Rauf Mukhamedshin

1
On problems of choice of hadron interaction
models and study of PCR spectrum at ultra high
energies

• Rauf Mukhamedshin
• Institute for Nuclear Research
• Moscow Russia

2

Introduction

• Traditional ground-based EAS arrays detect
  lateral distributions of secondary particles (e?
  or m?)
• The higher EAS E0, the larger distance of
  operated detectors from the EAS axis
• Lateral distributions depend on E0, ltptgt,
  observation depth etc.
• The larger is ltptgt, the higher could be the
  estimated EAS energy

r (r)
larger ltptgt
lower ltptgt
r
3

Introduction
QGS models (QGSJETs, SYBILLs, HDPM, DPMJET,
VENUS) present the most popular concept BUT! Can
these models describe all hadron interaction
features at E0?1016 eV? NO! Phenomenon of
alignment (or coplanarity) of most energetic
cores in g-h families observed with XRECs is
beyond QGSM
4

X-ray Emulsion Chambers (XREC)
XRECs aboard balloons and airplanes
Ethr gt 4 TeV
XRECs of PAMIR experiment
Carbon C-XREC
Lead Pb-XREC
5

• 
  

XREC Experimental data
cikRik (EiEk)1/2 2Zik
Energetically Distinguished Cores (EDC)
isolated clusters of particles (g,e?,h) joined
with decascading
p
p
procedure merging of close (Ziklt ZC) i-th and
k-th particles for reconstruction of
initial g-rays Z? 1
TeVcm p0-mesons Z? 3 TeVcm hadrons
Z? 20 TeVcm
X-ray films
g
p0
h
6

Experimental data on alignment
Examples of aligned events
a)
b)
5 most energetic particles
e)
g-ray clusters
c)
d)
? Pt ? 23 ? 7 GeV/c (Preliminary !)
Electromagnetic halo
hadron halo
hadron
g-ray cluster
Pamir a) Four- g-cluster event b) Pb-6
l40.95 c) Pb-28 l40.85. d) JF2af2 event
(Concorde) e) Strana event (balloon).
Digitals mean energy in TeV
j
-1/(N-1) lN 1.0 Aligned event lN lfix
Usually l4 0.8
k
jkij
i
7
Mini-Andromeda III

• Experimental data on alignment

upper chamber
lower chamber
Ehalo 4,400 TeV
S.Yamashita JPSJ(1985)529
8

Experimental data on alignment
Fraction of aligned families

• Pamir Experiment (SEg 700 TeV, l4 0.8)
• 0.43?0.13 in Pb-XREC (6 from 14, 1.0 expected)
• 0.27?0.09 in ?- XREC (9 from 35, 2.1 expected)
  
• Expected background 0.06

• Kanbala data (SEg 500 TeV, l3 0.8)
• 0.5?0.2 in Fe-XREC (3 from 6, 1.2 expected)
• Expected background 0.21

Xue L. et al. 1999

• Only two stratospheric g-h families (SEg ? 1000
  TeV). Both are extremely aligned
• l4 (g) 0.998 (JF2af2, Concorde)
• l4 (h) 0.99 (Strana, balloon)

Regress.coeff. b38(g) 0.992
Fluctuations ?
Magnetic field ?
Thunderstorm electric field ?
Strong interactions ?
9

Simulation

• Code MC0

• QGSM-type model
• describes PAMIR Collaborations data at ltE0gt ?
  51015 eV (vs ? 3 TeV) and a lot of
  accelerator data
• close to QGSJET 98 (CORSIKA) in features and
  simulation results

• Alignment and fluctuations

Binomial distribution
Probability to observe k aligned events in a set
of n events

_____________ s ?npq
10

• Alignment and fluctuations

Experiment Criterion Expected aligned-event number (probability for 1 event) Experi-mental event number Expected standard deviation (s) Deviation from expected event number (in s) Probability to observe experim. data
Pamir (Pb) l40.8 1.0 from 14 6 1.0 5 0.9?10-4
Pamir (?) l40.8 2.1 from 35 9 1.5 4,6 1.5?10-4
Kanbala l30.8 1.2 from 6 3 1.2 1.5 900?10-4
Strana l40.99 0.0029?0.0002 1 0.05 - 29?10-4
JF2af2 l40.998 0.0006?0.0001 1 0.015 - 6?10-4
Probability to observe the total set of
experimental aligned events (Pamir, Kanbala,
stratosphere) Wfluct 0.9 ?10-4 ? 1.5 ?10-4 ?
9 ?10-2 ? 3?10-3 ? 6 ?10-4 lt 10 14 It is
an upper limit only !
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• Alignment and fluctuations

Estimation of probability to observe in JF2af2
the regression
coefficient b38 (g) 0.992
-1 -2 -3 -4 -5 -6 -7 -8 -9 -10 -11
Strong correlation between bN and lN !
log W(lN lfix)
l38 (g) ? 0.98 0.99
N38
l38 0.95 !
Wfluct(l38 0.95) ltlt 10-9
Probability to observe the total set of
experimental aligned events Wfluct ltlt 10-20 !
12

• Alignment and fluctuations

Estimation of transverse momenta in the Strana
event
Geometry Pt E Dx / H
Indirect methods
?p t? 23?7 GeV/c Preliminary !
?p t?? 40100 GeV/c Very preliminary !
QGSMs CANNOT give such p t values at E0 10 16
eV !
13

• Origin of Alignment

• The alignment phenomenon
• is produced neither by fluctuations
  nor by Earths magnetic or
  thunderstorm
  electric fields
• is caused by hadron interactions

14

• Coplanar particle generation - models

• Interpretation of alignment
• kinematic effects in diffraction processes
  (SmorSmir 90, Zhu 90, Capd 01)
• New physics
• new strong interaction at vs ? 4 TeV generation
  of bosons hadrons with new higher-color
  superheavy quarks (White 94)
• High-Qt transfer models
• standard QCD
• gluon-jet generation (Halzen 90)
• semihard double diffractive inelastic
  dissociation (SHDID) (Royzen 94) projectiles
  diquark breaking (Capd 03)
• QGS angular momentum conservation (Wibig 04)

15

Coplanar particle generation - models
Specific correlation higher pt - lower pL ?) QCD
jets Sin qi ? const ? inappropriate
correlation ? Binocular families ? NO
alignment (Lokhtin 05, e.g.) b) SHDID (Royzen,
1994) rupture of stretched quark-
gluon string (diffraction cluster) ?
appropriate correlation ? alignment can be
observed c) very-high-spin leading system
? appropriate correlation ? alignment can be
observed d) QGS angular momentum
conservation (Wibig 04) ? appropriate
correlation ? alignment can be observed

most energetic particles
16

• Coplanar particle generation - models

• QCD jets Lokhtin et al 2005
• PYTHIA _at_ vs 14 TeV (LHC) ? Conclusion
  Alignment of 3 (only !) CLUSTERS (close to
  experimental one)
• could be observed ONLY at
• E3,4jet 3 TeV, i.e. E3,4jet E1 But s
  (E3,4jet E1 )? sinel !
• Distance from interaction point to observation
  level (target thickness) Dx 0. Alignment
  drops drastically with increase of Dx
• But a) in mountain experiments Dx gt 500 g/cm2
• b) no alignment of particles and/or
  Ncluster ? 4
• QGS angular moment (Wibig 2004)
• t0 l Db and w const (Db?b/2? l const
  and w 1/Db (Db ?b/2?(v c)
• t1 wave arrears pt distribution changes

CMS
Lab
Possible (?) scheme
b/2
conservation of angular moment
-b/2
t1
t0
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• Coplanar particle generation models

• CPGM Coplanar Particle Generation Model 1), 2)
• particles (p K) are generated with
• pt ? 0.4 GeV/c transversely to the coplanarity
  plane
• pTcopl ? 2.3 GeV/c in the
  coplanarity plane
• multiplicity ns ?10

1) interaction features are related to the
fragmentation region only 2) only a primitive (!)
heuristic tool to study factors related to the
alignment observation
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Coplanar particle generation - main regularities

• F(l40.8) depends on
• depth in the atmosphere
• distance to interaction point
• If F(l40.8) 0.2 at Dx ? 500 g/cm2
  scopl sinel

p-air
background
EDCs

• Alignment can be only studied in
• high-resolution (Dx ? 1cm ) mountain
  stratospheric(or collider) experiments

hadrons
Pamir
KASCADE
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Coplanar particle generation - main regularities
Dependence of F(l4z0.8) on ZC

• F(l4z0.8) depends on ZC
• CPGM explains the effect
• Pamir CPGM data have maxima at ZC ? 4 TeVcm
• QGSMs cannot explain

20

Dependence on familiy energy
Alignment dependence on SEg
?? Experimental F(l4z0.8) depends on SEg ?
CPGM can explain the alignment ? QGSMs
cannot explain the alignment
21

Dependence on familiy energy
Ratios of ER4 R4 values in aligned and
unaligned g- families
e
Pamir (Borisov et al 2001) e 1.83
? 0.37 r 2.57 0.81
e
r
ER4 aligned gt ER4 unaligned R4 aligned
gt R4 unaligned
Nc 6, Ec 50 ???
r
CPG changes ER features of aligned g-h families
22

EAS characteristics and alignment
Why did anybody not observe earlier this process
in EAS and muon experiments? These experiments
are generally insensitive to this effect.
23

EAS characteristics and alignment
Ratio of hadron densities r(Eh gt 3 GeV) in EAS
3340 m a.s.l(Tien Shan)
rpCPGM / rpMC0
rFeMC0 / rpMC0
Difference range
Preliminary
Influence of heavy primaries is much
stronger
CPG changes EAS properties in a narrow lateral
range (?1 m)
depends on model !
24

Conclusion

• Alignment
• can be only explained by coplanar particle
  generation (ltpTcoplgt gt 2 GeV/c) at E0 ? 1016 eV
  (vs ? 4 TeV)
• can influence on lateral EAS features
• Are PCR data derived from EAS data correct
  without taking these results into account?

25

Conclusion

• Higher ?pt? ? wider lateral distribution (normal
  longitudinal !)
• could imitate (for classical EAS-array
  approach)
• more heavy composition
• higher EAS energy

Due to these reasons ?
Inconsistency of results by fluorescence
techniques and classical EAS-array approaches
What can we do ?

• collider experiments (LHC)
  to study
• high-resolution mountain experiments (Tien Shan,
  Pamirs) interactions
• development of theoretical models
• direct space experiments (INCA, ACCESS (?))
  to study the KNEE
• 
  range ? to
  tune models

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Thank you !

27

Muon-group characteristics and alignment
Multiplicity dependence of fraction of
high-energy aligned muon groups
Rmax 10 m
Rmax 100 m
Em ? 1 TeV
CPGM ltPtgt2.3 GeV/c

• High-energy muon groups are insensitive to CPG
  process
• Alignment of muon groups is mainly caused by
  Earths magnetic field

28
R.A. Mukhamedshin Institute for Nuclear
ResearchRussian Academy of Sciences, Moscow,
Russia
On concept of multipurpose astrophysical
orbital observatory for study of
high-energyprimary cosmic rays
29
Basic concept
Ltot .

• lead
• polyethylene
• Scintillators
• Helium-2 neutron counters
• SNM-17 neutron counters
• electronics boards
• photodetectors
• charge detectors (5.5?5.5 cm2 sections)
• A B sections of external part
• Ltot total
• dimension
• Lcal calorimeter
• dimension

8
A
7
5
6
B
1
2
3
4
Lcal .
30
Basic concept
Basic features of two versions (I II)
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Basic concept
Basic features of two versions (I II)
(continuation)
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Expected results
KASCADE and Tibet fits of the PCR spectrum
33
Expected results
Composition spectra

• Expected results
• PCR nucleus number
• (3-year exposure) G SW ? 20 m2?sr
• N(E0 ?1015 eV) ? 2 000
• N(E0 ? 1016 eV) ? 30

• determination of
• PCR components in the knee range
• choice between
• KASCADE and TIBET spectra
• QGSjet and SYBILL models

34
Expected results
Study of average mass number

• choice between KASCADE and TIBET spectra

35
Expected results
Study of protons-to-all particles ratio

• choice between KASCADE and TIBET spectra

36
Expected results
Study of electrons

• Expected electron number
• (3-year exposure G SW ? 20 m2?sr)
• PCR electrons number N(E0 gt1012 eV) 2 ?104

37
Expected results
Study of g-rays

• sensitivity is comparable with ground-based arrays