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Giulia Pancheri

Publications and source records attributed to Giulia Pancheri.

At least 19 recordsLinked to original sources

Particle accelerators as a path to intergovernmental collaboration: the case of the first electron positron collider and the power of theoretical physics

I rivisit the history of the first matter-antimatter collider built in Italy in 1960 and carried to success through an inter-European collaboration with France, underlying the foundational role of the Austrian born theoretical physicist Bruno Touschek. Touschek's life path through Europe before and after World War II is briefly recalled. The role of CERN in jump-starting this international collaboration between the Frascati National Laboratories in Italy and the Orsay Linear Accelerator Laboratory in France, is highlighted through historical documents, and contributions from interviews with the main protagonists of Touschek's game-changing proposal.

physics.hist-ph

Raoul Gatto and Bruno Touschek's joint legacy in the rise of electron-positron physics

Raoul Gatto and Bruno Touschek's collaboration in the establishment of electron positron colliders as a fundamental discovery tool in particle physics will be illustrated. In particular, we will tell the little-known story of how Gatto and Touschek's pioneering vision combined to provide the theoretical foundations for AdA, the first matter-antimatter collider, and how their friendship with Wolfgang Pauli and Gerhard Lüders was crucial to their understanding of the CPT theorem, the basis for AdA's success. We will see how these two exceptional scientists shaped physics between Rome and Frascati, from the proposal to build AdA and, soon after in 1961, the larger machine ADONE, to the discovery of the $J/Ψ$ particle in 1974. We will also highlight Gatto and Touschek's contribution in mentoring an extraordinary cohort of students and collaborators whose work contributed to the renaissance of Italian theoretical physics after the Second World War and to the establishment of the Standard Model of particle physics.

physics.hist-ph

About soft photon resummation

The first time one of us (G.P.) encountered Earle was in Summer 1966, when she was directed to study Earle's papers on radiative corrections to quasi-elastic electron scattering. The suggestion had come from Bruno Touschek, at the time head of the theoretical physics group at the Frascati National Laboratories near Rome. About the same time, Earle came from MIT to visit University of Rome and Frascati. G.P. was a young post-graduate, who had studied Earle's papers and was awed by his already impressive scientific figure. After almost 40 years had passed, Earle visited Italy with his wife Ruth, making Frascati their base for an extended visit of almost a month. They were housed in what was then the laboratory hostel for foreign visitors, a small villa higher up above the hill, toward the town of Frascati. Since then, we became close friends, a friendship which included both his family and ours, and which has been very important for us. In memory of that first visit and in gratitude for the many years of friendship, we will tell here a story of infrared radiative corrections to charged particle scattering, to which Earle's papers gave an important contribution.

physics.hist-ph

Bruno Touschek in Glasgow. The making of a theoretical physicist

In the history of the discovery tools of last century particle physics, central stage is taken by elementary particle accelerators and in particular by colliders. In their start and early development, a major role was played by the Austrian born Bruno Touschek, who proposed and built the first electron positron collider, AdA, in Italy, in 1960. In this note, we present a period of Touschek's life barely explored in the literature, namely the five years he spent at University of Glasgow, first to obtain his doctorate in 1949 and then as a lecturer. We shall highlight his formation as a theoretical physicist, his contacts and correspondence with Werner Heisenberg in Göttingen and Max Born in Edinburgh, as well as his close involvement with colleagues intent on building modern particle accelerators in Glasgow, Malvern, Manchester and Birmingham. We shall discuss how the Fuchs affair, which unraveled in early 1950, may have influenced his decision to leave the UK, and how contacts with the Italian physicist Bruno Ferretti led Touschek to join the Guglielmo Marconi Physics Institute of University of Rome in January 1953.

physics.hist-ph

Touschek with AdA in Orsay and the first direct observation of electron-positron collisions

We describe how the first direct observation of electron-positron collisions took place in 1963-1964 at the Laboratoire de l'Accélérateur Linéaire d'Orsay, in France, with the storage ring AdA, which had been proposed and constructed in the Italian National Laboratories of Frascati in 1960, under the guidance of Bruno Touschek. The obstacles and successes of the two and a half years during which the feasibility of electron-positron colliders was proved will be illustrated using archival and forgotten documents, in addition to transcripts from interviews with Carlo Bernardini, Peppino Di Giugno, Mario Fascetti, Francois Lacoste, and Jacques Haïssinski.

physics.hist-ph

Modeling Double Parton Scattering at LHC

We examine present data for double parton scattering at LHC and discuss their energy dependence from its earliest measurements at the ISR. Different models for the effective cross-section are considered and their behavior studied for a variety of selected final states. We point out that data for pp ->4 jets or pp -> quarkonium pair indicate the effective cross-section to increase with energy. We compare this set of data with different models, including one inspired by our soft gluon resummation model for the impact parameter distribution of partons.

hep-ph

Bruno Touschek in Germany after the War: 1945-46

Bruno Touschek was an Austrian born theoretical physicist, who proposed and built the first electron-positron collider in 1960 in the Frascati National Laboratories in Italy. In this note we reconstruct a crucial period of Bruno Touschek's life so far scarcely explored, which runs from Summer 1945 to the end of 1946. We shall describe his university studies in Göttingen, placing them in the context of the reconstruction of German science after 1945. The influence of Werner Heisenberg and other prominent German physicists will be highlighted. In parallel, we shall show how the decisions of the Allied powers towards restructuring science and technology in the UK after the war effort, determined Touschek's move to the University of Glasgow in 1947.

physics.hist-ph

Analysis and implications of precision near-forward TOTEM data

Very precise data on elastic proton-proton scattering at $\sqrt{s}=7$, $8$ and $13$ TeV have been obtained by the TOTEM group at LHC in the near-forward region (momentum transfers down to $|t| = 6 \times 10^{-4}\ {\rm GeV}^2$ at $\sqrt{s}=8$ TeV and to $|t| = 8 \times 10^{-4}\ {\rm GeV}^2$ at $\sqrt{s}=13$ TeV). The Coulomb-nuclear interference has been measured with sufficient accuracy for TOTEM to establish the falloff of the $ρ$ parameter with increasing energy. The predictions from a previously studied model are shown to be in good agreement with the data and thus allow us to draw rather firm conclusions about the structure of the near-forward nuclear amplitude. We point out that due to a zero in the real part of the nuclear amplitude occurring at a very small momentum transfer--that can migrate into the Coulomb-nuclear interference (CNI) region at higher energies--much care is needed in extracting the numerical value of $ρ$ for such energies. Thus, the true value of $ρ$ would be higher than the TOTEM value for $ρ$ found under the hypothesis that the real part of the elastic nuclear amplitude is devoid of such a zero in the CNI region.

hep-ph

PHOTON-2017 conference proceedings

This document collects the proceedings of the PHOTON 2017 conference ("International Conference on the Structure and the Interactions of the Photon", including the 22th "International Workshop on Photon-Photon Collisions", and the "International Workshop on High Energy Photon Colliders") held at CERN (Geneva) in May 2017. The latest experimental and theoretical developments on the topics of the PHOTON conference series are covered: (i) $γ\,γ$ processes in e$^+$e$^-$, proton-proton (pp) and nucleus-nucleus (AA) collisions at current and future colliders, (ii) $γ$-hadron interactions in e$^\pm$p, pp, and AA collisions, (iii) final-state photon production (including Standard Model studies and searches beyond it) in pp and AA collisions, and (iv) high-energy $γ$-ray astrophysics. These proceedings are dedicated to the memory of Maria Krawczyk.

hep-ph

Bruno Touschek and AdA: from Frascati to Orsay. In memory of Bruno Touschek, who passed away 40 years ago, on May 25th, 1978

The first electron-positron collisions in a laboratory were observed in 1963-1964 at the Laboratoire de l'Accélérateur Linéaire d'Orsay, in France, with the storage ring AdA, which had been constructed in the Italian National Laboratories of Frascati in 1960, under the guidance of Bruno Touschek. The making of the collaboration between the two laboratories included visits between Orsay and Frascati, letters between Rome and Paris, and culminated with AdA leaving Frascati on July 4th, 1962 to cross the Alps on a truck, with the doughnut degassed to $10^{-9}$mmHg through pumps powered by sets of heavy batteries. This epoch-making trip and the exchanges which preceded it are described through unpublished documents and interviews with some of its protagonists, Carlo Bernardini, Francois Lacoste, Jacques Haïssinski, Maurice Lévy.

physics.hist-ph

Maria Krawczyk: friend and physicist

With this note, we remember our friend Maria Krawczyk, who passed away this year, on May 24th. We briefly outline some of her physics interests and main accomplishments, and her great human and moral qualities.

physics.hist-ph

The path to high-energy electron-positron colliders: from Wideroe's betatron to Touschek's AdA and to LEP

We describe the road which led to the construction and exploitation of electron positron colliders, hightlighting how the young physics student Bruno Touschek met the Norwegian engineer Rolf Wideroe in Germany, during WWII, and collaborated in building the 15 MeV betatron, a secret project directed by Wideroe and financed by the Ministry of Aviation of the Reich. This is how Bruno Touschek learnt the science of making particle accelerators and was ready, many years later, to propose and build AdA, the first electron positron collider, in Frascati, Italy, in 1960. We shall then see how AdA was brought from Frascati to Orsay, in France. Taking advantage of the Orsay Linear Accelerator as injector, the Franco-Italian team was able to prove that collisions had taken place, opening the way to the use of particle colliders as a mean to explore high energy physics.

physics.hist-ph

Photoproduction with a mini-jet model and Cosmic Ray showers

We present post-LHC updates of estimates of the total photo-production cross section in a mini-jet model with infrared soft gluon resummation, and apply the model to study Cosmic Ray shower development, comparing the results with those obtained from other existing models.

hep-ph

Inelastic cross-section and Survival Probabilities at LHC in mini-jet models

Recent results for the total and inelastic hadronic cross-sections from LHC experiments are compared with predictions from a single channel PDF driven eikonal mini-jet model and from an empirical model. The role of soft gluon resummation in the infrared region in taming the rise of mini-jets and their contribution to the increase of the total cross-sections at high energies are discussed. Survival probabilities at LHC, whose theoretical estimates range from circa 10 percent to a few per mille, will be estimated in this model and compared with results from QCD inspired models and from multi channel eikonal models. We revisit a previous calculation and examine the origin of these discrepancies.

hep-ph

Introduction to the physics of the total cross-section at LHC: A Review of Data and Models

This review describes the development of the physics of hadronic cross sections up to recent LHC results and cosmic ray experiments. We present here a comprehensive review - written with a historical perspective - about total cross-sections from medium to the highest energies explored experimentally and studied through a variety of methods and theoretical models for over sixty years. We begin by recalling the analytic properties of the elastic amplitude and the theorems about the asymptotic behavior of the total cross-section. A discussion of how proton-proton cross-sections are extracted from cosmic rays at higher than accelerator energies and help the study of these asymptotic limits, is presented. This is followed by a description of the advent of particle colliders, through which high energies and unmatched experimental precisions have been attained. Thus the measured hadronic elastic and total cross-sections have become crucial instruments to probe the so called soft part of QCD physics, where quarks and gluons are confined, and have led to test and refine Regge behavior and a number of diffractive models. As the c.m. energy increases, the total cross-section also probes the transition into hard scattering describable with perturbative QCD, the so-called mini-jet region. Further tests are provided by cross-section measurements of gamma p, gamma*p and gamma* gamma* for models based on vector meson dominance, scaling limits of virtual photons at high Q^2 and the BFKL formalism. Models interpolating from virtual to real photons are also tested.

hep-ph

Birth of colliding beams in Europe, two photon studies at Adone

This article recalls the birth of the first electron-positron storage ring AdA, and the construction of the higher energy collider ADONE, where early photon-photon collisions were observed. The events which led the Austrian physicist Bruno Touschek to propose and construct AdA will be recalled, starting with early work on the Wideroe's betatron during World War II, up to the construction of ADONE, and the theoretical contribution to radiative corrections to electron-positron collisions.

physics.hist-ph

Bruno Touschek, from Betatrons to Electron-positron Colliders

Bruno Touschek's life as a physicist spanned the period from World War II to the 1970s. He was a key figure in the developments of electron-positron colliders, storage rings, and gave important contributions to theoretical high energy physics. Storage rings, initially developed for high energy physics, are being widely used in many countries as synchrotron radiation sources and are a tool for research in physics, chemistry, biology environmental sciences and cultural heritage studies. We describe Touschek's life in Austria, where he was born, Germany, where he participated to the construction of a betatron during WWII, and Italy, where he proposed and led to completion the first electron-positron storage ring in 1960, in Frascati. We highlight how his central European culture influenced his life style and work, and his main contributions to physics, such as the discovery of the Touschek effect and beam instabilities in the larger storage ring ADONE.

physics.hist-ph