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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.


Hardest and second hardest jet transverse momentum distribution for  jets for a scalar mediator
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Fig3: Hardest and second hardest jet transverse momentum distribution for jets for a scalar mediator

Mentions: The normalised distributions for the hardest, second hardest jet and the missing transverse momentum for the three scenarios are shown in Figs. 3 and 4, respectively. The invariant mass distributions of the DM pair for the various benchmarks are presented in Fig. 5. The resonant curve displays a sharp resonant peak, while the heavy-mediator scenario has an important tail at low invariant masses, with the off-shell region contributing significantly to the cross section. In both curves a threshold effect can be observed at when the top quarks running in the loop become on-shell. We note that the mass of 1 TeV for the mediator is not sufficiently high for the EFT approach to be valid as the mass of the mediator is probed, as shown clearly in Fig.  5. For the third and final scenario – heavy DM – the production threshold lies above the mediator mass and therefore no resonant structure arises.


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)

Hardest and second hardest jet transverse momentum distribution for  jets for a scalar mediator
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig3: Hardest and second hardest jet transverse momentum distribution for jets for a scalar mediator
Mentions: The normalised distributions for the hardest, second hardest jet and the missing transverse momentum for the three scenarios are shown in Figs. 3 and 4, respectively. The invariant mass distributions of the DM pair for the various benchmarks are presented in Fig. 5. The resonant curve displays a sharp resonant peak, while the heavy-mediator scenario has an important tail at low invariant masses, with the off-shell region contributing significantly to the cross section. In both curves a threshold effect can be observed at when the top quarks running in the loop become on-shell. We note that the mass of 1 TeV for the mediator is not sufficiently high for the EFT approach to be valid as the mass of the mediator is probed, as shown clearly in Fig.  5. For the third and final scenario – heavy DM – the production threshold lies above the mediator mass and therefore no resonant structure arises.

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.