lhcf: physics results on forward particle production at lhc
DESCRIPTION
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 . - PowerPoint PPT PresentationTRANSCRIPT
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LHCf: physics results on forward particle production at
LHC
Oscar AdrianiUniversity of Florence & INFN Firenze
EDS Blois 2013Saariselka, September 9th, 2013
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+Physics MotivationsImpact on HECR Physics
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
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PROTON
IRON
Auger Coll. ICRC2011
10191018
Xmax distribution
Extensive air shower observation • longitudinal distribution • lateral distribution • Arrival direction
Astrophysical parameters • Spectrum• Composition• Source distribution
Air shower development
HECRs
Xmax is the depth of air shower maximum inthe atmosphere. An indicator of CR composition.
Uncertainty of hadron interaction models
Uncertainty in the interpretation of <Xmax>
High Energy Cosmic Rays
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
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④ secondary interactionsnucleon, p
① Inelastic cross section If large s: rapid developmentIf small s: deep penetrating
② Forward energy spectrum
If softer shallow developmentIf harder deep penetrating
If large k (p0s carry more energy) rapid developmentIf small k (baryons carry more energy) deep penetrating
How accelerator experiments can contribute?
③ Inelasticity k=1-Elead/Eavail
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+ Models tuning after the first LHC data
PROTON
IRON
Auger Coll. ICRC2011
10191018
Xmax as function of E and particle type
T.Pierog,Cosmic QCD 2013 conference in Paris
Pre LHC Post LHC
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+LHCf @ LHCThe experimental set-up
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+ The Large Hadron Collider (LHC)pp 450GeV+450GeV Elab ~ 2x1014eV
pp 3.5TeV+3.5TeV Elab ~ 2.6x1016eVpp 6.5TeV+6.5TeV Elab ~1017eV
ATLAS/LHCfLHCb/MoEDAL
CMS/TOTEM
ALICE
Total cross section ↔ TOTEM, ATLAS, CMS Multiplicity ↔ Central detectors Inelasticity/Secondary spectra ↔ Forward
calorimeters (LHCf, ZDCs)
R. Orava, (2007)
Full rapidity coverage!
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
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
a) University of Florence, Italyb) INFN Section of Florence, Italy c) IFAC-CNR, Florence, Italyd) IFIC, Centro Mixto CSIC-UVEG, Spaine) Ecole Polytechnique, Palaiseau, Francef) KMI, Nagoya University, Nagoya, Japang) STELAB, Nagoya University, Japanh) RISE, Waseda University, Japani) School of Science, Nagoya University, Japanj) CERN, Switzerlandk) Kanagawa University, Japanl) University of Catania, Italym) INFN Section of Catania, Italyn) LBNL, Berkeley, California, USAo) Shibaura Institute of Technology, Japan
The LHCf Collaboration
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
LHCf: location and detector layout
44X0, 1.6 lint
INTERACTION POINT
IP1 (ATLAS)
Detector IITungsten
ScintillatorSilicon
mstrips
Detector ITungsten
ScintillatorScintillating
fibers140 m 140 m
n π0
γ
γ8 cm 6 cm
Front Counter Front Counter
Arm#1 Detector20mmx20mm+40mmx40mm4 X-Y SciFi tracking layers
Arm#2 Detector25mmx25mm+32mmx32mm4 X-Y Silicon strip tracking layers
Energy resolution: < 5% for photons 30% for neutronsPosition resolution: < 200μm (Arm#1) 40μm (Arm#2)Pseudo-rapidity range:η > 8.7 @ zero Xing angleη > 8.4 @ 140urad
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
Determination of energy from total energy release
PID from shapeDetermination of the impact point
Measurement of the opening angle of gamma pairs
Identification of multiple hit
25mm Tower 32mm Tower600GeV photon
420GeV photon
Longitudinal development measured by scintillator layers
Transverse profile measured by silicon –strip layers
`
X-view
Y-view
`
Reconstruction of 0 mass:
A very clear p0 in Arm2
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
Year Beams
Beam energy
Proton equivalent
energy in the LAB (eV)
Setup
2009 p - p 450+450 GeV 4.3 1014 Arm1+Arm
22009/20
10 p - p 3.5+3.5 TeV 2.6 1016 Arm1+Arm
2
2013 p – Pb 4 TeVproton 1.3 1016 Arm2
2013 p - p 1.38+1.38 TeV 4.1 1016 Arm2
2015 p - p 6.5+6.5 TeV 9 1016 Arm1+Arm
2 upgraded
?p –
light ions
? ? ?
LHCf Physics Program
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+Inclusive photon spectrum analysis at 7 TeV and 900 GeV“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
A short review of already published results
Forward p0 spectra at 7 TeV“Measurement of forward neutral pion transverse momentum spectra for √s = 7TeV proton-proton collisions at LHC“PRD 86 (2012) 092001
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
DATA vs MC : comp. 900GeV/7TeV90
0GeV
7TeV
η>10.94 8.81<η<8.9
• None of the model nicely agrees with the LHCF data• Here we plot the ratio MC/Data for the various models• > Factor 2 difference
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
DATA : 900GeV vs 7TeV
Preliminary
Data 2010 at √s=900GeV(Normalized by the number of entries in XF > 0.1)Data 2010 at √s=7TeV (η>10.94)
900GeV vs. 7TeVwith the same PT region
Normalized by the number of entries in XF > 0.1 No systematic error is considered in both collision
energies.
XF spectra : 900GeV data vs. 7TeV data
small-η
Coverage of 900GeV and 7TeV results in Feynman-X and PT
Good agreement of XF spectrum shape between 900 GeV and 7 TeV.weak dependence of <pT> on ECMS
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
p0 PT spectra for various y bin: MC/dataEPOS gives the best agreement both for shape and yield.
DPMJET 3.04 QGSJETII-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145
0 0.6PT[GeV]
0 0.6PT[GeV] 0 0.6PT[GeV] 0 0.6PT[GeV]
0 0.6PT[GeV] 0 0.6PT[GeV]
MC/
Data
MC/
Data
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+ p0 analysis at √s=7TeV
1. Thermodynamics (Hagedron, Riv. Nuovo Cim. 6:10, 1 (1983))
2. Numerical integration actually up to the upper bound of histogram
• 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
PLB 242 531 (1990)
ylab = ybeam - y
Submitted to PRD (arXiv:1205.4578).
pT spectra vs best-fit function Average pT vs ylab
YBeam=6.5 for SPSYBeam=8.92 for7 TeV LHC
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+On going analysisNeutrons at 7 TeV pp collisionsThe 2013 p-Pb run
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+ Very big discrepancies
between models Useful measurement!
Performance for neutrons 35% Eres 1mm Position Res.
@ 1.5TeV nAnd….Detector performanceis also interaction model dependent.
Unfolding is essential to extract physics results from the measured spectra
The challenge of n analysisMC
Detector performance
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
L90%L20%
Layer[r.l.]
hadronphoton
projection along the sloped
line
L 90%
L20%
Shower development in the small
calorimeter tower
Neutron identification
• 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%L2D
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
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Small tower7 TeV pp
Large tower7 TeV pp
Preliminary n spectrum
Unfolding is in progress…..No efficiency correctionNo rapidity selectionNo unfoldingNo systematic errors
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+
3.5cm,4.0cm
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 mrad crossig 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
p Pb
IP8IP2IP1
Arm2
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
Physics in pA
Nuclear effect in the forward particle productionPhoton spectra for different impact parameters
Photon spectra at different η in p-p, p-N and p-Pb collisionsIs p-Pb good test for p-atmosphere?
p-p p-N p-Pb
QGSJET II-04All η8.81<η<8.99η>10.94
(Courtesy of S.Ostapchenko)
Please observe that the impact parameter can be obtained from Atlas Lucid, for ex.!
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
Impact points and beam center2d distribution of impact point: neutrons are more peaked
DATA
DATA
Determination of the beam center (BC)
2d gaussian fit𝑥𝐵=(1.07±0.09 )mm
𝑦𝐵=(−1.87 ±0.08 )mm
Coordinates of the beam center with respect to the expected beam center
n
n
2013p-Pb run
p-remnant side
DATA
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
Photon - y
Neutron - x
Neutron - y
Photon - x
PRELIMINARY PRELIMINARY
PRELIMINARY PRELIMINARY
Neutrons are well peaked at the beam center
Forward baryon production is important to understand the muon excess [T. Pierog, K. Werner PRL 101 171101(2008)]
and n impact point distributions (p-remnant)
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
PRELIMINAR
Y
PRELIMINARY25 mm
32 mm
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
p-Pb run: spectra
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
PRELIMINARY
PRELIMINAR
Y
p-Pb run: p0
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
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.
RHICf experiment at RHICLower collision energy, ion collisions.LOI to the RHIC committee submitted
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
LHCf: future plan
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+ 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
Physics of RHICf
Y. Fukao et al.,PLB 650 (2007)
The STAR Collaboration, PRL 97 (2006) 152302
Nuclear modification factor at d-Au 200GeV
O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+ 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 = 5 TeV 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)
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+Backups
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+Muon excess at Pierre Auger Obs.
Pierre Auger Collaboration, ICRC 2011 (arXiv:1107.4804)
Pierog and Werner, PRL 101 (2008) 171101
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 MCEPOS predicts more muon due to larger baryon production => importance of baryon measurement
O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
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+
xF = E/E0
Playing a game with air shower (effect of forward meson spectra)
E=E1+E2
E1E
2
xF = E/E0
pT
• 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
O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+ An example of filtering
π0 spectrum
photon spectrum
DPMJET3+filter
2.5x1016 eV proton~30g/cm2
Vertical Depth (g/cm2)
AUGER, ICRC 2011
EPS-HEP 2013 July 18-24
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+η
∞
8.5
What LHCf can measure
Energy spectra and Transverse momentum distribution of
Multiplicity@14TeV Energy Flux @14TeV
Low multiplicity !! High energy flux !!
simulated by DPMJET3
• 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
Front view of calorimeters @ 100μrad crossing angle
beam pipe shadow
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
Comparison wrt MC Models at 7 TeVDPMJET 3.04 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145 QGSJET II-03
Gray hatch : Systematic Errors
Magenta hatch: MC Statistical errors
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
Comparison wrt MC Models at 900 GeV
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+ h Mass Arm2 detector, all runs with zero crossing angleTrue h Mass: 547.9 MeVMC Reconstructed h Mass peak: 548.5 ± 1.0 MeVData Reconstructed h Mass peak: 562.2 ± 1.8 MeV (2.6% shift)
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+Type-I Type-II
Type-II at small tower
Type-II at large tower
Type-ILHCf-Arm1
Type-IILHCf-Arm1
LHCf-Arm1Data 2010
BG
Signal
Preliminary
•Large angle•Simple•Clean•High-stat.
•Small angle•large BG•Low-stat., but can cover•High-E•Large-PT
π0 analysis at √s=7TeVSubmitted to PRD (arXiv:1205.4578).
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
p0 Data vs MC
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
p0 Data vs MC 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 p0 yield is generally small
qgsjet II-03 predicts p0 spectra softer than LHCf data
epos 1.99 shows the best overall agreement with the LHCf data.
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.
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+MC study of n response
O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
E vs. <Evis> at centerPosition resolution
Correction for position dependent shower leakage
Energy resolution (uniform incident on calorimeters)
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
Proton remnant side – Photon spectra
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
Proton remnant side - Neutron spectra
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
+ Proton-remnant side – p0
We can detect p0!
Important tool for energy scale
And also for models check…..
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+Lead-remnant side – multiplicityPlease remind that EPOS does not consider Fermi motion and Nuclear Fragmentation
n
Small tower Big tower
O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
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O. Adriani LHCf physics results on forward particle production at LHC Saariselka, September 9th, 2013
Common trigger with ATLAS
LHCf forced to trigger ATLAS Impact parameter may be determined by ATLAS Identification of forward-only events
MCimpact parameter vs. # of particles in ATLAS LUCID