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Propositions de stage ou thèse au LPTHE
Stage/Doctorat en physique théorique des hautes énergies
Directeur: Karim Benakli
Nous recherchons un(e) étudiant(e) de Master-2 avec une formation en physique théorique des hautes énergies intéressé(e) par l'un des trois sujets suivants, à discuter pour convenir d'un choix avec l'étudiant(e):
1) Les modèles de brisure de supersymétrie : la supersymétrie, une symétrie ayant plusieurs vertus pour les théories au-delà du Modèle Standard, n'est pas observée expérimentalement, elle doit donc être brisée si elle joue un rôle dans la nature.
2) La conjecture de la gravité faible : cette conjecture affirme que pour toute théorie de jauge abélienne, il existe un état pour lequel la force gravitationnelle (Newton) est plus faible que l'interaction de jauge (Coulomb).
3) L'étude des équations de mouvement décrivant la propagation des particules dans des milieux non triviaux. En particulier, pour les particules de spin > 1, la description de la propagation des modes d'hélicité longitudinale présente des propriétés intéressantes et nécessite une analyse particulière.
Un doctorat en physique théorique des hautes énergies est également possible sur des sujets similaires, sous réserve de la condition habituelle de réussite de la demande de financement par l'Ecole Doctorale.
Contact: Karim Benakli par e-mail à l'adresse kbenakli_AT_lpthe.jussieu.fr
Internship/PhD in Dark Matter theory and phenomenology
Advisor: Marco Cirelli
About 85% of the matter in the Universe is in the form of an unknown substance dubbed Dark Matter (DM). While some of its general properties are known, its actual nature is still undetermined. The most popular hypothesis is that it consists of a new, yet-to-be-discovered elementary particle. One of the possible strategies to investigate it is via the so-called Indirect Detection (ID): studying the possible excesses in cosmic rays that could produced by the annihilations (or decays) of DM particles in the galactic halo, and comparing them with the theoretical predictions from particle physics models.
Within this broad context, the proposed Master 2 internship (and the possible ensuing PhD project) will proceed in different directions: X-rays, velocity-dependent annihilations, primordial black holes constraints, synchrotron bounds, purely gravitational effects... (to be decided according to the interests and the opportunities).
Following the typical course, after the Master 2 internship lasting a few months during Spring 2024 and subject to mutual agreement, the student can then apply for a PhD fellowship (from EDPIF or from other sources) and, if successful, start the PhD in Fall 2024, for a duration of 3 years.
Application procedure: Candidates should send by email to marco.cirelli_AT_gmail.com: i. their CV, ii. a transcript of their academic records, iii. a short description of their interests (optional, and in any case no longer than 1 page). iv. They should also arrange for 1 or 2 short letters of recommendation to be sent to the same address, by scientists familiar with their studies and academic record.
Applications are preferred within December 31st, 2023, but will be considered afterwards if the position is not filled. Short-listed candidates will be invited for a meeting, either in person or remotely.
Internship/PhD on Precision predictions for four-top production at the LHC
Advisors: Benjamin Fuks and Hua-Sheng Shao
The Standard Model of particle physics is an extremely successful theory whose predictions match data to an excellent extent. Despite this success, the current experimental status reveals several of its conceptual and practical limitations, like the absence of a candidate for dark matter, the hierarchy problem or the problematics of neutrino masses. The Standard Model is therefore acknowledged as an effective theory that should originate from a more fundamental one yet to be discovered, and new phenomena are expected at energies well below the Planck scale. One interesting avenue in the searches for new physics relies on probes involving the comparison of precision theoretical predictions to accurate experimental measurements.
By far and large, this currently means making use of matrix elements computed to (at least) the next-to-leading-order accuracy and possibly matched with the resummation of threshold logarithms. The latter consists of an attempt to quantify the effects of a well-defined set of corrections to all orders of perturbation theory, with the aim of reducing the theory error bars (so that meaningful comparisons with experimental data could be achieved). In recent years, we have developed a numerical program achieving resummed predictions for four-top production at hadron colliders. The choice to focus on such a process is driven by the fact that among all measurements to be made at the currently on-going LHC Run 3, those related to four-top production will be performed for the first time with enough precision for being compared with theoretical predictions. It is therefore critical to provide precise theoretical predictions. The proposed internship aims to make use of the program that has been developed at LPTHE, understand the underlying concepts (inherent to the theory of the strong interaction, i.e. QCD) and improve its efficiency so that it could be shared with the high-energy physics community as a whole.
After the M2 internship that is expected to last a few months in Spring 2024 and subject to mutual agreement, the candidate will then apply for a PhD fellowship (from EDPIF or other sources) to start in Fall 2024 and for a duration of three years.
Application procedure
Candidates familiar with computer programming languages like C/C++ are particularly encouraged to apply.
Candidates should send by email to fuks_AT_lpthe.jussieu.fr and huasheng.shao_AT_lpthe.jussieu.fr their CV, a transcript of their academic records (M1 + L3 + existing M2 results if any) and a short motivation letter (optional and no longer than one page). They should also arrange for one or two letters of recommendation to be sent to the same addresses, by scientists familiar with their studies and academic records.
Applications are preferred within 31 st December 2023, but will be considered afterwards if the position is not filled. Short-listed candidates will be invited for a meeting, either in person or remotely.
