Experiments:CMS collaboration at LHC
Deadline: 2016-05-22
Region: Europe
Job description:
The CMS-group of the IPHC Strasbourg is seeking candidates for a PHD thesis starting in October 2016 for three years on the subject
“Search for Super Symmetry in the Higgs sector »
The thesis should explore the NMSSM at the LHC at 13 TeV, The thesis is in the first place an experimental (=analysis) thesis, however with a “phenomenological” component.
The potential PhD-candidate for this thesis should have good marks for his Master studies (first year and first semester of the second year) in order to be preselected before the end of May for an interview in June at the “école doctorale”, which will decide whether or not a grant is available for this PhD thesis and the student.
Search for Super Symmetry in the Higgs sector
DIRECTEUR DE THESE : ULRICH GOERLACH
INSTITUT PLURIDISCIPLINAIRE HUBERT CURIEN (IPHC) ;
23 RUE DU LOESS, BP 28 – 67037 STRASBOURG CEDEX 2
TELEPHONE : 03 88 10 66 44 ; FAX : 03 88 10 62 34
EMAIL : ULRICH.GOERLACH@IPHC.CNRS.FR
The first years of the LHC running have lead the discovery of the Higgs boson with properties
very close to those predicted for a Higgs boson of the Standard Model (SM). At the same
time numerous searches for physics beyond the Standard Model (BSM) have been
performed, particular for Super Symmetry (SUSY), the most popular and best-motivated
possible extension of the SM. No supersymmetric particle has been discovered so far and
the possible mass scale for such particles seems now to be close to one TeV, possibly
accessible in the present Run of the LHC with a higher centre of mass energy of 13 TeV.
Besides the existence of new particles, Super Symmetry predicts a significant modification of
the Higgs sector: The simplest realization, the Minimal Supersymmetric Standard Model
(MSSM), adds one more neutral CP-even Higgs boson, one CP-odd Higgs boson and a pair
of charged Higgs bosons to the Standard Model Higgs. In other extensions, for example the
Next to Minimal Supersymmetric Standard Model (NMSSM), there will be more neutral
bosons, three neutral scalars and two neutral pseudo-scalars. Depending on their respective
masses it will be possible to study Higgs-Higgs interactions by decays of one Higgs boson to
another one, giving new and often spectacular signatures (see for example
arXiv:1408.1120v1).
The Run of the LHC, which has started this year with high luminosity at a centre of mass
energy of 13 TeV will allow probing these extensions of the Higgs sector with different search
channels and analysis strategies. This will be the central subject of the thesis proposed here.
The PhD thesis, which could be preceded by a Master thesis in Spring 2016, will be carried
out at the IPHC, Strasbourg within the group working on the CMS experiment at the LHC.
The thesis will start in October 2016 with an analysis based on a phenomenological
feasibility study (Monte-Carlo simulation level, work in progress) having identified one or two
of the most promising search channels for such a non-standard Higgs boson and having
evaluated its discovery potential for the new LHC data at 13 TeV. The experimental
signatures and challenges in the analysis will be tau-lepton and b-jet identification or low
momentum photons: we will look at final states like “ bb +ττ +γγ ” Such signatures are also
typical for double Higgs production of the Standard Model. The CMS group in Strasbourg is
the leading team in CMS working on b-jet recognition and has also important knowledge on
tau-identification. The data analysis and the corresponding programmes will be developed in
the context of the CMS collaboration, especially within the Higgs-working groups.
Collaborating with other CMS groups (Lyon, Paris and others) will also be necessary. Close
contacts with theoretical physicists in France (GDR Terascale network) and in Germany
(KIT), specialists of the NMSSM, are foreseen in order to work towards a discovery of Super
Symmetry in the Higgs sector. In the absence of a discovery we will be able to place strong
limits on parts of the SUSY parameter space within the framework of the NMSSM or for
SUSY in general.
The PhD candidate should have an excellent academic record and knowledge in
programming (C++ and Root). Further she/he should have the necessary communication
skills to work across the international CMS collaboration.
More Information:http://www.iphc.cnrs.fr/-CMS-.html