Density correlators in a self-similar cascade

Multivariate density moments (correlators) of arbitrary order are obtained for the multiplicative self-similar cascade. This result is based on the calculation by Greiner, Eggers and Lipa (reference [1]) where the correlators of the logarithms of the particle densities have been obtained. The density correlators, more suitable for comparison with multiparticle data, appear to have even simpler form than those obtained in [1].Comment: 9 pages, 3 figures, uses epsfig.st

On the electroproduction on nuclei

Recent data on the electroproduction of hadrons on nuclei are discussed. The effects of the nuclear absorption are investigated using the Lund model for electroproduction on nucleons. A simple geometrical model with a minimal number of assumptions and free parameters is shown to describe the data reasonably well.Comment: 10 pages, 7 figures; minor corrections, version accepted for publication in European Physical Journal

A simple formula for Bose-Einstein corrections

In analogy with the quantum field theory of free bosons a simple integral representation is derived for recently proposed corrections describing the Bose Einstein effect. The saddle point approximation to these integrals results in a compact expression which sums effectively over all permutations of n particles with accuracy better than 2 per cent for more than seven strongly correlated bosons.Comment: 10 pages, LaTe

Stopped nucleons in configuration space

In this note, using the simplified colour string model, we study the configuration space distribution of stopped nucleons in heavy-ion collisions. Given this model, we find that the stopped nucleons from the target and the projectile end up separated from each other by a distance which increases with the collision energy. In consequence, for the center-of-mass energies larger than 6 or 10 GeV (depending on the details of the model), it appears that the stopped nucleons are not necessarily in thermal and chemical equilibrium, and the net-baryon density reached is likely not much higher than that already present in the colliding nuclei

Correlation of transverse momentum and multiplicity in a superposition model of nucleus-nucleus collisions

In p-p collisions the average transverse momentum is known to be correlated with the multiplicity of produced particles. The correlation is shown to survive in a superposition model of nucleus-nucleus collisions. When properly parameterized, the correlation strength appears to be independent of the collision centrality - it is the same in p-p and central A-A collisions. However, the correlation is strongly suppressed by the centrality fluctuations.Comment: 7 pages, 2 figures, minor corrections, to appear in Phys. Rev.

A Monte Carlo Study of Erraticity Behavior in Nucleus-Nucleus Collisions at High Energies

It is demonstrated using Monte Carlo simulation that in different nucleus$-$nucleus collision samples, the increase of the fluctuation of event factorial moments with decreasing phase space scale, called erraticity, is still dominated by the statistical fluctuations. This result does not depend on the Monte Carlo models. Nor does it depend on the concrete conditions, e.g. the collision energy, the mass of colliding nuclei, the cut of phase space, etc.. This means that the erraticity method is sensitive to the appearance of novel physics in the central collisions of heavy nuclei.Comment: 9 pages, 4 figures (in eps form

Multitude of ecstatic butterflies : a glimpse of the sublime in kitsch

You can expect now a subversive essay on butterflies, a text fluttering with glimpses rather than conclusions. Let me start perversely with a question which I may/will probably be unable to answer. Is there an opposition to Sublimity in Art? Is Kitsch the answer? Kitsch Capitalised is no longer kitsch, since it becomes an appropriately holy, architecturally capitalised category. Consider a landscape painting: well-fed, impressive specimens of tawny deer roam freely all over the meadow. Now consider another painting which presents the same lush meadow equipped with yellow butterflies. No, I have not finished my essay yet. I am troubled by Umberto Eco’s insight: if only a few of the ready-made formulas are used, the result is simply kitsch. “When the reportoire of stock formulas is used wholesale, then the result is an architecture like Gaudi’s Sagrada Familia: the same vertigo, the same stroke of genius”. If one sticks to the butterfly image, one can think of a famous painting by J. E. Millais, A Blind Girl. The arithmetics of the sublime will prove that we have here one butterfly only, one bunch of delicate flowers, one puddle, two rainbows, half a dozen birds, six cows, etc. Everything comes in small numbers. But what would happen, if one painting used all existing and extinct specimens of deer and all existing and extinct butterflies plus all the butterflies to come? I am not sure whether it already approaches sublimity, but it does make a difference. There are literary works which implement magnified kitsch successfully: in G.G. Marquez One Hundred Years of Solitude the rain of dead birds is coming down (can we say dead birds are raining cats and dogs?), yellow flowers cover up the town after the death of Jose Arcadio Buendia, finally: countless clouds of yellow butterflies accompany Mauricio Babilonia’s every step. Clouds of yellow but ter f l ie s is not just an image, it is a concept which will reappear conveniently in this essay