Half-integral Charge Research Articles

Alternative [SU(3)]4 model of leptonic color and dark matter

The alternative [SU(3)]4 model of leptonic color and dark matter is discussed. It unifies at MU∼1014 GeV and has the low-energy subgroup SU(3)q×SU(2)l×SU(2)L×SU(2)R×U(1)X with (u,h)R instead of (u,d)R as doublets under SU(2)R. It has the built-in global U(1) dark symmetry which is generalized B–L. In analogy to SU(3)q quark triplets, it has SU(2)l hemion doublets which have half-integral charges and are confined by SU(2)l gauge bosons (stickons). In analogy to quarkonia, their vector bound states (hemionia) are uniquely suited for exploration at a future e−e+ collider.

EXOTIC FERMIONS AND BOSONS IN THE QUARTIFICATION MODEL

Exotic fermions of half-integral charges at the TeV energy scale are predicted by the quartification model of Babu, Ma and Willenbrock. We add to these one copy of their scalar analogs and discuss the ensuing phenomenological implications, i.e. radiative contributions to lepton masses and flavor-changing leptonic decays.

Suppressing the charge-ordering transition in LiMn2O4 through substitution of Li by Mg

The important electrode material LiMn2O4 undergoes a first order structural phase transition near room temperature. This transition, known to affect electrode characteristics, was long thought to result from the Jahn–Teller nature of Mn(III). However, Rodriguez-Carvajal and coworkers have recently established that with half-integral charge on Mn, what actually takes place at the transition is the crystallization of holes and electrons (charge ordering) in the crystal structure. Since the tendency to charge ordering is suppressed when charges on ions are not simple fractions, we have substituted Mg for Li to take Mn away from an average valence of 3.5. The transition is suppressed with as little as 4 atom% of Mg substitution for Li. The results suggest that the charge-ordering transition and Jahn–Teller distortions of the MnIIIO6 octahedra are distinct phenomena.

Brane creation in M(atrix) theory

We discuss, in the context of M(atrix) theory, the creation of a membrane suspendend between two longitudinal five-branes when they cross each other. It is shown that the membrane creation is closely related to the degrees of freedom in the off-diagonal blocks which are related via dualities to the chiral fermionic zero mode on a 0-8 string. In the dual system of a D0-brane and a D8-brane in type \IIA theory the half-integral charges associated with the ``half''-strings are found to be connected to the well-known fermion-number fractionalization in the presence of a fermionic zero mode. At sufficiently short distances, the effective potential between the two five-branes is dominated by the zero mode contribution to the vacuum energy.

Electrostatic potentials of the alpha helix dipole and of elastase

Molecular graphics has been used to display the electrostatic potentials of the α-helix dipole and that of elastase calculated using atomic charges obtained by a new, simple method 1–3. Calculations on the α-helix dipole support the simple dipole model in which the helix is represented by single, half integral charges at the helix termini. The potentials of elastase show some interesting features which may be related to the binding processes.

On states, on a lattice, with half-integral charge

In certain molecular models, and related one-dimensional field theories, localized objects appear with half-integral expectation values of charge. We consider whether these states are eigenstates of charge, with half-integral eigenvalue. We find that it is indeed so for a suitably diffuse definition of the charge operator in question. This diffuse charge operator has a spectrum which approaches a continuum. The analysis is made on a lattice, to avoid divergence ambiguities, and on a finite length, which is only subsequently made large. The half-integral charge phenomenon is not tied to solitons, but can also arise as an end effect.

Exotic Levels from Topology in the Quantum-Chromodynamic Effective Lagrangian

Skyrme has shown that the SU \ensuremath{\bigotimes} SU(2) chiral model has nontrivial topological sectors with static solutions for suitable Lagrangians. The baryon number $B$ and strangeness of these sectors have been studied, and the existence of bound states of the nucleon field to the lightest solitons is shown. It is found that there must be long-lived levels with $|B|\ensuremath{\gtrsim}6$ and $|s|\ensuremath{\gtrsim}6$ and $1.8 \mathrm{GeV}\ensuremath{\lesssim}m\ensuremath{\lesssim}5.6 \mathrm{GeV}$, some having half-integral charge and exotic relation between $B$ and $s$, that can be pair produced in, say, ${e}^{+}{e}^{\ensuremath{-}}$ collisions.

On solitons with half integral charge

Can certain soliton states, with half integral expectation value of charge, be also eigenstates of charge X with half integral eigenvalue? It can be so only with a somewhat sophisticated definition of charge.