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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.


Invariant mass distribution for the DM pair  jets for a vector mediator
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Fig12: Invariant mass distribution for the DM pair jets for a vector mediator

Mentions: Following the same procedure, one can obtain results for the vector and axial-vector mediators. When merging samples of different multiplicities, one needs to take into account that for a vector mediator, the 0-jet contribution is zero due to Landau–Yang theorem [40, 41]. The quark–gluon-initiated contributions to the 1-jet process also vanish. In fact, any diagram involving a triangle with two gluons and a vector mediator as the external legs vanishes, due to charge conjugation invariance. Therefore, in the vector case, we only merge the 1 and 2-jet contributions. For numerical stability we have removed the triangle diagrams at the time of generation of the code. The differential distributions are shown in Figs. 10, 11 and 12.


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)

Invariant mass distribution for the DM pair  jets for a vector mediator
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig12: Invariant mass distribution for the DM pair jets for a vector mediator
Mentions: Following the same procedure, one can obtain results for the vector and axial-vector mediators. When merging samples of different multiplicities, one needs to take into account that for a vector mediator, the 0-jet contribution is zero due to Landau–Yang theorem [40, 41]. The quark–gluon-initiated contributions to the 1-jet process also vanish. In fact, any diagram involving a triangle with two gluons and a vector mediator as the external legs vanishes, due to charge conjugation invariance. Therefore, in the vector case, we only merge the 1 and 2-jet contributions. For numerical stability we have removed the triangle diagrams at the time of generation of the code. The differential distributions are shown in Figs. 10, 11 and 12.

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.