High Energy Physics Research Research Articles

Physics of shower simulation at LHC, at the example of geant4

The LHC experiments will explore new frontiers of particle physics, and open new ways for experimental research in high energy and nuclear physics. To maximize the physics potential of LHC, we need simulation of lepton and hadron interactions and cross-sections in the collider, shielding, and detectors. We need to be able to predict both the detector responses, and the radiation environments in the context of the planned machine operation scenarios. This can be realized through detailed simulation of the paths of particles traversing the materials of the experimental set-up. The experimental conditions posed by the LHC, which will be operating at higher energy, luminosity and precision than the present colliders, are very demanding. Triggered by this challenge, the physics modeling of interactions of leptons and hadrons with nuclei, and the associated final state generators and cross-section calculations, have seen significant advances both on the theoretical and technical level during the last few years. We will discuss the methods of physics in particle transport, and review recent advances at the example of the GEANT4 simulation tool-kit, that was built for the LHC experiments. The focus will be on soft hadronic and nuclear physics.

Tom Ypsilantis: His crucial contribution to High Energy Physics Research in Greece

Tom Ypsilantis: His crucial contribution to High Energy Physics Research in Greece

Development of hybrid photodetectors using single-crystal III–V photocathodes

Improved performance photodetectors are required for a variety of applications in Biomedical, Astronomy and High-Energy Physics research. The combination of high Quantum efficiencies, III–V photocathodes and Avalanche PhotoDiodes (APDs) can provide enhancements applicable to these research areas. This is particularly true in the photon counting regime. Preliminary development of a Winston-cone-based Hybrid device (ReFerence) and an APD-based imaging Hybrid Photomultiplier Tube are presented. These devices take advantage of the high-performance cathodes and mechanically robust structures used in state of the art night vision imagining systems. Theoretical and observed performance are described.

A Proposal for Rescaling Units

Several physical quantities are thought of as having “obvious” upper or lower bounds in their magnitudes. Temperature, for example, cannot go below absolute zero, the magnitude of any velocity is at most c, the speed of light, and time cannot go back past the Big Bang. In life outside the laboratory, we never get very close to any of these bounds, so they pose no problem. However, researchers in cryogenics, cosmology, and high-energy physics work at values that are perceived to be close to these limits. We read of temperatures one one-hundredth of a degree above absolute zero (that is, 0.01 K); of velocities at 99.95% of the speed of light; and of the state of the cosmos at 10−8 seconds after the Big Bang. In these cases, the standard system of units is inconvenient. Getting three orders of magnitude closer to 0 K, or to the time of the Big Bang, or to the speed of light, should not be obscured by the appearance that the change is merely an infinitesimal improvement.A change of units that maps zero to minus infinity and, in the case of velocity, maps c to plus infinity makes it easier to appreciate improvements that get closer to these bounds by orders of magnitude. This principle has been in use for a long time by engineers who measure changes in intensity in decibels (dB), where an increase or decrease by n orders of magnitude is a change of +10n dB or −10n dB, respectively.For physical quantities like time and temperature, the new units may simply be taken as the common logarithms of the old units. Using T to represent the new unit of temperature, we set 1 K = 0 T with (10 n ) K = n T for negative as well as positive values for n. Thus, 0.01 K = −2 T. More generally, x K = (log10 x) T, for any positive real number x. A similar approach applies to time since the Big Bang, where “x seconds after the Big Bang” becomes (log10 x) U, where U is our new, logarithmic measure of time.For velocity magnitudes v, with 0 ≤ v ≤ c, we can rescale to V = tan(πv/2c), with 0 ≤ V ≤ + ∞. At υ=1/2c,, this gives V=tan(π/4)=1..For nanotechnology researchers, the lower limit of zero for weight, length, and so forth can be moved to minus infinity by the same logarithmic technique used above for time and temperature. Names and symbols for these new units should be recommended by appropriate standards committees for each of the research areas involved.© 2001 American Institute of Physics.

Richard Lee Childers

Richard Lee Childers, Distinguished Professor Emeritus at the University of South Carolina (USC) who had a lifelong interest in the history of physics and was an avid collector of antique physics apparatus, died in Columbia, South Carolina, of lung cancer on 19 February 2000.Born in Birmingham, Alabama, on 10 December 1930, Richard obtained three degrees in physics: a BA from Presbyterian College in 1953, an MS from the University of Tennessee in 1956, and a PhD from Tennessee in 1962. In 1963, he became an assistant professor of physics at USC and then an associate professor in 1966. He served from 1968 to 1970 as the director of the USC honors program before the present Honors College was established (in 1977).From the mid-1960s until the early 1970s, Richard collaborated with other members of the USC intermediate energy group, first on the Cosmotron at Brookhaven National Laboratory. Because of a lack of funds, however, the group had to bootleg time on the Cosmotron, borrowing the University of Rochester’s spectrometer—which was installed on the beam line at the Cosmotron—and its ancillary electronic equipment when beam time was assigned. The group later collaborated on the cyclotron at NASA’s Space Radiation Effects Laboratory in Newport News, Virginia. One time the group members were told they could run on the cyclotron if they went there immediately. So they loaded their equipment onto a colleague’s plane, flew up to the cyclotron in Virginia, and were running within four hours.A permanent faculty member at USC, Richard conducted research as a “suitcase physicist,” traveling to laboratories for short intervals when beam times were available for specific experiments. From 1972 to 1978, he worked at USC on problems connected with acoustics. His research in high-energy physics took him to Europe in the late 1970s, where he worked with Colgate W. Darden III on the Argus Detector at the German Electron Synchrotron (DESY). This effort represented the first high-energy experimental research performed by the university’s department of physics and astronomy. In 1982, Richard was promoted to professor. He continued his work on Argus until 1986.In 1988, Richard worked on the Čerenkov detector at Fermilab. However, he devoted most of his available time during the mid- to late 1980s to writing, mostly as a coauthor. He published more than 150 research articles, but is perhaps best known for his coauthorship with one of us (E.R.J) of Contemporary College Physics (McGraw-Hill, 2001), a textbook that has been widely used in noncalculus introductory physics. Many of the photographs in the text were taken by Richard, and remain as a reminder of his interest in optics and his skill as a photographer.Richard finished his research at Fermilab in 1992. In 1993, USC honors students named him outstanding professor of science. He retired from USC in 1996, but continued to work there part time until his death.Richard had a special regard for physics demonstrations, which was heightened by his interest in magic and an understanding of the showmanship involved. He once developed a bed of nails at a 1972 workshop on physics demonstrations. That workshop, sponsored by the National Science Foundation, was held at the US Naval Academy in Annapolis, Maryland, by Richard B. “Dick” Minnix and Rae Carpenter Jr, who were members of the physics faculty at the Virginia Military Institute. Anyone who has tried lying on a bed of nails knows the great sense of relief, on lowering himself or herself onto the bed, that physics really works! A member of ring 105 (a local branch) of the International Brotherhood of Magicians in Columbia, South Carolina, Richard carried his showmanship into the classroom.Throughout his career, Richard actively promoted physics education in the high schools. Early on, he arranged for high-school students to visit the university, where they were given tours of the research laboratories and a demonstration lecture on physics. His efforts culminated with his organization of the Midway Physics Day at the South Carolina State Fair following his retirement. His calm, commonsense perspective on departmental matters will be missed by his colleagues. Richard Lee Childers PPT|High resolution© 2001 American Institute of Physics.

高エネルギー物理研究における超伝導磁石技術

Superconducting magnet technologies have been developed as the necessary technologies for high-energy physics research. One of the applications is for the high-energy accelerators, which have to be as large as possible. On the other hand, superconducting magnets have been required for particle detectors in order to obtain higher magnetic field and save electric power. Three superconducting accelerators are being operated and a larger machine that uses NbTi coil cooled by He II, the LHC, is under construction. Many particle detector magnets have been developed and constructed to detect and analyze generated particles. Recent key technologies for the particle detector magnets are aluminumstabilized superconductors and an inner winding method. Very thin detector magnets have been developed and successfully used. In this paper, superconducting magnet technologies for accelerators and particle detectors are described.

The PEREGRINETM program: using physics and computer simulation to improve radiation therapy for cancer

When using radiation to treat cancer, doctors rely on physics and computer technology to predict where the radiation dose will be deposited in the patient. The accuracy of computerized treatment planning plays a critical role in the ultimate success or failure of the radiation treatment. Inaccurate dose calculations can result in either insufficient radiation for cure, or excessive radiation to nearby healthy tissue, which can reduce the patient's quality of life. This paper describes how advanced physics, computer, and engineering techniques originally developed for nuclear weapons and high-energy physics research are being used to predict radiation dose in cancer patients. Results for radiation therapy planning, achieved in the Lawrence Livermore National Laboratory (LLNL) program show that these tools can give doctors new insights into their patients' treatments by providing substantially more accurate dose distributions than have been available in the past. It is believed that greater accuracy in radiation therapy treatment planning will save lives by improving doctors' ability to target radiation to the tumour and reduce suffering by reducing the incidence of radiation-induced complications.

Out of particles: Impact of CERN, DESY and SLAC research to fields other than physics

Abstract This paper presents the results of an exploratory bibliometric study aiming at an analysis of basic high energy physics (HEP) research impact on fields other than physics, and particularly on application-oriented R&D. After a general discussion of an extensive citation analysis of basic research publications from three HEP institutes—CERN, DESY, and SLAC—the paper focuses on the ‘knowledge flow’ from physics to non-physics, and more specifically the flow from basic physics research to the ‘applied world’. At this level, we report journal- as well as research field characteristics, and we identify the most frequently citing R&D groups. We conclude that DESY is most cited by the ‘applied world’, followed by SLAC and CERN. If the number of journals that institutes have in common—whether based on the source or the citing publication—is taken as an indicator of the resemblance of their research interests, we found that CERN and SLAC have the closest resemblance, followed by SLAC and DESY, with CERN a...

The way it was

A remarkable conference was held in Dubna, 60 miles north of Moscow on the River Volga. At Dubna, founded in the late 1940s as a center of research in nuclear and high-energy physics, over 130 papers were presented on the history of the Soviet nuclear project from 1943 to 1954. Some presentations were made by foreign guests, but the overwhelming majority of papers were presented by Russian historians and participants in the nuclear project providing a great deal of new information. The conference initiative came from a group of historians and scientists who had organized a regular seminar on the history of the Soviet project the previous two years. The Russian Academy of Sciences, the Kurchatov Institute, and the Ministry of Atomic Energy agreed to provide formal sponsorship. Many excellent papers were presented. The conference organizers hope to publish the proceedings in English as well as in Russian although that plan appears to be in doubt for lack of funds. Perhaps a foundation will provide the necessary support, so that historians will have access to this important historical material. One panel included three papers on the development of Soviet thermonuclear weapons. Two papers provide a new level of insight intomore » the Soviet effort to build thermonuclear bombs.« less

Using STEP in a high energy physics research environment

We present the utility program GESTEP where principles of STEP were applied to detector models used by the GEANT physics simulation package. It reads GEANT detector models and converts them to object instances in a class library in order to be easily accessible by other applications.

Beijing Synchrotron Radiation Facility

The storage ring for the Beijing Synchrotron Radiation Facility (BSRF) is the 1.6–2.8 GeV Beijing Electron-Positron Collider, which was constructed for China’s first project on high-energy physics research. The storage ring was designed to be operating either in the colliding mode or in the dedicated synchrotron-radiation mode. The project was approved by the Chinese government at the end of 1983, and was completed in 1989. The Beijing Synchrotron Radiation Laboratory was founded in July of 1985, and the construction of the first beam line was completed in 1989. The first phase construction of BSRF was finished in 1991; three beam ports, seven beam lines, and nine experimental stations were constructed. Since 1991, BSRF has been opened to users from all over the country. The description of the beam lines and experimental stations and present research activities is given in this paper. The second phase construction of BSRF as well as the plan of constructing a third-generation new synchrotron-radiation source, the Beijing Light Source, adjacent to BSRF, are described.

Characteristics of a high energy μ+μ− collider based on electro-production of muons

We analyze the design of a high energy μ + μ − collider based on electro-production of muons. We derive an expression for the luminosity in terms of analytic formulae for the electron-to-muon conversion efficiency and the electron beam power on the production target. On the basis of studies of self-consistent sets of collider parameters under “realistic” (“optimistic”) assumptions about available technology with beam cooling, we find the luminosity limited to 10 27 cm −2 s −1 (10 28 cm −2 s −1). We also identify major technological innovations that will be required before μ +μ − colliders can offer sufficient luminosity (10 30 cm −2 s −1) for high energy physics research.

The World-Wide Web

Publisher Summary This chapter discusses the history and growth of World Wide Web (W3). The World-Wide Web was developed to be a pool of human knowledge, which would allow collaborators in remote sites to share their ideas and all aspects of a common project. Physicists and engineers at CERN, the European Particle Physics Laboratory in Geneva, Switzerland, collaborate with many other institutes to build the software and hardware for high-energy physics research. The idea of the Web was prompted by positive experience of a small “home-brew” personal hypertext system used for keeping track of personal information on a distributed project. The Web was designed so that if it was used independently for two projects, and later relationships were found between the projects, then no major or centralized changes would have to be made, but the information could smoothly reshape to represent the new state of knowledge. This property of scaling has allowed the Web to expand rapidly from its origins at CERN across the Internet irrespective of boundaries of nations or disciplines.

American chambers

Following the discovery of the bubble chamber by Don Glaser, there was immediate recognition by many American high energy physics research groups of the great potential for improved experimentation using bubble chambers. This paper traces the American effort, attempting to include the significant steps (leaving out the Alvarez group's contribution) that lead to the dominance of the bubble chamber technique for high energy physics research for many years.

A high-speed analog neural processor

Targeted at high-energy physics research applications, our special-purpose analog neural processor can classify up to 70 dimensional vectors within 50 nanoseconds. The decision-making process of the implemented feedforward neural network enables this type of computation to tolerate weight discretization, synapse nonlinearity, noise, and other non-ideal effects. Although our prototype does not take advantage of advanced CMOS technology, and was fabricated using a 2.5-/spl mu/m CMOS process, it performs 6 billion multiplications per second, with only 2 W dissipation, and has as high as 1.5 Gbyte/s equivalent bandwidth. >

"High-Power Microwave" tubes: in the laboratory and on-line

The possibility of incapacitating the electronic circuits of hostile equipment with high-energy microwave pulses has created a demand for microwave tubes capable of very high peak pulsed powers. Experimentalists, primarily from the plasma physics community, have been working in this field, dubbed High-Power Microwave or HPM. Separately, research in high-energy physics requires electron-positron colliders with energies approaching 1 trillion electron-volts (1 terra-electron-volt, or TeV). Such accelerators must be powered by microwave sources that are very similar to some that are proposed for the HPM application. The paper points out that for these tubes to be used on-line in the manner intended, they must be designed and built to operate at a very high internal vacuum, which is not the case for many of the HPM laboratory projects. The development of a particular klystron at the Stanford Linear Accelerator Center is described in detail in order to illustrate the need for special facilities and strong quality control. Should the defense requirements for HPM survive the end of the cold war, an effort should be made to coordinate the tube development activities serving these two widely disparate applications.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

RareKdecays

This article reviews the current situation in the field of rare $K$ decays: the relevant phenomenology, the present experimental situation, and prospects for the near future. Study of rare $K$ decays can make a significant contribution in a number of different frontier areas of research in high-energy physics. In the area of $\mathrm{CP}$ violation, study of such rare decays as ${K}_{L}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{e}^{+}{e}^{\ensuremath{-}}$, ${K}_{L}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, ${K}_{L}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, and muon polarization in ${K}_{L}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ can provide important complementary information to what has been learned from the decay ${K}_{L}^{0}\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}$. Even though experiments with sufficient accuracy to make a meaningful study of $\mathrm{CP}$ violation are still a few years away, significant progress has been made in this general area during the last decade. A second major area of interest in the field of rare $K$ decays is the search for processes forbidden in the Standard Model, e.g., ${K}_{L}^{0}\ensuremath{\rightarrow}\ensuremath{\mu}e$ and ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\mu}}^{+}{e}^{\ensuremath{-}}$. Various extensions of the Standard Model predict that these processes will occur with branching fractions in the range of ${10}^{\ensuremath{-}10}$ to ${10}^{\ensuremath{-}15}$. Experiments of the last decade have pushed the limits into the ${10}^{\ensuremath{-}10}$ to ${10}^{\ensuremath{-}11}$ range, and further improvements in sensitivity of one to two orders of magnitude can be expected in the next few years. $K$ decays allow one also to study higher-order weak-interaction processes such as ${K}_{L}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, ${K}_{L}^{0}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}$, ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, which are forbidden to first order in the Standard Model. Because of strong suppression, these decay modes offer potential windows on new physics; in addition, they may offer the most reliable measurement of ${V}_{\mathrm{td}}$, one of the elements of the weak mixing matrix in the quark sector. The studies of the ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ channel have achieved data samples of close to 1000 events; the other two modes should be observed for the first time in the next few years. Finally, as a byproduct of these studies, one has been able to look simultaneously for new light particles into which the $K$ meson could decay. Limits obtained for various hypothetical particles are summarized.

Cooperation in High Energy Physics Research Between the United States and Japan

Cooperation in High Energy Physics Research Between the United States and Japan

Analysing The Economic Payoffs From Basic Research

Cost benefit approaches for evaluating the contribution of basic research investment have severe limitations and a number of undesirable consequences. We propose an alternative, information-theoretic, approach for identifying the economic benefits engendered by basic research. We emphasize the role of information linkages, the economic value of both findings and non-findings, and the consequences of disclosure incentives for realizing the economic benefits from basic research investments. We introduce the concepts of homotopic mappings and analogic links as relevant for differentiating among the prospective contributions of competing basic research projects, and we examine how the lumpiness or indivisibility of basic research investments may influence the conduct of basic research. The methodology and reasoning of our approach is illustrated by an examination of the case of basic research in high energy physics.

Scientific realism and experimental practice in High-Energy Physics

The issue of scientific realism is discussed in terms of the specific details of the practice of experimental meson and baryon spectroscopy in the field of High-Energy Physics (HEP), during the period from 1966 to 1970. The philosophical positions of I. Hacking, A. Fine, J. Leplin, and N. Rescher that concern scientific realism are presented in such a manner as to allow for the evaluation of their appropriateness in the description of this experimental research field. This philosophical analysis focuses on the empirical adequacy of these four philosophical models that purport to describe the process of acquiring knowledge of the physical world. In this specific case, an experiment performed by the HEP research group at the University of Notre Dame to study the scattering interaction $$\pi ^ + P \to P\pi ^ + \pi ^ + \pi ^ - \pi ^0 $$ at 18.5 GeV/c is discussed. The specific details of the research practices employed in this experiment are analyzed in light of the philosophical models presented herein. A summary of the relevant aspects of this successful description is presented.