Balmer-Like Series for Baryon Resonances

The pole positions of various baryon resonances have been found to reveal a well pronounced clustering, the so-called H"ohler cluster. In a previous work, the H"ohler clusters have been shown to be identical to Lorentz multiplets of the type (1/2+l', 1/2+l')*[(1/2,0)+(0,1/2)] with l' integer. Here we show that the cluster positions are well described by means of a Balmer-series like recursive mass formula.Comment: 5 pages LaTex, World Scientific style, two tables. A missing additive factor of +1 on the rhs of Eq. (2) has been inserted and thereby a misprint, not an error, correcte

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

Lorentz Multiplet Structure of Baryon Spectra and Relativistic Description

The pole positions of the various baryon resonances are known to reveal well-pronounced clustering, so-called Hoehler clusters. For nonstrange baryons the Hoehler clusters are shown to be identical to Lorentz multiplets of the type (j,j)*[(1/2,0)+(0,1/2)] with j being a half-integer. For the Lambda hyperons below 1800 MeV these clusters are shown to be of the type [(1,0)+ (0,1)]*[(1/2,0)+(0,1/2)] while above 1800 MeV they are parity duplicated (J,0)+(0,J) (Weinberg-Ahluwalia) states. Therefore, for Lambda hyperons the restoration of chiral symmetry takes place above 1800 MeV. Finally, it is demonstrated that the description of spin-3/2 particles in terms of a 2nd rank antisymmetric Lorentz tensor with Dirac spinor components does not contain any off-shell parameters and avoids the main difficulties of the Rarita-Schwinger description based upon a 4-vector with Dirac spinor components.Comment: 12 pages, LaTex, submitted to Mod. Phys. Lett.

Bethe-Salpeter equation with cross-ladder kernel in Minkowski and Euclidean spaces

Some results obtained by a new method for solving the Bethe-Salpeter equation are presented. The method is valid for any kernel given by irreducible Feynman graphs. The Bethe-Salpeter amplitude, both in Minkowski and in Euclidean spaces, and the binding energy for ladder + cross-ladder kernel are found. We calculate also the corresponding electromagnetic form factor.Comment: 4 pages, 3 figures. Contribution to the proceedings of the 18th International IUPAP Conference on Few-Body Problems in Physics (FB18), Santos, Brasil, August 21-26, 2006. To be published in Nucl. Phys.

DNA-viivakoodaus elintarvikkeiden aitoustutkimuksissa

Opinnäytetyön tarkoituksena oli ottaa käyttöön ja validoida DNA-viivakoodaus-menetelmä Elintarviketurvallisuusvirasto Eviralle. DNA-viivakoodaus oli alun perin ekologisiin tutkimuksiin kehitelty menetelmä, mutta pian siitä huomattiin olevan hyötyä myös muilla tutkimusalueilla, kuten elintarvikkeiden aitoustutkimuksissa. Elintarvikepetoksia ja etenkin mereneläviin kohdistuvia väärennöksiä paljastuu yhä enemmän maailmalla. Suomessa näitä väärennöksiä ei ole kovinkaan paljoa tutkittu aikaisemmin. DNA-viivakoodaus-menetelmä perustuu siihen, että genomista on valittu alue, jossa lajin sisällä emäsjärjestys vaihtelee mahdollisimman vähän ja eri lajien välillä suuresti. Lajit voidaan erottaa toisistaan viivakoodialueen sekvenssien perusteella. Eläinlajeilla käytetään usein mitokondriaalisen DNA:n sytokromi c oksidaasi 1 -geeniä (CO1) ja kasveilla kloroplastin maturaasi K (matK)- ja ribuloosi bisfosfaatti karboksylaasi iso alayksikkö (rbcL) -geenejä. Opinnäytetyön laboratorio-osuus suoritettiin pääosin Yhdysvaltain elintarvike- ja lääkevirasto FDA:n laatiman työohjeen mukaisesti. Kalanäytteestä eristettiin DNA, josta monistettiin PCR:llä tietty nukleotidijakso. PCR-tuote puhdistettiin ja sekvensoitiin. Sekvensoinnin tulokset käsiteltiin bioinformatiikan työkaluin ja saatuja sekvenssejä verrattiin sekvenssitietokantoihin, jolloin saatiin selville näytteen kalalaji. Menetelmän käyttöönotto onnistui hyvin. DNA-eristys onnistui, mikäli näytemäärä ei ollut liian suuri. Erilaiset matriisit, kuten savustettu tai suolattu kala, eivät aiheuttaneet ongelmia. Poikkeuksena olivat ainoastaan liian prosessoidut tuotteet, kuten öljyyn säilötty purkkikala. Työssä käytetyt alukkeet toimivat usealle lajille, ja lajintunnistus onnistui vähintään sukutasolle asti. Alustavien tutkimusten perusteella samat alukkeet ja menetelmä soveltuvat myös eläinlajien määritykseen.The purpose of this Bachelor’s thesis was to implement and validate a DNA barcoding method for Finnish Food Safety Authority Evira. DNA barcoding method was originally developed for ecological studies, but soon it was found to be useful in other areas of research as well, such as food authenticity studies. Increasing amount of food frauds, especially seafood forgeries have been found around the world. In Finland, these forgeries have not been studied intensively until recently. DNA barcoding method is based on analysis of a selected area in the genome. The selected genome area should have as little sequence variety as possible within a species and as much as possible between different species. Species can be identified by the sequences of the barcode region. The cytochrome c oxidase subunit 1 gene (CO1) from mitochondrial DNA is often used with animal identification, and maturase K (matK) and ribulose bisphosphate carboxylase large chain (rbcL) genes from the chloroplast are used when researching plants. The laboratory work in this thesis was carried out mainly in accordance with the standard operating procedure made by the U.S. Food and Drug Administration FDA. The DNA was extracted from the fish sample, and a specific nucleotide sequence was amplified from the DNA. The PCR product was purified and sequenced. The results of the sequencing were processed with bioinformatics tools, and the gained sequences were compared to sequence databases to identify the species of the fish sample. The implementation of this method was successful. DNA extraction succeeded if the sample was not too large. Different matrices, such as smoked or salted fish, did not cause problems. The only exceptions were too far processed products, such as fish canned in oil. The primers used in this thesis were functional in many species and the identification of the species was successful until the family level at least. On the bases of the preliminary studies, the same primers and method are also suitable for the identification of several animal species

Octet and Decuplet Baryons in a Confining and Covariant Diquark-Quark Model

We treat baryons as bound states of scalar or axialvector diquarks and a constituent quark which interact through quark exchange. We obtain fully four-dimensional wave functions for both octet and decuplet baryons as solutions of the corresponding Bethe-Salpeter equation. Applications currently under investigation are: electromagnetic and strong form factors and strangeness production processes.Comment: 4 pages, 1 figure; talk given by R. Alkofer at PANIC 9

Does the effective Lagrangian for low-energy QCD scale?

QCD is not an approximately scale invariant theory. Hence a dilaton field is not expected to provide a good description of the low-energy dynamics associated with the gluon condensate. Even if such a field is introduced, it remains almost unchanged in hadronic matter at normal densities. This is because the large glueball mass together with the size of the phenomenological gluon condensate ensure that changes to that condensate are very small at such densities. Any changes in hadronic masses and decay constants in matter generated by that condensate will be much smaller that those produced directly by changes in the quark condensate. Hence masses and decay constants are not expected to display a universal scaling.Comment: 7 pages (RevTeX), MC/TH 94/0