Denis Parganlija

Wiedner Hauptstr. 8-10

1040 Vienna

Austria

E-Mail: denisp (at) hep.itp.tuwien.ac.at
Tel.: +43 1 58 80 11 36 35
Fax: +43 1 58 80 11 36 99

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Research Interests

I am interested in various aspects of Quantum Chromodynamics (QCD):

- Meson Spectroscopy: Quarkonia, Tetraquarks, Glueballs via Effective Field Theories and Holographic QCD

- QCD at Finite Densities: Compact Stars.

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What I Do:

I am currently interested in glueballs, bound states of gluons (gauge bosons of QCD). These “states of pure energy” should appear as a result of the strong interaction just as, e.g., protons, neutrons and pions do – the difference being that the latter are basically composed of quarks rather than gluons. The trouble is that glueballs have still not been discovered in experiments and my work is aimed at supplying their observables (masses, decay widths) that can be found in the data. An interesting aspect of the story is that glueballs rarely come alone: they can be mixed with non-glueball, strongly interacting states and only the product of their interference should be observable experimentally. It is not yet quite clear which consequences this has – and my work is aimed at helping resolve this problem as well.

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Biographical Notes:

Ø Currently: Research Fellow at Vienna University of Technology

Ø 2012: PhD exam, Institute for Theoretical Physics, Frankfurt University
PhD thesis: Quarkonium Phenomenology in Vacuum

Ø 2007: Diploma exam in physics, Frankfurt University
Diploma thesis: Pion-Pion Scattering in a Gauged Linear Sigma Model with Chiral U(2)_L x U(2)_R Symmetry

Ø 2002: Graduation at the Comprehensive Grammar School in Zenica/Bosnia-Herzegovina

Awards:

Ø 2008: Scholarship, Polytechnical Society Foundation Frankfurt am Main

Ø 2004: Scholarship, Friedrich Ebert Foundation

My full CV is available here.
My list of publications on INSPIRE can be found here.

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My PhD thesis in 304 Words

The thesis had scalar, pseudoscalar, vector and axial-vector mesons – both nonstrange and strange – as its topic. The basic premise was simple: a glance at experimental data, e.g., those supplied by the Particle Data Group (PDG) reveals that the number of the isosinglet scalar mesons is larger than what would be expected from an antiquark-quark (quarkonium) structure. Hence not all of them can be quarkonia and the main topic of my thesis was the search for those isosinglet scalars that are consistent with the quarkonium structure.

However, it is not as simple as considering just scalars: experiments also tell us that scalars interact with other meson classes: pseudoscalars, vectors and axial-vectors. Hence I used one model for all of them: an Extended Linear Sigma Model (eLSM) with three quark flavours (eLSM) to fit some and predict other meson masses and decay widths.
The result was that scalar antiquark-quark states are heavier than perhaps naively expected: they are located above 1 GeV in the meson spectrum. Additionally, similar statements can be made about other mesons the nature of which is under discussion: I found a₁(1260) to represent a quarkonium as well.

So why is this important? For at least two reasons: firstly, we obtain a closer sense about classification of the large number of meson states. (Those that are not composed of quarks could be glueballs, see above what I do now.) Secondly, signatures of the so-called quark-gluon plasma, a state of matter that existed shortly after the Big Bang, rely for example on the degeneration of chiral partners – mesons of the same structure but with some varying quantum numbers. The identification of chiral partners is thus extremely important and it can only be done if meson structures are known. Hence the need to gain insight into their inner dealings, such as done in my thesis.