Forward particle
measurements at colliders
andair shower development
Takashi Sako
High Energy Cosmic Ray Research Division, ICRR
2018/4/20

ICRR seminar

1What I was doing before joining ICRR

Forward particle
measurements at colliders
andair shower development
What I am studying at ICRR

Takashi Sako
High Energy Cosmic Ray Research Division, ICRR
2

Outline• Air shower observation and hadron interaction• Forward particle measurements at collider• LHCf and RHICf experiments• Introduction to the LHCf experiment• Forward 𝜋0 and neutron results• √s dependence• RHICf• Model tuning to the LHCf result and impact on air
shower simulation• Summary and future3

High-energy cosmic ray observations

Space/balloon
observations
Air shower observations• High-energy particles from outer space,cosmic rays, are observed• Majority of CRs is fully ionized nuclei
including protons• 1020eV(=16J) CRs are observed• LHC can accelerate up to 7x1012eV
Where is the origin of CRs?
How are they accelerated?
• Very low flux at high energyEx) >1020eV 1 ptcl/1km2/century• Direct observation is not available=> Air shower technique45High-energy cosmic ray observations

Space/balloon
observations
Air shower observations• High-energy particles from outer space,cosmic rays, are observed• Majority of CRs is fully ionized nuclei
including protons• 1020eV(=16J) CRs are observed• LHC can accelerate up to 7x1012eV
Where is the origin of CRs?
How are they accelerated?
• Very low flux at high energyEx) >1020eV 1 ptcl/1km2/century• Direct observation is not available=> Air shower technique
6

Air shower technique• km2~1000km2 detection area isachieved using a sparse array of
the ground detectors• Identification of primary particle(nuclei, gamma, etc…) is possible
by measuring the difference in the
air shower development• We can (want to) extract• Energy• Direction• Type (mass number, 𝛾, e-, 𝜈)of the primary particles

Spread over 100m – few km=>
Analyses strongly rely on the MC
simulation of air shower
development, especially fundamental
hadronic interaction is essential 7<ln (mass number)>Model dependent mass interpretation
QGSJET1QGSJETIISIBYLL

EPOS(Kampert and Unger, Astropart. Phys., 2012)• Is difference between proton and Helium small? => Factor 4 in mass number!!
• Is the truth really between the existing models? => Nobody knows!!

Models must be tested by accelerator data

8

Hadronic interaction in air shower
protonneutronCR proton𝜋±𝜋0photon (𝛾)muonneutrino

AtmosphericnucleusElectromagnetic
cascadeSpread over 100m – few km• km2~1000km2 detection area isachieved using a sparse array of
the ground detectors• Identification of primary particle(nuclei, gamma, etc…) is possible
by measuring the difference in the
air shower development• We can (want to) extract• Energy• Direction• Typeof the primary particles=>
Analyses strongly rely on the MC
simulation of air shower
development, especially fundamental
hadronic interaction is essential 9

Hadronic interaction in air shower
protonneutron• km2~1000km2 detection area isachieved using a sparse array of
the ground detectors• Identification of primary particle(nuclei, gamma, etc…) is possible
by measuring the difference in the
air shower development

CR proton𝜋±𝜋0photon (𝛾)muonneutrino

AtmosphericnucleusElectromagnetic
cascade• We can (want to) extract• Energy
SUPER simplified view:• Direction
incident particle [E]• Type-> a leading baryon [kelaE]of the primary particles+ multi mesons [(1-Kela)E/Nmulti]

Spread over 100m – few km=>
Analyses strongly rely on the MC
simulation of air shower
development, especially fundamental
hadronic interaction is essential10

Cosmic-ray spectrum and collision energy（D’Enterria et al., APP, 35,98-113, 2011 ）End of galactic CR andtransition to extra-gal CR
Ankle
Knee: end of galactic proton CR(GZK) cutoff:
end of CR spectrum

LHC beam energy
Indirect observation through air shower

11Cosmic-ray spectrum and collision energy（D’Enterria et al., APP, 35,98-113, 2011 ）

RHIC

LHC

FCC
End of galactic CR andtransition to extra-gal CR
Ankle

Knee: end of galactic proton CR(GZK) cutoff:
end of CR spectrum

7x1012eV+7x1012eV1017eV + (at rest)
Indirect observation through air shower

17eV
Though the particle energy is 7x1012eV at LHC, the collision energy corresponds to ECR=1012Detectors @ Colliders
Central detector(ATLAS, CMS, ALICE, STAR, …)
Beam particle(black solid)
Neutralparticles
collision
Elastic scattering（black dashed）

DipoleBeam pipeü Main physics at colliders are achieved using the “Central detectors”
ü But…
13

Angular distribution at colliders
multiplicity and energy flux at LHC 14TeV collisions

pseudo-rapidity; η= -ln(tan(θ/2))

Multiplicity

𝜂=0 𝜂=1
𝜂>1𝜂<0(𝜃=45∘)

Energy Flux

All particles

neutralü Most of the particles are produced in the central region
ü Most of the energy flows into very forward = relevant to CR air shower• forward = soft interaction; theoretical difficulty
14• experimental difficultyAngular distribution at colliders
multiplicity and energy flux at LHC 14TeV collisions

Energy Flux

pseudo-rapidity; η= -ln(tan(θ/2))
Electron Profile
1017eV proton
shower|η|<1
1<|η|<3.5
3.5<|η|<5
5<|η|<6.6
6.6<|η|<8
η>8

7

10

0-1
106

|η|<1
1<|η|<3.5
3.5<|η|<5
5<|η|<6.6
6.6<|η|<8
η>82

NumberMuon Density
𝜂 in the 1st interaction

Density [1/m ]Muon Density

10-1

10-2

10-3

0-2

105

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0

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200

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2

Depth [g/cm ]

0-4
0

500

1000 1500 2000 2500 3000 3500 4000 4500 5000

Distance [m]Fig. 6.1: Fraction of the air shower development for one proton induced air shower at 1017 eV prim𝜃∼1mrad(CMS) in the initial inelastic p-air collienergy, which is determined𝜂=8by the =>hadronic
particle production
in different
regionsare
for produced
electrons inü Mostacceptanceof the particles
inlongitudinal
the central profile
region(left hand-side and muons in la
500
1000
1500atof
2000
3000
3500into
4000very
4500
5000
distribution
ground(righthand-side).
The
acceptanceis calculated
in thecenter-of-mass frame ofü Mostthe 2500
energyflows
forward= relevant
to CR
air shower
Distance[m] LHC detectors. The major part of the air show
collision, andshown=values
are related
totheoretical
typical• theforwardsoft interaction;difficulty
15
determined •by particle
productionin the forward region.
experimental
difficulty17

ne proton induced air shower at 10 eV primaryForward detectors @ Colliders
Central detector(ATLAS, CMS, ALICE, STAR, …)

Beam particle(black solid)
ZDC/LHCf/
RHICf

Neutralparticles

ZDC/LHCf/
RHICfcollision

Roman
Pot

Elastic scattering（black dashed） Forward detector(CASTOR, TOTEM T1, T2)

Roman Pot

(TOTEM RP, ATLAS ALFA,
pp2pp, UA7)

Zero Degree Calorimeter(ZDC@ATLAS/CMS/ALICE/STAR/PHENIX, LHCf, RHICf)

DipoleBeam pipe

Minimum bias counter(MBTS, LUCID, BBC)

ü CMS CASTOR and TOTEM T1/T2 cover most forward at CMS
ü TOTEM/ALFA roman pots are powerful for total cross section measurements
ü ZDC/LHCf/RHICf cover neutral particles at zero degree(zero degree measurement is possible only in p-p, but not in p-pbar)

16

Forward detectors @ Colliders
Central detector(ATLAS, CMS, ALICE, STAR, …)

Beam particle(black solid)
ZDC/LHCf/
RHICf

Neutralparticles

ZDC/LHCf/
RHICfcollision

Roman
Pot

Elastic scattering（black dashed） Forward detector(CASTOR, TOTEM T1, T2)

Roman Pot

(TOTEM RP, ATLAS ALFA,
pp2pp, UA7)

Zero Degree Calorimeter(ZDC@ATLAS/CMS/ALICE/STAR/PHENIX, LHCf, RHICf)

DipoleBeam pipe

Minimum bias counter(MBTS, LUCID, BBC)

ü CMS CASTOR and TOTEM T1/T2 cover most forward at CMS
ü TOTEM/ALFA roman pots are powerful for total cross section measurements
ü ZDC/LHCf/RHICf cover neutral particles at zero degree(zero degree measurement is possible only in p-p, but not in p-pbar)

17

The LHC forward experiment
LHCf Arm#1

ATLAS
140m

Two independent detectors at either sideof IP1 (Arm#1, Arm#2 )
Beam
96mm

Beam pipe
Charged particles (+)

Neutralparticles

LHCf Arm#2

Charged particles (-)ü All charged particles are swept by dipole magnet
ü Neutral particles (photons and neutrons) arrive at LHCfü η>8.4 (to infinity) is covered18

LHCf Detectors
ü Imaging sampling shower calorimeters
ü Two calorimeter towers in each of Arm1 and Arm2
ü Each tower has 44 r.l. (1.6𝜆) of Tungsten,16 sampling scintillator and 4 position
sensitive layers
ü Plastic scintillators => GSO scintillators, SciFi => GSO bars in Run2
LHCf Arm#1 Detector
20mmx20mm+40mmx40mm
4 XY SciFi+MAPMT

LHCf Arm#2 Detector
25mmx25mm+32mmx32mm
4 XY Silicon strip detectors

19

LHCf Detectors
ü Imaging sampling shower calorimeters
ü Two calorimeter towers in each of Arm1 and Arm2
ü Each tower has 44 r.l. of Tungsten,16 sampling scintillator and 4 position
sensitive layers
ü Plastic scintillators => GSO scintillators, SciFi => GSO bars in Run2
LHCf Arm#1 Detector
20mmx20mm+40mmx40mm
4 XY SciFi+MAPMTTechnique of CALETLHCf Arm#2 Detector
25mmx25mm+32mmx32mm
4 XY Silicon strip detectors

Technique of PAMELA

20

Detector
construction in
Japan and Italy• All of design, construction, calibration of the detectors, dataacquisition and analyses are led by the Nagoya U group290mm90mm

Largest and Smallest TeV gamma-ray detectors

23

Sampling calorimetern, gamma• Incident particles develop showers in Tungsten• Deposited energy is sampled by scintillators interleaved (3% for EM showers)• Four strip detector layers record lateral distribution of showers

Event example @ LHC
Longitudinal development
EnergyParticle ID

Lateral distribution

Silicon X

Silicon Y

Incident position
Nb. of incident

Event categories of LHCf
Responsible for air shower core (elasticity)

Leading baryon(neutron)

LHCf calorimeters

Single hadron
event

Multi meson production

π0

photonSingle photon
event

Responsible for air shower EM particles (inelasticity)

π0

photonPi-zero event(photon pair)26

measurede charge
rted to afficients
n at the26]. Thentillation
gy using
ction areto single
showeriency ofe energyt events,
d energy
condary.
dary hits

4. π0 event selection
The π 0 are then identified by their decay into two
photons, leading to the distinct peak in the invariant mass
distribution around the π 0 rest mass. The invariant mass ofthe two photons is calculated using the reconstructed
photon energies and incident positions. The π 0 events usedin the analysis of this paper are classified into two
categories: Type-I π 0 and Type-II π 0 events. A Type-I event
is defined as having a single photon in each of the twocalorimeters of Arm1 or Arm2 (the left panel of Fig. 1). A
Type-II event is defined as having two photons in the same
calorimeter (the right panel of Fig. 1). Note that Type-II
events were not used in the previous analyses [18,19] andthus are taken into account for the first time in this paper.
As detailed in Sec. V B, the phase spaces covered by Type-I
and Type-II events are complementary. In particular, theinclusion of Type-II events extends the pT upper limit foranalysis from 0.6 GeV in the previous analyses to 1.0 GeV.

Particle ID (PID)

Neutron event

Photon event

1.6 interaction lengths

44 r.l.

The LHCf Collaboration / Physics Letters B 780

𝑀(( = 𝜃 𝐸+ 𝐸,
PHYSICAL REVIEW D 86, 092001 (2012)

O. ADRIANI et al.
500

300

signal window can be estimated using the likelihood function [LBG ðy; pT ; m## Þ] characterized by the best-fit thirdorder Chebyshev polynomial function. For simplicity,
LBG ðy; pT ; m## Þ is shortened as LBG in the following
text. Thus the signal distribution with background subtracted is given by200^ l ;"u Þfðy;pT ÞBG ;fðy;pT ÞSig ¼ fðy;pT ÞSigþBG ! Rðy;pT ; m;"∫FIG. 1. Observation of π 0 decay by a LHCf detector. Left: -1
LHCf-Arm1
s=7TeV,
Ldt=2.53nb
Type-I π 0 event having one
photon entering
each calorimeter.
0
Right: Type-II π 400
event 9.0
having< y <two
9.2 photons entering one
calorimeter, here entering the small calorimeter.

032007-5

Events / (1 MeV)

wer peakove, then [44] toositions,
nts, two
unctions.
ted from
ving two
eter but
selected
e-photonh Arm1(4)^ "l ; "u Þ is the normalization for the backwhere Rðy; pT ; m;ground distribution and written as

100

0
80

100

120

140

160

180

Reconstructed m γ γ [MeV]

Invariantmass
photon pair
FIG. 4 (color
online).ofReconstructedinvariant mass distribution within the rapidity range from 9.0
to 9.2. Solid curve shows0
Peak@ 135MeV from 𝜋 decay events
the best-fit composite physics model to the invariant mass
distribution. Dashed curve indicates the background component.
Solid and dashed curves indicate the signal and background

Rmþ3"
^
u

Shower depth parameter

LBG dm##
m!3"
^
l
:
Rmþ6"
^
l
u
L
dm
þ
L
dm
BG
##
BG
##
^
mþ3"
^
m!6"
u
l
Fig. 1. L 90% distribution
in Arm1 forthe events with the reconstructed energy^ l ;"u Þ ¼ Rm!3"
Rðy;pT ; m;"^(Adriani et al., PLB, 2018)

between 1.1 and 1.2 TeV. The black points represent
the experimental data with(5)
statistical error bars. The red and blue colored lines correspond to the template dis27
tributions obtained from the MC simulation for photons and hadrons, respectively.
The black line represents the total of the template distributions. These distributions
D. Unfolding of spectra
were normalized by the results of the template fitting. (For interpretation of the(Adriani et al., PRD, 2012)

ima
high
pho
betw
mak
Abo
hit
cros
1. ‘M
T
s
a
t
fa
it
d
2. ‘M
A
t
d
c
fa
t

Dynamic range and linearity test using UV pulse laser

ADC (0.025pC)

結果:各HVにおける光量とADC値の関係

部分反射フィルター

N2 laser（KEN-1020）• 337.1nm• 0.3ns pulse
Scintillators with 𝜏=9.6ns (EJ-260) and 𝜏=30ns(GSO) are used to avoid saturation

N2レーザー（KEN-1020,300psec）
波⻑:377nm

Laser intensity（MIP eq.）Non-uniformity calibration at HIMAC

Ø Calorimeters WITHOUT tungsten layers were scanned over the ion beam
Ø Signal intensity as a function of the position was extracted29

Detector performance @ CERN SPS

Y.Makino et al., JINST 12 P03023 (2017)
Resolution [µm]Data X

250

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Simulation
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χ 2 /DOF=0.90

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150Electronbeamenergy[GeV]
Electronbeamenergy[GeV](a)(b) 2040mm
mm 1st layer

Energy linearity
MC Y

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Data

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Electron beam energy [GeV]200(c) Electron
40100
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1st150layer [GeV]
energy30(a) Arm1: 20 mm tower.

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Simulation• Beam test using 100-250GeV electron and proton
beams• Charge to energy calibration factors• ∑dE to E function• Energy resolution, linearity, position resolutions
EventsEventsFigure 5. The energy deposit distributions of the experimental data (black points) and simulation (blue line)of the Arm1 40 mm tower which have the minimum-chi-square parameters set from the 2nd layer to the 10thlayer. Injected particles were 200 GeV electrons. The horizontal axis represents the ADC counts. The areaof each MC distribution is normalized to the area of the correspondent data distribution.

Events150
200
250Electron beam energy [GeV]

Figure 12. Energy dependence of the energy resolution of the Arm1 detector for data (filled circles) and MC
Data X(open circles, shifted horizontally by 5 GeV). The events in a250
4(8)theYcenter
8 mm ⇥ 4(8) mm square aroundDataof the 20(40) mm calorimeter tower were selected.
MC X

2017 JINST 12 P0302

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Figure 18. Position resolution of the GSO-bar hodoscope layers
1Installation into the LHC tunnel

LHCf/RHICf History
ü2004 LOI submitted to CERN
ü2006 TDR approved by CERN
ü2009 First data taking at √s=900GeV p-p collisionü2010 √s=7TeV p-p collisionü2013 √s=2.76TeV p-p & √sNN=5TeV p-Pb collisions
ü2015 √s=13TeV p-p collisionü2016 √sNN=8.1TeV p-Pb collisionü2017 √s=510GeV polarized p-p collision as RHICf
32

physics results

Publications

performance results

Photon(EM shower)

Neutron(hadronshower)Beam test

NIM, A671(2012) 129136

JINST, 9 (2014)
P03016

0.9TeV p-p

PLB, 715(2012) 298303

7TeV p-p

PLB, 703(2011) 128134

2.76TeV p-p

PRD, 86(2012) 092001
PRC, 89 (2014)065209

5.02TeV p-Pb
13TeV p-p

PLB, 750(2015) 360366

π0 (limited
acceptance)

PLB, 780(2018) 233239

π0 (full
acceptance)

Performance

IJMPA, 28(2013) 1330036
PRD, 94 (2016)
032007

Analysis in progress
33

physics results

Publications

performance results

Photon(EM shower)

Neutron(hadronshower)Beam test

NIM, A671(2012) 129136

JINST, 9 (2014)
P03016

0.9TeV p-p

PLB, 715(2012) 298303

7TeV p-p

PLB, 703(2011) 128134

2.76TeV p-p

PRD, 86(2012) 092001
PRC, 89 (2014)065209

5.02TeV p-Pb
13TeV p-p

PLB, 750(2015) 360366

π0 (limited
acceptance)

PLB, 780(2018) 233239

π0 (full
acceptance)

Performance

IJMPA, 28(2013) 1330036
PRD, 94 (2016)
032007

Analysis in progress34π0 pz spectra in 7TeV p-p collisions
10− 1
10− 2
10− 3

LHCf s=7TeV

10− 4

∫

-1

Ldt=2.64+2.85nb

10− 5

1

(d) 0.6 < p [GeV] < 0.8
Tpz [GeV]

10−1
10−2
10−3
−4

10

10−5
1000 2000
pz [GeV]

3000(b) 0.2 < p [GeV] < 0.4
T

1/σinel Ed3σ/dp3 [GeV-2]

T

1/σinel Ed3σ/dp3 [GeV-2](a) 0.0 < p [GeV] < 0.2

1

1/σinel Ed3σ/dp3 [GeV-2]

1/σinel Ed3σ/dp3 [GeV-2]

1/σinel Ed3σ/dp3 [GeV-2](PRD, 94 (2016) 032007)(e) 0.8 < p [GeV] < 1.0
Tpz [GeV]

11(c) 0.4 < p [GeV] < 0.6
Tpz [GeV]
LHCf (stat.+syst.)
DPMJET 3.06
QGSJET II-04
SIBYLL 2.1
PYTHIA 8.185
EPOS LHC

1000 2000
pz [GeV]3000

ü DPMJET3 and PYTHIA8 overestimate over all E-p range
ü EPOS-LHC and QGSJET II-04, standard in air shower MC, are not bad

T circles) in p + p collisions at ps = 7 TeV.
FIG. 5: (color online). Experimental combined pz spectra of the LHCf detector (filled
35
Shaded rectangles indicate the total statistical and systematic uncertainties. The predictions of hadronic interaction models
are shown for comparison (see text for details.)

0
𝜋 in 7TeV p-p collision

LHCf and models

36𝜋0 in 7TeV p-p collision

LHCf and models (ratio to data)
EPOS-LHC/LHCf data

PT

ratio

1GeV
2.0
1.5
0.5GeV

1.0
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0GeV

0

QGSJET II-04/LHCf data

1TeV

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SIBYLL 2.1/LHCf data

Pz

37

Neutrons in 7TeV p-p collision(√s=7TeV p-p；PLB 750 (2015) 360-366)

Zero degree(∼10% of other neutral hadrons at 140m are included both in data and MC)ü Only QGSJET II explains the characteristic peak near zero degree
ü DPM and PYTHIA under production at zero degree
ü DPM and PYTHIA not bad at off-zero degree. DPM is best.

38

6000
nergy [GeV]

Neutron, p-p √s=13TeV
Unfolded Spectra

0
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Ratio

1.5
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×10

−3

<< ηη< 8.99
< 8.998.81<8.81
η <8.81
8.99
×10
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LHCf p-p s = 13 TeV

QGSJET
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p-pII-04s = 13 TeV
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1.5

0.4

1

EPOS-LHCSIBYLL 2.3

0.8
dσn/dE [mb/GeV]dσn/dE [mb/GeV]

0.6

Ratio

Ratio

8.99 << ηη
< 9.22
8.99< 9.22

1.2

0.7

1
0.5

1000

2000

3000

4000

2000 0.2
4000

5000
6000
Energy [GeV]

6000

00

1000

2000 4000
2000

3000

4000

6000

5000
6000
Energy [GeV]

Energy [GeV]
Energy [GeV]
Energy [GeV]• In η > 10.76, data shows a strong increasing of neutron production in the0high energy region. This behavior is not2predicted by all models.
• EPOS-LHC and SIBYLL 2.3 have the best
agreement in 8.99 < η < 9.22,
1.5
8.81 < η < 8.99, respectively.
28-Feb.-2018

0.5
00

−3

Ratio

0.2

×10

dσn/dE [mb/GeV]

0.6

0.4

10.76
η >η<>10.76
8.99
η < 9.22

Ratio

0.8

Ratio

dσn/dE [mb/GeV]

1dσn/dE [mb/GeV]

1.2

−3

0.8

dσn/dE [mb/GeV]

×10

×10

−3

1 Meeting133rd LHCC

80.5

• High-energy
peak @
0 degreeis alsowith
the4000
13TeV5000data6000
00 confirmed
2000
3000
4000
5000
6000
1000
2000
3000
[GeV]
Energy [GeV]• NOTE: pT coverage isEnergy
different
from the 7TeV analysis
39

1000

√s scaling ; π0collision energy (in)dependence
ü Scaling is essential to extrapolate beyond LHC
ü (630GeV −) 2.76TeV – 7TeV
good scaling within uncertainties
ü Wider coverage in y and pT with 13TeV dataü Wider √s coverage with RHICf experiment in2017 at √s=510GeV

Feynman x;
xF = 2pz/√s40

√s scaling; Neutron @ zero degree
0.9

7%–22%

16%–39%

T

0.8

0.9

s =200 GeV : PHENIX gaussian p form
T

0.7

0.8

s =30.6 GeV : ISR

0.6

s =44.9 GeV : ISR

0.5

s =52.8 GeV : ISR

0.5
0.4
0.3

0.2

0.2

0.1

0.1

0

PHENIX: s = 200 GeV

0.6

s =62.7 GeV : ISR

0.4

LHCf: s = 7 TeV

0.7

0.3

section meat included in
nty was estifor the BBC
Gaussian pT
form1
s =200 GeV : PHENIX exponential p form

dσ/dx F[mb]ainties evalross section
included in
to be 9.7%
ion).
ured neutron
GeV for thethe simulaground fromulation. The
a was deterdiscussed inch collisiont.
d the beamsystematicwere calcuthe result of
cm, and theainty.

affected by the energy cutoff before the unfolding. The
pT range in each xF bin is 0 < pT < 0:11xF GeV=c from
Eq. (2) with the acceptance cut of r < 2 cm. The absolutenormalization uncertainty for the PHENIX measurement,
9.7%, is not included.

dσ /dx (mb)the energy

0

0.1

0.2

0.3

0.4

0.5

xF

0.6

0.7

0.8

0.9

1

0
0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

1
xF

PRD,
032006(2013)
LHCf, K.Kawade, PhD thesis, CERN-THESIS-2014-315
FIG. 13 PHENIX,(color online).
The88,
cross
section p
results
for forward
ﬃﬃﬃ
FigurepT range<thepTpublished< 0.11x
neutron production
in p þxp GeV/ccollisions at s ¼
200 GeV6.8:
are xF distribution
angle 0than
resultF GeV /cpT < 0.11
pT < 0.11ofxFneutrons
GeV/c atNarrowershown. Two different
forms, Fexponential (squares)
andGaussiantocomparewiththeprevious
works
at LHCfand ISR (PHENIX)
systematic uncertainties of the LHCf
√sused= 30-60@ISRStatistical√s = 7000[25].
GeV The@LHC
distribution.
uncertain(circles), were
for the pTGeV
shown as hatched area.
ties are shown as error bars for each point, areand systematic
√s
=
200
GeV
@RHIC
uncertainties are shown as brackets. The integrated pT region
for each bin is 0 < pT < 0:11xF GeV=c. Shapes of ISR results
form
the unfolded experimental spectra and given as below,
are also shown. Absolute normalization errors for
the PHENIX
and ISR are 9.7% and 20%, respectively.

032006-10

ü Excellent scaling at √s = 30-200GeV
dN (∆η∆E) 12π
ü √s = 7TeV result agrees in a peak
but slightly
dσstructure,× soft??
[mb],
(6.1)
n /dE =dE
L dφ
ü LHCf data at 900GeV, 2.76TeV, 13TeV to be analyzed
where dN (∆η∆E) means the number of neutrons observed in 41
the each raü RHICf data at 510GeV
becomesavailable
pidity range and each energy binning, L is the integrated luminosity corresponding to the data set. The last term is correction of the azimuthal√s scaling, or breaking?
LHCf 2.76TeV and 7TeV data shows√s scaling of forward 𝜋0
PHYSICAL REVIEW D 88, 032006 (2013)

A. ADARE et al.
TABLE I. The expected pT for r < 2 cm, mean pT value withthe experimental cut, and the efficiency for the experimental cut
estimated by the simulation (Fig. 12). The errors were derived
considering the uncertainty in the parameter aðxF Þ in theGaussian form evaluated by HERA.

RHICf

Mean pT (GeV=c)

Efficiency

0.072
0.085
0.096
0.104

0:779 # 0:014ð1:8%Þ
0:750 # 0:009ð1:2%Þ
0:723 # 0:006ð0:8%Þ
0:680 # 0:016ð2:3%Þ

are the efficiency for the experimental cuts and are listed inTable I. The errors were derived considering theuncertainty in the parameter aðxF Þ in the Gaussian form
evaluated by HERA. There is no significant difference inthe result in case of using the ISR (exponential) pT
distribution.
The mean values of the simulated pT distributions ineach energy region are also listed in Table I. The crosssection was obtained after the correction of the energy
unfolding and the cut efficiency.
Table II summarizes all systematic uncertainties evaluated as the ratio of the variation to the final cross section
values. The absolute normalization error is not included inthese errors. It was estimated by BBC counts to be 9.7%
(22:9 # 2:2 mb for the BBC trigger cross section).
The background contamination in the measured neutronenergy with the ZDC energy from 20 to 140 GeV for theacceptance cut of r < 2 cm was estimated by the simulation with the PYTHIA event generator. The background fromprotons was estimated to be 2.4% in the simulation. The
systematic uncertainty in the experimental data was determined to be 1.5 times larger than this as discussed inSec. II B 3. Multiple particle detection in each collision
was estimated to be 7% with the r < 2 cm cut.
In the cross section analysis, we evaluated the beam
center shift described in Appendix A as a systematic
uncertainty. For the evaluation, cross sections were calculated in the different acceptances according to the result of
the beam center shift while requiring r < 2 cm, and thevariations were applied as a systematic uncertainty.

hxF i
0.53
0.68
0.83
0.93

Exponential pT form

Gaussian pT form

0:243 # 0:024 # 0:043
0:491 # 0:039 # 0:052
0:680 # 0:044 # 0:094
0:334 # 0:035 # 0:111

0:194 # 0:021 # 0:037
0:455 # 0:036 # 0:085
0:612 # 0:044 # 0:096
0:319 # 0:037 # 0:123

LHCf

B. Result

The differential cross section, d!=dxp
F ,ﬃﬃﬃ for forward
neutron production in p þ p collisions at s ¼ 200 GeV
was determined using two pT distributions: a Gaussianform, as used in HERA analysis, and an exponential
form, used for ISR data analysis. The results are listed inTable III and plotted in Fig. 13. We show the results for xF
above 0.45 since the data below 0.45 are significantly
affected by the energy cutoff before the unfolding. The
pT range in each xF bin is 0 < pT < 0:11xF GeV=c from
Eq. (2) with the acceptance cut of r < 2 cm. The absolutenormalization uncertainty for the PHENIX measurement,
9.7%, is not included.

1

0.9
s =200 GeV : PHENIX exponential p form

0.8

s =200 GeV : PHENIX gaussian p form

pT distribution
Beam center shift
Proton background
Multiple hit

3%–10%

7%–22%
3%–31%
3.6%
7%

0.8

T

dσ /dx (mb)0.7

s =30.6 GeV : ISR

0.6

s =44.9 GeV : ISR

0.5

s =52.8 GeV : ISR

0.6
0.5
0.4
0.3

0.3

0.2

0.2

0.1

0.1
0

PHENIX: s = 200 GeV

0.7

s =62.7 GeV : ISR

0.4

LHCf: s = 7 TeV

0
0
0

0.1

0.2

0.3

0.4

0.5

xF

0.6

0.7

0.8

0.9

1

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

1xF

6.8: x distribution
neutrons(7TeV)
at p rangedata
0 < p < 0.11x GeV /c
ISR (30-60GeV), PHENIXFigure(200GeV)and ofLHCf
at LHCf and ISR (PHENIX) [25]. The systematic uncertainties of the LHCf
are shown
hatched area. neutrons
indicate √s scaling brakingof asforward

Gaussian pT
form

Exponential pT
form

0.9

T

neutronTABLE II. Systematic uncertainties for the cross section measurement. The absolute normalization error is not included inthese errors. The absolute normalization uncertainty was estimated by BBC counts to be 9.7% (22:9 # 2:2 mb for the BBC
trigger cross section).

0𝜋dσ/dx F[mb]Neutron xF
0.45–0.60
0.60–0.75
0.75–0.90
0.90–1.00

TABLE III. The result of the differential cross section
pﬃﬃﬃ
d!=dxF ðmbÞ for neutron production in p þ p collisions at s ¼
200 GeV. The first uncertainty is statistical, after the unfolding,and the second is the systematic uncertainty. The absolutenormalization error, 9.7%, is not included.

FIG. 13 (color online). The cross section p
results
for forward
F
T
T
ﬃﬃﬃ
neutron production in p þ p collisions at s ¼ 200 GeV areshown. Two different forms, exponential (squares) and Gaussian(circles), were used for the pT distribution. Statistical uncertainties are shown as error bars for each point, and systematic
uncertainties are shown as brackets. The integrated pT region
form the unfolded experimental spectra and given as below,
for each bin is 0 < pT < 0:11xF GeV=c. Shapes of ISR results

F

42

RHICf is a kind of Zero degree calorimeters@STAR interaction point
RHICf detector
•
•
•
•
•

Former LHCf Arm1 detector used at LHC
Two compact sampling calorimeters
44 r.l. (1.7 hadron interaction lengths)<5% and 40% energy resolutions for EM andhadronic showers, respectively<0.2mm and <1mm position resolutions for
EM and hadronic showers, respectively(traditional) Zero
Degree Calorimeter
behind RHICf

43

Collision rates in RHICf week
TL center

TS centerTop

TS center• Higher 𝛽* (=8m) than usual RHIC operation• Radial polarization (usually vertical) to maximize the single-spin asymmetry in vertical44• Luminosity∼1031 cm-2s-1

Quick look（statistics）
RHICf DAQ rate
• Max rate was limited ~1kHz• High rate events were prescaled• Low rate events were enhancedwith special triggers• Prescale factors were optimized
from time to time
Total : 110M events
RHICf+STAR
RHICf (shower event)Total acquisition time
1659min = 27.7 hours

RHICf (High-energy EM trigger)
RHICf (Type-I 𝜋0 trigger)
45

Quick look（polarization & spectrum）
Though physics of polarized beam collision is not covered in this talk…

• Polarization angle is 0 in usual
RHIC operation (vertical pol)• Radial polarization (90°) was
required for RHICf operation• Stable radial pol and asymmetry
was observed by ZDC

Enhanced by special triggers• Energy spectrum of EM-likeshowers in a 30 minutes run• High-energy EM showers and 𝜋0
were selectively triggered tocompensate the limited DAQ speed.

∼250GeV46

Quick look（basic performance）
Hit maps of >200GeV hadron-likeevents at different detector positions=> Determination of “zero degree”

Invariant mass of photon pairs=> 135MeV peak by 𝜋0

Correction factors considering the final alignment
and RHIC energy range are in study.

47

Quick look（common run with STAR）

West

East

ZDC

Neutral particles

RHICf

ZDC

collision
Roman
Pot

• Hadron-like (deep penetrating) showers were selected• Anticorrelation between the RHICf raw (folded) energy and ZDC measured energy (inADC unit) is confirmed• (Anti)correlation only with West ZDC as expected => correct event matching 48

Modeltuning to the LHCf results
SIBYLL2.3c-Diffの光子スペクトル
Tuned SIBYLL2.3
η>10.94

8.81<η<8.99
1/Ninel dNγ /dEγ [GeV-1]

10−5

1/Ninel dNγ /dEγ [GeV-1]

10−5
s = 13 TeV, 0.191 nb-1

10−6

s = 13 TeV, 0.191 nb-1

10−6

η>10.94, ∆ φ=180°

10−7

Data LHCf-Arm1, arXiv:1703.07678
Data Nch=0, ATLAS-CONF-2017-075
Syst. + Stat. Unc. LHCf-Arm1

10−7

10−8

10

10−11

ch

Original SIBYLL2.3
EPOS-LHC

Data Nch=0, ATLAS-CONF-2017-075−9

10

Syst. + Stat. Unc. LHCf-Arm1
Syst. + Stat. Unc. Nch=0

10−10

Syst. + Stat. Unc. N =0

10−8

Data LHCf-Arm1, arXiv:1703.07678−98.81<η<8.99, ∆ φ=20°

EPOS-LHC Nch=0

SIBYLL2.3c

SIBYLL2.3c Nch=0

SIBYLL2.3

SIBYLL2.3 Nch=0

SIBYLL2.3c-Diff

SIBYLL2.3c-Diff Nch=0

2000

SIBYLL2.3
SIBYLL2.3c-Diff

EPOS-LHC1000

SIBYLL2.3c

3000

4000

10−10

EPOS-LHC Nch=0
SIBYLL2.3c Nch=0
SIBYLL2.3 Nch=0
SIBYLL2.3c-Diff Nch=0

5000

6000

Photon Energy [GeV]

10−11

1000

2000

3000

4000

5000

6000

Photon Energy [GeV]• LHCfphoton events are categorized in ‘diffractive’ andSIBYLL2.3c-Diffは連動実験の結果をよく再現できるようになった。
X‘non-diffractive’ using the ATLAS information• SIBYLL2.3c–diff tuned to LHCf diffractive photons
49

3c-DiffによるXの予測
equivalent cm. energymaxs (TeV)
Avg. depth of shower max. hXmax i (gcm 2 )100tune Credit
Effectofnewto air shower
to Felix Reihn
SIBYLL2.3c-DiffによるX の予測
max<Xmax>

Credit to Felix Reihn

Small but visible impact

Auger 2014
HiRes / MIA
Fly’s Eye

Sibyll 2.3c-diff2014/Sibyll
MIA 2.3cye
800

Proton700

600

Sibyll 2.3c-diffSibyll 2.3c

1016

1017

Iron

Epos-LHC
QGSjetII-04

Epos-LHC
QGSjetII-04

1018
1019
Primary energy E0 (eV)

1020

10 2

q = 676 ⇥ 10 3

Iron

Sibyll 2.3c-diffSibyll 2.3c

Epos-LHC
QGSjetII-04

hNµ (E0 )i/E0

N𝜇

X

Iron

p
Proton-proton equivalent cm. energy s (TeV)
10100

4 ⇥ 10 3
3 ⇥ 10 3
2 ⇥ 10 3
102

3

Sibyll2.3c-diffSignificant impact

Iron

ProtonEµ > 1 GeV 2240 g/cm2
1016

Epos-LHC

1017
1018
1019
Primary energy E0 (eV)

50

1020

Summary• Air shower analyses are influenced by the uncertainty of hadronicinteraction• Current and future colliders cover the collision energies
appropriate to the air shower observations• Dedicated forward measurements are important• LHCf and RHICf observed forward particle production from
ECR=1014eV to 1017eV• Current popular models have reasonable agreement with the LHCf
results and they are updating• Next keys are• Combined analyses with the central detector (LHCf-ATLAS, RHICf-STAR)• Collision energy (in)dependence of particle production (ISR-PHENIXRHICf-LHCf)• Light ion collisions like p-O, O-O at LHC• Feedback from the air shower observations

51

52

protonCR proton

neutron𝜋±𝜋0photon (𝛾)muonAtmosphericnucleusneutrino

Electromagnetic
cascadeSpread over 100m – few km• km2~1000km2 detection
area is achieved using asparse array of the grounddetectors• Identification of primaryparticle (nuclei, gamma,
etc…) is possible bymeasuring the difference inthe air shower development=>
Analyses strongly rely on theMC simulation of air shower
development, especiallyfundamental hadronicinteraction is essential53

粒⼦⽣成素過程と空気シャワー発達① Inelastic cross section④ 2ndary interactions
nucleon, p

If large s
rapid development
If small s
deep penetrating② Forward energy spectrum
If softershallow development
If harder
deep penetrating③ Inelasticity k= 1-plead/pbeam
If large k(π0s carry more energy)
rapid development
If small k( baryons carry more energy)
deep penetrating
54

num

num

simulations for proton- and iron-induced air showers toto a change
the data is shown in Fig. 13. The simulations have been
performed 1 using the three contemporary hadronic inter1
action models that were either tuned to recent LHC data
-0.3
-0.2
-0.1
0
0.1
0.2
0.3(QGSJetII-04-0.2[95,96],-0.1Epos-LHC
00.1[97,98])
or0.2
foundtru in0.3good
bias
rec
tru
rec
bias
deviation after correction log (N )-C -log (N )deviation after correction log (Nµ )-Cµ -log (Nµ )
10 ch
ch
10 ch
10
10
A single
agreement with these measurements(Sibyll2.1[81], see[99]). andIt isnotingthatthe energyof exemplarily
the first fordata
not describe
Fig. 4. The distribution of the deviations between the reconstructed (bias corrected)
trueworthshower sizes
in caseof charged
particles (left,
the interval

CR mass estimation from air showertru
6:6 < log10 ðN tru
ch Þ < 6:7) and of muons (right, exemplarily for the interval 5:7 < log10 ðN l Þ < 5:8), as well as the determined parametrization (curves). To increase the available
simulation statistics, a mixed composition is used.

PAO, PRD, 90, 122005 (2014)

9
8.5
8

KASCADE-Grande data (full efficiency)
0°-18°
c. 78000 events
isolines according to
response matrix for:
p
Fe

i

5%

9.22-9.36

102

8.80-8.94

7.5
8.38-8.52

7
6.5
6
5

0.01%

5%

7.96-8.10
intervals of true energy
in log (E/GeV):
10
7.54-7.68

7.12-7.26
5.5
6
6.5
7
reconstructed number of muons log (Nµrec)of the data plane with constant probability (from the inner13 to

103

0.01%

10%

ations as well as that of the properties of the experiment. Shown!
"recare some isolines representing the cells log10 ðN recch Þ; log10 ðN l Þ

7.5

10

number of showers

10chrec. number of charged particles log (Nrec)

KASCADE Grande, Astropart. Phys., 47 (2013) 54-66

10#4 , represent the smallest probability value just considered in
the response matrix after its conditioning. As can be seen, these outer isolines cover almost all measured data; hence, the minimal probability is not set too large.
4. Error propagation

1

10

Response (color contours) was calculated using
QGSJET II-02 + FLUKA 2002.4

the outermost isoline: 0:1; 0:05 and 10#4 probability density). For
reasons of clarity, only the results for two exemplary primaries areillustrated: protons and iron nuclei. The isolines, which correspondrecto the log10 ðNrec
ch Þ-log10 ðN l Þ combinations with a probability ofFig. 5. A comparison between the measured shower size distribution (greyrechistogram) and some isolines with log10 ðN recl Þ-log10 ðN ch Þ combinations of constantprobability according to the parametrizations (from the inner to the outermost line
10%, 5% and 0.01%). This is illustrated exemplarily for protons as well as iron nuclei,
FIG. 13.
and in case of six energy bins (labelled below each isoline set).

The determination of the elemental energy spectra will be subjected to influences of different error sources. They can roughly beclassified in four categories (cf. [17] for details):(i) Statistical uncertainties due to the limited measurement time:
Due to the limited exposure, the measured data sample will
suffer from unpreventable statistical uncertainties, which
Energy evolution of the first two central moments of the X max distributio
are expected to be Poisson distributed. These uncertainties
iron primaries will
[80,81,95–98].
be propagated through the applied unfolding algorithm
In order to parametrize the dependence
resolution of thee of themu
and are usually amplified thereby. The statistical uncertainexperiment on the true sizes, a possible bias in the charged particle
ties can be determined by means of a frequentist approach:mu
and muon number reconstruction must first max
be correctedby using
bias
bias
The measured two-dimensional shower size plane is considappropriate correction functions C ch and C l , respectively, deter122005-19
ered as probability distribution. Based on a random
55 generamined based on the simulations. The correction is typically in thetor, a couple of artificial data sets are generated, which areorder of less than 10%. The distributions of the remaining deviaunfolded individually. The spread of the solutions represents
tions between the reconstructed (and bias corrected) and true

ü Techniques to estimate mass from air shower observations• Knee to Ankle : N – N• Ankle to Cutoff : <X >, Nü Interpretations rely on the MC predictions with an assumed hadronicinteraction modelWhat is difficulty in hadronic interaction?
• Hard scattering (large Q2); Perturbative QCD
2->2 scattering of individual partons (quarks and gluons)• Parton-parton cross section• Parton distribution function (PDF)• Hadronization (fragmentation function)
are relatively well understood separately(Collins and Martin, 1984)• Soft scattering (small Q2); non-perturbative
exchange of group of partons（mesons, Reggeon, Pomeron）
difficult in first principle calculation of cross sections
even for the elastic scattering
phenomenological modeling is necessaryu Nature does not have a boarder between soft andhard…

• Nuclear effect；
not so simple like “Glauber effect”
collective effect in dense matter depends on the impact
parameter and issue of modeling

Models must be tested by accelerator data

56

Setup of SPS beam test
Detector(Arm#1 or Arm#2)

Silicon Tracker(ADAMO)

Calorimeter

Moving Table

Trigger Scintillator

Ø Calorimeters were exposed to the SPS electron (100-200GeV), proton(350GeV) and muon (150GeV) beams
Ø Calorimeters were scanned over the beams
Ø Impact points were measured using a silicon strip tracker

57

Channel to channel calibration
Beam test results vs. MC simulation

180GeV electron

Ø Charge => energy factors are determined by scaling the MC results
to the experimental data58

Cosmic-ray flux
End of galactic nuclear CR andtransition to extra-gal CR
Ankle
Knee: end ofgalactic proton CR

Cutoff:end of CR spectrum• Maximum energy up to 1020 eV (LHC beam energy is 7x1012 eV)• Structures in the energy spectrum suggest their origins• Knee @ 1015eV … end of the galactic protons ??
• Ankle @ 1018eV … transition from galactic to ex-galactic origins ??
59• Cutoff @ 1020eV … end of the ex-galactic origin ??

10− 1
10− 2
10− 3

LHCf s=7TeV

10− 4

∫

-1

Ldt=2.64+2.85nb

10− 5(d) 0.6 < p [GeV] < 0.8
Tpz [GeV]

10−1
10−2
10−3
−4

10

10−5
1000 2000
pz [GeV]

3000(b) 0.2 < p [GeV] < 0.4
T

1/σinel Ed3σ/dp3 [GeV-2]

T

1/σinel Ed3σ/dp3 [GeV-2](a) 0.0 < p [GeV] < 0.2

1

1

11

1/σinel Ed3σ/dp3 [GeV-2]

1/σinel Ed3σ/dp3 [GeV-2]

1/σinel Ed3σ/dp3 [GeV-2]

π0 SIBYLL 2.1(e) 0.8 < p [GeV] < 1.0
Tpz [GeV](c) 0.4 < p [GeV] < 0.6
Tpz [GeV]
LHCf (stat.+syst.)
DPMJET 3.06
QGSJET II-04
SIBYLL 2.1
PYTHIA 8.185
EPOS LHC

1000 2000
pz [GeV]3000

ü Underestimate in low p , overestimate in high p
ü Totally overestimate because of larger phase space in high ppFIG. 5: (color online). Experimental combined pz spectraof the LHCf detector (filled circles)T
T in p + p collisions at s = 7 TeV.
Shaded rectangles indicate the total statistical and systematic uncertainties. The predictions of hadronic interaction models
60T
are shown for comparison (see text for details.)

1
10− 1
10− 2
10− 3

LHCf s=7TeV

10− 4

∫

-1

Ldt=2.64+2.85nb

10− 5

1

(d) 0.6 < p [GeV] < 0.8
Tpz [GeV]

10−1
10−2
10−3
−4

10

10−5
1000 2000
pz [GeV]

3000

11(b) 0.2 < p [GeV] < 0.4
T

1/σinel Ed3σ/dp3 [GeV-2]

T

1/σinel Ed3σ/dp3 [GeV-2](a) 0.0 < p [GeV] < 0.2

1/σinel Ed3σ/dp3 [GeV-2]

1/σinel Ed3σ/dp3 [GeV-2]

1/σinel Ed3σ/dp3 [GeV-2]

π0 EPOS-LHC(e) 0.8 < p [GeV] < 1.0
Tpz [GeV](c) 0.4 < p [GeV] < 0.6
Tpz [GeV]
LHCf (stat.+syst.)
DPMJET 3.06
QGSJET II-04
SIBYLL 2.1
PYTHIA 8.185
EPOS LHC

1000 2000
pz [GeV]3000

ü Very good agreement at mid-energy (large cross section range)
ü Slightly overestimate in high energy (small cross section range)pFIG. 5: (color online). Experimental combined pz spectra of the LHCf detector (filled circles) in p + p collisions at s = 7 TeV.
Shaded rectangles indicate the total statistical and systematic uncertainties. The predictions of hadronic interaction models
61
are shown for comparison (see text for details.)

1
10− 1
10− 2
10− 3

LHCf s=7TeV

10− 4

∫

-1

Ldt=2.64+2.85nb

10− 5

1

(d) 0.6 < p [GeV] < 0.8
Tpz [GeV]

10−1
10−2
10−3
−4

10

10−5
1000 2000
pz [GeV]

3000

11(b) 0.2 < p [GeV] < 0.4
T

1/σinel Ed3σ/dp3 [GeV-2]

T

1/σinel Ed3σ/dp3 [GeV-2](a) 0.0 < p [GeV] < 0.2

1/σinel Ed3σ/dp3 [GeV-2]

1/σinel Ed3σ/dp3 [GeV-2]

1/σinel Ed3σ/dp3 [GeV-2]

π0 QGSJET II-04(c) 0.4 < p [GeV] < 0.6(e) 0.8 < p [GeV] < 1.0
Tpz [GeV]T

pz [GeV]
LHCf (stat.+syst.)
DPMJET 3.06
QGSJET II-04
SIBYLL 2.1
PYTHIA 8.185
EPOS LHC

1000 2000
pz [GeV]3000

ü Perfect in shape, slightly underestimate in higher pü Totally slightly underestimatepFIG. 5: (color online). Experimental combined pz spectra of the LHCf detector (filled circles) inT p + p collisions at s = 7 TeV.
Shaded rectangles indicate the total statistical and systematic uncertainties. The predictions of hadronic interaction models
62
are shown for comparison (see text for details.)

Neutron SIBYLL 2.1

ü Lowest neutron yield, especially at zero degree

63Neutron QGSJET II-03

ü Qualitatively nice agreement, only model, at zero degree
ü Lower yield at non-zero angle
64

Neutron EPOS 1.99

ü Generally low yield
65

Detector performance

Arm2
ΔE/E ≈ 40%
ΔE/E < 5%66

モデルのdiffraction事象の生成質量分布

Energy flowΔη
low-mass
ü Post-LHC models (EPOS-LHC and QGSJET II-04) well explain
high-mass0
theP π results, but notXfor neutrons
Δη

∆η

1

ü DPMJET3P explains
the neutron results, but recently it is not a
Rapidity gap
popular model in CR simulations6
1.4
16

14

12

10

8

6

4

2

0

10

10

X

dσSD/dlog (ξ )[mb/log (ξ )]X

dσSD/dlog (ξ )[mb/log (ξ )]18πMX : Diffractive質量,0X系統の不変質量。
LHCf
MX 2
ξ X = (DPM3) ! e−ΔηQGSsII-04
EPOS-LHC

X

0.8

10

3

4

10

2

X

P
P
ü LHCf
13 TeV data allows
to access smaller1.2rapidity
than 7TeV
1

0.6

EPOS-LHCQGSJET-II-04
SIBYLL2.3
PYTHIA8212-SS

NeutronPYTHIA8212-DL(data contains
all neutral
hadrons−8−7−6

at 140m while MC
logis only(ξ ) neutrons)
10

X

2

0

−8

−6

Low-mass

−4

非弾性度

−2

0
log (ξ )10X

pseudo-rapidity (η)
小大Diffractionの生成質量分布はモデルによって違う、特にlow-mass
Black solid circle : LHCf data (π , LHCf 2012)
Dotted lines : π energy flow distribution of each model
67
diffractionの取り扱い。
Thick horizontal line : Energy flow calculation after p cut
to be covered in 13TeV

rapidity (y)

0

0

T

X

low-mass diffraction事象の感度
∆η

16

14

12

10

8

6

4

2

0

4

EPOS-LHC

1.2

QGSJET-II-04−8て約100%の検出効率がある。

PYTHIA8212-SS

0.8

PYTHIA8212-DL

0.6
−8

−7

−6

log (ξ )10

X❖ ATLAS-LHCf連動実験によるこれまで測定例のないlow-mass

−6

−4

−2

Low-mass

0
log10(ξ )SD(pp -> pX)

3

SD w/ central-veto

10

1.0
0.8
0.6

X

10

QGSJET-II-04 p-p, s = 13 TeV

4diffraction事象の選別方法を確立。

X

X

dσSD/dlog (ξ )[mb/log (ξ )]diffraction (log10(ξx) < -6.0)に対し

SIBYLL2.3

1

?

2

0

1.4

10

X

10

X

6

❖ Central-veto は low-mass

Efficiency

dσSD/dlog (ξ )[mb/log (ξ )]

X

10

X

dσSD/dlog10(ξ )[mb/log (ξ )]

18

2

0.4

1

0.2

0

0.0

−8

−6

−4

−2

0
log10(ξ )
X

−8

−6

−4

−2

0
68 (ξ )
log
10
X

X

結果１：光子スペクトル
η>10.94

8.81<η<8.99

10−5

1/Ninel dNγ /dEγ [GeV-1]

1/Ninel dNγ /dEγ [GeV-1]

10−5
ATLAS-LHCf Preliminarys = 13 TeV, 0.191 nb

10−6

η>10.94, ∆ φ=180°

−7

10

−6

Syst. + Stat. Unc. LHCf-Arm1−7

連動実験の結果（Diff. only)

Data Nch=0, ATLAS-CONF-2017-075
Syst. + Stat. Unc. LHCf-Arm1

Syst. + Stat. Unc. N =0
ch

−9

10

EPOS-LHCQGSJET-II-04
SIBYLL2.3
PYTHIA8212DL

EPOS-LHC

EPOS-LHC Nch=0

QGSJET-II-04

QGSJET-II-04 Nch=0

SIBYLL2.3

SIBYLL2.3 Nch=0

PYTHIA8212DLPYTHIA8212DL Nch=0

−11

10

Data LHCf-Arm1, arXiv:1703.07678
Data Nch=0, ATLAS-CONF-2017-075

Syst. + Stat. Unc. Nch=010−10

8.81<η<8.99, ∆ φ=20°

10−8Data LHCf-Arm1, arXiv:1703.07678

10

s = 13 TeV, 0.191 nb-1

10

10−8

−9

ATLAS-LHCf Preliminary

LHCfのみの結果(Diff.+non-diff.) 10

-1

10−10

EPOS-LHC Nch=0
QGSJET-II-04 Nch=0
SIBYLL2.3 Nch=0
PYTHIA8212DL Nch=0

−11

1000

2000

3000

4000 5000 6000
Photon Energy [GeV]

10

1000

2000

3000

4000 5000 6000
Photon Energy [GeV]✦ Nch = 0 の光子スベクトルのデータとモデル予測の比較：‣

η > 10.94：EPOS-LHCはデータをよく再現した。

‣

8.81 < η < 8.99：PYTHIA8212DLはデータをよく再現した。

69

X

Diffractionの生成質量分布の改良
P1

P

X

MX : Diffractive mass, X系統の不変質量ΔηξX = (

Rapidity gap

P2

MX 2
) ! e−Δηs:陽子が失った運動量の比

dσ SD
α P (t )2 α P (0)−1= fP (ξ X ,t)σ (M X2 ) ∝ ξ 1−2
((M
)
X
X)
dξ X dt

P3

pomeron flux

pomeron cross-section

α P (t) = α P (0) + α P′ t = 1+ Δ + α ′t : Pomeron 軌道
∆η
16

14

12

10

8

6

4

2

0

2

X

SIBYLL2.3
SIBYLL2.3c
SIBYLL2.3c-Diff

1

10

4

1.5

0.5

−8

−7

SIBYLL2.3に実装した元のpomeron flux

EPOS-LHCQGSJET-II-04

10

X

dσSD/dlog (ξ )[mb/log (ξ )]

6

10

X

10

X

dσSD/dlog (ξ )[mb/log (ξ )]18

SIBYLL2.3の作者である−6

log (ξ )10

Felix Reihnは連動解析の結X果に基づいて、SIBYLL2.3c

2のdiffractionの生成質量分布
0

−8

−6

−4

−2

0
log10(ξ )X

を改良した。

70

XSIBYLL2.3c-Diffの光子スペクトル
Tuned SIBYLL2.3
η>10.94

8.81<η<8.99
10−5

1/Ninel dNγ /dEγ [GeV-1]

1/Ninel dNγ /dEγ [GeV-1]

10−5
s = 13 TeV, 0.191 nb-1

10−6

s = 13 TeV, 0.191 nb-1

10−6

η>10.94, ∆ φ=180°−7

10

Data LHCf-Arm1, arXiv:1703.07678
Data Nch=0, ATLAS-CONF-2017-075
Syst. + Stat. Unc. LHCf-Arm1

−7

10

10−8

10

10−11

ch

Original SIBYLL2.3
EPOS-LHC

Data Nch=0, ATLAS-CONF-2017-075

10−9

Syst. + Stat. Unc. LHCf-Arm1
Syst. + Stat. Unc. Nch=0−10

Syst. + Stat. Unc. N =0

10−8

Data LHCf-Arm1, arXiv:1703.07678

10−9

8.81<η<8.99, ∆ φ=20°

EPOS-LHC Nch=0

SIBYLL2.3c

SIBYLL2.3c Nch=0

SIBYLL2.3

SIBYLL2.3 Nch=0

SIBYLL2.3c-Diff

SIBYLL2.3c-Diff Nch=0

2000

SIBYLL2.3
SIBYLL2.3c-Diff

EPOS-LHC1000

SIBYLL2.3c

3000

4000

−10

10

EPOS-LHC Nch=0
SIBYLL2.3c Nch=0
SIBYLL2.3 Nch=0
SIBYLL2.3c-Diff Nch=0

5000

6000

Photon Energy [GeV]

10−11

1000

2000

3000

4000

5000

6000

Photon Energy [GeV]71
SIBYLL2.3c-Diffは連動実験の結果をよく再現できるようになった。

X