An Introduction to Finite Temperature Quantum Chromodynamics on the Lattice

In these lectures, we introduce finite temperature QCD on the lattice to non-experts of the subject. We first formulate lattice QCD both at zero and finite temperatures. Then a section is devoted to the topic of improved lattice actions which are becoming an essential ingredient of precision studies of QCD on the lattice. We then discuss about finite temperature SU(3) gauge theory, i.e. QCD without dynamical quarks (quenched QCD). Finally, we report recent status of studies in full QCD taking into account the effects of dynamical quarks.Comment: Lectures presented at the 1997 Yukawa International Seminar (YKIS'97) on ``Non-Perturbative QCD --- Structure of the QCD Vacuum ---'', YITP, Kyoto, Japan, 2--12 Dec. 1997. To be published in the proceedings [Prog. Theor. Phys. Suppl.

Progress Towards Petascale Applications in Biology: Status in 2006

Petascale computing is currently a common topic of discussion in the high performance computing community. Biological applications, particularly protein folding, are often given as examples of the need for petascale computing. There are at present biological applications that scale to execution rates of approximately 55 teraflops on a special-purpose supercomputer and 2.2 teraflops on a general-purpose supercomputer. In comparison, Qbox, a molecular dynamics code used to model metals, has an achieved performance of 207.3 teraflops. It may be useful to increase the extent to which operation rates and total calculations are reported in discussion of biological applications, and use total operations (integer and floating point combined) rather than (or in addition to) floating point operations as the unit of measure. Increased reporting of such metrics will enable better tracking of progress as the research community strives for the insights that will be enabled by petascale computing.This research was supported in part by the Indiana Genomics Initiative and the Indiana Metabolomics and Cytomics Initiative. The Indiana Genomics Initiative of Indiana University and the Indiana Metabolomics and Cytomics Initiative of Indiana University are supported in part by Lilly Endowment, Inc. The authors also wish to thank IBM, Inc. for support via Shared University Research Grants and partnerships via IU’s relationship as an IBM Life Sciences Institute of Innovation. Indiana University also thanks the TeraGrid partners; IU’s participation in the TeraGrid is funded by National Science Foundation grant numbers 0338618, 0504075, and 0451237. The early development of this paper was supported by a Fulbright Senior Scholars award from the Council for International Exchange of Scholars (CIES) and the United States Department of State to Dr. Craig A. Stewart; Matthias Mueller and the Technische Universität Dresden were hosts. Many reviewers contributed to the improvement of the ideas expressed in this paper and are gratefully appreciated; Thom Dunning, Robert Germain, Chris Mueller, Jim Phillips, Richard Repasky, Ralph Roskies, and Allan Snavely are thanked particularly for their insights

Construction of Programming Education Environment Using Problem Solving Environment

There are many problems in the research and educational field. Japanese PSE has started in the research area: DEQSOL and NCAS. In Japanese elementary school, programming education will begin this year. After that, the programming education in junior high school and high school are also planned. Thus, the need for programming education is highly expected recently. However, it seems not satisfactory when it comes to self-study environment. In this article, construction of the educational platform ( internet sites ) for the programming beginners will be introduced. This sites includes three programming languages to learn: scratch, C++ and python. Users ( learners ) meets the question first, then answer this question in terms of their programming code. Efficiency in the university class is briefly discussed

Transverse Momentum Spectra at Threshold for Groomed Heavy Quark Jets

We present the transverse momentum spectrum for a heavy hadron at threshold in a groomed jet initiated by a heavy quark. The cross section is doubly differential in the energy fraction of an identified heavy hadron in the jet and its transverse momentum measured with respect to the groomed (recoil free) jet axis. The grooming is implemented using a soft-drop grooming algorithm and helps us in mitigating the effects of Non-Global logarithms and pile up. For the particular case of a $B$ meson, we identify two distinct regimes of the transverse momentum spectrum and develop an EFT within the formalisms of Soft Collineat Effective Theory (SCET) and Heavy Quark Effective Theory (HQET) for each of these regions. We show how each region can be matched smoothly into the other to provide a prediction for the perturbative transverse momentum spectrum. The EFT also predicts the scaling behavior of the leading non-perturbative power corrections and implements a simple shape function to account for hadronization. We work in the threshold region where the heavy hadron carries most of the energy of the jet since in this regime, we have a very good discriminating power between heavy quark and gluon initiated jets. We observe that the shape of the spectrum is independent of the energy of the jet over a large range of transverse momentum. We propose that this spectrum can be used as a probe of evolution for heavy quark TMD fragmentation function. At the same time, it can be treated as a jet substructure observable for probing Quark-Gluon Plasma (QGP).Comment: 26 pages, 7 figure

Distribuciones dependientes de momento transverso para la era del Electron-Ion Collider

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Departamento de Física Teórica, leída el 11/12/2020The physical theory which deals with the strong interactions between quarks and gluons in known as Quantum Chromodynamics (QCD). This theory, together with the ones that deal with electromagnetic and weak interactions (unified in electroweak theory) are combined into the Standard Model (SM). This theory is built in terms of a Lagrangian of quantized fields describing fundamental degrees of freedom, quarks and leptons, and bosons that act as carriers of the cited interactions. One of the more fundamental open questions in QCD is to understand how the observed properties of hadrons are generated by the dynamics of their inner constituents. In order to shed some light on this question physicists use different theoretical approaches from different perspectives, like perturbative QCD, effective field theories, lattice QCD, etc. A very interesting research field to test and understand QCD is the exploration of the multi-dimensional structure of hadrons. The main goal of this field is to reconstruct multi-dimensional images of a hadron investigating the distribution of partons, namely quarks and gluons, inside it. In this way, issues such as the role of quarks and gluons in generating the nucleon’s spin or partonic angular momentum can be investigated. There is a high interest into hadron structure in the experimental community, with important facilities such JLab, DESY, BNL, CERN, KEK. Also, the LHC can help a lot in this field, especially to understand the role of gluons inside the protons. Recently, the US government has approved the construction of a new accelerator, the Electron-Ion Collider (EIC) at BNL. Part of the predictions given in this thesis are suitable to be tested in this new accelerator. A very interesting type of observables that can give information about hadron structure are the ones with non-vanishing transverse momentum dependence. This interest was already there in the first years after the establishment of QCD as a fundamental theory of strong interactions [1–5]. These observables are very interesting for hadron colliders and have very relevant impact on, e.g., the study of Higgs boson production and the search for physics Beyond Standard Model. A crucial point to deal with these type of processes is obtaining well defined factorization theorems and resumming large logarithmic contributions to perform phenomenological analyses. A large amount of work has been done to establish factorization theorems with un-integrated transverse momentum for very relevant processes as Drell-Yan production (proton-proton collision leading to a pair of leptons in the final state) or semi-inclusive deep inelastic scattering (electron-proton collisions leading to a hadron in the final state) [6–17]. In general terms, a factorized cross section is written in terms of a hard factor that includes all the high-energy physics and two objects that include information about the distribution of partons inside the hadrons in the process. These elements are known as transverse momentum dependent parton distribution functions (TMDPDFs)...La teoría física que se ocupa de las interacciones fuertes entre quarks y gluones se conoce como la Cromodinámica Cuántica (QCD por sus siglas en inglés). Esta teoría, junto con las que se ocupan de las interacciones electromagnéticas y débiles (unificadas en la teoría electrodébil) se combinan en el Modelo Estándar. El Modelo Estándar se construye en términos de un lagrangiano de campos cuantizados que describen grados fundamentales de libertad, quarks y leptones, y bosones que actúan como portadores de las interacciones citadas. Una de las preguntas abiertas más fundamentales en QCD se basa en entender cómo las propiedades de los hadrones observadas son generadas por la dinámica de sus componentes internos. Para dar algo de luz a esta pregunta, los físicos usan diferentes enfoques teóricos desde diferentes perspectivas, como QCD perturbativa, teorías de campo efectivas, QCD en el retículo, etc. Un campo de investigación muy interesante que puede ayudar mucho en este sentido, es la exploración de la estructura tridimensional de los hadrones. El objetivo principal de este campo es hacer una imagen tridimensional de un hadrón investigando la distribución de partones, conocidos como quarks y gluones, dentro de él. De esta manera, se pueden investigar cuestiones como el papel de los quarks y los gluones en la generación del espín del nucleón o el momento angular partónico. Por otro lado, existe un gran interés en la estructura de hadrónica por parte de la comunidad experimental con importantes instalaciones como JLab, DESY, BNL, CERN o KEK. Además, el LHC puede ayudar mucho en este tema, especialmente para comprender el papel de los gluones dentro de los protones. Recientemente, el gobierno de los Estados Unidos ha dado luz verde para comenzar la construcción de un nuevo acelerador, el Electron-Ion collider (EIC). Parte de las predicciones dadas en esta tesis están orientadas a ser probadas en este nuevo acelerador. Un tipo muy interesante de observables que pueden proporcionar información sobre la estructura hadrónica son los que tienen una dependencia no nula del momento transverso. Este interés proviene de poco tiempo después del establecimiento de QCD de una teoría fundamental de las interacciones fuertes [1–5]. Un punto crucial para tratar con este tipo de procesos es obtener teoremas de factorización bien definidos y así resumar las contribuciones de logaritmos grandes para realizar análisis fenomenológicos. Se ha trabajado mucho en este sentido para establecer teoremas de factorización para procesos con momento transverso no nulo para procesos muy relevantes como la producción de Drell-Yan (colisión protón-protón que conduce a un par de leptones en el estado final) o dispersión profundamente inelástica (colisiones electrón-protón que conducen a un hadrón en el estado final) [6–17]. En líneas generales, una sección eficaz factorizada se escribe en términos de un factor hard que incluye toda la física de altas energías y dos objetos que incluyen información sobre la distribución de partones dentro de los hadrones en el proceso. Estos elementos se conocen como funciones de distribución de partones dependientes del momento transverso (TMDPDF por sus siglas en inglés)...Fac. de Ciencias FísicasTRUEunpu