Doubly charmed B decay B D 0 K

Doubly charmed B decay B± D 0 K± ( for ~78 fb-1 ) JOLANTA BRODZICKA Institute of Nuclear Physics, Krakow April 09, 2003

Analysis details Ø at least 5 good tracks : abs(IP_dz)< 5 cm abs(IP_dr)< 0. 4 cm Ø R 2< 0. 3 Ø K± : P(K/ ) > 0. 4 ± : P( /K) > 0. 1 Ø D 0 reconstruction (see my December ICPV talk for details) • BF ~ 28% ( K , K 3 , K 0 , Ks. KK , KK ) • M (DREC) cut: ± 20 Me. V (D 0 K 0 : ± 50 Me. V) • vertex fit (conf_level>0. ) , mass constraint fit ØB± D 0 K ± reconstruction : B vertex fit: with IP and B lifetime constraints, cl_B > 0 (except B decays with D 0 K 0 ) no cos THR, cos PROD “shape” cuts Mbc > 5. 2 Ge. V JOLANTA BRODZICKA -0. 40 < E < 0. 35 Ge. V B DDK April 09, 2003

best B candidate choice method (see my December ICPV talk for more details) D probability : LR_D (MD) = S(MD)+B(MD) S(MD), B(MD) parameterization from MD fit B probability for B± D 0 D 0 BK± : LR_B = LR_D 1 • best B candidate : × LR_D 2 with max LR_B choice method efficiency for B± D 0 D 0 BK± (kpi) reconstr. eff is 15% efficiency lost due to B_best choice method is 0. 9% best = 82 % (for (kpi) ) (estimated from rejected MC events DE, Mbc distributions and correlations between accepted and rejected B candidates ) JOLANTA BRODZICKA B DDK April 09, 2003

D 0, D 0 B K N/7. 5 Me. V N/2 Me. V B± D 0 B K± Mbc E signal box: abs( E)<25 Me. V Mbc>5. 265 Ge. V S=28. 7± 6. 5 < > = 15. 0% eff BF = ( 1. 53 ± 0. 35 ) * 10 -3 = 2. 21*10 -4 JOLANTA BRODZICKA B DDK April 09, 2003

LR > 0. 04 N/2 Me. V N/7. 5 Me. V B± D 0 B K± Mbc E signal box: abs( E)<25 Me. V Mbc>5. 265 Ge. V ( for K 0 – 45< E<25 Me. V ) S=68. 6 ± 16. 4 eff = 4. 91*10 -4 JOLANTA BRODZICKA BF = ( 1. 64 ± 0. 39 ) * 10 -3 B DDK April 09, 2003

B± (3770) K± hypothesis (3770) D 0 B fitted function: BW+sqrt(1 -thr/x)*pol_3 BW position and width fixed to nominal (3770) values ~1. Me. V reconstructed M(D 0 D 0 B) for spike generated LR > 0. 04 N/14 Me. V D 0, D 0 B K N/0. 25 Me. V M(DD) resolution at (3770) region S = 2. 2 ± 2. 5 S = 15. 9 ± 6. 2 MASS D 0 D 0 B for signal_box events JOLANTA BRODZICKA B DDK April 09, 2003

reconstruction efficiency vs. Mass (D 0 D 0) 20 Me. V bins for 3 body MC B± D 0 B K± D 0, D 0 B K correct now! < > = 15. 0% (Previously wrong generated M(DD) distributions) MASS D 0 D 0 B D 0, D 0 B K 2 Me. V bins for 2 body MC B± (3770) K± < > = 16. 0% MASS D 0 D 0 B JOLANTA BRODZICKA B DDK April 09, 2003

B± D 0 B K± E distributions vs. M(D 0 D 0 B) JOLANTA BRODZICKA B DDK LR>0. 02 April 09, 2003

B± D 0 B K± E distributions vs. M(D 0 D 0 B) projections LR>0. 02 JOLANTA BRODZICKA B DDK April 09, 2003

E projections for different M(D 0 D 0 B) 80 Me. V regions LR>0. 02 JOLANTA BRODZICKA B DDK April 09, 2003

B± D 0 B K± fitted signal in each M(DD) 80 Me. V bin Signal80 Me. V LR>0. 02 2 lost signal box (partially reconstructed D*D*K ) lost signal box (partially reconstructed D*DK ) ( fully reconstructed DDK ) 1 st bin Psi(3770) region: 19 ± 6 M(D 0 D 0 B) JOLANTA BRODZICKA B DDK April 09, 2003