Weak Intermediate Bosons Research Articles

On the Weak Intermediate Boson

On the Weak Intermediate Boson

Anomalous structure of weak intermediate bosons.

The unpolarized and polarized quark and gluon content of the weak intermediate bosons of the standard model is investigated at an energy scale much higher than their masses. The evolution equations for polarized quark and gluon densities are constructed and solved asymptotically. The structure of the Z and W bosons turns out to be much richer than that of the photon. Strong flavor and spin dependence is observed.

Structure functions of W and Z bosons

The strong content of the weak intermediate bosons is investigated at energies much higher than their masses. The evolution equations of quark and gluon densities are constructed and solved asymptotically. Strong flavour and spin dependence is observed. The special role of longitudinally polarized bosons is discussed.

Weak-boson production by charm quarks.

We propose a method to extract the charm structure function of the nucleon $c(x,{Q}^{2}={m}_{W}^{2})$ from measurements of the rapidity distribution of ${W}^{\ifmmode\pm\else\textpm\fi{}}$ and $Z$ in $p\overline{p}$ collisions. The production of weak intermediate bosons via charm occurs at the few percent level at the Fermilab Tevatron and has in particular a strong influence on the important measurements of the ratio of $W$ and $Z$ events as $c\overline{s}\ensuremath{\rightarrow}W$ is expected to be much larger than $c\overline{c}\ensuremath{\rightarrow}Z$.

Are weak vector bosons composite?

Recentcern \(p\bar p\) collider data on anomalousZ° events suggest, among other possibilities, a composite structure for the weak intermediate vector bosons. We present a short review of these developments and examine how far the scenario for weak interactions with such composite models of the weak vector bosons presents a viable alternative to the standard electroweak theory. In particular, we show how the scale of the dynamics underlying the composite structure is set by the magnitude of the weak mixing angle sin2 θ w and point out the possibility of accommodating the anomalous\(Z^ \circ - l\tilde l\gamma \) decay events presently observed within this picture.

Weak bosons as composite gauge fields of hidden symmetries

We find a hidden local symmetry in the supersymmetric U(4 n f +2)/ U(4 n f )× SU(2) non-linear sigma model which was proposed recently as a phenomelogical model coming from the SU(2) preon theory. The hidden symmetry is identifiable with the standard electro-weak SU(2) L gauge symmetry and thus we suggest that the weak intermediate bosons discovered at CERN may be dynamical gauge fields of the hidden symmetry.

Cosmic-ray-neutrino tests for heavier weak bosons and cosmic antimatter

We present a broad program for using high-energy neutrino astronomy with large neutrino detectors to directly test for the existence of heavier weak intermediate vector bosons (IVB's) and cosmic antimatter. Changes in the total cross section for ..nu..N..--> mu..X due to additional propagators are discussed and higher-mass resonances in the annihilation channel nu-bar/sub e/e/sup -/..-->..X are analyzed. The annihilation channel is instrumental in the search for antimatter, particularly if heavier IVB's exist.

The substructure of the weak bosons and the weak mixing angle

In models in which the weak intermediate bosons are bound states consisting of spin 1 2 constituents the effective neutral current mixing angle sin 2θ W is related to the W wave function at the origin. Dynamical constraints for the bound state structure of the W-boson follow. Although the observed value of sin 2θ W is rather large, it seems possible to obtain the observed value in a dynamical mixing scheme. The weak bosons are extended objects, whose sizes are of the order of 10 −16 cm.

Future prospects for finding weak bosons

The Cern proton-an tiproton collider is due to come into operation in the second half of 1981. This will provide a total centre of mass energy o f 540 GeV with a design luminosity of 10 30 cm -2 s-1 , sufficient to produce easily detectable rates of charged and neutral weak interm ediate bosons, W ± and Z°. T he bosons are produced in the elementary collisions of quarks with antiquarks for w hich a well understood theoretical description exists. Two experim ents are being prepared that are optimized towards the detection of these particles through their decay modes Z° e+e~ or u + u - , W ± -> ev or uv. Both detectors incorporate electron and hadron calorimeters that are used to trigger the central track detectors on event candidates having high ‘transverse energy ’ deposition as well as to measure the electron energies precisely. One of the experiments has comprehensive muon detection and measurement. Prospects for studying the bosons at other proposed accelerators are mentioned.

Gauge hierarchies and the unification mass

It is shown that the existence of gauge hierarchies in unified theories of strong, weak and electromagnetic interactions permits unification of the three forces at energies as high as Planck mass. As examples, we discuss the O(10), E 6 and [SU(4)] 4 models. Implications for proton decay and for present and future weak intermediate boson phenomenology are considered.

On the transverse momentum distribution of massive lepton pairs

The experimentally measured q t distributions of massive lepton pairs produced in hadron collisions are compared with the predictions of QCD [1]. We demonstrate that a fair agreement may be achieved without the use of large transverse momenta of the constitunt quarks - owing to a specific double-logarithmic form factor which manifests itself in this process. A prediction for the q t distribution in weak intermediate boson production is also given.

Neutral-current effects in Bethe-Heitler pair production

We consider Bethe-Heitler pair production in which the exchanged photon is replaced with a neutral weak intermediate boson. The interference between this and the pure Bethe-Heitler amplitudes contributes to an asymmetry between the lepton pairs and, in addition, the leptons acquire a finite longitudinal polarization. Both effects are calculated and numerical examples are given in the standard Weinberg-Salam model.

The new elementary particles and charm

An elementary discussion of three theories which have recently been proposed to explain the existence of the new psi particles is given. These theories are: (1) the new particles are evidence for another basic interaction in nature; (2) They are the weak intermediate boson; (3) They are evidence for charm.

Consequences of direct ψ-lepton coupling

In this paper it is shown how the assumption of direct coupling of the recently discovered ~-partieles (i.~) to leptons and quarks can explain the unexpectedly large production of ~i (3.1 GeV) in nucleon-nucleon scattering in terms of the ~ branching ratios observed in the e+e- formation experiments. This result favours the interpretation of ~-particles as weak intermediate bosons rather than as long-lived hadrons (5.7). For the theoretical interpretation of ~ it is at present crucial to study both the e+e formation and the pp production results. For example, if we assume that in both

Strongly Interacting Weak Intermediate Bosons

Strongly Interacting Weak Intermediate Bosons

Production Cross Sections for Lee-Wick Massive Electromagnetic Bosons and for Spin-Zero and Spin-OneWBosons at High Energies

Production cross sections for three types of hypothetical particles are calculated in the presented paper. Several (Z, Z') cases were studied corresponding to elastic scattering off protons and neutrons (either free or embedded within a Fermi sea), coherent scattering off a nucleus, and inelastic scattering off a proton (in which case Z' denotes a nucleon resonance or hadronic system in the continuum). Detailed structure-function data are used to improve the accuracy of the inelastic scattering calculation. Results of calculations are given for beam energies between 50 and 10,000 GeV, and masses between 5 and 40 GeV for the massive Lee-Wick spin-1 boson. Cross sections were computed for resonant and semiweak processes. The production cross section of spin-zero weak intermediate bosons was found to be at least one order of magnitude smaller than for spin-1 weak bosons in nearly all regions of interest. The production cross section of spin-zero weak intermediate bosons for inelastic scattering off protons compares with that for elastic scattering in the regions of interest. In the case of massive spin-1 bosons and spin-1 weak intermediates, the main contribution to total production cross section off protons is elastic.

Detection of the Weak Intermediate Boson Through its Hadronic Decay Modes

Detection of the Weak Intermediate Boson Through its Hadronic Decay Modes

The theory of universal weak interactions and intermediate bosons

The theory of universal weak interactions and intermediate bosons

Weak intermediate bosons and unitary symmetry

The subject I am supposed to report on is intermediate bosons and unitary symmetry. This is a difficult subject for two reasons. The first is that there is at the present time no experimental evidence at all that these bosons really exist. The second one is that, even if they exist, we do not know whether they have really something to do with unitary symmetry. These are serious objections, especially the first. The reason why, in spite of it, I still want to give this talk is the following. Most theoretical physicists believe, I think, that we cannot live for ever with the weak interactions just being described by effective Fermi coupling constants and the like.

The intermediate boson — unitary triplet or octet

Within the framework of unitary symmetry we discuss two possible versions of a weak intermediate vector boson theory corresponding to a triplet and an octet model, respectively. The former has the advantage that it affords the basis for a possible explanation of the large mass of the intermediate boson in terms of strong interactions but it also requires the use of the fullU 3 group and not simply itsSU 3 subgroup. The latter can be accomodated within the existingSU 3 octet scheme. Both versions lead to the same effective four-fermion interaction for normal weak processes but may be distinguished by observation of the production cross-sections and decay modes of the intermediate bosons.