Filters
Results 1 - 10 of 477
Results 1 - 10 of 477.
Search took: 0.032 seconds
Sort by: date | relevance |
AbstractAbstract
[en] Three major effects from the interaction of e+e/sup /minus// beams---disruption, beamstrahlung, and electron-positron pair creation---are reviewed. For the disruption effects we discuss the luminosity enhancement factor, the maximum and rms disruption angles, and the ''kink instability''. All the results are obtained from computer simulations. Scaling laws for the numerical results and theoretical explanations of the computer acquired phenomena are offered wherever possible. For the beamstrahlung effects we concentrate only on the final electron energy spectrum resulting from multiple photon radiation process, and the deflection angle associated with low energy particles. For the effects from electron-positron pair creation, both coherent and incoherent processes of beamstrahlung pair creation are discussed. In addition to the estimation on total number of such pairs, we also look into the energy spectrum and the deflection angle. 17 refs., 23 figs., 1 tab
Primary Subject
Source
Jan 1989; 47 p; Physics of particle accelerators summer school; Batavia, IL (USA); 20 Jul - 14 Aug 1987; CONF-8707208--3; Available from NTIS, PC A03/MF A01 - OSTI; 1 as DE89007541; Portions of this document are illegible in microfiche products.
Record Type
Report
Literature Type
Conference
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] Gravitational radiation from high energy particles in modern accelerators is reviewed. We point out that the most effective way for laboratory production and detection of gravitons is through resonant photon-graviton conversion in a strong external EM field. Specific example using crystal channels for the γ → g → γ process is given, where the physical parameters needed for such a test appears to be reasonable. As another application of this effect in astrophysics, we show that the coupling between the cosmic microwave background radiation (CMBR) and the primordial magnetic field can induce a frequency-independent fluctuation in the photon flux. Using the observed CMBR fluctuation, we derive a bound on the primordial field strength. The effect can also convert the relic gravitons into photons. For the string cosmology it gives a new bound on the Hubble parameter at the Big Bang
Primary Subject
Secondary Subject
Source
Sep 1994; 9 p; 1. international conference on phenomenology of unification from present to future; Rome (Italy); 23-26 Mar 1994; CONF-9403118--2; CONTRACT AC03-76SF00515; Also available from OSTI as DE95002784; NTIS; US Govt. Printing Office Dep
Record Type
Report
Literature Type
Conference
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] The physical nature of beamstrahlung during beam-beam interaction in linear colliders is reviewed. We first make the distinction between a dense beam and a dilute beam. We then review the characteristics of synchrotron radiation (SR) and bremsstrahlung, and argue that for a wide range of beam parameters beamstrahlung is SR in nature, even if the beam is dilute. Some issues concerning the specific conditions in beamstrahlung as SR are then discussed. Finally we suggest that in order to suppress beamstrahlung energy loss and to improve energy resolution, it is desirable to partition a bunch into a train of bunchlets, where the length of each bunchlet is shorter than the SR convergence length
Primary Subject
Source
Apr 1987; 10 p; Workshop on physics at future accelerators; La Thuile (Italy); 7-10 Jan 1987; CONF-870180--1-SUMM; Available from NTIS, PC A02/MF A01; 1 as DE87012837; Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted.
Record Type
Report
Literature Type
Conference
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] In this paper we study various cosmological solutions for a D3/D7 system directly from M-theory with fluxes and M2-branes. In M-theory, these solutions exist only if we incorporate higher derivative corrections from the curvatures as well as G-fluxes. We take these corrections into account and study a number of toy cosmologies, including one with a novel background for the D3/D7 system whose supergravity solution can be completely determined. Our new background preserves all the good properties of the original model and opens up avenues to investigate cosmological effects from wrapped branes and brane-antibrane annihilation, to name a few. We also discuss in some detail semilocal defects with higher global symmetries, for example exceptional ones, that occur in a slightly different regime of our D3/D7 model. We show that the D3/D7 system does have the required ingredients to realize these configurations as non-topological solitons of the theory. These constructions also allow us to give a physical meaning to the existence of certain underlying homogeneous quaternionic Kahler manifolds
Primary Subject
Secondary Subject
Source
25 Jan 2005; [vp.]; AC--02-76SF00515; Available from PURL: https://www.osti.gov/servlets/purl/839660-LXJeEx/native/
Record Type
Report
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] The two major effects from the interaction of e/sup /minus//e+ beams---beamstrahlung and disruption---are reviewed, with emphasis on flat beam collisions. For the disruption effects we discuss the luminosity enhancement factor, the maximum and rms disruption angles, and the ''kink instability''. All the results are obtained from computer simulations, and scaling laws based on these are deduced whenever possible. For the beamstrahlung effects, we concentrate only on the final electron energy spectrum and the deflection angle associated with low energy particles. In addition to the generic studies on the beam-beam effects, we also list the relevant beam-beam parameters obtained from simulations on two sample designs: the TLC and the ILC. As an addendum, the newly discovered phenomenon of coherent beamstrahlung pair creation, together with the incoherent process, are discussed. 18 refs., 15 figs., 1 tab
Primary Subject
Source
Dec 1988; 10 p; DPF summer study: Snowmass '88 on high energy physics in the 1990s; Snowmass, CO (USA); 27 Jun - 15 Jul 1988; CONF-8806243--31; Available from NTIS, PC A02/MF A01 - OSTI; 1 as DE89007542; Portions of this document are illegible in microfiche products.
Record Type
Report
Literature Type
Conference
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] The intense radiation, called beamstrahlung, during the collision of e+e- beams in a linear collider, is reviewed, with attention to the influence of beam-beam disruption on the beamstrahlung spectrum. We then discuss the various detector backgrounds induced by these hard beamstrahlung photons, as well as the Weiszacker-Williams photon, through various QED and QCD processes, namely the coherent and incoherent e+e- pair creation and the hadron production and minijet yields
Primary Subject
Source
Sep 1992; 6 p; 9. international workshop on photon-photon collisions; San Diego, CA (United States); 22-26 Mar 1992; CONF-9203159--8; CONTRACT AC03-76SF00515; OSTI as DE93001821; NTIS; INIS; US Govt. Printing Office Dep
Record Type
Report
Literature Type
Conference
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] The method of Baier and Katkov is applied to calculate the correction terms to the Sokolov-Ternov radiation formula due to the variation of the magnetic field strength along the trajectory of a radiating particle. We carry the calculation up to the second order in the power expansion of B tau/B, where tau is the formation time of radiation. The expression is then used to estimate the quantum beamstrahlung average energy loss from e+e- bunches with gaussian distribution in bunch currents. We show that the effect of the field variation is to reduce the average energy loss from previous calculations based on the Sokolov-Ternov formula or its equivalent. Due to the limitation of our method, only an upper bound of the reduction is obtained. 18 refs
Primary Subject
Secondary Subject
Source
Aug 1987; 11 p; Workshop on new developments in particle acceleration techniques; Orsay (France); 29 Jun - 4 Jul 1987; CONF-8706147--10; Available from NTIS, PC A02/MF A01; 1 as DE88000704; Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted.
Record Type
Report
Literature Type
Conference
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] The Joint 28th ICFA (International Committee for Future Accelerators) Advanced Beam Dynamics and Advanced and Novel Accelerators Workshop on ''QUANTUM ASPECTS OF BEAM PHYSICS and Other Critical Issues of Beams in Physics and Astrophysics'', was held on January 7-11, 2003, in Hiroshima, Japan. This was the third in the QABP workshop series. The first QABP workshop was launched in January 1998, in Monterey, California, and the second was held in October 2000, in Capri, Italy. Over the past five years, this workshop series has passed its torch around the world, from the U.S. to Europe, and this time to Japan in Asia. Following the footsteps of the first two workshops, this one in Hiroshima was again a tremendous success. The frontier of beam research points to increasingly higher energy, greater brightness and lower emittance beams with ever-increasing particle species. These demands have triggered a rapidly growing number of beam phenomena that involve quantum effects. With the significant advancement of laser and accelerator technologies, there is also a growing interest in using high energy, high intensity particle and photon beams for laboratory astrophysics investigations, as well as the application of beam physics expertise to astrophysics studies. It has therefore become a tradition that this workshop series attracted a broad spectrum of experts from beam physics, astrophysics, cosmology, particle physics, condensed matter physics, nuclear physics, atomic physics, and laser science, to explore a common frontier where their individual expertise and interests overlapped
Primary Subject
Secondary Subject
Source
20 Apr 2004; [vp.]; 28. Joint ICFA Advanced Beam Dynamics and Advanced Nova Accelerator Workshops on Quantum Aspects of Beam Physics; Hiroshima (Japan); 7-11 Jan 2003; AC03-76SF00515; Available from PURL: https://www.osti.gov/servlets/purl/826882-iVcQa6/native/
Record Type
Report
Literature Type
Conference
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
No abstract available
Primary Subject
Source
7. International Symposium on Science of Superstrong Field Interactions; Shonan Village, Hayama (Japan); 13-15 Mar 2002; SLAC-REPRINT--2002-224; AC03-76SF00515; AIP Conf.Proc.634:178-186,2002
Record Type
Journal Article
Literature Type
Conference
Journal
AIP Conference Proceedings; ISSN 0094-243X; ; (Jan2002issue); [10 p.]
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] The idea of composite models of leptons and quarks is introduced with emphasis on the class of models that treats weak bosons also as composite particles. The mass scale of the underlying confining dynamics, the Quantum Haplodynamics (QHD), of the composite particles is argued to be much larger than the masses of the weak bosons. This unique feature of QHD is to be distinguished from Quantum Chromodynamics (QCD) in which the mass scale is comparable to the masses of low-lying hadrons. The statistical mechanical bulk quantities in field theories at finite temperature are discussed. A formulation is established where the weakly interacted system is treated as an ideal gas of quasiparticles. The thermodynamic bulk quantities such as entropy density and average charge density can then be expressed in a simple and elegant way. A specific example on (phi+ phi)2 theory under spontaneous symmetry breaking is given in detail. The correctness of this treatment is then checked by showing that the non-relativistic limit of the formulation is identical to the theory of superfluid helium
Primary Subject
Source
1984; 163 p; University Microfilms Order No. 84-11,850; Thesis (Ph. D.).
Record Type
Report
Literature Type
Thesis/Dissertation
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
1 | 2 | 3 | Next |