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High energy physics studies. Progress report for Task D

Description: The major research activity of Task D has been collaboration in experiments E791 and E871 at Brookhaven National Laboratory. During the past year, the collaboration has published results of the second major run, nearly completed analysis of the final data from the experiment and reported some of these results in conferences. The authors now have a substantially better understanding of the potential backgrounds and systematic uncertainties in the experiment. This understanding is important for both the results to be derived from the present data and for future experiments. In addition, they have conducted extensive tests for the new experiment at Brookhaven. Their goal is to improve the sensitivity to rare decay modes of kaons by a factor of 20 over the final E791 result. In the coming year the authors will finish the final analysis of all data from the experiment, including a consistent reanalysis of all data and preparation of a Phys. Rev. D article describing the measurement. Assuming approval of E871 by BNL, they will finalize detailed design of the experiment and begin prototype testing and construction. In addition to the ongoing efforts on E791 and E871 at BNL, they have begun looking at the possibility of mounting a substantially improved experiment to be performed at the proposed Main Injector at Fermilab. This effort would be part of a Main Injector Kaon Facility. In this contract renewal request, they will review the current status of lepton flavor violation in K decays, summarize the status of the experiment, report in some detail on a number of the specific projects in which personnel supported by this contract have been involved, discuss the possibilities for future directions of the experiment, and list specific requests to the funding agency.
Date: August 1, 1991
Creator: Molzon, W.R.
Partner: UNT Libraries Government Documents Department

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

[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

Interesting aspects of the STAR detector and physics program

Description: The Solenoidal Tracker At RHIC (STAR) is a large acceptance collider detector scheduled to begin operation at the Relativistic Heavy Ion Collider (RHIC) in the fall of 1999. Simply stated, the physics goals of STAR are, (1) to study the behavior of strongly interacting matter at high energy density; (2) to search for signatures of a deconfined partonic phase of matter; and (3) to study the importance of spin as a fundamental property of QCD interactions and measure the spin-dependent parton distributions (gluon, valence quark, sea quark) of the proton. The detector design and methods of accomplishing the physics goals are addressed in this report.
Date: December 31, 1996
Creator: Hallman, T.J. & Collaboration, STAR
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

Evidence for B+ --> tau+ nu_tau Decays using Hadronic B Tags

Description: We present a search for the decay B{sup +} --> {tau}{sup +} {nu}{sub {tau}} using 467.8 x 10{sup 6} B{anti B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. We select a sample of events with on completely reconstructed B{sup -} in an hadronic decay mode (B{sup -} --> D{sup (*)0}X{sup -} and B{sup -} --> J/{psi} X{sup -}). We examine the rest of the event to search for a B{sup +} --> {tau}{sup +} {nu}{sub {tau}} decay. We identify the {tau}{sup +} lepton in the following modes: {tau}{sup +} --> e{sup +} {nu}{sub e}{anti {nu}}{sub {tau}}, {tau}{sup +} --> {mu}{sup +} {nu}{sub {mu}}{anti {nu}}{sub {tau}}, {tau}{sup +} --> {pi}{sup +}{anti {nu}}{sub {tau}} and {tau}{sup +} --> {rho}{anti {nu}}{sub {tau}}. We find an excess of events with respect to expected background, which excludes the null signal hypothesis at the level of 3.3 {sigma} and can be converted to a branching fraction central value of B(B{sup +} --> {tau}{sup +} {nu}{sub {tau}})= (1.80{sup + 0.57}{sub - 0.54}(stat.) {+-} 0.26 (syst.)) x 10{sup -4}.
Date: August 11, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

Compact, Low-power and Precision Timing Photodetector Readout

Description: Photodetector readout for next generation high event rate particle identification and single-photon detection requires a digitizer capable of integrated recording of dense arrays of sensor elements with high analog bandwidth (precision timing) and large record depth, in a cost-effective, compact and low-power way. Simply stated, one cannot do better than having a high-fidelity 'oscilloscope on a chip' for every sensor channel. A firs version of the Buffered Large Analog Bandwidth (BLAB1) ASIC has been designed based upon the lessons learned from the development of the Large Analog Bandwidth Recorder and Digitizer with Ordered Readout (LABRADOR) ASIC. While this LABRADOR ASIC has been very successful and forms the readout basis of a generation of new, large-scale radio neutrino detectors, its limited sampling depth is a major drawback. To address this shortcoming, a prototype intended for photodetector readout has been designed and fabricated with 64k deep sampling at multi-GSa/s operation. An evaluation system has been constructed for instrumentation of Time-Of-Propagation (TOP) and focusing DIRC prototypes and test results will be reported.
Date: June 14, 2011
Creator: Varner, Gary S.; Ruckman, Larry L.; U., /Hawaii; Schwiening, Jochen; Vavra, Jaroslav & /SLAC
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 production of {pi}{sup {+-}}, K{sup {+-}}, p, k{sup 0} and {Lambda}{sup 0} in hadronic Z{sup 0} decays

Description: The authors have measured production fractions and spectra for {pi}{sup {+-}}, K{sup {+-}} and p, and production spectra for K{sup 0} and {Lambda}{sup 0} in both hadronic Z{sup 0} decays and a Z{sup 0} {yields} light quark (uds) subset at SLD. The SLD Cherenkov Ring Imaging Detector was used to identify charged hadrons. The CCD vertex detector was used to select the enriched uds sample. For the global sample, the results are consistent with previous experiments. The authors observe a clear flavor dependence in production spectra, but only a small effect in hadron fractions and {xi} = ln(1/x{sub p}) peak positions.
Date: August 1, 1995
Creator: Baird, K. & Collaboration, SLD
Partner: UNT Libraries Government Documents Department

Developement of a same-side kaon tagging algorithm of B^0_s decays for measuring delta m_s at CDF II

Description: The authors developed a Same-Side Kaon Tagging algorithm to determine the production flavor of B{sub s}{sup 0} mesons. Until the B{sub s}{sup 0} mixing frequency is clearly observed the performance of the Same-Side Kaon Tagging algorithm can not be measured on data but has to be determined on Monte Carlo simulation. Data and Monte Carlo agreement has been evaluated for both the B{sub s}{sup 0} and the high statistics B{sup +} and B{sup 0} modes. Extensive systematic studies were performed to quantify potential discrepancies between data and Monte Carlo. The final optimized tagging algorithm exploits the particle identification capability of the CDF II detector. it achieves a tagging performance of {epsilon}D{sup 2} = 4.0{sub -1.2}{sup +0.9} on the B{sub s}{sup 0} {yields} D{sub s}{sup -} {pi}{sup +} sample. The Same-Side Kaon Tagging algorithm presented here has been applied to the ongoing B{sub s}{sup 0} mixing analysis, and has provided a factor of 3-4 increase in the effective statistical size of the sample. This improvement results in the first direct measurement of the B{sub s}{sup 0} mixing frequency.
Date: June 1, 2006
Creator: Menzemer, Stephanie & U., /Heidelberg
Partner: UNT Libraries Government Documents Department

Development of a Focusing DIRC

Description: Benefiting from the recent introduction of new fast vacuum-based photon detectors with a transit time spread of {sigma}{sub TTS} {approx} 30-150 ps, we are developing a novel RICH detector capable of correcting the chromatic error through good time measurements; we believe that this is the first time such a technique has been demonstrated. We have built and successfully tested a particle identification detector called ''Focusing DIRC''. The concept of the prototype is based on the BaBar DIRC, with several important improvements: (a) much faster pixelated photon detectors based on Burle MCP-PMTs and Hamamatsu MaPMTs, (b) a focusing mirror which allows the photon detector to be smaller and less sensitive to background in future applications, (c) electronics allowing the measurement of single photon timing to better than {sigma} {approx} 100-200ps, which allows a correction of the chromatic error. The detector was tested in a SLAC 10GeV/c electron test beam. This detector concept could be used for particle identification at Super B-factory, ILC, GlueX, Panda, etc.
Date: December 12, 2006
Creator: Benitez, J.; Bedajanek, I.; Leith, D.W.G.S.; Mazaheri, G.; Ratcliff, B.; Suzuki, K. et al.
Partner: UNT Libraries Government Documents Department

Status of the Fast Focusing DIRC (fDIRC)

Description: We have built and successfully tested a novel particle identification detector concept, the Fast Focusing DIRC (fDIRC). The prototype's concept is based on the BaBar DIRC with several important improvements: (a) much faster pixelated photon detectors based on Burle MCP-PMTs and Hamamatsu MaPMTs, (b) a focusing mirror allowing a smaller photon detector, reducing the sensitivity to backgrounds in future applications, (c) electronics capable of measuring the single photon resolution to better than {sigma} {approx} 100-200ps. The fDIRC is the first RICH detector to successfully correct the chromatic error by timing.
Date: February 4, 2008
Creator: Benitez, J.; Leith, D.W.G.S.; Mazaheri, G.; Ratcliff, B.N.; Schwiening, J.; Vavra, J. et al.
Partner: UNT Libraries Government Documents Department

Liquid-Argon Time Projection Chambers in the U.S

Description: Liquid Argon Time Projection Chamber (LAr TPC) detectors are ideally suited for studying neutrino interactions and probing the parameters that characterize neutrino oscillations. The ability to drift ionization particles over long distances in purified argon and to trigger on abundant scintillation light allows for excellent particle identification and triggering capability. Recent U.S. based work in the development of LAr TPC technology for massive kiloton size detectors will be discussed in this talk, including details of the ArgoNeuT (Argon Neutrino Test) test-beam project, which is a 175 liter LAr TPC exposed to Fermilab's NuMI neutrino beamline.
Date: October 1, 2009
Creator: Soderberg, M.
Partner: UNT Libraries Government Documents Department

A proposal to study particle production spectra and multiplicities in high energy hadron-hadron collisions, and for a beam survey and quark search

Description: We propose an experimental study at the new 500 GeV accelerator of the differential cross-section for particle production in hadron-hadron collisions. The projectile, and the observed single particle, will range over all combinations of positive and negative {pi}, K and p, with momenta extending up to the highest available. Enough of the secondary particle momentum range will be covered to permit us to determine by integration the multiplicity of the produced particle. Single particles will be detected in a simple spectrometer consisting of wire chambers and a small bending magnet. The configuration of the spectrometer components will be variable so that the overall spectrometer length can be kept proportional to the secondary momentum. The momentum resolution {male}P/P = {+-}0.8% and the invariant phase space acceptance P{sup 2}d{Omega}dP/E = 1.3x10{sup -3} (GeV/c){sup 2} will then be the same at all momenta. Particle identification will be by means of threshold Cherenkov counters, with 10{sup 4}: 1 rejection up to at least 250 GeV/c. Our experimental arrangement is thought to be simple and yet powerful, and we propose its use initially with incident protons and a nuclear target for a beam survey and quark search. Subsequent measurements will be carried out with a hydrogen target in a high intensity secondary beam.
Date: June 15, 1970
Creator: Beier, E.W.; Kreinick, D.L.; Weisberg, H. & U., /Pennsylvania
Partner: UNT Libraries Government Documents Department

MicroBooNE: A New Liquid Argon Time Projection Chamber Experiment

Description: Liquid Argon Time Projection Chamber detectors are well suited to study neutrino interactions, and are an intriguing option for future massive detectors capable of measuring the parameters that characterize neutrino oscillations. These detectors combine fine-grained tracking with calorimetry, allowing for excellent imaging and particle identification ability. In this talk the details of the MicroBooNE experiment, a 175 ton LArTPC which will be exposed to Fermilab's Booster Neutrino Beamline starting in 2011, will be presented. The ability of MicroBooNE to differentiate electrons from photons gives the experiment unique capabilities in low energy neutrino interaction measurements.
Date: October 1, 2009
Creator: Soderberg, M.
Partner: UNT Libraries Government Documents Department

ArgoNeuT: A Liquid Argon Time Projection Chamber Test in the NuMI Beamline

Description: Liquid Argon Time Projection Chamber detectors are ideally suited for studying neutrino interactions and probing the parameters that characterize neutrino oscillations. The ability to drift ionization particles over long distances in purified argon and to trigger on abundant scintillation light allows for excellent particle identification and triggering capability. In these proceedings the details of the ArgoNeuT test-beam project will be presented after a brief introduction to the detector technique. ArgoNeuT is a 175 liter detector exposed to Fermilab's NuMI neutrino beamline. The first neutrino interactions observed in ArgoNeuT will be presented, along with discussion of the various physics analyses to be performed on this data sample.
Date: October 1, 2009
Creator: Soderberg, M.
Partner: UNT Libraries Government Documents Department

Status of MICE

Description: Muon ionization cooling is the only practical method for preparing high-brilliance beams needed for a neutrino factory or muon collider. The muon ionization cooling experiment (MICE) under development at the Rutherford Appleton Laboratory comprises a dedicated beamline to generate a range of input emittance and momentum, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. A first measurement of emittance is performed in the upstream magnetic spectrometer with a scintillating-fiber tracker. A cooling cell will then follow, alternating energy loss in liquid hydrogen with RF acceleration. A second spectrometer identical to the first and a particle identification system will measure the outgoing emittance. Plans for measurements of emittance and cooling are described.
Date: November 1, 2008
Creator: Bross, A. D. & Kaplan, D. M.
Partner: UNT Libraries Government Documents Department

Construction and Performance of the BaBar DIRC

Description: The new type of ring-imaging Cherenkov detector technology called DIRC (an acronym for Detection of Internally Reflected Cherenkov (Light)) has been used successfully for hadronic particle identification in the BABAR experiment at the B Factory (PEP-II) located at the SLAC National Accelerator Laboratory. This paper describes the R&D for and the construction of the DIRC radiator bars and the performance of the DIRC during more than eight years of B Factory operation.
Date: October 30, 2009
Creator: Schwiening, Jochen
Partner: UNT Libraries Government Documents Department

Search for third generation vector leptoquarks in 1.96 TeV proton-antiproton collisions

Description: The CDF experiment has searched for production of a third generation vector leptoquark (VLQ3) in the di-tau plus di-jet channel using 322 pb{sup -1} of Run II data. We review the production and decay theory and describe the VLQ3 model we have used as a benchmark. We study the analysis, including the data sample, triggers, particle identification, and event selection. We also discuss background estimates and systematic uncertainties. We have found no evidence for VLQ3 production and have set a 95% C.L. upper limit on the pair production cross section {sigma} to 344 fb, and exclude VLQ3 in the mass range m{sub VLQ3} > 317 GeV/c{sup 2}, assuming Yang-Mills couplings and Br(LQ3 {yields} b{tau}) = 1. If theoretical uncertainties on the cross section are taken into account, the results are {sigma} < 353 fb and m{sub VLQ3} > 303 GeV/c{sup 2}. For a VLQ3 with Minimal couplings, the upper limit on the cross section is {sigma} < 493 fb ({sigma} < 554 fb) and the lower limit on the mass is m{sub VLQ3} > 251 GeV/c{sup 2} (m{sub VLQ3} > 235 GeV/c{sup 2}) for the nominal (1{sigma} varied) theoretical expectation.
Date: February 1, 2007
Creator: Akimoto, Takashi
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

A neural jet charge tagger for the measurement of the B/s0 anti-B/s0 oscillation frequency at CDF

Description: A Jet Charge Tagger algorithm for b-flavour tagging for the measurement of {Delta}m{sub s} at CDF has been presented. The tagger is based on a b-track probability variable and a b-jet probability variable, both obtained by combining the information available in b{bar b} events with a Neural Network. The tagging power measured on data is 0.917 {+-} 0.031% e+SVT sample; 0.938 {+-} 0.029% {mu}+SVT sample which is {approx}30% larger than the cut based Jet Charge Tagger employed for the B{sub s}{sup 0} mixing analysis presented by CDF at the Winter Conferences 2005. The improved power of the tagger is due to the selection of the b-jet with a Neural Network variable, which uses correlated jet variables in an optimal way. The development of the track and jet probability has profited from studies performed on simulated events, which allowed to understand better the features of b{bar b} events. For the first time in the CDF B group a Monte Carlo sample comprising flavour creation and additional b{bar b} production processes has been examined and compared to Run II data. It has been demonstrated that a Monte Carlo sample with only flavour creation b{bar b} production processes is not sufficient to describe b{bar b} data collected at CDF. The sample with additional processes introduced in this thesis is thus essential for tagging studies. Although the event description is satisfactory, the flavour information in the Monte Carlo sample differs with respect to data. This difference needs to be clarified by further studies. In addition, the track and the jet probabilities are the first official tools based on Neural Networks for B-Physics at CDF. They have proven that the simulation is understood to such an advanced level that Neural Networks can be employed. Further work is going on in this direction: a Soft Electron ...
Date: July 1, 2005
Creator: Lecci, Claudia
Partner: UNT Libraries Government Documents Department

Time-of-flight measurements at the LAMPF low-energy pion channel

Description: Particle identification by time-of-flight techniques was carried out using flight paths between two scintillation counters and between one such counter and the 200-MHz rf structure of the primary proton beam striking the meson production target. With the low-energy pion channel at 103 MeV/c, the two- counter technique yielded clean separation of pions, muons, and electrons. At 195 MeV/c, the rf technique measured the energy resolution of the primary proton beam to be as good as 0.14% FWHM. (auth)
Date: March 1, 1974
Creator: Cooper, M.D.
Partner: UNT Libraries Government Documents Department