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Proton decay theory

Description: Topics include minimal SU(5) predictions, gauge boson mediated proton decay, uncertainties in tau/sub p/, Higgs scalar effects, proton decay via Higgs scalars, supersymmetric SU(5), dimension 5 operators and proton decay, and Higgs scalars and proton decay. (WHK)
Date: January 1, 1983
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Electroweak interactions

Description: An overview of the 18 independent parameters of the standard SU(3)/sub c/ x SU(2)/sub L/ x U(1) model is given. Neutral current phenomenology and sin/sup 2/ theta/sub W/, W/sup +-/ and Z/sup 0/ masses, and testing the great desert hypothesis are discussed. The need for precise measurements in elementary particle physics is emphasized. (WHK)
Date: January 1, 1983
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Elementary particle theory

Description: The present state of the art in elementary particle theory is reviewed. Topics include quantum electrodynamics, weak interactions, electroweak unification, quantum chromodynamics, and grand unified theories. 113 references. (WHK)
Date: December 1, 1984
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Standard model and beyond

Description: The ''standard'' SU(3)/sub C/ x SU(2)/sub L/ x U(1) model of strong and electroweak interactions elegantly incorporates all the proven symmetries and successes of the quark model, quantum electrodynamics, and the Four-Fermi theory. It correctly predicted weak neutral currents as well as the existence and properties of W/sup + -/, Z and gluons. ''Only'' the predicted Higgs scalar boson remains undiscovered. At this time there are no solid experimental results that cannot be accommodated by the standard model (at the 1 or 2 sigma level). Nevertheless, we do anticipate the emergence of new physics, beyond standard model expectations, which will hopefully provide guidance for theoretical advancement. Indeed, hints of some new phenomena may already be starting to appear in the CERN anti pp collider data. Details are discussed. 65 refs.
Date: January 1, 1985
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Neutrino physics: Summary talk

Description: This paper is organized as follows: First, I describe the state of neutrino phenomenology. Emphasis is placed on sin/sup 2/ /theta//sub W/, its present status and future prospects. In addition, some signatures of ''new physics'' are described. Then, kaon physics at Fermilab is briefly discussed. I concentrate on the interesting rare decay K/sub L/ /yields/ /pi//sup 0/e/sup +/e/sup /minus// which may be a clean probe direct CP violation. Neutrino mass, mixing, and electromagnetic moments are surveyed. There, I describe the present state and future direction of accelerator based experiments. Finally, I conclude with an outlook on the future. Throughout this summary, I have drawn from and incorporated ideas discussed by other speakers at this workshop. However, I have tried to combine their ideas with my own perspective on neutrino physics and where it is headed. 49 refs., 3 figs., 4 tabs.
Date: April 1, 1989
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

KMC unitarity and K/sup +/ yields. pi. /sup +/. nu. anti. nu

Description: Experimental constraints on the Kobayashi-MaskawaCabibbo (KMC) matrix are surveyed and shown to provide a test of the standard model at the level of its O (..cap alpha..) radioactive corrections. The three generation prediction BR (K/sup +/ ..-->.. ..pi../sup +/..nu..) approx. = (0.35 approx. 3) x 10/sup 10/ is reviewed and the potential for enhancement up to approx. = 3 x 10/sup -9/ due to the fourth generation mixing is described. 19 refs.
Date: June 1, 1986
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

The standard model and beyond

Description: In these lectures, my aim is to present a status report on the standard model and some key tests of electroweak unification. Within that context, I also discuss how and where hints of new physics may emerge. To accomplish those goals, I have organized my presentation as follows. I survey the standard model parameters with particular emphasis on the gauge coupling constants and vector boson masses. Examples of new physics appendages are also commented on. In addition, I have included an appendix on dimensional regularization and a simple example which employs that technique. I focus on weak charged current phenomenology. Precision tests of the standard model are described and up-to-date values for the Cabibbo-Kobayashi-Maskawa (CKM) mixing matrix parameters are presented. Constraints implied by those tests for a 4th generation, extra Z' bosons, and compositeness are discussed. An overview of the physics of tau decays is also included. I discuss weak neutral current phenomenology and the extraction of sin/sup 2//theta/W from experiment. The results presented there are based on a global analysis of all existing data. I have chosen to concentrate that discussion on radiative corrections, the effect of a heavy top quark mass, implications for grand unified theories (GUTS), extra Z' gauge bosons, and atomic parity violation. The potential for further experimental progress is also commented on. Finally, I depart from the narrowest version of the standard model and discuss effects of neutrino masses, mixings, and electromagnetic moments. 32 refs., 3 figs., 5 tabs
Date: May 1, 1989
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Proton decay: 1982

Description: Employing the current world average ..lambda../sub MS/ = 0.160 GeV as input, the minimal Georgi-Glashow SU(5) model predicts sin/sup 2/theta/sub W/(m/sub W/) = 0.214, m/sub b//m/sub tau/ approx. = 2.8 and tau/sub p/ approx. = (0.4 approx. 12) x 10/sup 29/ yr. The first two predictions are in excellent agreement with experiment; but the implied proton lifetime is already somewhat below the present experimental bound. In this status report, uncertainties in tau/sub p/ are described and effects of appendages to the SU(5) model (such as new fermion generations, scalars, supersymmetry, etc.) are examined.
Date: March 4, 1982
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Weak neutral currents and future Z mass measurements: Anticipating SLC

Description: The goals of this work are: to test the standard SU(2)/sub L/ x U(1) model at the tree and quantum loop level, provide a precise determination of sin/sup 2/ theta/sub W/ which could, for example, be used to rule out or at least constrain various grand unified theories (GUTS), and look for hints of ''new physics.'' The topics this paper elaborates on are radiative corrections, top quark mass bounds, grand unified theories (GUTS), and extra Z' boson constraints. In addition, the implications of a precise Z boson mass determination at SLC would have when combined with existing neutral current data is examined. 21 refs., 3 figs., 3 tabs. (LSP)
Date: September 1, 1987
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Neutrino masses, mixing, moments, and matter

Description: The present status of neutrino masses, mixing, and electromagnetic moments is surveyed. Potential enhancements of neutrino oscillations, decay, and spin-flavor precession due to their interactions with matter are described.
Date: January 1, 1988
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Neutrino physics: A theoretical perspective

Description: Experimental measurements of sin/sup 2/theta/sub W/ are surveyed. They are shown to test electroweak unification at the quantum loop level and constrain new physics beyond the standard model. Neutrino oscillations are also examined in the framework of 3 generation mixing. Searches for nu/sub ..mu../ ..-->.. nu/sub tau/ oscillation at aceelerator facilities are advocated.
Date: April 1, 1987
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Electroweak radiative corrections and neutral current phenomenology

Description: Precision measurements of sin/sup 2/ theta/sub W/ including the effects of radiative corrections are surveyed. A world average sin/sup 2/ theta/sub W/ = 0.231 +- 0.004 is obtained. Comparison of deep-inelastic nu/sub ..mu../N scattering and m/sub W/ or m/sub Z/ is shown to test the standard model at the quantum loop level and constrain new physics. Implications for extra Z' bosons and grand unified theories are briefly discussed. 25 refs., 2 figs.
Date: March 1, 1987
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Electroweak interaction parameters

Description: The parameters discussed include: the renormalized weak mixing angle, masses and widths of the W plus and minus and of the Z boson, radiative Z and W boson decays. The Higgs-top quark mass connection and the Grand Unification theories are briefly reviewed. It is suggested that a new pseudoscalar particle with a mass near 93 GeV could be produced by gluon-gluon fusion. 28 references. (LEW)
Date: April 1, 1984
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Standard model parameters and the search for new physics

Description: In these lectures, my aim is to present an up-to-date status report on the standard model and some key tests of electroweak unification. Within that context, I also discuss how and where hints of new physics may emerge. To accomplish those goals, I have organized my presentation as follows: I discuss the standard model parameters with particular emphasis on the gauge coupling constants and vector boson masses. Examples of new physics appendages are also briefly commented on. In addition, because these lectures are intended for students and thus somewhat pedagogical, I have included an appendix on dimensional regularization and a simple computational example that employs that technique. Next, I focus on weak charged current phenomenology. Precision tests of the standard model are described and up-to-date values for the Cabibbo-Kobayashi-Maskawa (CKM) mixing matrix parameters are presented. Constraints implied by those tests for a 4th generation, supersymmetry, extra Z/prime/ bosons, and compositeness are also discussed. I discuss weak neutral current phenomenology and the extraction of sin/sup 2/ /theta//sub W/ from experiment. The results presented there are based on a recently completed global analysis of all existing data. I have chosen to concentrate that discussion on radiative corrections, the effect of a heavy top quark mass, and implications for grand unified theories (GUTS). The potential for further experimental progress is also commented on. I depart from the narrowest version of the standard model and discuss effects of neutrino masses and mixings. I have chosen to concentrate on oscillations, the Mikheyev-Smirnov- Wolfenstein (MSW) effect, and electromagnetic properties of neutrinos. On the latter topic, I will describe some recent work on resonant spin-flavor precession. Finally, I conclude with a prospectus on hopes for the future. 76 refs.
Date: April 1, 1988
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Proton decay theory

Description: An update is given of the gauge coupling values. The status of the original SU(5) Georgi-Glashow model predictions, which assume a great desert between m/sub W/ and m/sub X/, the unification mass scale, is described. Gauge boson mediated proton decay in the SU(5) model, and proton decay via Higgs scalars are discussed. The inclusion of supersymmetry is grand unified theories and the relation of dimension 5 operators to proton decay are discussed briefly. 14 refs. (LEW)
Date: June 1, 1986
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Charged current unitarity and extra neutral gauge bosons

Description: The experimental status of the Kobayashi-Maskawa-Cabibbo (KMC) matrix is surveyed and shown to provide a precision test of the standard model at the level of its O(..cap alpha..) radiative corrections. Implications for new physics and constraints of extra neutral gauge bosons are described. 12 refs., 1 fig.
Date: March 1, 1987
Creator: Marciano, W.J. & Sirling, A.
Partner: UNT Libraries Government Documents Department

Predicted properties of the W/sup +/,W/sup -/ and Z/sup 0/

Description: Predicted properties of the W/sup +/,W/sup -/ and Z/sup 0/ bosons in the standard SU(2) x U(1) model are presented. For the current value of the weak mixing angle, sin/sup 2/ theta/sub W/(m/sub W/) = 0.215 +- 0.014, one finds m/sub W/ = 83.0(+3.0,-2.8) GeV and m/sub Z/ = 93.8(+2.5,-2.4) GeV. Implications of deviations from these predictions are discussed. decay rates and branching ratios for the W/sup +/,W/sup -/ and Z/sup 0/ are given. Radiative corrections, higher order rare decays and exotic possibilities are described.
Date: January 1, 1982
Creator: Marciano, W.J. & Parsa, Z.
Partner: UNT Libraries Government Documents Department

The effect of extra neutral gauge bosons on neutrino-electron scattering

Description: The effects of additional neutral gauge bosons on neutrino-electron scattering cross sections are examined. Existing data are shown to provide bounds in the 100 to 250 GeV range for a class of E/sub 6/ inspired models. Estimates of the precision reachable in ongoing measurements indicates that those bounds should approach 400 GeV and a proposed new experiment at Los Alamos may probe mass scales of order 800 GeV.
Date: March 1, 1987
Creator: Godfrey, S. & Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Fermion masses and anomalous dipole moments

Description: Fermion mass generation via quantum loops is briefly described. The potential for large anomalous dipole moments, {delta}a{sub f} {approx_equal} m{sub f}{sup 2}/M{sup 2}, in such schemes is demonstrated. Implications for the muon`s anomalous magnetic moment as well as the top quark`s chromo and electroweak moments are discussed.
Date: August 1, 1995
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Radiative corrections and New Physics''

Description: Several pursuits of New Physics'' via precision measurements are surveyed. The inconsistency between tau lifetime-mass values and measured leptonic branching ratios is updated and a heavy fourth generation neutrino solution is described. Constraints on the Peskin-Takeushi S and T parameters are given. Consequences of low energy supersymmetry for grand unified theories are summarized. 15 refs., 1 tab.
Date: September 1, 1991
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Precision tests of electroweak theory

Description: Pursuits of New Physics'' via precision measurements are surveyed. The inconsistency between world average tau lifetime-mass values and measured leptonic branching ratios is updated and a heavy neutrino solution is described. The use of R{sub {tau}} {equivalent to} {Gamma}({tau} {yields} {nu}{sub {tau}} + hadrons)/{Gamma}({tau} {yields} e{bar {nu}}{sub e}{nu}{sub {tau}}) to determine {Lambda}{sub {ovr MS}} is discussed. Constraints on the Peskin-Takeuchi S and T parameters are given. Possible evidence for low energy supersymmetry from grand unified theories is scrutinized.
Date: March 1, 1992
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Tau decays: A theoretical perspective

Description: Theoretical predictions for various tau decay rates are reviewed. Effects of electroweak radiative corrections are described. Implications for precision tests of the standard model and new physics'' searches are discussed. A perspective on the tau decay puzzle and 1-prong problem is given.
Date: November 1, 1992
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Standard model status (in search of new physics'')

Description: A perspective on successes and shortcomings of the standard model is given. The complementarity between direct high energy probes of new physics and lower energy searches via precision measurements and rare reactions is described. Several illustrative examples are discussed.
Date: March 1, 1993
Creator: Marciano, W.J.
Partner: UNT Libraries Government Documents Department

Precision tests of electroweak theory

Description: Pursuits of ``New Physics`` via precision measurements are surveyed. The inconsistency between world average tau lifetime-mass values and measured leptonic branching ratios is updated and a heavy neutrino solution is described. The use of R{sub {tau}} {equivalent_to} {Gamma}({tau} {yields} {nu}{sub {tau}} + hadrons)/{Gamma}({tau} {yields} e{bar {nu}}{sub e}{nu}{sub {tau}}) to determine {Lambda}{sub {ovr MS}} is discussed. Constraints on the Peskin-Takeuchi S and T parameters are given. Possible evidence for low energy supersymmetry from grand unified theories is scrutinized.
Date: March 1, 1992
Creator: Marciano, W. J.
Partner: UNT Libraries Government Documents Department