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Tau physics at future facilities

Description: This paper dicusses and projects the tau research which may be carried out at CESR, at BEPC, at the SLC, in the next few years at LEP I, at the asymmetric B-factories under construction in Japan and the United States and, if built, a tau-charm factory. As the size of tau data sets increases, there is an increasing need to reduce the effects of systematic errors on the precision and search range of experiments. In most areas of tau physics there is a large amount of progress to be made, but in a few areas it will be difficult to substantially improve the precision of present measurements.
Date: December 1994
Creator: Perl, Martin L.
Partner: UNT Libraries Government Documents Department

Z{prime} phenomenology: Constraints from low-energy measurements, and detailed study at TeV-scale lepton and hadron colliders

Description: In this dissertation, I discuss the phenomenology of new massive neutral gauge bosons, or Z{prime} bosons, concentrating on experimental tests by which the properties of a Z{prime} boson could be determined. In Chapter I, I briefly review the Standard Model of elementary particle physics, and discuss the motivation for extending it. I review some of the extensions to the Standard Model that predict the existence of Z{prime} bosons, and present a general, model-independent parameterization of the Z{prime}s properties, as well as a simpler parameterization that applies to the most important class of models. In Chapter II, I discuss present-day limits on the existence of Z{prime} bosons, both from direct searches, and from indirect higher-order tests. In Chapter III, I discuss the production and discovery of a Z{prime} at a future hadron collider, such as the CERN Large Hadron Collider (LHC). Discovery of a Z{prime} at the LHC may be possible if its mass is less than 5 TeV. I also discuss the experimental tests of its properties that could be performed at such a collider, emphasizing the measurement of leptonic asymmetries. Finally, the Chapter IV, I discuss the experimental tests that could be performed at an e{sup +}e{sup {minus}} collider with {radical}s = M{sub Z{prime}}. I include several higher-order effects, such as initial-state radiation and beamstrahlung, whose inclusion is necesary for a realistic description of the experimental environment at a very high energy e{sup +}e{sup {minus}} collider. The combination of leptonic and hadronic experiments permits the measurement of all of the parameters.
Date: May 1, 1994
Creator: Austern, M. H.
Partner: UNT Libraries Government Documents Department

Neutron-induced charged-particle emission studies below 100 MeV at WNR

Description: Charged-particles produced by neutron bombardment of selected targets with Z=5 through 53 have been studied for neutron energies from 1 MeV to about 100 MeV using the spallation neutron source at WNR/LAMPF. Particle detection with energy measurement and particle identification is accomplished by two-element {Delta}E-E counters, three-element {Delta}E{sub l}-{Delta}E{sub 2}-E counters or with pulse-shape discrimination using scintillators directly in the neutron beam. The experimental techniques for these measurements are described and comparisons made among the different approaches. This presentation introduces five papers contributed to this conference.
Date: July 1, 1994
Creator: Haight, R. C.; Lee, T. M. & Sterbenz, S. M.
Partner: UNT Libraries Government Documents Department

Experimental consequences of supersymmetry

Description: After a brief review of the assumptions of the Minimal Supersymmetric Model (MSSM) we study the constraints on the masses of various sparticles as well as on the MSSM Higgs bosons from experiments at the Fermilab Tevatron and at LEP. We also review the range of Higgs boson masses that can be searched for at LEP 200. We then discuss the simulation of supersymmetric particle production at hadron colliders and briefly discuss event generators that we have been using in our analyses. Next, we discuss various signals that can be searched for in the present run of the Tevatron. We conclude with a study of the prospects for the detection of sparticles as well as MSSM Higgs bosons in experiments at hadron supercolliders, assuming that these are too heavy to be discovered at the Tevatron or at LEP 200.
Date: December 31, 1992
Creator: Baer, H. & Tata, X.
Partner: UNT Libraries Government Documents Department

Direct photon results from CDF

Description: Results using photons measured with the CDF detector during the 1992--93 run of the Fermilab Tevatron are presented. Photon detection and background suppression are described. Measurement of the inclusive photon cross section as well as photon-jet cross sections are discussed and compared to next-to-leading order QCD predictions. The search for excited quarks using the photon-jet mass distribution is described and a limit is derived.
Date: June 1, 1993
Creator: Flaugher, B. & Collaboration, CDF
Partner: UNT Libraries Government Documents Department

[Search for strange quark matter and antimatter produced in high energy heavy ion collisions]. Technical progress report for the period April 1990--March 1992

Description: This document describes the development and progress of our group`s research program in high energy heavy ion physics. We are a subset of the Yale experimental high energy physics effort (YAUG group) who became interested in the physics of high energy heavy ions in 1988. Our interest began with the possibility of performing significant searches for strange quark matter. As we learned more about the subject and as we gained experimental experience through our participation in AGS experiment 814, our interests have broadened. Our program has focused on the study of new particles, including (but not exclusively) strange quark matter, and the high sensitivity measurement of other composite nuclear systems such as antinuclei and various light nuclei. The importance of measurements of the known, but rare, nuclear systems lies in the study of production mechanisms. A good understanding of the physics and phenomenology of rare composite particle production in essential for the interpretation of limits to strange quark matter searches. We believe that such studies will also be useful in probing the mechanisms involved in the collision process itself. We have been involved in the running and data analysis for AGS E814. We have also worked on the R&D for AGS E864, which is an approved experiment designed to reach sensitivities where there will be a good chance of discovering strangelets or of setting significant limits on the parameters of strange quark matter.
Date: July 1, 1992
Partner: UNT Libraries Government Documents Department

Research on elementary particle physics, Task P: Studies in theory and phenomenology of elementary physics. Annual progress report, November 1, 1992--October 31, 1992: Part 1

Description: Continued progress has been made in isolating the variables needed to completely specify a quark or gluon jet, independent of the process in which it is created. We have evidence of a slow, but statistically significant, dependence on the sub-energy of the hard process in which the jet arises. Once this is taken into account, jets from e{sup +}e{sup {minus}} are consistent with those created in p{bar p}. Neural network jet identification studies win be based on this expanded set of variables. Work on the new type of Dirac equation for a relativistic oscillator was presented at the International Conference on High Energy Physics in Dallas, and will be published in the Proceedings of the Conference. Theoretical studies involving jet signals for theoretically predicted (but as yet undiscovered) particles are underway.
Date: May 1, 1993
Creator: Holloway, L. E. & O`Halloran, T. A.
Partner: UNT Libraries Government Documents Department

Measurement of tau lepton branching fractions

Description: We present {tau}{sup {minus}} lepton branching fraction measurements based on data from the TPC/Two-Gamma detector at PEP. Using a sample of{tau}{sup {minus}} {yields} {nu}{sub {tau}}K{sup {minus}}{pi}{sup +}{pi}{sup {minus}} events, we examine the resonance structure of the K{sup {minus}}{pi}{sup +}{pi}{sup {minus}} system and obtain the first measurements of branching fractions for {tau}{sup {minus}} {yields} {nu}{sub {tau}}K{sub 1}{sup {minus}}(1270) and {tau}{sup {minus}} {yields} {nu}{sub {tau}}K{sub 1}{sup {minus}}(1400). We also describe a complete set of branching fraction measurements in which all the decays of the {tau}{sup {minus}} lepton are separated into classes defined by the identities of the charged particles and an estimate of the number of neutrals. This is the first such global measurement with decay classes defined by the four possible charged particle species, e, {mu}, {pi}, and K.
Date: September 30, 1993
Creator: Nicol, N. A.
Partner: UNT Libraries Government Documents Department

A proposed search for dark-matter axions in the 0.6--16 {mu}eV range

Description: A proposed experiment is described to search for dark-matter axions in the mass range 0.6--16 {mu}eV. The method is based on the Primakoff conversion of axions into monochromatic microwave photons inside a tunable microwave cavity in a large volume high field magnet. This proposal capitalized on the availability of two Axicell magnets from the MFTF-B fusion machine at LLNL. Assuming a local dark-matter density in axions of {rho}{sub a}= 0.3 GeV/cm{sup 3}, the axion would be found or ruled out at the 97% c.1. in the above mass range in 48 months.
Date: November 1, 1991
Creator: Hagmann, C.; Moltz, D. M.; Turner, M. S.; Sikivie, P.; Sullivan, N. S.; Tanner, D. B. et al.
Partner: UNT Libraries Government Documents Department

Test beam performance of a tracking TRD (Transition Radiation Detector) prototype

Description: A Tracking Transition Radiation Detector prototype has been constructed and tested. It consists of 240 straw tubes, 4 mm in diameter, imbedded in a polyethylene block acting as the radiator. Its performance as an electron identifier as well as a tracking device for minimum ionizing particles has been determined. 2 refs., 6 figs.
Date: January 1, 1990
Creator: Shank, J.T.; Whitaker, J.S. (Boston Univ., MA (USA)); Polychronakos, V.A.; Radeka, V.; Stephani, D. (Brookhaven National Lab., Upton, NY (USA)); Beker, H. et al.
Partner: UNT Libraries Government Documents Department

SUSY searches at CDF

Description: A set of jet events with large amount of Missing E{sub Tau} from the Fermilab CDF experiment was analyses to search for SUSY signature. No significant signals were observed above the Standard Model background. Some effects of some SUSY parameters on the squark and gluino mass limits are presented.
Date: June 1, 1993
Creator: Hu, Ping & collaboration, CDF
Partner: UNT Libraries Government Documents Department

Meson production in relativistic heavy-ion collisions at AGS energies

Description: Single particle inclusive spectra are presented for pion and kaon production in Si+Au reactions at an incident momentum of 14.6 A {center_dot} GeV/c and Au+Au reactions at an incident momentum of 11.6 A {center_dot} GeV/c. A simple geometric scaling of the pion production for central collisions as A{sub proj}{sup 1/3} and A{sub targ}{sup 2/3} results from the observed production of about one pion per participant. Kaon yields are shown to be proportional to the number of excited participants and consistent with RQMD and ARC calculations.
Date: July 1, 1993
Creator: Steadman, S. G. & Collaboration, E802
Partner: UNT Libraries Government Documents Department

The status of molecules

Description: This report summarizes the experimental and theoretical status of hadronic molecules, which are weakly-bound states of two or more hadrons. We begin with a brief history of the subject and discuss a few good candidates, and then abstract some signatures for molecules which may be of interest in the classification of possible molecule states. Next we argue that a more general understanding of 2 {yields} 2 hadron-hadron scattering amplitudes will be crucial for molecule searches, and discuss some of our recent work in this area. We conclude with a discussion of a few more recent molecule candidates (notably the f{sub o}(1710)) which are not well established as molecules but satisfy some of the expected signatures.
Date: October 1, 1994
Creator: Barnes, T.
Partner: UNT Libraries Government Documents Department

Signals for top quark anomalous chromomagnetic moments at colliders

Description: The Tevatron and the Next Linear Collider (NLC) will be excellent tools for probing the detailed nature of the top quark. We perform a preliminary examination of the influence of an anomalous chromomagnetic moment for the top, {kappa}, on the characteristics of t{bar t} production at the Tevatron and on the spectrum of gluon radiation associated with t{bar t} production at the NLC. In particular, we analyze the sensitivity of future data to non-zero values of {kappa} and estimate the limits that can be placed on this parameter at the Tevatron and at the NLC with center of mass of energies of {radical}s = 500 and 1000 GeV. Constraints on {kappa} from low energy processes, such as b {yields} s{gamma} are briefly discussed.
Date: July 1, 1994
Creator: Rizzo, T. G.
Partner: UNT Libraries Government Documents Department

The DIRC counter: A new type of particle identification device for B factories

Description: A very thin, solid radiator, totally internally reflecting, imaging Cherenkov counter (DIRC) is described. this device is well matched to the hadronic charged particle identification requirements at an asymmetric e{sup +}e{sup {minus}}B Factory.
Date: July 1, 1992
Creator: Coyle, P.; Kawahara, H.; Mueller, G.; Muller, D.; Ratcliff, B.; Simopoulos, C. et al.
Partner: UNT Libraries Government Documents Department

Electron identification in the PHENIX experiment using a tracking TRD

Description: Measuring dielectron physics signals at RHIC will require the ability to separate electrons from pions to a level of better than 2 {times} 10{sup {minus}4} over momenta ranging from 0.1 GeV/c to 5.0 GeV/c. Particle identification over this momentum range is realized in the PHENIX detector at RHIC by a combination of detector subsystems, one of which is a tracking TRD. The PHENIX tracking TRD allows electron-pion separation utilizing both TR and dE/dx information, while simultaneously tracking charged particles with good position accuracy. The electron-pion separation of this device is better than 3 {times} 10{sup {minus}3} for particles with momenta ranging from 250 MeV/c to over 10 GeV/c.
Date: November 1, 1993
Creator: O`Brien, E.; Bennett, M. & Cherniatin, V.
Partner: UNT Libraries Government Documents Department

Search for top quark with D0 detector

Description: We report preliminary results of a search for the top quark by the D{O} collaboration at the Fermilab Tevatron p{bar p} collider using a data sample corresponding to an integrated luminosity of about 7.5 pb{sup {minus}1}. Events with a high p{sub T} isolated electron and large missing E{sub T} which are candidates for containing W bosons were studied. Only one vent was found having an additional isolated lepton. Combining the ee and e{mu} channels we set a lower limit of 99 GeV/c{sup 2} for the top quark mass.
Date: September 1, 1993
Creator: Protopopescu, Serban D.
Partner: UNT Libraries Government Documents Department

Recent results on top, bottom and exotic physics at the Tevatron

Description: A summary of results from the recently concluded 1991--1993 Tevatron run is presented. Selected topics from b physics and exotic particle searches from the CDF and D0 collaborations are reviewed. Preliminary results from the CDF top search, using 12pb{sup {minus}1} from the 1992--1993 run, are given. In particular, the lepton + b-tag and dilepton analyses are discussed. Preliminary results from the CDF dilepton analysis places a lower limit on the top quark mass of 108GeV/c{sup 2} at the 95% C.L.
Date: August 1, 1993
Creator: Shaw, N. M.
Partner: UNT Libraries Government Documents Department

Signal and background in NLO QCD for the search of the intermediate mass Higgs boson at the SSC

Description: The signal and background for the search of the Standard Model Higgs boson in the intermediate mass range 80 GeV < m{sub H} < 2M{sub Z} is studied based on calculations of the cross sections in next-to-leading order QCD perturbation theory for the production of the Higgs boson via gluon-gluon fusion and for the hadronic two-photon production. The method of Monte-Carlo integration allows the application of realistic cuts (p{sub T}, rapidity, photon isolation) to the cross section. Results are given for the K-factors of the signal and the background. It turns out that the NLO corrections improve the situation for a Higgs boson mass in the range of 80--120 GeV. Furthermore, the influence of a cut on the transverse momentum of the additional jet produced in the processes gg {yields} Hg, gq {yields} Hq, q{bar q} {yields} Hg is compared to a similar cut for the background.
Date: August 15, 1993
Creator: Bailey, B. & Graudenz, D.
Partner: UNT Libraries Government Documents Department

CDF top results in the lepton + jets channel

Description: Results from the 1992--1993 Tevatron run (ran IA) top search at CDF in the lepton+jets channel are reported. The jet-vertexing algorithm tags 6 events on a background of 2.3 {plus_minus} 0.3 events in the W+ {ge} 3 jets data sample, and the soft lepton analysis finds T events on a background of 3.1 {plus_minus} 0.3 events in the same data sample. Jet-vertex and soft-lepton tag correlations are described. Also given are the expected and observed number of tags in the Z+mulitjet control sample.
Date: August 1, 1994
Creator: Watts, G. & Collaboration, CDF
Partner: UNT Libraries Government Documents Department

CDF top results in the dilepton channel

Description: The current status of the top quark search at CDF in the dilepton channel is presented. In the 1992--1993 run (Run Ia), with 19.3 pb{sup {minus}1} collected, two e{mu} events survived all the cuts, including a two-jet cut for high mass top, with a total estimated background of 0.56{sub 0.13}{sup 0.25} events. With approximately 9 pb{sup {minus}1} of data analyzed from the 1993--1994 run (Run Ib) a new e{mu} event passing all the cuts has been detected.
Date: September 1994
Creator: Benlloch, Jose M.
Partner: UNT Libraries Government Documents Department

Search for excited quarks in p{bar p} collisions at {radical}s = 1.8 TeV

Description: If quarks are composite particles then excited states are expected in p{bar p} collisions. Using the CDF detector we have searched for excited quarks (q*) which decay to common quarks by emitting a W boson (q* {yields} qW) or a photon (q* {yields} q-{gamma}). In the W + jet and photon + jet mass spectra we see no compelling evidence for a q* mass resonance. We set an upper limit on the q* cross section vs. mass, and using the simplest model of excited quark production, we exclude excited quarks in the mass range 90 < M* < 570 GeV at 95% confidence level. This analysis is preliminary and only statistical uncertainties have been included.
Date: August 1, 1993
Creator: Collaboration, CDF
Partner: UNT Libraries Government Documents Department