We present the fully differential production and decay of a W' boson, with arbitrary vector and axial-vector couplings, to any final state at next-to-leading order in QCD. We demonstrate a complete factorization of couplings at next-to-leading order in bot
Fullydi erentialW′productionanddecayatnext-to-leadingorderinQCD
ZackSullivan
TheoreticalPhysicsDepartment,FermiNationalAcceleratorLaboratory,Batavia,IL,60510-0500
(July23,2002)Wepresentthefullydi erentialproductionanddecayofaW′boson,witharbitraryvectorandaxial-vectorcouplings,toany nalstateatnext-to-leadingorderinQCD.Wedemonstrateacompletefactorizationofcouplingsatnext-to-leadingorderinboththepartialwidthoftheW′boson,andinthefulltwo-to-twocrosssection.WeprovidenumericalpredictionsforthecontributionofaW′bosontosingle-top-quarkproduction,andseparateresultsbasedonwhetherthemassoftheright-handedneutrinoνRislightenoughfortheleptonicdecaychanneltobeopen.Thesingle-top-quarkanalysiswillallowforanimproveddirectW′masslimitof525–550GeVusingdatafromrunIoftheFermilabTevatron.Weproposeamodi edtolerancemethodforestimatingpartondistributionfunctionuncertaintiesincrosssections.
arXiv:hep-p
h
/0207290v1 23 Jul 2002
I.INTRODUCTION
Sincetheintroductionofthestandardmodel,manyextensionshavebeenproposedthatinvolveenhancedgaugesymmetries.Onecommonfeatureofthesemodelsisthepredictionofadditionalgaugebosons,genericallycalledW′andZ′bosons.Innon-universalandtop- avormodels,theW′gaugebosonarisesfromanewSU(2)Lsectorthatdistinguishesbetweengenerationsoffermionsandmaytreatquarksandleptonsdi erentlyTheW′bosoncouldbethelowestKaluza-KleinmodeoftheWboson[7],oraheavymasseigenstateinnon-commutingextendedtechnicolor[8].Inaleft-rightsymmetricmodeltheW′andstandard-modelWbosonsareremnantsofabrokenSU(2)L×SU(2)RsymmetryTheresultingleft-rightmixingmaybenaturallysuppressedbyorbifoldbreakingoftheleft-rightsymmetryorbysupersymmetricinteractionsWhileindirectboundsmaybeplacedonthemassesandcouplingsofthesevariousW′bosonswithinthecontextoftheirexplicittheories,itisalwaysadvantageoustosearchforthesenewparticlesdirectly.Inordertofacilitateadirectexperimentalsearch,andtoachievethemostgeneralcontactwiththeory,wecalculatethefullydi erentialnext-to-leadingordercrosssectionfortheproductionanddecayofaW′bosontoany nalstatewitharbitraryvectorandaxial-vectorcouplings.
ThemostgeneralLorentzinvariantLagrangiandescribingthecouplingofaW′tofermionsmaybewrittenas
L=
g2
whereζisaleft-rightmixingangle,andωisaCP-violatingphasethatcanbeabsorbedintoVR.Inthisnotation,
aregeneralizedCabibbo-Kobayashi-Maskawa(GCKM)matrices.gR(L)aretheright(left)gaugecouplings,andVfR,Lifj
InmodelswheretheWandW′mix,themixingangleζisusuallyconstrainedtobesmall(|ζ|<afew×10 5–10 2[16]).Hence,thesearchforpurelyright-orleft-handedstatesappearswellmotivated.
ManydirectsearchesforW′bosonshavebeenperformedathadroncolliders.Mostexperimentalanalyseshaveconsideredleft-orright-handedW′bosons,withstandard-model-likecouplings,thatdecayintoleptonic nalstates.
′′
Left-handedWLbosons,orright-handedWRbosonsinwhichthedecayintoaright-handedneutrinoνRiskinemati-callyallowed,areconstrainedtohavemassesmW′>786GeVIfmνR>~mW′thedecaytoνRisnotallowed,′
andtheright-handedWRbosonsareonlydirectlyconstrainedbypeaksearchesinthedijetdata.UnlesstheW′hasgreatlyenhancedcouplingstolightquarks,thedijetdataarelimitedbyQCDbackgroundstoprovidingamasslimitof420GeVTheonly nalstatenotmeasuredbyoneoftheexperimentslistedaboveinvolvesthedecayofaW′toasingletopquark.InRefs.itwaspointedoutthatadeviationofmeasuredthesingle-top-quarkcrosssectionfromthe
′ L
√fiγµgReiωcosζVfRWfj+H.c.,PP+gsinζVLRLfffijij
(2)
Fully differential W' pr... 暂无评价 23页 ... production at next-to-leading order SUSY-QCD...Decay and production processes through these ...
Next-to-leading order co... 暂无评价 31页 免费 The fully differential ...(NLO) QCD corrections to the production and the decay of the top quark....
The fully differential s... 暂无评价 37页 ... Next-to-leading order QCD corrections to top ...Note that both the production and decay density ...
Fully differential W' pr... 暂无评价 23页 ...Decay Distributions to Next-to-Leading Order隐藏>...(non QCD partons), (1) where Xq is any ...
Next-to-leading order QCD corrections to light ... higgs doublet model in the form of a fully ?...production followed by the decay, H 0 → h0 ...
Fully differential W' pr... 暂无评价 23页 ...decay in next-to-leading order in LEET and CP...QCD sum rules or light-cone sum rules (LCSR)[...
The calculation is fully differential in the final state particle momen...更多>>The next-to-leading order QCD corrections to the production of a $W$-...
Hard Scattering in QCD w... 暂无评价 37页 ...fully differential decay distribution of polarized ...production and decay at next-toleading order in ...
On the NLO QCD corrections to Higgs production and decay in the MSSM We...ects [6], an estimate of the next-to-next-to-next-to-leading order (...
The ?nal aim of our work is a complete next to leading order QCD computation of top production and decay at an e+ e? collider. I wish to thank ...
我要评论