V. Rossi

The «leading»-particle effect in hadron physics

SummaryA world review is presented of the «leading»-particle effect in hadron physics: baryon-baryon, baryon-antibaryon, mesonbaryon and photon-baryon processes are studied and compared with hadron production from an initial state which does not contain any hadron. In this latter case the «leading» effect is not present. It is shown that the «leading»-particle effect is fully present even in hadron interactions initiated by neutrinos. The importance of the «leading» effect in hadron physics is discussed.RiassuntoSi presenta una rassegna mondiale dell’effetto di particella «leading» in fisica adronica. Processi del tipo barione-barione, barione-antibarione, mesone-barione e fotone-barione sono studiati e confrontati con la produzione di adroni da uno stato iniziale che non contiene adroni. In quest’ultimo tipo di processi non è presente l’effetto «leading». Si dimostra che l’effetto di particella «leading» è sicuramente presente anche nelle interazioni iniziate da neutrini con adroni nello stato finale. Si discute infine l’importanza dell’effetto «leading» nella fisica adronica.РеэюмеПроводится аналиэ зффекта «лидируюшей» частицы в адронной фиэике. Исследуются барион-барионные, барион-антибарионные, меэон-барионные и протон-барионные процессы. Проводится сравнение с процессом обраэования адрона иэ начального состояния, которое не содержит адрона. В зтом последнем случае зффект «лидируюшей» частицы отсутствует. Покаэывается, что зффект «лидируюшей» частицы имеет место в адронных вэаимодействиях, инициированных нейтрино. Обсуждается важность зффекта «лидируюшей» частицы в адронной фиэике.

The inclusive transverse-momentum distribution in hadronic systems produced in proton-proton collisions

Summary. The single.particle inclusive transverse-momentum distribution in the multiparticle systems produced in low-1~T proton-proton interactions at ~- 30 and 62 GoV has been studied. The analysis was performed removing from the final state the leading proton and redefining the effective hadronie energy available for particle production. Excellent agreement for effective hadronic energies up to 13 GoV is found between (pp) and (e+e-). At higher energy the (pp) data show a less pronounced growth than the (e+e -) data.

Primary Ionization Measurement in a Large Avalanche Chamber for Free Quark Detection

The WA44 experiment is a search for free quarks (1/3, 1/2) produced in high energy v interactions. High detection efficiency for quarks is achieved by measurement of primary ionization in a triggered large avalanche chamber which, moreover, provides the high spatial resolution required for high multiplicity jet-type events. The chamber is 2.35 × 1.25 × 0.6 m3 and is flushed with a mixture of pure He-Ne (80-20%). The chamber is photographed with 3 cameras using image intensifiers giving 1.4 mm resolution in space. The optical gain is such that the chamber can be operated well below the streamer threshold. In order to obtain precise primary ionization measurements and high rejection coefficient for quark detection against charge 1 particles, a good high voltage pulse stability (< 1% FWHM) and a long memory time (at least 100 μs) are essential and have been achieved. Data taking is in progress. Preliminary results show that the avalanche chamber is an excellent triggerable detector for combining good spatial multitrack resolution and accurate primary ionization measurement.

What We can Learn from High-Energy, Soft (pp) Interactions

The purpose of this review is to report on a series of similarities between multiparticle hadronic systems produced in (pp) interactions and in (e+e−) annihilation1–12. The new feature of this work is the fact that, in order to establish these similarities, the basic principle is to evaluate, for each (pp) interaction, the correct energy available for particle production. The old trend was to select high-p T processes.

A detailed study of vs. Ehad andm1,2 at different% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfKttLearuqr1ngBPrgarmqr1ngBPrgitL% xBI9gBamXvP5wqSXMqHnxAJn0BKvguHDwzZbqegm0B1jxALjhiov2D% aeHbuLwBLnhiov2DGi1BTfMBaebbfv3ySLgzGueE0jxyaibaiyc9qr% pepeeu0dXdh9vqqj-hEeeu0xXdbba9frFj0-OqFfea0dXdc9LqpGe9% FjuP0-is0dXdbba9pGe9xq-Jbba9suk9fr-xfr-xfrpeWZqaaeaabi% GaciaacaqabeaadaabauaaaOqaamaabmaabaWaaOaaaeaacqaI4aao% aSqabaaakiaawIcacaGLPaaadaWgaaWcbaacbaGae8hCaaNae8hCaa% habeaaaaa!482A! in (pp) interactionsin (pp) interactions

By using (pp) interactions at three different c.m. energies,\(\left( {\sqrt 8 } \right)_{pp} \)=30, 44, 62 GeV, it is shown that the average charged-particle multiplicity vs. the invariant mass of the hadronic systemm1,2 has the same behaviour as it hasvs. 2Ehad. Moreover, in both cases is shown to be nearly independent of\(\left( {\sqrt 8 } \right)_{pp} \) and in good agreement with the average charged-particle multiplicity measured in the (e+e−) annihilation.SummaryBy using (pp) interactions at three different c.m. energies, % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfKttLearuqr1ngBPrgarmqr1ngBPrgitL% xBI9gBamXvP5wqSXMqHnxAJn0BKvguHDwzZbqegm0B1jxALjhiov2D% aeHbuLwBLnhiov2DGi1BTfMBaebbfv3ySLgzGueE0jxyaibaiyc9qr% pepeeu0dXdh9vqqj-hEeeu0xXdbba9frFj0-OqFfea0dXdc9LqpGe9% FjuP0-is0dXdbba9pGe9xq-Jbba9suk9fr-xfr-xfrpeWZqaaeaabi% GaciaacaqabeaadaabauaaaOqaamaabmaabaWaaOaaaeaacqaI4aao% aSqabaaakiaawIcacaGLPaaadaWgaaWcbaacbaGae8hCaaNae8hCaa% habeaaaaa!482A!

Search for open «top» at the CERN\((p\bar p)\) collidercollider

\left( {\sqrt 8 } \right)_{pp}

A Detailed Study of Average Charged Particle Multiplicity Versus Available Energy and Invariant Mass at Different

=30, 44, 62 GeV, it is shown that the average charged-particle multiplicity vs. the invariant mass of the hadronic systemm1,2 has the same behaviour as it hasvs. 2Ehad. Moreover, in both cases is shown to be nearly independent of % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfKttLearuqr1ngBPrgarmqr1ngBPrgitL% xBI9gBamXvP5wqSXMqHnxAJn0BKvguHDwzZbqegm0B1jxALjhiov2D% aeHbuLwBLnhiov2DGi1BTfMBaebbfv3ySLgzGueE0jxyaibaiyc9qr% pepeeu0dXdh9vqqj-hEeeu0xXdbba9frFj0-OqFfea0dXdc9LqpGe9% FjuP0-is0dXdbba9pGe9xq-Jbba9suk9fr-xfr-xfrpeWZqaaeaabi% GaciaacaqabeaadaabauaaaOqaamaabmaabaWaaOaaaeaacqaI4aao% aSqabaaakiaawIcacaGLPaaadaWgaaWcbaacbaGae8hCaaNae8hCaa% habeaaaaa!482A!