Biblioteca Digital

Several important and unique experimental high-energy physics programmes at a variety of facilities are coming to an end, including those at HERA, the B-factories and the Tevatron. The wealth of physics data from these experiments is the result of a significant financial and human effort, and yet until recently no coherent strategy existed for data preservation and re-use. To address this issue, an inter-experimental study group on data preservation and long-term analysis in high-energy physics was convened at the end of 2008, publishing an interim report in 2009. The membership of the study group has since expanded, including the addition of the LHC experiments, and a full status report has now been released. This report greatly expands on the ideas contained in the original publication and provides a more solid set of recommendations, not only concerning data preservation and its implementation in high-energy physics, but also the future direction and organisational model of the study group. The main messages of the status report were presented for the first time at the 2012 International Conference on Computing in High Energy and Nuclear Physics and are summarised in these proceedings.; Comment: Proceedings of plenary talk given at the 2012 International Conference on Computing in High Energy and Nuclear Physics (CHEP 2012). 8 pages...

The CERN-Latin-American School of High-Energy Physics is intended to give young physicists an introduction to the theoretical aspects of recent advances in elementary particle physics. These proceedings contain lectures on quantum field theory, quantum chromodynamics, physics beyond the Standard Model, neutrino physics, flavour physics and CP violation, particle cosmology, high-energy astro-particle physics, and heavy-ion physics, as well as trigger and data acquisition, and commissioning and early physics analysis of the ATLAS and CMS experiments. Also included are write-ups of short review projects performed by the student discussions groups.; Comment: 10 lectures, 560 pages, published as CERN Yellow Report http://cdsweb.cern.ch/record/1119305

One of the main challenges in Heavy Energy Physics is to make fast analysis of high amount of experimental and simulated data. At LHC-CERN one p-p event is approximate 1 Mb in size. The time taken to analyze the data and obtain fast results depends on high computational power. The main advantage of using GPU(Graphic Processor Unit) programming over traditional CPU one is that graphical cards bring a lot of computing power at a very low price. Today a huge number of application(scientific, financial etc) began to be ported or developed for GPU, including Monte Carlo tools or data analysis tools for High Energy Physics. In this paper, we'll present current status and trends in HEP using GPU.

There exists an enormous interest for the study of very high energy domain in particle physics, both theoretically and experimentally, in the aim to construct a general theory of the fundamental constituents of matter and of their interactions. Until now, semiconductor detectors have widely been used in modern high energy physics experiments. They are elements of the high resolution vertex and tracking system, as well as of calorimeters. The main motivation of this work is to discuss how to prepare some possible detectors - only silicon option being considered, for the new era of HEP challenges because the bulk displacement damage in the detector, consequence of irradiation, produces effects at the device level that limit their long time utilisation, increasing the leakage current and the depletion voltage, eventually up to breakdown, and thus affecting the lifetime of detector systems. In this paper, physical phenomena that conduce to the degradation of the detector are discussed and effects are analysed at the device level (leakage current and effective carrier concentration) in the radiation environments expected in the next generation of hadron colliders after LHC, at the next lepton and gamma-gamma colliders, as well as in astroparticle experiments...

The inward bound path of discovery unravelling the mysteries of matter and the forces that hold it together has culminated at the end of the twentieth century in a theory of the Fundamental Forces of Nature based on Nonabelian Gauge Fields, called the Standard Model of High Energy Physics. In this article we trace the historical development of the ideas and the experimental discoveries on which this theory is based. We also mark significant Indian contributions wherever possible. Finally we have a glimpse at future developments. An Appendix on more Indian contributions is added at the end.; Comment: 15 pages. Invited talk presented at the XIV DAE Symposium on High Energy Physics, Univ. of Hyderabad, Dec. 2000

This whitepaper summarizes the status, plans, and challenges in the area of integrated circuit design in the United States for future High Energy Physics (HEP) experiments. It has been submitted to CPAD (Coordinating Panel for Advanced Detectors) and the HEP Community Summer Study 2013(Snowmass on the Mississippi) held in Minnesota July 29 to August 6, 2013. A workshop titled: US Workshop on IC Design for High Energy Physics, HEPIC2013 was held May 30 to June 1, 2013 at Lawrence Berkeley National Laboratory (LBNL). A draft of the whitepaper was distributed to the attendees before the workshop, the content was discussed at the meeting, and this document is the resulting final product. The scope of the whitepaper includes the following topics: Needs for IC technologies to enable future experiments in the three HEP frontiers Energy, Cosmic and Intensity Frontiers; Challenges in the different technology and circuit design areas and the related R&D needs; Motivation for using different fabrication technologies; Outlook of future technologies including 2.5D and 3D; Survey of ICs used in current experiments and ICs targeted for approved or proposed experiments; IC design at US institutes and recommendations for collaboration in the future.

Besides using the laser beam, it is very tempting to directly testify the Bell inequality at high energy experiments where the spin correlation is exactly what the original Bell inequality investigates. In this work, we follow the proposal raised in literature and use the successive decays $J/\psi\to\gamma\eta_c\to \Lambda\bar\Lambda\to p\pi^-\bar p\pi^+$ to testify the Bell inequality. Our goal is twofold, namely, we first make a Monte-Carlo simulation of the processes based on the quantum field theory (QFT). Since the underlying theory is QFT, it implies that we pre-admit the validity of quantum picture. Even though the QFT is true, we need to find how big the database should be, so that we can clearly show deviations of the correlation from the Bell inequality determined by the local hidden variable theory. There have been some critiques on the proposed method, so in the second part, we suggest some improvements which may help to remedy the ambiguities indicated by the critiques. It may be realized at an updated facility of high energy physics, such as BES III.; Comment: 16 pages, 5 figures

Non-relativistic physics is often associated with atomic physics and low-energy phenomena of the strong interactions between nuclei and quarks. In this review we cover three topics in contemporary high-energy physics at or close to the TeV scale, where non-relativistic dynamics plays an important if not defining role. We first discuss in detail the third-order corrections to top-quark pair production in electron-positron collisions in the threshold region, which plays a major role at a future high-energy e+ e- collider. Threshold effects are also relevant in the production of heavy particles in hadronic collisions, where in addition to the Coulomb force soft gluon radiation contributes to enhanced quantum corrections. We review the joint resummation of non-relativistic and soft gluon effects for pair production of top quarks and supersymmetric particles to next-to-next-to-leading logarithmic accuracy. The third topic deals with pair annihilation of dark matter particles within the framework of the Minimal Supersymmetric Standard Model. Here the electroweak Yukawa force generated by the exchange of gauge and Higgs bosons can cause large "Sommerfeld" enhancements of the annihilation cross section in some parameter regions.; Comment: 36 pages...

World-wide collaboration in high-energy physics (HEP) is a tradition which dates back several decades, with scientific publications mostly coauthored by scientists from different countries. This coauthorship phenomenon makes it difficult to identify precisely the ``share'' of each country in HEP scientific production. One year's worth of HEP scientific articles published in peer-reviewed journals is analysed and their authors are uniquely assigned to countries. This method allows the first correct estimation on a ``pro rata'' basis of the share of HEP scientific publishing among several countries and institutions. The results provide an interesting insight into the geographical collaborative patterns of the HEP community. The HEP publishing landscape is further analysed to provide information on the journals favoured by the HEP community and on the geographical variation of their author bases. These results provide quantitative input to the ongoing debate on the possible transition of HEP publishing to an Open Access model.; Comment: For a better on-screen viewing experience this paper can also be obtained at: http://doc.cern.ch/archive/electronic/cern/preprints/open/open-2006-065.pdf

The traditional realm of astronomy is the observation and study of the largest objects in the Universe, while the traditional domain of high-energy physics is the study of the smallest things in nature. But these two sciences concerned with opposite ends of the size spectrum are, in Muir's words, bound fast by a thousand invisible cords that cannot be broken. In this essay I propose that collaborations of astronomers and high-energy physicists on common problems are beneficial for both fields, and that both astronomy and high-energy physics can advance by this close and still growing relationship. Dark matter and dark energy are two of the binding cords I will use to illustrate how collaborations of astronomers and high-energy physicists on large astronomical projects can be good for astronomy, and how discoveries in astronomy can guide high-energy physicists in their quest for understanding nature on the smallest scales. Of course, the fields have some different intellectual and collaborative traditions, neither of which is ideal. The cultures of the different fields cannot be judged to be right or wrong; they either work or they don't. When astronomers and high-energy physicists work together, the binding cords can either encourage or choke creativity. The challenge facing the astronomy and high-energy physics communities is to adopt the best traditions of both fields. It is up to us to choose wisely.; Comment: Why "Fundamentalist" Physics Is Good for Astronomy (in response to the paper of Simon White...

These lectures concern two topics that are becoming increasingly important in the analysis of High Energy Physics (HEP) data: Bayesian statistics and multivariate methods. In the Bayesian approach we extend the interpretation of probability to cover not only the frequency of repeatable outcomes but also to include a degree of belief. In this way we are able to associate probability with a hypothesis and thus to answer directly questions that cannot be addressed easily with traditional frequentist methods. In multivariate analysis we try to exploit as much information as possible from the characteristics that we measure for each event to distinguish between event types. In particular we will look at a method that has gained popularity in HEP in recent years: the boosted decision tree (BDT).; Comment: 22 pages, Lectures given at the 2009 European School of High-Energy Physics, Bautzen, Germany, 14-27 Jun 2009

In this Snowmass White Paper, we discuss physics opportunities involving heavy quarkonia at the intensity and energy frontiers of high energy physics. We focus primarily on two specific aspects of quarkonium physics for which significant advances can be expected from experiments at both frontiers. The first aspect is the spectroscopy of charmonium and bottomonium states above the open-heavy-flavor thresholds. Experiments at e^+ e^- colliders and at hadron colliders have discovered many new, unexpected quarkonium states in the last 10 years. Many of these states are surprisingly narrow, and some have electric charge. The observations of these charged quarkonium states are the first definitive discoveries of manifestly exotic hadrons. These results challenge our understanding of the QCD spectrum. The second aspect is the production of heavy quarkonium states with large transverse momentum. Experiments at the LHC are measuring quarkonium production with high statistics at unprecedented values of p_T. Recent theoretical developments may provide a rigorous theoretical framework for inclusive production of quarkonia at large p_T. Experiments at the energy frontier will provide definitive tests of this framework. Experiments at the intensity frontier also provide an opportunity to understand the exclusive production of quarkonium states.; Comment: 43 pages...

The Asia-Europe-Pacific School of High-Energy Physics is intended to give young physicists an introduction to the theoretical aspects of recent advances in elementary particle physics. These proceedings contain lectures on quantum field theory, quantum chromodynamics, flavour physics and CP-violation, physics beyond the Standard Model, neutrino physics, particle cosmology, heavy-ion physics, as well as a presentation of recent results from the Large Hadron Collider (LHC), practical statistics for particle physicists and a short introduction to the principles of particle physics instrumentation.; Comment: 8 lectures, 285 pages, published as CERN Yellow Report https://cds.cern.ch/record/1443909

I summarize our self-contained determinations of the lowest order hadronic contributions to the anomalous magnetic moments a_{\mu,\tau} of the muon and tau leptons, the running QED coupling \alpha(M_Z) and the muonium hyperfine splitting \nu. Using as a revised estimate of the light-by light scattering: a_\mu(LL)=85(18) 10^{-11}, we deduce: a_\mu^{SM} = 116 591 861(78) 10^{-11}, a_\tau^{SM} = 117 759(7) 10^{-8}, giving: a_\mu^{SM}-a_\mu^{exp}=162(170) 10^{-11}. We also obtain: \alpha^{-1}(M_Z)=128.926(25) and the Fermi energy splitting: \nu_F^{SM}=4 459 031 783(229) {Hz}. Lower bounds on some eventual new physics are given, while \nu_F^{SM} leads e.g. to m_\mu/m_e=206.768 276(11) in remarkable agreement with the data.; Comment: Latex 2e, 11 pages, 4 Tables, 1 eps.figure. Talk presented at the 1st High-Energy Physics Madagascar International Conference Series (HEP-MAD'01) 27th sept-5th oct. 2001, Antananarivo

In TeV-scale gravity, scattering of particles with center-of-mass energy of the order of a few TeV can lead to the creation of nonperturbative, extended, higher-dimensional gravitational objects: Branes. Neutral or charged, spinning or spinless, Einsteinian or supersymmetric, low-energy branes could dramatically change our picture of high-energy physics. Will we create branes in future particle colliders, observe them from ultra high energy cosmic rays, and discover them to be dark matter?; Comment: 8 pages, 2 figures. Essay submitted on Mar 26, 2002 to the Gravity Research Foundation. Awarded the third prize in the 2002 GRF competition

High energy physics data is a long term investment and contains the potential for physics results beyond the lifetime of a collaboration. Many existing experiments are concluding their physics programs, and looking at ways to preserve their data heritage. Preservation of high-energy physics data and data analysis structures is a challenge, and past experience has shown it can be difficult if adequate planning and resources are not provided. A study group has been formed to provide guidelines for such data preservation efforts in the future. Key areas to be investigated were identified at a workshop at DESY in January 2009, to be followed by a workshop at SLAC in May 2009. More information can be found at http://dphep.org; Comment: To appear in the proceedings of 44th Rencontres de Moriond on QCD and High Energy Interactions, La Thuile, Valle d'Aosta, Italy, 14-21 Mar 2009. 4 pages, 2 figures + 1 photo, 1 style file

Evolutionary Computation is a branch of computer science with which, traditionally, High Energy Physics has fewer connections. Its methods were investigated in this field, mainly for data analysis tasks. These methods and studies are, however, less known in the high energy physics community and this motivated us to prepare this lecture. The lecture presents a general overview of the main types of algorithms based on Evolutionary Computation, as well as a review of their applications in High Energy Physics.; Comment: Lecture presented at 2006 Inverted CERN School of Computing; to be published in the school proceedings (CERN Yellow Report)

These are lecture notes of an introduction to quantum integrability given at the Tenth Modave Summer School in Mathematical Physics, 2014, aimed at PhD candidates and junior researchers in theoretical physics. We introduce spin chains and discuss the coordinate Bethe ansatz (CBA) for a representative example: the Heisenberg XXZ model. The focus lies on the structure of the CBA and on its main results, deferring a detailed treatment of the CBA for the general $M$-particle sector of the XXZ model to an appendix. Subsequently the transfer-matrix method is discussed for the six-vertex model, uncovering a relation between that model and the XXZ spin chain. Equipped with this background the quantum inverse-scattering method (QISM) and algebraic Bethe ansatz (ABA) are treated. We emphasize the use of graphical notation for algebraic quantities as well as computations. Finally we turn to quantum integrability in the context of theoretical high-energy physics. We discuss factorized scattering in two-dimensional QFT, and conclude with a qualitative introduction to one current research topic relating quantum integrability to theoretical high-energy physics: the Bethe/gauge correspondence.; Comment: 74 pages, 10 figures, 3 tables; v2: minor corrections

Data from high-energy physics experiments are collected with significant financial and human effort and are mostly unique. However, until recently no coherent strategy existed for data preservation and re-use, and many important and complex data sets have simply been lost. While the current focus is on the LHC at CERN, in the current period several important and unique experimental programs at other facilities are coming to an end, including those at HERA, b-factories and the Tevatron. To address this issue, an inter-experimental study group on HEP data preservation and long-term analysis (DPHEP) was convened at the end of 2008. The group now aims to publish a full and detailed review of the present status of data preservation in high energy physics. This contribution summarises the results of the DPHEP study group, describing the challenges of data preservation in high energy physics and the group's first conclusions and recommendations. The physics motivation for data preservation, generic computing and preservation models, technological expectations and governance aspects at local and international levels are examined.; Comment: 8 pages, 6 figures, proceedings of ACAT 2011 poster

An inter-experimental study group, DPHEP, was formed in 2009 to systematically investigate the technical and organisational aspects of data preservation and long-term analysis in high-energy physics, a subject which had hitherto lacked clarity in the field. The study group includes representation from all major high-energy physics collider-based experiments and laboratories, as well as computing centres and funding agencies. A major report was released in May 2012, greatly expanding on the ideas contained in a preliminary publication three years earlier, and providing a more solid set of recommendations, not only concerning data preservation and its implementation in high-energy physics, but also the future direction and organisational model of the study group. A brief description of the DPHEP Study Group and some of the key messages from the major report are presented.; Comment: 6 pages, 2 figures; proceedings of talk given at ICHEP 2012, Melbourne, July 2012