Post-doctoral researcher in QCD scattering amplitudes (M/F)

Job Description

Missions

The post-doctoral researcher will join the theory pole of IJCLab to work on multi-loop amplitudes relevant for higher-order QCD corrections. While the leading order (LO) cross-section constitutes the bulk of the observable, next-to-leading order (NLO) terms in the expansion of the strong coupling constant can induce large corrections. For many collider observables, NLO cross-sections are routinely used in phenomenological studies. However, with the upcoming high-luminosity phase of the LHC and the improved experimental data, the theory predictions have to be equally extended to higher orders to match their precision. In this context, next-to-next-to-leading order (NNLO) corrections are indispensable for phenomenology. An important ingredient are the two-loop amplitudes that involves the non-trivial calculation of two-loop Feynman integrals.

Activity

In the first step, the post-doctoral fellow will compute the scattering amplitudes and express the form-factors as a linear combination of master integrals which will be achieved via usage of the Integration-By-Parts (IBP) technique. In the second step, the fellow will compute the master integrals that constitute the building blocks of Feynman integrals using different techniques, e.g. with the differential equation approach. The efficient evaluation of integrals requires a suitable basis of master integrals to avoid the appearance of spurious singularities. Several cross-checks will be performed at several different phase-space points using alternative methods. In the third step, the fellow will perform phenomenological NNLO studies to compare theory predictions with experimental data and perform an assessment of the scale uncertainties. Several visits to conferences and workshops are foreseen in order to promote the results of the project.

Your Profil

Skills

The candidate has to hold a PhD degree in the area of theoretical physics by the start date of the position. They should have good prior experience with computing and automating the evaluation of multi-loop scattering amplitudes and integrals. The candidate must be able to promote research through publications and oral presentations at conferences and workshops. For this, several travel trips are foreseen. In addition, the candidate must be fluent in English, and they must be able to work in a team.

Your Work Environment

The Irène Joliot-Curie Physics Laboratory of 2 Infinities (IJCLab) is a joint laboratory between a university and a public research institution under the supervision of the CNRS (IN2P3), the University of Paris-Saclay and the University of Paris is located on the campus of the University of Paris-Saclay in Orsay. The campus is located 20 km south of Paris and easily accessible by RER in 35 minutes.
IJCLab was born in 2020 from the merger of five units (CSNSM, IMNC, IPN, LAL, LPT). The staff is made up of nearly 560 permanent (340 engineers, technicians and administrators and 220 researchers and teacher-researchers) and approximately 200 non-permanent including 120 doctoral students. The research themes of the laboratory are nuclear physics, high energy physics, theoretical physics, astroparticles, astrophysics and cosmology, particle accelerators, energy and the environment and health. IJCLab has very significant technical capacities (around 280 IT) in all the major fields required to design, develop / implement the experimental devices necessary for its scientific activity, as well as the design, development and use of instruments.
The candidate will join the group of M.A. Ozcelik in the theory pole who leads this project.

Constraints and risks

Short periods of travel within France and abroad should be expected.
Submit a cover letter, a research statement and a CV without any break in date showing diplomas, titles and work and professional experience. In addition, two recommendation letters by senior colleagues are required.

Compensation and benefits

Compensation

From 3131,32 euros to 4341,70 euros gross per month depending on experience

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

The research professions