Search

We discuss a class of models in which CP is violated softly in a heavy sector adjoined to the standard model. Heavy-sector loops produce the observed CP violation in kaon physics, yielding a tiny and probably undetectable value for $\epsilon^\prime$. All other CP-violating parameters in the effective low-energy standard model, including the area of the unitarity triangle and $\bar\theta$, are finite, calculable and can be made very small. The leading contribution to $\bar\theta$ comes from a four-loop graph. These models offer a natural realization of superweak CP violation and can resolve the strong CP puzzle. In one realization of this idea, CP is violated in the mass matrix of heavy majorana neutrinos., Comment: 12 pages, embedded figures - this version was further revised after acceptance for publication

Recent evidence for oscillations of atmospheric neutrinos at Super-Kamiokande suggest, in the simplest see-saw interpretation, neutrino masses such that `just so' vacuum oscillations can explain the solar neutrino deficit. Super-K solar neutrino data provide preliminary support for this interpretation. We describe how the just-so signal---an energy dependent seasonal variation of the event rate, might be detected within the coming years and provide general arguments constraining the sign of the variation. The expected variation at radiochemical detectors may be below present sensitivity, but a significant modulation in the $^7$Be signal could shed light on the physics of the solar core---including a direct measure of the solar core temperature., Comment: 4 pages, revtex, 4 ps figs: new refs added, and Super-K energy resolution function incorporated

We discuss the theory and phenomenology of decays of a leptophobic $U(1)_\X$ gauge boson $X$, such as has been proposed to explain the alleged deviations of $R_b$ and $R_c$ from standard model predictions. If the scalars involved in the breaking of the $SU(2)\times U(1)$ symmetry are sufficiently light, $X$ will sometimes decay into a charged (or neutral) scalar along with an oppositely-charged $W$ (or $Z$). These decay modes could yield clean signals for the leptophobic gauge bosons at hadron colliders and provide an interesting window into the Higgs sector of the theory., Comment: LATEX, 12 pages with PICTEX figures

It is shown how, in a class of models, the sign of the baryon number of the universe can be related to CP violation in neutrino oscillation experiments., 3 pages LaTeX

Recent observations of solar neutrinos along with decades of data from the chlorine experiment seem to be converging on an explanation of the sun's neutrino deficit. Electron and muon neutrinos with Majorana masses ∼10-3 eV/c2 are subject to MSW suppression as they traverse the sun. However, Simpson's studies of s-decay spectra show that νe mixes with a Dirac neutrino (presumably ντ) of a consmologically nettlesome mass. We propose a simple modification of the singlet majoron hypothesis that accounts for these results yet remains in accord with known constraints from particle physics and cosmological theory. Maximal ντ oscillations into a sterile state are predicted.

Recent data lead us to a simple and intriguing form of the neutrino mass matrix. In particular, we find solar neutrino oscillations to be nearly maximal (and rule out the small-angle MSW explanation of solar neutrino observations) if relic neutrinos comprise at least one~percent of the critical mass density of the universe., Comment: 7 pages, harvmac, minor changes and new references in revised version

Radioactive decays inside the Earth produce antineutrinos that may be detectable at the surface. Their flux and spectrum contain important geophysical information. New detectors need to be developed, discriminating between sources of antineutrinos, including the cosmic-background. The latter can be related to the frequency of supernovas.

We estimate the cross section for Higgs-boson production in proton-proton collisions. We find that most of the cross section comes from a two-gluon annihilation process, in which the gluons couple to Higgs bosons via heavy-quark loops.

We point out that the assumption of Lorentz noninvariance examined recently by Coleman and Glashow leads to neutrino flavor oscillations which are phenomenologically equivalent to those obtained by assuming the neutrinos violate the principle of equivalence. We then comment on the limits on Lorentz noninvariance which can be derived from solar, atmospheric, and accelerator neutrino experiments.

We examine certain extensions of the standard model in which $\mathrm{CP}$ violation is spontaneous and the strong $\mathrm{CP}$ problem is resolved. In these models, the $3\ifmmode\times\else\texttimes\fi{}3$ quark-mixing matrix is neither real nor unitary. However, to a precision of 0.1%, it is real and orthogonal. There are no readily observable $\mathrm{CP}$-violating effects other than those in the neutral kaon system.

We constrain our previous double-{ital Z} model using available data. We show that it cannot lead to new physics in present or near-future experiments. We consider herein only {ital Z}{prime}-related phenomena, mainly low-energy induced interactions and modifications at the {ital Z} peak but also {ital p{bar p}} scattering measured by the Collider Detector at Fermilab and the forward-backward (or charge) lepton asymmetry in electron-positron annihilation.

This paper reviews the success of the quark model in describing deep-inelastic lepton scattering. The neutral current predictions of a variety of unified gauge models are given and it is shown how experiment may distinguish among them. All the models involve new hadronic quantum numbers (charm or fancy). Their effects at high energy are explored.

A singlet majoron model is invoked to generate unstable neutrinos with masses comparable to present direct limits. The tau-neutrino is predicted to be short-lived, neutrino-counting experiments can yield non-integer results, unusual decay modes of W and Z are anticipated, and there can be no cosmic flux of muon-neutrinos.

We propose as an addition to the conventional charm-changing charged current the $V+A$ current ${\overline{\mathcal{P}}}^{\ensuremath{'}}{\ensuremath{\gamma}}_{\ensuremath{\mu}}(1\ensuremath{-}{\ensuremath{\gamma}}_{5})\mathfrak{N}$. It explains the observed enhancement of nonleptonic $\ensuremath{\Delta}I=\frac{1}{2}$ weak decays, allows low-lying charmed hadrons to decay comparably into strange and non-strange final states, predicts the appearance of ${\ensuremath{\mu}}^{\ensuremath{-}}{l}^{\ensuremath{-}}$ (as well as ${\ensuremath{\mu}}^{\ensuremath{-}}{l}^{+}$) dilepton events in neutrino interactions, and leads to copious quasielastic charm production by neutrinos.

Recent data compel us to interpret several peaks in the cross section of ${e}^{\ensuremath{-}}{e}^{+}$ annihilation into hadrons as being due to the production of four-quark molecules, i.e., resonances between two charmed mesons. A rich spectroscopy of such states is predicted and may be studied in ${e}^{\ensuremath{-}}{e}^{+}$ annihilation.

In July of 1983, the High Energy Physics Advisory Panel of the Department of Energy recommended that the highest priority be given to construction of a very large accelerator, the Superconducting Super Collider. The recommended energy per beam of this accelerator is 20 TeV, or 20 000 GeV—this is a macroscopic energy of about 32 ergs for each proton in the beam. Head‐on collisions of protons against protons will thus make 40 TeV available in the center of mass, more than 60 times the energy available at the present CERN collider and 20 times that to become available at the Fermi National Accelerator Laboratory in the near future. The committee urged, moreover, that this facility be completed and available for physics research within about a decade. The solemnity of the advice was underscored by the simultaneous recommendations that all other proposals for high‐energy accelerators not be approved. This included both the Colliding Beam Accelerator, in which the Brookhaven National Laboratory had invested con...

We explore the consequences of the assumption that the direct and induced weak neutral currents in an $\mathrm{SU}(2)\ensuremath{\bigotimes}\mathrm{U}(1)$ gauge theory conserve all quark flavors naturally, i.e., for all values of the parameters of the theory. This requires that all quarks of a given charge and helicity must have the same values of weak ${T}_{3}$ and ${\stackrel{\ensuremath{\rightarrow}}{T}}^{2}$. If all quarks have charge +2/3 or -1/3 the only acceptable theories are the "standard" and "pure vector" models, or their generalizations to six or more quarks. In addition, there are severe constraints on the couplings of Higgs bosons, which apparently cannot be satisfied in pure vector models. We also consider the possibility that neutral currents conserve strangeness but not charm. A natural seven-quark model of this sort is described. The experimental consequences of charm nonconservation in direct or induced neutral currents are found to be quite dramatic.

We examine in detail the possibility that the low rates observed in the chlorine solar neutrino experiment are due to vacuum oscillations between just two neutrino species — a possibility which remains viable over a finite mass range. We calculate the expected signals, seasonal variations, and effects of time-averaging for both chlorine and gallium based solar neutrino detectors. These provide unique signals for such oscillations, and thus also allow them to be distinguished from the recently proposed resonant neutrino conversion process, as well as from other possible causes of the observed suppression. Finally we display several striking signatures of oscillations relevant to future experiments which may be sensitive to the incident neutrino energy spectrum.

E. Witten (personal communication) has raised the intriguing possibility that nuclear matter consisting of aggregates of up, down and strange quarks in roughly equal proportions may be less massive than ordinary nuclear matter of the same quark number consisting of protons and neutrons (triplets of non-strange quarks). These nuggets of strange quark matter may be stable for almost any baryon number (A), including values intermediate between those of ordinary nuclei (A≲263) and neutron stars (A ∼ 1057). We use the term ‘nuclearite’ to describe such strange quark nuggets in collision with Earth and suggest experiments to detect these encounters.

We explore the implications for hadron spectroscopy of the "standard" gauge model of weak, electromagnetic, and strong interactions. The model involves four types of fractionally charged quarks, each in three colors, coupling to massless gauge gluons. The quarks are confined within colorless hadrons by a long-range spin-independent force realizing infrared slavery. We use the asymptotic freedom of the model to argue that for the calculation of hadron masses, the short-range quark-quark interaction may be taken to be Coulomb-like. We rederive many successful quark-model mass relations for the low-lying hadrons. Because a specific interaction and symmetry-breaking mechanism are forced on us by the underlying renormalizable gauge field theory, we also obtain new mass relations. They are well satisfied. We develop a qualitative understanding of many features of the hadron mass spectrum, such as the origin and sign of the $\ensuremath{\Sigma}\ensuremath{-}\ensuremath{\Lambda}$ mass splitting. Interpreting the newly discovered narrow boson resonances as states of charmonium, we use the model to predict the masses of charmed mesons and baryons.

A class of theories of electroweak and strong interactions which do not involve at quark is just as attractive as the conventional theory which does. Direct observation of b quark decay will distinguish between these two possibilities, as, of course, would observations of the t.

Recently reported observations suggest the existence of a new particle without strong interactions. We interpret it as a massive neutral lepton ${L}^{0}$ produced by decays of a new charged lepton ${L}^{\ifmmode\pm\else\textpm\fi{}}$ which in turn is pair-produced electromagnetically by cosmic rays. The mass of ${L}^{\ifmmode\pm\else\textpm\fi{}}$ must be \ensuremath{\sim}2 GeV; the lifetime of ${L}^{0}$ must be \ensuremath{\sim} ${10}^{\ensuremath{-}5}$ sec. Possible gauge models incorporating the new leptons are discussed, as are other experimental consequences.

We investigate the origin of the Cabibbo angle and other flavor-mixing angles in an ambidextrous SU(2)L × SU(2)R × U(1) gauge theory of weak and electromagnetic interactions involving 2n quark flavors. We show how a discrete symmetry of the Lagrangian leads to flavor-diagonal weak currents where all flavor-mixing angles vanish. Each quark is assigned a position on the “clock of flavor” and the charged-current weak interactions are identified as nearest-flavor couplings. Soft breakdown of the discrete symmetry leads to a one-parameter family of flavor-mixing angles in the charged weak currents. All angles are expressed in terms of this parameter and quark mass ratios. The neutral currents remain flavor diagonal. Upper and lower bounds on 2n, the number of flavors, are obtained by constraining the theory to fit what is known from experiment. Departures from Cabibbo universality become intolerable if 2n 12. We conclude that the number of flavors must be 8, 10, or 12. We construct a more ambitious theory in which the Cabibbo angle and its analogs are O(α) calculable radiative corrections. For reasonable values of the quark mass ratios, we fail to obtain a Cabibbo angle of the right order of magnitude. Our theory involves an equal number of lepton flavors and quark flavors. A large number of flavors is required if neutrinos are to be sufficiently light. We explore the case of 2n = 12, and find a novel mechanism for the neutrino induction of trimuon events.

The three kinds of quarks, arbitrarily assigned different flavors and colors, are discussed in relation to the structure of particles. (JFP)

Radioactive decays inside the Earth produce antineutrinos that may be detectable at the surface. Their flux and spectrum contain important geophysical information. New detectors need to be developed, discriminating between sources of antineutrinos, including the cosmic-background. The latter can be related to the frequency of supernovas.

A massive charged scalar, such as is present in a two Higgs-doublet electroweak theory, can alter the nature of top-quark decay, ensuring that the top quark would not have been detected at hadron colliders. Box diagrams involving charged-scalar exchange can produce the observed level of B0− B 0 mixing, thus relaxing the need for a heavy top quark. Future experiments can readily establish the existence of the charged scalar.

Quantum chromodynamics may be a relic of the spontaneous breakdown of a larger gauge group just as QED survives the spontaneous breakdown of electroweak SU(2)×U(1). We speculate that QCD originates in the chiral color group SU(3)×SU(3), and that the scale of chiral-color breaking is similar to the electroweak mass scale. Such theories predict the existence of many new fundamental particles including especially the “axigluon”. This spin-one massive gauge particle should weigh several hundred GeV and be visible as a jet-jet resonance at hadron colliders.

We compute the cross section for the process e + e − →Hff as a function of Higgs boson mass and of center-of-mass energies of M z and beyond. We conclude that searches for a Higgs of mass less than 50 GeV are far more effective when carried out near the Z boson resonance that at any higher energy. However, a new window of Higgs boson masses extending from 50–107 GeV can be explored if and when e + e − collisions can be studied with high luminosity at collision energies of 200 GeV. Collider energies at intermediate energies can play no useful role in the search for the Higgs.

We estimate the cross section for charmed particle production in proton-proton scattering. An analysis of all possible sources of charmed particles reveals that the dominant mechanism at high energy involves the annihilation of constituent gluon partons. This process is as effective as the annihilation of constituent quark and antiquark partons in proton-antiproton scattering. Our unorthodox conclusion is that proton-proton collisions are practically as effective as proton-antiproton collisions for the production of charmed particles, or for the production of states involving heavier quarks. Gluon-gluon collisions may also produce light quark pairs. The possible relation between this process and the observed rising pp total cross section is discussed.

We search for a renormalizable gauge theory incorporating our modified weak current. The right-handed quarks participate to give a natural explanation for the nonleptonic $\ensuremath{\Delta}I=\frac{1}{2}$ rule. We argue that extra quarks and/or extra leptons are necessary. We focus on a vector-like model involving six different quark "flavors," each in a color triplet: 18 quarks all told. The model also involves a third charged lepton and several massive neutral leptons. We compare the predictions of our model with the conventional (12 quarks) model. Present experimental data are insufficient to discriminate between the two models. We give detailed analyses and predictions concerning charged-current and neutral-current phenomena, including inclusive scattering, scattering of neutrinos by electrons, single-pion production, and neutrino or antineutrino elastic scattering on protons.

Unification of strong and electroweak forces implies that protons (and bound neutrons) decay. Modes like $\overline{\ensuremath{\nu}}\ensuremath{\pi}$, ${e}^{+}\ensuremath{\pi}$, and ${\ensuremath{\mu}}^{+}{K}^{0}$ are expected, while modes like ${\ensuremath{\mu}}^{+}\ensuremath{\pi}$ and ${e}^{+}{K}^{0}$ are "Cabibbo" suppressed. Branching ratios can reveal much about the nature of the unifying group and the origin of fermion masses. Plausible models of unification and flavor mixing give surprisingly different predictions for two-body branching ratios.

The Linde-Weinberg bound [1] on the mass of the Higgs boson does not apply if one of the fermions of the standard model is very massive [2] or in non-standard models with multiple Higgs particles [1]. We consider both the standard model and a common extension thereof to two or more Higgs doublets. If the Higgs responsible for lepton masses is very light, one reliable method for indirectly detecting it would be a more careful measurement of g − 2 for the muon. More direct is the search for Higgs particles detected in association with τ pairs in existing or defunct e+e− colliders operating well below the Z mass. We analyze both methods in detail, and find that data from several existing colliders could eliminate large portions of parameter space - or, perhaps, find the Higgs boson.

Electron-positron annihilation should be a rich source of charmed hadrons. The search for invariant-mass peaks together with the measurement of recoil-mass spectra is a technique that recently has borne fruit at SPEAR. We show how this technique may reveal the existence of the charmed baryons and of the excited states of the charmed mesons.

We present an alternative to the Cabibbo theory in the context of a renormalizable gauge model of weak and electromagnetic interactions. The strangeness-changing hadronic weak current is assumed to be V+A.

The model of Czyz, Ericson and Glashow for multiple meson production in energetic nucleon-nucleon collisions is applied to the analogous pion-nucleon process. The angular distributions of the shower particles of such events are predicted to display a single-cone structure, and to be forward peaked in the centre-of-mass system at primary energies greater than 400 GeV. The model should be applicable for pion energies beyond 50 GeV.

The nonleptonic decay amplitudes of the $K$ mesons are calculated using current algebra and the spectral-function sum rules. The result is convergent in the intermediate-boson model, but not for a direct current-current interaction. Comparison with the observed rate for ${{K}_{1}}^{0}$ decay shows that the intermediate-boson mass is about 8 BeV.

It was shown that the partial widths for the various twobody decay modes of the gamma octet and of the delta decuplet were compatible with unitary symmetry of strong interactions. The experimental partial widths for decay into meson plus baryon were summarized. Two of these were used as input variables determining the eightfold-way D and F decay coupling-constants for the gamma octet; the remaining five partial widths were calculated after adjustment of a radius of interaction. The calculation was repeated for the delta decuplet. Agreement with experiment was found. (C.E.S.)

We propose a model of weak interactions in which the currents are constructed out of four basic quark fields and interact with a charged massive vector boson. We show, to all orders in perturbation theory, that the leading divergences do not violate any strong-interaction symmetry and the next to the leading divergences respect all observed weak-interaction selection rules. The model features a remarkable symmetry between leptons and quarks. The extension of our model to a complete Yang-Mills theory is discussed.

A new and less restrictive criterion is deduced for the renormalizability of vector meson interactions. As an example, the electromagnetic interaction of a charged vector meson with unit anomalous magnetic moment is shown to be renormalizable. In order to construct a renormalizable theory of the elementary-particle decays in which such a particle plays the role of an intermediary, it is found necessary to assume an intimate connection between decay-inducing and electrodynamic interactions.

Weak and electromagnetic interactions of the leptons are examined under the hypothesis that the weak interactions are mediated by vector bosons. With only an isotopic triplet of leptons coupled to a triplet of vector bosons (two charged decay-intermediaries and the photon) the theory possesses no partial-symmetries. Such symmetries may be established if additional vector bosons or additional leptons are introduced. Since the latter possibility yields a theory disagreeing with experiment, the simplest partially-symmetric model reproducing the observed electromagnetic and weak interactions of leptons requires the existence of at least four vector-boson fields (including the photon). Corresponding partially-conserved quantities suggest leptonic analogues to the conserved quantities associated with strong interactions: strangeness and isobaric spin.

The up-down asymmetry of atmospheric neutrinos resulting from neutrino oscillations is studied.

We compute the decay rate of Z 0 into gluon plus axigluon in the chiral color model. Results are plotted as a function of axigluon mass for various choices of unknown fermion masses.

The ζ (8.3 GeV) is interpreted as the lighter of two Higgs bosons. Experiments are suggested to confirm this hypothesis.

Slowly moving massive neutrinos may be responsible for the invisible mass in galactic halos and the missing mass of the universe. Massive neutrinos are expected to decay into lighter neutrinos and uv photons, with lifetimes long on the Hubble scale. The possible detection of these neutrino-decay photons is discussed.

We estimate the cross section for Higgs-boson production in proton-proton collisions. We find that most of the cross section comes from a two-gluon annihilation process, in which the gluons couple to Higgs bosons via heavy-quark loops.

We describe certain novel leptonic processes suggested by the ambidextrous model of weak interactions. Heavy charged leptons are occasionally produced by neutrinos or antineutrinos. They can decay via right-handed current-current couplings into a muon, a massive neutral lepton, and its antiparticle. Subsequent decay of the heavy neutrals yields from three to five final-state leptons. Same-sign (or ''symmetric'' opposite-sign) dimuon events are produced by an alternative decay mode of the heavy charged leptons.

Isospin-violating electromagnetic contributions to the decays J/psi..-->..baryon+antibaryon are examined. We find that these isospin-violating effects may be large, and that they depend sensitively on the magnetic form factors of the baryons.

Arguments are presented suggesting that the top-quark analog of the J/psi should lie at 38 +- 2 GeV. Should there exist a fourth Q=2/3 quark h, the first h-barh state must be heavier than 300 GeV.

The use of Han-Nambu quarks enables us to construct an SO(3) gauge theory of weak and electromagnetic interactions which is compatible with the naive quark model. The model is constrained by the requirements that ${K}_{L}\ensuremath{\rightarrow}\ensuremath{\mu}\overline{\ensuremath{\mu}}$ is suppressed and the ${K}_{L}\ensuremath{-}{K}_{S}$ mass splitting is small. This leads to a relation between the $W$ mass and the Cabibbo angle, which determines the $W$ mass to be near 35 GeV.

In the past twenty years, the great accelerators have dominated the field of high-energy physics. Consider the 16 basic particles of contemporary physics: six leptons, photons, gluons, W’s and Z’s. Seven of them were “discovered” before 1960 without the use of artificial acceleration. Five were discovered since 1960 and with accelerators. Brookhaven may claim muon neutrinos and part of charm; SPEAR found the tau lepton and the rest of charm; Fermilab found beauty; and PETRA saw the spoor of gluons. Four fundamental particles remain: the tau neutrino, the top quark, and the two weak-interaction intermediaries. These particles will almost certainly turn up at accelerators during the eighties. It seems folly to speak now of the end of the high-energy frontier. So much is to be done, and so many machines are abuilding.