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LHCf: physics results on forward particle production at LHC

Oscar Adriani University of Florence & INFN Firenze. LHCf: physics results on forward particle production at LHC. EDS Blois 2013 Saariselka , September 9 th , 2013. Physics Motivations. Impact on HECR Physics. High Energy Cosmic Rays. HECRs. Extensive air shower observation .

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LHCf: physics results on forward particle production at LHC

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  1. Oscar Adriani University of Florence & INFN Firenze LHCf: physics results on forward particle production at LHC EDS Blois 2013 Saariselka, September 9th, 2013

  2. Physics Motivations Impact on HECR Physics O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  3. High Energy Cosmic Rays HECRs Extensive air shower observation • longitudinal distribution • lateral distribution • Arrival direction Air shower development Astrophysical parameters • Spectrum • Composition • Source distribution Xmaxdistribution PROTON Auger Coll. ICRC2011 Xmaxis the depth of air shower maximum inthe atmosphere. An indicator of CR composition. Uncertainty of hadron interaction models IRON 1018 1019 Uncertainty in the interpretation of <Xmax> O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  4. How accelerator experiments can contribute? ① Inelastic cross section If larges: rapid development If small s: deep penetrating ④ secondary interactions nucleon, p ② Forward energy spectrum If softer shallow development If harder deep penetrating Inelasticity k=1-Elead/Eavail If large k (p0s carry more energy) rapid development If small k (baryons carry more energy) deep penetrating O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  5. Models tuning after the first LHC data Xmaxas function of E and particle type Post LHC Pre LHC PROTON Auger Coll. ICRC2011 IRON 1018 1019 T.Pierog, Cosmic QCD 2013 conference in Paris O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  6. LHCf @ LHC The experimental set-up O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  7. The Large Hadron Collider (LHC) pp450GeV+450GeV Elab~ 2x1014eV pp3.5TeV+3.5TeV Elab~ 2.6x1016eV pp 6.5TeV+6.5TeV Elab~1017eV • Total cross section ↔ TOTEM, ATLAS, CMS • Multiplicity ↔ Central detectors • Inelasticity/Secondary spectra ↔Forward calorimeters (LHCf, ZDCs) CMS/TOTEM Full rapidity coverage! ALICE LHCb/MoEDAL ATLAS/LHCf R. Orava, (2007) O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  8. The LHCf Collaboration • O.Adriania,b, L.Bonechib, M.Bongia, G.Castellinic,b, R.D’Alessandroa,b,M.Haguenauere, Y.Itowf,g, K.Kasaharah, K. Kawadeg, Y.Makinog, K.Masudag, Y.Matsubarag, E.Matsubayashig, H.Menjoi, G.Mitsukag, Y.Murakig, P.Papinib, A.-L.Perrotj, D.Pfeifferj,S.Ricciarinic,b, T.Sakog, Y.Shimitsuh, Y.Sugiurag, T.Suzukih, T.Tamurak, S.Toriih, A.Tricomil,m, W.C.Turnern,K.Yoshidao, Q.Zhoug • University of Florence, Italy • INFN Section of Florence, Italy • IFAC-CNR, Florence, Italy • IFIC, Centro Mixto CSIC-UVEG, Spain • EcolePolytechnique, Palaiseau, France • KMI, Nagoya University, Nagoya, Japan • STELAB, Nagoya University, Japan • RISE, Waseda University, Japan • School of Science, Nagoya University, Japan • CERN, Switzerland • Kanagawa University, Japan • University of Catania, Italy • INFN Section of Catania, Italy • LBNL, Berkeley, California, USA • Shibaura Institute of Technology, Japan O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  9. 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 LHCf: location and detector layout Detector II Tungsten Scintillator Silicon mstrips Detector I Tungsten Scintillator Scintillatingfibers INTERACTION POINT IP1 (ATLAS) Front Counter Front Counter 44X0, 1.6 lint Energy resolution: < 5% for photons 30% for neutrons Position resolution: < 200μm (Arm#1) 40μm (Arm#2) Pseudo-rapidity range: η > 8.7 @ zero Xing angle η > 8.4 @ 140urad O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  10. A very clear p0 in Arm2 Longitudinal development measured by scintillator layers Determination of energy from total energy release PID from shape 25mm Tower 32mm Tower 600GeV photon 420GeV photon Transverse profile measured by silicon –strip layers ` X-view Determination of the impact point Measurement of the opening angle of gamma pairs Identification of multiple hit Y-view ` Reconstruction of 0 mass: O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  11. LHCf Physics Program O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  12. A short review of already published results Inclusive photon spectrum analysis at 7 TeV and 900 GeV Forward p0 spectra at 7 TeV “Measurement of zero degree single photon energy spectra for √s = 7 TeV proton-proton collisions at LHC“ PLB 703 (2011) 128 “Measurement of zero degree single photon energy spectra for √s = 900 GeV proton-proton collisions at LHC“ PLB 715 (2012) 298 “Measurement of forward neutral pion transverse momentum spectra for √s = 7TeV proton-proton collisions at LHC“ PRD 86 (2012) 092001 O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  13. DATA vs MC : comp. 900GeV/7TeV • None of the model nicely agrees with the LHCF data • Here we plot the ratio MC/Data for the various models • > Factor 2 difference η>10.94 8.81<η<8.9 7TeV 900GeV O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  14. DATA : 900GeVvs 7TeV Coverage of 900GeV and 7TeV results in Feynman-X and PT XF spectra : 900GeV data vs. 7TeV data 900GeVvs. 7TeVwith the same PT region Preliminary small-η Data 2010 at √s=900GeV (Normalized by the number of entries in XF > 0.1)Data 2010 at √s=7TeV (η>10.94) • 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 physics results on forward particle production at LHC Saariselka, September 9th, 2013

  15. p0 PT spectra for various y bin: MC/data 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 0 PT[GeV] 0.6 0 PT[GeV] 0.6 0 PT[GeV] 0.6 MC/Data 0 PT[GeV] 0.6 0 PT[GeV] 0.6 O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013 0 PT[GeV] 0.6

  16. p0analysis at √s=7TeV Submitted to PRD (arXiv:1205.4578). pT spectra vs best-fit function Average pT vs ylab PLB 242 531 (1990) YBeam=6.5 for SPS YBeam=8.92 for7 TeV LHC ylab = ybeam - y 1. Thermodynamics (Hagedron, Riv. NuovoCim. 6:10, 1 (1983)) • Systematic uncertainty of LHCf data is 5%. • Compared with the UA7 data (√s=630GeV) and MC simulations (QGSJET, SIBYLL, EPOS). • Two experimental data mostly appear to lie along a common curve→ no evident dependence of <pT> on ECMS. • Smallest dependence on ECMS is found in EPOS and it is consistent with LHCf and UA7. • Large ECMS dependence is found in SIBYLL 2. Numerical integration actually up to the upper bound of histogram O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  17. On going analysis Neutrons at 7 TeV ppcollisions The 2013 p-Pb run O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  18. The challenge of n analysis MC • Very big discrepancies between modelsUseful measurement! • Performance for neutrons • 35% Eres • 1mm Position Res. @ 1.5TeV n And…. Detector performanceis also interaction model dependent. • Unfolding is essential to extract physics results from the measured spectra Detector performance O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  19. Neutron identification L20% L90% • Particle Identification with high efficiency and small contamination is necessary • A 2D method based on longitudinal shower development is used • L20%(L90%): depth in X0 where 20% (90%) of the deposited energy is contained • L2D=L90%-0.25 L20% • Mean purity in the 0-10 TeV range: 95% • Mean efficiency: ~90% Shower developmentin the small calorimeter tower projection along the sloped line Layer[r.l.] L90% hadron photon L20% L2D O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  20. Preliminary n spectrum ` Large tower 7 TeVpp Small tower 7 TeVpp No efficiency correction No rapidity selection No unfolding No systematic errors Unfolding is in progress….. O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  21. p IP1 IP2 IP8 Arm2 Pb The 2013 p-Pb run at sNN = 5 TeV • 2013 Jan-Feb for p-Pb/Pb-p collisions • Installation of the only Arm2 at one side (silicon tracker good for multiplicity) • Data both at p-side (20Jan-1Feb) and Pb-side (1fill, 4Feb), thanks to the swap of the beams • Details of beams and DAQ • L = 1x1029 – 0.5x1029cm-2s-1 • ~200.106 events • b* = 0.8 m, 290 mradcrossigangle • 338p+338Pb bunches (min.DT = 200 ns), 296 colliding at IP1 • 10-20 kHz trig rate downscaled to approximately 700 Hz • 20-40 Hz ATLAS common trig. Coincidence successful! • p-p collisions at 2.76 TeV have also been taken 3.5cm,4.0cm O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  22. Physics in pA QGSJET II-04 All η 8.81<η<8.99 η>10.94 p-p p-N p-Pb Nuclear effect in the forward particle production Photon spectra for different impact parameters Please observe that the impact parameter can be obtained from Atlas Lucid, for ex.! (Courtesy of S.Ostapchenko) Photon spectra at different η in p-p, p-N and p-Pb collisions Is p-Pbgood test for p-atmosphere? O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  23. Impact points and beam center 2d distribution of impact point: neutrons are more peaked 2013 p-Pb run  n p-remnant side DATA Determination of the beam center (BC) DATA 2d gaussian fit Coordinates of the beam center with respect to the expected beam center DATA n O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  24. g and n impact point distributions (p-remnant) PRELIMINARY PRELIMINARY Photon - x Photon - y Neutron - x Neutron - y PRELIMINARY PRELIMINARY Forward baryon production is important to understand the muon excess [T. Pierog, K. Werner PRL 101 171101(2008)] Neutrons are well peaked at the beam center O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  25. p-Pbrun: g spectra • Detailed simulations with the available hadronic interaction models are on-going for a comparison with data • Transportation of secondary particles from IP to detector, beam pipe structure, magnetic fields along the path and detector’s response will be taken into account • Vertical bars: statistical errors PRELIMINARY 32 mm PRELIMINARY 25 mm O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  26. p-Pb run: p0 PRELIMINARY PRELIMINARY O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  27. LHCf: future plan p-p at 13TeV (2015) Main target: measurement at the LHC design energy.Study of energy scaling by comparison with √s = 900 GeV and 7 TeV data Upgrade of the detectors for radiation hardness. p-light ions (O, N) at the LHC (2019?) It allows studying HECR collisions with atmospheric nuclei. • p-p collisions: • Max. √s = 500 GeV • Polarized beams • Ion collisions: • Au-Au, d-Au • Max. √s = 200 GeV • Possible, d-O,N (p-O,N)Cosmic ray – Air @ knee energy. 10cm detector O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013 RHICf experiment at RHIC Lower collision energy, ion collisions.LOI to the RHIC committee submitted

  28. Physics of RHICf • Physics of RHICf • Energy Scaling of Very Forward at p-p √s=500GeV • Measurement at p-light ion collisions (p-O) √sNN=200GeV • Asymmetry of Forward Neutron with polarized beams • LOI submitted to the RHIC committee and nicely appreciated • More news soon Nuclear modification factor at d-Au 200GeV The STAR Collaboration, PRL 97 (2006) 152302 Y. Fukaoet al.,PLB 650 (2007) O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  29. Conclusions • LHCf is a small experiment at LHC dedicated to forward physics • Important for Very High Energy Cosmic-Ray (VHECR) Physics • We have published spectra of photons and neutral pions for pp interactions at s = 900 GeV and s = 5TeV • None of the hadronic interaction models that we have considered can reproduce the data within the errors, but data lie anyway between the models • On-going data analysis for the hadronic component (neutrons) • p-Pb run at the beginning of 2013 • Successful data taking in p-remnant and Pb remnant side • Common operations with ATLAS (trigger exchange) • On-going data analysis (some hints for interesting results!!!) • Future plan • Continue and finalize the on-going data analysis (start also ATLAS/LHCf common analysis) • Complete the upgrade of the detectors for radiation hardness • Data taking for pp collisions at s = 13 TeV (2015) • Run p-light ions at LHC (2019?) • Operations at RHIC (p-O or p-N at lower energies) O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  30. Backups O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  31. Muon excess at Pierre Auger Obs. • Auger hybrid analysis • event-by-event MC selection to fit FD data (top-left) • comparison with SD data vs MC (top-right) • muon excess in data even for Fe primary MC • EPOS predicts more muon due to larger baryon production • => importance of baryon measurement Pierre Auger Collaboration, ICRC 2011 (arXiv:1107.4804) Pierog and Werner, PRL 101 (2008) 171101 O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  32. Playing a game with air shower (effect of forward meson spectra) • DPMJET3 always over-predicts 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 O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  33. An example of filtering Vertical Depth (g/cm2) DPMJET3+filter photon spectrum ~30g/cm2 π0 spectrum 2.5x1016eV proton AUGER, ICRC 2011 O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013 EPS-HEP 2013 July 18-24

  34. η 8.5 ∞ Front view of calorimeters @ 100μrad crossing angle What LHCf can measure beam pipe shadow Energy spectra and Transverse momentum distribution of • Gamma-rays (E>100GeV,dE/E<5%) • Neutral Hadrons (E>a few 100 GeV, dE/E~30%) • π0 (E>600GeV, dE/E<3%) at pseudo-rapidity range >8.4 Multiplicity@14TeV Energy Flux @14TeV High energy flux !! Low multiplicity !! simulated by DPMJET3 O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  35. Comparison wrt MC Models at 7 TeV DPMJET 3.04 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145 QGSJET II-03 Magenta hatch: MC Statistical errors Gray hatch : Systematic Errors O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  36. Comparison wrt MC Models at 900 GeV O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  37. h Mass Arm2 detector, all runs with zero crossing angle True hMass: 547.9 MeV MC Reconstructed hMass peak: 548.5 ± 1.0 MeV Data Reconstructed hMass peak: 562.2 ± 1.8 MeV (2.6% shift) O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  38. 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 physics results on forward particle production at LHC Saariselka, September 9th, 2013

  39. p0 Data vs MC O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  40. p0 Data vs MC • dpmjet3.04 &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 physics results on forward particle production at LHC Saariselka, September 9th, 2013

  41. MC study of n response E vs. <Evis> at center Energy resolution (uniform incident on calorimeters) Position resolution Correction for position dependent shower leakage O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  42. O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  43. Proton remnant side – Photonspectra O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  44. Proton remnant side - Neutronspectra O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  45. Proton-remnant side – p0 We can detect p0! Important tool for energy scale And also for models check….. O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  46. Lead-remnant side – multiplicityPlease remind that EPOS does not consider Fermi motion and Nuclear Fragmentation Small tower Big tower  n O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

  47. Common trigger with ATLAS MC impact parameter vs. # of particles in ATLAS LUCID LHCf forced to trigger ATLAS Impact parameter may be determined by ATLAS Identification of forward-only events O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013

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