Implication of the impact picture on multiplicity,inclusive distribution,and production processes

We predict that both the average multiplicity and the inclusive distribution for pionization products increase like a positive power of s times a power of 1ns. Thus scaling is strongly violated. An experiment involving a fragmentation product is proposed.     

Two-component description of inclusive correlations for a fixed prong number

It is pointed out that the two-component model of particle production can explain the observed structures in the correlation function of pairs of negative pions as a function of rapidity difference for a fixed prong number. It is argued that as the prong number increases this correlation function should become zero or negative at $\text{δy ? 0}$.     

Size of polarization in inclusive processes

We study polarization in inclusive processes in the beam fragmentation region in the framework of a simple Regge-cut model. We obtain predictions for the dependence on the kinematic variables, and we estimate the magnitude of polarization.     

A path integral approach to inclusive processes

The single-particle inclusive differential cross-section for a reaction is written as the imaginary part of a correlation function in a forward scattering amplitude for in a modified effective theory. In this modified theory the interaction Hamiltonian equals in the original theory up to a certain time. Then there is a sign change and becomes nonlocal. This is worked out in detail for scalar field models and for QED plus the abelian gluon model. A suitable path integral for direct calculations of inclusive cross sections is presented. Received: 8 March 2000 / Published online: 6 July 2000     

Applications of Mueller theory of two-particle inclusive processes

Assuming factorization, and extracting inclusive Reggeon vertices from one-particle inclusive data, we predict Regge corrections to scaling for several two-particle inclusive processes. The data on p + P → π^? + π^? + X, K⁺ + p → π^? + π^? + X, K^? + p → π⁺ + π^? + X, and π⁺ + p → π^? + π^? + X agree with our predictions.     

Effects of the inclusive dipole-pomeron to exclusive processes

The consequences of the inclusive dipole-Pomeron for the exclusive processes are investigated. In the weak coupling limit a two component picture for the production mechanism is obtained and self-consistency of the inclusive Pomeron dipole is found.     

Regge behaviour for inclusive annihilation and decay processes

By exploiting annihilation processes it is shown that inclusive experiments are also relevant at low energies, if duality holds.     

Deep-inelastic one-particle inclusive processes in the parton model

We study the processes e + N → e′ + h + anything, e⁺ + e^? → h + anything, within the parton model of Landshoff, Polkinghorne and Short. Definite and peculiar predictions are obtained, also common to the Drell, Levy and Yan cut-off theory and to the λφ³ ladder model. These predictions can be summarized as follows: (i) in the photon fragmentation region the cross section factorizes after integration over transverse momentum of h; (ii) in the target fragmentation region Regge behaviour, valid at large ω, gives rise to double Regge exchange for small values of the Feynman variable y, but only up to $\text{y ??1/ω}$; (iii) the structure functions vanish at y = 0; (iv) total multiplicities in the first process increase like 1n ω for large ω, and in the second reach a finite limit at large q².In the case where only one SU(3) multiplet of partons is present (as in the quark parton model) unique relations, valid in the limit of exact SU(3), are found between the cross section and multiplicities in the first process and the analogous quantities for the forward region of the second process.     

Analytic representation of the six-point function and inclusive processes

A new representation is proposed for the N-point retarded function defined as the Fourier transform of the matrix element between incoming states of the R product of two operators. Locality, crossing and normal cut structure in the invariant variables containing the Fourier vector are correctly incorporated in this representation and an explicit expression for the spectral function can be given. The case N = 6 is discussed in detail and structure functions for deep inelastic as well as purely hadronic inclusive processes are obtained from the representation.     

Observation of inclusive η production in ee annihilation at CM energies of 34 GeV

The inclusive production of η mesons at CM energies around 34 GeV has been studied for e⁺e⁻ annihilation into hadrons. The average number of η-mesons per event is found to be 0.72 ± 0.10 (stat.) ± 0.18 (syst.). The abundance of η's is studied as a function of event shape parameters and it is compared to the corresponding π⁰ rates.     

Models for high-energy inclusive processes and screening in deuterium

The screening correction to the high energy (p_lab > 10 GeV/c) elastic hadron-deuteron scattering amplitude is discussed. It is found that the correction cannot completely be calculated using as input only the data for cross sections of inclusive reactions on free nucleons. Nevertheless measurements of high energy screening corrections provide sensitive tests for models of inclusive processes. In particular elastic screening does not dominate over the inelastic screening if, as indicated by recent fits, the triple pomeron coupling does not vanish for three mass-zero pomerons. If this is the case, the theory of high energy elastic scattering on heavier nuclei would have to be reconsidered. The discussion is illustrated by a numerical calculation for elastic πd scattering in the 10GeV–2000 GeV energy range.     

Mechanism of single-spin asymmetries generation in the inclusive hadron processes

We discuss a nonperturbative mechanism for generation of the single-spin asymmetries in hadron interactions. It is based on the chiral quark model combined with unitarity and impact parameter picture and provides explanation for the experimental regularities observed under the measurements of the spin asymmetries.     

Bloch-nordsieck violating electroweak corrections to inclusive TeV scale hard processes

We point out that, since the colliders' initial states ( e(+)e(-),pp, p&pmacr;,ellipsis) carry a definite non-Abelian flavor, electroweak radiative corrections to inclusive hard cross sections at the TeV scale are affected by peculiar Bloch-Nordsieck violating double logs. We recall the setup of soft cancellation theorems, and we analyze the magnitude of the noncanceling terms in the example of electron-positron annihilation into hadrons.     

Particle momentum cut-off in inclusive processes in the region of large angles

It is shown that analyticity and unitarity lead to logarithmic cut-off of particle momentum detected in binary inclusive process in the region of large angles.     

Average nonlinear duality and the Pomeron for two-body and inclusive processes

A simple scheme combining duality with unitarity is applied to exotic ππ and π-Reggeized-? scattering. The resulting ??P triple-Regge vertex is in agreement with recent fits to inclusive cross sections. An extension to nonexotic channels is also discussed.     

Amplitude analysis and geometrical picture for Δ production processes

In this paper, a complete amplitude analysis is performed to obtain the double flip ? and A₂ contributions. As suggested by the geometrical picture the non-flip and the flip amplitudes are assumed to be identical to the ones already determined from πN and KN reactions up to t-independent real constants. Evidence for the validity of this assumption is given; SU(3) prediction works quite well with the experimental data on KN→KΔ processes.     

Unified picture for single transverse-spin asymmetries in hard-scattering processes

Using lepton-pair production in hadron-hadron collisions as an example, we explore the relation between two well-known mechanisms for single-transverse-spin asymmetries in hard processes: twist-three quark-gluon correlations when the pair's transverse momentum is large, q perpendicular > Lambda QCD, and time-reversal-odd and transverse-momentum-dependent parton distributions when q perpendicular is much less than the pair's mass. We find that, although the two mechanisms each have their own domain of validity, they describe the same physics in the kinematic region where they overlap. This unifies the two mechanisms and imposes an important constraint on phenomenological studies.     

Study of inclusive baryon-antibaryon pair production of p or Λ in two-photon processes

Inclusive baryon-antibaryon pair production was studied in two-photon events which were collected at the e ⁺ e ^? collider TRISTAN, and correspond to an integrated luminosity of 303 pb^t?1. Correlations between a baryon and an antibaryon were studied for their flavors (p or Λ) and their momentum vectors. The experimental results were compared with the expectations from a jet-fragmentation Monte Carlo simulation. We have found that although the ratios of the cross sections of different baryon-flavor combinations are consistent with the Monte Carlo expectations, the cross section shows an excess over the Monte Carlo expectation in a low invariant-mass region of final-state particles at large angles, that indicates a significant contribution from higher-order QCD or non-perturbative effects. The experimental data show no narrow azimuthal-angle correlation, which is expected from a jet-fragmentation Monte Carlo. A search for exclusive Λ pair production has also been made. We have no candidates and have obtained the upper limit for the cross section.     

Predictions for all processes ee → fermions + γ

The complete matrix elements for e⁺e⁻ → 4 and e⁺e⁻ → 4fγy are calculated in the Electroweak Standard Model for polarized massless fermions. The matrix elements for all final states are reduced to a few compact generic functions. Monte Carlo generators for e⁺e⁻ → 4f and e⁺e⁻ → 4fγ are constructed. We compare different treatments of the finite widths of the electroweak gauge bosons; in particular, we include a scheme with a complex gauge-boson mass that obeys all Ward identities. The detailed discussion of numerical results comprises integrated cross sections as well as photon-energy distributions for all different final states.