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Les Houches

2019 Session

Wikis of Previous sessions

Les Houches Themes



Project Acronym: RDM

Interested people: Benj, Andreas Goudelis, Genevieve Belanger, Dipan Sengupta, Aoife Bharucha, José Zurita, Jose Miguel No, Jordan Bernigaud, Jan Heisig, Giacomo Polesello, Priscilla Pani, Biplob Bhattacherjee, Andre Lessa, Cedric Delaunay, Adil Jueid.

[Feel free to edit tasks!]

Goal (pseudo-ambitious): study the interplay between RD anomalies and Dark Matter.

Goal (concrete): use the S1 leptoquark model that solves RD and RD* and study the dark matter aspect.

Setup: Work in a model with 3 new particles (S1, chi1, chi0) and 3 couplings y^L_{3X}, y^{R}_{23} and y_D. S1 is a scalar leptoquark solving the RD anomalies, chi1 and chi0 are fermions, probably close in mass, with chi0 being a SM singlet, hence chi1 has the same SM gauge charges as S1.

Tasks (updated from 27.06.2019)

0- We will meet on 16.07.2017 at 16:00 CERN time!!!

1- Existing UFO seems to work. AG wants to check the .fr file.

2- Flavor constraints: Marco made a survey of existing bounds. To make a long story short:

a) D-Dbar mixing is suppressed by theta_C^3 and one chirality flip. Gives no meaningful bounds.

b) Bc → tau nu, Z→tau tau (1-loop x EFT) give bounds (computed).

c) Sewing altogether the allowed region can be displayed in the yL23-yR33 plane, with the results that yL < = yR. The scaling with S1 mass is seemingly trivial (to be checked). Plot by Marco will come soon (from Davide). Ref point of mS1=1.5 TeV, yL=1=yR solves the RD anomalies

3) Relic density: from coannihilation, GB says that mchi1=890 and mchi0=800 with yd=1 gives the right relic. Ongoing work (Jan, André, Genevieve) on checking the CDFO.

4) Recasting collider searches: i) Benj wants to set-up the recast of the LQ_res + MET search. ii) Bounds on chi1 come from mono/multi-jet + MET. Some of these were recasted in Fig.7 of 1703.00452 (take the XF3 shaded region), which means that 500-600 GeV were excluded with the ATLAS 13.3 fb-1 search, and that HL-LHC will push the bounds to 1.1 - 1.3 TeV. Bound is almost independent on the compression (mchi1-mchi0). iii) bounds from l + LQ, where LQ → a) tau charm, b) top +tau and c) b nu. Easier to have the charm in the initial state, due to PDF suppression (but b is also possible). Giacomo, José and Jordan will look into existing searches that could give constraints.

5) 1-loop direct detection is under investigation

6) Jordan will set-up a Dropbox folder for the project

Tasks (updated, from 25.06.2019):

1- Expand existing UFO for dark matter: add yD coupling. Make it Micromegas friendly by including tildes for dark particles (see below for details on the model). In charge: Benj,JB, DS

  • FeynRules implementation (v2) + toy mathematica notebook: here.
  • CalcHEP/UFO v2 files: CH and UFO.

2- Check flavor constraints: how much can we relax y^L_{3X}, y^{R}_{23} / mS1^2 = 1/(4 TeV^2)? Interest is to lower mS1 and the couplings as much as possible without colliding with other flavor bounds coming from e.g: D-Dbar mixing (that would apply on combinations of couplings and masses, y^{R}_{23}^2 / mS1^2 ). Persons in charge: MN, JB, AB

3- Monojet bounds on chi1: Assuming that chi1 decays are soft an go undetected, there will be *unavoidable* direct bounds from monojets on the mchi1 mass [Note that in the simplified model chi1 decays 100% into chi0 + SM particles, so there is no branching ratio dillution here). Persons in charge: JZ, DS, AL

4- * NEW *: There will be constraints from gq → l + S1 (also in principle gq → LQ + q + l is possible, but this is suppressed by being a 2→ process instead of a 2→3 one). Persons in charge: GP, AL, JZ

5- Relic density: We will in principle have two possible production freeze-out modes: either co-annihilation (CA) or conversion-driven (CD). Once #1 is solved, this can be investigated with micromegas (CA) or by private Jan's code (CD). Persons in charge: GB, AG, JMN, DS, JH

6- Direct-detection (1-loop induced): This is in principle implemented in Micromegas, so it should be easy to check. Person in charge: GB, AG, DS.

Tasks (from 20.06.2019 meeting):

1- Get a working Lagrangian. From private communication with D. Marzocca we need to have both left handed and right handed couplings to S1. The dark sector includes a chi1 (coloured and charged) and a chi0 (singlet) field. The implementation include LQ couplings to lepton and quark doublets (bL-vL) and LQ couplings to the lepton and quark singlets (cR-tauR). The model finally includes a 3rd coupling (yDM) to the chi1-chi0 pair. Persons in charge: Benjamin, Dipan.

  • A FeynRules implementation is now available and can be downlaoded from here. The tarball contains the SM implementation (, the new physics sector implementation ( and a toy mathematica notebook (use-LQDM.nb).
  • The provided mathematica notebook has been used to generate UFO and CalcHep model files.
  • Here is a note detailing what has been implemented. The TeX version is also available.
  • Important message from Benj: The model still needs to be double-checked by an independent pair of eyes!

2- RD explained by mS1=2 TeV, and both lq couplings being 1. (From D. Marzocca). Anomaly explained by lambda_bv * lambda_ctau / mS1^2.

3- Study bounds from direct detection. These happen at the 1-loop level, expressions known in literature for the SUSY case. In charge: Genevieve, Andreas, Dipan, Jose Miguel.

4- look into CMS search for LQ + MET (motivated by the “Coannihilation Codex”) and for existing searches constraining chi1. In charge: Aoife, José.

5- study relic density (after 1-4 are done). Jan







Zoology of New Physics Models for the Flavour Anomalies

2019/groups/bsm/rdm.txt · Last modified: 2019/06/27 17:19 by jose.zurita