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 What is the iε for the S-matrix? by Holmfridur Sigridar Hannesdottir , Sebastian Mizera English | PDF,EPUB | 2023 | 165 Pages | ISBN : 303118257X | 17.3 MB This book provides a modern perspective on the analytic structure of scattering amplitudes in quantum field theory, with the goal of understanding and exploiting consequences of unitarity, causality, and locality. It focuses on the question: Can the S-matrix be complexified in a way consistent with causality? The affirmative answer has been well understood since the 1960s, in the case of 2→2 scattering of the lightest particle in theories with a mass gap at low momentum transfer, where the S-matrix is analytic everywhere except at normal-threshold branch cuts. We ask whether an analogous picture extends to realistic theories, such as the Standard Model, that include massless fields, UV/IR divergences, and unstable particles. Especially in the presence of light states running in the loops, the traditional iε prescription for approaching physical regions might break down, because causality requirements for the individual Feynman diagrams can be mutually incompatible. We demonstrate that such analyticity problems are not in contradiction with unitarity. Instead, they should be thought of as finite-width effects that disappear in the idealized 2→2 scattering amplitudes with no unstable particles, but might persist at higher multiplicity. To fix these issues, we propose an iε-like prescription for deforming branch cuts in the space of Mandelstam invariants without modifying the analytic properties of the physical amplitude.  Peter Probst, "What Is African Art?: A Short History" English | ISBN: 022679301X | 2022 | 248 pages | PDF | 30 MB A history of the evolving field of African art.  Well-being in the Workplace : A Guide to Resilience for Individuals and Teams by Sarah Cook English | 2021 | ISBN: 1787783162 | 108 Pages | True PDF | 1.12 MB  Web Development from Beginner to Paid Professional: Coding Challenges and solutions - The smartest way to learn html and css English | 2022 | ASIN: B09Z7QYTKG | 77 Pages | PDF EPUB | 1.3 MB  Web Development from Beginner to Paid Professional: Build your portfolio as you learn Html5, CSS and jаvascript step by step with support English | 2022 | ASIN: B0B22PSFMT | 178 Pages | PDF EPUB | 2 MB  Web Development from Beginner to Paid Professional: Build your portfolio as you learn Html5, CSS and jаvascript step by step with support English | 2022 | ASIN: B09XWK7BXW | 197 Pages | PDF EPUB | 4 MB  Water and Ions As the Conditions Necessary for the Presence of Life: The Secret History of Life by Raul Cuero, Author; English | 2023 | ISBN: 1527590607 | 124 pages | True PDF | 9.52 MB  C Franklin Brookhart, "Washed and Well-Fed" English | ISBN: 1725287420 | 2021 | 102 pages | EPUB | 2 MB The sacraments of baptism and eucharist do not occupy a back corner of Christian life. In this book your will discover both a theology of the sacraments and also a way to live into them. The result will be your life transformed by a closer and more durable relation with Jesus Christ. That's because the sacraments change everything.  Wagtail CMS in Action With Django and Python (MEAP V04) English | 2022 | ISBN: 9781633439016 | 135 pages | PDF,EPUB | 4.74 MB Upgrade your content management system! Build real-world websites, blogs, and e-commerce web apps with the Python-based Wagtail CMS.  Wage and Well-being: Toward Sustainable Livelihood by Stuart C. Carr English | PDF,EPUB | 2023 | 278 Pages | ISBN : 3031193008 | 15.8 MB This book examines the links between work wage and wellbeing, drawing on the new specialism of Humanitarian Work Psychology and the United Nations Sustainable Development Goals (SDGs). Humanitarian work psychology foregrounds people before profit, not wages before people. It resonates with the SDGs through the Decent Work Agenda, a policy program that stresses a number of humanitarian concerns: standards and rights at work, employment creation and enterprise development, social protection and social dialogue. |
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