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Topcolor

Description: We review a class of dynamical models in which top condensation occurs at the weak scale, giving rise to the large top quark mass and other phenomena. This typically requires a color embedding, SU(3){sub c} {yields} SU(3){sub 1} x SU(3){sub 2}, ergo ``Topcolor.`` Topcolor suggests a novel route to technicolor models in which sequential quarks condense under the Topcolor interaction to break electroweak symmetries.
Date: November 1, 1996
Partner: UNT Libraries Government Documents Department

Non-SUSY exotic particle searches at the Tevatron

Description: Between 1992 and 1995, the CDF and D0 collaborations collected data from p{anti p} collisions at {radical}s = 1.8 TeV. Recently, several analyses of this data have been performed in search of evidence for various non-Supersymmetric exotic particles. As no evidence for the existence of these particles is observed, confidence level limits are established for exotic particle predictions from various theoretical models. Analyses presented here include searches for Standard Model Higgs, technicolor particles, topcolor-assissted technicolor bosons, and flavor-universal colorons.
Date: June 29, 1999
Creator: Cassada, J.
Partner: UNT Libraries Government Documents Department

Color and experimental physics

Description: After a brief review of the color hypothesis and the motivations for its introduction, the experimental tests arare discussed. It is assumed that colored states have not been produced at present energies and only experimental tests which apply below the color threshold, when color is a ''hidden symmetry,'' are discussed. Some of these tests offer the possibility of distinguishing between quark models with fractional and integral quark charges. (auth)
Date: August 20, 1975
Creator: Chanowitz, M.S.
Partner: UNT Libraries Government Documents Department

Summary of recent color coherence results

Description: Recent experimental results on color coherence phenomena from e{sup +}e{sup -}, ep, and p{anti p} collisions are presented. The data are compared to analytic perturbative QCD calculations based on the modified leading logarithm approximation and the local parton hadron duality hypothesis.
Date: August 1, 1998
Creator: Varelas, N., University of Chicago
Partner: UNT Libraries Government Documents Department

Color coherence in p{bar p} collisions at {radical}s = 1.8 TeV

Description: We report on two preliminary studies of color coherence effects in pp collisions based on data collected by the D{O} detector during the 1992-1993 and 1994-1995 runs of the Fermilab Tevatron collider at a center of mass energy {radical}s = 1.8 TeV. Demonstration of initial-to-final state color interference effects is done in a higher energy region by measuring spatial correlations between the softer third jet and the second leading-ET jet in multi-jet events and in a lower energy regime by examining particle distribution patterns in W+Jet events. The data are compared to Monte Carlo simulations with different color coherence implementations and to the predictions of a NLO parton-level calculation.
Date: September 1, 1996
Creator: Cullen-Vidal, D.E.
Partner: UNT Libraries Government Documents Department

Testing technicolor with scalars at the first muon collider

Description: An interesting class of models of dynamical electroweak symmetry breaking allows only the third generation fermions to acquire dynamical masses, such that the masses of the first two generations should be given by coupling to a nonstandard ``Higgs`` doublet. The scalars in this case have large couplings to the second generation, so that they are copiously produced at a muon collider. We analyze the potential for discovery of the neutral scalars in the s-channel, and we show that at resonance there will be observed in excess of 10{sup 5} events per year.
Date: February 1, 1998
Creator: Dobrescu, B.A.
Partner: UNT Libraries Government Documents Department

Color coherence in W + jet events

Description: We report on preliminary studies of color coherence effects in p{anti p} collisions, based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron collider, at a center of mass energy {radical}s = 1.8 TeV. Color interference effects are studied by examining particle distribution patterns in W + Jet events. The data are compared to Monte Carlo simulations with different color coherence implementations and to a recent analytic Modified-Leading-Log perturbative calculation based on the Local Parton-Hadron Duality hypothesis. Soft particle radiation is enhanced in the event plane relative to the transverse plane, in agreement with calculations in which the effects of color coherence are fully included.
Date: November 1, 1997
Creator: Abbott, B.
Partner: UNT Libraries Government Documents Department

Onium and b production at the Tevatron

Description: Recent data from the CDF and D0 experiments at the Tevatron are presented on b quark production cross sections, J/{psi}, {psi}{prime} and {Upsilon} production cross sections. An analysis from CDF of the production polarization of the J/{psi}, {psi}{prime} and {Upsilon}(1S) is reviewed and the results discussed in the context of the color octet model.
Date: January 27, 2000
Creator: Sumorok, K.
Partner: UNT Libraries Government Documents Department

Recent B physics results at CDF

Description: Three recent B physics results at CDF are presented. The first analysis measures the production polarization of the {psi}(2S) from its decay into {mu}<sup>+</sup>{mu}<sup>-</sup>. The second one determines the {chi}<sub>b</sub> contribution to the {Upsilon}(1S) production. Both analyses are important tests of the Color Octet Model. The third analysis related here is a measurement of the full decay amplitudes of B<sup>0</sup> {yields} J/{psi}K<sup>*0</sup> and B<sup>0</sup><sub>s</sub> {yields} J/{psi}{phi}. This provides both a test of the factorization model and information relevant to CP violation studies in the B sector. All of the results are to be considered preliminary.
Date: July 26, 1999
Creator: Ribon, A.
Partner: UNT Libraries Government Documents Department

Unresolved questions in J/{psi} production and propagation in nuclei

Description: In order to understand the J/{psi} suppression arising from the possible occurrence of the quark-gluon plasma in high-energy heavy-ion collisions, it is necessary to have a comprehensive picture how the J/{psi} and its precursors are produced, what their properties after production are, and how the J/{psi} and its precursors propagate inside nuclear matter. There are unresolved questions in the descriptions of J/{psi} production and propagation. The author outlines some of these questions and discusses the approaches for their resolution.
Date: November 1, 1998
Creator: Wong, C.Y.
Partner: UNT Libraries Government Documents Department

Strongly-interacting color-singlet exchange in {anti p}-p collisions at {radical}s = 1800 GeV

Description: Results are presented from an analysis of the particle multiplicity between high transverse energy jets in {anti p}-p collisions at {radical}s = 1,800 GeV. The data were collected using the D0 Detector at Fermi National Accelerator Laboratory. The authors observe an excess of events at low multiplicity which is consistent with strongly interacting color-singlet exchange. The fraction of events due to color-singlet exchange is measured as a function of the transverse energy and rapidity separation of the jets and is compared to several theoretical models for color-singlet exchange.
Date: December 1, 1997
Creator: Thomas, T.L.T.
Partner: UNT Libraries Government Documents Department

Summary of the parallel session on hadron dynamics

Description: The hadron dynamics sessions focussed on A-dependent effects in hard interactions and heavy quark production, as well as color transparency effects. Other topics covered included exclusive processes and spin effects.
Date: December 31, 1994
Creator: Corcoran, M.D. & Carroll, A.S.
Partner: UNT Libraries Government Documents Department

Searches for large extra dimensions and technicolor at the Tevatron

Description: The authors presents the status of searches for large extra spacetime dimensions and technicolor at the Fermilab Tevatron. The author emphasizes recent D0 limits on graviton-mediated exchange processes, and CDF searches for new b{anti b} resonances and third-generation leptoquarks.
Date: August 1, 2000
Creator: Gerdes, David
Partner: UNT Libraries Government Documents Department

Color coherent radiation in multijet events from p{bar p} collisions at {radical}s = 1.8 TeV

Description: We report on a study of color coherence effects in p{bar p} collisions based on data collected by the D0 detector during the 1992-1993 run of the Fermilab Tevatron collider at the center of mass energy {radical}s = 1.8 TeV. We demonstrate initial-to-final state color interference effects by measuring spatial correlations between soft and hard jets in multijet events. The data are compared to Monte Carlo simulations with different color coherence implementations and to the predictions of a NLO parton level calculation.
Date: August 1, 1995
Creator: Abachi, S.; Ahn, S. & Baldin, B.
Partner: UNT Libraries Government Documents Department

Theoretical studies in high energy nuclear physics. Progress report

Description: This paper is a progress report for the period 1-1-93 to 6-30-95 on a project primarily directed at the application of high energy physics techniques to nuclear structure studies, and the ability to study hadron dynamics through interactions with nuclear targets. This work has included the first legitimate QCD calculations of hard coherent diffractive processes off nucleon (nuclear) targets which established novel features of color transparency phenomenon not anticipated in the previous intuitive or QCD inspired model calculations and predicted the fast increase of the cross section for electroproduction of {rho}-mesons with increase of the energy, which was confirmed very recently by the first HERA data on this reaction. First theoretical demonstration that color transparency phenomenon for the hard diffractive processes follow from QCD in the kinematics when both x{yields}0 and Q{sup 2}{yields}{infinity}. Establishing the pattern of color (cross section) fluctuations in hadrons. Confirmed by the FNAL inelastic diffraction data. Finding that in realistic quark, skyrmion models of a hadron large momentum transfer elastic lepton-hadron scattering occurs through formation of small spatial size configurations. Discovering a novel class of color transparency sensitive double interaction processes which is complementary to quasielastic reactions originally suggested by S. Brodsky and A. Mueller. Adopting ideas suggested elsewhere for hadron initiated reactions they developed a method for taking into account nuclear correlations in (e,e{prime}p) reactions. Such an approach gives practical possibility to overcome ambiguities of optical model approximation used before and to reliably interpret color transparency effects at intermediate Q{sup 2}.
Date: August 1, 1995
Partner: UNT Libraries Government Documents Department

Theoretical nuclear reaction and structure studies using hyperons and photons. Final report

Description: This report details research progress and results obtained during the ten period from June 1, 1988 through May 31, 1998. In compliance with grant requirements the Principal Investigator, Professor Stephen R. Cotanch, has conducted a research program addressing theoretical investigations of reactions involving hyperons and photons. The Principal Investigator has devoted to this program 50% of his time during the academic year and 100% of this time in the summer. Highlights of significant research results are briefly summarized in this report which respectively correspond to the three sub-programs of this project.
Date: December 31, 1998
Creator: Cotanch, S. R.
Partner: UNT Libraries Government Documents Department

Color coherence in p pbar collisions at squareroot s = 1.8 TeV

Description: We report on two preliminary studies of color coherence effects on {ital p}{ital {anti p}} collisions based on data collected by the D{null} detector during the 1992-1993 and 1994-1995 runs at the Fermilab Tevatron collider at a center of mass energy {radical}s = 1. 8 TeV. Demonstration of initial-to-final state color interference effects is done in a higher energy region by measuring spatial correlations between the softer third jet and the second leading- {ital E}{sub {ital T}} jet in multi-jet events and in a lower energy regime by examining particle distribution patterns in W+Jet events. The data are compared to Monte Carlo simulations with different color coherence implementations and the predictions of an NLO parton level calculation.
Date: September 1, 1996
Creator: Abachi, S.
Partner: UNT Libraries Government Documents Department

Effects of final-state interaction and screening on strange and heavy quark production

Description: Final-state interaction and screening have a great influence on {ital q{anti q}} production cross sections, which are important quantities in many problems in quark-gluon plasma physics. They lead to an enhancement of the cross section for a {ital q{anti q}} color-singlet state and a suppression for a color-octet state. The effects are large near the production threshold. The presence of screening gives rise to resonances for {ital q{anti q}} production just above the threshold at specific plasma temperatures. These resonances, especially {ital c{anti c}} and {ital b{anti b}} resonances, may be utilized to search for the quark-gluon plasma by studying the temperature dependence of heavy-quark pair production just above the threshold.
Date: October 1, 1996
Creator: Wong, Cheuk-Yin & Chatterjee, L.
Partner: UNT Libraries Government Documents Department

Discovery mass reach for topgluons decaying to t{bar t} at the Tevatron

Description: In topcolor assisted technicolor, topgluons are massive gluons which couple mainly to top and bottom quarks. We estimate the mass reach for topgluons decaying to {ital t{anti t}} at the Tevatron as a function of integrated luminosity. The mass reach for topgluons decreases with increasing topgluon width, and is 1.0 - 1.1 TeV for Run H (2 fb{sup - 1}) and 1.3 - 1.4 TeV for TeV33 (30 fb{sup -1}).
Date: September 1, 1996
Creator: Harris, R.M.
Partner: UNT Libraries Government Documents Department

Jet studies at all rapidities from D0 and CDF

Description: We present results on measurements of jet shapes, color coherence, and topology of multijet events from {ital p}{ital {anti p}} collisions at {radical}s = TeV at the Fermilab Tevatron collider using the CDF and D{null} detectors. The data are compared to next-to-leading order QCD calculations, or to predictions of parton shower based Monte Carlo models.
Date: August 1, 1996
Creator: Varelas, N. & Collaborations, D0 and CDF
Partner: UNT Libraries Government Documents Department

Leptoquark searches at the Tevatron

Description: The authors report on searches for leptoquarks using approximately 100 pb {sup -1} of data collected by CDF and DO during Run I at the Tevatron. They also present searches for resonantly-produced leptoquarks that arise in technicolor models. Prospects for future leptoquark searches using Run II data are also discussed.
Date: June 23, 2000
Creator: Acosta, Darin E.
Partner: UNT Libraries Government Documents Department