resolution…. • We developed a new idea to hardware improve the saturation level

28. Different silicon bonding scheme 80 mm implant pitch 160 mm readout pitch Silicon sensor Not used Readout Floating Normal configuration Readout Readout New configuration Ground Readout New silicon Arm2 detector The beam test setup Pb (40mm) e-, 200 GeV/c

29. New Silicon Module results (Quick analysis) Histogram of peak values Silicon Lateral distribution Normal New #Strip Clearly the pulse height in the region of new configuration were reduced by a factor of 1.5 ~ 1.7 (we could naively expect 2) The modification works fineto enlarge the silicon dynamic range

30. Arm2 Pi0 Mass v.s. Temperature at LHC Remember the 3.8% Mass Shift that was longly discussed….

31. Temperature test and control at SPS During the beam test, we carefully controlled the temperature of the detector with a chiller We waited for some hours until the temperature was very stable (< 0.1 degree / hour) Water Chiller

32. Temperature test (Arm2) Thermometer in Arm2 33 28 23 Chiller temperature 18 Check the temperature dependency of the energy scale by changing the chiller temperature to 18, 23, 28, 33 degrees.

33. Energy scale temperature dependence(Arm2) The temperature coefficient isconsistent with the R7400U catalog value (-0.20% /C) We could confirm that there is a dependence of energy scale on the temperature. Compatible with 3.8% mass shift???? To be checked

34. 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 are continuing discussions with ATLAS for trigger and data exchange, to get the maximum physics outcome for the data, following the LHCC recommendation • Arm2 will be brought back to Florence after the p/Pb run completion (special transport will be necessary because of the slight radioactivity)

37. Miscellanea…. I • 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 was under discussion… • Please stand by a little bit to see how things are evolving!!!! • We have a new Japanese expert post doc that will stay in Italy for 2 years paid by Japan

38. Miscellanea II:Working together with MC model developers • Since the first paper we are in strict connection with model developers (EPOS,QGSJET, SYBILL etc.) • We have taken part to several meetings/workshops • We are contributing to the tuning of the model to LHCf data • We are also involved in the MCPLOTS/RIVET project (http://mcplots.cern.ch) • a simple browsable repository of MC (Monte Carlo) plots comparing High Energy Physics event generators to a wide variety of available experimental data, for tuning and reference purposes

39. Miscellanea III:Working together with other LHC MC contacts • Since last year we are involved in one of the WG of the MC4LHC project • A new WG is now starting to focus on astroparticle physics connection with contact persons from each LHC experiments • A. Tricomi, T. Sako • Set up and organize a workshop

40. 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 consentircila 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

41. Miscellanea V: Missioniestere • Ad Aprile 2012 la CSN1 ci avevasbloccato 35 kE di MissioniEsterecheerano SJ al run p/Pb • Datocheil run p/Pbèstatospostato al 2013, restituiamoalla CSN1 27 kE di ME (21 kE da Firenze e 6 kE da Catania) • Cerchiamo di effettuarepiùlavoripossibilenel 2012 • Setup di control room e DAQ • Test di interfaccia con la macchina • Installazionemeccanicanel tunnel • Con la ragionevolesperanzache ci venganoriassegnati per il 2013!!!!!!

42. Conclusions • The analysis work is nicely going on • Very important and tight contacts with the theorists and the model developers to maximize the outcome of the LHCf results • Arm1 upgrade has been completed • Arm2 is ready to be installed for the 2013 p/Pb run • Very successful test beam has been completed in summer 2012 • Arm2 upgrade will be completed in 2013 • Ready to take data at 14 TeV • And…. Possible Light Ions runs at RHIC/LHC are under investigation

43. Spares slides

44. Temperature dependency (Arm1) The temperature dependency has been also checked for Arm1.The coefficient of GSO may be bigger than PMT, about - 0.5% / degree.Compared the histograms of dE in each layer at 18, 23, 28, 33 chiller temperatures. 18 23 28 33 T_Chiller

45. Layer 03 Layer 04 Layer 05 Layer 06 The coefficient is between 0.17% degree and 0.45% / degree.Slightly bigger than Arm2, but not so serious.

46. 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

47. 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)

48. 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.

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

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