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Dark-matter production through loop-induced processes at the LHC: the s-channel mediator case.

Mattelaer O, Vryonidou E - Eur Phys J C Part Fields (2015)

Bottom Line: We show how studies relevant for mono-X searches at the LHC in simplified models featuring a dark-matter candidate and an s-channel mediator can be performed within the MadGraph5_aMC@NLO framework.We focus on gluon-initiated loop-induced processes, mostly relevant to the case where the mediator couples preferentially to third generation quarks and in particular to the top quark.Our implementation allows us to study signatures at hadron colliders involving missing transverse energy plus jets or plus neutral bosons ([Formula: see text]), possibly including the effects of extra radiation by multi-parton merging and matching to the parton shower.

View Article: PubMed Central - PubMed

Affiliation: Institute for Particle Physics Phenomenology (IPPP), Durham University, Durham, DH1 3LF UK.

ABSTRACT

We show how studies relevant for mono-X searches at the LHC in simplified models featuring a dark-matter candidate and an s-channel mediator can be performed within the MadGraph5_aMC@NLO framework. We focus on gluon-initiated loop-induced processes, mostly relevant to the case where the mediator couples preferentially to third generation quarks and in particular to the top quark. Our implementation allows us to study signatures at hadron colliders involving missing transverse energy plus jets or plus neutral bosons ([Formula: see text]), possibly including the effects of extra radiation by multi-parton merging and matching to the parton shower.

No MeSH data available.


Missing  distribution for  for the vector (V) and axial-vector (A) mediators
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Fig18: Missing distribution for for the vector (V) and axial-vector (A) mediators

Mentions: The normalised parton-level missing transverse momentum distributions, i.e. the transverse momentum of the mediator, for the four types of mediator couplings are shown in Figs. 17 and 18. Again the resonant scenario gives a distribution which falls more rapidly, and we find that the shape of the distributions are the same for the scalar and pseudoscalar mediators. These shapes are similar to those given by the box contribution to the production is the SM, as shown in [25]. In the SM, though, there is a significant, nearly exact at high , cancellation between the box and triangle diagrams, which leads to suppressed tails. This cancellation is absent in the DM scenarios, and the distributions fall very slowly. We note that the total cross section for the resonant case is smaller than the SM one, even though the masses () are similar, as it is the triangle contribution that is the dominant one in the SM at low energies.Fig. 18


Dark-matter production through loop-induced processes at the LHC: the s-channel mediator case.

Mattelaer O, Vryonidou E - Eur Phys J C Part Fields (2015)

Missing  distribution for  for the vector (V) and axial-vector (A) mediators
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581402&req=5

Fig18: Missing distribution for for the vector (V) and axial-vector (A) mediators
Mentions: The normalised parton-level missing transverse momentum distributions, i.e. the transverse momentum of the mediator, for the four types of mediator couplings are shown in Figs. 17 and 18. Again the resonant scenario gives a distribution which falls more rapidly, and we find that the shape of the distributions are the same for the scalar and pseudoscalar mediators. These shapes are similar to those given by the box contribution to the production is the SM, as shown in [25]. In the SM, though, there is a significant, nearly exact at high , cancellation between the box and triangle diagrams, which leads to suppressed tails. This cancellation is absent in the DM scenarios, and the distributions fall very slowly. We note that the total cross section for the resonant case is smaller than the SM one, even though the masses () are similar, as it is the triangle contribution that is the dominant one in the SM at low energies.Fig. 18

Bottom Line: We show how studies relevant for mono-X searches at the LHC in simplified models featuring a dark-matter candidate and an s-channel mediator can be performed within the MadGraph5_aMC@NLO framework.We focus on gluon-initiated loop-induced processes, mostly relevant to the case where the mediator couples preferentially to third generation quarks and in particular to the top quark.Our implementation allows us to study signatures at hadron colliders involving missing transverse energy plus jets or plus neutral bosons ([Formula: see text]), possibly including the effects of extra radiation by multi-parton merging and matching to the parton shower.

View Article: PubMed Central - PubMed

Affiliation: Institute for Particle Physics Phenomenology (IPPP), Durham University, Durham, DH1 3LF UK.

ABSTRACT

We show how studies relevant for mono-X searches at the LHC in simplified models featuring a dark-matter candidate and an s-channel mediator can be performed within the MadGraph5_aMC@NLO framework. We focus on gluon-initiated loop-induced processes, mostly relevant to the case where the mediator couples preferentially to third generation quarks and in particular to the top quark. Our implementation allows us to study signatures at hadron colliders involving missing transverse energy plus jets or plus neutral bosons ([Formula: see text]), possibly including the effects of extra radiation by multi-parton merging and matching to the parton shower.

No MeSH data available.