Neutral Scalar Particle Research Articles

Nonleading radiative contributions to low-energy N=1 supergravity theories.

Radiative contributions to the low-energy effective potential are presented in the neutral-Higgs-boson sector in the dimensional-transmutation scenario for which the lightest Higgs boson is massless at the tree level. Their possible role in breaking the local electroweak gauge symmetries is discussed. Predictions for the radiatively induced mass ${m}_{R}$ of the neutral scalar Higgs particles are given for models with three- and four-particle generations. Typically, for three generations ${m}_{R}$\ensuremath{\lesssim}6 GeV while for a fourth generation with equal up- and down-quark masses , \ensuremath{\le}90 GeV dictated by a theoretically plausible realization of the radiative symmetry breaking. For a nondegenerate fourth generation ), we find ${m}_{R}$\ensuremath{\lesssim}11 GeV. In all cases it is found that there is no lower bound on ${m}_{R}$, in contrast with the Weinberg-Linde result for the nonsupersymmetric standard theory.

Extended strongly interacting Higgs theories.

For a large Higgs-boson mass, the Higgs/gauge-boson sector of the standard SU(2)/sub L/ x U(1) electroweak theory becomes strongly interacting suggesting that the neutral (iso)scalar particle in the theory might actually be a bound state of longitudinally polarized gauge bosons, W/sub L//sup +/W/sub L//sup -/ and Z/sub L//sup 0/Z/sub L//sup 0/. We investigate SU(2)/sub L/ x U(1) models with nonstandard Higgs sectors to determine whether charged scalar bound states, i.e., W/sub L//sup + -/Z/sub L//sup 0/ or W/sub L//sup +/W/sub L//sup +/, can possibly appear at low mass mimicking the physical charged Higgs particles present in these theories. We also examine the strongly interacting Higgs sector in an electroweak model based on SU(2)/sub L/ x U(1) x U(1) as an example where the gauge group is extended.

Minimal low energy supersymmetry: bounds on Higgs masses

The minimal model based on spontaneously broken supergravity predicts upper bounds on the mass of a neutral scalar Higgs particle. It is shown that these bounds are very restrictive if the mass of the top quark is less than 50 GeV. For a top quark mass of 30 (40) GeV the upper bound on the light Higgs is given by 11 (24) GeV respectively.

Perturbation theory for nonderivative nonpolynomial Lagrangians

We present a regularization scheme for deriving finite, unitary, and causal amplitudes to each order in the major coupling constant for nonderivative nonpolynomial Lagrangians for the self-interaction of massless neutral scalar particles. The results are shown to contain no arbitrary constants, though these may be introduced consistently into the superpropagator, the second-order contribution.

Renormalizable Lagrangians for massive Yang-Mills fields

Renormalizable models are constructed in which local gauge invariance is broken spontaneously. Feynman rules and Ward identities can be found by means of a path integral method, and they can be checked by algebra. In one of these models, which is studied in more detail, local SU(2) is broken in such a way that local U(1) remains as a symmetry. A renormalizable and unitary theory results, with photons, charged massive vector particles, and additional neutral scalar particles. It has three independent parameters. Another model has local SU(2)⊗U(1) as a symmetry and may serve as a renormalizable theory for ϱ-mesons and photons. In such models electromagnetic mass-differences are finite and can be calculated in perturbation theory.

A derivation of upper bounds for forward and fixed-momentum-transfer scattering amplitudes at high energies

The purpose of this short paper is to give, using continuous variables, a simple derivation of high-energy upper bounds for forward and nearly forward (fixed momentum transfer) scattering amplitudes which satisfy the analyticity properties of axiomatic quantum field theory. As usual, we consider the case of neutral scalar particles of equal mass. Our starting point is the Oran,s representation of the scattering amplitude (~)

The Continuous -Ray Spectrum

QUANTUM mechanics deals with object systems composed of only a few particles out of the total number of particles in the universe. The particles of the local object system, which may be an atom or atomic nucleus, are supposed to be incapable of dropping into vacant energy levels in the back ground consisting of the unspecified particles of the universe. Also an unspecified particle of the back ground is supposed to be incapable of falling into one of the vacant levels of the local specified system. As Eddington1 has pointed out, this means that quantum mechanics postulates that the levels of the background are all below the ground-level of the local object system, and further, that all the levels in the background are occupied by one particle, a neutral scalar particle in Eddington's theory, in each level in accordance with the exclusion principle. The limit energy of the unspecified background particles corresponds to the threshold energy of the local specified system. The background forms a uniform isotropic comparison fluid which is postulated by our statement of the quantum theory.