Impact Parameter Dependence of Inelasticity in pppp / ppˉp\bar{p} Collisions

We study the impact parameter dependence of inelasticity in the framework of an updated geometrical model for multiplicity distribution. A formula in which the inelasticity is related to the eikonal is obtained. This framework permits a calculation of the multiplicity distributions as well as the inelasticity once the eikonal function is given. Adopting a QCD inspired parametrization for the eikonal, in which the gluon-gluon contribution dominates at high energy and determines the asymptotic behavior of the cross sections, we find that the inelasticity decreases as collision energy is increased. Our results predict the KNO scaling violation observed at LHC energies by CMS Collaboration

Scaling violations: Connections between elastic and inelastic hadron scattering in a geometrical approach

Starting from a short range expansion of the inelastic overlap function, capable of describing quite well the elastic pp and $\bar{p}p$ scattering data, we obtain extensions to the inelastic channel, through unitarity and an impact parameter approach. Based on geometrical arguments we infer some characteristics of the elementary hadronic process and this allows an excellent description of the inclusive multiplicity distributions in $pp$ and $\bar{p}p$ collisions. With this approach we quantitatively correlate the violations of both geometrical and KNO scaling in an analytical way. The physical picture from both channels is that the geometrical evolution of the hadronic constituents is principally reponsible for the energy dependence of the physical quantities rather than the dynamical (elementary) interaction itself.Comment: 16 pages, aps-revtex, 11 figure

SOME STORIES OF BRASIL-JAPAN COLLABORATION AND CHACALTAYA MOUNTAIN

An international cooperation, named Brasil-Japan Collaboration of Chacaltaya Emulsion Chamber Experiment (B-J Collaboration) exposed 2.35 × 108 m2.s, during the period 15thJun, 1962 till 10thMay, 1988. It corresponds to 22 'runs' on Cosmic Rays and in this figure are not included photosensitive material set in the lower part of the two-storied emulsion chamber. Although 3 more 'runs' occurred after 1988, they were not included either, because they were not yet properly measured and because they contain mixed Japanese and Russian films. Chacaltaya Mountain was firstly used in 1947 for 2 meson observations and π - μ decays. It was a wise choice not only for these observations but also for the B-J Collaboration and for the Alpaca Project, running at neighbouring sites. The main results observed by the B-J Collaboration are presented

SOME STORIES OF BRASIL-JAPAN COLLABORATION AND CHACALTAYA MOUNTAIN

An international cooperation, named Brasil-Japan Collaboration of Chacaltaya Emulsion Chamber Experiment (B-J Collaboration) exposed 2.35 × 108 m2.s, during the period 15thJun, 1962 till 10thMay, 1988. It corresponds to 22 'runs' on Cosmic Rays and in this figure are not included photosensitive material set in the lower part of the two-storied emulsion chamber. Although 3 more 'runs' occurred after 1988, they were not included either, because they were not yet properly measured and because they contain mixed Japanese and Russian films. Chacaltaya Mountain was firstly used in 1947 for 2 meson observations and π - μ decays. It was a wise choice not only for these observations but also for the B-J Collaboration and for the Alpaca Project, running at neighbouring sites. The main results observed by the B-J Collaboration are presented

Hadron Rich And Centauro Events

An exploratory statistical analysis of the event C16S086I037 was possible to do using two simulations. A γ and hadron induced showers recognition done on this event through a best fitting procedure shows identification of 25 and 37 for γ and hadron induced showers, respectively. Assuming that the most energetic shower is the surviving particle of an interaction and the tertiary produced particles are from normal multiple pion production, the characteristics of the interaction are: Energy of primary particle E0 = 1, 061  TeV, Inelasticity of collision K = 0.81, Mean inelasticity of γ-ray < kγ > = 0.27, Hadron induced showers energy/Total energy Qh ′ = 0.90 ≈ Qh, Rapidity density Nh / Δ Y = (8.56 - 9.89), Mean energy of secondary hadrons < Eh > = (21.5 ± 4)  TeV, Mean transverse momentum < PTh > = (1.2 ± 0.2)  GeV/c, Upper bound of partial cross section σ ≤ (15 - 39) μ barn and life time τ ≤ 10-16  s. Without the surviving particle assumption, the values are: E0 = 873  TeV, K = 1.0, < kγ > = 1 / 3, Qh ′ = 0.90, Nh / Δ Y = (8.32 - 9.34), < Eh > = (21 ± 3.5)  TeV, < PTh > = (1.0 ± 0.16)  GeV/c. Using another simulation for energy determination with χ2 > 3.16 for best fitting results 22 and 40 for γ and hadron induced showers, respectively. Under the surviving particle assumption, the figures are: Energy of primary particle E0 = 1, 047  TeV, Inelasticity of collision K = 0.80, Mean inelasticity of γ-ray < kγ > = 0.27, Hadronic induced showers energy/Total energy Qh ′ = 0.89 ≈ Qh, Rapidity density Nh / Δ Y = (10.25 - 13.19), Mean energy of secondary hadrons < Eh > = (19 ± 3)  TeV, Mean transverse momentum < PTh > = (1.0 ± 0.2)  GeV/c. That is, we get almost similar figures independently of simulation and a mean transverse momentum for this hadron-rich event similar to the Centauro events. © 2007 Elsevier B.V. All rights reserved.175-176SUPPL.: COMPLETE131136Luksys, M., Ohsawa, A., Shibuya, E.H., (1983) Nucl. Inst. & Meth. B, 82, pp. 549-556Okamoto, M., Shibata, T., (1987) Nucl. Inst. & Meth. A, 257, pp. 155-176Fujinaga, T., Ichimura, M., Niihori, Y., Shibata, T., (1989) Nucl. Inst. & Meth. A, 276, pp. 317-339Tamada, M., Ohsawa, A., (2000) Nucl. Phys. B, 581, pp. 73-90Garvey, J., (1987) Rep. Prog. Phys., 50, pp. 1311-138

An Eas Event Observed In The Early Stage Of Development

Since 1969 the experiments of Brazil-Japan Collaboration showed the occurrence of a series of events, showing a region with a high concentration of electromagnetic particles, surrounded by isolated and/or groups of showers. These events were named "halo events" or "super-families". Currently, we have more than a dozen of such events. The first of them, due to its aspect, was named "Andromeda". We present here the main characteristics of a similar halo event, named C21S087I075. It has a halo region with many high energy showers in its border. Other small energy showers spread over the central and surrounding blocks (S088, S100, S101, I074). These isolated showers, classified as of hadronic or electromagnetic origin, present a fractional energy distribution compatible with that of a Centauro candidate event (C16S087I037), reported at this symposium [S.L.C. Barroso, P.C. Beggio, J.A. Chinellato, A.O. Carvalho, A. Mariano, R. Oliveira, E.H. Shibuya, in this issue of XIV ISVHECRI]. Moreover, the lateral distribution in the halo region is similar to that observed in other 3 halo events. © 2007 Elsevier B.V. All rights reserved.175-176SUPPL.: COMPLETE182185Chacaltaya Emulsion Chamber Experiment (1971) Prog. Theor. Phys. Suppl., 47, pp. 1-125Okamoto, M., Shibata, T., (1987) Nucl. Inst. & Meth. A, 257, pp. 155-176Fujinaga, T., Ichimura, M., Niihori, Y., Shibata, T., (1989) Nucl. Inst. & Meth. A, 276, pp. 317-339Yamashita, S., (1985) J. Phys. Soc. of Japan, 54 (2), pp. 529-543Ohta, I., Mizutani, K., Kasahara, K., Kobayashi, T., Mikumo, E., Mito, I., Ohsawa, A., Takahashi, Y., (1979) Nucl. Inst. & Meth., 161, pp. 35-5

Uniqueness Of Centaouro-type Events

Analysis to discriminate Centauro events from normal events is made without previous identification of secondary emitted particles. For this purpose their energy and derived quantities like distance from the center of momenta it were mainly used. As a result we found in a sample of (280+87) experimental events only 3 were compatible with 5 Centauro events, but none of them had a high content of hadrons, characteristic of Centauro events. With this result we are confident about the uniqueness of Centauro events, especially for two events that have vertex directly determined. Comparing with some interaction models features we depict a possible scenario to explain Centauro events.122197200Pancheri, G., Rubbia, C., (1984) Nucl. Phys., A418, p. 117Gaisser, T.K., Halzen, F., (1985) Phys. Rev. Lett., 54 (16), p. 1754(1989), p. 327. , B-J Collaboration, 41th Brazilian Society for Promotion of Science, Fortaleza-Ceará(1989) and 10th Brazilian National Meeting on Particle and Fields, Itatiaia-Rio de JaneiroAugusto, C.R.A., Barroso, S.L.C., Beggio, P.C., Carvalho, A.O., Menon, M.J., Navia, C.E., Oliveira, R., Shibuya, E.H., (2001), p. 1422. , (BRAZIL-JAPAN COLLABORATION OF CHACALTAYA EMULSION CHAMBER EXPERIMENT), Proc.27th ICR Hamburg, HE300Augusto, C.R.A., Barroso, S.L.C., Beggio, P.C., Carvalho, A.O., Menon, M.J., Navia, C.E., Oliveira, R., Shibuya, E.H., (2001), p. 1537. , (BRAZIL-JAPAN COLLABORATION OF CHACALTAYA EMULSION CHAMBER EXPERIMENT, Proc.27th ICR Hamburg, HE3.0

Identification Of Hadrons In Centauro Events

Since the observation of a remarkable cosmic ray induced event, in experiments with emulsion chambers, a search for similar events was started. In spite of no observation of events showing the unusual aspect of Centauro I, another remarkable event with a high content of hadrons was observed. Moreover, this Centauro V has a hadron that interacts twice at deeper layers of the detector and has energy between (16-20)% of the total energy of the main interaction, the former figure for all showers and the last only for hadron-induced showers. Therefore, to classify it as a Centauro type event it is crucial to look for reasonable criterion to identify hadronic particles. Previous analysis adopted only one criterion for each shower observed in the films. Nowadays, an improved re-analysis uses at least two criteria for each shower. The main purpose of this paper is to show that the showers observed are properly identified as of hadronic origin and so we conclude that is an authentic Centauro event produced by the interaction of a hadron 500 m above the detector and interacting twice in the lower part of the chamber.122193196Augusto, C.R.A., Barroso, S.L.C., Beggio, P.C., Carvalho, A.O., Menon, M.J., Navia, C.E., Oliveira, R., Shibuya, E.H., (Brasil-Japan Collaboration of Chacaltaya Emulsion Chamber Experiment), uniqueness of Centauro-type events, submitted to this symposium.)(1971) Prog. Theor. Phys. Suppl., 47, p. 1. , Brasil-Japan Collaboration of Chacaltaya Emulsion Chamber ExperimentLattes, C.M.G., Fujimoto, Y., Hasegawa, S., (1980) Phys. Rep., 65, p. 151(1983) Prog. Theor. Phys. Suppl., 76, p. 1. , Brasil-Japan Collaboration of Chacaltaya Emulsion Chamber ExperimentPancheri, G., Rubbia, C., (1984) Nucl. Phys., A418, pp. 117cAlexopoulos, T., (1988) Phys. Rev. Lett., 60, p. 162

Comparison Of Centauro And Usual γ's Events

The B-J Collaboration experiments discovered high transverse momenta in hadronic interactions, through cosmic ray events. Among then, mean transverse momenta <PTh> of the order of 1 GeV/c events were found and such events were nicknamed Centauro events. As the high transverse momenta are of hadronic particles, naturally this is connected with the criteria of identification of secondaries. To have more confidence on the abnormal features of Centauro events, we used the Kolmogorov-Smirnov non parametric test, aiming to show the discrepancy with normal events.751-2150152Lattes, C.M.G., Fujimoto, Y., Hasegawa, S., (1980) Phys.Rep., 65 (3), p. 15