简介:Weintroducethepolarizedvalondistributionstodescribethespindependenceofpartondistributions.Thepolarizedvalondistributionsintheprotonandpolarizedpartondistributionsinsidethevaloncanhelptoobtainpolarizedpartondistributioninaproton.Inordertobeabletoobtainthespincontributionofseaquarks,weneedtoimprovethevalonmodelWeemploytheBernsteinpolynomialaveragestoobtaintheunknownparameterswhichexistinourcalculations.Ourresultsforthepolarizedprotonstructurefunction,xg1p,areingoodagreementwiththeexperimentaldataforsomevaluesofQ2.
简介:LargescaleQCDMonteCarlocalculationshavetypicallybeenperformedoneithercommercialsupercomputersorspeciallybuiltmassivelyparallelcomputerssuchasFermilab'sACPMAPS.Commodityclustersequippedwithhighperformancenetworkingequipmentpresentanattractivealternative,achievingsuperiorperformancetopriceratiosandofferingclearupgradepaths.WedescribetheconstructionandresultstodateofFermilab'sprototypeproductioncluster,whichconsistsof80dualPentiumⅢsystemsinterconnectedwithMyrinetnetworkinghardware.Wedescribesoftwaretoolsandtechniqueswehavedevelopedforoperatingsysteminstallationandadministration.WediscusssoftwareoptimizationsusingthePentium'sbuilt-inparallelcomputationfacilities(SSE),Finally,wepresentshortandlongtermplansfortheconstructionoflargerfacilities.
简介:Basedonthequark-gluoncontentsofnucleonandstronglybelievingthattheforcemediators,PomeronanditscounterpartintheconventionalapproachofReggetheory,forhighenergydiffractiveprocesswouldbethetensorglueballandOdderonrespectively,wediscussphoto-productionofvectormesonφoffthedeuteronatenergylessthan3GeVintheQCDinspiredmodelinwhichthequarkgluondegreesoffreedomandglueball,Odderonexchangearetakenintoaccount.Acalculationisperformedforγ+D→φ+D,andthetheoreticalpredictionsofthedifferentialcrosssectiondσ~(γD))/dt,arepresentedandcomparedwithavailableexperimentaldata.OurQCDinspiredmodelreproducesdataquitewellinthewholerangeoftheexperimentalmeasurementsupto|t|■0.4GeV.Ourresultscanbeusedtoextractγn→φndata,whichcannotbemeasuredinexperiment.
简介:Wereportourlatticesimulationonthecharmoniumspectrainthequenchedapproximation.Becausethecompleteadjustmentonallthenonperturbativeparametersneedsmuchcalculationtime,weonlyadjusttwoofthem,butwithsomerescalingformasssplitting.Aftertherescaling,thecalculatedmassesofmesonare3.030GeV(ηc),3.080GeV(J/ψ),3.546GeV(he)and3.412GeV(Xco)respectively,whichisinagreementwiththeexperimentalresults.
简介:影响量chromodynamic(pQCD)分析的perturbative的一个主要问题是为使QCD联合跑的重正常化可伸缩以便为物理observables的最大地精确的改正顺序预言被获得的一个方法的缺乏。最大的Conformality(PMC)的原则消除与常规重正常化规模背景过程联系的歧义,产出独立于重正常化计划的选择的预言。联合规模和夸克风味的有效数字的QCD在pQCD系列被给order-by-order。PMC有一个稳固的理论基础,令人满意自我一致性条件的标准重正常化组不变性条件和所有源于重正常化组。在每份订单的PMC规模被转移联合经常的s消除非保角的所有的强壮的力量的参数获得{在pQCD系列的i}条款。{没有歧义,i}条款从重正常化组方程被决定。跑在每份订单并且在每个阶段空间点联合的正确行为然后能被获得。在NC的PMC还原剂0Abelian限制到Gell-Mann-Low方法。在这份简短报告,我们总结我们PMC的最近的申请的结果到很多个collider过程,强调这条途径的概论和适用性。hadronicZ腐烂的讨论证明由使用PMC,没有规模歧义,一个人能在每份订单为全部、分开的腐烂宽度完成精确预言。我们也看那一个人是否采用PMC在next-to-next-to-leading顺序水平决定最高夸克的对提交向后不对称现象,一个人为不对称现象的Tevatron大小获得全面、前後一致的pQCD解释。这说明D0合作为增加t\(\overlinet\)观察的减少增加的行为不变的质量。在更低的精力,重夸克的尖分布能被用来获得重夸克潜力的一颗直接决心。巨大的夸克和雷普顿的尖分布的讨论也被介绍,包括到电磁的形式因素的二环的修正的fermionic部件。这些结果证明PMC的申请系统地为pQCD预言消除主要理论无常,因此增加的collider敏感到远非标准模型所及的可能的新物理�
简介:GiventhenullresultsofsearchesfornewphysicsattheLHC,weinvestigatetheone-loopeffectsSUSYQCDintheprocesse+e-→tgattheILCinMinimalSupersymmetricStandardModel(MSSM).WefindthattherelativeSUSY-QCDcorrectionstothecrosssectionofe+e-→tgcanmaximallyreach6.5%(3.2%)attheILCwith(1/2)s=1000GeVwhenm1=313.4GeVandmg=500(1500)GeV.
简介:Inthisarticle,wetaketheX(5568)asthediquark-antidiquarktypetetraquarkstatewiththespin-parityJ~P=0~+,constructthescalar-diquark-scalar-antidiquarktypecurrent,carryouttheoperatorproductexpansionuptothevacuumcondensatesofdimension-10,andstudythemassandpoleresidueindetailswiththeQCDsumrules.WeobtainthevalueM_X=(5.57±0.12)GeV,whichisconsistentwiththeexperimentaldata.ThepresentpredictionfavorsassigningtheX(5568)tobethescalartetraquarkstate.
简介:Inthisarticle,wecalculatethecontributionfromthenonfactorizablesofthadronicmatrixelementtothedecayB~0→χc1~π~0withthelight-conequantumchromo-dynamic(QCD)sumrules.Thenumericalresultsshowthatitscontributionisratherlargeandshouldnotbeneglected.Thetotalamplitudesleadtoabranchingfractionwhichisinagreementwiththeexperimentaldatamarginally.