Observed Behavior of Highly Inelastic Electron-Proton Scattering

Breidenbach, M.; Friedman, J.; Kendall, Henry W.; Bloom, E. D.; Coward, D. H.; DeStaebler, H.; Drees, J.; Mo, Luke W.; Taylor, Richard E.

doi:10.1103/physrevlett.23.935

Cited by 580 publications

(371 citation statements)

References 17 publications

(5 reference statements)

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“…These were verified by experiments at SLAC in 1969 and provided strong evidence for a particle interpretation of quarks [56,57].…”

Section: Brief History Of Quantum Chromodynamicsmentioning

confidence: 58%

Multi-Hadron Observables from Lattice Quantum Chromodynamics

Hansen¹

2014

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Multi-Hadron Observables from Lattice Quantum Chromodynamics Maxwell T. HansenChair of the Supervisory Committee:Professor Stephen R. Sharpe Department of PhysicsWe describe formal work that relates the finite-volume spectrum in a quantum field theory to scattering and decay amplitudes. This is of particular relevance to numerical calculations performed using Lattice Quantum Chromodynamics (LQCD). Correlators calculated using LQCD can only be determined on the Euclidean time axis. For this reason the standard method of determining scattering amplitudes via the Lehmann-Symanzik-Zimmermann reduction formula cannot be employed. By contrast, the finite-volume spectrum is directly accessible in LQCD calculations. Formalism for relating the spectrum to physical scattering observables is thus highly desirable.In this thesis we develop tools for extracting physical information from LQCD for four types of observables. First we analyze systems with multiple, strongly-coupled two-scalar channels. Here we accommodate both identical and nonidentical scalars, and in the latter case allow for degenerate as well as nondegenerate particle masses. Using relativistic field theory, and summing to all orders in perturbation theory, we derive a result relating the finite-volume spectrum to the two-to-two scattering amplitudes of the coupled-channel theory. This generalizes the formalism of Martin Lüscher for the case of single-channel scattering. Second we consider the weak decay of a single particle into multiple, coupled two-scalar channels. We show how the finite-volume matrix element extracted in LQCD is related to matrix elements of asymptotic two-particle states, and thus to decay amplitudes. This generalizes work by Laurent Lellouch and Martin Lüscher. Third we extend the method for extracting matrix elements by considering currents which insert energy, momentum and angular momentum. This allows one to extract transition matrix elements and form factors from LQCD. Finally we look beyond two-particle systems to those with three-particles in asymptotic states. Working again to all orders in relativistic field theory, we derive a relation between the spectrum and an infinite-volume three-to-three scattering quantity. This final analysis is the most complicated of the four, because the all-orders summation is more difficult for this system, and also because a number of new technical issues arise in analyzing the contributing diagrams.

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“…These were verified by experiments at SLAC in 1969 and provided strong evidence for a particle interpretation of quarks [56,57].…”

Section: Brief History Of Quantum Chromodynamicsmentioning

confidence: 58%

Multi-Hadron Observables from Lattice Quantum Chromodynamics

Hansen¹

2014

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“…Mas, em 1969 no SLAC foi feita uma descoberta inesperada. Estudos de processos de espalhamento inelástico profundo (grande momento transferido) como e − -p, e − -dêuteron (queé o núcleo do deutério, ou hidrogênio pesado, e está formado por um próton e um nêutron) e múons em prótons e dêuteron, foi observado um comportamento diferente do esperado, nas seções de choque chamado de scaling [73][74][75] (usaremos aqui a palavra em inglês [76], constituintes pontuais, dentro dos núcleons. Estes pártons seriam em um número arbitrariamente grande segundo Feynman.…”

Section: Os Experimentos Da Colaboração Gargamelleunclassified

A descoberta das correntes neutras das interações fracas

Fortes¹,

Tijero²,

Pleitez³

2007

Rev. Bras. Ens. Fis.

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Neste artigo fazemos uma crônica sobre a descoberta das correntes neutras fracas por dois grupos experimentais independentes. Consideramos também um pouco da história das correntes neutras para contextualizar melhor essa descoberta que foi decisiva para a posterior confirmação do modelo padrão eletrofraco. Esta descoberta deixa clara a dificuldade de considerar os resultados experimentais como sendo completamente independentes da teoria. Palavras-chave: correntes neutras, bósons Z, modelo eletrofraco.In this paper we narrate the discovery of the weak neutral currents by two independent experimental collaborations. We also give a brief review of the history of the neutral currents in order to give a clear description of the context of that discovery which was decisive for a later confirmation of the electroweak standard model. This discovery shows the difficulty for considering the experimental results as being completely independent of the theory. Keywords: neutral currents, Z boson, electroweak model. IntroduçãoNormalmente, acredita-se que exista uma maneira clara e livre de ambigüidades de diferenciar "fatos observacionais" (ou simplesmente "fatos") por um lado, e hipóteses teóricas por outro. Estasúltimas seriam "especulativas" e podem ser confirmadas ou refutadas, já os "fatos" experimentais são claros, sem ambigüidades e falam por si mesmos. No entanto, essa diferenciação entre hipóteses teóricas e experimentais nem sempreé trivial. Existem situações em que a teoria ajuda a definir o que seriam considerados "fatos". Em outras palavras, fica difícil,às vezes, distinguir se uma hipóteseé "factual" ou teórica. O historiador da ciência Peter Galison coloca a situação assim: nem sempreé fácil saber quando deve ser finalizado um experimento [1,2]. Como exemplos, podemos colocar as observações da violação da paridade nas interações fracas [3, 4] e das correntes neutras fracas. No presente artigo vamos considerar em detalhe apenas o segundo caso.O chamado modelo padrão (MP) das partículas fundamentais e suas interações (a nuclear forte, a nuclear fraca, e a eletromagnética)é a teoria que descreve os fenômenos subnucleares e tem sido amplamente confirmada pelos dados experimentais nasúltimas décadas.Esse modelo e a teoria da relatividade de Einstein constituem dois dos pilares fundamentais da nossa compreensão científica da Natureza. O modelo está baseado em simetrias de gauge ou de calibre locais não Abelianas.O MP tem duas partes, a chamada cromodinâmica quântica (QCD pela sigla em inglês) e a parte eletrofraca que aqui chamamos MPE. Esteúltimo modelo inclui o chamado mecanismo de Higgs ou quebra espontânea de simetria, que tem como conseqüência a existência (ainda não confirmada) de um escalar elementar, o chamado bóson de Higgs. A primeira evidência de que o MPE estava correto foi dada pela observação, por duas equipes de físicos experimentais, das correntes neutras fracas que eram previstas por esse modelo. Essas experiências são um exemplo claro da falsificação de uma teoria. Caso esse tipo de correntes não ti...

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“…69 See Friedman 1991, footnote 3;Kendall 1991, 609;Taylor 2001, 233. 70 Breidenbach et al 1969;and Miller et al 1972. Note that the analysis in the first paper was restricted to relatively smaller values of and v. The scaling feature of the cross section data was later verified for larger values by Miller et al 1972.…”

Section: The Deep-inelastic Electron-proton Scattering Experimentsmentioning

confidence: 99%

“…The upper curves represent inelastic cross-section measurements, and the lowest one represents the data from elastic scattering. From Breidenbach et al 1969. The historical context in which the DIS experiments were launched indicates that the MIT-SLAC collaboration did not take into account Bjorken's 1967 result (concerning the backward electronproton inelastic scattering) that was the only theoretical result relevant to the aims of the DIS 64 Friedman (personal communication, October 4, 2007). 65 Bloom et al 1969.…”

Section: The Deep-inelastic Electron-proton Scattering Experimentsmentioning

confidence: 99%

The Strong and Weak Senses of Theory-Ladenness of Experimentation: Theory-Driven versus Exploratory Experiments in the History of High-Energy Particle Physics

Karaca¹

2013

Sci Context

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ArgumentIn the theory-dominated view of scientific experimentation, all relations of theory and experiment are taken on a par; namely, that experiments are performed solely to ascertain the conclusions of scientific theories. As a result, different aspects of experimentation and of the relation of theory to experiment remain undifferentiated. This in turn fosters a notion of theoryladenness of experimentation (TLE) that is too coarse-grained to accurately describe the relations of theory and experiment in scientific practice. By contrast, in this article, I suggest that TLE should be understood as an umbrella concept that has different senses. To this end, I introduce a three-fold distinction among the theories of high-energy particle physics (HEP) as background theories, model theories and phenomenological models. Drawing on this categorization, I contrast two types of experimentation, namely, "theory-driven" and "exploratory" experiments, and I distinguish between the "weak" and "strong" senses of TLE in the context of scattering experiments from the history of HEP. This distinction enables to identify the exploratory character of the deep-inelastic electron-proton scattering experimentsperformed at the Stanford Linear Accelerator Center (SLAC) between the years 1967 and 1973-thereby shedding light on a crucial phase of the history of HEP, namely, the discovery of "scaling", which was the decisive step towards the construction of quantum chromo-dynamics (QCD) as a gauge theory of strong interactions.

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Observed Behavior of Highly Inelastic Electron-Proton Scattering

Cited by 580 publications

References 17 publications

Multi-Hadron Observables from Lattice Quantum Chromodynamics

Multi-Hadron Observables from Lattice Quantum Chromodynamics

A descoberta das correntes neutras das interações fracas

The Strong and Weak Senses of Theory-Ladenness of Experimentation: Theory-Driven versus Exploratory Experiments in the History of High-Energy Particle Physics

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