Slide 1

New Resonances at Belle B. Golob University of Ljubljana, Slovenia Belle Collaboration B. Golob, Belle Cracow Epiphany Conference, 2005 Experimental environment D sJ s and their properties X(3872)......and also Y(3940) cc recoil spectrum pentaquarks? Conclusion Slide 2 B. Golob, Belle Cracow Epiphany Conference, 2005 Experimental environment KEKB asymmetric B factory ~1 km in diameter Mt. Tsukuba KEKB Belle (4s) e+e+ e-e- B B Ldt = 255 fb -1 on reson. 30 fb -1 off reson. ~280 M BB > 900 pb -1 /day (~1 M BB/day) Integrated luminosity May 99 Oct 04 Slide 3 B. Golob, Belle Cracow Epiphany Conference, 2005 Experimental environment combined particle ID (K )~85% ( K ) B. Golob, Belle Cracow Epiphany Conference, 2005 D sJ states Production in continuum backup slide reconstruction: D s K + K - D s * D s p(D sJ )>3.5 GeV D sJ + (2317) D s + 0 D s side band 0 side band D s *+ (2112) also D s + (2460) D s *+ 0 ; lost (MC) D sJ + (2460) D s *+ 0 D s * side band D s + (2317) D s + 0 +random D sJ + (2460) D s + D s side band M(D sJ (2317))=2317.2 0.5 0.9 MeV M(D sJ (2460))=2456.5 1.3 1.3 MeV (D sJ (2317)) B. Golob, Belle Cracow Epiphany Conference, 2005 Y(3940) B K J/ backup slide Main syst. uncertainty: fit using S-wave BW or Lorentzian shape for resonance; linear or 3rd order polynomial for bckg.; largest deviation +38% possible non- 3 contribution; -28% Significance: integral of fitted phase space in first 3 bins of M( J/ ) 16.81.4 total number of events: 55.6 significance > 9 > 8 Slide 49 cc recoil backup Slide 50 B. Golob, Belle Cracow Epiphany Conference, 2005 J/ X e-e- e+e+ Reconstruct J/ l + l - Calculate recoil mass (mass of X): backup slide calibrate with e + e - (2S) (2S) J/ + - B. Golob, Belle Cracow Epiphany Conference, 2005 Isotriplet of charmed baryons c + - final state: 4 excited charmed baryons lower two orbital excitations of c + upper two ? c + final state: c (2455) ground state c (2520) spin excitation c orbital excitations? c-c- c0c0 c+c+ side band Fit: D-wave BW + feed-down + comb. backg. backup slide feed-down c + (2880) c + + - through c (2455) 0, c (2455) ++ feed-down not seen due to lower ( 0 ) Full recon. of c + (2880) c + + - for signal events in bins of M( c )-M( c ) to determine the amount of feed-down 2.24x10 3 1.54x10 3 2.81x10 3 x p >0.7 Slide 56 B. Golob, Belle Cracow Epiphany Conference, 2005 Isotriplet of charmed baryons backup slide M( c )-M( c ) full region: c (2455) 0 c (2520) 0 estimation of syst. uncertainty: - change of signal descr. (L=0,1) - change of comb. bckg. descr. - change of down-feed contrib. - change of x p and other selection criteria c pK - + c pK S c + c (2800)/ c yield ratio cross-check: Slide 57 c p structure backup Slide 58 B. Golob, Belle Cracow Epiphany Conference, 2005 c + p structure 3-body baryon production in B decays: baryon-antibaryon system peaked near treshold B - c + p - c + pK - +,pK S, +, pK S + -, + + - p - 26420 evts. c (2455) 0 c (2520) 0 (1600) (2420) Fits to E in mass bins BW peak + feed down from B - c + M = 3.35 0.02 GeV 50 10 evts.(5.6 ) ~70 MeV 152M BB,hep-ex/0409005 Slide 59 B. Golob, Belle Cracow Epiphany Conference, 2005 c + p structure c (2455) 0 p c + (1232) c + (1600) c + (2420) c + p simultaneous fit to 6 E distrib.; N i = j ij Y j Br(B - c (2455) 0 p)=(3.67 +0.74 -0.66 0.36 0.95)10 -5 Br(B - ( c + p) - )=(3.87 +0.77 -0.72 0.43 1.01)10 -5 due to Br( c + pK - + ) M=3.35 +0.01 -0.02 0.02 GeV =0.07 +0.04 -0.03 0.04 GeV from different bkgd. param.