Reparametrization Invariance, the controversial extraction of $alpha$ from $Btopipi$ and Ne

《Reparametrization Invariance, the controversial extraction of $alpha$ from $Btopipi$ and Ne》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、IFIC/07-17FTUV-07-0402ReparametrizationInvariance,thecontroversialextractionofαfromB→ππandNewPhysicsFranciscoJ.Botellaa,MiguelNebotbaDepartamentdeF´ısicaTe`oricaandIFIC,UniversitatdeVal`encia-CSIC,E-46100,Burjassot,SpainbCentrodeF´ısicaTe´oricadePart´ıculas(CFTP),InstitutoSuperiorT´ecnico,P-1049-0

2、01,Lisboa,PortugalAbstractTheextractionoftheweakphaseαfromB→ππdecayshasbeencontroversialfromastatisticalpointofview,asthefrequentistvs.bayesianconfrontationshows.Weanalyseseveralrelevantquestionswhichhavenotdeservedfullattentionandpervadetheextractionofα.ReparametrizationInvarianceprovesappropriat

3、etounderstandthoseissues.WeshowthatsomeStandardModelinspiredparametriza-tionscanbesenselessorinadequateiftheygobeyondtheminimalGronauandLondonassumptions:thesingleweakphaseαjustinthe∆I=3/2amplitudes,theisospinrelationsandexperimentaldata.Besidethoseanalyses,weextractαthroughtheuseofseveralade-quat

4、eparametrizations,showingthatthereisnorelevantdiscrepancybetweenfrequentistandbayesianresults.Themostrelevantinforma-tion,intermsofα,istheexclusionofvaluesaroundα∼π/4;thisresultisvalidinthepresenceofarbitraryNewPhysicscontributionsarXiv:0704.0174v1[hep-ph]2Apr2007tothe∆I=1/2piece.11IntroductionThe

5、extractionoftheCPviolatingphaseα[1]hasleadtosomerecentcon-troversyconfrontingtheresultsandstatisticalmethodsoftwodifferentcol-laborations:thefrequentistapproachadvocatedinreferences[2,4]andthebayesianapproachemployedinreference[3].Inreference[2]J.Charlesetal.presentedanimportantcriticismtothebayesi

6、anmethodsusedbytheUTfitcollaborationinordertoextracttheangleαoftheunitaritytriangleb–dfromππandρρdata.Thecriticismreliesheavilyonthestatisticaltreatmentofdata:frequentistvs.bayesian.TheansweroftheUTfitcollaboration[3]risessomeinterestingpoints,bothontheinterpretationoftheresultsandontheimportanceoft

7、hephysicalassumptionsonthehadronicamplitudes.Theauthorsof[2]haverecentlyansweredtothisUTfitreplyin[4].Theaimofthepresentworkistoclarifyseveralissuescentraltoanadequateunderstandingofthephysicsatstake.Wealsowanttoc