Quantum field theory; Perturbation theory; Elementary particles; Collider physics
Gehrmann-De Ridder A., Gehrmann T., Glover E. W. N., Huss A., Morgan T. A. (2016), Precise QCD predictions for the production of a Z boson in association with a hadronic jet, in
Phys. Rev. Lett., 117(2), 022001-022001.
Anastasiou Charalampos, Duhr Claude, Dulat Falko, Furlan Elisabetta, Gehrmann Thomas, Herzog Franz, Mistlberger Bernhard (2015), Higgs boson gluon-fusion production beyond threshold in N$^{3}$LO QCD, in
JHEP, 03, 091-091.
Wiesemann M., Frederix R., Frixione S., Hirschi V., Maltoni F., Torrielli P. (2015), Higgs production in association with bottom quarks, in
JHEP, 02, 132-132.
Chen X., Gehrmann T., Glover E. W. N., Jaquier M. (2015), Precise QCD predictions for the production of Higgs + jet final states, in
Phys. Lett., B740, 147-150.
Gehrmann Thomas, Guns Sam, Kara Dominik (2015), The rare decay $H\to Zγ$ in perturbative QCD, in
JHEP, 09, 038-038.
Gehrmann Thomas, von Manteuffel Andreas, Tancredi Lorenzo (2015), The two-loop helicity amplitudes for $ qøverlineq^{\prime}\to V_1V_2\to 4 $ leptons, in
JHEP, 09, 128-128.
Duhr Claude, Gehrmann Thomas, Jaquier Matthieu (2015), Two-loop splitting amplitudes and the single-real contribution to inclusive Higgs production at N$^3$LO, in
JHEP, 02, 077-077.
Gehrmann T., Grazzini M., Kallweit S., Maierhöfer P., von Manteuffel A., Pozzorini S., Rathlev D., Tancredi L. (2014), $W^+W^-$ Production at Hadron Colliders in Next to Next to Leading Order QCD, in
Phys. Rev. Lett., 113(21), 212001-212001.
Gehrmann Thomas, Häfliger Niklaus, Monni Pier Francesco (2014), BLM Scale Fixing in Event Shape Distributions, in
Eur. Phys. J., C74(6), 2896-2896.
Gehrmann-De Ridder A., Gehrmann T., Glover E. W. N., Heinrich G. (2014), EERAD3: Event shapes and jet rates in electron-positron annihilation at order $α_s^3$, in
Comput. Phys. Commun., 185, 3331-3331.
Anastasiou Charalampos, Duhr Claude, Dulat Falko, Furlan Elisabetta, Gehrmann Thomas, Herzog Franz, Mistlberger Bernhard (2014), Higgs boson gluon–fusion production at threshold in N$^3$LO QCD, in
Phys. Lett., B737, 325-328.
Maierhöfer Philipp, Papaefstathiou Andreas (2014), Higgs Boson pair production merged to one jet, in
JHEP, 03, 126-126.
Papaefstathiou Andreas, Sakurai Kazuki, Takeuchi Michihisa (2014), Higgs boson to di-tau channel in Chargino-Neutralino searches at the LHC, in
JHEP, 08, 176-176.
Frederix R., Frixione S., Hirschi V., Maltoni F., Mattelaer O., Torrielli P., Vryonidou E., Zaro M. (2014), Higgs pair production at the LHC with NLO and parton-shower effects, in
Phys. Lett., B732, 142-149.
Auge Etienne (ed.) (2014),
QCD and High Energy Interactions: Moriond 2014 Theory Summary, Editions Arisf, Merignac.
Currie James, Gehrmann-De Ridder Aude, Gehrmann Thomas, Glover Nigel, Pires Joao, Wells Steven (2014), Second order QCD corrections to gluonic jet production at hadron colliders, in
PoS, LL2014, 001-001.
Ferreira de Lima Danilo Enoque, Papaefstathiou Andreas, Spannowsky Michael (2014), Standard model Higgs boson pair production in the ( $ bøverlineb $ )( $ bøverlineb $ ) final state, in
JHEP, 08, 030-030.
Gehrmann Thomas, Kara Dominik (2014), The $Hb\barb$ form factor to three loops in QCD, in
JHEP, 09, 174-174.
Alwall J., Frederix R., Frixione S., Hirschi V., Maltoni F., Mattelaer O., Shao H. -S., Stelzer T., Torrielli P., Zaro M. (2014), The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations, in
JHEP, 07, 079-079.
Gehrmann Thomas, von Manteuffel Andreas, Tancredi Lorenzo, Weihs Erich (2014), The two-loop master integrals for $qøverlineq \to VV$, in
JHEP, 06, 032-032.
Cascioli F., Gehrmann T., Grazzini M., Kallweit S., Maierhöfer P., von Manteuffel A., Pozzorini S., Rathlev D., Tancredi L., Weihs E. (2014), ZZ production at hadron colliders in NNLO QCD, in
Phys. Lett., B735, 311-313.
Jet cross sections and multi-particle production are among the most important observables studied at current and future experiments in high energy physics. Their measurement enables the determination of fundamental parameters of the theory of strong interactions. The theoretical description of these observables was up to very recently restricted to the next-to-leading order in perturbation theory; the resulting theoretical uncertainty is by now insufficient to match the current experimental precision. The proposed project aims to develop new methods for the calculation of jet and multi-particle cross sections in higher orders of perturbation theory, and to apply these methods in actual computations. The computation of higher orders in perturbation theory goes through the evaluation of all field theoretic subprocesses contributing to the observable under consideration. Although the sum of all these subprocesses yields a finite result for suitably defined observables, individual subprocesses contain infinities due to the exchange of low-momentum particles (infrared singularities) or high-momentum particles (ultraviolet singularities). In general, the presence of these singularities forbids a direct numerical evaluation of higher order corrections. To compute jet observables in higher perturbative orders, one has to devise procedures to analytically extract especially the infrared singularities from each subprocess. Only after carrying out this infrared separation, it is possible to add together different subprocesses in order to obtain predictions for experimentally measured jet observables, which is made using a flexible numerical programme, a so-called parton level event generator. The current state of the art in the theoretical description of jet observables are calculations to the next-to-leading order (NLO) in perturbation theory. Calculations of jet observables at NNLO are at present available only for three-jet production in electron-positron collisions. Proof-of-principle implementations of NNLO corrections for jet observables at hadron colliders have been performed most recently. The project proposed here aims to contribute to the following aspects of precision physics at high energy particle colliders: (a) development of NNLO parton-level event generator programs for jet production and for Higgs-boson-plus-jet production in hadron-hadron collisions; (b) computation of mass corrections in Higgs-boson-plus-jet production to NLO; (c) preparatory studies towards two-loop QCD corrections to 2 -> 3 scattering processes; (d) development of modern event simulation programs for multi-particle final states and improvements to the parton shower formalism.