Download presentation
Presentation is loading. Please wait.
Published byJerome Doyle Modified over 9 years ago
1
Spectroscopy and New Resonances at Belle B. Golob University of Ljubljana, Slovenia Belle Collaboration B. Golob, Belle Lake Louise Winter Inst., 2006 Experimental environment X(3872) quant. numbers → Z(3930) - c2 ’ Y(3940) X(3940) Summary
2
Experimental environment B. Golob, Belle Lake Louise Winter Inst., 2006 ~1 km in diameter Mt. Tsukuba KEKB Belle 8 GeV e - 3.5 GeV e + KEKB asymmetric B factory Υ(4s) e+e+ e-e- B B > 1 fb -1 /day (>1 M BB/day) ∫Ldt ~ 500 fb -1 on reson. 50 fb -1 off reson. ~550 M BB available data Integrated luminosity May ‘99 Feb ‘06 e+e+ e-e- ** u,d,s,c Belle
3
X(3872) Observed by Belle B ± → K ± + - J/ 152M BB,PRL91,262001(2003) B. Golob, Belle Lake Louise Winter Inst., 2006 275M BB,hep-ex/0505038 Br(B→XK) Br(X→ + - J/ = (1.31±0.24±0.13)x10 -5 B ± → K ± J/ 275M BB,hep-ex/0505037 B ± → K ± c J calibration mode, 0 veto no. of B’s in bins of M( J ) 13.6±4.4 evts.(4 ) C(X(3872))=+1 M=3872 MeV/c 2 =13 MeV/c 2 charmonium, DD*, tetraquarks...? world average: M=3871.9±0.5 MeV/c 2 M( + - l + l - )-M(l + l - ) X(3872) E.S.Swanson,PLB588,189(2004) L.Maiani et al.,PRD71,014028(2005) ’’
4
X(3872) B. Golob, Belle Lake Louise Winter Inst., 2006 ++ -- l+l+ l-l- X(J/ ) angular distributions in B ± → K ± X( + - J/ ) examples: |cos | side band 2 /nof=31/9 275M BB,hep-ex/0505038 X→ J/ S-wave expected -- ++ K B X(J/ ) J PC =0 ++ J PC =1 ++ |cos | 2 /nof=5/9 X → J/ ang. distrib. M( + - ) in X→ + - J/ disfavor all of J=0,1,2 cc states except 1 ++, 2 ++ X→ D 0 D 0 0 ?? 1 ++ →DD* S-wave 2 ++ →DD* D-wave, suppressed by (q*) 2L+1
5
preliminary X(3872) B. Golob, Belle Lake Louise Winter Inst., 2006 N=12.5±3.9 (>5 ) Br(B K X) Br(X DD ) =(1.6±0.4±0.3) 10 -4 B→KD 0 D 0 0 /KD 0 D* 0 M(D 0 D 0 0 ) in B signal region M(D 0 D 0 0 ) ≈ M(X) Br(X DD )/Br(X→ + - J/ =12±5 hard to accomodate with a 2 ++ state J PC (X(3872))=1 ++
6
Z(3930) B. Golob, Belle Lake Louise Winter Inst., 2006 395fb -1,hep-ex/0512035 acc. to PRL e+e+ e-e- D D un-tagged D 0 →K , K 0, K3 D + →K p t (DD)<0.05 GeV/c 64±18 evts M=3929±5±2 MeV/c 2 =29±10±2 MeV M(DD)[GeV/c 2 ] D side band acceptance corrected D side band J=2 expect. 2 /nof=1.9/9 J=0 expect. 2 /nof=23.4/9 Z ≡ c2 ’ 2 3 P 2 cc 5.3 *: D, beam axis in frame S.Godfrey,N.Isgur,PRD32,189 (1985) C.R.Münz,Nucl.Phys.A609,364 (1996)
7
B. Golob, Belle Lake Louise Winter Inst., 2006 275M BB, PRL94, 182002(2005) M 2 (J/ ) M 2 (K ) Dalitz plot for B → K J/ B ± → K * J/ K * → K ± resonant structure? M(Y)=3943±11±13 MeV =87±22±26 MeV 58 ± 11 evts. >8 Y(3940) No. of B’s in bins of M( J/ ) M(J/ ) Br(B → YK) Br(Y → J/ )= (7.1±1.3±3.1) x10 -5 radially excited P-wave cc? large Br(Y→ J / ) cc-gluon hybrid? suppressed D ( * ) D ( * ) decays predicted M≥4.3 GeV F.E.Close,P.R.Page, Nucl.Phys.B443,233(1995) C.Banner et al., PRD56,7039(1997)
8
J/ X e-e- e+e+ Reconstruct J/ → l + l - recoil mass (mass of X): X(3940) B. Golob, Belle Lake Louise Winter Inst., 2006 357fb -1,hep-ex/0507019 subm. to PRL 266±63 evts M~3936 MeV/c 2 (M rec )~ 30 MeV/c 2 55 X(3940)→D ( * ) D ? reconstruct J/ + one D constrain M rec ( J/ D)=M(D ( * ) ) (M rec ( J/ ))~10 MeV/c 2 M rec ( J/ D)=M(D) M rec ( J/ D)=M(D*) M=3943±6±6 MeV/c 2 <52 MeV @90% C.L. 24.5±6.9 evts 5
9
X(3940) B. Golob, Belle Lake Louise Winter Inst., 2006 357fb -1,hep-ex/0507019 subm. to PRL no evidence for X(3940)→J/ X(3940)≠Y(3940) inclusive/D*D tagged sample, common evts removed B >2 (X→D*D) > 45% @90% C.L. B(X→D D) < 41% @90% C.L. B(X→J/ ) < 26% @90% C.L. several speculations on X(3940) nature, all pro’s and con’s; further experimental study (ang. distrib.)
10
Summary KEKB is also a great source of charm & cc states Some expected, ma ny unexpected/puzzling observations/discoveries understanding range of questions: what are they? anomalous properties? all properties as expected? D sJ X(3872) Y(3940) X(3940) c (2800) broad D ** PQ B. Golob, Belle Lake Louise Winter Inst., 2006 c2 ’ existence?
11
new stateproductiondecay modeto establish next reference X(3872)B → KX + - J/ + - 0 ( ) J/ J/ quantum num., decay modes hep-ex/0408116 hep-ex/0505038 hep-ex/0505037 c2 ’ DDquantum num. hep-ex/0512035 Y(3940)B → KY J/ decay modes PRL94,182002(2005) X(3940)continuum, cc recoil M recoil,DD * quantum num. hep-ex/0507019 broad D ** B → D ** + D (*) Br’s PRD69,112002 hep-ex/0412072 c (2800) continuum c+c+ , (mixing) PRL94,122002(2005) D sJ continuum B → DD sJ, B → D sJ K D s 0, D s * 0, D s Br’s BELLE-CONF-0461 hep-ex/0507064 c (2s) continuum, cc recoil M recoil PRD(R)70,071102 + (1540) sec. int. pKpK S existence? PLB632,173(2005) +, *++, c 0, c *+ B decayspK S,pK +, D ( * )- p,D 0 p existence? hep-ex/0411005
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.