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SUMMARY:One-loop scalar leptoquarks effects in Higgs pair production via g
 luon fusion
DTSTART;VALUE=DATE-TIME:20261023T211000Z
DTEND;VALUE=DATE-TIME:20261023T212000Z
DTSTAMP;VALUE=DATE-TIME:20261110T142048Z
UID:indico-contribution-71@cern.ch
DESCRIPTION:Speakers: Mr. TOSCANO\, Marcelo (Student)\nHiggs pair producti
 on via gluon fusion\, $gg \\to HH$\, probes the Higgs trilinear self-coupl
 ing and is loop-induced already at leading order\, which makes it sensitiv
 e to new colored states. We study the one-loop effects of the scalar lepto
 quark $S_{1} \\sim(\\bar{3}\,1\,1/3)$\, including its full yukawa sector a
 nd a Higgs portal coupling $\\lambda_{S_{1H}}|H|^2|S_1|^2$. We implement t
 he model in FeynRules and use NLOCT to generate a UFO with UV counterterms
  and $R_2$ terms for MadGraph5_aMC@NLO\; it reproduces the Standard Model 
 cross section at $14$TeV to $0.06\\%$ and yields a UV-finite renormalized 
 $HHH$ vertex. Independently\, we compute the full one-loop amplitude (30 d
 iagramas with tirangle\, box and contact topologies) with FeynArts and Fey
 nCalc\, reduced to Passarino-Veltman functions\;it is UV finite and satisf
 ies the Ward identity for each class of diagrams. Both calculations agree 
 for the partonic cross section between 260GeV and 1TeV. For $M_{S_1}=1$TeV
  and $\\lambda_{S_1H}=1$\, the relative effect ranges from about $-15\\%$ 
 near threshold to $+2\\%$ at $1$TeV\, and amounts to $-1.0\\%$in the hadro
 nic cross section at $14$TeV. The corrected trilinear vertex alone account
 s for less than $10\\%$ of the effects\, which is driven by $S_1$ loops co
 upled to the gluons. We discuss the extension to the Manohar-Wise color oc
 tet and the $4321$ model at future collider energies.\n\nhttps://indico.nu
 cleares.unam.mx/event/2675/session/3/contribution/71
LOCATION:Puebla
URL:https://indico.nucleares.unam.mx/event/2675/session/3/contribution/71
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