PHOTOS MC: simulate OED effectsNormalwaytostudyQEDradiativecorrectionUsing Feynman rules, calculate [MBorn/2Calculate virtual QED corrections α [MBorn/2 × virtCalculate soft and collinear photon contribution IMBorn/2 × Osoft/clinearS = Ovirt + Osoft 4freeofIRandcollineardivergencescollinearCalculatenon-collinearphotoncontribution,add corrections ofvirtualandreal photon together,we get one-looplevel result[MBorm2 (1+ ) dLipSn + [M|non-colinear dLipSn+1MCEventGenerator，徐庆君6
MC Event Generator, 徐庆君 6 PHOTOS MC: simulate QED effects Using Feynman rules, calculate Calculate virtual QED corrections Calculate soft and collinear photon contribution = + + free of IR and collinear divergences Calculate non-collinear photon contribution, add corrections of virtual and real photon together, we get one-loop level result Normal way to study QED radiative correction (1 + ) + non-collinear
PHOTOS MC: simulate QED effectsPHOTOS MC simulates hard photonemission from finalstatesAprocess independentkernelis used instead of exact matrix elementit satisfies: in soft and collinear limits, Lim Mkernel/2 = [MBom/? × osoft/colinear[Mexact/? = [Mkcrncl|2 + remaining partAffectsthePhasespaceisexact,factorizedintoprecisionkydkydcosédodLipSn+1(P)XdLipsn(p-ki...kn)2(2元）Events(supposetobeeventswithBorn levelAmplitudeand phasespaceand withouthard photon)AffectstheprecisionProcess independentkerneland exact phasespaceEventswithhardphotonMCEventGenerator,徐庆君
MC Event Generator, 徐庆君 7 PHOTOS MC: simulate QED effects PHOTOS MC simulates hard photon emission from final states A process independent kernel is used instead of exact matrix element, it satisfies: in soft and collinear limits, Lim = = + remaining part Phase space is exact, factorized into Born level Amplitude and phase space Process independent kernel and exact phase space Events (suppose to be events with and without hard photon) Events with hard photon