The LHCf (LHC forward) experiment ~ a collider experiment dedicated - - PowerPoint PPT Presentation

The LHCf (LHC forward) experiment

~ a collider experiment dedicated for ultra-high-energy cosmic-ray physics ~ Koji Noda

for the LHCf Collaboration

INFN (Section of Catania), Italy 6th European Summer School on Experimental Nuclear Astrophysics, Acireale, Italy, 18-27 Sep 2011

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Very-high-energy cosmic ray specrum

M Nagano

New Journal of Physics 11 (2009) 065012

LHC

SPS

AUGER

Cosmic ray spectrum LHC SPS

(UA7)

10^17eV CR (fixed target) <=> cm energy at LHC (7+7TeV) >10^15eV: detected with air-showers, but many unknowns

Tevatron

Tevatron

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• 1. Inelastic cross section
• 2. Forward energy spectrum

If large k rapid development If small k deep penetrating If large rapid development If small deep penetrating

• 4. 2ndary interactions
• 3. Inelasticity k

(1-Eleading)/E0

If softer rapid development If harder deep penetrating

Air-sho shower er develop elopment ment

Ha Hadr dron

• n in

interaction action mo mode del

• ma

majo jor r sou

• urce

rce of

• f unc

ncertainty tainty -

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LHC data is expected to reduce this uncertainty

rapid development deep penetrating

Wha hat t sh shou

• uld

d be be measu sured? red?

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Multiplicity Energy Flux All particles neutral

Most of the energy flows into very forward

sqrt(s)=14TeV Elab=1017eV

multiplicity and energy flux at LHC 14TeV collisions pseudo-rapidity; = -ln(tan( /2))

K.Fukatsu, T.Iso, Y.Itow, K.Kawade, T.Mase, K.Masuda, Y.Matsubara, G.Mitsuka, Y.Muraki, T.Sako, K.Suzuki, K.Taki Solar-Terrestrial Environment Laboratory, Nagoya University, Japan H.Menjo Kobayashi-Maskawa Institute, Nagoya University, Japan K.Yoshida Shibaura Institute of Technology, Japan K.Kasahara, Y.Shimizu, T.Suzuki, S.Torii Waseda University, Japan T.Tamura Kanagawa University, Japan M.Haguenauer Ecole Polytechnique, France W.C.Turner LBNL, Berkeley, USA O.Adriani, L.Bonechi, M.Bongi, R.D’Alessandro, M.Grandi, P.Papini, S.Ricciarini, G.Castellini INFN, Univ. di Firenze, Italy K.Noda, A.Tricomi INFN, Univ. di Catania, Italy J.Velasco, A.Faus IFIC, Centro Mixto CSIC-UVEG, Spain A-L.Perrot CERN, Switzerland

The LHCf Collaboration

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Det Detec ector

• r Loc
• cati

tion

• n

7

140m

LH LHCf Cf Det Detec ector

• rs

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Arm#1 Detector 20mmx20mm+40mmx40mm 4 XY SciFi+MAPMT Arm#2 Detector 25mmx25mm+32mmx32mm 4 XY Silicon strip detectors

Imaging sampling shower calorimeters  Two independent calorimeters in each detector (Tungsten 44r.l., 1.6 , sampling with plastic scintillators)  4 position sensitive layers distributed in the calorimeters

De Detec ector

• r ph

photos

• s

Arm#1 Detector Arm#2 Detector

Ev Event ent ca catego gory y of

• f LH

LHCf Cf

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Single hadron event Pi-zero event (photon pair) Single photon event

Ex Expe pect cted ed Results ults at 14 TeV Col

• llision

sions

(MC assuming 0.1nb-1 statistics)

Detector response not considered

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Single photon Single photon at different Single neutron

Summar mmary y of Op Opera rations tions in 200 009 9 and 2010

With Stable Beam at 900 GeV

Total of 42 hours for physics About ut 100 k showers events in Arm1+Arm2

With Stable Beam at 7 TeV

Total of 150 hours for physics with different setups

Different vertical position to increase the accessible kinematical range Runs with or without beam crossing angle

400 M shower events in Arm1+Arm2 1 M 0 events in Arm1+Arm2

Status

Com

• mple

leted ed program am for 900 GeV and 7 TeV Remo moved ed det etect ector

• rs

s from m tun unnel nel in Jul uly 2010

Post-calib calibrat ation

• n beam

m test in Octob

• ber

er 2010

Up Upgrade ade on-going going to more re rad-ha hard d det etect ector

• rs

s for 14TeV in 2014

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Arm1

0 stat.

EM EM sho hower er and nd

0 id

identif ntification ication

• A Pi0 candidate event
• 599GeV & 419GeV photons in 25mm

and 32mm tower, respectively

• M = x sqrt(E1xE2)

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Event sample in Arm2

Longitudinal development Lateral development

Silicon X Silicon Y Small Cal. Large Cal. Invariant mass of photon pairs

Comparison with models, coming soon

Ph Photon

• n spe

pect ctra ra at t 7TeV eV co coll llisions isions



The simplest photon spectra by Arm1 & Arm2 at common rapidity



Nine =

ine x int(Ldt) (

ine = 71.5mb assumed; consistent with recent ATLAS result)



e/h shower separation based on the longitudinal shower development

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(Published in PLB, ArXiv:1104:.5294v2 [hep-ex])

=> Combined & compared with MC models

Comparison between Models

DPMJET 3.04 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145 QGSJET II-03

Gray hatch : Systematic Errors Magenta hatch: MC Statistical errors

• None of the models nicely describe the LHCf data in the

whole energy range (100 GeV – 3.5 TeV).

• Very big discrepancy in the high energy region (>2 TeV)
• Significant improvement of the models is possible with model developers

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Upgr Upgrade ade for

• r 14T

4TeV eV

for rad-hardness for improvement of energy reconstruction

Silicon layer positions in Arm2 detector

X,Y X,Y X,Y X,Y

X,Y X,Y X X Y Y

Energy reconstruction with the Si layers is also useful!

higher luminosity is expected in the 14TeV runs

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Kawade+ (2011)

Ana naly lysis is of

• f th

the e Si Si la layer ers (my ongoing work)

 Energy reconstruction with the Si data

 complementary to that with the scintillators  for separation of multi-hits in 1 tower

 It requires

 calibration (ADC count -> energy deposit -> incident energy)  correction for the saturation effects (only for high-E events)

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A (gain calibration) Test beam at SPS in 2010

• 100, 150, 175, 200GeV e-
• comparison with MC
• averaged over energies

=> Gain: 42.8 ADC/MeV, +0.5%-1.0% (sys.)

A B

B (incident E reconstruction with MC)

Energy of incident : 50, 100, 200, 500GeV, 1, 2, 3TeV

errors: sys. from diff. methods

Refinement of the methods is ongoing

dE-E relation

dE on Si => E with ~3% precision

a multi-hit events in a calorimeter

Su Summ mmar ary & P & Pros

• spe

pects ts

 LHCf is a cosmic-ray dedicated experiment in LHC  DAQ in LHC sqrt(s) = 7 TeV pp collisions completed  Analyses

 Photon spectra at sqrt(s) = 7TeV (published in PLB)  Photon spectra at sqrt(s) = 0.9 TeV 

0 spectra

 Impact on EAS  Energy reconstruction improvement  PT spectra, Hadron spectra, test for LPM effect  Correlation with central production (joint analysis with ATLAS)

 Measurements

 LHC sqrt(s) = 14 TeV pp (scheduled after 2014; rad-hard upgrade on going)  in study: LHC p-Pb (2012?), possibility in the other colliders  N-p, N-N, N-Fe (N; Nitrogen) in future?

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Completed In progress In consideration

Still many dishes to enjoy!!

Backup

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Very forward – connection to low-x physics

(slides by Y. Itow)

 Very forward region : collision of a low-x parton with a large-x parton  Small-x gluon become dominating in higher energy collision by self

interaction.

 But they may be saturated (Color Glass Condensation)

Low-x high-x Very forward

Naively CGC-like suppression may

• ccur in very forward at high energy

g However situation is more complex (not simple hard parton collisions, but including soft + semi-hard ) soft semi- hard hard

Physics of MCs (K. Werner, EDS09, CERN)

Nonlinear effects in MCs

all slides are by

• K. Werner, EDS09, CERN

Non-linear effects are implemented in a phenomenological manner

air-shower development: Xmax

p 1019

19 eV

eV

FrontCounter

2 fixed Front Counters installed in front of Arm1 and Arm2 They will not move with Arm1 and Arm2 segmented in 2 x- and 2 y-slices Very useful to check the beam quality

Alessia Tricomi University and INFN Catania EPS 09, Krakow 16-22 July 2009

Acceptance eptance

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π0

Photon at √s =14TeV pp collision

2010 operation at √s=7TeV

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106 107 108 # of showers Detector removed

High luminosity (L=3~20e29cm2s-1) (1e11ppb, b*=3.5m,Nb=1~8)

100 rad crossing

Arm1

0 stat.

Low luminosity (L=2~10e28cm2s-1) (1~2.5e10ppb, =2m,Nb=1~4) No crossing angle

500K 1000K # of

900GeV

4/1 5/27 7/22 4/4 5/30 7/25

Parti ticle le ID

 EM and hadronic shower separation based on the

longitudinal shower development

 Nphoton/Nhadron ratio will give a good information for model  Response of detectors to hadrons in study

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Gam ame wit with h mo modi dified ied me meson

• n spe

pect ctrum rum

Play within the model uncertainty Play within the LHCf error

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