Particle Production from a HERA perspective
Daniel Traynor, Birmingham seminar 15/10/09
NON-PERTURBATIVE
1
Particle Production from a HERA perspective Daniel Traynor, - - PowerPoint PPT Presentation
NON-PERTURBATIVE Particle Production from a HERA perspective Daniel Traynor, Birmingham seminar 15/10/09 1 Overview The Trouble With QCD. HERA and the H1 experiment. Fragmentation functions. Strangeness production. Bonus : More
NON-PERTURBATIVE
1
The Trouble With QCD. HERA and the H1 experiment. Fragmentation functions. Strangeness production. Bonus : More strangeness, Instantons, Pentaquarks, Glueballs
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QED TO CUT A LONG STORY SHORT. THE INVARIANCE OF THE QED LAGRANGIAN UNDER LOCAL GAUGE TRANSFORMATIONS REQUIRES THE EXISTENCE OF A GAUGE FIELD. THIS IS THE ELECTROMAGNETIC FIELD AND MEDIATES THE FORCE BETWEEN CHARGED PARTICLES THE QUANTA OF THIS FIELD ARE THE MASSLESS PHOTONS
U(1) SYMMETRY ABELIAN VECTOR FIELD Aμ (GAUGE FIELD) WHICH COUPLES TO
SYMBOLICALLY THE QED LAGRANGIAN HAS THESE TERMS FIELD STRENGTH TENSOR
Fµν = δµAν − δνAµ
PROPAGATION OF CHARGED PARTICLES PROPAGATION OF PHOTONS INTERACTION OF PHOTONS AND CHARGED PARTICLES
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SU(3) SYMMETRY NON-ABELIAN
QCD TO CUT A LONG STORY SHORT. THE INVARIANCE OF THE QCD LAGRANGIAN UNDER LOCAL GAUGE TRANSFORMATIONS REQUIRES THE EXISTENCE OF A GAUGE
MEDIATES THE FORCE BETWEEN COLOURED
THE MASSLESS GLUONS
VECTOR FIELD Aμ (GAUGE FIELD) WHICH COUPLES TO
FIELD STRENGTH TENSOR
Fµν = δµAν − δνAµ − ig[AµAν − AνAµ]
SELF INTERACTION TERM SYMBOLICALLY THE QCD LAGRANGIAN HAS THESE TERMS
THREE AND FOUR GLUON VERTICES
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R, 1/Q ELECTRIC CHARGE SCREENING OF ELECTRIC CHARGE IN QED HIGHER ORDER PROCESSES ARE LESS IMPORTANT DUE TO THE SMALLNESS OF αem (1/137).
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R, 1/Q ELECTRIC CHARGE SCREENING OF ELECTRIC CHARGE IN QED HIGHER ORDER PROCESSES ARE LESS IMPORTANT DUE TO THE SMALLNESS OF αem (1/137). ANTI SCREENING OF COLOUR CHARGE R, 1/Q COLOUR CHARGE AT LARGE DISTANCES αs BECOMES LARGE (~1) AND HIGHER ORDER PROCESSES BECOME MORE IMPORTANT ASYMPTOTIC FREEDOM AT SMALL DISTANCES R ~1/Λ~10-15M PERTURBATION THEORY FAILS
αs(Q) ∼ 2π 7ln(Q/Λ)
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QED αem α2em α3em THE PERTURBATIVE EXPANSION
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QED αem α2em α3em QCD αs α2s
e+ p e+ * q q Q2 x
x0, k0 xi, ki xi+1, ki+1
αns THE PERTURBATIVE EXPANSION
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NLO time-like splitting functions (diagonal singlet)
P(1)
ns,+(x) ≡ P(1)T ns,+ (x)−P(1)S ns,+(x) =
4CF
2
H0(6(1−x)−1 −5−x)+H0,0(−8(1−x)−1 +6+6x)+(H1,0 +H2)(−8(1−x)−1 +4+4x)
P(1)
ps (x) ≡ P(1)T ps
(x)−P(1)S
ps
(x) = 8CFnf
P(1)
gg (x) ≡ P(1)T gg
(x)−P(1)S
gg
(x) = 8C2
A
−8(1+x)H0,0
+[4+6x+4/3(x−1 +x2)]H0 +2(1+x)H0,0
α2s q→q(g) g→g(g) g→qqg ...
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NLO time-like splitting functions (diagonal singlet)
P(1)
ns,+(x) ≡ P(1)T ns,+ (x)−P(1)S ns,+(x) =
4CF
2
H0(6(1−x)−1 −5−x)+H0,0(−8(1−x)−1 +6+6x)+(H1,0 +H2)(−8(1−x)−1 +4+4x)
P(1)
ps (x) ≡ P(1)T ps
(x)−P(1)S
ps
(x) = 8CFnf
P(1)
gg (x) ≡ P(1)T gg
(x)−P(1)S
gg
(x) = 8C2
A
−8(1+x)H0,0
+[4+6x+4/3(x−1 +x2)]H0 +2(1+x)H0,0
α2s
LO results@
NNLO time-like splitting functions (diagonal singlet)
P(2) ps,+(x) ≡ P(2)T ps,+ (x)−P(2)S ps,+(x) = +16C3 FS.M., Vogt ‘07
α3s q→q(g) g→g(g) g→qqg ...
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R, 1/Q COLOUR CHARGE R ~1/Λ~10-15M PERTURBATION THEORY FAILS CONFINEMENT HAPPENS IN THE REGION WHERE PERTURBATION THEORY FAILS WE HAVE TO USE MODELS OF WHAT WE THINK IS HAPPENING BUT BASED ON QCD. THESE MODELS CAN HAVE DIFFERENT ASSUMPTIONS AND A VERITY OF PARAMETERS. THESE ASSUMPTIONS AND PARAMETERS NEED TO BE CONFRONTED WITH AND TUNED TO DATA FACTORISATION SPLIT THE THEORY INTO PARTS; SHORT DISTANCES WHERE PREDICTIONS CAN BE MADE LARGE DISTANCES WHERE APPROXIMATIONS HAVE TO BE MADE QUARKS MUST FRAGMENT IN TO HADRONS WITH UNIT PROBABILITY
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STARTING SCALE GIVEN BY HARD SCALE Q PROBABILITY OF PARTON EMISSION GIVEN BY THE “QCD” SPLITTING FUNCTIONS, REDUCING Q AT SOME FIXED VALUE “Q0” THE EVOLUTION IS STOPPED AND THE PARTONS ARE HADRONISED !""# '()*+,-.(/-+, !5#26789:26 ';<= &%>?<;@>&A% !#B) C<;DE?%>;>&A% F!#B) G!;<>A%7@;H@;=?I %!#B)
DETECTOR
Hard scale: Q2 = −q2
LO , NLO ME DGLAP, BFKL, CCFM, MLLA ETC.. LPHD, STRING, CLUSTER
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COMPLEXITY
PETRA, SLC,LEP
VACUUM MEDIUM
10
COMPLEXITY
HERA PETRA, SLC,LEP
VACUUM MEDIUM
10
COMPLEXITY
TEVATRON RHIC,LHC HERA PETRA, SLC,LEP
VACUUM MEDIUM
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COMPLEXITY
HERMES CLAS TEVATRON RHIC,LHC HERA PETRA, SLC,LEP
VACUUM MEDIUM
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COMPLEXITY
HERMES CLAS TEVATRON RHIC,LHC HERA PETRA, SLC,LEP
VACUUM MEDIUM
RHIC LHC
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HSV STADIUM TRABRENNEN AIRPORT
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HSV STADIUM TRABRENNEN AIRPORT
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HSV STADIUM TRABRENNEN AIRPORT
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HSV STADIUM TRABRENNEN AIRPORT
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PROTON 920 GEV e± 27.5 GEV
Days of running H1 Integrated Luminosity / pb
Status: 1-July-2007 500 1000 1500 100 200 300 400
electrons positrons low E
HERA-1 HERA-2
∼0.5 fb-1 PER EXPERIMENT 1992 - 2007
Protons 920 Electrons 27.6
+ LOW ENERGY PROTON RUN TO MEASURE FL
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ASYMMETRIC BEAM ENERGIES = ASYMMETRIC DETECTOR 920 GEV PROTONS 27.5 GEV ELECTRONS 1.16 T SOLENOID, RADIUS 2.7 M (ALEPH LIKE) UNIFORM FIELD FOR TRACKING (CENTRAL AND FORWARD)! COIL OUTSIDE CALORIMETER FOR BEST RESOLUTION!
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± 1.74 η, pt > 0.12 GeV
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“virtuality” “inelasticity”
relationship “Quark momentum”
√S = 318 GeV
γ/Z DIS, BORN LEVEL
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16
1 Q increasing
XP = SCALED MOMENTUM VARIABLE Q/2 = SCALE IN CURRENT REGION OF BREIT FRAME PH = MOMENTUM OF CHARGED PARTICLE IN CURRENT REGION OF BREIT FRAME D(XP) = EVENT NORMALISED, CHARGED PARTICLE, SCALED MOMENTUM DISTRIBUTION AS Q INCREASES D(XP) GETS SOFTER, I.E. MORE TRACKS WITH SMALL SHARE OF INITIAL SCALE
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SCALING VIOLATIONS, A PREDICTION OF QCD, SENSITIVE TO αs PETRA / SLC / LEP
Q INCREASING
Pji(xp, αs) = P (0)
ji (xp) + αs
2π P (1)
ji (xp) + ...
DGLAP SPLITTING FUNCTION
αs(Q) ∼ 2π 7ln(Q/Λ)
Q ~ Q0, NO ROOM FOR GLUON EMISSION . 1 , 3 . 5 . 7 . 9 XP CUT OFF
LOG DEPENDENCE ON Q
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SCALING VIOLATIONS, A PREDICTION OF QCD, SENSITIVE TO αs PETRA / SLC / LEP
Q INCREASING
Pji(xp, αs) = P (0)
ji (xp) + αs
2π P (1)
ji (xp) + ...
DGLAP SPLITTING FUNCTION
αs(Q) ∼ 2π 7ln(Q/Λ)
Q ~ Q0, NO ROOM FOR GLUON EMISSION . 1 , 3 . 5 . 7 . 9 XP CUT OFF
LOG DEPENDENCE ON Q
. 1 , 3 . 5 . 7 . 9 Q > Q0, PROBABILITY OF GLUON EMISSION (E.G. 50%, 1/2 P) XP
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SCALING VIOLATIONS, A PREDICTION OF QCD, SENSITIVE TO αs PETRA / SLC / LEP
Q INCREASING
Pji(xp, αs) = P (0)
ji (xp) + αs
2π P (1)
ji (xp) + ...
DGLAP SPLITTING FUNCTION
αs(Q) ∼ 2π 7ln(Q/Λ)
Q ~ Q0, NO ROOM FOR GLUON EMISSION . 1 , 3 . 5 . 7 . 9 XP CUT OFF
LOG DEPENDENCE ON Q
. 1 , 3 . 5 . 7 . 9 Q > Q0, PROBABILITY OF GLUON EMISSION (E.G. 50%, 1/2 P) XP . 1 , 3 . 5 . 7 . 9 Q >> Q0, ROOM FOR MORE EMISSIONS XP
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! "#$% "#$% ! !
!"#$%&'"()#
PROVIDES CLEAREST SEPARATION BETWEEN PARTICLES FROM HARD SCATTERING AND PROTON REMNANT. ALLOWS FOR EASY COMPARISON WITH e+e− DATA CURRENT REGION ENERGY SCALE IS Q/2 BOOST TO BREIT FRAME MEANS WE MEASURE DOWN TO MOMENTUM =0!
ep→eX e+e-→qq
CURRENT TARGET
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KINEMATIC PHASE SPACE 100 < Q2 < 20,000 GeV2 0.05 < y < 0.6 θELECTRON>150° 30° < θQ,LAB < 150° CORRECTION FACTOR < 1.2. DOMINATED BY BOOST TO BREIT FRAME. CORRECTION FOR TRACKING EFFICIENCIES VERY SMALL QUARK SCATTERING ANGLE, θQ,LAB, CALCULATED FROM KINEMATICS. ENSURES CURRENT REGION OF BREIT FRAME REMAINS WITHIN TRACKING ACCEPTANCE. EASY TO CALCULATE IN THEORY! SYSTEMATIC ERROR ~5% K0, Λ, ETC.. CONSIDERED AS STABLE
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Q,E* (GeV)
10
210
p
1/N dn/dx
50 100 150 200
< 0.02
p
0 < x H1 Data
DELPHI TASSO MARKII AMY
Q,E* (GeV)
10
210
p
1/N dn/dx
20 40 60 80 100
< 0.05
p
0.02 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
10 15 20 25 30 35
< 0.1
p
0.05 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
6 8 10 12
< 0.2
p
0.1 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
1 2 3 4 5
< 0.3
p
0.2 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
1 1.5 2
< 0.4
p
0.3 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
0.4 0.6 0.8 1
< 0.5
p
0.4 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
0.2 0.3 0.4
< 0.7
p
0.5 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
0.02 0.04 0.06
< 1.0
p
0.7 < x
PRETTY GOOD AGREEMENT BETWEEN ep AND e+e- ! NB: SUPPRESSED ZEROS
GLUON COHERENCE
21
Q,E* (GeV)
10
210
p
1/N dn/dx
50 100 150 200
< 0.02
p
0 < x H1 Data
DELPHI TASSO MARKII AMY
Q,E* (GeV)
10
210
p
1/N dn/dx
20 40 60 80 100
< 0.05
p
0.02 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
10 15 20 25 30 35
< 0.1
p
0.05 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
6 8 10 12
< 0.2
p
0.1 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
1 2 3 4 5
< 0.3
p
0.2 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
1 1.5 2
< 0.4
p
0.3 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
0.4 0.6 0.8 1
< 0.5
p
0.4 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
0.2 0.3 0.4
< 0.7
p
0.5 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
0.02 0.04 0.06
< 1.0
p
0.7 < x
PRETTY GOOD AGREEMENT BETWEEN ep AND e+e- ! LARGE DIFFERENCE AT HIGH Q AND SMALL XP REASON UNCLEAR NB: SUPPRESSED ZEROS
GLUON COHERENCE
21
Q,E* (GeV)
10
210
p
1/N dn/dx
50 100 150 200
< 0.02
p
0 < x H1 Data
DELPHI TASSO MARKII AMY
Q,E* (GeV)
10
210
p
1/N dn/dx
20 40 60 80 100
< 0.05
p
0.02 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
10 15 20 25 30 35
< 0.1
p
0.05 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
6 8 10 12
< 0.2
p
0.1 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
1 2 3 4 5
< 0.3
p
0.2 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
1 1.5 2
< 0.4
p
0.3 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
0.4 0.6 0.8 1
< 0.5
p
0.4 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
0.2 0.3 0.4
< 0.7
p
0.5 < x
Q,E* (GeV)
10
210
p
1/N dn/dx
0.02 0.04 0.06
< 1.0
p
0.7 < x
PRETTY GOOD AGREEMENT BETWEEN ep AND e+e- ! LARGE DIFFERENCE AT HIGH Q AND SMALL XP REASON UNCLEAR LOW Q, MID XP. EXPECTED TO BE DUE TO BGF KINEMATICS PRODUCING EMPTY CURRENT REGION NB: SUPPRESSED ZEROS
GLUON COHERENCE
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Rapgap Dir
DGLAP CDM
LEPTO (PARTON SHOWERS + STRING) ARIADNE (COLOUR DIPOLE MODEL + STRING) SCI (LEPTO + SOFT COLOUR INTERACTIONS)
∼ ΣmnAmnln(Q2)mln(1/x)n
RESUM ln(Q2) TERMS, ORDER PARTON EMISSION STRONGLY WITH KT. DGLAP “LIKE” BFKL “LIKE” RESUM ln(1/X) TERMS, WEAK KT ORDERING.
GLUON COHERENCE
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CLUSTER HADRONISATION (HERWIG) LUND STRING HADRONISATION
Mesons q q distance
time Mesons qq q q g ! P c1 beam cluster
short distances.
+ – + –
QED QCD
LINEAR INTERQUARK POTENTIAL THE PARTON SHOWER NATURALLY PRECONFINES COLOURED OBJECTS TOGETHER (CLUSTERS) WHICH CAN BE COMBINED INTO COLOURLESS MESONS
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Q (GeV)
10
210
p
/dx 1/N dn
50 100 150 200
< 0.02
p
0 < x H1 Data
HERWIG PS+SCI CDM PS
Q (GeV)
10
210
p
/dx 1/N dn
20 40 60 80 100
< 0.05
p
0.02 < x
Q (GeV)
10
210
p
/dx 1/N dn
10 15 20 25 30 35
< 0.1
p
0.05 < x
Q (GeV)
10
210
p
/dx 1/N dn
6 8 10 12
< 0.2
p
0.1 < x
Q (GeV)
10
210
p
/dx 1/N dn
1 2 3 4 5
< 0.3
p
0.2 < x
Q (GeV)
10
210
p
/dx 1/N dn
1 1.5 2
< 0.4
p
0.3 < x
Q (GeV)
10
210
p
/dx 1/N dn
0.4 0.6 0.8 1
< 0.5
p
0.4 < x
Q (GeV)
10
210
p
/dx 1/N dn
0.2 0.3 0.4
< 0.7
p
0.5 < x
Q (GeV)
10
210
p
/dx 1/N dn
0.02 0.04 0.06
< 1.0
p
0.7 < x
CDM AND PS ACCEPTABLE DESCRIPTION OF DATA. BOTH TEND TO OVERESTIMATE THE MULTIPLICITY AT HIGH Q SCI MODEL PREDICTS TOO SOFT A SPECTRUM HERWIG IS TOO HARD AND FAILS TO REPRODUCE SCALING VIOLATIONS SEEN IN THE DATA
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σh = PDF ⊗ M.E. ⊗ FF NLO PQCD FRAGMENTATION FUNCTIONS - e+e- FITS CYCLOPS INFRA RED SAFE REGION (Q2>100), XP > 0.1 FF PARAMETERISED FROM XP>0.1 HIGHEST Q2 BIN (8,000 - 20,000) LOW IN STATISTICS. CTEQ6M, Λ(5)QCD = 226 MEV (ALSO ME + FF) Dhi(XP,Q) GIVES THE DISTRIBUTION OF MOMENTUM FRACTION XP FOR HADRONS OF TYPE h IN A JET INITIATED BY A PARTON OF TYPE i PRODUCED IN A HARD PROCESS AT SCALE Q ~αS
25
Q (GeV)
10
2
10
p
1/N dn/dx
5 10
< 0.2
p
0.1 < x
H1 Data
KKP KRETZER AKK AKK (MRST2001)
Q (GeV)
10
2
10
p
1/N dn/dx
1 2 3 4 5
< 0.3
p
0.2 < x
Q (GeV)
10
2
10
p
1/N dn/dx
1 1.5 2
< 0.4
p
0.3 < x
Q (GeV)
10
2
10
p
1/N dn/dx
0.4 0.6 0.8 1
< 0.5
p
0.4 < x
Q (GeV)
10
2
10
p
1/N dn/dx
0.2 0.3 0.4
< 0.7
p
0.5 < x
Q (GeV)
10
2
10
p
1/N dn/dx
0.02 0.04 0.06
< 1.0
p
0.7 < x
NLO THEORY DOES NOT DESCRIBE THE DATA! FRAGMENTATION FUNCTIONS (KKP, KRETZER, AKK)TAKEN FROM FITS TO E+E- DATA SCALE AND PDF ERRORS SMALL SENSITIVITY TO DIFFERENT FF
26
27
KINEMATIC PHASE SPACE 2 < Q2 < 100 GeV2 0.05 < y < 0.6 0.5 < PT,K0,Λ <3.5 GeV |ηK0,Λ | < 1.3
) [GeV]
0.4 0.5 0.6
Entries per 2MeV
5000 10000 15000
H1
+
K H1 Data
) [GeV]
+
M(
1.1 1.15 1.2
Entries per MeV
1000 2000 3000 H1 +
b)
) [GeV]
1.1 1.15 1.2
Entries per MeV
1000 2000 3000 H1
a)
213,000 22,000 20,000 DOUBLE GAUSSIAN + LINEAR BACKGROUND DOUBLE GAUSSIAN + BACKGROUND
SECONDARY VERTEX
28
25% FROM THE HARD INTERACTION
λs 1/9 1/9 αs
K0
4/9 αs BR
SUPPRESSION q = 1/3, αs BRANCHING FRACTIONS FRAGMENTATION λs STRANGENESS SUPPRESSION FACTOR, λs, THE PROBABILITY OF CREATING A STRANGE QUARK COMPARED TO u OR d IN THE NON-PERTURBATIVE PROCESS EXPECT λs TO BE UNIVERSAL; ALEPH TUNE, λs = 0.286,
29
]
2
[nb/GeV
2
X)/dQ
s
e K
1 2 3 4 5 6 7 H1
H1 Data =0.3)
s=0.22)
s=0.3)
s=0.22)
s]
2
[GeV
2
Q
10
2
10 Theory / Data 0.8 1 1.2
a)
e p →
[nb/GeV]
T
X)/dp
s
e K
20 40 H1
H1 Data =0.3)
s
=0.22)
s
=0.3)
s
=0.22)
s
[GeV]
T
p
0.5 1 1.5 2 2.5 3 3.5 Theory / Data 1 1.5
c)
PS - λs ~ 0.22 CDM - λs ~ 0.3 PT SHAPE WRONG FOR ALL SIMILAR STORY FOR OTHER VARIABLES; η, XBJ, BERIT FRAME, ETC... NO ONE MODEL OR λs CAN DESCRIBE ALL DATA
]
2
[nb/GeV
2
X)/dQ
s
e K
1 2 3 4 5 6 7 H1
H1 Data CDM (CTEQ6L) CDM (GRV LO) CDM (H12000 LO)
]
2
[GeV
2
Q
10
2
10 Theory / Data 0.8 1 1.2
a)
e p →
SOME PDF DEPENDENCE CDM - λs ~ 0.3 PREFERRED
30
ep PHYSICS MORE COMPLICATED THAN e+e-, MAY CAUSE SOME OF THE DIFFERENCE TAKE RATIO OF K0 TO ALL CHARGED PARTICLES (~π) ONLY THE DIFFERENCES IN PARTICLE PRODUCTION BETWEEN ud AND s LEFT BOTH PS AND CDM SIMILAR PREDICTIONS FOR SIMILAR λs
e h X)
s
e K
0.04 0.06 0.08 0.1 0.12
H1
H1 Data =0.3)
s
=0.22)
s
=0.3)
s
=0.22)
s
]
2
[GeV
2
Q 10
2
10
Theory / Data
0.8 1 1.2
a)
→
s
e’ h X)
s
e’ K
0.04 0.06 0.08 0.1 0.12
H1
H1 Data =0.3)
s
=0.22)
s
=0.3)
s
=0.22)
s
[GeV]
T
p 0.5 1 1.5 2 2.5 3 3.5
Theory / Data
0.8 1 1.2
c)
CONSTANT FOR η, Q, XBJ STRONG DEPENDENCE ON PT, EXPECTED
31
]
2
[GeV
2
Q
10
2
10
0.1 0.2
H1
H1 Data x
10
10
10
0.1 0.2
H1
H1 Data [GeV]
T
p
0.5 1 1.5 2 2.5 3 3.5
0.1 0.2
H1
H1 Data
0.5 1
0.1 0.2
H1
H1 Data
a) b) c) d)
− Asymmetry
ALL DISTRIBUTIONS CONSISTENT WITH ZERO - BUT LIMITED ACCEPTANCE A SIGNIFICANT ASYMMETRY BETWEEN ΛΛ WOULD INDICATE THAT BARYON NUMBER WAS BEING TRANSFERRED FROM THE PROTON BEAM TO THE FINAL STATE
32
33
2000 4000 6000 8000 x 10 2 0.75 1 1.25 1.5 2000 4000 6000 8000 10000 x 10 0.75 1 1.25 1.5 2000 4000 6000 8000 10000 x 10 2 0.7 0.8 0.9 1 1.1 1.2
m(+) [GeV] entries per 25 MeV
Fit B(m) H1 Data Prel. a)
H1 Preliminary
m(+) [GeV] entries per 25 MeV
H1 Data Prel. Fit B(m) refl. K0 refl. b)
f0 f2
H1 Preliminary
m(K± ) [GeV] entries per 25 MeV
± Fit B(m) all refl. K0 signal H1 Data Prel. c) K0
H1 Preliminary
m(K+K) [GeV] entries per 2 MeV
Fit B(m) signal H1 Data Prel.
H1 Preliminary
d)
10000 15000 20000 1 1.02 1.04 1.06
F(m) = B(m) + ΣR(m) + ΣS(m)
TAGGED PHOTOPRODUCTION Q2< 0.04 GeV2 174 < W < 256 GeV PT,ρ0K*0ϕ > 0.5 GeV |η,ρ0K*0ϕ| <1.0 ρ0(770) →π+π- K*0(892)→K+/-π-/+ ϕ(1020)→K+K- QUASI-REAL PHOTON PROTON INTERACTIONS
m() [GeV] normalised entries per 25 MeV
H1 Data Prel. PYTHIA 6.2 with BEC PYTHIA 6.2 without BEC
H1 Preliminary
0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.45 0.55 0.65 0.75 0.85 0.95 1.05
BOSE-EINSTEIN CORRELATIONS <W> = 210 GeV
RELATIVISTIC BREIT-WIGNER + RESOLUTION FUNCTION
34
DAMPED POWER LAW
1 π d2σγp dp2
T dy =
A (ET0 + Ekin
T
)n
Ekin
T
=
0 + p2 T − m0
exp(−Ekin
T
/T)
T = ET0/n
UBIQUITOUS IN NATURE CLASSICAL THERMODYNAMIC ANALOGY, BOLTZMANN LIKE EXPONENTIAL
Ekin
T
small
TEMPERATURE AT WHICH HADRONISATION TAKES PLACE
Ekin
T
large
TRANSVERSE KINETIC ENERGY NORMALISATION FACTOR
ET0 = 0
POWER LAW AS EXPECTED FROM QCD IN pQCD n IS A CONVOLUTION OF PARTON DENSITIES AND PARTON PARTON CROSS SECTIONS
PRODUCTION FLAT IN RAPIDITY
35
10
10
10
1 10 10 2 10 3 10 4 10 5 1 10
pT [GeV] d2/(dydp2
T) [nb/(GeV)2]
h±, H1 Data K0
s, H1 Data
, H1 Data (D*+ + D*-)/2, H1 Data 0, H1 Data Prel. (K0+ K
0)/2, H1 Data Prel.
, H1 Data Prel.
H1 Preliminary
f(E
kin T ) =
A (ET0 + E
kin T )n
n = 6.7
PRODUCTION FLAT IN RAPIDITY
ρ0 K*0 ϕ <pt>γp <pt>pp <pt>AuAu
0.726 ± 0.021 0.811 ± 0.025 0.860 ± 0.032 0.616 ± 0.062 0.81 ± 0.14 0.82 ± 0.03 0.83 ± 0.1 1.08 ± 0.14 0.97 ± 0.02
THERMODYNAMIC PICTURE OF HADRONISATION WHERE PRIMARY PARTICLES THERMALISED DURING HADRONISATION n=6.7 TAKEN FROM PRECISE CHARGED PARTICLE DATA PARTICLES PRODUCED WITH DIFFERENT MASSES, LIFETIMES AND STRANGENESS CONTENT HAVE SAME AVERAGE TRANSVERSE KINETIC ENERGY
< pt >=
T
>2 +2 < Ekin
T
> m0
RHIC W = 200 GeV
ρ0 K*0 ϕ Tγp TPythia
0.151±0.006 0.166±0.008 0.170±0.009 0.136 0.14 0.149
36
p <W> = 210 GeV, |ylab|<1 H1 Data Prel. pp s
= 200 GeV, |y|<0.5
STAR AuAu s
STAR
R(/K0)
0.3 0.4 0.5 0.6 0.7
ENHANCED PRODUCTION OF ss QUARKONIUM STATE IN AuAu COMPARED TO pp AND γp. R(K*0/ρ0) = 0.221 ± 0.033
CROSS SECTION RATIOS
INTEGRATED OVER pt AND y R(ϕ/ρ0) = 0.078 ± 0.012 R(ϕ/K*0) = 0.354 ± 0.055 PYTHIA / PHOJET MONTE CARLOS NEED λS ~ 0.32 TO DESCRIBE THESE RATIOS INCONSISTENT WITH DIS RESULTS
37
38
M [GeV]
0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3
Entries
10 20 30 40 50 60 70 80 90 100
3
10
HERA II invariant mass
± *
K
H1 Data (Prel.)
K∗± → K0
sπ±
USE CHARGE TO MEASURE s AND s RATE, POSSIBLE SENSITIVITY TO STRANGENESS ASYMMETRY IN PROTON
]
2
[GeV
2
Q
10
2
10
]
2
[pb/GeV
2
/dQ ! d
1 10
2
10
3
10
4
10
H1 Data (Prel.) Django Rapgap X)
! *eK " cross section in DIS (ep
! *Inclusive K
H1 Preliminary HERA II
[GeV]
T
p
1 10
[pb/GeV]
T
/dp ! d
2
10
3
10
4
10
5
10
H1 Data (Prel.) Django Rapgap X)
! *eK " cross section in DIS (ep
! *Inclusive K
H1 Preliminary HERA II
5
BASIC FEATURES DESCRIBED BY MONTE CARLO MODELS
xF = 2PL/W
HADRONIC CENTRE OF MASS FRAME
F
x
0.2 0.4 0.6 0.8 1
[pb]
F
/dx ! d
2
10
3
10
4
10
5
10
H1 Data (Prel.) Django ud cb s X)
! *
eK " cross section in DIS (ep
! *
Inclusive K
H1 Preliminary HERA II
NON STRANGENESS DOMINATES HARD INTERACTION
5 < Q2< 100 GeV2
39
5 10 15 50 100 5 10 15 50 100
[GeV]
t, Jet
E Events
H1 Data 96+97 MEPS CDM QCDINS
INSTANTONS ARE NON-PERTURBATIVE FLUCTUATIONS OF THE GLUON FIELD. THEY REPRESENT TUNNELLING TRANSITIONS BETWEEN TOPOLOGICALLY NON-EQUIVALENT VACUA.
THEY ARE REQUIRED BY QCD AND THEIR CROSS SECTION CAN BE CALCULATED, UNDER CERTAIN ASSUMPTIONS, IN QCD
I
q"
I
W
2 2
q e e W s P g = P !
"
SIGNATURE- A LARGE NUMBER OF HADRONS AT HIGH TRANSVERSE ENERGY EMERGING FROM A “FIRE-BALL” LIKE TOPOLOGY. DIFFERENCES IN BACKGROUND PREDICTION LARGER THAN INSTANTONS CROSS SECTION
40
5 QUARK BOUND STATES
MOST RECENT ANALYSES AROUND THE WORLD HAVE PROVED NEGATIVE
Θ+ → K0
sp
(suuud)
50 100 150 200 250
Entries / 5 MeV
H1
2
< 100 GeV
2
20 < Q
H1 data bgr fit
1.45 1.5 1.55 1.6 1.65 1.7 1.75 1.8 20 40 60 80
95 % C.L.
)) [GeV] p p(
S
M(K [pb]
! UL
" ZEUS NA49 (uussd) Ξ0
5q → Ξ−π+ → [Λπ−]π+
Ξ0(1530)
41
M(D*p) [ GeV ]
2.9 3 3.1 3.2 3.3 3.4 3.5 3.6
Entries per 10 MeV
10 20 30 40 50 60
p
+p + D*
wrong charge D D* Monte Carlo
M(D*p) [ GeV ]
2.9 3 3.1 3.2 3.3 3.4 3.5 3.6
Entries per 10 MeV
10 20 30 40 50 60 HERA I+II data
high proton momentum
H1 Preliminary
M(D*p) [ GeV ]
2.9 3 3.1 3.2 3.3 3.4 3.5 3.6
Entries per 10 MeV
2 4 6 8 10 12 14 16 18 20
p
+p + D*
wrong charge D D* Monte Carlo
M(D*p) [ GeV ]
2.9 3 3.1 3.2 3.3 3.4 3.5 3.6
Entries per 10 MeV
2 4 6 8 10 12 14 16 18 20 HERA I data
(in HERA II phase space) high proton momentum
H1 Preliminary
H1 OBSERVED SIGNAL FOR A CHARMED PENTAQUARK IN HERAI DATA SET OTHER EXPERIMENTS LOOKED FOR IT BUT FAILED TO SEE ANYTHING NO SIGNAL OBSERVED IN HERAII !
42
f0(1710) CANNOT BE A PURE GLUEBALL, SINCE IT COUPLES TO γγ. MUST THEREFORE MIX
K0K0 FINAL STATES
K0KO SYSTEM EXPECTED TO COUPLE TO SCALAR AND TENSOR GLUEBALLS, F01720 GLUEBALL CANDIDATE FROM LATTICE CALCULATIONS.
INTERFERENCE EFFECTS INCLUDED IN FIT
43
With HERA data there is the possibility to study many different aspects of (np)QCD via particle production. Universality of fragmentation broadly supported BUT there are differences in detail when comparing to models (NLO FF , λs, string length etc...). Expect further results on strangeness, instantons, underlying event, multi parton dynamics.
44
QCD IS CLEVER BUTS ITS NOT THAT CLEVER
45
46
p
x
0.2 0.4 0.6 0.8 1
p
/dx 1/N dn
10
10 1 10
2
10
3
10
4
10
5
10
6
10
7
10
8
10
<Q> = 12.3 GeV <Q> = 14.5 GeV <Q> = 18.0 GeV <Q> = 25.0 GeV <Q> = 36.0 GeV <Q> = 58.2 GeV <Q> = 102 GeV
a)
PS
H1 Data
Q, E* (GeV)
10
2
10
p
/dx 1/N dn
10
10 1 10
2
10
3
10
4
10
H1 Data
+
e PS
range
p
x
b)
0.0 - 0.02 (x30) 0.02 - 0.05 (x5) 0.05 - 0.1 (x2) 0.1 - 0.2 0.2 - 0.3 0.3 - 0.4 0.4 - 0.5 0.5 - 0.7 0.7 - 1.0
47
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51