Experimental review of three-body hadronic B-meson decays Rafael - PowerPoint PPT Presentation

UNIVERSITÄT ZÜRICH Experimental review of three-body 
 hadronic B-meson decays Rafael Silva Coutinho University of Zurich On behalf of the LHCb experiment (including results from BaBar and Belle) June 06 th , 2016 Flavour Physics and CP violation (FPCP) 2016

Overview of recents 3-body decays results This talk covers some recent publications from hadronic three-body decays Introduction to three-body decays analyses B decays to open charm, i.e. B → Dhh Ê channels [Dalitz-plot analysis, spectroscopy] Status/issues foreseen for CPV measurements in charmless three-body charged decays [Large CP violation seen in B ± → h ± h ∓ h ± decays] Final states involving K 0S and/or π 0 Ês [ i.e. Β 0(s) → Κ 0S h ± h’ ∓ , Β 0(s) → h + h - π 0 , Β + → Κ 0S h + h 0 decays] b -baryon and Β +c decays [Searches and CP violation measurements] 2 R. Coutinho (UZH) - FPCP 2016

Dalitz plot analysis Technique named after Richard Dalitz (1925-2006) Spin/parity determination of the known τ / θ particles in its decay products „On the analysis of tau-meson data and the nature of the tau-meson.‰ R. H. Dalitz, Phil. Mag. 44 (1953) 1068 „I visualise geometry better than numbers‰ Richard Dalitz Scatter-plot visualisation can be interpreted as: Matrix element is constant, i.e. DP uniformly populated with events Non-uniform distributions gives information about the dynamics SLAC-PUB-5151 Interference patterns between intermediate states can be studied and parametrised „A work of art‰ - gift from B. Ritcher, W. Panofsky, S. Drell, D. Leith, D. Aston, W. Dunwmoodie and B. Ratcliff 3 R. Coutinho (UZH) - FPCP 2016

Dalitz plot analysis features Toy simulation using Laura++ package: Intensity along bands indicates magnitude https://laura.hepforge.org and the spin of the given resonance ] 4 3 c D 0 → K 0 S π + π − / 2 ) [GeV 10 2.5 (Non realistic simulation) ( m 1 + m 2 ) 2 + π 2 0 S ( M − m 1 ) 2 K 8 ( 2 m 1.5 2 ( m 23 ) max m 23 (GeV 2 ) 1 6 ( M − m 3 ) 2 0.5 0.5 1 1.5 2 2.5 3 2 4 0 − 2 m 2 ( K ) [GeV / c 4 ] π S 2 ( m 23 ) min Amplitude analysis can access: ( m 2 + m 3 ) 2 2 Relative phases between states 0 Sensitivity to CP violating effects 0 1 2 3 4 5 2 m 12 ( Ge V 2 ) Resolve ambiguities in weak phases Particle Data Group Collaboration PRD 86 (2012) 010001 Hadron spectroscopy 4 R. Coutinho (UZH) - FPCP 2016

Dalitz plot analysis - Isobar Model A possibility is to perform an „Isobar Model‰, in which the total amplitude is approximated as coherent sum of quasi-two-body contributions: Strong dynamics CP violating CP conserving N X A ( m 2 ij , m 2 c l F l ( m 2 ij , m 2 jk ) = jk ) l =1 c l : complex coefficients describing the relative magnitude and phase of the different isobars F l : dynamical amplitudes that contain the lineshape and spin-dependence of the hadronic part F l ( L, m 2 ij , m 2 jk ) = R l ( m 2 ij ) × X L ( | ~ p | r ) × X L ( | ~ q | r ) × T l ( L, ~ q ) p, ~ Resonance mass term Barrier factors - p , q : momenta Angular probability (e.g. Breit – Wigner) of bachelor and resonance distribution Many observables can be accessed: Re(c i ) and Im(c i ) or |c i | and arg(c i ); or derived quantities such as BF and A CP 5 R. Coutinho (UZH) - FPCP 2016

B decays to open charm, i.e. B → Dhh Ê channels Dalitz-plot analyses ( e.g. spectroscopy and CKM angle measurements) Charm and charm-strange spectroscopy [PRL 113, 162001 (2014), PRD 90, 072003 (2014)] [PRD 91, 092002 (2015)] [PRD 92, 032002 (2015)]

D s(**) spectroscopy - B 0s → D 0 K - π + PRD 89, 074023 (2014) Spectroscopy of strange-charm states has been Stephen Godfrey, Ian T. Jardine reinvigorated due to recent observations of D s0* (2317) and D s1 (2460) 3323' 3311 3306 3218' 3208 3154 3193 3190 3298 3200 3186 3048 3038' DP analysis of B 0s → D s**- (D 0 K - ) π + 3005 2926' 2917 2899 3018 Mass (MeV) 2900 2800 2673 2732 2592 2556' D ∗ sJ (3040) − 2484 2549 2400 D ∗ sJ (2860) − Some discrepancies 2129 D s Mass Spectrum have been seen 1979 D ∗ s 1 (2700) − 2000 between predicted and measured values D ∗ s 2 (2573) − 1600 3 F 2 F 3 1 S 0 3 S 1 3 P 0 P 1 3 P 2 3 D 1 D 2 3 D 3 3 F 4 D s 1 (2536) − D s 1 (2460) − D ∗− D s* and D s0* (2317) are too light to decay to D 0 K - s Neither can states with unnatural spin-parity D ∗ s 0 (2317) − D s (J P = 0 - , 1 + , 2 - , etc) D s2* (2573), D s1* (2700) and D sJ* (2860) are possible 7 R. Coutinho (UZH) - FPCP 2016

Dalitz plot analysis of B 0s → D 0 K - π + PRL 113, 162001 (2014) PRD 90, 072003 (2014) Analysis performed with ~11K signal events and purity of 87% Signal region: µ2.5 σ around nominal mass Backgrounds due to Combinatorial (7.3%), B 0 → D (*)0 ππ (2.8%) and Λ 0 b → D (*)0 p π (2.3%) is considered for the Dalitz plot fit ] ) 4 2 /c 12 Candidates / (7 MeV/c 2500 LHCb LHCb 2 ) [GeV Data (a) 10 2000 Full fit 0 8 B signal + s π 1500 Combinatorial bkg. − K 6 0 − 0 D ( B K + → π 2 m 1000 * 0 − 0 D 4 B K + → π s ( )0 * 0 − D + B → π π 500 2 ( )0 * 0 D p Λ + → π b 0 0 5 10 15 20 25 5200 5400 5600 5800 0 − 2 4 0 m 2 ( D K ) [GeV /c ] − 2 D m ( K + ) [MeV/c ] π 8 R. Coutinho (UZH) - FPCP 2016

Dalitz plot fit results PRL 113, 162001 (2014) PRD 90, 072003 (2014) 400 ) ) 2 2 Candidates / (13 MeV/c ¯ Candidates / (9 MeV/c K ∗ (892) 0 LHCb LHCb 350 500 (a) (b) 300 400 250 D ∗ s 2 (2573) D ∗ sJ (2860) ¯ 0 , 2 (1430) 0 K ∗ 300 200 150 200 100 100 50 0 0 0.5 1 1.5 2.4 2.6 2.8 3 3.2 − 0 − 2 2 + m ( K ) [GeV/c ] D π m ( K ) [GeV/c ] ) ) 2 200 2 Candidates / (5 MeV/c Candidates / (1.5 MeV/c 45 LHCb LHCb 180 40 (c) (d) 160 35 140 D ∗ s 2 (2573) D ∗ sJ (2860) 30 120 25 100 20 80 15 60 10 40 5 20 0 0 2.5 2.55 2.6 2.65 2.75 2.8 2.85 2.9 2.95 3 0 0 − − 2 2 D D m ( K ) [GeV/c ] m ( K ) [GeV/c ] 9 R. Coutinho (UZH) - FPCP 2016

Dalitz plot fit results - helicity projections PRL 113, 162001 (2014) PRD 90, 072003 (2014) 160 Candidates / 0.04 Candidates / 0.04 LHCb (b) 350 LHCb (b) 140 − 0 − 2 2 + 0.8 < m ( K π ) < 1.0 GeV/c 300 2.49 < m ( D K ) < 2.65 GeV/c 120 Vector 250 100 Tensor 200 80 150 60 100 40 50 20 0 0 -1 -0.5 0 0.5 1 -1 -0.5 0 0.5 1 − 0 − + cos ( K ) θ π cos ( D K ) θ Candidates / 0.04 Candidates / 0.04 70 35 LHCb (d) LHCb (d) 60 − 0 2 − 30 2 1.4 < m ( K π + ) < 1.5 GeV/c 2.77 < m ( D K ) < 2.91 GeV/c ?? 50 25 Scalar + Tensor 40 20 30 15 20 10 10 5 0 0 -1 -0.5 0 0.5 1 -1 -0.5 0 0.5 1 − 0 − + cos ( K ) θ π cos ( D K ) θ 10 R. Coutinho (UZH) - FPCP 2016

D sJ* (2860) - state PRL 113, 162001 (2014) PRD 90, 072003 (2014) Several spin hypotheses have been investigated for the D sJ* (2860) - χ 2 =47 . 3 , 214 , 150 . 0 N bin = 50 Candidates / 0.04 Two states [ D s1* (2860) - , D s3* (2860) - ] Data 50 are required in the region 2.86 GeV/c 2 LHCb spin-1 + spin-3 (each with a significance of 10 σ ) 40 spin-1 30 spin-3 1 st observation of a heavy flavoured spin-3 resonance and 1 st time a spin-3 state seen 20 to be produced in B decay 10 √ Spin hypothesis ∆ NLL 2 ∆ NLL Masses and widths 0 1+3 0 — -1 -0.5 0 0.5 1 0 141.0 16.8 2862 57 0 − D cos ( K ) θ 0+1 113.2 15.0 2446 250 2855 96 0+2 155.1 17.6 2870 61 2569 17 0+3 105.1 14.5 2415 188 2860 52 The presence of the state D s3* (2860) has 1 156.8 17.7 2866 92 1+2 138.6 16.6 2851 99 3134 174 been independently confirmed in studies 2 287.9 24.0 3243 81 of pp → D *(+,0) K 0,+ X (LHCb) 2 365.5 27.0 2569 17 2+3 131.2 16.2 2878 12 2860 56 [JHEP 02 (2016) 133] 3 136.5 16.5 2860 57 11 R. Coutinho (UZH) - FPCP 2016

Charm spectroscopy at LHCb PRD 92, 032002 (2015) PRD 91, 092002 (2015) Recent measurements of e + e - / 𝑞𝑞 indicated B − → D + K − π − the presence of higher excited states 5 Initial investigation of angular (both BaBar and LHCb) pull 0 moments to guide the modelling -5 6000 3 10 × / (0.054 GeV) 4000 LHCb 15 60000 (g) 10 2000 Candidates / (4 MeV) 5 0 0 40000 〉 6 2500 3000 P -5 〈 LHCb -10 No spin > 2 structure JHEP 09 (2013) 145 -15 20000 2 3 4 + − m ( ) [GeV] D π B 0 → ¯ D 0 π + π − 0 2200 2400 2600 2800 3000 0 + m(D ) [MeV] π Two different DP fit framework: States D *J (2650) and D *J (2760) Isobar model and K-matrix parametrisation of the S-wave seen to decay to D π 12 R. Coutinho (UZH) - FPCP 2016

DP analysis of B - → D + K - π - , B 0 → D 0 π + π - PRD 92, 032002 (2015) PRD 91, 092002 (2015) B − → D + K − π − B 0 → ¯ D 0 π + π − Candidates / (40 MeV) ) LHCb (b) Data 4 150 LHCb /c 2 Isobar fit Events / ( 0.1 GeV 2 10 (a) * D (2760) J * 100 Other D − + π π 10 Background 50 1 0 2 3 4 5 7 8 9 10 + - m( D ) [GeV] π 0 − 2 2 4 m( D ) [GeV /c ] π Data strongly (10 σ ) favours spin-3 Data favours spin-1 hypothesis for the state D *J (2760) 0 (other assignments are assignment to the state D *J (2760) - rejected with > 6 σ ) No evidence for an additional spin-1 13 R. Coutinho (UZH) - FPCP 2016