Group for chiral field theories

at  the Institute for Theoretical Physics, J.W. Goethe University, Frankfurt am Main

The aim of the chiral group is the investigation of modern topics of hadron physics both in the vacuum and at nonzero temperature and densities. Spectroscopy and phenomenology of mesons and baryons, the study of chiral partners, spontaneous symmetry breaking and its restoration in a thermal and dense medium are the main interests.

Regular meetings are hold to discuss the above subjects: present schedule here.

Old meeting of the chiral group (up to Wi. Se. 2014/2015): here.


Group members

Group leaders

Prof. Dr. Dirk H. Rischke link zur Homepage     and   Prof. Dr. Francesco Giacosa link zur Homepage                           



Dr. Khaled Teilab

Scientific interests: “Nucleon-antinucleon scattering and production of ω and η mesons.”

Organizer of the chiral group meeting: link


Ph.D. students

Anja Habersetzer: link to homepage

Scientific interests: “Spectral function of the a1 and rho mesons“ and “Dilepton production in nucleon-nucleon scattering”.

Diploma thesis: “Spectral densities of the tau lepton in a global U(2)xU(2) linear sigma model with electroweak interaction” (pdf)




Lisa Olbrich: link to homepage

Scientific interests: Baryons with strangeness in the eLSM.

Master thesis (2014): “Phenomenology of baryons in the eLSM” (pdf).

Bachelor thesis (2012): “Phenomenology of pseudo-vector mesons and mixing effects in the kaonic sector” “(in German) (pdf)



Florian Divotgey:

Master thesis (2015): “The low-energy constants of the extended Linear Sigma Model at tree-level” (pdf).

Bachelor thesis (2012): “Phenomenology of axial-vector mesons and mixing effects in the kaonic sector” “(in German) (pdf)


Juergen Eser

Scientific interests: “FRG in chiral models”.


Master students:


Jonas Schneitzer

Scientific interests: “Inhomogeneous chiral condensation”.

Bachelor thesis (2014): “ Third-order correction to the decay S -> φφ” (in German) (pdf).


Julia Sammet

Scientific interests: Decays of the vector glueball in a chiral approach.

Scientific interests: “Decays of (pseudo)vector glueballs”. (in German) (pdf)




Bachelor students:


Kevin Nikolla

Randomized pulsed measurement in Quantum Mechanics.



External members


Dr. Werner Deinet 

Scientific interests: “Nucleon-antinucleon scattering and the deuteron.”



Dr. Susanna Gallas link to homepage

Scientific interests: “Baryons in the parity doublet model”.

PhD thesis (2010): „The nucleon and its chiral partner “(in German) (pdf)

(high-school teacher since 1/11/2013, but still active member of the group)


Mara Grahl:              

Scientific interests: “FRG in chiral models”.

PhD thesis (2014): “Low-energy effective models for two-flavor

quantum chromodynamics and the universality hypothesis” (pdf).

Diploma thesis: “The O(N=2) model in polar coordinates at nonzero temperature” (pdf)




Former members:

Dr. Denis Parganlija,

Diploma thesis (2008) „pion-pion scattering in a gauged linear sigma model“ (in German) (pdf)

Ph.D.  thesis (2012)  „Quark-antiquark phenomenology in vacuum” (pdf)



Dr. Elina Seel:

Scientific interests: “Quantum field theories with trace anomaly”.

Diploma thesis (2009): “Dependence on the representation of O(2)-symmetric models at nonzero temperature” (in German) (pdf)



Dr. Achim Heinz:


Scientific interests: “QCD under extreme conditions: the inhomogeneous condensation” (pdf).

Diploma thesis (2009): “The influence of a light tetraquark on the chiral phase transition ” (in German) (pdf)


Dr. Walaa Eshraim: link to homepage


Scientific interests: Pseudoscalar glueball and charmed mesons in the eLSM”. (pdf)


Dr. Stanislaus Janowski:


Scientific interests: “Phenomenology of glueballs and scalar-isoscalar quarkonia within an e_ective hadronic model of QCD”. (pdf)

Diploma thesis (2010): “Phanomenology of the dilaton in a chiral model with (axial-)vector mesons” (in German)  (pdf)



Dr. Thomas Wolkanowski-Gans: link to homepage


PhD thesis (2016): “Dynamical generation of hadronic resonances in effective models with derivative interactions”. (pdf).

Diploma thesis (2013): “Resonances and poles in the second Riemann sheet” (pdf)



Aleksander Nikolla:

Diploma thesis (2015): 'Chiral phase transitions and expansion of the Universe in a phenomenological model of QCD'

Diploma thesis in German: pdf.



Christian Reisinger:

Bachelor thesis (2014): “Phenomenology of the excited vector meson nonet(s)” (pdf).


Adrian Königstein

Bachelor thesis (2014): “Tensor fields in QFT and phenomenology of pseudotensor mesons” (pdf).



Nils Saß

Bachelor thesis (2014): “Decays of (pseudo)tensor glueballs in the eLSM” (pdf).


Sabrina Hempel

Bachelor thesis (2014): “Mixing of scalar fields at the one-loop order”. (pdf)



Klaus Neuschwander

Bachelor thesis (2012): „Three-body decays in effective hadronic models“ (in German) (pdf)


Antje Peters

Bachelor thesis (2012): „Baryonic decays in the eLSM“ (in German) (pdf)


Stefan Strüber

Diploma thesis (2005): “Self-consistent calculation of the Masses of (pseudo)scalar and (axial-)vector mesons in the medium” (in German) (pdf)


Local and international collaborations:

Juergen Schaffner-Bielich and Marc Wagner, Goethe University, Frankfurt (Germany).

Gyuri Wolf, Peter Kovacs, and Miklos Zetenyi, Wigner Research Center of Budapest (Hungary).


Denis Parganlija, Vienna University of Technology (Austria).


Giuseppe Pagliara, INFN and University of Ferrara (Italy).


Pedro Bicudo, IST, Lisboa (Portugal).


Recent published works in peer-review journals:

a) The extended Linear Sigma model (eLSM)

(A summarizing talk about the eLSM  is the “Antrittsvorlesung” held by F. Giacosa in Frankfurt on the 15/5/2013: pdf.)


S. Janowski, F. Giacosa and D. H. Rischke,

 Is f0(1710) a glueball?,
 Phys. Rev.  D 90 (2014) 11,  114005


D. Parganlija, P. Kovacs, G. Wolf, F. Giacosa, and D. H. Rischke

Meson vacuum phenomenology in a three-flavor linear sigma model with (axial-) vector mesons.

Phys.Rev. D87 (2013) 014011 


Walaa I. EshraimStanislaus Janowski, Francesco Giacosa, and Dirk H. Rischke

Decay of the pseudoscalar glueball into scalar and pseudoscalar mesons.  

Phys.Rev. D87 (2013) 054036.


Stanislaus Janowski, Denis Parganlija, Francesco Giacosa, Dirk H. Rischke

The Glueball in a Chiral Linear Sigma Model with Vector Mesons.

Phys. Rev. D 84, 054007 (2011).    

Denis Parganlija, Francesco Giacosa, Dirk H. Rischke,

Vacuum Properties of Mesons in a Linear Sigma Model with Vector Mesons and Global Chiral Invariance.

Phys. Rev. D 82, 054024 (2010).

Susanna Gallas, Francesco Giacosa, Dirk H. Rischke,

Vacuum phenomenology of the chiral partner of the nucleon in a linear sigma model with vector mesons.

Phys. Rev. D 82 014004, 2010.


b) Studies at nonzero temperature and density:

A. Heinz, F. Giacosa and D. H. Rischke,

Chiral density wave in nuclear matter

Nucl. Phys. A, in press.   


M. Grahl and D. H. Rischke,

Functional renormalization group study of the two-flavor linear sigma model in the presence of the axial anomaly.

Phys. Rev. D 88 (2013) 056014.


Mara Grahl, Elina Seel, Francesco Giacosa, Dirk H. Rischke

The O(2) model in polar coordinates at nonzero temperature.

Phys. Rev. D 87 (2013) 096014.


Elina Seel, Dominik Smith, Stefano Lottini, and Francesco Giacosa

Thermodynamics of the O(3) model in 1+1 dimensions: lattice vs. analytical results. 

JHEP 1307 (2013) 010.


P. Bicudo, F. Giacosa and E. Seel,

Computation of Pion and Kaon Heavy Ion Multiplicities in a Gluon-Meson Model.

Phys. Rev. C 86 (2012) 034907.

Elina Seel, Stefan Struber, Francesco Giacosa, Dirk H. Rischke

Study of chiral symmetry restoration in linear and nonlinear O(N) models using the auxiliary field method.

Phys. Rev. D  86 (2012) 125010.


F. Giacosa,
Analytical study of a gas of gluonic quasiparticles at high temperature: Effective mass, pressure and trace anomaly.

Phys. Rev. D 83 (2011) 114002.

Achim Heinz, Francesco Giacosa, Dirk H. Rischke

Restoration of chiral symmetry in the large-N_c limit.   

Phys. Rev. D 85 (2012) 056005.


Susanna Gallas, Francesco Giacosa, Giuseppe Pagliara

Nuclear matter within a dilatation-invariant parity doublet model: the role of the tetraquark at nonzero density.

Published in Nucl. Phys. A872 (2011) 13-24.


Achim Heinz, Stefan Struber, Francesco Giacosa, Dirk H. Rischke,

Role of the tetraquark in the chiral phase transition.

Phys. Rev. D 79 037502, 2009.


S. Strüber and D. H. Rischke,
Vector and axialvector mesons at nonzero temperature within a gauged linear sigma model.
Phys. Rev. D 77 (2008) 085004.


c) Other papers on hadron phenomenology (tetraquarks, mixing, …):


J. Schneitzer, T. Wolkanowski and F. Giacosa,
The role of the next-to-leading order triangle-shaped diagram in two-body hadronic decays,
Nucl. Phys. B 288 (2014) 287. 
F. Divotgey, L. Olbrich, and F. Giacosa,
Phenomenology of axial-vector and pseudovector mesons: decays and mixing in the kaonic sector.

Eur. Phys. J. A 49 (2013) 135.

F. Giacosa and T. Wolkanowski,
Propagator poles and an emergent stable state below threshold: general discussion and the E(38) state.
Mod. Phys. Lett. A 27 (2012) 1250229.


F. Giacosa,
Spontaneous breaking of chiral symmetry, and eventually of parity, in a sigma-model with two Mexican hats.

Eur. Phys. J. C 65 (2010) 449.

Francesco Giacosa,

Dynamical generation and dynamical reconstruction.

Phys. Rev. D 80 074028, 2009.

Francesco Giacosa, Giuseppe Pagliara,

Spectral functions of scalar mesons.

Published in Phys. Rev. C 76 065204, 2007.


Francesco Giacosa,

Mixing of scalar tetraquark and quarkonia states in a chiral approach.

Published in Phys. Rev. D 75 054007,2007.

Francesco Giacosa,

Strong and electromagnetic decays of the light scalar mesons interpreted as tetraquark states,

Phys. Rev. D 74 014028, 2006.