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Latest LHCf physics results

Oscar Adriani University of Florence & INFN Firenze. Latest LHCf physics results. ICHEP 2014 Valencia , July 4 th , 2014. Physics Motivations. Impact on HECR Physics. High Energy Cosmic Rays. HECRs. Extensive air shower observation . Longitudinal distribution

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Latest LHCf physics results

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  1. Oscar Adriani University of Florence & INFN Firenze Latest LHCf physics results ICHEP 2014 Valencia, July 4th, 2014

  2. Physics Motivations Impact on HECR Physics

  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 Xmaxis the depth of air shower maximum inthe atmosphere. An indicator of CR composition. Uncertainty of hadron interaction models Uncertainty in the interpretation of <Xmax> O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  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 Latest LHCf physics results Valencia, July 4th, 2014

  5. Models tuning after the first LHC data Xmaxas function of E and particle type Significant reduction of differences btw different hadronic interaction models!!! O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  6. LHCf @ LHC The experimental set-up

  7. 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 Latest LHCf physics results Valencia, July 4th, 2014

  8. LHCf ‘analysis matrix’ O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  9. Latestanalysis Neutrons in 7 TeV ppcollisions p0 in 5.02 TeV p-Pbcollisions

  10. The challenge of neutron analysis • Performance for 1.5 TeV neutrons: • DE/E ~35%-40% • Dx ~ 1mm • And…. Detector performance is also interaction model dependent! • Unfolding is essential to extract physics results from the measured spectra • Physics measurement important to try to solve the ‘Muoneccess’ observed from the ground based HECR experiments O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  11. Inclusive neutron spectra (7 TeV pp) Before unfolding After unfolding Very large high energy peak in the h>10.76 (predicted only by QGSJET)  Small inelasticity in the very forward region! O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  12. p IP1 IP2 IP8 Arm2 Pb The 2013 p-Pb run at sNN = 5.02 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 mradcrossing angle • 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 Latest LHCf physics results Valencia, July 4th, 2014

  13. proton proton Pb impactparameter : b LHCf @ pPb 5.02 TeV: p0 analysis (Soft) QCD :central and peripheral collisions Ultra peripheral collisions :virtual photons from rel. Pb collides a proton Central collisions Peripheral collisions Estimation of momentum distribution of the UPC induced secondary particles (Lab frame+Boost): 1. energy distribution of virtual photons is estimated by the Weizsacker Williams approximation
2. photon-proton collisions are simulated by the SOPHIA model (Eγ > pion threshold) Dominant channel to forward p0is Comparisonwith soft-QCD Break downof UPC About half of the observed π0originate from UPC About half is from soft-QCD Need to subtract UPC component O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  14. p0event reconstruction in p-Pb collisions 1. Search for two photons 2. BG subtraction by sideband travel in beam pipe (140m) 3. Unfolding the smeared pT spectra andcorrection for geometrical inefficiency 4. Subtraction of the UPC component π0 detection efficiencyp-Pb √s=5.02TeV UPC MC (x0.5) LHCf data O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  15. Inclusive p0pT spectra in p-Pb at 5.02 TeV • LHCf data in p-Pb (filled circles) show good agreement with DPMJET and EPOS. • LHCf spectra in p-Pb are clearly harder than the LHCf data in p-p at 5.02 TeV (shaded area, spectra multiplied by 5). The latter is interpolated from the results at 2.76 TeV and 7 TeV. O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  16. Nuclear modification factor in p-Pb at 5.02 TeV • Both LHCf and MCs show strong suppression. • NMF grows with increasing pT, as can be expected by the pT spectrum that is softer in p-p 5 TeV than in p-Pb 5 TeV collisions O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  17. Conclusions • Very forward p0production in p-Pb collision has been measured by LHCf • Soft-QCD component of the measured p0production overall agrees with DPMJET 3.04 and EPOS 1.99. • Strong suppression of p0production is found in p-Pb collision which is consistent with predictions of DPMJET, EPOS and QGSJET II-03 • Large amount of high energy neutrons exists in very forward region of p-p collisions, leading to small inelasticity • Detector setup for future runs is ongoing smoothly: • LHC@13 TeV in 2015 • 510 GeV polarized p-p RHIC run in 2016 has been proposed to RHIC PAC. We are waiting for official answer O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  18. Backup slides O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  19. The LHCf Collaboration • O.Adriania,b, L.Bonechib, E.Bertia,b, M.Bongia,b, G.Castellinic,b, R.D’Alessandroa,b,M.DelPretea,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, A.Tiberioa,b, 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 Latest LHCf physics results Valencia, July 4th, 2014

  20. UPC subtraction O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  21. 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 Latest LHCf physics results Valencia, July 4th, 2014

  22. Derivation of p0pT spectra in p-p at 5.02 TeV 1. Thermodynamics (Hagedornmodel) The pT spectra in “p-p at 5.02TeV” are obtained by the Gauss distribution with the above <pT> and absolute normalization. 2. Gauss distribution 22 O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  23. The importance of neutrons in the very forward region • Motivations: • Inelasticity measurement: k=1-pleading/pbeam • Muonexcess at Pierre Auger Observatory • cosmic rays experiment measure HECR energy from muon number at ground and florescence light • 20-100% more muons than expected have been observed Number of muons depends on the energy fraction of produced hadron Muon excess in data even for Fe primary MC EPOS predicts more muon due to larger baryon production importance of baryon measurement R. Engel O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  24. p-Pb run: p0 PRELIMINARY PRELIMINARY O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  25. 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 Latest LHCf physics results Valencia, July 4th, 2014

  26. 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 Latest LHCf physics results Valencia, July 4th, 2014

  27. 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 Latest LHCf physics results Valencia, July 4th, 2014

  28. 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 Latest LHCf physics results Valencia, July 4th, 2014 0 PT[GeV] 0.6

  29. p0 Data vsMC at 7 TeV cm O. Adriani Latest LHCf physics results Valencia, July 4th, 2014

  30. 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 Latest LHCf physics results Valencia, July 4th, 2014

  31. 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 Latest LHCf physics results Valencia, July 4th, 2014

  32. 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 Latest LHCf physics results Valencia, July 4th, 2014 RHICf experiment at RHIC Lower collision energy, ion collisions.LOI to the RHIC committee submitted

  33. 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 Latest LHCf physics results Valencia, July 4th, 2014

  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 Latest LHCf physics results Valencia, July 4th, 2014

  35. 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 Latest LHCf physics results Valencia, July 4th, 2014

  36. 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 Latest LHCf physics results Valencia, July 4th, 2014

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