Heavy Boson Research Articles

Condensation of light bosons in gauge theories

We investigate the thermodynamical properties of particular physical systems containing light bosons arising in gauge theories. Here we specifically consider certain decays involving heavy bosons in equilibrium with these light bosons and photons. We show explicitly how the necessary conditions for Bose-Einstein condensation of the light bosons are fulfilled in in these reactions. Finally we discuss some estimates on the critical densities for certain extreme cases.

Bounds on mixing between light and heavy gauge bosons

Upper bounds are derived for the mixing between light and heavy gauge bosons in terms of the closeness of the observed $W$ or $Z$ mass to the SU(2)\ifmmode\times\else\texttimes\fi{}U(1) prediction ${m}_{0}$. The mixing angles between light and heavy bosons with masses ${m}_{1}$ and ${m}_{2}$, respectively, are less than ${[\frac{({{m}_{0}}^{2}\ensuremath{-}{{m}_{1}}^{2})}{({{m}_{2}}^{2}\ensuremath{-}{{m}_{0}}^{2})}]}^{\frac{1}{2}}$. Existing data imply a limit of \ensuremath{\lesssim} 0.04 for the mixing angle between the $W$ and a 1-TeV heavy boson. A similar result holds for the $Z$ if there are no Higgs multiplets with $Ig\frac{1}{2}$ with significant vacuum expectation values.

Theory of the spin-1 bosonic liquid metal: Quasiparticle interactions and electrical resistivity in liquid metallic deuterium

We examine the low-temperature electrical resistivity of a hypothetical quantum plasma comprised of light fermions and heavy nonzero-spin bosons. The system corresponds to a possible quantum liquid metallic phase of highly compressed deuterium (electrons and deuterons). Bose condensation is assumed and in this state a new quadratic quasiparticle branch is present even with non-magnetic bare interactions. The consequences of these impurity-like excitations for electric current degradation are explored using the variational treatment of the Boltzmann equation. Quasiparticle collision rates among all possible types are analyzed. We find that the low-temperature electrical resistivity will exhibit an unusual $\ensuremath{\sim}{T}^{\frac{7}{2}}$ behavior and is attributable to electron scattering from the impurity-like excitations.

Computing the grand-unification mass in terms of the lengths of the fifth or sixth dimension

N = 2 supersymmetric GUTs can be formulated in a five-or six-dimensional spacetime. The grand unification mass m X can be computed in terms of the lengths of the extra compact dimensions: in the simplest case we find m X = (10π h ̵ /3L 5(6)c)n , where n is a fixed integer (or possibly a half-integer). The masses of the electroweak gauge bosons W± and Z are already present in the five- or six-dimensional theory, while the masses of the very heavy grand-unification bosons ( X ± 4 3 , Y ± 1 3 , … ) mostly originate from the large momenta they carry along the compact fifth or sixth dimension.

Heavy composite vector bosons and low-energy weak interactions

Models of quark-lepton substructure with composite W- and Z-bosons predict the existence of additional heavy vector bosons. We study a 15-plet of V-bosons which arise in a class of preon models with global Pati-Salam SU(4) invariance. An analysis of the weak interaction current-current lagrangian yields the V-masses as functions of sin 2θ w, M W and M Z. Furthermore, a non-vanishing C-parameter for neutral currents is predicted. The new vector bosons are expected to be heavier than ∼500 GeV.

Spinless bosons in electron-positron annihilation

The contributions to the processes\(e^ + e^ - \to \mu ^ + \mu ^ - ,q\bar q,\gamma \gamma ,e^ + e^ - \), mediated by scalar and/or pseudoscalar bosons are calculated. The constraints on their coupling constants and their masses are investigated as they arise from the radiative decayZ0→+e− γ and from the experimental data for the annihilation processes into lepton, photon and quark pairs. Data one+e−→μ+ μ−, γγ ande+e− seriously reduce the domain of coupling constants to leptons and photons still allowed by the probable value of the width ofZ0→e+e−γ. Experimentse+e−→μ+ μ−, γγ,e+e− at 45 GeV c.m.s. energy with a sensitivity of 10% will decide about the existence of a heavy spinless boson with the presumed phenomenological couplings to leptons and photons. Assuming universality of the coupling to leptons and quarks a conservative bound on the contribution toR arising from spinless boson exchange is already in conflict with the presumed radiative width ofZ0→e+e−γ.

Spinless boson decay and [formula omitted] events

A heavy spinless boson with derivative couplings to fermions can have a significant radiative decay into light fermions. This decay is considered as an alternative to Z decay to be a source for the anomalous l + l − γ events in Z searches. The kinematics of this decay is compatible with the events. Various production modes in p p collisions are compared and a possible connection to technicolor is mentioned.

Baryon wave functions and nucleon decay

We apply to nucleon decay the knowledge about the short-distance structure of baryon wave functions gleaned from QCD form factor calculations nd the J gY → p ̄ p decay rate. We review the uncertainties arising when current algebra and PCAC are used to relate N → ℓ + meson decay rates to 〈0| qqq|N〉 matrix elements. We show that the relevant matrix elements are not directly related to those of the leading twist operators “measured” in conventional high momentum transfer physics, but argue for an indirect based on models that fit both form factor and J Ψ decay data. We use these inputs to calculate the p → e + π 0 decay rate in minimal SU(5) and other grand unified theories (GUTs) for a specified value of the heavy vector boson mass m X . Our results combined with the recent experimental lower limit on this mode indicate that m X > 2 × 10 15 GeV in the minimal SU(5) GUT, and we derive analogous bounds for supersymmetric GUTs. Our calculated lifetime for a given value of m X is considerably shorter than previous estimates made using non-relativistic SU(6) or the bag model, a difference traceable to the different normalizations of 2 and 3 quark wave functions at short distances.

Proton decay induced by instantons inSU(5) grand unification

Instantons infinitesimally turned out of theSUc(3) subspace of spontaneously brokenSU(5) gauge theory induce a baryon number violating interaction proportional 1/μX2 like heavy vector boson exchange, but with a different tensor structure.

Free energy in the SU(5) model: Effects of heavy bosons

We calculate the Helmholtz free energy Ω in a gas of particles, described by the SU(5) theory, in the early Universe. We examine the contributions from massive vector bosons after symmetry breaking to the SU(3) c × SU(2) × U(1) y phase and find the temperature range where they are significant.

The neutron electric dipole moment in left-right symmetric gauge models

Vector boson and Higgs contributions to the neutron electric dipole moment d n are calculated to lowest order in a general gauge theory. To evaluate the exchange diagrams we use a simple harmonic oscillator bound state model of the neutron. We present estimates of the various contributions for the minimal SU(2) L × SU(2) R × U(1) model with a single scalar multiplet coupling to quarks. These estimates are illustrated by a detailed numerical study of a specific model of weak mixing angles. Allowing for maximally CP-violating phases the present experimental limit | d n| < 4 · 10 −25 e · cm would imply M W 2 ≳ 4 TeV (for m t = 30 GeV) for the mass of the heavy charged vector boson W 2. Whereas the neutral Higgs contributions turn out to be negligible, the charged Higgs contribution may become sizeable for large m t.

The free energy in the SU(5) model: Effects of heavy bosons: Gale P. Cook and K. T. Mahanthappa. University of Colorado, Boulder, Colorado 80309

The free energy in the SU(5) model: Effects of heavy bosons: Gale P. Cook and K. T. Mahanthappa. University of Colorado, Boulder, Colorado 80309

Wmagnetic moment in electroweak mixing and composite models and radiation zeros inqjq¯j→Wγ

The same experimental and theoretical constraints that are used to set limits on the masses of the weak bosons in the composite-model versions of electroweak mixing models are used to bound the magnetic-moment parameter of the $W$. We find in general electroweak mixing schemes, ones with additional heavy isospin-1 bosons (${W}^{\ensuremath{'}}$), that off-diagonal weak-boson electromagnetic interactions ($W{W}^{\ensuremath{'}}\ensuremath{\gamma}$ vertices) are allowed. The cross section for the process ${q}_{i}{\overline{q}}_{j}\ensuremath{\rightarrow}W\ensuremath{\gamma}$, which has been suggested as the best way to measure the $W$ moments, is generalized to include the effects of these off-diagonal couplings as well as arbitrary and independent $W$ magnetic dipole and electric quadrupole moments.

Stanford's hope for heavy boson

Linear machine may give an edge on CERN

Parity violation in elastic N-N scattering at high energies

Calculates the asymmetry in nucleon-nucleon elastic scattering at high energies arising from heavy boson exchange in the standard Weinberg-Salam model. By neglecting the strong interaction enhancement effects, the authors' result for p-n scattering is one order of magnitude higher than for p-p scattering. Enhancement effects increase the p-p asymmetry, which may become comparable with the p-n asymmetry. Their asymmetries, however, are too small if compared with the total cross section asymmetry measured at Argonne at 6 GeV/c on a water target.

Heavy quark jets as technicolour signatures in pp and pp̄ collisions

Within the framework of technicolour models many heavy bosons are expected. In this paper we propose heavy quark jets as a good way to find some of these particles. Our calculation suggest that the collider at BNL is the most adequate machine for such hunting.

Gauge model with heavy weak bosons and small additional neutral-current interaction proportional to charge squared

An SU(2)\ifmmode\times\else\texttimes\fi{}U(1)\ifmmode\times\else\texttimes\fi{}SU(2)\ensuremath{'} model is considered with symmetrical isovector gauge couplings. Heavy fermions with $V+A$ weak interactions are assigned to SU(2)\ensuremath{'}. The symmetry is broken by scalar multiplets $(T,Y,{T}^{\ensuremath{'}})=(\frac{1}{2},1,0),(0,1,\frac{1}{2}),(\frac{1}{2},0,\frac{1}{2})$ with respective vacuum expectation values $v\ensuremath{\ll}w\ensuremath{\sim}u$. The predictions are specified by one additional weak angle. The lightest weak bosons lie in the ranges $78&lt;~{M}_{{W}_{1}}&lt;~84$ GeV and $89&lt;~{M}_{{Z}_{1}}&lt;~100$ GeV. The smallness of the additional $C{Q}^{2}$ neutral-current interaction is explained.

Unextended Hypercolor and Unification

Phenomenologically acceptable quark and lepton masses result if the known light fermions are coupled to heavy fermions and bosons (mass order ${10}^{15}$ GeV) with SU(2) \ensuremath{\bigotimes} U(1)- breaking mass mixing of order 100 GeV. It is argued that adequate mixing may be obtained in a hypercolor theory which has a nontrivial fixed point. This is illustrated in a toy model based on SU(5) \ensuremath{\bigotimes} SU(2).

Baryon-to-entropy ratio and initial conditions of the Universe

We show that if the heavy bosons which enter into the grand-unified-theory mechanism for generating nonzero baryon number are created at an earlier stage by the expansion of the Universe and decay sufficiently early ($\mathrm{kT}\ensuremath{\gtrsim}3\ifmmode\times\else\texttimes\fi{}{10}^{15}$ GeV), then the baryon-to-entropy ratio will depend on the degree of anisotropy of the initial expansion. In the case of initially isotropic expansion, the baryon-to-entropy ratio will be roughly 30 times larger than in the standard scenario in which the particles are present initially in a thermal bath.

Fundamental coupling for weak interactions and masses

Weak interactions and the masses of mesons and of the neutron are described by fundamental couplings between muonic neutrinos and electronic leptons or nucleons by means of heavy bosons with spin 0. These couplings yield the charged- and neutral-current interactions, the masses of the muon and the pion as composite systems of leptons and the finite electromagnetic self-energy of the charged fermion. The parity violation in atomic transitions and the anomalous magnetic moment of the muon are the same as in gauge theory results. The theoretical cross-sections of muonic-neutrino scatterings by the electron agree with experimental data. The mass difference of proton and neutron is evaluated from a composite picture of the neutron.