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Experimental overview of axion searches

Description: Experimental methods to search for the ``invisible axion`` (f{sub a} {much_gt} 250 GeV) are reviewed. The report focuses on the axion-photon coupling, both for laboratory experiments as well as those looking for stellar or cosmologically produced axions. The conclusion is that while the axion-photon mixing in principle would permit laboratory axion searches which are broadband in mass, in fact no such experiment could have the sensitivity to the axion, where m{sub afa} {approx} m{sub {pi}f{pi}}. The only experiments which promise to have any chance to find the axion are the microwave cavity experiments, which presume axions to constitute our galactic halo dark matter. The conversion of axions into a monochromatic microwave signal in a resonant circuit affords the experiment the extraordinary sensitivity required to see the axion, at the expense of being narrow-band in mass, i.e. a tuning experiment. Two such efforts are underway in the world.
Date: June 28, 1995
Creator: van Bibber, K.
Partner: UNT Libraries Government Documents Department

Panel discussion on the future of hadron spectroscopy

Description: This contribution addresses two of the questions which were submitted to the panel on future developments in light hadron spectroscopy. Specifically, these were the extent to which glueball spectroscopy should be explored and how far it is appropriate to continue experimental studies of the light hadron spectrum. The authors suggest that at a minimum three particular glueball states should be identified, that hybrids should also be identified, and that experiments on hadrons should continue for as long as the theoretical community remains unable to predict their outcome.
Date: December 31, 1995
Creator: Barnes, T.
Partner: UNT Libraries Government Documents Department

B Decay Studies at SLD

Description: We present three preliminary results from SLD on B decays: an inclusive search for the process b {r_arrow} s gluon, a measurement of the branching ratio for the process B {r_arrow} D{bar D}X, and measurements of the charged and neutral B lifetimes. All three measurements make use of the excellent vertexing efficiency and resolution of the CCD Vertex Detector and the first two make use of the excellent particle identification capability of the Cherenkov Ring Imaging Detector. The b {r_arrow} sg analysis searches for an enhancement of high momentum charged kaons produced in B decays. Within the context of a simple, Jetset-inspired model of b {r_arrow} sg, a limit of B(b {r_arrow} sg) < 7.6% is obtained. The B(B {r_arrow} D{bar D}X) analysis reconstructs two secondary vertices and uses identified charged kaons to determine which of these came from charm decays. The result of the analysis is B(B {r_arrow} D{bar D}X) = (16.2 {+-} 1.9 {+-} 4.2)%. The results of the lifetime analysis are: {tau}{sub B{sup +}} = 1.686 {+-} 0.025 {+-} 0.042 ps, {tau}{sub B{sup 0}} = 1.589 {+-} 0.026 {+-} 0.055 ps and {tau}{sub B{sup +}}/{tau}{sub B{sup 0}} = 1.061 {+-} 0.031/0.029 {+-} 0.027.
Date: March 19, 1999
Creator: Convery, Mark R
Partner: UNT Libraries Government Documents Department

The CDF Time of Flight Detector

Description: A new Time of Flight (TOF) detector based on scintillator bars with fine-mesh photomultipliers at both ends has been in operation since 2001 in the CDF experiment. With a design resolution of 100 ps, the TOF can provide separation between K{sup +-} and {pi}{sup +-} in p{bar p} collisions at the 2{omega} level for low momentum, which enhances b flavor tagging capabilities. Because of its very fast response, the TOF is an excellent triggering device, and it is used to trigger on highly ionizing particles, multiple minimum ionizing particles and cosmic rays. Particle identification is achieved by comparing the time-of-flight of the particle measured by the TOF to the time expected for a given mass hypothesis. In order to obtain the resolution necessary for particle ID, optimal calibrations are critical. This paper describes the TOF detector, its calibration procedure, the achieved resolution, the long term operation performances and some of the first results from data analysis using this detector.
Date: January 6, 2004
Creator: al., S. Cabrera et
Partner: UNT Libraries Government Documents Department

The CDFII time-of-flight detector and impact on beauty flavor tagging

Description: Following the successful RunI from 1992 to 1996, the CDF detector has undergone a major upgrade [1] for the RunII which begun in March 2001. The approval for the addition of a Time-of-Flight detector was granted in January 1999. The installation of the TOF detector was completed in August 2001 and its data has been included in the CDFII readout since then. The primary physics motivation for TOF is to complement and enhance the particle identification capability provided by the central drift chamber (COT) since it distinguishes K{sup {+-}} and {pi}{sup {+-}} in the momentum region of their cross-over in dE=dX. With an expected time-of-flight resolution of 100 ps, the TOF system will be capable of identifying charged kaons from pions by their flight time difference with at least two standard deviation separation up to kaon momenta of 1.6 GeV/c. Such an addition results in an enhancement of the b flavor identification power, crucial to improve the statistical precision in CP violation and B{sub s} mixing measurements.
Date: December 3, 2002
Creator: al., C. Grozis et
Partner: UNT Libraries Government Documents Department

Extracting longitudinal shower development information from crystal calorimetry plus tracking

Description: We present an approach to derive longitudinal shower development information from the longitudinally unsegmented BABAR electromagnetic calorimeter by using tracking information. Our algorithm takes advantage of the good three-dimensional tracking resolution of BABAR, which provides an independent geometric constraint on the shower as measured in the BABAR crystal calorimeter. We show that adding the derived longitudinal shower development information to standard particle identification algorithms significantly improves the low-momentum separation of pions from electrons and muons. We also verify that the energy dependence of the electromagnetic shower development we measure is consistent with the prediction of a standard electromagnetic shower model.
Date: November 1, 2007
Creator: Brown, David; Brown, D.N.; Ilic, J. & Mohanty, G.B.
Partner: UNT Libraries Government Documents Department

DIRC Dreams: Research Directions for the Next Generation of Internally Reflected Imaging Counters

Description: Some conceptual design features of the total internally reflecting,imaging Cherenkov counter (DIRC) are described. Limits of the DIRC approach to particle identification, and a few features of alternative DIRC designs, are briefly explored.
Date: August 17, 1999
Creator: Ratcliff, Blair N
Partner: UNT Libraries Government Documents Department

MEGA -- A search for {mu} {r_arrow} e{gamma}

Description: The MEGA experiment is a search for the decay {mu} {r_arrow} e{gamma}. Even though there is no fundamental reason to expect lepton number to be a conserved quantity, processes such as {mu} {r_arrow} e{gamma} have not been observed. (The present upper limit for the branching ratio for {mu} {r_arrow} e{gamma} is 4.9 x 10{sup {minus}11}.) The minimal standard model of electroweak interactions, which is enormously successful, builds in lepton number conservation. However, the decay {mu} {r_arrow} e{gamma} is expected in many extensions to the standard model, in particular in supersymmetry models. The experimental signature for {mu} {r_arrow} e{gamma} from decays at rest is the observation of a positron and photon, each of 52.8 MeV , that are back-to-back, in time coincidence, and originate from a common spatial point. The MEGA detector consists of two spectrometers designed to measure the kinematic characteristics of positrons and photons to search for events with this signature. The primary difficulty in the analysis of these data has been the development of reconstruction algorithms that balance efficiency and resolution. Also, many calibrations and corrections are needed to get optimum resolutions. Most surviving candidate events are accidentals. Results of analysis are given.
Date: December 1, 1998
Creator: Mischke, R. E.
Partner: UNT Libraries Government Documents Department

Searches with taus at the Tevatron

Description: We discuss tau identification techniques at hadron colliders, and present the measurements and the searches performed so far. We report on top quark pair production in the decay channel containing at least one tau lepton. Also, we present results dedicated to searches for new particles, with taus in the final state. We present a search for the charged Higgs boson in the tau decay channel, as well as for the leptoquark family containing tau leptons. Finally, we indicate the capabilities of detecting and triggering on tau leptons in the future collider run.
Date: April 29, 1999
Creator: Gallinaro, M.
Partner: UNT Libraries Government Documents Department

Progress on Development of the New FDIRC PID Detector

Description: We present a progress status of a new concept of PID detector called FDIRC, intended to be used at the SuperB experiment, which requires {pi}/K separation up to a few GeV/c. The new photon camera is made of the solid fused-silica optics with a volume 25x smaller and speed increased by a factor of ten compared to the BaBar DIRC, and therefore will be much less sensitive to electromagnetic and neutron background
Date: August 3, 2012
Creator: Vavra, Jerry
Partner: UNT Libraries Government Documents Department

Search for anomalous WW and WZ production at D0

Description: We present a preliminary result from a search for anomalous WW and WZ production in p{bar p} collisions at {radical}s = 1.8 TeV using p{bar p} {yields} e{nu}jj events observed during the 1992-1993 run of the Fermilab Tevatron collider. A fit to the p{sub T} spectrum of W(e{nu}) yields direct limits on the CP-conserving anomalous WW{gamma} and WWZ coupling parameters of -0.89 < {Delta}{kappa} < 1.07 ({lambda} = 0) and -0.66 < {lambda} < 0.67 ({Delta}{kappa} = 0) at the 95% confidence level, assuming that the WWZ coupling parameters are equal to the WW{gamma} coupling parameters, and a form factor scale {Lambda} = 1.5 TeV.
Date: July 1, 1995
Creator: Abachi, S.
Partner: UNT Libraries Government Documents Department

The Focusing DIRC - the First RICH Detector toCorrect the Chromatic Error by Timing, and the Development of a New TOFDetector Concept

Description: We have built and successfully tested a novel particle identification detector called Focusing DIRC. The prototype's concept is based on the BaBar DIRC with several important improvements: (a) much faster pixilated photon detectors based on Burle MCP-PMT and Hamamatsu MaPMT, (b) mirror allowing to make the photon detector smaller and less sensitive to background in future applications, (c) electronics allowing to measure the single photon resolution to better than {sigma} {approx} 100-200ps, which allows a correction of the chromatic error. While testing the timing resolution limits of a 64-pixel MCP-PMT with 10 mm MCP holes, we have achieved a timing resolution of {sigma} {approx} 30ps with single photoelectrons. In this paper we further investigate limits of the timing resolution with this particular detector.
Date: September 12, 2007
Creator: Va'vra, Jaroslav; Benitez, Jorge A.; Leith, David W.G.S.; Mazaheri, Gholamali; Ratcliff, Blair N.; Schwiening, Jochen et al.
Partner: UNT Libraries Government Documents Department

CCpi0 Event Reconstruction at MiniBooNE

Description: We describe the development of a fitter to reconstruct {nu}{sub {mu}} induced Charged-Current single {pi}{sup 0} (CC{pi}{sup 0}) events in an oil Cerenkov detector (CH{sub 2}). These events are fit using a generic muon and two photon extended track hypothesis from a common event vertex. The development of ring finding and particle identification are described. Comparisons between data and Monte Carlo are presented for a few kinematic distributions.
Date: September 1, 2009
Creator: Nelson, Robert H. & U., /Colorado
Partner: UNT Libraries Government Documents Department

Proposal for Research and Development: Vertexing, Tracking, and Data Acquisition for the Bottom Collider Detector

Description: The authors propose a program of research and development into the detector systems needed for a B-physics experiment at the Fermilab p-{bar p} Collider. The initial emphasis is on the critical issues of vertexting, tracking, and data acquisition in the high-multiplicity, high-rate collider environment. R and D for the particle-identification systems (RICH counters, TRD's, and EM calorimeter) will be covered in a subsequent proposal. To help focus their efforts in a timely manner, they propose the first phase of the R and D should culminate in a system test at the C0 collider intersect during the 1990-1991 run: a small fraction of the eventual vertex detector would be used to demonstrate that secondary-decay vertices can be found at a hadron collider. The proposed budget for the r and D program is $800k in 1989, $1.5M in 1990, and $1.6M in 1991.
Date: January 1, 1989
Creator: Castro, H.; Gomez, B.; Rivera, F.; Sanabria, J.-C.; U., /Los Andes; Yager, P. et al.
Partner: UNT Libraries Government Documents Department

Search for light top squarks with the D{O} detector

Description: We present preliminary results of a search for pair produced top squarks, the supersymmetric partners to the top quark, under the assumption that the two-body decay {bar t}{sub 1} {yields} b{bar W}{sub 1} and three-body decay {bar t}{sub 1} {yields} bW{bar Z}{sub 1} are kinematically forbidden. This scenario is realized if {bar t}{sub 1} is considerably lighter than all other squarks as well as {bar W}{sub 1}, all {bar v}s, and the top quark. Such light top squarks will dominantly decay via {bar t}{sub 1} {yields} c{bar Z}{sub 1} yielding a signal of two acollinear jets with (E){sub T}. The data reported here were taken during the 1992-1993 run of the D0 detector at the Fermilab Tevatron p{bar p} collider operating at {radical}s = 1.8 TeV.
Date: July 1, 1995
Creator: Abachi, S.
Partner: UNT Libraries Government Documents Department

The inclusive jet cross section at {radical}s = 630 GeV at D0

Description: The authors present a preliminary measurement of the cross section for central inclusive jet production at {radical}s = 630 GeV using {approximately} 400 nb{sup {minus}1} of data collected during the December 1995 Fermilab collider run at D0. These results are compared to NLO QCD predictions.
Date: September 1, 1996
Creator: Krane, J.
Partner: UNT Libraries Government Documents Department

The mechanism of open-flavor strong decays

Description: In this contribution the author discusses models of two-body strong hadron decays. These models are expected to play a vital role in future attempts to identify unconventional hadrons such as glueballs and hybrids, through accurate predictions of the decay modes of conventional q{anti q} states. First, he reviews the most commonly used decay model, which is the {sup 3}P{sub 0} model developed by Micu and LeYaouanc et al., and show some of its successful predictions. Predictions of the {sup 3}P{sub 0} model for some newly discovered states are also given. Finally he discusses some attempts to identify the fundamental QCD process which underlies q{anti q} pair production in the {sup 3}P{sub 0} model. His results indicate that the dominant q{anti q} pair production process is usually pair production through the linear scalar confining interaction. Pair production from OGE in most cases is found to be a smaller amplitude, with the notable exception of {sup 3}P{sub 0} {yields} {sup 1}S{sub 0} decays such as f{sub 0}(q{anti q}) {yields} {pi}{pi}.
Date: December 1995
Creator: Barnes, T.
Partner: UNT Libraries Government Documents Department

Fast Drift CRID with GEM

Description: The only available technique at the present time, to perform particle identification up to 40-50 GeV/c in a 4{pi} solenoidal geometry using the Cherenkov ring imaging method is the use of gaseous detectors tilled with either TMAE or TEA photocathodes, and a combination of the gaseous, and solid or liquid radiators. If one would consider building such a device, one may want to investigate alternative methods of building a single-electron detector. This paper investigates the feasibility of using the GEM together with a simple MWPC detector employing 33 {micro}m diameter carbon wires to obtain a second coordinate. The results are compared to the CRID single-electron detector.
Date: May 20, 1999
Creator: Va'Vra, Jaroslav
Partner: UNT Libraries Government Documents Department

My recollections as a physicist

Description: This presentation is a talk presented by the author at a Physics Symposium of the 50th anniversary of the Taiwan University, in December 1996. The author describes how he became a physicist, and then presents a brief outline of his professional career, most of which has centered at Stanford Linear Accelerator Center. He was involved in the discovery of the {tau} lepton, and in studies of CP violation through decay of the {tau}, in addition to studies of semileptonic decay of t, B, D, K, and {pi}.
Date: March 1, 1997
Creator: Tsai, Yung-su
Partner: UNT Libraries Government Documents Department

Precision measurements in supersymmetry

Description: Supersymmetry is a promising framework in which to explore extensions of the standard model. If candidates for supersymmetric particles are found, precision measurements of their properties will then be of paramount importance. The prospects for such measurements and their implications are the subject of this thesis. If charginos are produced at the LEP II collider, they are likely to be one of the few available supersymmetric signals for many years. The author considers the possibility of determining fundamental supersymmetry parameters in such a scenario. The study is complicated by the dependence of observables on a large number of these parameters. He proposes a straightforward procedure for disentangling these dependences and demonstrate its effectiveness by presenting a number of case studies at representative points in parameter space. In addition to determining the properties of supersymmetric particles, precision measurements may also be used to establish that newly-discovered particles are, in fact, supersymmetric. Supersymmetry predicts quantitative relations among the couplings and masses of superparticles. The author discusses tests of such relations at a future e{sup +}e{sup {minus}} linear collider, using measurements that exploit the availability of polarizable beams. Stringent tests of supersymmetry from chargino production are demonstrated in two representative cases, and fermion and neutralino processes are also discussed.
Date: May 1, 1995
Creator: Feng, J.L.
Partner: UNT Libraries Government Documents Department

Results on top quark production from D0

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 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 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.){plus_minus}22 (syst.) GeV/c{sup 2} and its production cross section to be 6.4 {plus_minus} 2.2 pb.
Date: August 1, 1995
Creator: Wimpenny, S.J.
Partner: UNT Libraries Government Documents Department

Preliminary results from IMB3 muon/electron identification tests at KEK

Description: A test has been conducted at KEK, Japan using beams of electrons and muons in a 1 kiloton water Cherenkov detector instrumented with IMB3 phototubes and electronics to evaluate IMB`s algorithms for identifying electrons and muons. This identification is important because the IMB3 detector`s results on the atmospheric neutrino anomaly depend on the proper identification of the electrons and muons produced in neutrino charged-current interactions. Preliminary results are presented.
Date: September 1, 1995
Creator: Bratton, C.B.; Breault, J. & Conner, Z.
Partner: UNT Libraries Government Documents Department

The search for proton decay

Description: The conservation of the quantum number called baryon number, like lepton (or family) number, is an empirical fact even though there are very good reasons to expect otherwise. Experimentalists have been searching for baryon number violating decays of the proton and neutron for decades now without success. Theorists have evolved deep understanding of the relationship between the natural forces in the development of various Grand Unified Theories (GUTs) that nearly universally predict baryon number violating proton decay, or related phenomena like n-{bar n} oscillations. With this in mind, the Proton Decay Working Group reviewed the current experimental and theoretical status of the search for baryon number violation with an eye to the advancement in the next decade.
Date: December 1994
Creator: Haines, T.; Kaneyuki, K.; McGrew, C.; Mohapatra, R.; Peterson, E. & Cline, D. B.
Partner: UNT Libraries Government Documents Department