1,721,092 research outputs found
Deconfinement phase transition in one-flavor QCD
No full textWe present a study of the deconfinement phase transition of one-flavor QCD using the multiboson algorithm. The mass of the Wilson fermions relevant for this study is moderately large and the non-Hermitian multiboson method is a superior simulation algorithm. Finite-size scaling is studied on lattices of size (Formula presented) (Formula presented), and (Formula presented). The behaviors of the peak of the Polyakov loop susceptibility, the deconfinement ratio, and the distribution of the norm of the Polyakov loop are all characteristic of a first-order phase transition for heavy quarks. As the quark mass decreases, the first-order transition gets weaker and turns into a crossover. To investigate finite-size scaling on larger spatial lattices we use an effective action in the same universality class as QCD. This effective action is constructed by replacing the fermionic determinant with the Polyakov loop identified as the most relevant (Formula presented)-symmetry-breaking term. Higher-order effects are incorporated in an effective (Formula presented)-breaking field h, which couples to the Polyakov loop. Finite-size scaling determines the value of h where the first-order transition ends. Our analysis at the end point (Formula presented) indicates that the effective model and thus QCD are consistent with the universality class of the three-dimensional Ising model. Matching the field strength at the end point (Formula presented) to the (Formula presented) values used in the dynamical quark simulations we estimate the end point (Formula presented) of the first-order phase transition. We find (Formula presented) which corresponds to a quark mass of about 1.4 GeV. © 1999 The American Physical Society
Thermodynamics of 1-flavor QCD
No full textWe present first results, for heavy to moderate quark masses, of a study of thermodynamic properties of 1-flavor QCD, using the multiboson algorithm
Hadron structure from lattice QCD - outlook and future perspectives
No full textWe review results on hadron structure using lattice QCD simulations with pion masses close or at the physical value.We pay particular attention to recent successes on the computation of the mass of the low-lying baryons and on the challenges involved inevaluating energies of excited states and resonance parameters, as well as, in studies of nucleon structure
Nucleon structure from lattice QCD – recent achievements and perspectives
Full text linkWe present recent developments in lattice QCD simulations as applied in the study of hadron structure. We discuss the challenges and perspectives in the evaluation of benchmark quantities such as the nucleon axial charge and the isovector parton momentum fraction, as well as, in the computation of the nucleon σ-terms, which involve the calculation of disconnected quark loop contributions
Novel applications of Lattice QCD: Parton Distributions, proton charge radius and neutron electric dipole moment
No full textWe briefly discuss the current status of lattice QCD simulations and review selective results on nucleon observables focusing on recent developments in the lattice QCD evaluation of the nucleon form factors and radii, parton distribution functions and their moments, and the neutron electric dipole moment. Nucleon charges and moments of parton distribution functions are presented using simulations generated at physical values of the quark masses, while exploratory studies are performed for the parton distribution functions and the neutron electric dipole moment at heavier than physical value of the pion mass
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Towards the determination of the 3-dimensional structure of the proton using lattice QCD simulations
Full text linkState-of-the-art lattice QCD simulations enable the evaluation of nucleon
form factors and Mellin moments with controlled systematics, yielding results
with unprecedented accuracy. At the same time, new theoretical approaches are
allowing the direct computation of nucleon generalized parton distributions. We
review recent lattice QCD results on these quantities that are paving the way
for extracting a wealth of information on the 3-dimensional structure of the
nucleon.Comment: Two figures updated and typos corrected. 8 pages and 7 figures.
Invited talk at the 16th edition of the "International Conference on
Meson-Nucleon Physics and the Structure of the Nucleon" (MENU 2023), October
16-20, 2023, Institute for Nuclear Physics of the Johannes Gutenberg
University of Mainz, Germany. arXiv admin note: text overlap with
arXiv:2309.0577
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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