P L H C 2 0 1 1 P e r u g i a , J u n e 6 , 2 - - PowerPoint PPT Presentation

P L H C 2 1 1 P e r u g i a , J u n e 6 , 2 1 1

C O N T E N T S

• Ph

Physics mo ysics motiv tivations tions

• Ultra High Energy Cosmic Rays open issues
• How LHCf can contribute in this field
• Ov

Over ervie view of the LHCf e

• f the LHCf experiment

periment

• Forwar

ard pho d photon energy spectrum

• n energy spectrum

at at √s = 7eV pr s = 7eV proton-pr

• n-proton collisions

n collisions

• Summar

Summary and outlooks and outlooks

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

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 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 M.Haguenauer Ecole Polytechnique, France W.C.Turner LBNL, Berkeley, USA A-L.Perrot CERN, Switzerland

T h e L H C f c

• l

l a b

• r

a t i

• n

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

U H E C R O B S E R V A T I O N S ( 1 Y E A R S A G O A N D N O W )

Debate in AGASA, HiRes results in 10 years ago Now Auger, HiRes (final), TA indicate cutoff Absolute values differ between experiments and between methods

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

E S T I M A T E O F P A R T I C L E T Y P E ( X

M A X

)

Xmax

max giv

gives inf es informa rmation ion of the primar

• f the primary par

y partic icle le Results are dif esults are different erent be betw tween e een experiments periments Int Interpre reta tati tion relies on

• n relies on the MC predicti

the MC prediction and

• n and

has q has quit ite str e strong model dependence ng model dependence 0g/cm2 Xmax

Proton and nuclear showers

• f same total energy

Auger TA HiRes

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

LHC SPS AUGER

Cosmic ray spectrum

7T 7TeV+7T eV+7TeV eV

→ Elab

lab = 1

= 1017

17eV

eV 3.5T .5TeV+3.5T V+3.5TeV eV

→ Elab

lab = 2.6x1

= 2.6x1016

16eV

eV 450GeV+450GeV 450GeV+450GeV

→ Elab

lab = 2x1

= 2x1014

14eV

eV LHC giv LHC gives us s us the uniq the unique ue oppor

• pportunity t

unity to measure hadr measure hadronic

• nic int

interactions at 1 ractions at 1017

17eV

eV Tevatron

Ke Key p parameters for air r air sho shower de er developments lopments H O W L H CC A N C O N T R I B U T E ?

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

Total tal cr cross section

• ss section

↔ TOT

TOTEM, A ATLAS(ALFA) Multiplicity Multiplicity

↔ Central det

Central detect ctor

• rs

In Inelasticity/Secondar elasticity/Secondary spec spectra tra

↔ Fo

Forward c calorimete ters

LHCf LHCf, ZDCs

, ZDCs

η ∞

8.5

W H A T L H C FC A N M E A S U R E ?

Energy spectra and T Energy spectra and Transv ansver erse momentum se momentum distribution of distribution of

• Gamma

Gamma-ra

• rays (E>1

s (E>100GeV 00GeV,dE/E<5%) ,dE/E<5%)

• Neutral

Neutral Hadr Hadrons (E>a f

• ns (E>a few

w 100 00 GeV GeV, dE/E~30%) dE/E~30%)

• π0 (E>600GeV

(E>600GeV, dE/E<3%) , dE/E<3%) in the pseudo-rapidity range in the pseudo-rapidity range η>8.4 >8.4 Front view of calorimeters @ 100µrad crossing angle

Projected edge of beam pipe

Forward region is very effective

• n air shower development.

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

High energy flux !! High energy flux !! Lo Low multiplicity !! w multiplicity !!

Energy Flux @1 Energy Flux @14T 4TeV eV Multiplicity@1 Multiplicity@14T 4TeV eV

DPMJET3

Π0S P E C T R U M A N D A I R S H O W E R

Ar Artif tificial modification of meson cial modification of meson spectra (in agreement with dif spectra (in agreement with differences erences betw between models) and its ef een models) and its effect t ct to air air sho shower er Im Impor portance of E/E ance of E/E0>0. >0.1 mesons mesons

π0 spectrum at E spectrum at Elab

lab = 1

= 1019

19eV

eV QGSJET II original QGSJET II original Ar Artificial modif tificial modification cation Longitudinal AS de Longitudinal AS development lopment Ignoring X>0. Ignoring X>0.1 1 meson meson X=E/E X=E/E0

30g 30g/cm2

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

De Detect ctor

• rs insta

nstalled lled in the he TAN region, egion, 140 m away fr from

• m ATLAS

LAS Int nteract eraction ion Point

• int (IP1)

IP1)

Charged particles Neutral particles Beam pipe Protons

L H C FE X P E R I M E N T A L S E T

• U

P

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

Here the beam pipe splits in 2 separate tubes. Charged particle are swept away by magnets We will cover |η|>8

Front Counters: thin scintillators with 8x8cm2 acceptance installed in front of each main detector

A R M 1 & A R M 2 D E T E C T O R S

Arm# 1 Arm# 1

Arm# 2

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

16 scintillator layers (3 mm thick) Trigger and energy profile measurements Energy Impact point (η) 4 pairs of scintillating fiber

layers for tracking purpose (6, 10, 32, 38 r.l.) 4 pairs of silicon microstrip layers (6, 12, 30, 42 r.l.) for tracking purpose (X and Y directions)

Absorber

22 tungsten layers 7– 14 mm thick (2-4 r.l.) (W: X0 = 3.5mm, RM = 9mm) Expected Performance Energy resolution (> 100GeV) < 5% for g, 30% for neutrons Position resolution < 200µm (Arm#1), 40µm (Arm#2)

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

A T L A S & L H C F

Π0R E C O N S T R U C T I O N

Reconstruct constructed mass @ Arm2 d mass @ Arm2 measured energy spectrum @ Arm2 measured energy spectrum @ Arm2 preliminary An example of π0 events

• Pi0’

s are the main source of electromagnetic secondaries in high energy collisions.

• The mass peak is very useful to confirm the

detector performances and to estimate the systematic error of energy scale.

25mm 32mm

Silicon strip-X view m 140 =

R

θ

I.P I.P.1

θ γ1(E (E1)

γ2(E (E2) 140m 40m

R

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

P A P E R S U B M I T T E D T O P L B “ M E A S U R E M E N T O F Z E R O D E G R E E S I N G L E P H O T O N E N E R G Y S P E C T R A F O R √ S = 7 T E V P R O T O N - P R O T O N C O L L I S I O N S A T L H C “ A R X I V : 1 1 0 4 . 5 2 9 4 C E R N - P H - E P - 2 0 1 1 - 0 6 1 ,

L H C FO P E R A T I O N S @ 9 G E V& 7 T E V

With Stable Beam at 900 GeV Dec 6th – Dec 15th 2009 With Stable Beam at 900 GeV May 2nd – May 27th 2010 With Stable Beam at 7 TeV March 30th - July 19th 2010 We took data with and without 100 µrad crossing angle for different vertical detector positions

Shower Gamma Hadron Arm1 172,263,255 56,846,874 111,971,115 344,526 Arm2 160,587,306 52,993,810 104,381,748 676,157 Shower Gamma Hadron Arm1 46,800 4,100 11,527 Arm2 66,700 6,158 26,094

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

D A T A S E T F O R I N C L U S I V E P H O T O N S P E C T R U M A N A L Y S I S

• Data

Data

–Date : 15 May 2010 17:45-21:23 (Fill Number : 1104) except runs during the luminosity scan. –Luminosity : (6.5-6.3)x1028cm-2s-1, –DAQ Live Time : 85.7% for Arm1, 67.0% for Arm2 –Integrated Luminosity : 0.68 nb-1 for Arm1, 0.53nb-1 for Arm2 –Number of triggers : 2,916,496 events for Arm1 3,072,691 events for Arm2 –Detectors in nominal positions and Normal Gain

• Mont

Monte Carlo e Carlo

–QGSJET II-03, DPMJET 3.04, SYBILL 2.1, EPOS 1.99 and PYTHIA8.145: about 107 pp inelastic collisions each

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

Analysis Pr Analysis Procedure

• cedure
• 1. Energy Reconstruction from total energy deposition

in a tower (corrections for shower leakage, light yield etc.)

• 2. Particle Identification by analysis of the longitudinal shower

development

• 3. Remove multi-particle events by looking at transverse

energy deposit

• 4. Two Pseudo-rapidity regions selections, η>10.94

and 8.81<η<8.9

• 5. Combine spectra between the two detectors
• 6. Compare data with the expectations from the models

A N A L Y S I S F O R T H E P H O T O N S P E C T R A

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

En Energy rec ergy reconstruction nstruction : : Epho

photon = f(

= f(Σ(dE (dEi)) )) (i=2,3,…,

(i=2,3,…,13)

( dE ( dEi = A = AQi de

determin rmined at SPS. ed at SPS. f() f() de determin rmined b ed by MC. MC. E : EM eq E : EM equiv uivalent lent energy) energy) Im Impact position fr pact position from lat

• m lateral distribution

ral distribution Position dependent corrections sition dependent corrections

– Light collection non-uniformity – Shower leakage-out – Shower leakage-in (in case of two towers event)

Light collection nonunif Light collection nonuniformit rmity Sho Shower leak er leakage-out age-out Sho Shower leak er leakage-i age-in

A N A L Y S I S 1 .

• E

N E R G Y R E C O N S T R U C T I O N

• Energy

Energy scale can be scale can be check checked b d by π0 ident identifi ficati cation fr

• n from tw
• m two
• tower e

r events. ents.

• Mass shi

Mass shift obser

• bserved bo

ed both th in Arm1 (+7 in Arm1 (+7.8%) and Arm2 ) and Arm2 (+3.7% (+3.7%)

• No energy

No energy scalin scaling g applied, bu applied, but s t shif ifts assigned in the ts assigned in the sys systematic err ematic error in energy n energy

m 140 =

R

θ

I.P.1

θ γ1(E1)

γ2(E2) 140m R Arm2 Arm2 Measurement Measurement Arm2 MC Arm2 MC

M = θ√(E1xE2) A N A L Y S I S 1 .

• E

N E R G Y R E C O N S T R U C T I O N

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

• QGSJET2-gamma and -hadron are normalized to

data(/collision) independently

• LPM effects are switched on

A n a l y s i s 2 .

• P

a r t i c l e I d e n t i f i c a t i

• n

PID criteria based on transition curve

500 GeV 500 GeV <EREC

REC<1 T

<1 TeV

MC/Data comparison done in many energy bins

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

Double Double hit det hit detection ef ction efficiency ciency

Reject e ject events with multi-peaks ents with multi-peaks Identify multi-peaks in one tower by position sensitive layers. Select only the single peak events for spectra.

A N A L Y S I S 3 .

• M

U L T I

• H

I T I D E N T I F I C A T I O N

Arm1 Arm2

Small tower Large tower

Single hit Single hit det detection ction efficiency ciency

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

A N A L Y S I S 4 .

• A

C C E P T A N C E C U T

R1 = 5mm R2-1 = 35mm R2-2 = 42mm θ = 20o For Small Tower η > 10.94 For Large Tower 8.81 < η < 8.99 We define in each tower a region common both to Arm1 and Arm2, to compare the Arm1 and Arm2 reconstructed spectra. Our final results will be two spectra, one for each acceptance region,

• btained by properly weighting the Arm1 and Arm2 spectra

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

A N A L Y S I S 5 . ‒ C O M P A R I S O N O F A R M 1 A N D A R M 2 S P E C T R A

Multi-hit rejection and PID correction applied Energy scale systematic not considered due to strong correlation between Arm1 and Arm2 De Deviation in viation in small t small tower: r: still unclear still unclear, but but within within syst systematic err ematic errors

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

A N A L Y S I S 6 . ‒ C O M B I N A T I O N O F A R M 1 A N D A R M 2 S P E C T R A

Gra Gray hatch : hatch : Syst Systema ematic ic Err Errors Erro ror b bars : : statistical E Erro ror

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

Beam-Gas back Beam-Gas backgr grounds

• unds

B A C K G R O U N D S

1. 1. Pileup of collisions Pileup of collisions in in one beam

• ne beam cr

crossing

• ssing

Low Luminosity fill, L=6x1028cm-2s-1

• 7% pileup at collisions, 0.2% at the detectors.

2. 2. Collisions be Collisions betw tween secondar een secondary's and y's and beam pipes beam pipes

Very low energy particles reach the detector (few % at 100GeV)

3. 3. Collisions be Collisions betw tween beams and een beams and residual gas residual gas

Estimated from data with non-crossing bunches.

• <0.1%

Seco Secondar ndary-beam p beam pipe back pe backgr grounds

• unds

S Y S T E M A T I C U N C E R T A I N T I E S

Uncorrelated uncertainties between ARM1 and ARM2

• Energy scale (except π0 error)
• Beam center position
• PID
• Multi-hit selection

Correlated uncertainty

• Energy scale (π0 error)
• Luminosity error

Estimated for Arm1 and Arm2 by same methods but independently Estimated by Arm2, and apply it to the both Arm

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

Please have a look to the paper for detailed explanations!

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

C O M P A R I S O N B E T W E E N M O D E L S

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

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

Gray hatch Gray hatch : : Sy System ematic ic Errors Errors Magenta Magenta hatch: MC hatch: MC Statist Statistical l errors errors

C O N C L U S I O N S

• LHCf Inclusive photon analysis has been completed
• Many detailed systematic checks were necessary!
• First comparison of various hadronic interaction models with experimental data in

the most challenging phase space region (8.81 < η < 8.99, η > 10.94)

• None of the models perfectly agree with data
• Large discrepancy especially in the high energy region with all models.
• Implications on UHECR Physics under study in strict connection with relevant

theoreticians and model developers

• Other analysis are in progress (hadrons, PT distributions, different η

coverage etc.)

• LHCf was removed from the tunnel on July 20, 2010
• We are upgrading the detectors to improve their radiation hardness (GSO

scintillators)

• Discussions are under way to come back in the TAN for the possible p-Pb

run in 2013 (LHCC, Alice, LHC, Atlas etc.) or at RHIC for lower energy p- ions runs

• We will anyway come back in LHC for the 14 TeV run with upgraded

detector!!!!

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

K E Y M E A S U R E M E N T S

E leading baryon Elasticity / inelasticity Forward spectra (Multiplicity) Cross section EM shower E0

K E Y P A R A M E T E R S F O R T H E D E V E L O P M E N T O F T H E S H O W E R S

Predictions of the hadronic interaction models most commonly used in the UHECR simulation

Big discrepancy in the high energy region !!!

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

Total cross section Multiplicity Inelasticity/Secondary particles

M O D E L U N C E R T A I N T Y A T L H C E N E R G Y

Very similar!? similar!? π0 energy at energy at √s = s = 7T 7TeV eV Forwar ard concentrati d concentration of x>0. n of x>0.1 1 π0

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

F R O N T C O U N T E R

Fixed scintillation counter L=CxRFC ; conversion coefficient calibrated during VdM scans

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

C A L O R I M E T E R S V I E W E D F R O M I P Geome Geometrical acceptance of rical acceptance of Arm1 Arm1 and and Arm2 Arm2 Cr Crossing angle operation enhances the acceptance

• ssing angle operation enhances the acceptance

η ∞

8.7

θ

[µrad]

310

η ∞

8.5 0 cr 0 crossing

• ssing angle

angle 100urad cr 00urad crossing

• ssing angle

angle

Projected edge

• f beam pipe

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

L U M I N O S I T Y E S T I M A T I O N

Luminosity for the analysis is calculated from Front Counter rates: The conversion factor CF is estimated from luminosity measured during Van der Meer scan

LVDM = nb frev I1I2 2πσ xσ y

VDM scan BCNWG paper

https://lpc‐afs.web.cern.ch/lpc‐ afs/tmp/note1_v4_lines.pdf

L = CF × RFC

Beam sizes σx and σy measured directly by LHCf

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

E S T I M A T I O N O F P I L E U P

P(N) = λN exp[−λ] N!

When the circulated bunch is 1x1, the probability of N collisions per Xing is

λ = L⋅ σ frev

The ratio of the pile up event is

Rpileup = P(N ≥ 2) P(N ≥1) = 1−(1+ λ)e−λ 1−e−λ

The maximum luminosity per bunch during runs used for the analysis is 2.3x1028cm-2s-1 So the probability of pile up is estimated to be 7.2% with σ of 71.5mb Taking into account the calorimeter acceptance (~0.03) only 0.2% of events have multi-hit due to pile-up. It does not affect our results

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

Ef Effect of 1mm shif ct of 1mm shift in the f t in the final spectrum nal spectrum Beam cent Beam center LHCf vs er LHCf vs BPMS BPMSW LHCf online hit-map monit LHCf online hit-map monitor

B E A M C E N T E R M E A S U R E M E N T

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

U N C E R T A I N T Y I N S T E P . 2

• Im

Imper perfect ection

• n in L

in L90%

90% di

distr stribution

• n

Template fitting A Template fitting B (Small tower, single & gamma-like) Ar Artificial modif tificial modification in cation in peak positi peak position

• n (<0.7 r

(<0.7 r.l.) l.) and width (<20%) and width (<20%) Origina Original me method thod ε/P fr /P from tw

• m two me
• methods

thods (ε/P) /P)B/ ( / (ε/P) /P)A

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

U N C E R T A I N T Y I N S T E P . 3 Fraction of multi-hit and action of multi-hit and ∆εmulti,

multi, data- data-MC

Ef Effect of multi-hit ‘cut’ : dif ct of multi-hit ‘cut’ : difference betw erence between Arm1 een Arm1 and Arm2 and Arm2

Single / (single+multi), Arm1 vs Single / (single+multi), Arm1 vs Arm2 Arm2 Ef Effect of ct of ∆εmult

multi i to single pho

single photon spectra

• n spectra

S P E C T R A L D E F O R M A T I O N

Suppression due t Suppression due to multi-hit cut at medium energy multi-hit cut at medium energy Ov Overestimat erestimate due t due to multi-hit det multi-hit detection inef ction inefficiency at ficiency at high energy high energy (mis-identify multi pho

(mis-identify multi photons as single)

• ns as single)

No correction applied, but No correction applied, but same bias included in same bias included in MC MC to be com be compared ared

TR TRUE UE MEASURED MEASURED TR TRUE UE/MEAS MEASUR URED ED True: photon energy spectrum at the entrance of calorimeter

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

S Y S T E M A T I C E R R O R F R O M E N E R G Y S C A L E

Two components:

• Relatively well known: Detector response, SPS => 3.5%
• Unknown: π0 mass => 7.8%, 3.8% for Arm1 and Arm2.

Please note:

• 3.5% is symmetric around measured energy
• 7.8% (3.8%) are asymmetric, because of the π0 mass shift
• No ‘hand made’ correction is applied up to now for safety

Total uncertainty is

• 9.8% / +1.8% for Arm1
• 6.6% / +2.2% for Arm2

Systematic Uncertainty on Spectra is estimated from difference between normal spectra and energy shifted spectra.

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

π0M A S S

Arm1 Data

Peak at 145.8 ± 0.1 MeV

• Disagreement in the peak position
• No ‘hand made correction’ is applied for safety
• Main source of systematic error see later

Arm2 Data Arm2 MC (QGSJET2)

Peak at 140.0 ± 0.1 MeV Peak at 135.0 ± 0.2 MeV 3.8 % shift

Many systematic checks have been done to understand the energy scale difference

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

7.8 % shift

π0M A S S V Sπ0E N E R G Y

Arm2 Data No strong energy dependence

• f reconstructed mass

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

η M A S S

Arm2 detector, all runs with zero crossing angle True η Mass: 547.9 MeV MC Reconstructed η Mass peak: 548.5 ± 1.0 MeV Data Reconstructed η Mass peak: 562.2 ± 1.8 MeV (2.6% shift)

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

E F F E C T O F M A S S S H I F T

Energy rescaling Energy rescaling NO NOT applied but included in energy applied but included in energy err error Min

inv =

= θ √(E (E1 x E x E2)

–(∆E/E)calib = 3.5% –∆θ/θ = 1% –(∆E/E)leak-in = 2% => ∆M/M = 4.2% ; not sufficient for Arm1 (+7.8%)

145.8MeV (Arm1 observed) 135MeV ±7.8% flat probability ±3.5% Gaussian probability Quadratic Quadratic sum of tw sum of two err

• errors

is giv is given as energy err n as energy error (t (to allo

• allow bo

w both 1 135MeV and 35MeV and

• bser
• bserved mass peak)

d mass peak)

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

Π0M A S S S H I F T I N S T U D Y

• Reanalys

analysis of SPS calibrati

• f SPS calibration data in

data in 200 2007 and 20 and 2010 (post (post LHC) <20 LHC) <200GeV

• Re

Reev evaluation o

• f s

systematic e erro rors

• Reevaluation

aluation of EM sho

• f EM shower usi

er using dif g differen erent MC t MC codes (EPICS, FL codes (EPICS, FLUKA UKA, GEANT4) , GEANT4)

• Cable att

Cable attenuati nuation recalibration(1-2% im

• n recalibration(1-2% impr

prove e e expect pected) ed)

• Re-che

heck all ck all 1-2% e 2% effects… cts…

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

S U M M A R Y O F S Y S T E M A T I C E R R O R S

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

1 4 T E V : N O T O N L Y H I G H E S T E N E R G Y , B U T E N E R G Y D E P E N D E N C E …

7 TeV 10 TeV 14 TeV (1017eV@lab.) SIBYLL 7 TeV 10 TeV 14 TeV QGSJET2 Secondary gamma‐ray spectra in p‐p collisions at different collision energies (normalized to the maximum energy) SIBYLL predicts perfect scaling while QGSJET2 predicts softening at higher energy Qualitatively consistent with Xmax prediction

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

L H C

• C

O S M I C ?

p-Pb p-Pb rele relevant t nt to CR CR ph physics? ysics? CR- CR-Air int ir interaction raction is no is not t p-p, p-p, but A but A1-A

• A2 (A1:p, He,…,F

(A1:p, He,…,Fe, e, A2:N,O) A2:N,O)

LHC Nitr LHC Nitrogen-Nitr

• gen-Nitrogen collisions

gen collisions

Top: energy flo p: energy flow at 1 at 140m fr 40m from IP

• m IP

Lef Left : : pho photon energy spectra at

• n energy spectra at 0

0 degree degree

To Total Neutr Neutron

• n

Pho Photon

• n

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011

C O M P A R I S O N O F E J 2 6 A N D G S O

• R

A D I A T I O N H A R D N E S S

• EJ260 (HIMAC* Carbon beam)

10% decrease of light yield after exposure of 100Gy

• GSO (HIMAC Carbon beam)

No decrease of light yield even after 7*10^5Gy exposure, BUT increase of light yield is confirmed

• The increase depend on irradiation

rate (~2.5%/[100Gy/hour])

*HIMAC : Heavy Ion Medical Accelerator in Chiba

O S C A R A D R I A N I P L H C 2 011 , P E R U G I A , J U N E 6 , 2 011