Joint resummation for heavy quark production

We present the joint threshold and recoil resummed transverse momentum distributions for heavy quark hadroproduction, at next-to-leading logarithmic accuracy. We exhibit their dependence on the production channel and the color configurations, and compare t

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002 tcO 21 1v9410150/hp-pe:hviXraFebruary2,20084:14WSPC/INSTRUCTIONFILEjr

InternationalJournalofModernPhysicsA

cWorldScienti cPublishingCompanyJOINTRESUMMATIONFORHEAVYQUARKPRODUCTION

ANDREABANFI

CavendishLaboratory,UniversityofCambridge

MadingleyRoad,CB30HECambridge,UK

ERICLAENEN

NIKHEFTheoryGroup

Kruislaan409,1098SJAmsterdam,TheNetherlands

Wepresentthejointthresholdandrecoilresummedtransversemomentumdistributionsforheavyquarkhadroproduction,atnext-to-leadinglogarithmicaccuracy.Weexhibittheirdependenceontheproductionchannelandthecolorcon gurations,andcomparethesedistributionstoeachotherandtoNLO.Keywords:Resummation;heavyquarkproduction.

1.Jointthresholdandrecoilresummation

Theformalism1,2,3ofhadroniccrosssectionsforthejointresummationofdistri-butionssingularatpartonicthresholdandatzerorecoilhassofarbeenappliedtoZ/Wproduction4,Higgsproduction5,andpromptphotonhadroproduction6.Forthelatter2→2process,theformalismimplementsthenotionthat,inthepresenceofQCDradiation,theactualtransversemomentumproducedbythehard

collisionisnotp Tbutratherp T T/2,withQ Tthetotaltransversemomentumsoftrecoilingpartons. Q

ofunobservedThejoint-resummedpartonicpTspectrumtheformofahardscatteringcrosssectionasafunctionofp′T has

T/2|,con-volutedwithaperturbative,albeitresummedQ

Tdistribution.≡We| p

Thave Qextended7thejointresummationformalismtothepTdistributionofheavyquarksproducedinhadroniccollisions.Keydi erenceswiththeprompt-photoncaseare, rst,thepresenceoftheheavyquarkmassm,preventingasingularityinthehardscatteringfunctionwhenQT=2pTand,second,thepossibilityofmultiplecoloredstatesfortheproducedheavyquarkpair.

2.Resummedheavyquarktransversemomentumspectra

WeconsidertheinclusivepTdistributionofaheavyquarkproducedvia√thestronginteractioninahadron-hadroncollisionatcenterofmass(cm)energy