Interpretation of Experiments on the Photo-nuclear Effect in Heavy Elements PDF Download

Author: L. Eyges
Publisher:
ISBN:
Category : Heavy elements
Languages : en
Pages : 36

View

Book Description

Author: National Research Council
Publisher: National Academies Press
ISBN: 0309173663
Category : Science
Languages : en
Pages : 222

View

Book Description
Dramatic progress has been made in all branches of physics since the National Research Council's 1986 decadal survey of the field. The Physics in a New Era series explores these advances and looks ahead to future goals. The series includes assessments of the major subfields and reports on several smaller subfields, and preparation has begun on an overview volume on the unity of physics, its relationships to other fields, and its contributions to national needs. Nuclear Physics is the latest volume of the series. The book describes current activity in understanding nuclear structure and symmetries, the behavior of matter at extreme densities, the role of nuclear physics in astrophysics and cosmology, and the instrumentation and facilities used by the field. It makes recommendations on the resources needed for experimental and theoretical advances in the coming decade.

Author:
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 612

View

Book Description

Author:
Publisher:
ISBN:
Category : Photonuclear reactions
Languages : en
Pages : 140

View

Book Description

Author: International Atomic Energy Agency
Publisher:
ISBN:
Category : Photonuclear reactions
Languages : en
Pages : 416

View

Book Description

Author: B. W. Sargent
Publisher:
ISBN:
Category : Neutron sources
Languages : en
Pages : 8

View

Book Description

Author: Anthony J. Tropiano
Publisher:
ISBN:
Category : Nuclear forces (Physics)
Languages : en
Pages : 0

View

Book Description
Low-energy nuclear physics encompasses the physics of many-body systems of protons and neutrons (nucleons) ranging from atomic nuclei to neutron stars. Experimental facilities, such as the Facility of Rare Isotope Beams (FRIB), seek to answer overarching questions central to our understanding of atomic nuclei, astrophysics, and fundamental symmetries, such as the origin of heavy elements. Theoretical approaches face the challenge of describing this wide range of physics starting from the force between nucleons. Traditionally, low-energy nuclear theory is split into structure and reaction theory, where the former deals with the static properties of nuclei and the latter with dynamic nuclear processes. Understanding the interplay of reaction and structure theory is critical for reliable predictions and analysis of FRIB experiments. The renormalization group (RG) allows for consistent treatments of reaction and structure. RG transformations continuously shift the resolution scale of structure and reaction components (i.e., wave functions and reaction operators) under a specified scheme, where the resolution scale corresponds to the largest momentum of low-energy wave functions, and the scheme reflects the details of the starting Hamiltonian and RG implementation. Observable quantities are invariant under RG transformations, though structure and reaction components individually depend on the RG resolution scale and scheme. We can take advantage of this latter RG dependence by shifting the resolution scale to make complicated problems feasible. RG transformations decouple low- and high-energy scales in nuclear interactions, facilitating large-scale nuclear structure approaches that rely on many-body basis expansions. The RG has widely been applied to nuclear structure, but not to nuclear reactions or the combination of the two. RG transformations can facilitate nuclear reaction approaches by simplifying initial and final states in transition matrix elements, where RG-transformed reaction operators gain induced many-body contributions. Process-independent quantities (e.g., momentum distributions) can be extracted from experiment via a factorization of nuclear structure components and the reaction operators (the probe), but as a result of factorization, are scale and scheme dependent. The RG provides a natural tool for handling this scale and scheme dependence, which is crucial for interpreting experiments and comparing extracted quantities to theory. This thesis demonstrates each of these points by using the similarity RG (SRG) to transform chiral effective field theory (EFT) or phenomenological interactions, and their associated operators, to low RG resolution. We explore aspects of operator evolution that have particular relevance in the context of scale and scheme dependence of nuclear processes. These aspects include SRG implementations based on the Magnus expansion, band- versus block-diagonal operator flow, universality for chiral EFT interactions and associated operators with different regularization schemes, and the impact of factorization arising from scale separation. We show how the features of short-range correlation phenomenology are cleanly identified at low RG resolution using simple two-body operators and local-density approximations with uncorrelated wave functions, all of which can be systematically generalized. We verify that the experimental consequences to date follow directly at low RG resolution from well-established properties of nuclear interactions. We describe the quasi-deuteron model at low RG resolution and determine the Levinger constant, which is proportional to the ratio of nuclear photo-absorption to that for photo-disintegration of a deuteron. Implications for consistently extracting spectroscopic factors in electron-induced proton knock-out reactions are discussed. The results of this thesis contribute to a broader effort to model processes relevant to FRIB, such as knock-out or break-up reactions.

Author: Christian Segebade
Publisher:
ISBN:
Category : SCIENCE
Languages : en
Pages : 730

View

Book Description

Author: International Atomic Energy Agency
Publisher:
ISBN:
Category : Photonuclear reactions
Languages : en
Pages : 416

View

Book Description

Author: National Research Council
Publisher: National Academies Press
ISBN: 0309260434
Category : Science
Languages : en
Pages : 263

View

Book Description
The principal goals of the study were to articulate the scientific rationale and objectives of the field and then to take a long-term strategic view of U.S. nuclear science in the global context for setting future directions for the field. Nuclear Physics: Exploring the Heart of Matter provides a long-term assessment of an outlook for nuclear physics. The first phase of the report articulates the scientific rationale and objectives of the field, while the second phase provides a global context for the field and its long-term priorities and proposes a framework for progress through 2020 and beyond. In the second phase of the study, also developing a framework for progress through 2020 and beyond, the committee carefully considered the balance between universities and government facilities in terms of research and workforce development and the role of international collaborations in leveraging future investments. Nuclear physics today is a diverse field, encompassing research that spans dimensions from a tiny fraction of the volume of the individual particles (neutrons and protons) in the atomic nucleus to the enormous scales of astrophysical objects in the cosmos. Nuclear Physics: Exploring the Heart of Matter explains the research objectives, which include the desire not only to better understand the nature of matter interacting at the nuclear level, but also to describe the state of the universe that existed at the big bang. This report explains how the universe can now be studied in the most advanced colliding-beam accelerators, where strong forces are the dominant interactions, as well as the nature of neutrinos.