abstract

We study the topology of “min-bias” and hard collisions in Run 2 at the Tevatron by examining charged particle correlations. The \(\Delta \phi \) dependence of the density of charged particles and the scalar \(p_{\mathrm T}\) sum density relative to the direction of the leading jet for “leading jet” and “back-to-back” events are studied. The “jet structure” in the “underlying event” and in “min-bias” collosions is studied by defining “associated” charged particle densities that measure the number of charged particles accompanying the maximum \(p_{\mathrm T}\) charged particle in the transverse region or the maximum \(p_{\mathrm T}\) particle in the event.

abstract

The concept of parton fragmentation in QCD hard scattering phenomenology as well as NLO pQCD analysis of fragmentation functions are outlined. Hadroproduction of pions of a few GeV \(p_\perp \) is discussed through the example of recent measurements at \(\sqrt {S_{\rm RHIC}}=200\) GeV.

abstract

We give a short review about the hydrodynamic model and its application to the elliptic flow phenomena and the pion interferometry in relativistic heavy ion collisions.

abstract

Connection between the stability of quantum motion in random fields and quark confinement in QCD is investigated. The analogy between the fidelity and the Wilson loop is conjectured, and the fidelity decay rates for different types of quark motion are expressed in terms of the parameters which are commonly used in phenomenological and lattice QCD.

abstract

Hot dense matter were created at RHIC. Strange quark dynamics are both useful and important in identifying and understanding the properties of the state with partonic degree of freedom. In Au+Au collisions at 200 GeV, the value of strangeness phase space factor \(\gamma _{s}\) approaches 1 in the most central collisions. Nuclear modification factor \((R_{\rm CP})\) and elliptic flow \((v_2)\) of strange baryons (\({\mit \Lambda }+\overline {{\mit \Lambda }}\), \({\mit \Xi }^{-}+\overline {{\mit \Xi }}^{+}\), \({\mit \Omega }^{-}+\overline {{\mit \Omega }}^{+}\)) in the intermediate \(p_{\rm T}\) region of 2–5 GeV/\(c\) are consistent among them and with those of protons, indicating similar quark dynamics in baryon formation between \(s\) quarks and light \(u\), \(d\) quarks. It is consistent with a scenario of quark recombination/coalescence mechanism based on constituent quark degree of freedom in baryon formation from a nearly strange equilibrated state with high strange quark density in central Au + Au collisions at RHIC.

abstract

The main focus of the Hermes experiment is the experimental investigation of the spin structure of the nucleon. For Run II of Hermes one of the main topics is the study of the transverse spin structure of the nucleon. Using a transversely polarised hydrogen target single-spin asymmetries are measured in semi-inclusive electro-production of charged and neutral pions in deep inelastic scattering. Two different azimuthal dependences that can be related to the transversity distribution are extracted.

abstract

We review the production and flow of the identified hadrons at RHIC with main emphasis on the intermediate transverse momentum region (\(p_{\rm T} \approx 2\)–5 GeV/\(c\)). The goal is to unravel the dynamics of baryon production and resolve the anomalously large baryon yields and elliptic flow observed in the experiments.

abstract

Several puzzles about the data at high \(p_{\rm T}\) in heavy-ion collisions are listed. The resolution of them all is given in the framework of parton recombination. More specifically, it is the recombination of the soft and semi-hard shower partons that enhances the region \(3\lt p_{\rm T}\lt 9\) GeV/\(c\), and gives rise to the large \(p\)/\(\pi \) ratio in Au Au collisions. The Cronin effect can be explained in terms of final-state interaction for both \(\pi \) and \(p\). The structure of jets produced in Au Au is different from that in \(pp\) collisions. The suppression of \(R_{\rm CP}\) in forward production can also be understood by extending the same hadronization scheme at \(\eta =0\) to \(\eta \gt 0\) without the introduction of any new physics.

abstract

The color dipole formulation provides an intuitive picture of hard processes in high energy scattering. Most importantly, this approach allows one to calculate nuclear effects in a parameter-free way. I review the relation between the dipole approach and transverse momentum factorization and present numerical results for open heavy flavor production in proton–proton and proton–nucleus collisions. The cross section for heavy quark production off nuclei is known to reflect gluon shadowing, but is also affected by higher twist effects and by finite coherence length effects.

abstract

In this report, we present the measurements of open charm production at mid-rapidity in \(p+p\), \(d\)+Au, and Au+Au collisions at RHIC energies. The techniques of direct reconstruction of open charm via its hadronic decay and indirect measurements via its semileptonic decay are discussed. The beam energy dependence of total charm cross section, electron \(p_{\mathrm T}\) spectra, and their comparisons to theoretical calculations, including NLO pQCD, are presented. The electron spectra in \(p+p\), \(d\)+Au, and Au+Au collisions at \(\sqrt {s_{\mathrm {NN}}}=200\) GeV show significant variation. The open charm absolute cross section at midrapidity and its centrality dependence are compared to those of inclusive hadrons integrated over \(p_{\mathrm T}\gt 1.5\) GeV/\(c\).

abstract

A review of recent top and \(b\) physics results from the CDF and DØ Collaborations is presented.

abstract

This talk gives a brief overview of some of the CDF analyses involving charm production. New CDF triggers add a “charm factory” role for CDF and lead to huge data sets. Results on the \(J\)/\({\mit \Psi }\) cross section and charm decay rate ratios are given, along with limits on CP asymmetry and flavor-changing-neutral currents. The \(X(3872)\) object reported by the Belle Collaboration is confirmed at the Tevatron, but the charm pentaquark reported by the H1 Collaboration is not in in evidence at this time at CDF. A search for anomalies in the production of displaced jets plus a hard photon found no deviations from QCD expectations. Finally, a mention is made of the Tevatron’s improved luminosity.

abstract

Single top-quark production, via weak-interaction processes, is an important test of the standard model, potentially sensitive to new physics. However, this measurement is much more challenging at the Tevatron than originally expected. We reexamine this process and suggest new methods, using shape variables, that can supplement the methods that have been discussed previously.

abstract

In this paper, we review recent progress in the field of semileptonic decays of charm mesons, including topics on the relative branching ratio and the form factors. The comparison between the experimental form factor measurements and the lattice QCD calculations is emphasized.

abstract

Higher-order correlations have been observed as particle-density fluctuations. Approximate scaling with improving resolution provides evidence for a self-similar correlation effect. Quantum-Chromodynamics branching is a good candidate for a dynamical explanation of these correlations in \(e^+e^-\) collisions at CERN/LEP and, as expected, also of those in \(pp\) collisions at future CERN/LHC energies. However, also other sources such as identical-particle Bose–Einstein interference effects contribute.

abstract

We argue that recent NA49 results on multiparticle distributions and fluctuations, as a function of the number of participant nucleons, suggest that percolation plays an important role in particle production at high densities.

abstract

It is pointed out that the powerful statistical methods introduced by Bachelier and Mandelbrot in Economics, and those introduced by Hurst and Feder in Marine Sciences, can be readily used to examine fluctuation phenomena in hadron-production processes. Evidences for the existence of non-Gaussian stable, stationary, scale invariant distributions, fractal dimensions, and the validity of Hurst’s empirical law are presented. Since none of the observed features is directly related to the basis of the conventional physical picture, it is not clear whether (and if yes, how and why) these striking empirical regularities can be understood in the framework of the conventional picture including QCD.

abstract

A model independent method of measurement of correlations between particles belonging to close, partially overlapping hadronic systems is used by LEP collaborations to study \(e^+e^-\rightarrow W^+W^-\rightarrow \) hadrons. The strategy of the combination of the results is discussed.

abstract

The Bose–Einstein (or HBT) correlation functions are evaluated for the fractal structure of QCD jets. These correlation functions have a stretched exponential (or Lévy-stable) form. The anomalous dimension of QCD determines the Lévy index of stability, thus the running coupling constant of QCD becomes measurable with the help of two-particle Bose–Einstein correlation functions. These considerations are tested on NA22 and UA1 two-pion correlation data.

abstract

The potential for two-particles correlation studies is investigated using data collected by the HERA-B experiment. HERA-B is a fixed-target multi-particle spectrometer experiment operating at the 920 GeV HERA proton beam at DESY. The minimum bias data sample from the 2002/2003 HERA run, consisting of 200 million interactions recorded with a minimum bias trigger, provides the opportunity of determining the Bose–Einstein correlation function parameters for both pion and kaon pairs. Preliminary results, for pions, are presented.

abstract

We study effects of the event-by-event fluctuation of the initial conditions and the continuous pion emission during the whole development of the hot and dense matter formed in high-energy collisions on the two-pion interferometry. Important deviations occur, from the standard version of hydrodynamics with smooth initial conditions and a sudden freeze-out on a \(T=T_{\rm fo}\) hypersurface. Comparison with data at RHIC shows that this description can give account of the \(m_{\rm T}\) dependence of \(R_{\rm L}\) and \(R_{\rm s}\) and significantly improves \(R_{\rm o}\) with respect to the usual version.

abstract

We present preliminary two-particle correlations for unidentified hadrons in \(p\)–\(p\) collisions at \(\sqrt {s}=\)200 GeV. On two-particle transverse rapidity space \(y_{\rm t} \otimes y_{\rm t}\) two distinct regions of correlated pairs are observed: a peaked structure at low \(y_{\rm t}\) (\(p_{\rm t}\leq 0.4\) GeV/\(c\)) and a broad structure at higher \(y_{\rm t}\), where the correlation is distributed as a \(2D\) Gaussian centered at \(y_{\rm t1}=y_{\rm t2}\simeq 2.8\) (\(p_{\rm t1},p_{\rm t2} \simeq 1.2\) GeV/\(c\)). We select those regions separately, projecting correlations onto momentum-difference variables (\(\eta _{{\mit \Delta }},\phi _{{\mit \Delta }}\)), and observe structures interpretable in the context of string and parton fragmentations from soft and semi-hard components of \(p\)–\(p\) collisions.

abstract

A brief review of jet physics is presented with an emphasis upon open theoretical problems (non-perturbative domain; hadronisation and confinement) and new phenomena (hadroproduction in heavy ion collisions).

abstract

We present recently defined jet-observables for hadron–hadron dijet production, which are designed to reconcile the seemingly conflicting theoretical requirement of globalness, which makes it possible to resume them (automatically) at NLL accuracy and the limited experimental reach of detectors, so that they are measurable at the Tevatron and at the LHC.

abstract

Resummation in QCD provides insight into the evolution of final state jets from short to long distances, and of accompanying interjet radiation. Applications to event shapes, including the recently-proposed angularities, suggest experimental tests of the interrelations between weak- and strong-coupling dynamics.

abstract

I discuss some recent development of Monte Carlo event generators and point out some problems. Starting with the issue of combining matrix element generators and parton shower algorithms, I will continue with discussing the problems associated with describing small-\(x\) final states and discuss some recent model developments for describing multiple partonic scatterings and underlying events in hadron collisions. Finally I will briefly present the ThePEG project of creating a general platform in C++ for implementing Monte Carlo event generators.

abstract

A description of the jet finding algorithms used in the CDF and DØ experiments in Run II is given.

abstract

The DØ and CDF experiments at Fermi National Accelerator Laboratory’s Tevatron collider have each amassed a significant amount of jet events, leading to new results that test the predictions of perturbative Quantum Chromodynamics. Several recent jet physics results are presented, along with a discussion of the prospects for other tests in the coming years.

abstract

Presented here are the recent Run II results on the inclusive cross section for \(W\) plus \(\geq n\) jet(s) (JetClu \(R=0.4\)). These cross sections are compared with Run I data and their ratios are measured for inclusive jet multiplicity for \(n = 0\) to 4. The leading order QCD predictions using ALPGEN + HERWIG are compared with the data. Also shown are the comparisons of Diphoton QCD production with next-to-leading order QCD predictions\(\colon \) DIPHOX and ResBos. Finally, the \(\gamma +b\) and \(\gamma +c\) cross sections are presented as a function of photon \(E_{\rm T}\).

abstract

Recent results on fragmentation obtained by the LEP experiments are discussed centering on the comparison of gluon and quark fragmentation.

abstract

Recent results from jet production in deep inelastic \(ep\) scattering to investigate parton dynamics at low \(x\) are reviewed. The results on jet production in deep inelastic scattering and photoproduction used to test perturbative QCD are discussed and the values of \(\alpha _{\mathrm s}(M_Z)\) extracted from a QCD analysis of the data are presented.

abstract

Presented are the latest results on jet fragmentation studies carried out by the CDF Collaboration. Charged particle multiplicities and momentum distributions are measured for quark and gluon jets. The multiplicities are compared to pQCD calculations and earlier results from \(e^+ e^-\) colliders. Jet shapes for a broad range of jet transverse momenta are measured and compared to Pythia and Herwig Monte Carlo event generator predictions.

abstract

Ultra-relativistic heavy ion collisions at RHIC and the LHC open exciting new possibilities for jet physics studies in the presence of hot and dense nuclear matter. Recent theoretical advances in understanding the QCD multi-parton dynamics provide a good description of the quenching in the single and double inclusive high-\(p_{\rm T}\) hadron spectra. Measurement of the redistribution of the lost energy and the corresponding increase in the soft hadron multiplicities is the next critical step in elucidating the modification of the jet properties in the nuclear environment.

abstract

Prospects for jet physics at the CERN large hadron collider are examined. Jets will play an important role in planned searches for Higgs and supersymmetry as well as the search for other new phenomena.

abstract

Kilometer-scale neutrino detectors such as IceCube are discovery instruments covering nuclear and particle physics, cosmology and astronomy. Examples of their multidisciplinary missions include the search for the particle nature of dark matter and for additional small dimensions of space. In the end, their conceptual design is very much anchored to the observational fact that Nature accelerates protons and photons to energies in excess of \(10^{20}\) and \(10^{13}\) eV, respectively. The cosmic ray connection sets the scale of cosmic neutrino fluxes. In this context, we discuss the first results of the completed AMANDA detector and the reach of its extension, IceCube. Similar experiments are under construction in the Mediterranean. Neutrino astronomy is also expanding in new directions with efforts to detect air showers, acoustic and radio signals initiated by super-EeV neutrinos.

abstract

In this talk I review how to identify cosmic ray accelerators that are high energy neutrino emitters. I also delineate the prospects for a new multi-particle astronomy: neutrons as directional pointers + antineutrinos as inheritors of directionality.

abstract

ANTARES is a project aiming at the operation of an underwater detector at a depth of 2.5 km close to Toulon in the South of France. The detector is expected to be completed at the beginning of 2007. The main purpose of the experiment is the detection of high energy neutrinos produced in astrophysical sources. Being weakly interacting, neutrinos could potentially be more powerful messengers of the universe compared to photons, but their detection is challenging. The technique employs phototubes to detect the arrival time and the amplitude of photons emitted by neutrino charged secondaries due to the Cherenkov effect. ANTARES will contribute significantly in the field of neutrino astronomy, observing the Galactic Centre with unprecedented pointing capabilities.

abstract

In this talk, we discuss issues relevant to the detections of Earth-skimming/mountain-penetrating tau neutrinos. We first argue that there are non-negligible astrophysical tau neutrino fluxes due to neutrino flavor oscillations. We then discuss the rationale for detecting Earth-skimming and mountain-penetrating tau neutrinos. The \(\nu _{\tau }\to \tau \) conversion efficiencies and the tau-lepton event rate are presented.

abstract

This is an overview of the results from the first 3 years of RHIC experiments. RHIC is a collider built to accelerate nuclei to center of mass energies of 200 GeV per nucleon for the study of QCD in bulk systems. The most important result so far is the observation of the suppression of high \(p_{\rm T}\) hadrons in central Au–Au collisions followed by the subsequent null experiment where the same suppression was not seen in deuteron–Au collisions. The observed suppression is a final state effect in which a large amount of energy is lost by the fast parton as it penetrates the medium. This observation, together with measurements of the elliptic flow, leads to the conclusion that the energy density reached is at least 10 times that of a normal nucleon. The simplest and most economical explanation of these phenomenon is that the system is a dense, locally thermalized system of unscreened color charges.

abstract

In the recent years we have seen a lot of activity around systems and experiments, like DIS at HERA or the heavy-ion experiments at RHIC, involving a large number of partons due to the high energy and/or the high number of participants of those experiments. The main problem in this regime is that of the high parton densities. In fact, in most of the models of multiparticle production, two contributions to the multiplicity are considered: one proportional to the number of participant nucleons, \(N_{\rm part}\), and a second one proportional to the number of collisions, \(N_{\rm part}^{4/3}\). In order to get the right multiplicities at RHIC it is necessary to lower the second contribution. A possible mechanism for this is the saturation. Here, I am going to review the saturation of parton densities in the initial state, in two different frameworks: the Colour Glass Condensate and the string clustering.

abstract

In this talk I discuss recent results on elliptic flow in Au+Au collisions at RHIC and how these results help us to understand the properties and evolution dynamics of the system created in such collisions. In particular, I discuss if and how the elliptic flow results obtained at RHIC indicate the system thermalization, deconfinement, and how much it tells us about the hadronization process.

abstract

We briefly report on the status of RHIC operations and summarize the rapidly developing measurements of parton propagation in dense QCD matter. These measurements are consistent with expectations of induced gluon radiation as the hard scattered parton traverses a dense colored medium.

abstract

Particle production in central Pb+Pb collisions was studied with the NA49 large acceptance spectrometer at the CERN SPS at beam energies of 20, 30, 40, 80, and 158 GeV per nucleon. A change of the energy dependence is observed around 30\(A\) GeV for the yields of pions and strange particles as well as for the shapes of the transverse mass spectra. At present only a reaction scenario with onset of deconfinement is able to reproduce the measurements.

abstract

We evaluate the Cronin effect in \(pA\) collisions at the CERN LHC and at RHIC in the framework of Glauber-eikonal model of initial state multiparton interactions. Taking carefully into account all kinematical constraints of each multi-parton interaction process we obtain a softening of the spectrum of produced partons, improving in this way the agreement of the model with the recent measurements of \(\pi ^0\) production in \(d+\)Au collisions at \(\sqrt s=200\,A\)GeV.

abstract

A systematic search for observables associated with the critical sector of QCD is attempted in view of the progress made recently in lattice QCD regarding the existence and the location of a critical endpoint in the phase diagram of the theory. Our search is necessarily oriented towards multiparticle dynamics in collisions of nuclei and in particular towards the \(\sigma \)-mode in multipion production where critical fluctuations are expected to occur. The predictions of critical QCD are incorporated in a Monte Carlo simulation of critical events and the domain in the vicinity of the endpoint, where critical fluctuations prevail, is examined on the basis of the Ginzburg criterion. The relevance of our results for measurements in the experiments with nuclei is also discussed.

abstract

The existence of a Hückel–Debye color screening is often proposed as a signal of the presence of a QCD plasma. Here the particular case is examined where the quark density is largely dominant over the gluon density. In this case the two body correlation shows a spatial decay like \( \exp [-ar^{2/3}]\) /\(r\) to be compared with the usual electric case \(\exp [-ar]\) /\(r\). The usual electrodynamical case is rapidly re-examined in order to compare it with the chromodynamical case.

abstract

The phenomena of diffractive interactions are briefly introduced. Basic ideas for theoretical descriptions are discussed and recent results on the experimental side with interpretations from the theoretical side are presented.

abstract

We present the data on diffractive scattering in electron–proton reactions at HERA and review the analysis of these data in terms of diffractive parton distribution functions. From these a clear picture of the partonic structure of diffractive exchange emerges. The basis of the analysis is the factorization property of diffractive exchange, which is subjected to experimental tests using deep-inelastic diffractive charm and jet production, as well as photoproduction of jets.

abstract

It is usually assumed — following the parton model — that the leading-twist structure functions measured in deep inelastic lepton–proton scattering are simply the probability distributions for finding quarks and gluons in the target nucleon. In fact, gluon exchange between the outgoing quarks and the target spectators effects the leading-twist structure functions in a profound way, leading to diffractive leptoproduction processes, shadowing and antishadowing of nuclear structure functions, and target spin asymmetries, physics not incorporated in the light-front wavefunctions of the target computed in isolation. In particular, final-state interactions from gluon exchange lead to single-spin asymmetries in semi-inclusive deep inelastic lepton–proton scattering which are not power-law suppressed in the Bjorken limit. The shadowing and antishadowing of nuclear structure functions in the Gribov–Glauber picture is due respectively to the destructive and constructive interference of amplitudes arising from the multiple-scattering of quarks in the nucleus. The effective quark–nucleon scattering amplitude includes Pomeron and Odderon contributions from multi-gluon exchange as well as Reggeon quark-exchange contributions. Part of the anomalous NuTeV result for \(\sin ^2\theta _{\rm W}\) could be due to the non-universality of nuclear antishadowing for charged and neutral currents. Detailed measurements of the nuclear dependence of individual quark structure functions are thus needed to establish the distinctive phenomenology of shadowing and antishadowing and to make the NuTeV results definitive. I also discuss diffraction dissociation as a tool for resolving hadron substructure Fock state by Fock state and for producing leading heavy quark systems.

abstract

We review the evidence for saturation seen at HERA, and we discuss a few theoretical aspects of saturation in deep inelastic electron proton scattering.

abstract

We report recent results on diffraction from the CDF experiment at the Fermilab Tevatron \({\bar p}p\) collider. In events with multiple rapidity gaps, we find that if a single gap survives, e.g. is not killed by products of interactions between spectator partons, any additional gaps survive as well. Diffractive structure functions are studied in single-diffractive and double-pomeron-exchange (DPE) dijet production. Exclusive production of dijets and of \(\chi _{ c}^0\) in DPE have been studied as benchmark processes for exclusive Higgs production at the LHC.

abstract

The status and future prospects of low \(x\) physics at HERA are presented.

abstract

A Very Forward Proton Spectrometer (VFPS) has been installed in the proton beam line of the H1 experiment. This device, located at 220 m downstream of the interaction point, is based on the Roman Pot technique and consists of two stations in the cold section of the proton beam line. We discuss the major physics issues which can be addressed with these forward proton taggers.

abstract

Experimental results on soft and hard diffractive processes obtained by the CDF Collaboration in \(\bar pp\) interactions are examined with emphasis on regularities that point to QCD aspects of hadronic diffraction. Data are interpreted in a phenomenological approach in which diffractive cross sections are related to the underlying inclusive parton distribution functions of the nucleon. In this approach, diffraction appears to be mediated by the exchange of low-\(x\) partons from the quark/gluon sea of the interacting nucleons subject to color constraints.

abstract

If electroweak symmetry breaking is a consequence of color sextet quark chiral symmetry breaking, dramatic, large cross-section, effects are to be expected at the LHC — with the pomeron playing a prominent role. The symmetry breaking is tied to a special solution of QCD which can be constructed, at high-energy, via the chiral anomaly and reggeon diagrams. There is confinement and chiral symmetry breaking, but physical states contain both quarks and a universal, anomalous, wee gluon component. A variety of Cosmic Ray effects could be supporting evidence, including the knee in the spectrum and the ultra-high energy events. The sextet neutron should be stable and is a natural dark matter candidate. A large \(E_{\rm T}\) jet excess at Fermilab, and large \(x\) and \(Q^2\) events at HERA, would be supporting accelerator evidence. Further evidence, including diffractive-related vector boson pair production and top quark related phenomena, could be seen at Fermilab as data is accumulated.

abstract

We provide a brief review for the motivation of Maldecena duality conjecture, leading to the calculation for the glueball spectrum and the Pomeron intercept in the strong coupling limit. We next turns to the question of hard scattering. Using Maldacena’s gauge/string duality, a unified description is provided for both the soft and the hard Pomeron in the strong coupling limit.

abstract

The effects of energy conservation and saturation are studied in the coordinate space dipole formulation for QCD cascades. Preliminary results for dipole–dipole and dipole–nucleus scattering are presented. Very large effects are obtained from energy conservation, corresponding to a factor \(\sim 10\) in the cross section and \(\sim 3\) in \(\lambda _{\mathrm {eff}}\). Some results on the gluon fusion process \(g\!+\!g\rightarrow g\) are also presented.

abstract

We discuss general properties of the Color Glass Condensate. We show that predictions for particle production in \(p(d)A\) and \(AA\) collisions derived from these properties are in agreement with data collected at RHIC.

abstract

The physics underlying the fall and eventual rise in various total cross-sections at high energies has been investigated over a decade using a model based on the Bloch–Nordsieck resummation in QCD. Here a brief review of our latest results is presented and comparison made with experimental data on \(pp\), \(\gamma \) proton and \(\gamma \gamma \) total cross-sections.

abstract

A non-perturbative approach to the calculation of generalized parton distributions (GPD) through their relation to deeply virtual Compton scattering (DVCS) and vector meson photoproduction is suggested. In the first approximation, GPDs are proportional to the imaginary part of the DVCS amplitude. A model for DVCS, developed earlier in the framework of the analytic \(S\)-matrix and incorporating duality between resonances and Regge behavior, is used for this purpose. Furthermore, a bootstrap procedure is suggested in which this GPD is used as an input in the handbag diagram, whose convolution with the perturbative kernel (loop diagram) results in the DVCS amplitude to be reconstructed from the analytic \(S\)-matrix theory and/or the experiment.

abstract

A sum rule is derived for elastic scattering of hadrons at high energies which is in good agreement with experimental data on \(p\bar {p}\) available upto the maximum energy \(\sqrt {s} = 2\) TeV. Physically, our sum rule reflects the way unitarity correlates and limits how large the elastic amplitude can be as a function of energy to how fast it decreases as a function of the momentum transfer. The universality of our result is justified through our earlier result on equipartition of quark and glue momenta obtained from the virial theorem for massless quarks and the Wilson conjecture.

abstract

After an introduction on possible scenarios in the TeV energy region in \(pp\) collisions, extrapolated from the knowledge of the GeV energy region, attention is focused on the onset of a third class of events, harder than the semi-hard and soft ones identified at SpS and Tevatron. The expected features and signatures in multiplicity fluctuations, forward–backward correlations and collision energy density are discussed.

abstract

We summarize results presented at this conference with special emphasis on hard processes with jets and heavy quarks, soft particle production, small \(x\) structure functions and diffraction as well as heavy ion collisions and quark gluon plasma.