1 Stefan Spanier, PHP 2008 Workshop, JLAB Some Issues in Meson Spectroscopy Crystal Barrel and B-Factory Experiences Stefan Spanier University of Tennessee, Knoxville 2 Stefan Spanier, PHP 2008 Workshop, JLAB Introduction Scalars in D and B Decays Initial State Radiation Study of Charmonia The D SJ States 3 Stefan Spanier, PHP 2008 Workshop, JLAB qq Mesons L = exotic nonets 0 1 + 1 2 + 2 Glueballs Hybrids GeV 4.4 GeV in cc GeV Lattice QCD L s1s1 s2s2 S=1, L=0 + gluon _ Spectroscopy 4 Stefan Spanier, PHP 2008 Workshop, JLAB Access to gluon rich states in pp Annihilation For Hybrids, the angular momentum in the flux tube transfers to one of the daughter mesons (L=1) and (L=0) meson. L=0: , , , , L=1: a,b,h,f, not preferred. 1 b 1, f 1, , a 1 E852: a 2 (1320) dominates + P-wave resonance VES : resonances; also just phenomenolog. Bkg t-channel exchange ( -pole) [PRL 91(2003)092002] E852: m~1260MeV lower (m=1370MeV in diff.) VES : a 2 (1320) dominates; no 1 0 CBAR: I ( 1 (1400)) ~ I (a 2 (1320)); S=1 initial state CBAR: 2% content; 1 S 0 initial only; or S=1, FSI CBAR+OBELIX: resonance from S=0 initial state Exotic waves? Resonances? 1 (1400) 5 Stefan Spanier, PHP 2008 Workshop, JLAB Kaon Identification with the BaBar DIRC 6 Stefan Spanier, PHP 2008 Workshop, JLAB Scalars are special As states are mixtures: a nn + b ss + c qqqq + d glue + Decay obscures quark content need to study production and decay ____ too many / heavily shifted ! Experiment: - broad states - often covered by tensors - featureless decay angle distributions 1+2+ Compare to non-perturbative QCD (meson spectrum) quantum numbers 3 P 0 (vacuum) 7 Stefan Spanier, PHP 2008 Workshop, JLAB Formalism for X 3 body (Dalitz plot analysis) a b c d ll R L l Spectator ? d R c assuming dominance by 2-body interaction (isobar model) scalar resonances strongly overlap / decay channels open in vicinity Dynamic amplitude not just a simple Breit Wigner - Analytic - Unitary (2-body subsystem) - Lorentz-invariant K-matrix formalism widely used: 2-body scattering production / decay R = (1-iK ) -1 2-body PS T = R K F = R P P-vector = Q T Q-vector Watson theorem: same phase motion in T and F in elastic range Adler zero: at m 0 for p =0: T = 0 near threshold; also/where for F ? Resonance: = pole in unphysical sheet of complex energy plane 8 Stefan Spanier, PHP 2008 Workshop, JLAB Scalars in D, D S, and B Decays Initial state is single, isolated particle with well defined J B,D =0, J D s =1 Decay-operators have simple lorentz and flavor structure Short range QCD properties are known (better) Weak decay defines initial quark structure; and rules (e.g. I=1/2) Large variety of transitions to different flavor and spin states with large mass differences of the constituent quarks - combined/coupled channel analyses - isospin relations (simple BF measurements) - semileptonic decays (true spectator, form factors) Access to higher mass scalar states in B (?) Input for B CP physics - add penguin modes for New Physics Search, e.g. B 0 f 0 K 0 - CP composition of 3-body modes, e.g. B 0 K 0 K + K - - hadronic phase for CP angle in B DK from D-Dalitz plot 9 Stefan Spanier, PHP 2008 Workshop, JLAB Experiments c.c. E791 - (500 GeV) [Pt, C] charm Focus Brems [Be] charm BaBar 2008 Belle > 2008 CLEO-c e + e - (3S) DD 281pb -1 e + e - Y(4S) _ B-factories are also D-factories: In each expect >> 2 Million of E ,400 1 FOCUS - 120,000 2 CLEO-c - D 0 K - + : 51,200 3 BaBar 1. E791 Collaboration, Phys.Rev.Lett. 83 (1999) Focus Collaboration, Phys.Lett. B485 (2000) CLEO-c: hep-ex/ fb -1 > 500 Million BB pairs took more than 10BB / sec _ _ D 0 K - + _ + 10 Stefan Spanier, PHP 2008 Workshop, JLAB I=1 Scalar a 0 (980) in D decays (1020) f 0 (980) (770) K*(892) a 0 (980) f 0 (980) Efficiency: Data: BaBar D0K0S+ -D0K0S+ - D0K0SK+K-D0K0SK+K- a 0 (980) BaBar #92935 #13536 ~100fb % purity 11 Stefan Spanier, PHP 2008 Workshop, JLAB I=1 Scalar a 0 (980) / a 0 (1450) 0 fixed by total BF couplings g i (also tune lineshape) e.g. F 1 : X F 2 : X KK) Production amplitude 2 Flatte formula: Scattering amplitude 5 parameters 12 Stefan Spanier, PHP 2008 Workshop, JLAB I=1 Scalar a 0 (980) in D decays weight/ 5 MeV/c 2 Extract S-wave and describe Flatte formula with Crystal Barrel parameters [Abele et al., PRD 57, 3860 (1998)] Moment analysis only S and P waves Fix m 0 and coupling g , but float g KK Best description of S-wave from moments and floated in PWA inconsistent with CBAR: BaBar: g KK = MeV 1/2 CBAR: g KK = MeV 1/2 need coupled channel analysis with D 0 K 0 PWA needs ~3% contribution from higher mass resonance tail (outside PS) assume f 0 (1400) ; uniform distribution worse what about a 0 (1450) ? _ BaBar DP projection D0K0SK+K-D0K0SK+K- (1020) 13 Stefan Spanier, PHP 2008 Workshop, JLAB I=1 Scalar a 0 (980) in B decays In 9 Y(4S) CLEO finds: [PRL 93 (2004) ] Main contribution from a 0 K 0 S ; also a 2 (1320)K 0 S, K*(892) , K 0 *(1430) B(D 0 K 0 0 ) = (1.05 0.16 0.14 0.10) % # ( ) events _ CLEO 14 Stefan Spanier, PHP 2008 Workshop, JLAB I=1/2 Scalar Data from: K - p K - + n and K - p K 0 - p NPB 296, 493 (1988) No data below 825 MeV/c 2 K Scattering LASS M K (GeV) Phase (degrees) M K (GeV) Most information on K - + scattering comes from the LASS experiment (SLAC, E135) K threshold use directly in production if re-scattering is small require unitarity approach LASS parameterization Disentangle I=1/2 and I=3/2 with K + + [NPB133, 490 (1978)] Pennington ChPT compliant 15 Stefan Spanier, PHP 2008 Workshop, JLAB I=1/2 Scalar LASS experiment used an effective range expansion to parameterize the low energy behaviour: : scattering phase q cot = + a: scattering length b: effective range q: breakup momentum Turn into K-matrix : K -1 = cot K = + and add a pole term (fits also pp annihilation data) Both describe scattering on potential V(r) ( a,b predicted by ChPT) Take left hand cuts implicitly into account Instead treat with meson exchange in t- ( ) and u-channel (K* ) [JPA:Gen.Phys 4,883 (1971), PRD 67, (2003)] only K 0 *(1430) appears as s-pole (K*) exchange important for S-waves in general % kappa ? 1 b q 2 a 2 ___ ______ a m g a b q 2 m 0 2 m 2 ___________ __________ _ 16 Stefan Spanier, PHP 2008 Workshop, JLAB I=1/2 Scalar D + (K - + ) + K system dominated by K*(892) Observe ~15% forward-backward asymmetry in K rest frame Hadronic phase of 45 o corresponds to I=1/2 K wave measured by LASS required by Watson theorem in semileptonic decay below inelastic threshold S-wave is modeled as constant (~7% of K*(892) Breit-Wigner at pole). a phase of 90 o would correspond to a kappa resonance, but Study semileptonic D decays down to threshold ! FOCUS Reconstructed events: ~27,000 D+D+ K-K- ++ c s W+W+ [PLB 621, 72 (2005)] [PLB 535, 43 (2002)] I=1/2 ? 17 Stefan Spanier, PHP 2008 Workshop, JLAB I=1/2 Scalar E791 K*(892) K*(1430) D+ K-++D+ K-++ #15090 Fit with Breit-Wigner (isobar model): ~138 % A ~89 % C 2 /d.o.f. = 0.73 2 /d.o.f. = 2.7 M = (797 19 42) MeV/c 2 eV c D+D+ K-K- ++ W+W+ ++ [PRL 89, (2002)] unitarity ++ ++ K-K- W+W+ 18 Stefan Spanier, PHP 2008 Workshop, JLAB I=1/2 Scalar Fit with Breit-Wigner + energy-independent fit to K S-wave (P(K*(892), K*(1680)) and D-waves (K* 2 (1430))act as interferometer) Model P- and D-wave (Beit-Wigner), S-wave A = a k e i k bin-by-bin (40) E791 Phase Compares well with BW Isobar fit S wave M(K ) / GeV/c 2 19 Stefan Spanier, PHP 2008 Workshop, JLAB I=1/2 Scalar E791 Quasi-two body K interaction (isobar model ) broken ? Watson theorem does not apply ? Isospin composition I=1/2 % I=3/2 in D decay same as in K K ? if not K threshold -75 o but differs from LASS elastic scattering |F I | A(s) e i s = F 1/2 (s) + F 3/2 (s), s = m K 2 F I (s) = Q I (s) e i I T 11 I (s) s s 0 I Q-vector approach with Watson: T 11 from LASS ( same poles ?) Constraint: Q smooth functions Adler zero s 0 I removed [Edera, Pennington: hep-ph/ ] big ! 20 Stefan Spanier, PHP 2008 Workshop, JLAB f 0 (980) (770) f 2 (1270) m 13 2 (GeV 2 ) Extract S-wave phase (s) from left-right asymmetry in f 2 (1270) F = a sin (s) e i( (s)+ ) Choose phase from 4 solutions ( o ) E791 fit ( (500)) E791: BW fit + (500) m = (478 24 17) MeV = (324 42 21) MeV FOCUS: use K-matrix A&S (no pole) [PLB 633, 167 (2006)] m( ) GeV I=0 Scalar Focus/E791 D+ -++D+ -++ E791 ~ 1680 events 21 Stefan Spanier, PHP 2008 Workshop, JLAB I=0 Scalar Au, Morgan, Pennington, Phys. Rev. D35, 1633 (1987) Anisovich, Sarantsev, Eur. Phys. A16, 229 (2003 ) 4 pole, 2 resonance 5 pole, 5 resonance I=0 S-wave parameterization (several on market) f 0 (980) f 0 (1500) from fits to data from scattering, pp annihilation, f 0 (980) : (988 i 23) MeV (1024 i 43) MeV describes ( 0 0 ) no (500) pole, but feature included also with t (u) channel (f 2,..) exchange [Li,Zou,Li:PRD 63,074003(2001)] (also I=2 phase shift) Coupled channel for pp-annihilation into 3 neutral PS, 3x3 K-matrix finds pole at low mass _ _ 22 Stefan Spanier, PHP 2008 Workshop, JLAB I=0 Scalar FOCUS f 0 (980) (1450) DS + - +DS + - + FOCUS(#1475) E791 (#848) S-wave 87% f 0 +f 0 (1370)+NR 90% K matrix,P vector* phase ~0, f MeV f 2 (1270) 10% 20% (1450) 6% 6% (770) 6% J/ FOCUS * not sensitive to Adler zero ss flavor tag _ c s _ s DSDS f 2 (1270) 23 Stefan Spanier, PHP 2008 Workshop, JLAB Charmless 3-body B Decays Mode Events (1/fb -1 ) D 0 K + K - K 0 ~140 B + K + Belle BABAR ~11 B + K + K - K + Belle ~8 B0 K+B0 K+ BABAR ~5 B 0 K 0 Belle 2005 ~3 B 0 K + K - K 0 BABAR 2005 ~2.5 B+KSKS K+B+KSKS K+ ~0.9 B0 K0SB0 K0S ~0.5 B0KSKS KSB0KSKS KS ~0.4 - Bodd # of K : penguin-dominated decays - large phase-space, limited number of events - Dalitz plot analyses at feasibility limit D0K+K-K0D0K+K-K0 B0K+K-K0B0K+K-K0 Dalitz Plot analysis 24 Stefan Spanier, PHP 2008 Workshop, JLAB Charmless B Decay Reconstruction Energy-substituted mass Energy difference Event shape Main background from continuum events: Some standard discrimination variables: * = e + e - CM frame Likelihood fit 25 Stefan Spanier, PHP 2008 Workshop, JLAB X(1500) Is bump at 1.5GeV really f 0 (1500)? - PDG: BF( f 0 (1500) )/BF( f 0 (1500)KK ) 4 K+K-KSK+K-KS K+K-KSK+K-KS Belle [PRD71] [hep-ex/ ] K+K+K-K+K+K- K+K+K-K+K+K- - hard to assign a small excess of events in K to f 0 (1500) -events assigned to f 0 (1370), f 2 (1270) - f 0 (1500) interferes with S- wave background constructively for KKK, destructively for K ? [Minkowski,Ochs,EPJC 39,71(2005)] B A B AR KSKS KSKS K+K+ K+K+ Belle [hep-ex/ ] [hep-ex/ ] f 0 (980) (770) 26 Stefan Spanier, PHP 2008 Workshop, JLAB Initial State Radiation ISR BaBar e + (3 GeV) e - (9 GeV) ISR ** e+e+ e-e- hadrons The radiative process effectively varies the CM energy of the e + e - collider access to processes at energies below Y(4S) If the ISR photon is detected in BaBar the hadrons are found in opposite direction Precision test of Standard Model (hadronic vacuum polarization) Low mass particle spectroscopy 27 Stefan Spanier, PHP 2008 Workshop, JLAB ISR BaBar The hard photon must be detected and well measured: - E > 3 GeV ( s < 4.68 GeV ) only directional information used in kinematic fit - Acceptance ~ 10 15 % polar angle range 30 o 150 o - BaBar runs an open trigger (lot of storage), high luminosity e.g. visible cross section: (e + e - + - ) ~ 1.2 pb pp PRD 73, (2006) PRD 70, (2004) , K + K - , PRD 71, (2005) K + K - K + K - , 2K + 2K - PRD 76, (2007) K + K - PRD 73, (2006) Most Recent results: K + K K S K K + K BaBar Preliminary arXiv: (submitted to PRD) BaBar Preliminary arXiv: (submitted to PRD) _ 28 Stefan Spanier, PHP 2008 Workshop, JLAB e+e- K + K - / KK K s K ( ) BaBar K S K + - E CM < m(J / ) Disentangle I=0 ( -like), I=1 ( -like) components in Dalitz plot Split at E CM = 2GeV into K*(892)K and K* 2 (1430)K dominated region From interference find I=0 and I=1 K*K Fit to K*(892)K, K + K - 0 / ( , no- (symmetric DP)), 0, and 4.6 232fb -1 B A B AR 29 Stefan Spanier, PHP 2008 Workshop, JLAB e+e- / BaBar OZI suppressed ? I G =1 + I G =0 - (1680) M= 1710 MeV = 325 MeV M= 2125 MeV = 60 MeV Mass fits simultaneously to (e+e- K*K) `` ``` 2.5 3.3 +K + K - : m=1570 =145 == C(1480) ? or (1700) ? : consistent with dip in multi-pion data! B A B AR 30 Stefan Spanier, PHP 2008 Workshop, JLAB Evidence for X(2175) Very rich substructure K * (892), K 1 (1270), K 2 *0 (1430), K 1 (1400) Select f 0 (980) + (1020) from invariant mass spectra PS model (+10% ) 232fb -1 ? Phys.Rev.D B A B AR 31 Stefan Spanier, PHP 2008 Workshop, JLAB Study of Charmonia at B-Factories Colour-suppressed (Y(4S)) b c decay Predominantly from B-meson decays e + e - annihilation/Initial State Radiation (ISR) e+e- collision below nominal c.m. energy J PC = 1 -- Double charmonium production Typically one J/y or y, plus second ccbar state Two-photon production Access to C = +1 states 32 Stefan Spanier, PHP 2008 Workshop, JLAB ISR Study of Charmonia BaBar discovers peaks in Y(4260) J/ + - and Y(4320) S 673fb fb fb -1 arXiv:0707:3699 PRL 95, (2005)PRL 98, (2007) States confirmed by Belle, in addition to claims for two others Too many J PC = 1 No evidence for Y D (*) D (*) from BaBar or Belle (no ) difficult to accommodate as cc - 33 Stefan Spanier, PHP 2008 Workshop, JLAB Study of Charmonia < 2004 34 Stefan Spanier, PHP 2008 Workshop, JLAB The D SJ States - strange charmed mesons D s0 *(2317) D s1 (2460) D sJ *(2860) X(2690) D sJ (2700) S wave P wave D wave * D s0 *(2317) +, Apr. 2003: unexpected observation of a narrow resonance in BaBar D s1 (2460) +, May 2003: CLEO, BaBar observed a new narrow resonance D sJ *(2860) +, Jul. 2006: new state discovered by BaBar D sJ (2700) +, Jul. 2006: new state discovered by Belle (== X(2690) ? ) X(2690) +, Jul. 2006: broad enhancement seen in BaBar D s *, D s1 (2536) +, D s2 (2573) + : well known, but J P only inferred (not measured!) (2112) 35 Stefan Spanier, PHP 2008 Workshop, JLAB Summary B-Factories are a rich source of mesons in many production modes 36 Stefan Spanier, PHP 2008 Workshop, JLAB D s0 *(2317) and D s1 (2460) Update Discovered 4 years ago in e + e - cc events ; subsequently observed in B decays D s0 *(2317) and D s1 (2460) very well established and known experimentally Masses and tight upper limits on widths J P : 0 + for D s0 *(2317) and 1 + for D s1 (2460) decay modes and branching fractions Interpretation of these new states still unclear! One possibility: identify these 2 states as the 0 + and 1 + cs states However strong difficulties within the potential model Other possibilities 4 quark states? DK molecule? D atom? Chiral symmetry? Belle: Phys. Rev. Lett. 91 (2003) BaBar: Phys. Rev. D74 (2006) Belle: Belle-Conf-0461 (2006) BaBar: Phys. Rev. D74 (2006) 37 Stefan Spanier, PHP 2008 Workshop, JLAB D sJ *(2860): Another New State Reconstruct from cc continuum: e + e - D 0 (K - +,K - + 0 ) K + X and e + e - D + (K - + + ) K 0 s X New state at 2860 MeV/c 2 ! (fit with a Breit-Wigner) Bump at 2690 MeV/c 2 ? (better fit with a Gaussian than a Breit-Wigner) 240 fb -1 p * > 3.5 GeV/c 2 D 0 (K - + )K + D 0 (K - + 0 )K + D + (K - + + )K 0 s 38 Stefan Spanier, PHP 2008 Workshop, JLAB D sJ *(2860) and X(2690) Sum of 3 modes BaBar: Phys. Rev. Lett. 97 (2006) D sJ *(2860) X(2690) Combining the 3 modes M = ( 1.5 5.0) MeV/c 2 = (47 7 10) MeV J P = 0 +, 1 -, 2 +, Final state is DK, i.e. two pseudoscalars Interpretation of D sJ *(2860)? Radial excitation of D s0 *(2317)? hep-ph/ cs with J P = 3 - ? hep-ph/ cs with J P = 0 + ? hep-ph/ Another structure at 2690 MeV/c 2 ? M = (2688 4 3) MeV/c 2 = (112 7 36) MeV Needs confirmation by other experiments or in other channels bkg subtracted m(DK) GeV/c 2 39 Stefan Spanier, PHP 2008 Workshop, JLAB New resonance decaying to D 0 K + discovered by Belle in B + D 0 (D 0 K + ) : D sJ (2700) Same resonance as seen by BaBar in continuum, X(2690)? Mass and width consistent, same decay mode Study of B D ( * ) D ( * ) K decays in BaBar Construct 8 DK + 8 D*K invariant masses Enhancement observed around 2700 MeV/c 2 in DK and D*K Full Dalitz plot analysis ongoing Summing all 8 D*K modes D s1 (2536) Summing all 8 DK modes Background (generic MC) Phase space 347 fb -1 Background (generic MC) D sJ (2700) - a Different State ? Belle: hep-ex/