Slide 1

Report
HSQCD 2004
DGLAP
BFKL
DPP
GLR
Alan Martin (Durham)
Repino, St. Petersburg
18-22 May, 2004
Klempt
Glueballs, hybrids, pentaquarks
not a glueball
Klempt
Pentaquarks
Several expts see an exotic B=1, S=1
baryon resonance in K+n or K0p channel
Qs(1530) with narrow width G<10 MeV
The chiral soliton model (cSM) predicted Qs(1530)
with G<15 MeV, JP=(1/2)+ in a 10 of SU(3)f
Praszalowicz(1987), Diakonov,Petrov,Polyakov(1997)
Qs(1530)
seen by many
expts in K+n, K0p
N
S
X-NA49 see X(1860) which is
not seen by ZEUS & WA89
X
Popov
HERMES
Hyarapetian
but is Qs(1530)
seen by H1 ??
Kubantsev
1.5 MeV now expected from cSM --- Petrov
Petrov
Bag model fails for Q+(uudds)
Need new degree of freedom:
diquark ? -------CQM
Jaffe-Wilczek (ud)2 s
Karliner-Lipkin (ud)(uds)
…..but needs diquark in P-wave, many problems,
always predicts too heavy Q+ e.g. Narodetskii
p is lightest degree of freedom ----- cSM
Polyakov
is the N*(1710) in the 10 ?
considers mixing with octet
gpp* / gnn* ~ 0 by U-spin
G(N*) ~ 10-20 MeV
Qs(1530)
pN 2 MeV
pD 5 MeV
hN 3 MeV
N
S
X
pN PWA: N* could be P11(1680 or 1730)
Petrov considers
mixing with the
Roper octet
Klempt
1577 ?
cSM predicts 27 with I=1 KN multiplet -- but K+p partner not seen
Buschhorn
H1 see Qc
which is not seen by ZEUS ?
bb prod: latest data and theory in satisfactory agreement
Hadron spectroscopy is on the boil.
Changes almost daily.
Very exciting and experimentally confusing.
Rostovsev
low x
Fixed target DIS ep, ed, nN; D-Yan, W asym, Tevatron jets
HERA ep
global DGLAP parton analyses CTEQ, MRST
analyses to selected data sets Botje, Alekhin, ZEUS, H1…
Expect small x processes
to be driven by the gluon.
Surprise  at v.low scales
appear to be dominated by
by singlet sea quarks 
valence-like or -ve gluon !
Sea quarks & gluons not
(perturbatively) connected.
x
F2 versus x
1993
(Lum=20 nb-1)
Now
BFKL
confinement
Regge
ln 1/x
DGLAP
ln Q2
HERA has opened up the small x domain
• how large is the DGLAP domain ?
• are BFKL (log 1/x) effects evident ?
• is there any evidence of absorptive corrections,
or even parton saturation ?
• HERA observes diffractive DIS (at ~10% of DIS).
What role does it play ?
• what would we like HERA to measure now ?
CTEQ gluon
Q2=5
compared to
MRST error band
Q2=100
Parton uncertainties due to stat/sym errors of data fitted
Other uncertainties include
selection of data fitted; choice of
x,Q2,W2
cuts
Kotikov
Theoretical uncertainties
higher-order DGLAP NLO, NNLO…Moch,Vermaseren,Vogt
asln(1/x) and asln(1-x) effects
absorptive corrections from parton recombination
residual higher-twist effects
QED effects
Uncertainties due to input assumptions
isospin-violating effects MRST
s not equal to s
CTEQ
heavy-target corrections
choice of input parametrization
no NuTeV sin2q anomaly
Alwall
MRST NNLO
suggests W or Z prod. can be
be used as a luminosity monitor
at the Tevatron (& LHC)
Kataev
IG =
=
Gottfried sum rule in the large Nc limit
(dx/x) (F2mp – F2mn) = 0.235 +/- 0.026 expt.
1/3
-
2/3
valence:
pert. corr. small,
higher twist small
as/Nc2
dx (d – u)
non-pert asymmetry
of sea.
what happens as x0?
(cSM)
(i)checks from Adler SR.
(ii) 3-loop anom. dim. of
MVV (NNLO) confirms
colour structure
Experimental ways to determine the gluon
• FL
most direct x ~ 10-4 - 10-3
• Prompt photon
data (WA70,E706) and theory problems
• Tevatron jets
x ~ 0.07 – 0.5
• HERA jets
(ZEUS)
x ~ 0.01 - 0.1
• Diffractive J/y
at HERA
g2
(+ momentum sum rule)
x ~ 10-3
need to improve theory
Inclusive jets
Zeitnitz
Top quark cross section
Run I
Run II
Savin &
Rostovtsev
inclusive jet
helps pin down
gluon at x~0.1
3 jets/2 jets
FL
Q2=10
Q2=5
Extremely valuable if
HERA could measure
FL with sufficient
precision --- to pin
down the low x gluon
Data are Klein’s
simulation based
on runs at Ep =
400,465,575,920
GeV.
Q2=20
Thorne
Q2=40
Stirling
Higgs
DGLAP
ln 1/x resum ?
abs. corr. ?
Lipatov
What happens to the Pomeron traj. at high temp.?
Remarkably -- nothing happens for fixed as.
-- result of conformal inv. of the original theory.
Running as destroys inv. – no exact solution –
expect some change
May be possible to establish relation between
BFKL and string dynamics –
dimensions of space-time = no. of t ch. gluons?
Gluon kt distribution in resummed NLL BFKL
Gluon kt along evolution
chain --- find that
NLL BFKL and DGLAP
v.similar
Important since
underlying event
might have masked
New Physics signals
at LHC.
Ryskin
Final kt=30 GeV at y=ln(1/x)=8
LO BFKL
DGLAP, DLLA
NLL BFKL
y=4
Monte Carlos OK
y=6
y=2
Diffractive DIS data
Mastroberardino
Schildknecht:
Also describes F2, F2D,
vector meson prod.
well, using dipole
approach with GVMD,
incorporating saturation
Original Golec-Biernat, Wusthoff fit
Include charm.
Relate to xg &
evolve in Q2
+Bartels,Kowalski
Is it saturation or
confinement ?
mq=0
mq=140 MeV
There are other
dipole fits without
saturation
e.g. Forshaw,
Kerley & Shaw.
Saturation
No definitive experimental evidence
Much theoretical activity ----BK, JIMWLK,…equations
A glimpse…
Rostovsev
Equivalent approaches
p rest frame / fast dipole
fast p / slow dipole
bare dipole
g wave
fn.
evolved p
wave fn.
(cgc)
Balitsky Kovchegov eq.
Lublinsky explained this much
better
leads to
Jalilan Marian, Iancu, McLerran,
Weigert, Leonidov, Kovner eq.
Two progress reports:
Fadin
is proving that gluon Reggeization is valid at NLO BFKL
Checking the consistency of bootstrap relations, s ch.
unitarity and Reggeization for production amplitudes.
Bartels
is relating the BK equation to Reggeon field theory
Remarkable simplifications from Mobius invariance
Saturation momentum Qs(x) in NLL BFKL ~ DGLAP
Qs
Ryskin
2
LO BFKL
unreliable,
BK,JIMWLK
eqs. ?!
x0/x
x0 defined by
Qs(x0)=1 GeV
Nikolaev
Saturation effects in nuclei.
Diffractive DIS is about 50% in nuclei.
Collective nuclear glue (nuclear Pomeron) is a
good idea but destroys kT factorization.
Also fan diagrams no longer sufficient.
Diffractive DIS data
Mastroberardino
Mastroberardino
Mastroberardino
Mastroberardino
ln Q2
higher
twist
Bartels,Ellis,
Kowalski & Wusthoff
base parametrization
on these forms
Contribution of diffractive F2 to inclusive F2
Apply the AGK cutting rules to
Ryskin
contrib.
AGK in QCD: Bartels & Ryskin
Im Tel ~ stot
DF2abs ~ - F2D
In pQCD,
negative
is a cut, not a pole
(~Glauber shadowing)
Lipatov
has a continuous no. of compts of different size, r~1/m
For each compt., DGLAP evol. of F2D(x,Q2,m2) starts
from m  Q
provided it is large enough
Ryskin
Ryskin
Input ~ MRST2001
Ryskin
Ryskin
xg, xS  const
Need Q2  Q2+1
mimics power corr.
rapidity gap survival
factor
S2 ~ 0.1
HERA
g*
Survival factors calc. from
2-ch eikonal model based
on multi-Pom. exchange &
s channel unitarity KKMR
S2 ~ 1
Mastroberardino
Diffractive photoproduction of dijets:
direct compt. S2 ~ 1
resolved compt. (hadron-like) S2 ~ 0.34
NLO analysis by
Klasen & Kramer,-good agreement
with prelim. H1 data
Note in LO analysis,
data would prefer
S2 ~ 1 for resolved
Exclusive diffractive Higgs signal
pp  p+H+p
Khoze
Advantages: 2 indep. MH det.
1. missing mass to proton
taggers (DM~1 GeV)
2. bb decay (DM~10 GeV)
Higgs
S2 = 0.026
bb backgd v.suppressed
by Jz=0 selection rule
For a 120 GeV (SM) Higgs
at the LHC (L=30 fb-1)
11 events / 4 background
For MSSM
with tanb~50, mA~130 GeV
70 events / 3 background
Khoze
5s signal at LHC
30 fb-1
300 fb-1
Kim, Schlein
Higgs via single Pomeron exchange
Predicted much larger signal, but
---need to study of background,
---include evolution from Q2=50 GeV2 (UA8) up to
Q2=104 GeV2
Amarian
Semi-inclusive ep  epX
HERMES
Sidorov
Sidorov
Ochs
Ng/Nq = CF/CA = 9/4 --
naïve
MLLA -- better agreement with e+e- data
Full calculation – excellent agreement
L parameter determined from multiplicity
Pivovarov
Calculated the B parameter at NLO --- three loop
non-factorising massive Feynman graph
B = 1 + 0.095 - 0.05
pert. nonpert.
Apologies omitting for so many excellent contributions
There are so many crucial measurements still to
be done, and unless the correct action is set into
motion soon, time will run out for HERA --while the physics potential of the machine is still
coming to its prime.
Buschhorn
Very special thanks to
Petersburg Nuclear Physics Institute
Petersburg branch of the RAS
Petersburg State University
Fock Institute of Physics
Staff of the Baltiets Hotel
Assistants
Pavel Yakimov
Julia Grebenyuk
Nastya Grebenyuk
Sergey Anufriev
Sergey Afonin
Photographer
Tatiana Potapova
Foreign department
Tatiana Bondarenko
Natalia Nikitina
Drivers
Sergey Zvonovsky
Eduard Patsyukov
Dima Dzyubchuk
Social Programme
Lyudmila Kolesnikova
Victor Gordeev
Victor Kim
Lev Lipatov
Secretariat
Galina Stepanova
Zoya Gaditskaya
Lidia Rusinova
Tatiana Gordeeva
…and to ALL the participants for making this such
a productive and enjoyable meeting
…and so on to HSQCD 2005

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