![]() Townhall in Hagen/Westfalen Dr. habil. Stefan Groote
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"Mathematischer Vorkurs Frühjahr 2005" (in German)
My habilitation thesis (Habilitationsschrift)
pictures from the factulty reception of Marcus Mauser after his defense are now found on his own homepage!
instead: pictures of (parts of the) ThEP group taken for a present for Dirk Kreimer in occasion of his departure.
Reference to my PhD thesis (Dissertation)
The second subject of my thesis, the anomalous dimension in the calculation of two-loop corrections to the mesonic and baryonic vertex, was result of a collaboration between Prof. Körner, Dr. Oleg I. Yakovlev and me. Using these results, we calculated first order radiative corrections to to the two-point correlator for the baryonic current related to this the radiative corrected diagonal and non-diagonal QCD sum rules.
On February 21, 1997, I passed my PhD examination with "magna cum laude".
Since March 1996 I co-attended the work of Dipl. Phys. Alfonso Leyva, PhD student at Prof. Körner, whos first subject was gluon polarization effects. For the second theme, namely the calculation of spin-spin correlations in electron-positron-annihilations into quarks and gluons, we were joined by Prof. Körner's PhD student Dipl. Phys. Volker Kleinschmidt since February until he left the Institute, since April by Dipl. Phys. Marcus Mauser.
In collaboration with Prof. Dr. Karl Schilcher and Prof. Dr. J. Körner I worked on the improvement for the accuracy of the QED coupling constant on the Z pole. We were joined by Dr. Alexei A. Pivovarov, who was guest at Mainz for several times. We extended the analysis to high order relations between physical observables as test for perturbative QCD and analyzed the resummation techniques in tau decays. We also searched for new calculation techniques for sunset diagrams. In this curse we were able to find some configuration space techniques to handle sunset-type diagrams, called water melons, and could reproduce the transcendental numbers obtained in the tetrahedron diagrams of three-loop bubbles within easier topologies. We shall continue the collaboration also be incorporating calculations on radiative corrections to massive baryonic correlators.
In summer 1997 and 1998, Dr. Andrei G. Grozin was guest at the ThEP working group. In cooperation with him we started a project for calculating electric and magnetic formfactors for massive quarks.
S. Groote, J.G. Körner, M.M. Tung
(MZ-TH / 95-09):
"Longitudinal contribution to the longitudinal polarization of quarks
produced in electron-positron-annihilation: an O(alpha_s) effect",
Z. Phys. C70 (1996) 281-290
S. Groote, J.G. Körner
(MZ-TH / 95-17):
"Transverse polarization of top quarks produced in
electron-positron-annihilation at O(alpha_s)",
Z. Phys. C72 (1996) 255-261
S. Groote, J.G. Körner, M.M. Tung
(MZ-TH / 95-19):
"Polar angle dependence of the alignment polarization of quarks
produced in electron-positron-annihilation",
Z. Phys. C74 (1997) 615-629
S. Groote, J.G. Körner, O.I. Yakovlev
(MZ-TH / 96-06):
"Two-loop anomalous dimensions of heavy baryon currents
in heavy quark effective theory",
Phys. Rev. D54 (1996) 3447-3456
S. Groote, J.G. Körner, O.I. Yakovlev
(MZ-TH / 96-21):
"QCD sum rules for heavy baryons at next-to-leading order in alpha_s",
Phys. Rev. D55 (1997) 3016-3026
S. Groote, J.G. Körner, J.A. Leyva
(MZ-TH / 96-34):
"Gluon polarization in electron-positron to top-antitop-gluon",
Phys. Rev. D56 (1997) 6031-6034
S. Groote, J.G. Körner, A.A. Pivovarov
(MZ-TH / 97-03):
"Resummation analysis of the tau decay width using the four-loop
beta-function",
Mod. Phys. Lett. A13 (1998) 637-650
S. Groote,
(MZ-TH / 97-05):
"Two-loop anomalous dimensions of heavy baryon currents in heavy quark
symmetry",
Talk given on the
2nd Triangle School in Particle Physics,
Prague, Czech Republic, September 2-10, 1996
S. Groote, J.G. Körner, A.A. Pivovarov, K. Schilcher
(MZ-TH / 97-09):
"New high order relations between physical observables in perturbative
QCD",
Phys. Rev. Lett. 79 (1997) 2763-2766
S. Groote, J.G. Körner, A.A. Pivovarov
(MZ-TH / 97-16):
"Perturbative relations between electron-positron annihilation and tau decay
observables including resummation effects",
Phys. Lett. 407 B (1997) 66-72
S. Groote, J.G. Körner, J.A. Leyva
(MZ-TH / 97-17):
"Gluon polarization in electron-positron to electron-positron to
top-antitop-gluon: polar angle dependence and beam polarization effects",
Eur. Phys. J. C7 (1999) 49-59
S. Groote, J.G. Körner, O.I. Yakovlev
(MZ-TH / 97-19):
"An analysis of diagonal and non-diagonal QCD sum rules for heavy baryons at
next-to-leading order in alpha_s",
Phys. Rev. D56 (1997) 3943-3954
S. Groote, J.G. Körner, J.A. Leyva
(MZ-TH / 97-27):
"O(alpha_s) corrections to longitudinal spin-spin correlations in
electron-positron to quark-antiquark",
Phys. Lett. 418 B (1998) 192-198
S. Groote
(MZ-TH / 97-34):
"Analyzing QCD sum rules for heavy baryons at next-to-leading order in
alpha_s", Proceedings of the IVth International Workshop "Progress in
Heavy Quark Physics", Rostock, September 20-22, 1997, pages 195-198
S. Groote, J.G. Körner, J.A. Leyva
(MZ-TH / 97-39):
"On the rigidity of back-to-back top quark pairs in electron-positron
annihilation",
Nucl. Phys. B527 (1998) 3-20
S. Groote, J.G. Körner, K. Schilcher, N.F. Nasrallah
(MZ-TH / 98-02):
"QCD sum rule determination of alpha(M_Z) with minimal data input",
Phys. Lett. 440 B (1998) 375-385
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 98-09):
"On the evaluation of sunset-type Feynman diagrams",
Nucl. Phys. B542 (1999) 515-547
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 98-12):
"A new technique for computing the spectral density of sunset-type
diagrams: integral transformation in configuration space",
Phys. Lett. 443 B (1998) 269-275
M. Fischer, S. Groote, J.G. Körner and M.C. Mauser, B. Lampe
(MZ-TH / 98-47):
"Polarized top decay into polarized W",
Phys. Lett. 451 B (1999) 406-413
J.G. Körner and S. Groote
(MZ-TH / 98-63):
"Heavy Baryons: Status and overview (theory)",
Invited talk given by J.G. Körner at the 8th International Conference on
the Structure of Baryons (BARYONS'98), Bonn, Germany, 22-26 September 1998,
published in the Proceedings "BARYONS '98", edited by D.W. Menze and B. Metsch
(World Scientific, Singapore, 1999) pages 232-245.
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 99-07, CLNS / 99-1606):
"Configuration space based recurrence relations for sunset-type diagrams",
Eur. Phys. J. C11 (1999) 279-292
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 99-13, CLNS / 99-1613):
"Transcendental numbers and the topology of three-loop bubbles",
Phys. Rev. D60 (1999) 061701
S. Groote
(MZ-TH / 99-18, CLNS / 99-1619):
"Local and global duality and the determination of alpha(M_Z)", Proceedings of
the conference "High Energy Physics at the Millennium (MRST'99)", Ottawa,
Canada, May 10-12, 1999, pages 124-131
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 99-49, CLNS / 99-1647):
"O(alpha_s) corrections to the correlator of finite mass baryon currents",
Phys. Rev. D61 (2000) 071501
M. Fischer, J.G. Körner, M.C. Mauser and S. Groote
(MZ-TH / 99-27):
"Inclusive decays of B mesons into D_s and D^* and D_s^* at O(alpha_s)
including D_s^* polarization effects",
Phys. Lett. 480 B (2000) 265-272
S. Groote and J. Shigemitsu
(MZ-TH / 99-64):
"One-loop self energy and renormalization of the speed of light for some
anisotropic inproved quark actions",
Phys. Rev. D62 (2000) 014508
S. Groote and A.A. Pivovarov
(MZ-TH / 00-07):
"Threshold expansion of Feynman diagrams within a configuration space
technique", Nucl. Phys. B580 (2000) 459-484
J.G. Körner and S. Groote
(MZ-TH / 00-08):
"Theory of Heavy Baryon Decay",
Invited talk given by J.G. Körner at the 3rd International Conference on B
Physics and CP Violation (BCONF99), Taipei, Taiwan, 3-7 Dec 1999, to appear in
the Proceedings, edited by H.Y. Cheng and W.S. Hou (World Scientific, 2000).
Stefan Groote
(MZ-TH / 00-24):
"QCD sum rules as applied to heavy baryons", Proceedings of the 5th
International Conference on "Heavy Quark Physics", Dubna, Russia, April 6-8,
2000, p.26-30
S. Groote and O.I. Yakovlev
(MZ-TH / 00-33, CLNS / 00-1686):
"Top quark mass definition and t anti-t production near threshold at the NLC",
Phys. Rev. D63 (2001) 074012
S. Groote and O.I. Yakovlev
(MZ-TH / 00-36):
"A dynamic mass definition near the t anti-t threshold", talk given by Stefan
Groote at the Laboratory of Nuclear Studies, Cornell Univ., Ithaca, N.Y.,
23 Aug 2000
O.I. Yakovlev and S. Groote
(MZ-TH / 00-38, CLNS / 00-1690):
"Top quark production near threshold at NLC", talk given by Oleg Yakovlev at
PHENO 2000: Symposium on Phenomenology for the Nu Century, Madison, Wisconsin,
17-19 Apr 2000
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 00-41, CLNS / 00-1693):
"Analytical calculation of heavy baryon correlators in NLO of perturbative
QCD", contribution to the "VII International Workshop on Advanced Computing
and Analysis Techniques in Physics Research (ACAT2000)", Fermi National
Laboratory, Batavia, Illinois, USA, 16-20 Oct 2000, to appear in the
Proceedings
S. Groote, J.G. Körner and J.A. Leyva
(MZ-TH / 00-41, CLNS / 00-1693):
"O(alpha_s) corrections to the polar angle dependence of the longitudinal
spin-spin correlation asymmetry in electron + positron -> quark + anti-quark"
M. Fischer, S. Groote, J.G. Körner and M.C. Mauser
(MZ-TH / 00-50):
"Longitudinal, transverse plus and transverse minus W bosons in unpolarized
top quark decays at O(alpha_s)", Phys. Rev. D63 (2001) 031501
O.I. Yakovlev and S. Groote
(MZ-TH / 00-57, MCTP-00-10):
"On top anti-top threshold and top quark mass definition", talk given by
Oleg Yakovlev on the Linear Collider Workshop 2000, Fermilab, October 2000,
to appear in the Proceedings
M. Fischer, S. Groote, J.G. Körner and M.C. Mauser
(MZ-TH / 99-10):
"Complete angular analysis of polarized top decay at O(alpha_s)",
Phys. Rev. D65 (2002) 054036
S. Groote and A.A. Pivovarov
(MZ-TH / 01-06):
"Low-energy gluon contributions to the vacuum polarization of heavy
quarks", JETP Lett. 75 (2002) 221 [Pisma Zh. Eksp. Teor. Fiz. 75 (2002)
267]
S. Groote and A.A. Pivovarov
(MZ-TH / 01-10):
"Heavy quark induced effective action for gauge fields in the
SU(N_c) x U(1) model and the low-energy structure of heavy quark
current correlators", Eur. Phys. J. C21 (2001) 133-143
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 01-15):
"Spectral moments of two-point correlators in perturbation theory and
beyond", Phys. Rev. D65 (2002) 036001
M. Fischler et al. (FERMILAB-CONF-01-237-T):
Summaries of recent computer-assisted Feynman diagram calculations", prepared
for the 7th International Workshop on Advanced Computing and Analysis
Techniques in Physics Research (ACAT 2000), Batavia, Illinois, 16-20 Oct 2000
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 01-31):
"An interpolation of the vacuum polarization function for the evaluation of
hadronic contributions to the muon anomalous magnetic moment", Eur. Phys. J.
C24 (2002) 393-405
M. Fischer, S. Groote, J.G. Körner and M.C. Mauser
(MZ-TH / 02-03):
"Leptonic mu and tau decays: mass effects, polarization effects and O(alpha)
radiative corrections",
Phys. Rev. D67 (2003) 067311
H.S. Do, S. Groote, J.G. Körner and M.C. Mauser
(MZ-TH / 01-03):
"Electroweak and finite width corrections to top quark decays into
transverse and longitudinal W-bosons", Phys. Rev. D67 (2003) 091501
S. Groote
(MZ-TH / 02-29):
"Polarization effects in e+ e- annihilation processes"
S. Groote
(MZ-TH / 02-30):
"The electron-positron annihilation cross section used for high precision
tests of the Standard Model"
S. Groote
(MZ-TH / 03-10):
"Lectures on configuration space methods for sunrise-type diagrams",
invited lecture series given at the International Research Workshop
"Calculations for Modern and Future Colliders
(Calc2003)", June 13-21, 2003, Dubna, Russia
M. Fischer, S. Groote, J.G. Körner and M.C. Mauser
(MZ-TH / 03-06):
"Semi-inclusive decays Lambda_b -> X_c + D_s^* at O(alpha_s) including
Lambda_b and D_s^* polarization effects", Phys. Rev. D70 (2004) 094026
S. Groote, J.G. Körner and J. Maul
(MZ-TH / 03-14):
"QCD improved determination of the hadronic contribution to the anomalous
magnetic moment of the muon"
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 04-03):
"Laurent series expansion of sunrise-type diagrams using configuration space
techniques", Eur. Phys. J. C36 (2004) 471-482
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 05-08):
"On the evaluation of a certain class of Feynman diagrams in x-space:
Sunrise-type topologies at any loop order",
Annals of Physics (2007)
S. Groote, W.S. Huo, A. Kadeer and J.G. Körner
(MZ-TH / 05-13):
"Azimuthal correlation between the (p_l,p_Xb) and (p_l,P_t) planes in the
semileptonic rest frame decay of a polarized top quark: An O(alpha_s)
effect"
S. Groote, M. Knodel
(MZ-TH / 05-17):
"Evaluating massive planar two-loop tensor vertex integrals",
Eur. Phys. J. C46 (2006) 157-178
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 06-06):
"Large next-to-leading order QCD corrections to pentaquark sum rules",
Phys. Rev. D74 (2006) 017503
S. Groote and C. Beck
(MZ-TH / 06-07):
"Scaling behavior of non-hyperbolic coupled map lattices",
Phys. Rev. E74 (2006) 046216
S. Groote and C. Beck
(MZ-TH / 06-09):
"Scaling properties of invariant densities of coupled Chebyshev maps",
Dyn. Sys. 22(2) (2007) 219-248
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 07-20):
"Next-to-Leading Order perturbative QCD corrections to baryon correlators in
matter", Phys. Rev. D78(3) (2008) 034039
S. Groote, J.G. Körner and A.A. Pivovarov
(MZ-TH / 07-21):
"Heavy baryon properties with NLO accuracy in perturbative QCD",
Eur. Phys. J. C58(3) (2008) 355-382
S. Groote and H. Veermäe
(MZ-TH / 08-11):
"Short chaotic strings and their behaviour in the scaling region",
Chaos, Solitons and Fractals 41(5) (2005) 2354-2359
S. Groote and J.G. Körner
(MZ-TH / 98-23, superseded by MZ-TH / 08-39):
"Analytical results for O(alpha_s) radiative corrections to
electron-positron annihilation into antitop and polarized top up to a given
energy cut", Phys. Rev. D80(3) (2009) 034001
S. Groote, J.G. Körner and J.A. Leyva,
(MZ-TH / 00-49, superseded by MZ-TH / 09-18):
"O(alpha_s) corrections to the polar angle dependence of the longitudinal
spin-spin correlation asymmetry in e^+ e^- -> q q-bar",
Eur. Phys. J. C63(3) (2009) 391-406
S. Groote, H. Liivat, I. Ots and T. Sepp,
(MZ-TH / 09-29):
"Probing scalar particle and unparticle couplings in e+ e- -> t tbar with
transversely polarized beams", Eur. Phys. J. C66(1) (2010) 271-281
S. Groote, J.G. Körner,
(MZ-TH / 09-42):
"O(alpha(s)) spin effects in e+ e- ---> q anti-q (g)",
to appear in the Proceedings of 13th Workshop on High Energy Spin Physics
(DSPIN-09), Dubna, Moscow Region, Russia, 1-5 Sep 2009
R. Saar, S. Groote, H. Liivat and I. Ots,
(MZ-TH / 10-20):
"Gauge and Lorentz transformation placed on the same foundation",
Adv. Math. Phys. 2011 (2011) 652126
S. Groote, H. Liivat and I. Ots,
(MZ-TH / 10-29):
"Symmetries and similarities for spin orientation parameters in
e^+ e^- -> ZH, Z\gamma, ZZ at SM thresholds",
Nucl. Phys. B843 (2011) 213-222
S. Groote, J.G. Körner, B. Melić and S. Prelovsek,
(MZ-TH / 10-47):
"A survey of top quark polarization at a polarized linear e^+ e^- collider",
Phys. Rev. D83 (2011) 054018
R. Saar, S. Groote, H. Liivat and I. Ots,
(MZ-TH / 09-30):
"`Dynamical' interactions and gauge invariance",
Phys. Rev. D84(6) (2011) 065022
S. Groote, J.G. Körner and A.A. Pivovarov,
(MZ-TH / 11-17):
"Calculation loops without loop calculations: NLO computation of pentaquark
correlators",
Phys. Rev. D86(3) (2012) 034023
S. Groote and J.G. Körner,
(MZ-TH / 11-45):
"Quark polarization at a polarized linear e^+ e^- collider",
to appear in the proceedings of the conference
DSPIN-11, Dubna, Russia, Sept 20-24, 2011
S. Groote, J.G. Körner and A.A. Pivovarov,
(MZ-TH / 12-15):
"A numerical test of differential equations for one- and two-loop sunrise
diagrams using configuration space techniques",
Eur. Phys. J. C72(7) (2012) 2085
S. Groote, J.G. Körner and P. Tuvike,
(MZ-TH / 12-16):
"O(alpha_s) corrections to the decays of polarized W^+- and Z bosons into
massive quark pairs",
Eur. Phys. J. C72(10) (2012) 2177
S. Groote, H. Veermäe and C. Beck,
(MZ-TH / 12-35):
"Renormalization group approach to chaotic strings",
submitted for publication in "Chaos, Solitons & Fractals"
S. Groote, J.G. Körner, B. Melić and S. Prelovsek,
(MZ-TH / 12-41):
"Single top quark polarization at O(alpha_s) in t t-bar production at a
polarized linear e^+ e^- collider", extended version of a talk given at the
LC Forum Munich 2011, to be published as a DESY-123 LC review report and in
EPJC
S. Groote, J.G. Körner and A.A. Pivovarov,
(MZ-TH / 12-53):
"Understanding perturbative results for decays of tau leptons into hadrons",
contribution to the Festschrift published on the occasion of the 60th
birthday of Dmitri Kazakov
S. Groote, J.G. Körner and P. Tuvike,
(MZ-TH / 12-55):
"Fully analytical O(alpha_s) results for on-shell and off-shell polarized
W-boson decays into massive quark pairs",
submitted for publication in Eur. Phys. J. C
I love Hagen, the town I am born in 1963, although visitors told me that it is ugly and not as representative as other towns in the Ruhrgebiet like e.g. Dortmund, my former place of studies. To give you a small insight in my town, I display a picture of our townhall, only twenty years old. I have painted it for the "Kirchentag im Ruhrgebiet" in 1991, when tenthousands of children came to Hagen to see the Musical "Zack" there. Because of this favour for my town I frequently use the Deutsche Bahn to get from here to there. But on holidays, my favorite country is Sweden or Sverige. After my engagement with Edith Vohu from Tartu on August 12th, 2001, or registration on August 13th, 2003, the birth of our daughter Linda-Reet on January 24th, 2004 and Ediths and my marriage on August 28th, 2004 you will find us more or less in Estonia. On January 1st, 2006 our second daughter Elo-Maarja was born. So be aware to meet me in Tartu (earlier name: Dorpat) at Tartu Ülikoolil!
My hobbies are the following:
© by Stefan Groote, 9.01.2013