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Rauf Mukhamedshin Institute for Nuclear Research Moscow Russia

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. Introduction. Traditional ground-based EAS arrays detect lateral distributions of secondary particles (e  or m  )

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Rauf Mukhamedshin Institute for Nuclear Research Moscow Russia

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  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, <pt>, observation depth etc. • The larger is <pt>, the higher could be the estimated EAS energy r (r) larger <pt> lower <pt> 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) XRECsaboard balloons and airplanes Ethr> 4 TeV XRECs of “PAMIR” experiment «Carbon» C-XREC «Lead» Pb-XREC

  5. XREC Experimental data cik=Rik (EiEk)1/2 ~ 2Zik Energetically Distinguished Cores(EDC) =isolatedclusters of particles(g,e,h)joined with“decascading” p p± procedure –merging of close(Zik< ZC) i-th and k-th particles for reconstruction of “initial” g-rays: ZС ~ 1 TeV·cm p0-mesons: ZС ~ 3TeV·cm hadrons: ZС ~ 20TeV·cm 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: l4=0.95;c)Pb-28: l4=0.85. d)JF2af2event (“Concorde”); e)Strana event (balloon). Digitals mean energy in TeV j -1/(N-1)≤lN≤ 1.0 Aligned event:lN≥ lfixUsually: l4≥0.8 k jkij i

  7. Experimental data on alignment Fraction of aligned families “Pamir” Experiment (SEg≥ 700 TeV, l4 ≥0.8) • 0.430.13 inPb-XREC(6 from 14, 1.0 expected) • 0.270.09 in С- XREC (9 from 35, 2.1 expected) Expected background:0.06 Kanbaladata(SEg≥500 TeV, l3 ≥0.8) • 0.50.2 inFe-XREC(3 from6, 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 electricfield? Strong interactions?

  8. Simulation Code MC0 QGSM-type model describes “PAMIR” Collaboration’s data at <E0> ≲5·1015 eV (√s ≲3 TeV) and a lot of accelerator data close toQGSJET 98 (CORSIKA) in features and simulation results Alignment and fluctuations Binomial distribution: Probability to observekaligned events in a set ofnevents: _____________ s= npq

  9. Alignment and fluctuations Probability to observe the total set of experimentalaligned events (Pamir, Kanbala, stratosphere): Wfluct~0.910-41.510-4910-2310-3610-4<10–14 It is an upper limit only !

  10. 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 N=38 l38 ≥ 0.95 ! Wfluct(l38 ≥ 0.95) <<10-9 Probability to observe the total set ofexperimentalaligned events Wfluct<<10-20 !

  11. Alignment and fluctuations Estimation of transverse momenta in the “Strana”event Geometry: Pt = E Dx / H Indirect methods pt=237 GeV/cPreliminary ! pt≃40–100 GeV/cVery preliminary ! QGSMs CANNOT give such pt values at E0 ~ 1016 eV !

  12. Origin of Alignment The alignment phenomenon • is produced neither by fluctuations nor by Earth’s magnetic or thunderstorm electricfields • is caused by hadron interactions

  13. Coplanar particle generation - models Interpretation of alignment • kinematic effects in diffraction processes (SmorSmir 90, Zhu 90, Capd 01); “New” physics • new strong interaction at √s≳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); projectile’s diquark breaking (Capd 03) • QGS angular momentum conservation (Wibig 04)

  14. Coplanar particle generation - models Specific correlation:higherpt− lowerpL а) QCD jets:Sinqi const inappropriate correlation “Binocular”families  NOalignment (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-spinleadingsystem appropriate correlation alignment can be observed d) QGS angular momentum conservation (Wibig 04)appropriate correlation alignment can be observed most energetic particles

  15. Coplanar particle generation - models QCDjets:Lokhtin et al2005 PYTHIA@√s=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~ E1But:s (E3,4jet~ E1)⋘ sinel ! • Distance frominteraction pointtoobservation level(target thickness) Dx ~0. Alignment drops drastically with increase of Dx But:a)in mountain experimentsDx > 500 g/cm2 b)no alignment ofparticlesand/or Ncluster4 QGS’ angular moment(Wibig 2004) t0– l ~ Dbandw~const(Db≪b/2l ~const andw~1/Db(Db~b/2(v = c) t1 – wave arrears; pt distribution changes CMS Lab Possible (?) scheme b/2 conservation ofangular moment -b/2 t0 t1

  16. Coplanar particle generation models CPGM=Coplanar Particle Generation Model1), 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

  17. Coplanar particle generation - main regularities F(l4≥0.8) depends on • depth in the atmosphere • distance to interaction point If F(l4≥0.8) 0.2 at Dx ≳ 500 g/cm2scopl~sinel p-air background EDCs Alignment can be only studied in • high-resolution (Dx ≲1cm ) mountain & stratospheric(or collider) experiments hadrons “Pamir” KASCADE

  18. Coplanar particle generation - main regularities Dependence ofF(l4z0.8) onZC F(l4z0.8)depends on ZC CPGMexplains the effect “Pamir’ & CPGM data have maxima at ZC 4 TeV·cm QGSMscannot explain

  19. Dependence on familiy energy Alignment dependence onSEg ▲∆ Experimental F(l4z0.8)depends on SEg □CPGMcan explain the alignment QGSMscannot explain the alignment

  20. Dependence on familiy energy Ratios of ‹ER›4 & ‹R›4values in aligned and unaligned g- families e “Pamir” (Borisov et al 2001) *e= 1.830.37 r= 2.57±0.81 e r ‹ER›4 aligned >‹ER›4 unaligned‹R›4 aligned > ‹R›4 unaligned; *Nc≥ 6, Ec ≥ 50 ТэВ r CPG changes ER features ofaligned g-h families

  21. 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.

  22. EAS characteristics and alignment Ratio of hadron densities r(Eh > 3 GeV) in EAS 3340 m a.s.l(Tien Shan) rpCPGM / rpMC0rFeMC0 / 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 !

  23. Conclusion Alignment • can be only explained bycoplanar particle generation (<pTcopl> >2GeV/c) at E0≳1016eV (√s ≳ 4 TeV) • caninfluence on lateral EASfeatures Are PCR data derived from EAS data correct without taking these results into account?

  24. Conclusion Higher pt wider lateral distribution (normal longitudinal !) could imitate (for classical EAS-array approach) • more heavy composition • higher EAS energy Due tothese 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

  25. Thank you !

  26. Muon-group characteristics and alignment Multiplicity dependence of fraction of high-energyaligned muon groups Rmax = 10 m Rmax =100 m Em 1 TeV CPGM: <Pt>=2.3 GeV/c High-energy muon groups are insensitive to CPG process Alignment of muon groups is mainly caused by Earth’s magnetic field

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

  28. Ltot . Basic concept 8 • lead • polyethylene • Scintillators • Helium-2 neutron counters • SNM-17 neutroncounters • electronicsboards • photodetectors • chargedetectors (5.55.5 cm2sections) A&B – sections of external part Ltot– total dimension Lcal– calorimeter dimension A 7 5 6 B 1 2 3 4 Lcal .

  29. Basic features of two versions (I & II) Basic concept

  30. Basic features of two versions (I&II) (continuation) Basic concept

  31. “KASCADE” and “Tibet” fits of the PCR spectrum Expected results

  32. Composition & spectra Expected results Expected results: • PCR nucleusnumber (3-yearexposure) 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 andSYBILL models

  33. Study of average mass number Expected results • choice between “KASCADE”and“TIBET” spectra

  34. Study of protons-to-all particles ratio Expected results • choice between “KASCADE”and“TIBET” spectra

  35. Study of electrons Expected results Expected electron number (3-year exposure &G = SW 20 m2sr): • PCR electrons numberN(E0 >1012eV)~ 2 104

  36. Study of g-rays Expected results • sensitivity is comparable with ground-based arrays

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