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Nuclear Forces from Lattice Quantum Chromodynamics

Savage, Martin J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 18/09/2013
Relevância na Pesquisa
55.87%
A century of coherent experimental and theoretical investigations have uncovered the laws of nature that underly nuclear physics. The standard model of strong and electroweak interactions, with its modest number of input parameters, dictates the dynamics of the quarks and gluons - the underlying building blocks of protons, neutrons, and nuclei. While the analytic techniques of quantum field theory have played a key role in understanding the dynamics of matter in high energy processes, they encounter difficulties when applied to low-energy nuclear structure and reactions, and dense systems. Expected increases in computational resources into the exa-scale during the next decade will provide the ability to numerically compute a range of important strong interaction processes directly from QCD with quantifiable uncertainties using the technique of Lattice QCD. These calculations will refine the chiral nuclear forces that are used as input into nuclear many-body calculations, including the three- and four-nucleon interactions. I discuss the state-of-the-art Lattice QCD calculations of quantities of interest in nuclear physics, progress that is expected in the near future, and the impact upon nuclear physics.; Comment: Presentation at the International Conference on Nuclear Theory in the Supercomputing Era -2013...

Initiative in Nuclear Theory at the Variable Energy Cyclotron Centre

Srivastava, D. K.; Alam, J.; Basu, D. N.; Chaudhuri, A. K.; De, J. N.; Krishan, K.; Pal, S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/06/2005
Relevância na Pesquisa
65.86%
We recall the path breaking contributions of the nuclear theory group of the Variable Energy Cyclotron Centre, Kolkata. From a beginning of just one person in 1970s, the group has steadily developed into a leading group in the country today, with seminal contributions to almost the entire range of nuclear physics, viz., low energy nuclear reactions, nuclear structure, deep inelastic collisions, fission, liquid to gas phase transitions, nuclear matter, equation of state, mass formulae, neutron stars, relativistic heavy ion collisions, medium modification of hadron properties, quark gluon plasma, and cosmology of early universe.; Comment: Lecture given at the special session, "Reflections" during Workshop on Changing Scales in Nuclear Physics at Variable Energy Cyclotron Centre, Kolkata during June 14-15, 2005 to honour Prof. Bikash Sinha on his 60th birth day. 48 pages, 12 figures

Nuclear forces and ab initio calculations of atomic nuclei

Meißner, Ulf-G.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/01/2014
Relevância na Pesquisa
55.86%
Nuclear forces and the nuclear many-body problem have been some of Gerry Brown's main topics in his so productive life as a theoretical physicist. In this talk, I outline how Gerry's work laid the foundations of the modern theory of nuclear forces and ab initio calculations of atomic nuclei. I also present some recent developments obtained in the framework of nuclear lattice simulations.; Comment: Contribution to "45 years of nuclear theory at Stony Brook: a tribute to Gerald E. Brown", uses elsarticle.cls

Interactions, symmetry breaking, and effective fields from quarks to nuclei. (A primer in nuclear theory)

Dobaczewski, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 22/01/2003
Relevância na Pesquisa
65.8%
An introduction to nuclear theory is given starting from the quantum chromodynamics foundations for quark and gluon fields, then discussing properties of pions and nucleons, interactions between nucleons, structure of the deuteron and light nuclei, and finishing at the description of heavy nuclei. It is shown how concepts of different energy and size scales and ideas related to effective fields and symmetry breaking, enter our description of nuclear systems.; Comment: 43 pages, 10 EPS figures. Lecture notes at the Joliot-Curie International School, Maubuisson 2002

Uncertainty analysis and order-by-order optimization of chiral nuclear interactions

Carlsson, B. D.; Ekström, A.; Forssén, C.; Strömberg, D. Fahlin; Jansen, G. R.; Lilja, O.; Lindby, M.; Mattsson, B. A.; Wendt, K. A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.82%
Chiral effective field theory (chiEFT) provides a systematic approach to describe low-energy nuclear forces. Moreover, chiEFT is able to provide well-founded estimates of statistical and systematic uncertainties -- although this unique advantage has not yet been fully exploited. We fill this gap by performing an optimization and statistical analysis of all the low-energy constants (LECs) up to next-to-next-to-leading order. Our optimization protocol corresponds to a simultaneous fit to scattering and bound-state observables in the pion-nucleon, nucleon-nucleon, and few-nucleon sectors, thereby utilizing the full model capabilities of chiEFT. We study the effect on other observables by demonstrating error-propagation methods that can easily be adopted by future works. We employ mathematical optimization and implement automatic differentiation to attain efficient and machine-precise first- and second-order derivatives of the objective function with respect to the LECs. We use power-counting arguments to estimate the systematic uncertainty that is inherent to chiEFT and we construct chiral interactions at different orders with quantified uncertainties. Statistical error propagation is compared with Monte Carlo sampling showing that statistical errors are in general small compared to systematic ones. In conclusion...

Modeling nuclear parton distribution functions

Honkanen, H.; Strikman, M.; Guzey, V.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.83%
The presence of nuclear medium and collective phenomena which involve several nucleons modify the parton distribution functions of nuclei (nPDFs) compared to those of a free nucleon. These modifications have been investigated by different groups using global analyses of high energy nuclear reaction world data resulting in modern nPDF parametrizations with error estimates, such as EPS09(s), HKN07 and nDS. These phenomenological nPDF sets roughly agree within their uncertainty bands, but have antiquarks for large-$x$ and gluons for the whole $x$-range poorly constrained by the available data. In the kinematics accessible at the LHC this has negative impact on the interpretation of the heavy-ion collision data, especially for the $p + A$ benchmarking runs. The EMC region is also sensitive to the proper definition of $x$, where the nuclear binding effects have to be taken into account, and for heavy nuclei one also needs to take into account that a fraction of the nucleus momentum is carried by the equivalent photons which modifies the momentum sum rule. We study how these effects affect the predictions for the nuclear modification ratios at the LHC kinematics using a model where we combine theoretical input for the leading twist nuclear shadowing (the FGS model) and the EKS98s/EPS09s nPDF set where the spatial dependence is formulated as a power series of the nuclear thickness functions $T_A$.; Comment: Prepared for the proceedings of International Conference on Nuclear Theory in the Supercomputing Era - 2013; revised version

A Vision for Nuclear Theory: Report to NSAC

Carlson, J.; Holstein, B.; Ji, X. D.; McLaughlin, G.; Müller, B.; Nazarewicz, W.; Rajagopal, K.; Roberts, W.; Wang, X. -N.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 18/11/2003
Relevância na Pesquisa
65.89%
This is the report of the NSAC Subcommittee on Nuclear Theory in response to a charge by the funding agencies to review and evaluate current NSF and DOE supported efforts in nuclear theory and identify strategic plans to ensure a strong U.S. nuclear theory program under various funding scenarios.; Comment: Report of the NSAC Nuclear Theory Subcommittee

Novel effects of electromagnetic interaction on the correlation of nucleons in nuclear matter

Chen, Ji-sheng; Li, Jia-rong; Jin, Meng
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.82%
The electromagnetic(EM) interactions between charged protons on the correlations of nucleons are discussed by introducing the Anderson-Higgs mechanism of broken U(1) EM symmetry into the relativistic nuclear theory with a parametric photon mass. The non-saturating Coulomb force contribution is emphasized on the equation of state of nuclear matter with charge symmetry breaking(CSB) at finite temperature and the breached $^1S_0$ pairing correlations of proton-proton and neutron-neutron. The universal properties given by an order parameter field with a non-zero vacuum expectation value (VEV) nearby phase transition are explored within the mean field theory(MFT) level. This mechanism can be extended to the charged or charge neutralized strongly coupling multi-components system for the discussion of binding or pairing issues.; Comment: 6 pages, 3 figues, revised according to comments; improved with typos corrected and updated references added; final published version in Phys. Lett. B

Living on the edge of stability, the limits of the nuclear landscape

Forssen, C.; Hagen, G.; Hjorth-Jensen, M.; Nazarewicz, W.; Rotureau, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/12/2012
Relevância na Pesquisa
55.86%
A first-principles description of nuclear systems along the drip lines presents a substantial theoretical and computational challenge. In this paper, we discuss the nuclear theory roadmap, some of the key theoretical approaches, and present selected results with a focus on long isotopic chains. An important conclusion, which consistently emerges from these theoretical analyses, is that three-nucleon forces are crucial for both global nuclear properties and detailed nuclear structure, and that many-body correlations due to the coupling to the particle continuum are essential as one approaches particle drip lines. In the quest for a comprehensive nuclear theory, high performance computing plays a key role.; Comment: Contribution to proceedings of Nobel Symposium 152: Physics with radioactive beams, June 2012, Gothenburg, Sweden

Annual Report for the Department of Energy: 1999-2000, Nuclear Theory Group at the University of Washington

Bulgac, A.; Henley, E. M.; Miller, G. A.; Savage, M. J.; Wilets, L.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 14/07/2000
Relevância na Pesquisa
65.76%
This document is a summary of the physics research carried out by the Nuclear Theory Group at the University of Washington during the last twelve-month period, 1999-2000.; Comment: 33 pages, 5 eps figure, latex

Light Front Nuclear Theory and the HERMES Effect

Miller, Gerald A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/11/2000
Relevância na Pesquisa
55.84%
I discuss the use of light cone variables to compute the nucleonic and mesonic components of nuclear wave functions. A Lagrangian and its energy-momentum tensor $T^{^+\mu}$ is used to define the total momentum operators $P^\mu$. The aim is to use wave functions, expressed in terms of plus-momentum variables, which are used to analyze high energy experiments such as deep inelastic scattering, Drell-Yan production, (e,e') and (p,p') reactions. We discuss infinite nuclear matter within the mean field approximation; finite nuclei using the mean field approximation; nucleon-nucleon scattering, within the one boson exchange approximation; and, infinite nuclear matter including the effects of two-nucleon correlations. Standard good results for nuclear saturation properties are obtained, with a possible improvement in the lowered value, 180 MeV, of the computed nuclear compressibility. In our approach, manifest rotational invariance emerges at the end of the calculation. Thus nuclear physics can be done in a manner in which modern nuclear dynamics can be implemented and symmetries are respected. A salient feature is that $\omega,\sigma$ and $\pi$ mesons are obtained as important constituents. These can contribute coherently to enhance nuclear electroproduction cross sections for longitudinal virtual photons at low $Q^2$...

A way forward in the study of the symmetry energy: experiment, theory, and observation

Horowitz, C. J.; Brown, E. F.; Kim, Y.; Lynch, W. G.; Michaels, R.; Ono, A.; Piekarewicz, J.; Tsang, M. B.; Wolter, H. H.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 22/01/2014
Relevância na Pesquisa
55.84%
The symmetry energy describes how the energy of nuclear matter rises as one goes away from equal numbers of neutrons and protons. This is very important to describe neutron rich matter in astrophysics. This article reviews our knowledge of the symmetry energy from theoretical calculations, nuclear structure measurements, heavy ion collisions, and astronomical observations. We then present a roadmap to make progress in areas of relevance to the symmetry energy that promotes collaboration between the astrophysics and the nuclear physics communities.; Comment: 19 pages, results from first International Collaborations in Nuclear Theory (ICNT) program at NSCL/FRIB, submitted to J. Phys G

Nuclear Theory and Science of the Facility for Rare Isotope Beams

Balantekin, A. B; Carlson, J.; Dean, D. J.; Fuller, G. M.; Furnstahl, R. J.; Hjorth-Jensen, M.; Janssens, R. V. F.; Li, Bao-An; Nazarewicz, W.; Nunes, F. M.; Ormand, W. E.; Reddy, S.; Sherrill, B. M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/01/2014
Relevância na Pesquisa
65.93%
The Facility for Rare Isotope Beams (FRIB) will be a world-leading laboratory for the study of nuclear structure, reactions and astrophysics. Experiments with intense beams of rare isotopes produced at FRIB will guide us toward a comprehensive description of nuclei, elucidate the origin of the elements in the cosmos, help provide an understanding of matter in neutron stars, and establish the scientific foundation for innovative applications of nuclear science to society. FRIB will be essential for gaining access to key regions of the nuclear chart, where the measured nuclear properties will challenge established concepts, and highlight shortcomings and needed modifications to current theory. Conversely, nuclear theory will play a critical role in providing the intellectual framework for the science at FRIB, and will provide invaluable guidance to FRIB's experimental programs. This article overviews the broad scope of the FRIB theory effort, which reaches beyond the traditional fields of nuclear structure and reactions, and nuclear astrophysics, to explore exciting interdisciplinary boundaries with other areas. \keywords{Nuclear Structure and Reactions. Nuclear Astrophysics. Fundamental Interactions. High Performance Computing. Rare Isotopes. Radioactive Beams.; Comment: 20 pages...

Nuclear Reactions from Lattice QCD

Briceño, Raúl A.; Davoudi, Zohreh; Luu, Thomas C.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.9%
One of the overarching goals of nuclear physics is to rigorously compute properties of hadronic systems directly from the fundamental theory of strong interactions, Quantum Chromodynamics (QCD). In particular, the hope is to perform reliable calculations of nuclear reactions which will impact our understanding of environments that occur during big bang nucleosynthesis, the evolution of stars and supernovae, and within nuclear reactors and high energy/density facilities. Such calculations, being truly ab initio, would include all two-nucleon and three- nucleon (and higher) interactions in a consistent manner. Currently, lattice QCD provides the only reliable option for performing calculations of some of the low- energy hadronic observables. With the aim of bridging the gap between lattice QCD and nuclear many-body physics, the Institute for Nuclear Theory held a workshop on Nuclear Reactions from Lattice QCD on March 2013. In this review article, we report on the topics discussed in this workshop and the path planned to move forward in the upcoming years.; Comment: 35 pages, 13 figures, 1 table, review article for the "Nuclear Reactions from Lattice QCD" workshop hosted by the Institute for Nuclear Theory on March 2013; version 2 includes updated references and extended discussion of previous work

Light Front Nuclear Theory

Miller, Gerald A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 06/09/2001
Relevância na Pesquisa
55.85%
High energy scattering experiments involving nuclei are typically analyzed in terms of light front variables. The desire to provide realistic,relativistic wave functions expressed in terms of these variables led me to try to use light front dynamics to compute nuclear wave functions. Here calculations of infinite nuclear matter in the mean field approximation and also in a light front version of Bruckner theory which includes NN correlations are reviewed. Applications of these wave functions to nuclear deep inelastic scattering and Drell-Yan processes are discussed. We find that relativistic mean field theory produces no EMC binding effect.; Comment: For Proceedings of 3rd International Conference on Perspectives in Hadronic Physics, May 2001

Challenges for Modeling Nuclear Structure: Are the Proton and Neutron Masses and A-body Interactions Relevant?

Gueorguiev, V. G.; Navratil, P.; Vary, J. P.; Draayer, J. P.; Pan, F.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/11/2010
Relevância na Pesquisa
55.86%
We discuss some of the challenges that future nuclear modeling may face in order to improve the description of the nuclear structure. One challenge is related to the need for A-body nuclear interactions justified by various contemporary nuclear physics studies. Another challenge is related to the discrepancy in the NNN contact interaction parameters for 3He and 3H that suggests the need for accurate proton and neutron masses in the future precision calculations. MSC2010 Classification: 17B81 Applications to physics, 17B80 Applications to integrable systems, 81R12 Relations with integrable systems, 81V70 Many-body theory, 81V35 Nuclear physics, 81U15 Exactly and quasi-solvable systems, 82B23 Exactly solvable models; Bethe ansatz.; Comment: 13 pages, 6 figures, Contribution to the XXIX International Workshop on Nuclear Theory, June 20 - 26, 2010, Rila Mountains, Bulgaria

Many-body interactions and nuclear structure

Hjorth-Jensen, M.; Dean, D. J.; Hagen, G.; Kvaal, S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 07/03/2010
Relevância na Pesquisa
55.9%
This article presents several challenges to nuclear many-body theory and our understanding of the stability of nuclear matte r. In order to achieve this, we present five different cases, starting with an idealized toy model. These cases expose problems that need to be understood in order to match recent advances in nuclear theory with current experimental programs in low-energy nuclear physics. In particular, we focus on our current understanding, or lack thereof, of many-body forces, and how they evolve as functions of the number of particles . We provide examples of discrepancies between theory and experiment and outline some selected perspectives for future research directions.; Comment: 26 pages and 6 figures, IOP latex style. Subimtted to Journal of Physics G, Focus issue on open problems in Nuclear structure theory

The Nuclear Force Problem: Is the Never-Ending Story Coming to an End?

Machleidt, R.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 18/09/2006
Relevância na Pesquisa
55.88%
The attempts to find the right (underlying) theory for the nuclear force have a long and stimulating history. Already in 1953, Hans Bethe stated that "more man-hours have been given to this problem than to any other scientific question in the history of mankind". In search for the nature of the nuclear force, the idea of sub-nuclear particles was created which, eventually, generated the field of particle physics. I will review this productive history of hope, error, and desperation. Finally, I will discuss recent ideas which apply the concept of an effective field theory to low-energy QCD. There are indications that this concept may provide the right framework to properly understand nuclear forces.; Comment: 10 pages, 2 figures, talk at XXV International Workshop on Nuclear Theory, June 26-July 1, 2005, Rila Mountains, Bulgaria

Pion Excess, Nuclear Correlations, and the Interpretation of ($\vec p, \vec n$) Spin Transfer Experiments

Koltun, Daniel S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 16/09/1997
Relevância na Pesquisa
55.85%
Conventional theories of nuclear interactions predict a net increase in the distribution of virtual pions in nuclei relative to free nucleons. Analysis of data from several nuclear experiments has led to claims of evidence against such a pion excess. These conclusions are usually based on a collective theory (RPA) of the pions, which may be inadequate. The issue is the energy dependence of the nuclear response, which differs for theories with strong NN correlations from the RPA predictions. In the present paper, information about the energy dependence is extracted from sum rules, which are calculated for such a correlated, noncollective nuclear theory. The results lead to much reduced sensitivity of nuclear reactions to the correlations that are responsible for the pion excess. The primary example is $(\vec p,\vec n)$ spin transfer, for which the expected effects are found to be smaller than the experimental uncertainties. The analysis has consequences for Deep Inelastic Scattering (DIS) experiments as well.; Comment: 16 pages, LaTeX, no figures, submitted to Phys. Rev. C

NUCLEAR THEORY WHITE PAPER 1995

Bertsch, G.; Mueller, B.; Negele, J.; Friar, J.; Pandharipande, V.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.82%
We review the accomplishments of nuclear theory during the past five years and identify the future challenges and research opportunities. [Final, substantially revised version of the nuclear theory white paper]; Comment: 33 pages, LaTeX, 6 figures in uuencoded PostScript files