Recent Results from the LHCf experiment Gaku Mitsuka (Nagoya - - PowerPoint PPT Presentation

SLIDE 1

Recent Results from the LHCf experiment

Gaku Mitsuka (Nagoya University)

• n behalf of the LHCf Collaboration

17th International Seminar on High Energy Physics, QUARKS2012 Yaroslavl, Russia, 4-10 June, 2012

1

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Outline

• Introduction and Physics motivation
• Status of LHCf
• Photon event analyses
• Photon analyses at √s=900GeV and 7TeV
• π0 analysis at √s=7TeV
• Capability of p-Pb run in 2012
• Conclusions and Future prospects

Keywords:

• (Ultra high energy) Cosmic rays
• LHC
• Forward particle productions

Beam1 Beam2 Central Forward IP

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

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

Totally ~30 collaborators

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Energy spectra of high energy cosmic rays

Energy (eV)

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10

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• 1

sr GeV sec)

2

Flux (m

• 28

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• 13

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• 7

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• 4

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• 1

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2

10

4

10

• sec)

2

(1 particle/m Knee

• year)

2

(1 particle/m Ankle

• year)

2

(1 particle/km

• century)

2

(1 particle/km

LEAP - satellite Proton - satellite Yakustk - ground array Haverah Park - ground array Akeno - ground array AGASA - ground array Fly's Eye - air fluorescence HiRes1 mono - air fluorescence HiRes2 mono - air fluorescence HiRes Stereo - air fluorescence Auger - hybrid

0.9TeV 7TeV 14TeV

Direct Indirect Energy, Composition, & direction →Source of cosmic ray →Structure of the universe (goal)

Energy (eV)

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10

18

10

19

10

20

10

21

10 )

• 1

sec

• 1

sr

• 2

m

2

(eV

24

J(E)/10

3

E

• 1

10 1 10

Yakustk - ground array Haverah Park - ground array Akeno - ground array AGASA - ground array Fly's Eye - air fluorescence HiRes1 mono - air fluorescence HiRes2 mono - air fluorescence HiRes stereo - air fluorescence Auger - hybrid

400 500 600 700 800 10 14 10 15 10 16 10 17 10 18 10 19 10 20 Elab (eV) Xmax (g/cm

2)

Proton Iron DPMJET 2.5 neXus 2 QGSJET 01 SIBYLL 2.1 Fly´s Eye HiRes-MIA Yakutsk 1993 Yakutsk 2001 CASA-BLANCA HEGRA-AIROBICC SPASE-VULCAN DICE

Xmax

proton Fe

GZK cutofg ?

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• It is not possible to directly* measure

cosmic rays above 1014eV, but possible indirectly using the cascade shower of daughter particles, Extensive Air- Shower(EAS).

• Composition and energy of cosmic rays

afgect the generation of EAS.

• Then understanding of high-energy

cosmic ray owes to the indirect technique: comparison between the MC simulation of EAS and observation.

• Largest systematic uncertainty of indirect

measurement is caused by the finite understanding of the hadronic interaction of cosmic ray in atmosphere.

Altitude [km] Radius [km]

* direct measurement of cosmic ray <1014eV is done by balloon, satellite, and ISS.

γ p Fe

Indirect measurement of cosmic rays

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Hadronic interactions for CR physics

CERN-LHCC-2006-004, 2008 JINST 3 S08006.

0.01 0.1 1 0.01 0.1 1

dσ dX XF

ad-hoc A ad-hoc B

dσ 1

F inela

XF

1e+06 1e+07 1e+08 200 300 400 500 600 700 800 900 1000

Number of Electrons

Vertical Depth (g/cm ) Vertical shower

ad-hoc A ad-hoc B

2

Model uncertainty on Xmax

Xmax(A) Xmax(B)

What should be measured by LHCf ??

• 1. Energy spectra of γ, π0 and n
• 2. Transverse momentum (pT) spectra
• 3. ECMS (in)dependence of the spectra
• 4. Nuclear efgects

Underlying theories

• pQCD (but mainly for large pT)
• Gribov-Regge approach (soft QCD)

Underlying phenomenologies

• String fragmentation
• Beam remnants
• Difgraction dissociation
• Nuclear efgects

Many models exist for CR physics

• QGSJET (S. Ostapchenko)
• EPOS (K. Werner and T. Pierog)
• etc...

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Arm2

ATLAS / LHCf LHCb

CMS / TOTEM

ALICE 26.7km

140m

• Zero degree instrumentation slot at 140m

away from IP1(ATLAS).

• p-p collision at √s=14TeV corresponds to

Elab=1017eV.

• Detectors are located at the best position to

measure the large energy flow that strongly contributes the air-shower development. Arm1

The LHCf detectors

Arm1 Arm2

Scintillation fibers (Scifi) Silicon strip detector 1ch~1mm 1ch~160µm

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Status of the LHCf experiment

2004, 2006, and 2007

• Calibration at SPS

(NIM A 671 (2012) 129–136)

2010

• Physics program at 900GeV/7TeV

was completed

(Luminosity : JINST 7 T01003 (2012) 7TeV photon : Phys. Lett. B 703 128-134 (2011))

• Post-calibration at SPS

2009

• First data taking at 900GeV

2012

• Possibly p-Pb run ?

(CERN-LHCC-2011-015 ; LHCC-I-021)

2008

• First data taking at 900GeV (only FC)

2009, 2010

• Beam test of GSO scintillator at

HIMAC (JAPAN, Chiba)

(JINST 6 T0900 (2011))

2011, 2012(Jun.)

• Beam test of the LHCf Arm1 detector

with GSO scintillator at HIMAC (JAPAN, Chiba)

Physics program at CERN R&D for 14TeV run 組み立ての様子 2012(Aug.-Sep.)

• Beam test of the LHCf Arm1 detector

with GSO scintillator at CERN-SPS

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Status of the LHCf experiment

2004, 2006, and 2007

• Calibration at SPS

(NIM A 671 (2012) 129–136)

2010

• Physics program at 900GeV/7TeV

was completed

(Luminosity : JINST 7 T01003 (2012) 7TeV photon : Phys. Lett. B 703 128-134 (2011))

• Post-calibration at SPS

2009

• First data taking at 900GeV

2012

• Possibly p-Pb run ?

(CERN-LHCC-2011-015 ; LHCC-I-021)

2008

• First data taking at 900GeV (only FC)

2009, 2010

• Beam test of GSO scintillator at

HIMAC (JAPAN, Chiba)

(JINST 6 T0900 (2011))

2011, 2012(Jun.)

• Beam test of the LHCf Arm1 detector

with GSO scintillator at HIMAC (JAPAN, Chiba)

Physics program at CERN R&D for 14TeV run 組み立ての様子 2012(Aug.-Sep.)

• Beam test of the LHCf Arm1 detector

with GSO scintillator at CERN-SPS

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Photon event analysis

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Photon analysis at √s=900GeV

Arm1 data vs Arm2 data

Preliminary Preliminary

Arm1 Arm2

• Photon like events are categorized

into two pseudo-rapidity ranges:

• η>10.15
• 8.77<η<9.46
• Unavoidable PID ineffjciency and

impurity are corrected in each bin.

• Integral luminosity ~ 0.3nb-1,

and uncertainty is 21% (invisible).

• Independent data analyses show an
• verall good agreement within their

systematic uncertainties.

Beam pipe shadow Beam pipe shadow

Submitted to PLB.

Cross section of the LHCf detectors

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Photon analysis at √s=900GeV

Arm1 data vs Arm2 data

Preliminary Preliminary

Arm1 Arm2

• Photon like events are categorized

into two pseudo-rapidity ranges:

• η>10.15
• 8.77<η<9.46
• Unavoidable PID ineffjciency and

impurity are corrected in each bin.

• Integral luminosity ~ 0.3nb-1,

and uncertainty is 21% (invisible).

• Independent data analyses show an
• verall good agreement within their

systematic uncertainties.

Beam pipe shadow Beam pipe shadow

Submitted to PLB.

Cross section of the LHCf detectors

η = − ln  tan ✓θ 2 ◆

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SLIDE 14

Preliminary Preliminary

Arm1 Arm2 Beam pipe shadow Beam pipe shadow

Arm1 data vs Arm2 data

Photon analysis at √s=900GeV

Submitted to PLB.

• Photon like events are categorized

into two pseudo-rapidity ranges:

• η>10.15
• 8.77<η<9.46
• Unavoidable PID ineffjciency and

impurity are corrected in each bin.

• Integral luminosity ~ 0.3nb-1,

and uncertainty is 21% (invisible).

• Independent data analyses show an
• verall good agreement within their

systematic uncertainties. Cross section of the LHCf detectors

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Preliminary Preliminary

Arm1 Arm2 Beam pipe shadow Beam pipe shadow

Arm1 data vs Arm2 data

Photon analysis at √s=900GeV

Submitted to PLB.

• Photon like events are categorized

into two pseudo-rapidity ranges:

• η>10.15
• 8.77<η<9.46
• Unavoidable PID ineffjciency and

impurity are corrected in each bin.

• Integral luminosity ~ 0.3nb-1,

and uncertainty is 21% (invisible).

• Independent data analyses show an
• verall good agreement within their

systematic uncertainties. Cross section of the LHCf detectors

12

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Photon analysis at √s=900GeV

Preliminary Preliminary

Combined data (Arm1 and Arm2) vs MC simulations

• None of interaction models perfectly reproduce the LHCf data.
• EPOS and SIBYLL(x~2) show a reasonable agreement with the LHCf data.
• DPMJET, QGSJET and PYTHIA are in good agreement Eγ<200GeV, but

harder above 200GeV → ECMS dependent or independent ?

Submitted to PLB.

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Photon analysis at √s=7TeV

/GeV

ine

Events/N

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10

• 9

10

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• 4

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• 3

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• 1

Ldt=0.68+0.53nb

∫

Data 2010, Data 2010, Stat. + Syst. error DPMJET 3.04 QGSJET II-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145

=7TeV s LHCf Gamma-ray like

°

= 360 φ Δ > 10.94, η

/GeV

ine

Events/N

• 10

10

• 9

10

• 8

10

• 7

10

• 6

10

• 5

10

• 4

10

• 3

10

• 1

Ldt=0.68+0.53nb

∫

Data 2010, Data 2010, Stat. + Syst. error DPMJET 3.04 QGSJET II-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145

=7TeV s LHCf Gamma-ray like

°

= 20 φ Δ < 8.99, η 8.81 <

Energy[GeV] 500 1000 1500 2000 2500 3000 3500 MC/Data 0.5 1 1.5 2 2.5 Energy[GeV] 500 1000 1500 2000 2500 3000 3500 MC/Data 0.5 1 1.5 2 2.5

Combined data (Arm1 and Arm2) vs MC simulations

PLB 703 (2011) 128–134.

• Again, none of interaction models perfectly reproduce the LHCf data.
• EPOS has the smallest η (i.e. pT) dependence against the LHCf data.
• QGSJET and SIBYLL show the somewhat large dependent on η.
• Tendencies at 900GeV are mostly same as 7TeV except for QGSJET and SIBYLL.

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SLIDE 18

Scaling of the photon spectra

Arm1-Data Preliminary

• Good agreement of each XF scaling spectrum indicates a weak

dependence of <pT> on ECMS.

• Does this indicate the weak pT dependence of π0 ?

Data 2010 at √s=7TeV (η>10.94) Data 2010 at √s=900GeV Small tower : 22.6% Large tower : 77.4% Scaling factor : 0.1

Arm1-EPOS Preliminary

1 σinel dσγ dXF

• η<limited /

1 σinel dσγ pTdpTdXF hpTidpT

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Type-I Type-II

Energy [GeV] 500 1000 1500 2000 2500 3000 3500 [GeV/c]

T

P 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

• 8

10

• 7

10

• 6

10

Type-I sample

Energy [GeV] 500 1000 1500 2000 2500 3000 3500 [GeV/c]

T

P 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

• 9

10

• 8

10

Type-II sample

Type-II at small tower Type-II at large tower

Type-I LHCf-Arm1 Type-II LHCf-Arm1

LHCf-Arm1 Data 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=7TeV

IP

• 2
• 1

IP

• 1
• 2

Submitted to PRD (arXiv:1205.4578).

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Rapidity 9 9.5 10 10.5 11 [GeV/c]

T

p 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

• 5

10

• 4

10

• 3

10

• 2

10

E=1TeV E=2TeV E=3TeV

LHCf-Arm1

]

2

[MeV/c

γ γ

Reconstructed m 80 100 120 140 160 180 )

2

Events / (1 MeV/c 100 200 300 400 500

• 1

Ldt=2.53nb

∫

=7TeV, s LHCf-Arm1 9.0 < y < 9.2

Signal window : [-3σ, +3σ] Sideband : [-6σ, -3σ] and [+3σ, +6σ] Preliminary

Acceptance for π0 at LHCf-Arm1

[GeV]

T

P 0.1 0.2 0.3 0.4 0.5 0.6 Events / (0.02) 1 10

2

10

3

10

True spectra Measured spectra Unfolded spectra(by UE-EPOS) Unfolded spectra(by UE-PYTHIA)

=7TeV s LHCf-Arm1 9.0 < y < 11.0

Validity check of unfolding method

• Remaining background spectrum is estimated using

the sideband information, then the BG spectrum is subtracted from the spectrum made in the signal window.

• Raw distributions are

corrected for detector responses by an unfolding process that is based on the iterative Bayesian method.

(G. D’Agostini NIM A 362 (1995) 487)

• Detector response corrected

spectrum is proceeded to the acceptance correction.

LHCf-Arm1 √s=7TeV 9.0<y<11.0

True EPOS Unfolded(by π0+EPOS) Unfolded(by π0+PYTHIA) Measured EPOS

π0 analysis at √s=7TeV

f(y, pT)Sig = f(y, pT)Sig+BG − f(y, pT)BG R ˆ

m+3σu ˆ m−3σl LBGdm

R ˆ

m−3σl ˆ m−6σl LBGdm +

R ˆ

m+6σu ˆ m+3σu LBGdm

Submitted to PRD (arXiv:1205.4578).

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• LHCf data are mostly bracketed among hadronic interaction models.
• DPMJET, SIBYLL(x2) and PYTHIA are apparently harder, while QGSJET2 is softer.

π0 analysis at √s=7TeV

MC simulations vs Combined spectra (Arm1 and Arm2 data)

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

]

3

c

• 2

[GeV

3

/dp σ

3

Ed

inel

σ 1/

• 4

10

• 3

10

• 2

10

• 1

10 1

Data 2010 DPMJET 3.04 QGSJET II-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145

• 1

Ldt=2.53+1.90nb

∫

π =7TeV s LHCf 8.9 < y < 9.0

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

]

3

c

• 2

[GeV

3

/dp σ

3

Ed

inel

σ 1/

• 4

10

• 3

10

• 2

10

• 1

10 1

• 1

Ldt=2.53+1.90nb

∫

π =7TeV s LHCf 9.0 < y < 9.2

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

]

3

c

• 2

[GeV

3

/dp σ

3

Ed

inel

σ 1/

• 4

10

• 3

10

• 2

10

• 1

10 1

• 1

Ldt=2.53+1.90nb

∫

π =7TeV s LHCf 9.2 < y < 9.4

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

]

3

c

• 2

[GeV

3

/dp σ

3

Ed

inel

σ 1/

• 4

10

• 3

10

• 2

10

• 1

10 1

• 1

Ldt=2.53+1.90nb

∫

π =7TeV s LHCf 9.4 < y < 9.6

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

]

3

c

• 2

[GeV

3

/dp σ

3

Ed

inel

σ 1/

• 4

10

• 3

10

• 2

10

• 1

10 1

• 1

Ldt=2.53+1.90nb

∫

π =7TeV s LHCf 9.6 < y < 10.0

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

]

3

c

• 2

[GeV

3

/dp σ

3

Ed

inel

σ 1/

• 4

10

• 3

10

• 2

10

• 1

10 1

• 1

Ldt=2.53+1.90nb

∫

π =7TeV s LHCf 10.0 < y < 11.0

Submitted to PRD (arXiv:1205.4578).

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π0 analysis at √s=7TeV

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

π =7TeV s LHCf 8.9 < y < 9.0

• 1

Ldt=2.53+1.90nb

∫

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

MC/Data

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

π =7TeV s LHCf 9.0 < y < 9.2

• 1

Ldt=2.53+1.90nb

∫

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

MC/Data

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

π =7TeV s LHCf 9.2 < y < 9.4

• 1

Ldt=2.53+1.90nb

∫

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

MC/Data

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

π =7TeV s LHCf 9.4 < y < 9.6

• 1

Ldt=2.53+1.90nb

∫

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

MC/Data

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

π =7TeV s LHCf 9.6 < y < 10.0

• 1

Ldt=2.53+1.90nb

∫

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

MC/Data

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

π =7TeV s LHCf 10.0 < y < 11.0

• 1

Ldt=2.53+1.90nb

∫

[GeV/c]

T

p

0.1 0.2 0.3 0.4 0.5 0.6

MC/Data

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

MC simulations / Combined spectra (Arm1 and Arm2 data)

• Harder models use the Lund “popcorn” model → produce hard mesons.
• QGSJET allows only one quark exchange in collision → leading is always baryon.

Submitted to PRD (arXiv:1205.4578).

19

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π0 analysis at √s=7TeV

LHCf (this analysis) UA7

S) p QGSJET II-03 (Sp QGSJET II-03 (LHC) S) p SIBYLL 2.1 (Sp SIBYLL 2.1 (LHC) S) p EPOS 1.99 (Sp EPOS 1.99 (LHC)

lab

y

• 2
• 1.5
• 1
• 0.5

0.5 1 1.5 > [MeV/c]

T

<p 50 100 150 200 250 300 350 400

Data 2010 Best-fit function

[GeV/c]

T

p 0.1 0.2 0.3 0.4 0.5 0.6

3

/dp σ

3

Ed

inel

σ 1/

• 4

10

• 3

10

• 2

10

• 1

10 1

π =7TeV s LHCf 9.2 < y < 9.4

• 1

Ldt=2.53+1.91nb

∫

1 σinel E d3σ dp3 = A · exp(− q pT2c2 + m2

π0c4/T)

hpTi = r πmπ0c2T 2 K2(mπ0c2/T) K3/2(mπ0c2/T)

• 1. Thermodynamics

(Hagedron, Riv. Nuovo Cim. 6:10, 1 (1983))

hpTi = R ∞ 2πp2

Tf(pT)dpT

R ∞ 2πpTf(pT)dpT

• 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

→ this indicates the prediction at UHE region may difger from at the LHC energy region.

PLB 242 531 (1990)

ylab = ybeam - y Submitted to PRD (arXiv:1205.4578).

pT spectra vs best-fit function Average pT vs ylab

20

SLIDE 24

Nuclear efgects

Glauber theory

13 14 15 16 17 18 19 20 Cross section (proton−air) [mb] 200 300 400 500 600 700 800 QGSJET01c EPOS 1.61 SIBYLL 2.1 QGSJETII.3 Energy [eV]

13

10

14

10

15

10

16

10

17

10

18

10

19

10

20

10 [GeV]

pp

s Equivalent c.m. energy

3

10

4

10

5

10 Tevatron LHC

accelerator data (p−p) + Glauber

Atmosphere = Nitrogen & Oxygen (!=proton)

Ulrich et al, PRD 83, 054026

b

Saturation efgects

Used in many hadronic interaction models Non-linear parton density Multi-pomeron interactions Color glass condensate

Low-E High-E

• LHC plans to operate p-Pb collisions in

November 2012.

• This collision scheme is much closer to the

situation of cosmic ray (p or Fe) - atmosphere (N and O) interaction than p-p collisions.

CERN-LHCC-2011-015

21

SLIDE 25

Conclusions and Future prospects

• LHCf has measured the energy and transverse

momentum spectrum of the forward emitted particles at the 900GeV and 7TeV proton-proton collisions.

• Feynman scaling spectrum of the 900GeV and 7TeV

photon events agree well each other. This may indicate a weak dependence of PT on ECMS.

• Consistent π0 spectra are obtained between the Arm1

and Arm2 detector. Combined spectra agree with the prediction by EPOS for the pT spectra and <pT>.

• Many analyses are ongoing:
• Neutron analysis → energy flow of EAS
• Extends to other meson/baryon (e.g. η, K0, Λ)

22