Stop-Stop-Higgs Production at future Linear Collider

In the Minimal Supersymmetric Standard Model, the cross section for the associated production of the lightest neutral Higgs boson with the lightest top squark pairs can be rather substantial at high energies. We summarize the properties of this production

PM/99–37

STOP–STOP–HIGGSPRODUCTION9

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A.DJOUADI,J.-L.KNEURaandG.MOULTAKAPhysiqueMath´ematiqueetTh´eorique,UMRNo5825–CNRS,Universit´eMontpellierII,F–34095MontpellierCedex5,France

IntheMinimalSupersymmetricStandardModel,thecrosssectionfortheassoci-atedproductionofthelightestneutralHiggsbosonwiththelightesttopsquarkpairscanberathersubstantialathighenergies.Wesummarizethepropertiesofthisproductionprocessatafuturee+e linearcollider,includingtheγγmode.

1Introduction

IntheMinimalSupersymmetricStandardModel(MSSM)1,ifthemixingbetweenthirdgenerationsquarksislarge,stops/sbottomscanberatherlight2andatthesametime,theircouplingtoHiggsbosonscanbecomesubstantial.ThismighthavearatherlargeimpactonthephenomenologyoftheMSSMHiggsbosons3 7.Moreprecisely,concentratingonscalartopquarks,theirmasseigenvaluesaregivenby

m2 212 222t1,2=mt+(m2QL

m t

R

+···)+4mtAt ,(1)wheremQ L,m t

Rarethesoft-SUSYbreakingscalarmassesandthedotsstandfortheD–terms∝MandtheZ2

cos2β.Inthedecouplinglimit(thelightesthbosonisStandardModellikeotherbosonsA,HandH±,areveryheavy),theexpressionsthecouplinght 1t

of

1simplyreads(θtisthemixingangleandsW≡sinθW) 1 t1 13sWcos2θt +m2gmtA tht=cos2β2

t2

sin2θt

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