Some Remarks Concerning the Strong Some Remarks Concerning the Strong InteractionInteraction

Hans Gerhard Fischer

CERN

2

Layout of talkLayout of talk

1. Introduction2. Thirty-five years of collaboration with the Soltan Institute: The ISR period - conclusions in the mid-1980’s3. Thirty-five years of collaboration with the Soltan Institute: NA49 times - conclusions in the mid-2000’s4. Some concluding remarks

3

MOTTO 1MOTTO 1

´ It is a capital mistake to theorize

before one has data ´

4

MOTTO 1MOTTO 1

´ It is a capital mistake to theorize

before one has data ´

Sherlock Holmes in:

A scandal in Bohemia

Sir Arthur Conan Doyle, 1892

5

Find title « search » : 12000 entries since 1970Find title « search » : 12000 entries since 1970

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Strong coupling constant as a function of momentum transfer

Momentum transfer

αs

7

Pentaquark rush: number of papers per yearPentaquark rush: number of papers per year

8

T’Hooft’s String Configurations

«Stable configuration»Wilczek Diquark 0.1fm

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A Diquark Scattering Model for High pT Proton Production A Diquark Scattering Model for High pT Proton Production in pp Collisions at the ISRin pp Collisions at the ISR

Z.Phys. C28(1985)335

A.Breakstone, H.B.Crawley, G.M.Dallavalle, K.Doroba,D.Drijard, F.Fabbri, A.Firestone, H.G.Fischer, H.Frehse,W.Geist, G.Giacomelli, R.Gokieli, M.Gorbics, P.Hanke,M.Heiden, W.Herr, E.E.Kluge, J.W.Lamsa, T.Lohse,R.Mankel, W.T.Meyer, T.Nakada, M.Panter, A.Putzer,K.Rauschnabel, B.Rensch, F.Rimondi, M.Schmelling,G.Siroli, R.Sosnowski, M.Szczekowski, G.Ullaland,D.Wegener

ABCDHW Collaboration

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Pentaquark rush: number of papers per yearPentaquark rush: number of papers per year

11

Observation of Charmed D Meson Production in pp Observation of Charmed D Meson Production in pp CollisionsCollisions

Phys.Lett. B81(1979)250 D.Drijard, H.G.Fischer, W.Geist, R.Gokieli, P.G.Innocenti,V.Korbel, A.Minten, A.Norton, R.Sosnowski, S.Stein,O.Ullaland, H.D.Wahl (CERN)P.Bourtaud, M.DellaNegra, G.Fontaine, P.Frenkiel,C.Ghesqiere, D.Linglin, G.Sajot (College de France)H.Frehse, E.E.Kluge, M.Heiden, A.Putzer, J.Stiewe(Heidelberg)P.Hanke, W.Hofmann, M.Panter, K.Rauschnabel,J.Spengler, D.Wegener (Karlsruhe)

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13

Further Investigation of Beauty Baryon Production at the Further Investigation of Beauty Baryon Production at the ISRISR

Phys.Lett. B108(1982)361

D.Drijard, H.G.Fischer, H.Frehse, W.Geist, P.G.Innocenti,J.W.Lamsa, W.T.Meyer, A.Norton, O.Ullaland, H.D.Wahl(CERN)G.Fontaine, C.Ghesquiere, G.Sajot (College de France)W.Hofmann, M.Panter, K.Rauschnabel, J.Spengler,D.Wegener (Dortmund)P.Hanke, M.Heiden, E.E.Kluge, T.Nakada, A.Putzer(Heidelberg)M.DellaNegra, D.Linglin (LAPP Annecy)R.Gokieli, R.Sosnowski (Warsaw)

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Angular Distributions of Charged Particles between 30 and Angular Distributions of Charged Particles between 30 and 90 Degrees at ISR Energies90 Degrees at ISR Energies

Phys.Lett. B39(1972)654

M.Breidenbach, G.Charpak, G.Coignet, D.Drijard,

H.G.Fischer, G.Fuegge, Ch.Gottfried, H.Grote,

A.Minten, F.Sauli, M.Szeptycka, E.G.H.Williams

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Angular distribution of charged particles (pseudorapidity)

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Pseudorapidity distributions at different energies

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The rising rapidity plateau

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Split Field Magnet Spectrometer

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Acceptance coverage of experiments in xAcceptance coverage of experiments in xF F and pand pTT

GeVs 2010

GeVs 6020

GeVs 200

TeVs 140.0 0.5 1.0

xF

0

0.5

1

1.5

2

pT [

GeV

]

0.0 0.5 1.0xF

0

0.5

1

1.5

2

pT [

Ge

V]

SPS ISR

RHIC LHC

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Inclusive Charged Particle Cross Sections from ppInclusive Charged Particle Cross Sections from ppInteractions at ISR EnergiesInteractions at ISR Energies

Z.Phys. C69(1995)55A.Breakstone, H.B.Crawley, A.Firestone, M.Gorbics, L.D.Isenhower, J.W.Lamsa, W.T.Meyer (Ames)R.Campanini, M.Cuffiani, G.M.Dallavalle, M.Deninno, F.Fabbri, G.Giacomelli,F.Rimondi, G.Siroli (Bologna)D.Drijard, H.G.Fischer, W.Geist, G.Mornacchi, M.Panter,O.Ullaland, R.Yeung (CERN)T.Lohse, R.Mankel, K.Rauschnabel, M.Schmelling,D.Wegener (Dortmund)H. Floege, H.Frehse, L.Gesswein, P.Hanke, M.Heiden,W.Herr, E.E.Kluge, T.Nakada, A.Putzer, B.Rensch(Heidelberg)K.Doroba,R.Gokieli, R.Sosnowski, M.Szczekowski(Warsaw)

ABCDHW Collaboration

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Piminus xF Distributions from ISRPiminus xF Distributions from ISR

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Feynman x distributions of positive pions from ISR (CHLM Collaboration)

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‘‘Hard Parton Scattering’Hard Parton Scattering’

f(pT) = pT- 4 f(xT)

xT = 2pT / √s

Experimentally found at ISR:

For pions f(pT) = pT - 8 f(xT)

For protons f(pT) = pT - 12 f(xT)

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Observation of Jet Structure in High p(T) Events at the ISRObservation of Jet Structure in High p(T) Events at the ISRand the Importance of Parton Transverse Momentumand the Importance of Parton Transverse Momentum

Nucl.Phys. B127(1977)1

M.DellaNegra, D.Drijard, H.G.Fischer, G.Fontaine,

H.Frehse, P.Frenkiel, C.Ghesquiere, R.Gokieli, P.Hanke,

W.Hofmann, P.G.Innocenti, W.Isenbeck, E.E.Kluge,

V.Korbel, D.Linglin, A.Minten, A.Norton, A.Putzer, G.Sajot,

R.Sosnowski, S.Stein, J.Stiewe, H.D.Wahl, D.Wegener

CCHK COLLABORATION

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Steepen up predicted pT distribution by introducing parton transverse

momentum

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First order QCD with parton intrinsic transverse momentumFirst order QCD with parton intrinsic transverse momentum

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One of the first complete  models of event structure with hardparton scattering

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Push limit of pPush limit of pTT up to 12 GeV/c up to 12 GeV/c

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Add initial and final state gluon radiationAdd initial and final state gluon radiation

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Flavour Tagging of Parton Jets and SeparationFlavour Tagging of Parton Jets and Separationof Parton Subprocesses in Hard pp Collisions at the ISRof Parton Subprocesses in Hard pp Collisions at the ISR

Z.Phys.C25(1984)21

A.Breakstone, C.D.Buchanan, R.Campanini, H.B.Crawley, M.Dallavalle,

K.Doroba, D.Drijard, F.Fabbri, A.Firestone, H.G.Fischer, H.Frehse, W.Geist,

G.Giacomelli, R.Gokieli, M.Gorbics, P.Hanke, M.Heiden, W.Herr, E.E.Kluge,

J.W.Lamsa, T.Lohse, W.T.Meyer, G.Mornacchi, T.Nakada, M.Panter, A.Putzer,

K.Rauschnabel, F.Rimondi, R.Sosnowski, M.Szczekowski, O.Ullaland,

D.Wegener

ABCDHW Collaboration

31

A Diquark Scattering Model for High pT Proton Production A Diquark Scattering Model for High pT Proton Production in pp Collisions at the ISRin pp Collisions at the ISR

Z.Phys. C28(1985)335

A.Breakstone, H.B.Crawley, G.M.Dallavalle, K.Doroba,D.Drijard, F.Fabbri, A.Firestone, H.G.Fischer, H.Frehse,W.Geist, G.Giacomelli, R.Gokieli, M.Gorbics, P.Hanke,M.Heiden, W.Herr, E.E.Kluge, J.W.Lamsa, T.Lohse,R.Mankel, W.T.Meyer, T.Nakada, M.Panter, A.Putzer,K.Rauschnabel, B.Rensch, F.Rimondi, M.Schmelling,G.Siroli, R.Sosnowski, M.Szczekowski, G.Ullaland,D.Wegener

ABCDHW Collaboration

32

Introduce Hard Diquark Scattering and Form FactorIntroduce Hard Diquark Scattering and Form Factor

f(pT) ~ pT- 4 (1+Q2/M2) – 1 f(xT)

+ diquark structure function

+ diquark fragmentation function

fit M2 M2 ~ 10 – 20 GeV2

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Fits to the observed p/pion ratio as a function of transverse momentum

pT

p/pi ratio

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Conclusions from ISR 1970-1990Conclusions from ISR 1970-1990

• Parton dynamics manifest in all areas of hadronic

interactions:

- rising central rapidity plateau (gluons, sea quarks)

- forward particle production pictures valence partons

(counting rules)

- hard parton scattering leads to high pT production

(perturbative QCD already applicable in the few

GeV/c region)• Underlying mechanism: Intermediate partonic state

present in all hadronic interactions, initiated by gluon exchange = colour exchange strings

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MOTTO 2MOTTO 2

‘ It is the nature of an hypothesis, when once a man has conceived it, that it assimilates

everything to itself as proper nourishment, and, from the first moment of your begetting it, it generally grows the stronger by everything you see, hear, read or understand.’

Tristram Shandy Laurence Sterne, 1750

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On the Hadronic Production of Lepton Pairs from Heavy On the Hadronic Production of Lepton Pairs from Heavy Flavour DecayFlavour Decay

Z.Phys. C19(1983)159

H.G.Fischer and W.M.Geist (CERN)

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Lepton pair mass spectra fitted with combination of DDbar and BBar semileptonic decays

Watch upper limits Of cross sections

DDbar: 6 microbarn at SPS 25 microbarn at ISR

BBbar 50 nbarn

at sqrt(s)=27 GeV

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Layout of NA49 experimentLayout of NA49 experiment

Zestaw dużych

Komór Projekcji Czasowej

(TPC) detektory śladowe

połączone

z identyfikacją cząstek przez

pomiardx

dE

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Inclusive production of charged pions in p+p collisions at Inclusive production of charged pions in p+p collisions at 158 GeV/c beam momentum158 GeV/c beam momentum

Eur.Phys.J. C45 (2006) 343

C.Alt, T.Anticic, B.Baatar, D.Barna, J.Bartke, L.Betev, H.Bialkowska, C.Blume,

B.Boimska, M.Botje, J.Bracinik, P.Buncic, V.Cerny, P.Christakoglou, O.Chvala,

P.Dinkelaker, J.Dolejsi, V.Eckardt, H.G.Fischer, D.Flierl,Z.Fodor, P.Foka, V.Friese,

M.Gazdzicki, K.Grebieszkov, C.Hoehne, K.Kadija, A.Karev, M.Kliemant, S.Kniege,

V.I.Kolesnikov, E.Kornas, R.Korus, M.Kowalski, I.Kraus, M.Kreps, M.vanLeeuwen,

B.Lungwitz, M.Makariev, A.I.Malakhov, M.Mateev, G.L.Melkumov, M.Mitrovski,

S.Mrowczynski, G.Palla, D.Panayotov, A.Petridis, R.Renfordt, M.Rybczinsky,

A.Rybicki, A.Sandoval, N.Schmitz, T.Schuster, P.Seyboth, F.Sikler, E.Skrzypczak,

G.Stefanek, R.Stock, H.Stroebele, T.Susa, J.Sziklai, P.Szymanski, V.Trubnikov,

D.Varga, M.Vassiliou, G.I.Veres, G.Vesztergombi, D.Vranik, S.Wenig,, A.Wetzler,

Z.Wlodarczyk, I.K.Yoo

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Inclusive pion cross sections as a function of pT for different xF

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Inclusive pion cross sections as a function of xF for different pT

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Inclusive pion cross sections for p+Carbon minimum bias collisions

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Status of final data analysisStatus of final data analysis

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Pions in pPb (1)Pions in pPb (1)

= 4.2

45

Pions in pPb (2)Pions in pPb (2)

= 5.2

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Pions in PbPb Pions in PbPb

150<nch<300

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Pions in PbPb Pions in PbPb

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Linear plot of pion cross section in p+p interactions

49

Contribution from known Delta++ and Delta+ cross section

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Data

M=1.232 GeVno Breit-Wigner

Relativistic Breit-Wigner

3 dimensional plot of pi+ cross section

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Projection of 3 dimensional plot on xF and pT

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Resonance treatment in « microscopic » models

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Feynman x distribution of pion density dN/dx

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ppTT distributions at different x distributions at different xFF compared to compared to

resonance decayresonance decay

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Prediction from resonance decay up to pPrediction from resonance decay up to pTT=3 GeV/c=3 GeV/c

compared to existing measurements as a function of compared to existing measurements as a function of √√ss

57

Back to central rapidity plateau:Back to central rapidity plateau:

ppTT dependence at different s dependence at different s

xF = 0

R = ratioto NA49

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Back to central rapidity plateau:Back to central rapidity plateau:

ppTT dependence at different s dependence at different s

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Back to central rapidity plateau:Back to central rapidity plateau:

ppTT dependence at different s dependence at different s

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s dependence of pion production at fixed ps dependence of pion production at fixed pTT

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Conclusions from NA49 2008Conclusions from NA49 2008

• What about the intermediate partonic phase?• What about the partonic central production

mechanism?• What about the trace of valence partons in forward

production?• What about the Drell-Yan mechanism?• What about partonic hard scattering?• Where is the shadow line between perturbative

and non-perturbative QCD?

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Could it be that:Could it be that:

- there is no intermediate partonic phase

- there is no direct manifestation of partonic structure

and dynamics, examples: - absence of tightly bound diquarks, pentaquarks

(exotics in general?)

- alternative explanation for « rising rapidity plateau » and

forward hadron production

- the « shadow line » between soft and hard processes

is much higher in momentum transfer than generally

assumed

63

Could it finally be that:Could it finally be that:

- soft hadronic production is governed by high

mass resonance excitation and cascading

decay,

- not as assumed by thermodynamics

- not as used in « microscopic » models

- not as precribed by string fragmentation- experimentation should play a new role in a

situation where theory evidently breaks

down : the tools for this are available!

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Motto1 completed:Motto1 completed:

‘It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories instead of theories to suit facts’

Sherlock Holmes