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Analysis of B+→D0D*0K+ Decays and Signals for X(3872) Production in Particle Physics

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This study, conducted by J. Brodzicka and H. Palka at the Institute of Nuclear Physics, Krakow, focuses on the decay processes of B+ particles into D0D*0K+ and examines the X(3872) resonance. It details event selection criteria and analysis techniques, including mass and vertex fitting for D* and D mesons. The findings highlight signal plots and reconstruction methods that account for background and efficiency variations, presenting a comprehensive interpretation of the decay patterns and potential discoveries related to X(3872).

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Analysis of B+→D0D*0K+ Decays and Signals for X(3872) Production in Particle Physics

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  1. X(3872) D*0D0 ,D0D00 ( for ~140 fb-1 ) J.BRODZICKA, H.PALKA DCJune 21, 2004 INSTITUTEOF NUCLEAR PHYSICS, KRAKOW

  2. Analysis details DCJune 21, 2004 accepted events with:R2< 0.3 tracks with:abs(IP_dz)< 5cmabs(IP_dr)< 0.4cm K± :P(K/) > 0.4± : P(/K) > 0.1electron veto:el_id < 0.95 K0S :abs( M(+ -) - MKs ) < 15MeVonly good_K0s 0: E > 50 MeVabs( M( ) -M0 ) < 15MeV • D(*) reconstruction D0K, K3, K0, Ks, KK BF ~ 28%of total D±K, Ks, KK, KsK BF ~ 12%of total abs(M(D)-M(DPDG) ) < 20MeV ( D0 K0: -50MeV ) vertex fit (cl > 0.) and mass constraint fit applied, p(D) < 2GeVin (4S) system D*± D0±abs(M(D*±)-M(D)-mPDG) < 2.5MeV D*0 D00abs(M(D*0)-M(D)-mPDG) < 5MeV(contribution only from: vertex fit (cl > 0.)applied K, K0, Ks submodes ) • Breconstruction : all(22 + c.c)physical combinationsD(*)D(*)K B vertex fit:with IP and B constraints Mbc> 5.2 GeV -0.40 < E < 0.35 GeV J.BRODZICKA, H.PALKA

  3. ,D*0D0K+ B+ D0D*0K+ J.BRODZICKA, H.PALKA DCJune 21, 2004 INP, KRAKOW ( both D*0Kflavor comb.) LR > 0.01 Plot for Mbc>5.265GeV Exclusively reconstructed signal (from 2-dimlikelihood fit) N/7.5MeV XNSIG_1 77.9±13.7 XE0_1 0.0015± 0.0039 XEW_1 0.019± 0.003 XM0_1 5.2816± 0.0006 XMW_1 0.0034± 0.0005 E Plot for abs(E)<45MeV N/2MeV eff= (0.39 ± 0.03 ) *10-4 Mbc

  4. 3.872 abs( M(D0D*0)- 3.872 ) < 5 MeV 15 events (by counting) M(D*0D0) for B+ D0D*0K+ signal box events: Mbc > 5.265 GeV abs(E) < 45 MeV LR > 0.01 no LR cut N/1 MeV N/ 1 MeV 90% UL by counting method (Feldman-Cousins) BF(B+→K+X(3872))xBF(X(3872)→ D0D*0) <2.37x10-4 J.BRODZICKA, H.PALKA DCJune 21, 2004 INP, KRAKOW

  5. D(*) plots for ~11fb-1 sampleafter preselection S(MD) LR_D ( MD )= S(MD) B(MD) + + S(MD*) LR_D*( MD* )= S(MD*) B(MD*) J.BRODZICKA, H.PALKA DCJune 21, 2004 INP, KRAKOW Multi-candidates events treatment p(D) < 2GeVin (4S) system D, D* probabilities (LR): LR LR S(MD), B(MD) and S(MD*), B(MD*) parameterization from MD and MD*fits to data ( “inclusively” reconstr. D(*) ) MD MD B probability: LR_B = LR_D(*) × LR_D(*) LR LR best B candidate : with max LR_B MD* MD*

  6. ,D*0D0K+ B+ D0D*0K+ Effect of best B candidate choice (?) LR > 0.01 candidates rejected by the choice method for abs(E)<45MeV for Mbc>5.265GeV N/2MeV N/7.5MeV E Mbc no significant signalfor rejected candidates J.BRODZICKA, H.PALKA DCJune 21, 2004 INP, KRAKOW

  7. abs( M(D0D*0)- 3.872 ) < 5 MeV 10 events M(D*0D0) for rejected B+ D0D*0K+ events: Mbc > 5.265 GeV abs(E) < 45 MeV LR > 0.01 no LR cut N/1 MeV N/ 1 MeV 3.872 J.BRODZICKA, H.PALKA DCJune 21, 2004 INP, KRAKOW

  8. 3.872 abs(M(D0D*0)- 3.872) < 5 MeV 25 events M(D*0D0) for best + rejected B+ D0D*0K+ candidates Mbc > 5.265 GeV abs(E) < 45 MeV no LR cut N/1 MeV including background and multiple B candidates J.BRODZICKA, H.PALKA DCJune 21, 2004 INP, KRAKOW

  9. E distribution : abs(M(D0D*0) - 3.872) < 5 MeVMbc > 5.265 GeV no LR cut best B + rejected candidates best B only N/10 MeV E E Peak @ - 40 MeV Effect of cross-feed from other B D(*)D(*)K modes? (it is significant background for B+ D0D*0K+ ) J.BRODZICKA, H.PALKA DCJune 21, 2004 INP, KRAKOW

  10. x-talk between D0D*0K+ and D*0D0K+(for 20K generated (K) x (K) events) Mbc > 5.265 GeV abs(E) < 45 MeV M(D*0D0) for cross-feed events to B+ D0D*0K+ mode x-talk from B+ D*-D0K+(for 20K generated (K) x (K) events) N/10 MeV 3.872 N/10 MeV The cross-feed events do not group at 3.872 J.BRODZICKA, H.PALKA DCJune 21, 2004 INP, KRAKOW

  11. B+ D0D0K+ LR > 0.04 Plot for Mbc>5.265 GeV N/7.5MeV E Region @ -150MeV : B+ D0D*0K+ (orB0  D*-D0K+ ) partially reconstructed (with missing ): We can search for: X(3872)  D0 D00( in X(3872)  D*0 D0 0 fromD*0almost at rest) looking atM(D0 D0)@ 3.872 - 0.135 = 3.737 GeV J.BRODZICKA, H.PALKA DCJune 21, 2004 INP, KRAKOW

  12. M(D0D0)for B+ D0D0K+missing  signal box events: no LR cut Mbc > 5.265 GeV abs(E+0.150) < 50 MeV N/1 MeV 3.737  20 events above background LR > 0.04 LR > 0.01 N/1 MeV 3.737 J.BRODZICKA, H.PALKA DCJune 21, 2004 INP, KRAKOW

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