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A precision measurement of the branching ratio K{sup +} {r_arrow} {pi}{sup +}{pi}{sup 0}/K{sup +} {r_arrow} {mu}{sup +}{nu}{sub {mu}}

Description: A measurement of the branching ratio K{sup +} {r_arrow} {pi}{sup +}{pi}{sup 0}/K{sup +} {r_arrow} {mu}{sup +}{nu}{sub {mu}} was made using stopped kaons from p{anti p} annihilations at rest and a magnetic spectrometer to measure the momenta of the charged decay product to the 1% to 1.5% level. The determination is based on 45,500 events passing final data cuts. The resulting ratio is .3329 {+-} .0047 (statistical) {+-} .0010 (systematic).
Date: August 1, 1991
Creator: Usher, T.; Fero, M.; Gee, M.; Graf, N.A.; Mandelkern, M.; Shultz, D. et al.
Partner: UNT Libraries Government Documents Department

High energy ion collisions. Final technical report, December 14, 1995--March 17, 1997

Description: This grant supported one year of work on Relativistic Heavy Ion Collisions at the University of New Mexico. The Principal Investigator, an Adjunct Associate Professor at UNM, recruited a student (Mikhail Kopytine), sent him to CERN for several months to participate in the final data taking period of the NA44 experiment at CERN, then initiated analysis of the data collected during the run. A Hewlett-Packard workstation was purchased and Mr. Kopytine performed calibration, software development, and data analysis using it. A collaboration between Los Alamos National Laboratory and other faculty members at the University of New Mexico was begun, with the goal of working closely together on the PHENIX experiment for RHIC. At this time, a close collaboration continues, centered around the Muon tracking detectors for PHENIX. Station 1 of the tracking system is under construction at UNM, while stations 2 and 3 are the responsibility of LANL. The following accomplishments were made: (1) Participation in final data taking period of NA44; (2) Work on commissioning of aerogel Cerenkov trigger and performed offline analysis to demonstrate its performance; (3) Calibration of the uranium calorimeter in NA44 in preparation for Data Summary Tape production; (4) An optimized DST production for tapes with single pion, kaon, and proton triggers for Pb+Pb collisions was performed; (5) Analysis of pion and kaon distributions and production cross sections from Pb+Pb collisions; and (6) Participation in MVD development meetings and contributed to planning of the analysis software for MVD.
Date: December 31, 1997
Creator: Jacak, B. V.
Partner: UNT Libraries Government Documents Department

Spin physics with the PHENIX detector system

Description: The PHENIX experiment at RHIC has extended its scope to cover spin physics using polarized proton beams. The major goals of the spin physics at RHIC are elucidation of the spin structure of the nucleon and precision tests of the symmetries. Sensitivities of the spin physics measurements with the PHENIX detector system are reviewed.
Date: December 31, 1997
Creator: Saito, N. & Collaboration, PHENIX
Partner: UNT Libraries Government Documents Department

CP violation and rare decays

Description: After a brief essay on the current state of particle physics and possible approaches to the opportunities that have presented themselves, the author summarizes the contributions to the Third Workshop on Physics and Detectors for DA{Phi}NE that deal with CP Violation and Rare Decays.
Date: January 24, 2000
Creator: Quigg, C.
Partner: UNT Libraries Government Documents Department

Low energy supersymmetry phenomenology

Description: The authors summarize the current status and future prospects for low energy (weak scale) supersymmetry. In particular, they evaluate the capabilities of various e{sup +}e{sup {minus}}, p{anti p} and pp colliders to discover evidence for supersymmetric particles. Furthermore, assuming supersymmetry is discovered, they discuss capabilities of future facilities to disentangle the anticipated spectrum of superparticles, and, via precision measurements, to test mass and coupling parameters for comparison with various theoretical expectations. They comment upon the complementarity of proposed hadron and e{sup +}e{sup {minus}} machines for a comprehensive study of low energy supersymmetry.
Date: March 1, 1995
Creator: Baer, H.; Chen, C.H. & Bartl, A.
Partner: UNT Libraries Government Documents Department

The BRAHMS experiment at RHIC goals and status

Description: The BRAHMS experiment is designed to measure semi-inclusive spectra of charged hadron over a wide range of rapidity. It will yield information on particle production, both at central rapidity and in the baryon rich fragmentation region. Examples of measures for soft as well as for hard physics are presented. The present status of BRAHMS is discussed, as well as the plans for measurements in the first year of running at RHIC.
Date: December 1, 1998
Creator: Videbaek, F.
Partner: UNT Libraries Government Documents Department

DIRC, the internally reflecting ring imaging Cerenkov detector for BABAR: Properties of the quartz radiators

Description: A new type of detector for particle identification will be used in the BABAR experiment at the SLAC B Factory (PEP-II). This barrel region detector is called DIRC, an acronym for Detection of Internally Reflected Cerenkov (light). The DIRC is a Cerenkov ring imaging device which utilizes totally internally reflecting Cerenkov photons in the visible and near UV range. An extensive prototype program, demonstrated that the principles of operation are well understood, and that an excellent performance over the entire momentum range of the B factory is to be expected. The DIRC utilizes long, thin, flat quartz radiator bars (effective mean refractive index n{sub 1} = 1.474) with a rectangular cross section. In the present design the bars have transverse dimensions of 1.7 cm thick by 3.5 cm wide, and are about 4.90 m long. The length is achieved by gluing end-to-end four 1.225 m bars, that size being the longest high quality quartz bar currently available from industry. Several natural and synthetic fused silica candidate materials were tested for their optical properties and radiation hardness. In a Co{sup 60} source, samples were exposed to doses of up to 500 krad. While natural quartz materials showed significant absorption in the wavelength range of the Cerenkov photons after being exposed to only a few krad, the synthetic material proved to be sufficiently radiation hard. This led to the choice of Suprasil Standard and Spectrosil 2000 as bar material for the DIRC.
Date: July 1, 1997
Creator: Schwiening, J. & Collaboration, BABAR DIRC
Partner: UNT Libraries Government Documents Department

Evidence of K{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}}: The BNL E787 1995 result (How did we get here)

Description: The kaon was studied very thoroughly since its discovery some 50 years ago. In the study of charged kaon branching ratios, it was noticed that K{sup +} {r_arrow} {pi}{sup 0}e{sup +}{nu}{sub e} is allowed while K{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}} is not. The latter was then empirically classified as a forbidden decay, leading to the so called strangeness changing current rule. The decay K{sup +} {r_arrow} {pi}{sup 0}e{sup +}{nu}{sub e} is mediated by the strangeness changing charged current and its branching ratio is 4.8%. By contrast K{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}} is a strangeness changing neutral current, which is forbidden. In 1970, the GIM model was introduced to explain this effect and in 1974, Gaillard and Lee calculated the K{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}} branching ratio to be on the order of 10{sup {minus}10}. In the current theory, the K{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}} is mediated by a Flavor Changing Neutral Current (FCNC) in which the cancellation of the three quark generations should be complete down to second order except for the difference in the quark masses. The top quark is much heavier than the charm and up quarks, so that the cancellation is not complete. In other words, this decay is more dependent on the top sector. The measurement of K{sup +} {r_arrow}{pi}{sup +}{nu}{anti {nu}} branching ratio measures the modulus of the V{sub td} element of the CKM Matrix. The 1995 results of E787 were published in 1997. This report is focused on how the author achieved the goal of detecting events with such as small branching ratio.
Date: February 1, 1998
Creator: Chiang, I.H. & Collaboration, E787
Partner: UNT Libraries Government Documents Department

[High Energy Physics Program at the University of Alabama. Final report]

Description: The High Energy Physics group at University of Alabama is a member of the L3 collaboration studying e+e{minus} collisions near the Z{degree} pole at the LEP accelerator at CERN. About 2 million Z{degree} events have been accumulated and the experiment has been prolific in publishing results on the Z resonance parameters, the Z couplings to all leptons and quarks with mass less than half the Z mass, searches for new particles and interactions, and studies of strong interactions and/or weak charged current decays of the quarks and leptons abundantly produced in Z decays. The group is contributing to data analysis as well as to detector hardware. In particular, the authors are involved in a major hardware upgrade for the experiment, namely the design, construction and commissioning of a Silicon Microvertex Detector (SMD) which has successfully been installed for operation during the present grant period. The authors present here a report on their recent L3 activities and their plans for the next grant period of twelve months (April 1, 1994--March 31, 1995). Their main interests in data analysis are in the study of single photon final states and the physics made more accessible by the SMD, such as heavy flavor physics. Their hardware efforts continue to be concentrated on the high precision capacitive and optical alignment monitoring systems for the SMD and also includes gas monitoring for the muon system. They are also planning to participate in the coming upgrade of the L3 detector.
Date: October 1, 1993
Creator: Baksay, L. & Busenitz, J.K.
Partner: UNT Libraries Government Documents Department

Report of research activities and continuation request for the High Energy Physics Group at Southern Methodist University. Final report

Description: The main effort of the Southern Methodist University (SMU) group is devoted to the CLEO experiment at CESR concentrating on studies of the properties of the tau lepton and of the bottom and charm quarks. In addition to the data analysis they have initiated a major effort in the construction of the particle identification device (RICH) for the CLEO III upgrade. At SMU in Dallas, Thomas Coan, with the help of Jingbo Ye and five graduate students, is leading the construction of the RICH inner radiator. This task includes design and assembly of RICH mechanical structure and tests of the LiF crystals used to generate Cerenkov light. This second independent construction effort is still in its early stage. The initial project is to develop inter-chip connectors for the RICH front-end readout boards. In parallel, they work with a Cornell engineer on the design of a VME based interface board between the front-end data board and DAQ electronics. They expect this project to expand and to include the fabrication of the data interface board for the RICH readout starting in the spring of 1996.
Date: March 12, 1999
Creator: Stroynowski, R. & Coan, T.E.
Partner: UNT Libraries Government Documents Department

Measurement of sin2{beta} from J/{psi} K{sub s} decays

Description: The CP-violating parameter sin 2{beta} is directly measured using 110 pb{sup {minus}1} of data accumulated with the CDF detector at the Fermilab {anti p}p Tevatron collider operating at {radical}s = 1.8 TeV. The signal consists of 395 {+-} 31 B{sub d}{sup 0} {r{underscore}arrow} J/{psi} K{sub s} events. Three tagging methods are used to identify the type of B meson at production (B{sub d}{sup 0} or {anti B}{sub d}{sup 0}). From the CP asymmetry, sin 2{beta} is measured to be 0.79 {sub {minus}0.44}{sup +0.41}, consistent with Standard Model predictions. Sin 2{beta} is in the interval 0 {lt} sin2{beta} {lt} 1 at the 93% confidence level.
Date: January 24, 2000
Creator: Blocker, C.A.
Partner: UNT Libraries Government Documents Department

Run II jet physics: Proceedings of the Run II QCD and weak boson physics workshop

Description: The Run II jet physics group includes the Jet Algorithms, Jet Shape/Energy Flow, and Jet Measurements/Correlations subgroups. The main goal of the jet algorithm subgroup was to explore and define standard Run II jet finding procedures for CDF and D0. The focus of the jet shape/energy flow group was the study of jets as objects and the energy flows around these objects. The jet measurements/correlations subgroup discussed measurements at different beam energies; {alpha}{sub S} measurements; and LO, NLO, NNLO, and threshold jet calculations. As a practical matter the algorithm and shape/energy flow groups merged to concentrate on the development of Run II jet algorithms that are both free of theoretical and experimental difficulties and able to reproduce Run I measurements. Starting from a review of the experience gained during Run I, the group considered a variety of cone algorithms, and K{sub T} algorithms. The current understanding of both types of algorithms, including calibration issues, are discussed in this report along with some preliminary experimental results. The jet algorithms group recommends that CDF and D0 employ the same version of both a cone algorithm and a K{sub T} algorithm during Run II. Proposed versions of each type of algorithm are discussed. The group also recommends the use of full 4-vector kinematic variables whenever possible. The recommended algorithms attempt to minimize the impact of seeds in the case of the cone algorithm and preclustering in the case of the K{sub T} algorithm. Issues regarding precluster definitions and merge/split criteria require further study.
Date: May 11, 2000
Creator: al., Gerald C. Blazey et
Partner: UNT Libraries Government Documents Department

Neutrino oscillation appearance experiment using nuclear emulsion and magnetized iron

Description: This report describes an apparatus that could be used to measure both the identity and charge of an outgoing lepton in a charged current neutrino interaction. This capability in a massive detector would allow the most comprehensive set of neutrino oscillation physics measurements. By measuring the six observable transitions between initial and final state neutrinos, one would be able to measure all elements of the neutrino mixing matrix, as well as search for CP violation, and matter effects. If the measured matrix is not unitary, then one would also have an unambiguous determination of sterile neutrinos. Emulsion is considered as the tracking medium, and different techniques are discussed for the application of a magnetic field.
Date: January 24, 2000
Creator: Harris, D.A. & Para, A.
Partner: UNT Libraries Government Documents Department

Searches for new gauge bosons using the D0 detector

Description: We present the results of searches for additional gauge bosons beyond the W and Z bosons using the 1992-1993 Tevatron data set collected with the D0 detector. The signatures studied are W{prime} {yields} e{nu}, W{prime} {yields} {tau}{nu} with {tau} {yields} e{nu}{bar {nu}}, assuming stable neutrinos; W{sub R} {yields} e + X and W{sub R} {yields} eejj, assuming massive neutrinos; and Z{prime} {yields} ee. Lower limits on the W{prime} mass and Z{prime} mass at the 95% confidence level, and the mass exclusion contour in the W{sub R} mass vs. neutrino mass plane are presented.
Date: July 1, 1995
Creator: Abachi, S.; Abbott, B. & Abolins, M.
Partner: UNT Libraries Government Documents Department

Nuclear reaction studies with radioactive {sup 18}F beams at ATLAS

Description: The contribution of the {sup 18}F(p,{gamma}) reaction to the production of {sup 19}Ne which is the crucial isotope for the breakout from the hot CNO cycle into the rp process, has been investigated in experiments with {sup 18}F beams. Measurements of the cross sections for the {sup 18}F(p,{alpha}){sup 15}O and the {sup 18}F(p,{gamma}){sup 19}Ne reactions indicate that the contribution from the (p,{gamma}) route to the formation of {sup 19}Ne is small.
Date: July 1, 1996
Creator: Rehm, K.E.; Paul, M. & Roberts, A.D.
Partner: UNT Libraries Government Documents Department

Observation of the top quark

Description: The D{O} collaboration reports on a search for the Standard Model top quark in p{bar p} collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron, with an integrated luminosity of approximately 50 pb{sup -1}. We have searched for t{bar t} production in the dilepton and single-lepton decay channels, with and without tagging of b quark jets. We observe 17 events with an expected background of 3.8 {+-} 0.6 events. The probability for an upward fluctuation of the background to produce the observed signal is 2 x 10{sup -6} (equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. We conclude that we have observed the top quark and measure its mass to be 199{sub -21}{sup +19} (stat.) {+-}22 (syst.) GeV/c{sup 2}1 and its production cross section to be 6.4 {+-} 2.2 pb. Other decay channels are under study such as the t{bar t} to all-jets channel which might yield additional information about the top quark.
Date: October 1, 1995
Creator: Bantly, J.
Partner: UNT Libraries Government Documents Department

Overview of the GEM muon system cosmic ray test program at the SSCL

Description: Muon track resolution exceeding 75-{mu}m per plane is one of the main strengths of the GEM detector design, and will be crucial in searches for Higgs Bosons, heavy Z-Bosons, technicolor, and supersymmetry. Achieving this resolution coal requires improved precision in muon chambers and their alignment. A cosmic ray test stand known as the Texas Test Rio, (TTR) has been created at the SSCL for studying candidate GEM muon chamber technologies. Test results led to selecting Cathode Strip Chambers (CSC) as the GEM muon system baseline chamber technology.
Date: April 1, 1993
Creator: Milner, E.C.
Partner: UNT Libraries Government Documents Department

New particle searches at CDF

Description: One of the fundamental roles of a general purpose detector exploring, by means of increasing luminosity, higher and higher mass reach, is to search for new particles and exotic phenomena. This is a continuing effort for the CDF collaboration, and will report on several searches using about 20 pb{sup -1} from the 1992/93 run labelled {open_quotes}run 1a{close_quotes} and {approximately}50 of the 90 pb{sup -1} so far from the current {open_quotes}run 1b.{close_quotes} These are mostly preliminary analyses, typically using a total of 70 pb{sup -1}. Our limits on SUSY using missing E{sub T} with jets as well as three leptons are discussed elsewhere; results from the D0 collaboration are similar. I will discuss searches for additional vector bosons Z{prime} and W{prime}, second generation scalar leptoquarks, as well as a broad search for objects decaying into jet pairs, including b-tagged jet pairs. I will also describe two events which do not fit in comfortably with either the standard model or a phenomenologically motivated search.
Date: September 1, 1995
Creator: Nodulman, L.J.
Partner: UNT Libraries Government Documents Department

A limit on {sigma} {center_dot} BR (B{sub c}{sup {+-}} {yields} J/{psi} + {pi}{sup {+-}})/{sigma} {center_dot} BR(B{sub u}{sup {+-}} {yields} J/{psi} + K{sup {+-}}) in {radical}s = 1.8 TeV proton-antiproton collisions

Description: We report on the results of a search for the B{sub c} (b{bar c}) meson in the decay B{sub c}{sup +-} {yields} J/{psi} + {pi}{sup +-}. This search is guided by a control sample of decays of B{sub u} mesons to J/{psi} + K and uses {approx_equal} 75pb{sup -1} of data collected at the Collider Detector Facility (CDF) at Fermilab. The lifetime of the B{sub c} meson is unknown, so the 95% confidence level limit on {sigma} {center_dot} BR(B{sub c} {yields} {psi} + {pi})/{sigma} {center_dot} BR(B{sub u} {yields} {psi} + K) is obtained as a function of the B{sub c} lifetime.
Date: July 15, 1995
Creator: Abe, F.
Partner: UNT Libraries Government Documents Department

Finding the Higgs boson: A status report

Description: The search for the Higgs boson of the minimal Standard Model has been a major focus of experimental high energy physics for some years now. Here, the authors review the current experimental limits and discuss the prospects for finding the Higgs boson at future accelerators, such as LEPII and the LHC. They consider only the Standard Model Higgs boson. Since a null result which definitively excluded a Higgs boson below some mass scale would be extremely important, they emphasize the case where the Higgs boson is much heavier than the relevant collider energy (or where there is no Higgs boson at all). Many of the results given here are a summary of those obtained by the DPF Committee on Long Term Planning.
Date: August 16, 1995
Creator: Dawson, S.
Partner: UNT Libraries Government Documents Department

Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sqrt(sNN) = 200 GeV

Description: Identified mid-rapidity particle spectra of {pi}{sup {+-}}, K{sup {+-}}, and p({bar p}) from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (R{sub dAu}) between (p+ {bar p}) and charged hadrons (h) in the transverse momentum range 1.2 < p{sub T} < 3.0 GeV/c is measured to be 1.19 {+-} 0.05(stat) {+-} 0.03(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of (p + {bar p})/h in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.
Date: September 16, 2003
Creator: Adams, J.; Adler, C.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B.D. et al.
Partner: UNT Libraries Government Documents Department

Observation of the top quark

Description: The D0 collaboration reports on a search for the Standard Model top quark in p{bar p} collisions at {radical}s = 1.8 TeV at the Femlilab Tevatron, with an integrated luminosity of approximately 50 pb{sup {minus}1}. We have searched for t{bar t} production in the dilepton and single-lepton decay channels, with and without tagging of b quark jets. We observe 17 events with an expected background of 3.8 {plus_minus} 0.6 events. The probability for an upward fluctuation of the background to produce the observed signal is 2 {delta} 10{sup {minus}6} (equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. We conclude that we have observed the top quark and measure its mass to be 199{sub {minus}21}{sup +19} (stat.) {plus_minus}22 (syst.) GeV/c{sup 2} and its production cross section to be 6.4 {plus_minus} 2.2 pb.
Date: May 1, 1995
Creator: Thompson, J.
Partner: UNT Libraries Government Documents Department

The CDF-II time-of-flight detector

Description: A Time-of-Flight (TOF) detector, based on plastic scintillator and fine-mesh photomultiplier tubes, has been added to the CDF-II experiment. Since August 2001, the TOF system has been fully instrumented and integrated into the CDF-II data acquisition system. The TOF system will provide particle identification of low momentum charged pions, kaons and protons in -collisions. With a design resolution goal of about 100 ps, separation between charged kaons and pions is expected at the 2 sigma level for momenta below 1.6 GeV/c, which enhances CDF's b-flavor tagging capabilities. They describe the design of the TOF detector and discuss its on-line and off-line calibration. Some performance benchmarks using proton-antiproton collision data are presented.
Date: July 1, 2002
Creator: Cabera, S. et al.
Partner: UNT Libraries Government Documents Department

[Research in theoretical and experimental elementary particle physics. Final report]

Description: This report gives summaries of particle physics research conducted by different group members for Task A. A summary of work on the CLEO experiment and detector is included for Task B along with a list of CLEO publications. During the present grant period for Task C, the authors had responsibility for the design, assembly, and programming of the high-resolution spectrometer which looks for narrow peaks in the output of the cavity in the LLNL experiment. They successfully carried out this task. Velocity peaks are expected in the spectrum of dark matter axions on Earth. The computing proposal (Task S) is submitted in support of the High Energy Experiment (CLEO, Fermilab, CMS) and the Theory tasks.
Date: November 1, 1998
Partner: UNT Libraries Government Documents Department