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Status and performance of the CDF run 2 silicon detectors

Description: In 2001, an upgraded silicon detector system was installed in the CDF II experiment on the Tevatron at Fermilab. The complete system consists of three silicon micro-strip detectors: SVX II with five layers for precision tracking, Layer 00 with one beampipe-mounted layer for vertexing, and two Intermediate Silicon Layers located between SVX II and the main CDF II tracking chamber. Currently all detectors in the system are operating at or near design levels. The performance of the combined silicon system is excellent in the context of CDF tracking algorithms,and the first useful physics results from the innermost Layer 00 detector have been recently documented. Operational and monitoring efforts have also been strengthened to maintain silicon efficiency through the end of Run 2 at the Tevatron.
Date: December 2, 2004
Creator: Nielsen, Jason
Partner: UNT Libraries Government Documents Department

Grand initial value problem of high gain free electronlasers

Description: Initial value problem is one of the cornerstones in the framework of high gain FEL theory. It determines the startup of FEL interaction from initial signal or noise in either laser field or electron beam. Yet, this problem was solved only for the cases without emittance and betatron oscillations. I present the first solution to the initial value problem in a grand scale by expanding the startup theory into the full six-dimensional phase space, deriving both general solution valid for any beam distribution and specific solution for a Gaussian model. One of the major results of this letter is the discovery of excessively large noise power for SASE.
Date: December 1, 2000
Creator: Xie, Ming
Partner: UNT Libraries Government Documents Department

Terascale Beam-Beam Simulations for Tevatron, RHIC and LHC

Description: In this paper, we report on recent advances in terascale simulations of the beam-beam interaction in Tevatron, RHIC and LHC.Computational methods for self consistent calculation of beam-beam forces are reviewed. New method for solving the two-dimensional Poisson equation with open boundary conditions is proposed and tested. This new spectral-finite difference method is a factor of four faster than the widely used FFT based Green function method for beam-beam interaction on axis. We also present applications to the study of antiproton losses during the injection stage at Tevatron, to the study of multiple bunch coherent beam-beam modes at RHIC, and to the study of beam-beam driven emittance growth at LHC.
Date: May 16, 2005
Creator: Qiang, J.
Partner: UNT Libraries Government Documents Department

Introduction to heavy meson decays and CP asymmetries

Description: These lectures are intended to provide an introduction to heavy meson decays and CP violation. The first lecture contains a brief review of the standard model and how the CKM matrix and CP violation arise, mixing and CP violation in neutral meson systems, and explanation of the cleanliness of the sin 2{beta} measurement. The second lecture deals with the heavy quark limit, some applications of heavy quark symmetry and the operator product expansion for exclusive and inclusive semileptonic B decays. The third lecture concerns with theoretically clean CP violation measurements that may become possible in the future, and some developments toward a better understanding of nonleptonic B decays. The conclusions include a subjective best buy list for the near future.
Date: February 5, 2003
Creator: Ligeti, Zoltan
Partner: UNT Libraries Government Documents Department

Geometry, topology, and string theory

Description: A variety of scenarios are considered which shed light upon the uses and limitations of classical geometric and topological notions in string theory. The primary focus is on situations in which D-brane or string probes of a given classical space-time see the geometry quite differently than one might naively expect. In particular, situations in which extra dimensions, non-commutative geometries as well as other non-local structures emerge are explored in detail. Further, a preliminary exploration of such issues in Lorentzian space-times with non-trivial causal structures within string theory is initiated.
Date: July 10, 2003
Creator: Varadarajan, Uday
Partner: UNT Libraries Government Documents Department

Introduction to heavy meson decays and CP asymmetries

Description: These lectures are intended to provide an introduction to heavy meson decays and CP violation. The first lecture contains a brief review of the standard model and how the CKM matrix and CP violation arise, mixing and CP violation in neutral meson systems, and explanation of the cleanliness of the sin 2{beta} measurement. The second lecture deals with the heavy quark limit, some applications of heavy quark symmetry and the operator product expansion for exclusive and inclusive semileptonic B decays. The third lecture concerns with theoretically clean CP violation measurements that may become possible in the future, and some developments toward a better understanding of nonleptonic B decays. The conclusions include a subjective best buy list for the near future.
Date: February 5, 2003
Creator: Ligeti, Zoltan
Partner: UNT Libraries Government Documents Department

Dust around Type Ia supernovae

Description: An explanation is given of the low value of R lambda triple bond A lambda/E(B - V), the ratio of absolute to selective extinction deduced from Type Ia supernova observations. The idea involves scattering by dust clouds located in the circumstellar environment, or at the highest velocity shells of the supernova ejecta. The scattered light tends to reduce the effective R lambda in the optical, but has an opposite effect in the ultraviolet. The presence of circumstellar dust can be tested by ultraviolet to near infrared observations and by multi-epoch spectropolarimetry of SNe Ia.
Date: October 20, 2005
Creator: Wang, Lifan
Partner: UNT Libraries Government Documents Department

Einstein: His Impact on Accelerators; His Impact on theWorld

Description: The impact of the work of Albert Einstein on accelerator physics is described. Because of the limit of time, and also because the audience knows the details, the impact is described in broad strokes. Nevertheless, it is seen how his work has affected many different aspects of accelerator physics. In the second half of the talk, Albert Einstein's impact on the world will be discussed; namely his work on world peace (including his role as a pacifist, in the atomic bomb, and in arms control) and his efforts as a humanitarian (including his efforts on social justice, anti-racism, and civil rights).
Date: July 30, 2005
Creator: Sessler, A.
Partner: UNT Libraries Government Documents Department

Investigation of high-precision {Lambda} hypernuclear spectroscopy via the (e,e'K{sup +}) reaction

Description: The study of {Lambda} hypernuclear structure is very interesting in point of the understanding of the interaction between {Lambda} and nucleon ({Lambda}-N interaction) and its ”strange” structure itself due to the containment of a {Lambda} hyperon which has a strangeness as a new degree of freedom. In the several way to study the Lamda hypernuclei, the (e,e'K{sup +}) reaction spectroscopy is a powerful tool for the precise investigation of {Lamda} hypernuclear structure. The purpose of the preset thesis is the establishment of the experimental design with the efficient data analysis method for the (e,e'K{sup +}) hypernuclear spectroscopic experiment in the wide mass region (from A=7 to A=52). It is very challenging to perform the (e,e'K{sup +}) spectroscopic experiment with such a heavy target, because of the huge electron background due to the bremsstrahlung process. In the experiment, it is required to obtain the necessary hypernuclear yield, suppressing the background event ratio. We achieved these requirements by newly constructing the high resolution electron spectrometer (HES) and splitter magnet (SPL) dedicated to the (e,e'K{sup +}) spectroscopic experiment. The HES consists of two quadrupole magnets and a dipole magnets (Q-Q-D) with a momentum resolution of dp/p = 3x10^-4 at p = 0.84 GeV/c. It was used being vertically tilted by 6.5 degree so as to optimize signal to noise ratio and hypernuclear yield. The SPL is a dipole magnet. The experimental target was placed at the entrance of this magnet. The role of the SPL is to separate four kind of particles; scattered kaons, photons created by the bremsstrahlung, the post beam and scattered electrons. In addition, since the SPL is a part of the kaon and electron spectrometers. We designed the magnet shape carefully considering these points. The experiment was performed with 2.344 GeV/c electron beam from CEBAF at Jefferson Lab. The ...
Date: March 31, 2012
Creator: Kawama, Daisuke
Partner: UNT Libraries Government Documents Department

Diversity of Decline-Rate-Corrected Type 1a Supernova Rise times:One Mode or Two?

Description: B-band light-curve rise times for eight unusually well-observed nearby Type Ia supernova (SNe) are fitted by a newly developed template-building algorithm, using light-curve functions that are smooth, flexible, and free of potential bias from externally derived templates and other prior assumptions. From the available literature, photometric BVRI data collected over many months, including the earliest points, are reconciled, combined, and fitted to a unique time of explosion for each SN. On average, after they are corrected for light-curve decline rate, three SNe rise in 18.81 {+-} 0.36 days, while five SNe rise in 16.64 {+-} 0.21 days. If all eight SNe are sampled from a single parent population (a hypothesis not favored by statistical tests), the rms intrinsic scatter of the decline-rate-corrected SN rise time is 0.96{sub -0.25}{sup +0.52} days--a first measurement of this dispersion. The corresponding global mean rise time is 17.44 {+-} 0.39 days, where the uncertainty is dominated by intrinsic variance. This value is {approx}2 days shorter than two published averages that nominally are twice as precise, though also based on small samples. When comparing high-z to low-z SN luminosities for determining cosmological parameters, bias can be introduced by use of a light-curve template with an unrealistic rise time. If the period over which light curves are sampled depends on z in a manner typical of current search and measurement strategies, a two-day discrepancy in template rise time can bias the luminosity comparison by {approx}0.03 magnitudes.
Date: May 1, 2007
Creator: Strovink, Mark
Partner: UNT Libraries Government Documents Department

Frequency Map Studies for the ILC Damping Rings

Description: Designing a lattice with sufficient dynamic aperture for theILCDamping Rings is very challenging as the lattice needs to provide asmall equilibrium emittance and at the same time a large aperture for theinjected beam (including a large momentum acceptance). In addition,outside constraints have forced layout changes in the damping ring. Someof the layout changes had an impact on thedynamic aperture. In order tobetter understand the changes indynamic aperture, frequency maps arestudied. Those studies can help in identifying the reason for the changeddynamic apertureand in finding a good location for the betatron tunes anddetermining an upper limit for the chromaticities. A summary of recentstudies and suggestions for improving the dynamic aperture bychoosing adifferent tune are presented.
Date: June 20, 2007
Creator: Reichel, Ina
Partner: UNT Libraries Government Documents Department

E-Cloud Build-up in Grooved Chambers

Description: We simulate electron cloud build-up in a grooved vacuumchamber including the effect of space charge from the electrons. Weidentify conditions for e-cloud suppression and make contact withprevious estimates of an effective secondary electron yield for groovedsurfaces.
Date: May 1, 2007
Creator: Venturini, Marco
Partner: UNT Libraries Government Documents Department

To Crack or Not to Crack: Strain in High TemperatureSuperconductors

Description: Round wire Bi 2212 is emerging as a viable successor ofNb3Sn in High Energy Physics and Nuclear Magnetic Resonance, to generatemagnetic fields that surpass the intrinsic limitations of Nb3Sn. Ratherbold claims are made on achievable magnetic fields in applications usingBi 2212, due to the materials' estimated critical magnetic field of 100 Tor higher. High transport currents in high magnetic fields, however, leadto large stress on, and resulting large strain in the superconductor. Theeffect of strain on the critical properties of Bi-2212 is far fromunderstood, and strain is, as with Nb3Sn, often treated as a secondaryparameter in the design of superconducting magnets. Reversibility of thestrain induced change of the critical surface of Nb3Sn, points to anelectronic origin of the observed strain dependence. Record breaking highfield magnets are enabled by virtue of such reversible behavior. Straineffects on the critical surface of Bi-2212, in contrast, are mainlyirreversible and suggest a non-electronic origin of the observed straindependence, which appears to be dominated by the formation of cracks inthe superconductor volumes. A review is presented of available results onthe effects of strain on the critical surface of Bi-2212, Bi-2223 andYBCO. It is shown how a generic behavior emerges for the (axial) straindependence of the critical current density, and how the irreversiblereduction of the critical current density is dominated by strain inducedcrack formation in the superconductor. From this generic model it becomesclear that magnets using high temperature superconductors will be strainlimited far before the intrinsic magnetic field limitations will beapproached, or possibly even before the magnetic field limitation ofNb3Sn can be surpassed. On a positive note, in a very promising recentresult from NIST on the axial strain dependence of the critical currentdensity in extremely well aligned YBCO, reversible behavior was observed.This result emphasizes the need for further conductor development,specifically for round wire Bi-2212, to generate a ...
Date: August 22, 2007
Creator: Godeke, Arno
Partner: UNT Libraries Government Documents Department

Injection and Extraction Lines for the ILC Damping Rings

Description: The current design for the injection and extraction linesintoand out of the ILC Damping Rings is presented as well as the designfor the abort line. Due to changes of the geometric boundary conditionsby other subsystems of the ILC, a modular approach has been used to beable to respond to recurring layout changes whilereusing previouslydesigned parts.
Date: June 20, 2007
Creator: Reichel, Ina
Partner: UNT Libraries Government Documents Department

Space-Charge Effects in the Super B-Factory LER

Description: Space-charge effects in the low-energy ring of the proposedSuper-B Factory are studied using a weak-strong model of dynamics asimplemented in the code Marylie/Impact (MLI). The impact of space chargeappears noticeable but our results suggest the existence of workableregions of the tune space where the design emittance is minimallyaffected. However, additional studies are recommended to fullysubstantiate this conclusion.
Date: January 31, 2007
Creator: Venturini, Marco
Partner: UNT Libraries Government Documents Department

Electroweak and QCD Results from the Tevatron

Description: The Tevatron collider has been remarkably successful and has so far delivered more than 11 fb{sup -1} of data to both the CDF and D0 experiments. Though the LHC has replaced the Tevatron as the world's most powerful collider, years of detector calibration, the huge size of the dataset and the nature of pp collisions will keep the Tevatron competitive in many selected topics in the near future. More than 10 fb{sup -1} of data has been collected by each experiment. Good understanding of the detector performance has been demonstrated by the high precision W boson mass ({Delta}M{sub W} = 31 MeV) and top quark mass ({Delta}M{sub t} = 1.06 GeV) measurements. We report the latest electroweak and QCD results from both experiments. Most analyses presented here used 4-6 fb{sup -1} of data.
Date: September 1, 2011
Creator: Zhu, Junjie
Partner: UNT Libraries Government Documents Department

The Future of Hadrons: The Nexus of Subatomic Physics

Description: The author offers brief observations on matters discussed at the XIV International Conference on Hadron Spectroscopy and explore prospects for hadron physics. Quantum chromodynamics (QCD) has been validated as a new law of nature. It is internally consistent up to very high energies, and so could be a complete theory of the strong interactions. Whether QCD is the final answer for the strong interactions is a subject for continuing experimental tests, which are being extended in experimentation at the Large Hadron Collider. Beyond the comparison of perturbative calculations with experiment, it remains critically important to test the confinement hypothesis by searching for free quarks, or for signatures of unconfined color. Sensitive negative searches for quarks continue to be interesting, and the definitive observation of free quarks would be revolutionary. Breakdowns of factorization would compromise the utility of perturbative QCD. Other discoveries that would require small or large revisions to QCD include the observation of new kinds of colored matter beyond quarks and gluons, the discovery that quarks are composite, or evidence that SU(3){sub c} gauge symmetry is the vestige of a larger, spontaneously broken, color symmetry. While probing our underlying theory for weakness or new openings, we have plenty to do to apply QCD to myriad experimental settings, to learn its implications for matter under unusual conditions, and to become more adept at calculating its consequences. New experimental tools provide the means for progress on a very broad front.
Date: September 1, 2011
Creator: Quigg, Chris
Partner: UNT Libraries Government Documents Department

Neutrino Oscillation Physics

Description: To complement the neutrino-physics lectures given at the 2011 International School on Astro Particle Physics devoted to Neutrino Physics and Astrophysics (ISAPP 2011; Varenna, Italy), at the 2011 European School of High Energy Physics (ESHEP 2011; Cheila Gradistei, Romania), and, in modified form, at other summer schools, we present here a written description of the physics of neutrino oscillation. This description is centered on a new way of deriving the oscillation probability. We also provide a brief guide to references relevant to topics other than neutrino oscillation that were covered in the lectures. Neutrinos and photons are by far the most abundant elementary particles in the universe. Thus, if we would like to comprehend the universe, we must understand the neutrinos. Of course, studying the neutrinos is challenging, since the only known forces through which these electrically-neutral leptons interact are the weak force and gravity. Consequently, interactions of neutrinos in a detector are very rare events, so that very large detectors and intense neutrino sources are needed to make experiments feasible. Nevertheless, we have confirmed that the weak interactions of neutrinos are correctly described by the Standard Model (SM) of elementary particle physics. Moreover, in the last 14 years, we have discovered that neutrinos have nonzero masses, and that leptons mix. These discoveries have been based on the observation that neutrinos can change from one 'flavor' to another - the phenomenon known as neutrino oscillation. We shall explain the physics of neutrino oscillation, deriving the probability of oscillation in a new way. We shall also provide a very brief guide to references that can be used to study some major neutrino-physics topics other than neutrino oscillation.
Date: June 1, 2012
Creator: Kayser, Boris
Partner: UNT Libraries Government Documents Department

B and D Physics from the Tevatron

Description: The CDF and D0 experiments at the Tevatron pp collider established that extensive and detailed exploration of the b-quark dynamics is possible in hadron collisions, with results competitive and supplementary to B-factories. In this paper we review the current state of Tevatron's heavy flavor measurements considering two main categories: searches for non standard model physics (results on rare decays and CP-violation) and determinations of standard model parameters (annihilation in B {yields} h{sup +}h{sup -} decays and {gamma} angle measurement through B {yields} DK modes).
Date: October 1, 2011
Creator: Squillacioti, Paola
Partner: UNT Libraries Government Documents Department