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M. Kirchbach

Publications and source records attributed to M. Kirchbach.

At least 55 records · Page 3Linked to original sources
arXiv2004

Massive Gauge Fields and the Planck Scale

The present work is devoted to massive gauge fields in special relativity with two fundamental constants-the velocity of light, and the Planck length, so called doubly special relativity (DSR). The two invariant scales are accounted for by properly modified boost parameters. Within above framework we construct the vector potential as the (1/2,0)x(0,1/2) direct product, build the associated field strength tensor together with the Dirac spinors and use them to calculate various observables as functions of the Planck length.

gr-qc↗
arXiv2004

High integer spins beyond the Fierz-Pauli Framework

We explicitly construct in the (1/2,1/2)X(1/2,1/2) representation space the operator of the squared Pauli-Lubanski vector and derive from it that the -6m^{2}eigensubspace (spin 2 in the rest frame), with well defined parity, is pinned down by the one sole equation, [ε_{μαβσ} ε^μ_{νδρ}p^σp^ρ-m^{2}g_{αβ}g_{ν\del ta}]h^{βδ}=0$.

hep-ph↗
arXiv2004

N and Delta Resonances in the Rigid Quark-Diquark Vibrator

A nearest-neighbor analysis of light flavor baryon mass spectra reveals striking degeneracy patterns- narrow mass bands populated by series of parity twins of steadily increasing spins. Each series terminates by an unpaired resonance of the highest spin in the group. We trace back such degenerate series of resonances (to be termed "mega states") to internal baryon structure dominated by a quark -(rigid di-quark) configuration. Nucleon and Delta spectra are, surprisingly enough, exact replicas to each other in the sense that each of them features three mega states of equal quantum numbers. We fit positions and splittings of the observed mega states by an algebraic Hamiltonian which translates into a potential that is a combination of Coulomb- and Morse like potentials and predict few more such degenerate series to be observed by the TJNAF missing resonance program. Finally, we explore consequences of the model for some electrodynamic properties of the spectra.

nucl-th↗
arXiv2004

Neutral Fermion Phenomenology With Majorana Spinors

We ask the question whether neutrino physics with momentum space Majorana spinors, the eigenvectors of the particle--antiparticle conjugation operator, C=iγ_2 K (with K standing for complex conjugation), is different but physics with Dirac spinors. First we analyze properties of Majorana spinors in great detail. We show that four dimensional, (4d), Majorana spinors are unsuited for the construction of a local quantum field because C invariance does not allow for a covariant propagation in four spinor dimensions, a conduct due to γ_2γ_μ= -γ_μ* γ_2. The way out of this dilemma is finding one more discrete symmetry that respects C invariance and gives rise to covariant propagators. We construct such a symmetry in observing that the parity operator, γ_0, ``ladders'' between (4d) rest-frame Majorana spinors, which takes us to eight dimensional spinor spaces. We build up two types of (8d) spaces-- one with a symmetric- and an other with an anti-symmetric off diagonal metric and calculate traces of single beta-- and neutrinoless double beta (0νββ) decays there. We find physics with (8d) Majorana spinors in the former space to be equivalent to physics with Dirac spinors in four dimensions. In the latter space we make the rare observation that in effect of cancellations triggered by the anti-symmetric off diagonal (8d) metric, the neutrino mass drops from the single beta decay trace but reappears in 0νββ, without the neutrino being massless in its free equation-- a curious and in principle experimentally testable signature for a non-trivial impact of Majorana framework.

hep-ph↗
arXiv2003

Spin and Resonant States in QCD

I make the case that the nucleon excitations do not exist as isolated higher spin states but are fully absorbed by (K/2,K/2)*[(1/2,0)+ (0,1/2)] multiplets taking their origin from the rotational and vibrational excitations of an underlying quark--diquark string. The Δ(1232) spectrum presents itself as the exact replica (up to Δ(1600)) of the nucleon spectrum with the K- clusters being shifted upward by about 200 MeV. QCD inspired arguments support legitimacy of the quark-diquark string. The above K multiplets can be mapped (up to form-factors) onto Lorentz group representation spaces of the type ψ_μ_1...μ_K, thus guaranteeing covariant description of resonant states. The quantum ψ_μ_1...μ_K states are of multiple spins at rest, and of undetermined spins elsewhere.

nucl-th↗
arXiv2003

Quantum states of indefinite spins: From baryons to massive gravitino

I review theory and phenomenology of (K/2,K/2)*[(1/2,0)+(0,1/2)] states. First I make the case that the observed nucleon and Delta (1232) excitations (up to Delta(1600)) are exhausted by unconstrained (K/2,K/2)*[(1/2,0)+(0,1/2)] states with K=1,3, and 5, which originate from rotational and vibrational excitations of an underlying quark--diquark configuration. Second, I consider the simplest case of K=1 and show that the γ^μψ_μ=0 constraint of the Rarita-Schwinger framework is a short-hand of: - 1/3 (1/m^2 W^2 +3/4)ψ_μ= ψ_μ, the covariant definition of the unique invariant subspace of the squared Pauli-Lubanski vector, W^2, that is a parity singlet and of highest spin-3/2 at rest. I suggest to work in the 16 dimensional vector spinor space Ψ= A *ψrather than keeping Lorentz and spinor indices separated and show that the above second order equation guarantees the covariant description of a has-been spin-3/2 states at rest without invoking further supplementary conditions. In gauging the latter equation minimally and, in calculating the determinant, one obtains a pathology-free energy-momentum dispersion relation, thus avoiding the classical Velo-Zwanziger problem of imaginary energies in the presence of an external electromagnetic field.

nucl-th↗
arXiv2002

Spacetime Structure of Massive Gravitinos

The talk presents an ab initio construct of the spacetime structure underlying massive gravitinos. We argue that single spin interpretation of massive gravitino is untenable, and that a spin measurement in the rest frame for an unpolarized ensemble of massive gravitinos, would yield the results 3/2^- with probability one half, and 1/2 with probability one half. The latter is distributed uniformly, i.e. as 1/4, among the two spin-1/2^+ and spin-1/2^- states of opposite parities. From that we draw the conclusion that the massive gravitino should be interpreted as a particle of multiple spin. We expect that a extension of this work to finite-range gravity shall endow the graviton with spins 0, 1, and 2 components.

hep-ph↗
arXiv2002

On the spin of gravitational bosons

We unearth spacetime structure of massive vector bosons, gravitinos, and gravitons. While the curvatures associated with these particles carry a definite spin, the underlying potentials cannot be, and should not be, interpreted as single spin objects. For instance, we predict that a spin measurement in the rest frame of a massive gravitino will yield the result 3/2 with probability one half, and 1/2 with probability one half. The simplest scenario leaves the Riemannian curvature unaltered; thus avoiding conflicts with classical tests of the theory of general relativity. However, the quantum structure acquires additional contributions to the propagators, and it gives rise to additional phases.

gr-qc↗
arXiv2002

Spacetime structure of massive gravitino

We present reasons as to why an ab initio analysis of the spacetime structure of massive gravitino is necessary. Afterwards, we construct the relevant representation space, and finally, give a new physical interpretation of massive gravitino.

hep-th↗
arXiv2001

Baryons in O(4) and Vibron Model

The structure of the reported excitation spectra of the light unflavored baryons is described in terms of multi-spin valued Lorentz group representations of the so called Rarita-Schwinger (RS) type (K/2, K/2)* [(1/ 2,0)+ (0,1/2)] with K=1,3, and 5. We first motivate legitimacy of such pattern as fundamental fields as they emerge in the decomposition of triple fermion constructs into Lorentz representations. We then study the baryon realization of RS fields as composite systems by means of the quark version of the U(4) symmetric diatomic rovibron model. In using the U(4)/ O(4)/ O(3)/ O(2) reduction chain, we are able to reproduce quantum numbers and mass splittings of the above resonance assemblies. We present the essentials of the four dimensional angular momentum algebra and construct electromagnetic tensor operators. The predictive power of the model is illustrated by ratios of reduced probabilities concerning electric de-excitations of various resonances to the nucleon.

hep-ph↗
arXiv2001

A critique on the supplementary conditions of Rarita-Schwinger framework

After a brief review of the celebrated 1941 paper of Rarita and Schwinger on the theory of particles with half-integral spins, we present an {\em ab initio} construct of the representation space relevant for the description of spin-3/2 particles. The chosen example case of spin-3/2 shows that covariance of a wave equation, and that of the imposed supplementary conditions, alone is not a sufficient criterion to guarantee the compatibility of a framework with relativity -- a lesson already arrived by Velo and Zwanziger. Here this same lesson is shown to be true at the level of the representation space without invoking any interactions. The presented detailed analysis forces us to abandon the single-spin interpretation of the Rarita and Schwinger framework, and suggests a new interpretation that fully respects the relativity theory.

hep-th↗
arXiv2001

(1/2,1/2) Representation space: An ab initio construct

A careful ab initio construction of the finite-mass (1/2,1/2) representation space of the Lorentz group reveals it to be a spin-parity multiplet. In general, it does not lend itself to a single-spin interpretation. We find that the (1/2,1/2) representation space for massive particles naturally bifurcates into a triplet and a singlet of opposite relative intrinsic parties. The text-book separation into spin one and spin zero states occurs only for certain limited kinematical settings. We construct a wave equation for the (1/2,1/2) multiplet, and show that the particles and antiparticles in this representation space do not carry a definite spin but only a definite relative intrinsic parity. In general, both spin one and spin zero are covariantly inseparable inhabitants of massive vector fields. This last observation suggests that scalar particles, such as the Higgs, are natural inhabitants of massive (1/2,1/2) representation space.

hep-th↗
arXiv2001

Primordial space-time foam as an origin of cosmological matter-antimatter asymmetry

The possibility is raised that the observed cosmological matter-antimatter asymmetry may reside in asymmetric space-time fluctuations and their interplay with the Stckelberg-Feynman interpretation of antimatter. The presented thesis also suggests that the effect of space-time fluctuations is to diminish the fine structure constant in the past. Recent studies of the QSO absorption lines provide a 4.1 standard deviation support for this prediction. Our considerations suggest that in the presence of space-time fluctuations, the principle of local gauge invariance, and the related notion of parallel transport, must undergo fundamental changes.

astro-ph↗
arXiv2000

Degeneracy Symmetry Of Baryon Spectra

We present a data-supported new interpretation of the Rarita-Schwinger fields which reveals a well-defined pattern in the masses, spins, and parities of the N-, Delta -, and Lambda -hyperon excitations and which allows to probe the scale of the chiral phase transition for baryons. The degeneracy symmetry of the baryonic spectra emerges to be Isospin(x)Space- Time.

hep-ph↗
arXiv2000

Classifying Reported and "Missing" Resonances According to Their P and C Properties

The Hilbert space H^3q of the three quarks with one excited quark is decomposed into Lorentz group representations. It is shown that the quantum numbers of the reported and ``missing'' resonances fall apart and populate distinct representations that differ by their parity or/and charge conjugation properties. In this way, reported and ``missing'' resonances become distinguishable. For example, resonances from the full listing reported by the Particle Data Group are accommodated by Rarita-Schwinger (RS) type representations (k/2,k/2)*[(1/2,0)+(0,1/2)] with k=1,3, and 5, the highest spin states being J=3/2^-, 7/2^+, and 11/2^+, respectively. In contrast to this, most of the ``missing'' resonances fall into the opposite parity RS fields of highest-spins 5/2^-, 5/2^+, and 9/2^+, respectively. Rarita-Schwinger fields with physical resonances as lower-spin components can be treated as a whole without imposing auxiliary conditions on them. Such fields do not suffer the Velo-Zwanziger problem but propagate causally in the presence of electromagnetic fields. The pathologies associated with RS fields arise basically because of the attempt to use them to describe isolated spin-J=k+1/ 2 states, rather than multispin-parity clusters. The positions of the observed RS clusters and their spacing are well explained trough the interplay between the rotational-like (k/2)(k/2 +1)-rule and a Balmer-like -(k+1)^{-2}-behavior.

nucl-th↗
arXiv2000

On the $η$ and f$_1$(1420) Couplings to the Nucleon

We consider neutral pseudoscalar, $η$, and axial vector, $f_1(1420)$, mesons in the OZI-rule-respecting flavor basis, $\lbrace (\bar s s), {1\over \sqrt{2}}(\bar u u + \bar d d)\rbrace$, and suggest a scenario for their coupling to the nucleon. Within this framework, the non--strange parts of the $ηN$ and f$_1 N$ couplings are modeled by means of triangular $a_0πN$, and $K K^* (Λ/Σ)$ vertices, while the strange ones partly proceed via Goldberger-Treiman relations, which have been concluded solely on the grounds of current universality. The suggested model explains the observed suppression of the $ηN$ coupling with respect to the constituent quark model expectations, and predicts the coupling of $f_1$ to the nucleon.

hep-ph↗
arXiv1999

Three-Flavor Symmetry of Hadrons Consistent With the Okubo-Zweig-Iizuka Rule

It is argued that the only three-flavor symmetry which is consistent with the Okubo-Zweig-Iizuka (OZI) rule, and is therefore dictated by the gluon gauge dynamics, is the heavy c quark limit of a certain U(4)_F subgroup (called S_OZI here) and defined as S_OZI= \lim_(m_c\to Λ_c) SU(2)_ud * SU(2)_cd * U(1) with the two SU(2) groups acting in turn onto the 1st and 2nd quark generations rather than Gell-Mann's eightfold SU(3)_F. Within this scheme the presence of non-strange quarkonium components in the wave function of the physical eta and f_1(1285) mesons appears necessarily through the violation of the OZI rule for the pseudoscalar and axial vector mesons by the anomalous axial U(1)_A baryon number current and not by a primordial octet flavor symmetry. The physical observable which selects the S_OZI over the SU(3)_F scheme is the non-isotriplet part of the neutral axial current. In the case of the S_OZI symmetry the only non-isotriplet neutral axial current having a well defined chiral limit is purely strange, while within the SU(3)_F framework it is the octet axial current which is supposed to be partially conserved. Accordingly, while in the latter case the tree level eta N coupling is of significant strength, its almost vanishes in the former, in agreement with data, thus confirming the relevance of the S_OZI symmetry.

hep-ph↗