Mean net charge of hadron jets

The behaviour of the mean net charge for the simplen-quark distribution function of hadron jets is discussed. The behaviour of the mean net charge of proton jet treated as quark-diquark system and threequark system is shown.     

Structure of hadron beam jets at smallP T

A dynamical model of hadron beam jets in high energy hadron-hadron collisions at smallp _T is presented on the basis of the assumptions that (i) a meson is composed of a constituent quarkq and an antiquark \(\bar q\) , while a baryon is composed ofq andqq (diquark), and (ii) mesons, baryons and antibaryons are emitted via the cascade mechanism ofq andqq. These assumptions lead to a simple treatment of meson, baryon and antibaryon productions from hardon beam jets. A set of coupled integral equations for \(\bar q\) andqq fragmentation functions is solved in moment space and converted into the longitudinal distribution. Inclusive spectra of hadrons directly produced from beam jets are compared with data.     

Connes distance of 2D harmonic oscillators in quantum phase space

We study the Connes distance of quantum states of two-dimensional (2D) harmonic oscillators in phase space. Using the Hilbert-Schmidt operatorial formulation, we construct a boson Fock space and a quantum Hilbert space, and obtain the Dirac operator and a spectral triple corresponding to a four-dimensional (4D) quantum phase space. Based on the ball condition, we obtain some constraint relations about the optimal elements. We construct the corresponding optimal elements and then derive the Connes distance between two arbitrary Fock states of 2D quantum harmonic oscillators. We prove that these two-dimensional distances satisfy the Pythagoras theorem. These results are significant for the study of geometric structures of noncommutative spaces, and it can also help us to study the physical properties of quantum systems in some kinds of noncommutative spaces.     

Quantum evolution and classical flow in complex phase space

For a class of holomorphic perturbations of the harmonic oscillator inn degrees of freedom a local solution of the time-dependent Schrödinger equation in the Bargmann representation is constructed which pointwise propagates, to leading order in , along the classical trajectories in complex phase space.     

Double logs of perturbative QCD for parton jets and soft hadron spectra

The influence of coherence in a soft parton bremsstrahlung on hadron spectra in jets is discussed. We present a simple functional method for calculation of different inclusive parton distributions in the “plateau” region. Inclusive parton cross sections, spectra, multiplicities, energy and angular correlations, etc. are derived in the Double Logarithmic approximation.     

The correlation between charge and energy flow within cascade models for quark and hadron jets

We consider the ratio \(\frac{{\Delta Q}}{{\Delta \varepsilon }}\) of the charge and energy fraction carried by particles in the angular interval ΔΩ with respect to the jet axis, where we assume a recursive scheme for the hadron cascade. A measurement of this ratio inep andvp collisions determines the quark chargeQ _q at any angle ΔΩ and ine ⁺ e ^?-annihilations alsoQ _q ⁴ can be obtained. In hadron hadron collisions this ratio discriminates in a very direct way between different production models. We consider the “stopping quark” model, the “two dual sheet” model, and finally a leading cluster model. More data on \(\frac{{\Delta Q}}{{\Delta \varepsilon }}\) would be desirable at higher energies in particular for meson beams.     

Universility of hadron jets in soft and hard particle interactions at high energies

Hadron jet production is studied in softπ ^? p and cumulativeπ ^? C interactions at a 40 GeV/c momentum. The collective characteristics of jets and the form of the quark and diquark fragmentation into charted poins and neutral strange particles are analyzed. The results obtained are compared to analogous data fore ⁺ e ^? andv(≈v)p interactions. The hadron jet properties are also studied by means of relativistic invariant variables—the squared relative 4-velocities \(b_{ik} = - \left( {\frac{{P_i }}{{m_i }} - \frac{{P_k }}{{m_k }}} \right)^2 \) . The results obtained show that quark (diquark) fragmentation proceeds in a similar manner in soft hadron-hadron collisions, cumulative interactions on light nuclei,e ⁺ e ^? annihilation and deep inelasticv(≈v)p scattering. In the relativistically invariant variables the fragmentation function is similar for the hadronization of quarks and diquarks and it does not matter whether they are knocked out of usual hadrons or multiquark systems.     

The deconfining phase transition - influence of hadron resonances and strangeness

A model is developed for the hadron gas to the quark-gluon plasma phase transition which includes finite light quark and strange quark chemical potentials. A new generalized phase diagram incorporating the effects of strange particles is introduced and shows the strange chemical potential to be discontinuous. The influence of strange particles on the critical thermodynamic variables is found to be small.     

Flooding of chaotic eigenstates into regular phase space islands

We introduce a criterion for the existence of regular states in systems with a mixed phase space. If this condition is not fulfilled chaotic eigenstates substantially extend into a regular island. Wave packets started in the chaotic sea progressively flood the island. The extent of flooding by eigenstates and wave packets increases logarithmically with the size of the chaotic sea and the time, respectively. This new effect is observed for the example of island chains with just ten islands.     

Collective properties of the final state in processes involving the production of hadron jets

Experimental results obtained by studying soft hadron jets in pion-proton and pion-nucleus reactions at intermediate energies with the aid of traditional collective variables are presented. Analytic approximations that describe, at a qualitative level, the dependences of collective parameters on the energy and multiplicity are proposed. Estimates obtained for strong coupling constant by studying collective variables are in reasonable agreement with its world-average value and with the results extracted by using different methods. The behavior of traditional collective variables as functions of the multiplicity in various interactions makes it possible to obtain a universal estimate for the lower boundary of the region of experimental manifestations of jets in multiparticle-production processes.     

The geometry of a q-deformed phase space

The geometry of the q-deformed line is studied. A real differential calculus is introduced and the associated algebra of forms represented on a Hilbert space. It is found that there is a natural metric with an associated linear connection which is of zero curvature. The metric, which is formally defined in terms of differential forms, is in this simple case identifiable as an observable. Received: 26 November 1998 / Published online: 27 April 1999     

The reconstruction of diffractive object digital hologram at a short distance

By using a spherical wave as the reference wave, we recorded the in-line phase-shifting digital hologram of the 25th element of Chinese standard No. 3 resolution test pattern, and gave the corresponding numerical reconstructed results. Some problems concerning with the digital hologram recording and reconstruction of the diffractive object at a short distance are discussed. The experimental result shows that the resolution of the reconstructed image is better than 10μm, which is the limit by using this experimental arrangement.