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A. Bialas

Publications and source records attributed to A. Bialas.

69 records · Page 4Linked to original sources
arXiv1998

Bose-Einstein condensation and independent production of pions

The influence of the HBT effect on the momentum spectra of independently produced pions is studied using the method developed earlier for discussion of multiplicity distributions. It is shown that in this case all the spectra and multiparticle correlation functions are expressible in terms of one function of two momenta. It is also shown that at the critical point all pions are attracted into one quantum state and thus form a Bose-Einstein condensate.

hep-ph↗
arXiv1998

HBT correlations and charge ratios in multiple production of pions

The influence of the HBT effect on the multiplicity distribution and charge ratios of independently produced pions is studied. It is shown that, for a wide class of models, there is a critical point, where the average number of pions becomes very large and the multiplicity distibution becomes very broad. In this regime unusual charge ratios ("centauros", "anticentauros") are strongly enhanced. The prospects for reaching this regime are discussed.

hep-ph↗
arXiv1997

Towards an unified description of total and diffractive structure functions at HERA in the QCD dipole picture

It is argued that the QCD dipole picture allows to build an unified theoretical description -based on BFKL dynamics- of the total and diffractive nucleon structure functions. This description is in qualitative agreement with the present collection of data obtained by the H1 collaboration. More precise theoretical estimates, in particular the determination of the normalizations and proton transverse momentum behaviour of the diffractive components, are shown to be required in order to reach definite conclusions.

hep-ph↗
arXiv1997

The QCD triple Pomeron coupling from string amplitudes

Using the recent solution of the triple Pomeron coupling in the QCD dipole picture as a closed string amplitude with six legs, its analytical form in terms of hypergeometric functions and numerical value are derived.

hep-ph↗
arXiv1997

High-mass diffraction in the QCD dipole picture

Using the QCD dipole picture of the BFKL pomeron, the cross-section of single diffractive dissociation of virtual photons at high energy and large diffractively excited masses is calculated. The calculation takes into account the full impact-parameter phase-space and thus allows to obtain an exact value of the triple BFKL Pomeron vertex. It appears large enough to compensate the perturbative 6-gluon coupling factor (alpha/pi)^3 thus suggesting a rather appreciable diffractive cross-section.

hep-ph↗
arXiv1997

Total $γ^{\star}γ^{\star}$ cross section and the BFKL pomeron

In the framework of the dipole picture of the BFKL pomeron we discuss a few possibilities of calculating the total $γ^{\star}γ^{\star}$ cross section of the virtual photons. We argue that the existing successful fits of the dipole picture formulae to the measured structure functions $F_2(Q^2,x)$ favor one of the possible extensions of the dipole picture of the BFKL pomeron formulated recently by one of us.

hep-ph↗
arXiv1996

Nuclear beams in HERA

A study has been made of the physics interest and feasibility of experiments with nuclear beams in HERA. It is shown that such experiments widen considerably the horizon for probing QCD compared to that from free nucleon targets. In addition there is some sensitivity to physics beyond the standard model. Hence the option to include circulating nuclear beams in HERA allows a wide range of physics processes to be studied and understood.

hep-ph↗
arXiv1996

Hard Diffraction From Quasi-Elastic Dipole Scattering

The contribution to diffraction dissociation of virtual photons due to quasi-elastic scattering of the $q$-$\bar q$ component is calculated in the framework of the QCD dipole picture. Both longitudinal and transverse components of the cross-section are given. It is shown that, at fixed mass of the diffractively produced system, quantum mechanical interference plays an important r\^ ole. Phenomenological consequences are discussed.

hep-ph↗
arXiv1996

Intermittency in a single event

The possibility to study intermittency in a single event of high multiplicity is investigated in the framework of the $α-$model. It is found that, for cascade long enough, the dispersion of intermittency exponents obtained from individual events is fairly small. This fact opens the possibility to study the distribution of the intermittency parameters characterizing the cascades seen (by observing intermittency) in particle spectra.

hep-ph↗
arXiv1996

Hard Diffraction in the QCD Dipole Picture

Using the QCD dipole picture of the BFKL pomeron, the gluon contribution to the cross-section for single diffractive dissociation in deep-inelastic high-energy scattering is calculated. The resulting contribution to the proton diffractive structure function integrated over $t$ is given in terms of relevant variables, $x_{\cal P}, Q^2, $ and $β= x_{Bj}/x_{\cal P}.$ It factorizes into an explicit $x_{\cal P}-$dependent Hard Pomeron flux factor and structure function. The flux factor is found to have substantial logarithmic corrections which may account for the recent measurements of the Pomeron intercept in this process. The triple Pomeron coupling is shown to be strongly enhanced by the resummation of leading logs. The obtained pattern of scaling violation at small $β$ is similar to that for $F_2$ at small $x_{Bj}.$

hep-ph↗
arXiv1995

INITIAL-STATE COLOUR DIPOLE EMISSION ASSOCIATED WITH QCD POMERON EXCHANGE

The initial-state radiation of soft colour dipoles produced together with a single QCD Pomeron exchange (BFKL) in onium-onium scattering is calculated in the framework of Mueller's approach. The resulting dipole production grows with increasing energy and reveals an unexpected feature of a power-law tail at appreciably large transverse distances from the collision axis, this phenomenon being related to the scale-invariant structure of dipole-dipole correlations.

hep-ph↗
arXiv1994

Intermittency and Exotic Channels

It is pointed out that accurate measurements of short-range two-particle correlations in like-charge $ Kπ$ and in $ π^ 0π^ 0$ channels should be very helpful in determining the origin of the \lq\lq intermittency\rq\rq\ phenomenon observed recently for the like-charge pion pairs.

hep-ph↗