Towards a Blacker, Edgier and Larger proton

Henzi, R.; Valin, P.

doi:10.1016/0370-2693(83)90344-1

Cited by 61 publications

(51 citation statements)

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“…The values ζ = 0.7 and 1.0 correspond to ISR and LHC energies and agree well with the result of detailed fitting to the elastic scattering data [4][5][6]. A further increase of ζ leads to the change of the BEL regime (Blacker, Edgier, Larger - [7]) by the toroid-like shape with a dip at b = 0 (TEH regime-Toroidal Elastic Hollow- [8][9][10][11]) The values ζ = 1.5 are proposed in [12,13] and ζ = 1.8 in [14] as describing the asymptotical regimes. The value ζ = 2 corresponds to the so-called "black disk" regime with equal elastic and inelastic cross sections (σ el = σ inel = 0.5σ tot ).…”

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confidence: 69%

Unexpected behaviour of cross sections of high energy protons

Dremin

2017

EPJ Web Conf.

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Abstract. Nobody expected that protons will try to keep their entity in their collisions at higher and higher energies. However, the comparison of experimental results on proton-proton interactions from ISR to LHC energies clearly shows this tendency with a definitely increasing share of the elasic scattering cross section. This unexpected behaviour immediately leads to the unexpected corollary about the shape of the spatial interaction region of the two protons. The unquestionable principle of unitarity combined with available experimental data on elastic scattering is used to get new conclusions about this shape. Its evolution at present energies from the ISR to the LHC and predictions about its behaviour at ever higher energies are considered. The shape can transform rather drastically if the share of elastic processes keeps rising. The possible origin of the effect and its interrelation to the strong interaction dynamics are speculated. Cosmic ray studies can help in clarifying this behaviour.Experimental data on proton-proton interactions in high energy collisions show quite a special and unexpected behaviour of the share of elastic scattering compared to inelastic processes with increasing energy. It decreases at the beginning (at comparatively low energies) but then starts to increase. From Intersecting Storage Rings (ISR) energies of 20-60 GeV up to higher energies 7-13 TeV at the Large Hadron Collider (LHC) it increases by more than a factor 1.5! According to intuitive classical ideas we would expect a stable tendency with increasing share of the break-down of protons compared to their survival probability.If a cup falls to the floor, it breaks into pieces but sometimes stays intact. The harder it hits the floor, the less chance to be unbroken.If two high energy protons collide, many new particles (mostly pions) are produced, but sometimes they scatter elastically and retain their entity. It is surprising enough that at very high collision energies the proportion of elastic processes increases with increasing energy from the ISR to the LHC.One can assume that either the asymptotic freedom or the extremely short time of flight of high energy protons through each other are in charge of such a surprising effect. The unquestionable principle of unitarity combined with the available experimental data on elastic scattering is used to get new conclusions about the shape of the interaction region of colliding protons. Its evolution at present energies is considered. Some predictions about its behaviour at even higher energies are described with different assumptions on the relative roles of elastic scattering and inelastic processes. The shape can transform rather drastically if the proportion of elastic processes keeps rising. This unexpected property leads to an unexpected corollary. The possible origin of the effect a e-mail: dremin@td.lpi.ru and its interrelation to the strong interaction dynamics are speculated.Our main goal here is to get some knowledge about the spatial region of interactions of high ene...

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confidence: 69%

Unexpected behaviour of cross sections of high energy protons

Dremin

2017

EPJ Web Conf.

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“…Since the ratio σ el /σ tot increases above 100 GeV, it does not come as a surprise that the central inelastic overlap integral G in (0), in passing from the ISR to the CERN proton-antiproton collider, increases, as shown by Henzi and Valin, 56 at variance from what happens in the ISR energy range (Fig. 27).…”

Section: The Isr "Small-angle Physics" Seen From Higher Energiesmentioning

confidence: 74%

An ISR Discovery: The Rise of the Proton–Proton Cross-Section

Amaldi

2015

Advanced Series on Directions in High Energy Physics

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The Intersecting Storage Rings (ISR) were the first hadron collider ever built, providing proton-proton collisions at centre-of-mass energies as high as 62 GeV, almost five times larger than any previous accelerator. When in 1971 the ISR began operation the Reggepole approach dominated and the proton-proton total cross-section was expected to have already reached a finite asymptotic value. However, ISR experiments found that the cross-section was rising by 10% between 22 and 62 GeV, while the interaction radius was increasing by 5%, a trend that continues up to the hundred times larger energies available at the Large Hadron Collider. In order to accurately measure the total and elastic cross-sections, new experimental methods -uniquely adapted to the environment of a hadron collider -had to be developed; they are described in the central part of this paper, which closes with a review of the data obtained at the LHC since they put in a wider perspective the forty years old ISR results.

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“…From the geometrical point of view the general picture is that protons become blacker, edgier and larger (BEL) [27]. We discuss it later.…”

Section: Where Do We Stand Now?mentioning

confidence: 99%

Hadron Structure and Elastic Scattering

Dremin

2014

Pomeranchuk 100

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Prelude.It was in September 1954 when I met Pomeranchuk. He lectured Theory of Relativity. Next year he became a tutor of our "theoretical group". In some time he proposed me to learn the book of Flügge on nuclear physics. After struggling with difficult subject written in German I asked him some questions. He liked it and one by one proposed several problems to be solved. In parallel, he insisted on passing through the series of famous Landau exams. It was a good school. Its lessons I described in the book of reminiscences about Pomeranchuk. As a supervisor, he advised my diploma paper to be published in JETP Letters and recommended me to Prof. Tamm as a PhD student. Soon I proposed the one-pion exchange model which was later extended to multiperipheral and multireggeon models. Pomeranchuk got interested in it and asked me to come for discussion. He was deeply interested in properties of hadron collisions. Our contacts lasted till his death.In this paper I describe some new findings about elastic scattering of hadrons studied now up to LHC energies. I briefly reviewed this at the Pomeranchuk centennial seminar at ITEP. This would be extremely interesting subject for him. Let me just mention Pomeron and famous Pomeranchuk theorem to remind you his basic contributions in this field. I dedicate the paper to the memory of my teacher Isaak Pomeranchuk. AbstractWhen colliding, the high energy hadrons can either produce new particles or scatter elastically without change of their quantum numbers and other particles produced. Namely elastic scatterings of hadrons are considered in this paper. The general machinery of their theoretical treatment is described. Some new experimental data are presented and confronted to phenomenological approaches. The internal structure of hadrons is the main subject of these studies. Its impact on properties of their interactions is reviewed. It is shown that protons become larger and darker with increase of their collision energy and reveal some substructure. The violation of the geometric scaling in the diffraction cone and new problems of description of differential cross sections outside it are described.

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Towards a Blacker, Edgier and Larger proton

Cited by 61 publications

References 11 publications

Unexpected behaviour of cross sections of high energy protons

Unexpected behaviour of cross sections of high energy protons

An ISR Discovery: The Rise of the Proton–Proton Cross-Section

Hadron Structure and Elastic Scattering

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