Angular analyses at CMS Alessio Boletti 1 on behalf of the CMS collaboration Rare B Decays workshop Apr 18th, 2016 1INFN & Universita‘ di Padova A. Boletti Angular analyses at CMS Rare B Decays 2016 1 / 15
Introduction Angular analyses at CMS A. Boletti Angular analyses at CMS Rare B Decays 2016 2 / 15
Introduction Angular analyses at CMS B + → K ∗ + µµ analysis ongoing too few events to measure complete P i set aiming at F L , A FB and d BR / d q 2 B + → K + µµ analysis ongoing scalar K meson: only A FB and d BR / d q 2 measured Λ b → Λ µµ analysis started A. Boletti Angular analyses at CMS Rare B Decays 2016 3 / 15
Introduction Angular analyses at CMS B 0 → K ∗ 0 µµ with reduced parametrization public paper [Phys. Lett. B 753 (2016) 424-448] F L , A FB and d BR / d q 2 measured B 0 → K ∗ 0 µµ with complete parametrization analysis ongoing aiming the measurement of P ′ 5 no approved results A. Boletti Angular analyses at CMS Rare B Decays 2016 4 / 15
B 0 → K ∗ µµ B 0 → K ∗ (892) 0 µ + µ − K + ϕ K + μ − μ − θ K P B 0 P B 0 θ l μ + μ + μμ rest frame π − π − K *0 rest frame Four-particle final state topology three decay angles: θ K , θ l , φ the square of dimuon invariant mass: q 2 A. Boletti Angular analyses at CMS Rare B Decays 2016 5 / 15
B 0 → K ∗ µµ CP-averaged angular distribution 3D angular distribution with 8 free parameter challenging fit convergence problems with few events A. Boletti Angular analyses at CMS Rare B Decays 2016 6 / 15
B 0 → K ∗ µµ CP-averaged angular distribution Integrating out the φ angle no problems with efficiency: quite flat in φ measurement of F L and A FB A. Boletti Angular analyses at CMS Rare B Decays 2016 7 / 15
B 0 → K ∗ µµ S-wave component d 3 Γ 1 d cos θ K d cos θ l d q 2 = 9 �� 2 3 F S + 4 � (1 − cos 2 θ l ) 3 A S cos θ K Γ 16 � 2 F L cos 2 θ K (1 − cos 2 θ l ) + (1 − F S ) �� + 1 2(1 − F L )(1 − cos 2 θ K )(1 + cos 2 θ l ) + 4 3 A FB (1 − cos 2 θ K ) cos θ l Also K π couple produced in S-wave configuration F S , fraction of S-wave K π A S , S-P waves interference term Small contribution, but need to be included in the PDF A. Boletti Angular analyses at CMS Rare B Decays 2016 8 / 15
B 0 → K ∗ µµ Data samples Dataset 2012 data: 20 . 5 fb − 1 at √ s = 8 TeV Signal and control channels naturally defined in q 2 bins 7 signal bins (1–19 GeV) B 0 → K ∗ J /ψ control channel ( | q − m J /ψ | < 3 σ q ) B 0 → K ∗ ψ ′ control channel ( | q − m ψ ′ | < 3 σ q ) Flavour mistag No PID: no difference between pion and kaon B 0 flavour determined with the K π invariant mass 12–14% of events mistagged their contribution considered in the PDF, with flipped angles A. Boletti Angular analyses at CMS Rare B Decays 2016 9 / 15
B 0 → K ∗ µµ Efficiency 2D efficiency function computed on MC simulation 3rd degree (cos θ K ) x 5th degree (cos θ K ) polynomial fitted to binned efficiency both for correctly and wrongly tagged events efficiency function multiplies the fit PDF A. Boletti Angular analyses at CMS Rare B Decays 2016 10 / 15
B 0 → K ∗ µµ Signal yields − 1 − 1 − 1 CMS CMS CMS 20.5 fb (8 TeV) 20.5 fb (8 TeV) 20.5 fb (8 TeV) Events / ( 0.028 GeV ) 35 2 : 1.00 − 2.00 GeV 2 Data Events / ( 0.028 GeV ) 2 : 2.00 − 4.30 GeV 2 Data Events / ( 0.028 GeV ) 2 : 4.30 − 6.00 GeV 2 Data q q q Total fit Total fit 50 Total fit ± ± ± Signal yield: 84 11 60 Signal yield: 145 16 Signal yield: 118 15 Corr. tag sig. Corr. tag sig. Corr. tag sig. 30 Mistag sig. Mistag sig. Mistag sig. 50 40 Background Background Background 25 40 30 20 30 15 20 20 10 10 5 10 0 0 0 5 5.1 5.2 5.3 5.4 5.5 5 5.1 5.2 5.3 5.4 5.5 5 5.1 5.2 5.3 5.4 5.5 + − + − + − + − + − + − Κ π µ µ Κ π µ µ Κ π µ µ m ( ) (GeV) m ( ) (GeV) m ( ) (GeV) − 1 − 1 CMS 20.5 fb (8 TeV) CMS 20.5 fb (8 TeV) 2 − 2 Data 2 − 2 Data Events / ( 0.028 GeV ) : 6.00 8.68 GeV Events / ( 0.028 GeV ) : 10.09 12.86 GeV 100 q 140 q Total fit Total fit Signal yield: 253 ± 21 Signal yield: 362 ± 25 Corr. tag sig. Corr. tag sig. Signal 120 80 Mistag sig. Mistag sig. Background Background 100 60 Mistagged signal 80 60 40 Background 40 20 20 0 0 5 5.1 5.2 5.3 5.4 5.5 5 5.1 5.2 5.3 5.4 5.5 + − + − + − + − Κ π µ µ Κ π µ µ m ( ) (GeV) m ( ) (GeV) − − CMS 1 CMS 1 20.5 fb (8 TeV) 20.5 fb (8 TeV) 2 − 2 Data 2 − 2 Data Events / ( 0.028 GeV ) : 14.18 16.00 GeV Events / ( 0.028 GeV ) : 16.00 19.00 GeV q q 70 80 ± Total fit ± Total fit Signal yield: 227 18 Signal yield: 239 18 A total of more than 1400 Corr. tag sig. Corr. tag sig. 60 70 Mistag sig. Mistag sig. signal events Background Background 60 50 50 Clear yields in all the q 2 bins 40 40 30 30 20 Same yields in the ongoing 20 10 10 full angular analysis 0 0 5 5.1 5.2 5.3 5.4 5.5 5 5.1 5.2 5.3 5.4 5.5 Κ + π − µ + µ − Κ + π − µ + µ − ( ) (GeV) ( ) (GeV) m m A. Boletti Angular analyses at CMS Rare B Decays 2016 11 / 15
B 0 → K ∗ µµ Fit strategy Unibinned likelihood fit performed in each q 2 bin Fitted m ( K πµµ ), cos θ K , cos θ l Background shapes from fit to m ( B 0 ) sidebands Signal m ( B 0 ) shapes and fraction of mistagged events from MC Example of fit in special bin 1 < q 2 < 6 GeV 2 − − − CMS 1 140 CMS 1 140 CMS 1 20.5 fb (8 TeV) 20.5 fb (8 TeV) 20.5 fb (8 TeV) − Data Events / ( 0.1 ) − Data Events / ( 0.1 ) − Data Events / ( 0.028 GeV ) 2 : 1.00 6.00 GeV 2 2 : 1.00 6.00 GeV 2 2 : 1.00 6.00 GeV 2 140 q q q Total fit Total fit Total fit ± Signal yield: 346 24 120 120 Corr. tag sig. Corr. tag sig. Corr. tag sig. 120 Mistag sig. Mistag sig. Mistag sig. 100 100 Background Background Background 100 80 80 80 60 60 60 40 40 40 20 20 20 0 0 0 5 5.1 5.2 5.3 5.4 5.5 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 + Κ π − µ + µ − θ θ m ( ) (GeV) cos( ) cos( ) Κ l A. Boletti Angular analyses at CMS Rare B Decays 2016 12 / 15
B 0 → K ∗ µµ Systematic uncertainties A. Boletti Angular analyses at CMS Rare B Decays 2016 13 / 15
B 0 → K ∗ µµ Results − − 1 1 CMS CMS 20.5 fb (8 TeV) 20.5 fb (8 TeV) 1 1 L FB F Data A 0.9 0.8 〈 〉 SM, LCSR 0.8 0.6 〈 〉 SM, Lattice 0.7 0.4 0.6 0.2 0.5 0 0.4 -0.2 0.3 -0.4 Data 0.2 -0.6 〈 〉 SM, LCSR 0.1 〈 〉 -0.8 SM, Lattice 0 -1 2 4 6 8 10 12 14 16 18 2 4 6 8 10 12 14 16 18 2 2 2 2 (GeV ) (GeV ) q q − Shorter error bars: statistical only CMS 1 20.5 fb (8 TeV) 12 ) 2 Data − GeV 〈 〉 SM, LCSR 10 Blue boxes: SM predictions, 〈 〉 SM, Lattice × 8 − form-factors with light-cone sum rules 8 (10 at low q 2 and extrapolated to high q 2 2 q / d 6 Β d [JHEP 09 (2010) 089, JHEP 02 (2013) 010] 4 2 Red boxes: SM predictions, form-factors by lattice calculations 0 2 4 6 8 10 12 14 16 18 2 2 (GeV ) q [Phys. Rev. D 89 (2014) 094501] A. Boletti Angular analyses at CMS Rare B Decays 2016 14 / 15
B 0 → K ∗ µµ Conclusions No CMS P i results public yet Complex analysis with 4D fit Many systematic uncertainties to be calculated But new results is arriving CMS P ′ 5 measurement B + angular analyses A. Boletti Angular analyses at CMS Rare B Decays 2016 15 / 15
Backup A. Boletti Angular analyses at CMS Rare B Decays 2016 15 / 15
Backup Table of results A. Boletti Angular analyses at CMS Rare B Decays 2016 15 / 15
Backup 7+8 TeV combination vs. other experiments 1 1 L FB F A 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0 0 -0.2 CMS (7, 8 TeV) CMS (7, 8 TeV) -0.2 LHCb -0.4 LHCb BaBar BaBar -0.4 -0.6 Belle Belle -0.6 -0.8 CDF CDF -0.8 -1 0 2 4 6 8 10 12 14 16 18 0 2 4 6 8 10 12 14 16 18 2 2 2 2 (GeV ) (GeV ) q q 12 ) 2 CMS (7, 8 TeV) − GeV LHCb 10 BaBar × Belle 8 − (10 8 CDF 2 q / d 6 Not present the last LHCb result Β d 4 2 0 0 2 4 6 8 10 12 14 16 18 2 2 (GeV ) q A. Boletti Angular analyses at CMS Rare B Decays 2016 15 / 15
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