On Behalf of the BaBar Collaboration Charm Semileptonic Decays A. Oyanguren (IFIC – Valencia) On Behalf of the BaBar Collaboration Heavy Quarks and Leptons 2012, Praga 11-May-2012

Outline  Motivation  Experiments and methods  Pseudoscalar decays: D → P (P=K,,…)  Vector decays: D(s) → V (V=K*,, , …)  S-wave systems  Conclusions HQL 2012 A. Oyanguren 2

Motivation  Understand (by measuring) non-perturbative QCD → Expressed in terms of form factors (for semileptonic decays) → Computed by Lattice-QCD Outcome:  Validation for the B sector (avoiding fake New Physics hints!)  Study of JP=0+ states (S-wave systems) in a non-hadronic environment HQL 2012 A. Oyanguren 3

Experiments and data: >1ab-1 BES III 3 fb-1 550 fb-1 CLEOc 7 fb-1 cc ~1.3 nb DD ~6 nb CLEOc 7 fb-1 CLEO III 0.82 fb-1 ~1M cc +BeO HQL 2012 A. Oyanguren 4

Methods  FOCUS:  CLEOc & BES III :  BaBar:  BELLE: @ (3770)→DD Reconstruct the D*→D, and the D in the semimuonic channel (or D→K)  CLEOc & BES III : - Tagged: Full reconstruction: one D in a hadronic channel, the other in the semileptonic channel (only the  is missing) - Untagged (CLEOc): lepton + hadron from the D, Emiss of the event = E CLEOc @ (4s) (cc)  BaBar: Partial reconstruction of cc events, the D*→D and the D in the Ke channel (or the D(s)→Vee ). D(s) direction and E from the rest of the event (untagged)  BELLE: Full reconstruction of cc events including hadronization particles, one D into hadrons, the other in the sl channel, only  is missing (tagged) BaBar HQL 2012 A. Oyanguren 5

D→P f+K(q2) f+(q2) Vcs, Vcd HQL 2012 A. Oyanguren 6 Known angular distribution  sin2() Cabibbo favoured D→K and suppressed D→ Vcs, Vcd  Only one form factor in the differential decay width f+(q2): q2=(pD – pP )2 = (p + p)2  New Lattice QCD computations: f+K(q2) f+(q2) FNAL and MILC arXiv:1111.5471 FNAL and MILC arXiv:1111.5471 HQL 2012 A. Oyanguren 6

Form factors HQL 2012 A. Oyanguren 7 Simple pole Modified pole ISGW2 Model prediction: D→K mD*s = 2.112 GeV/c2 D→ mD* = 2.010 GeV/c2 Modified pole Lattice computation: D→K apole= 0.50(4)(7) D→ apole= 0.44(4)(7) ISGW2 Model prediction: D→K, D→ aI ~ 0.1 GeV-2 Series expansion No model predictions r1 = a1/a0 r2 = a2/a0 t  q2 |z| << 1 HQL 2012 A. Oyanguren 7

D→P @ B-factories: (Analysis with ~ 1/7 BaBar stat.) (Analysis with ~ ¼ Belle stat.) PRD 76 (2007) 052005 PRL 97 (2006) 061804 126  12 281 fb-1 106  13 73980 D0K-l+ mn² / GeV² = (mD*-mD0) data HQL 2012 A. Oyanguren 8

D→P @ threshold: HQL 2012 A. Oyanguren 9 -  NEW results from BES III (1/3 total stat.): D0 K+ ’’ 0.9fb-1 BES III Preliminary D0 e+ e -  CLEO –c also reconstruct the D+ →(,’)ee using tagged and untagged (GR) methods PRD 84 (2011) 032001 0.9fb-1 BES III Preliminary CLEO –c 818 pb-1 HQL 2012 A. Oyanguren 9

D→K HQL 2012 A. Oyanguren 10  Results on form factors: Simple pole Modified pole arXiv:0906.2498 mpole far from theoretical Expectations mDs* =2.112 GeV → High precision measurements → Agreement ? pole<1 as expected Contributions from other states HQL 2012 A. Oyanguren 10

D→K HQL 2012 A. Oyanguren 11 Series expansion  Results on form factors: Physics interpretation? Provided by L. Gibbons (HFAG) HQL 2012 A. Oyanguren 11

D→ HQL 2012 A. Oyanguren 12  Results on form factors: Simple pole Modified pole mpole far from theoretical expectations mD* =2.010 GeV pole<1 as expected Info from contributions from other states Series expansion Provided by L. Gibbons (HFAG) HQL 2012 A. Oyanguren 12

D→P HQL 2012 A. Oyanguren 13  Form factor normalization: D→K D→ (HFAG prel.) Experimental accuracy below 1% ! D→ (HFAG prel.) Good agreement between lattice and experiments HQL 2012 A. Oyanguren 13

D→K The decay rate depends on 5 variables: mV, q2,  v , l ,  For vector decays (D→K*) two form factor ratios are introduced: A1(q2), A2(q2), and V(q2) shapes: single pole or Fajfer and Kamenik PRD 72, 034029 (2005)  Sensitive to the K S-wave (JP=0+ ) @ Babar: PRD 83 (2011) 072001 347fb-1 HQL 2012 A. Oyanguren 14

D→K HQL 2012 A. Oyanguren 15  Form factors mesurement:  Detailed mesurement of the D→K channel: HQL 2012 A. Oyanguren 15

D→K HQL 2012 A. Oyanguren 16 @ CLEO-c: Measure the q2 dependence of helicity form factors in D→K PRD81,112001 (2010)  Comparison with BaBar results: PRD 83 (2011) 072001 Form factor component Good agreement HQL 2012 A. Oyanguren 16

K S-wave HQL 2012 A. Oyanguren 17 •S-wave contribution @ BaBar: BaBar PRD 83 (2011) 072001 BaBar •Same phase variation in D→K decays and Kπ scattering in the elastic regime (Watson’s theorem) → BaBar and LASS agree well • Helpful to understand the effect of the spectator π in D+ →K- π+ π+ HQL 2012 A. Oyanguren 17

D→ HQL 2012 A. Oyanguren 18 @ CLEOc : arXiv:1112.2884 [hep-ex] - With full reconstruction also measure the suppressed decay De () 818 pb-1 CLEOc In agreement with Fajfer and Kamenik HQL 2012 A. Oyanguren 18

Ds→  @ BaBar same reconstruction technique as previous analyses ( ~1/2.5 BaBar stat.) D- Ds +  e+ K+ K- PRD78 (2008) 051101 (RC) Determination of form factors: 214 fb-1 BaBar In agreement with Lattice: HQL 2012 A. Oyanguren 19

KK S-wave BaBar HQL 2012 A. Oyanguren 20  First evidence of a S-wave: Small contribution (0.22% in the  region) PRD78 (2008) 051101 (RC) BaBar BaBar Interference with  214 fb-1 Important for s measurements: → Expected contribution of the S-wave in the Bs→J/ KK channel below 1% (in the same m). This in agreement with D0, CDF and LHCb observations  For D→, HQL 2012 A. Oyanguren 20

Ds→f0 HQL 2012 A. Oyanguren 21 @ CLEOc (4176 MeV): PRD 80 (2009) 052009 @ CLEOc (4176 MeV): - D→KK and D→ using the full reconstruction method In addition to the , they also observe the f0 (980) (→ ) (0+ state) 600 pb-1 CLEO-c The ratios of the decay rates at q2=0: Simple pole BaBar form factors Important to measure CPV in the Bs→J/ f0 channel HQL 2012 A. Oyanguren 21

Conclusions  Many results in different channels  New data coming @ BESIII  Only partial data analyzed at B-factories  |Vcs|f+K(0) accuracy at 1%  |Vcd|f+(0) accuracy at 2%  Precise Lattice results to be compared with, in agreement with experiments  Important informations on the S-wave systems HQL 2012 A. Oyanguren 22

and to my 5-year-old daughter Maia for the background picture Thank you Special thanks to P. Roudeau and L. Gibbons for the averages and to my 5-year-old daughter Maia for the background picture