B Pietrzyk040303

Status of Bose-Einstein analysis: 

Status of Bose-Einstein analysis Bolek Pietrzyk LAPP Annecy-le-Vieux

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changes in analysis Final ALEPH data Track selection adapted to final data Thanks to Isabelle De Bonis Evevt selection from the W mass group (v60) Thanks to Stephane Jezequel New global MC tuning BE32 Thanks to Gerald Rudolph and Brigitte Bloch BE analysis is very similar to the Frank’s Martin analysis

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Mixed method in ALEPH We compare fully hadronic W-pair decay with events “constructed” from hadronic parts of two semileptonic events. Thus “constructed” (mixed) events have Bose-Einstein correlations in each W decay and no BE correlations between pions from different W’s. The Wqqbar(W1) of the first WWq1q2bar event is boosted to its center of mass frame. Then, it is boosted in such a way that the final W1 momentum is –PW2, where PW2 is the Momentum of the Wqqbar of the second WWq1q2ln event. W2 has opposite sign to W1.

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today Comparison of new and old results (100 MeV) Go to 40 MeV binning Do some fits (D) and integrations (Dr) Systematics Some numbers Plans for the future

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D’ with background Osaka 00 now

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D’ with and without background (now) with without

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Dr with background Budapest 01 now

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Dr with and without background (now) with without

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Dr without background Budapest 01 now

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D’ with different binning 100 MeV 40 MeV

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D’ fit with fixed width (2 param.) D’(Q)=k(1+le-s2Q2) Data l=0.020+-0.012 k=0.991+-0.002 BEI BEB l=0.014+-0.005 k=0.999+-0.001 l=0.091+-0.005 k=0.993+-0.001 Data-BEI/BEB-BEI=8% (stat. uncert. only)

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D’ fit (3 param.) D’(Q)=k(1+le-s2Q2) Data l=0.105+-0.049 s=6.99+-1.76 k=0.991+-0.002 BEI BEB l=0.030+-0.014 s=5.13+-1.41 k=0.999+-0.001 l=0.091+-0.007 s=2.61+-0.14 k=0.993+-0.001 I=0.0133 +-0.0046 I=0.0052 +-0.0017 I=0.0309 +-0.0017 Data-BEI/BEB-BEI=32% (stat. uncert. only)

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Dr with different binning 100 MeV 40 MeV

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Dr integration Data BEI BEB 6ch=0.075+-0.060 15ch=-0.101+-0.148 Integral 6ch=0.028+-0.021 15ch=0.022+-0.054 6ch=0.297+-0.022 15ch=0.743+-0.054 Data-BEI/BEB-BEI(6)=17% Data-BEI/BEB-BEI(15)=-17%

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D’ like and unlike sign pairs like unlike

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Dr like and unlike sign pairs like unlike

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Track selection systematics on data no –BEI yet

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Event selection systematics on data no –BEI yet Compare qqqq selection with NN cut 0.3 (W mass) and 0.05 (xsection)

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Background subtraction Osaka 00 ALEPH global tuning l = 1.11 DELPHI global tuning l = 1.35 back. subtr. l = 0.9 ALEPH back.subtr. syst. l = 0.9

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Background subtraction systematics on data no –BEI yet

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Total systematics on data no –BEI yet

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Not complete systematics on data (as today) D’ L D’integr Dr integr = 0.0065+-0.0128+-0.0120 (8% BEB-BEI) BEB-BEI = 0.0772 =-0.079+-0.148+-0.444 (-11%BEB-BEI) BEB-BEI = 0.721 =0.0081+-0.0046+-0.0040 (31% BEB-BEI) BEB-BEI = 0.0257 Bin-to-bin correlations are not included in stat. uncertainties BEI MC not included in sys. uncertainties

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What to do? To do : Bin-to-bin correlations Finish systematics Correct by BEI instead of standard MC??? Planning : April 10th : draft 1 of the paper April 20th : inform other collaborations May 10th : draft 2 June 10th : submit paper to Editorial Board June 30th : Editorial Board  Submit to summer conferences