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Outline 2 Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

KEKB and Belle 3 Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

Integrated luminosities 4 Dr. Prafulla Kumar Behera, IIT Madras Belle recorded more than 1 ab -1 ! 9 th June 2015 fb X 10 6 BB pairs

5 Dr. Prafulla Kumar Behera, IIT Madras Amplitudes and Phases in the Weak Interaction N. Cabibbo M.Kobayashi T.Maskawa L. Wolfenstein 9 th June 2015

6 Dr. Prafulla Kumar Behera, IIT Madras Three Angles: φ 1, φ 2, φ 3 ICHEP 2014: New Belle result on π 0 π 0 Unitarity implies that the weak couplings and phases form a triangle in the complex plane. B 0  π - π + B 0  Ψ K s,Ψ K L B -  D CP K - Big Questions: Are determinations of angles consistent with determinations of the sides of the triangle ? Are angle determinations from loop and tree decays consistent ? 9 th June 2015

Time- dependant CP Asymmetrie in decays to CP eigenstates 7 Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015 ϕ1ϕ1 ϕ2ϕ2

Measuring the CP parameters S and A 8 Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

9 ~25 Institutes in India, about 100 collaborators Dr. Prafulla Kumar Behera, IIT Madras Measurement of sin(2 φ 1 ) in Charmonium K 0 modes sin(2  1 )=0.667±0.023±0.012 A f =0.006±0.016±0.012 PRL108, (2012) Overpowering evidence for CP violation (matter-antimatter asymmetries). >>>> The phase of V td is in good agreement with Standard Model expectations J/  K S J/  K L 9 th June 2015

CP violation in B 0 D cp (*) h 0 10 D = D cp, CP eigenstates as K + K -, K s π 0, K s ω h 0 = π 0, ηω CP violation measurement performed using Indices i and j denotes the event reconstructed from BABAR and Belle data respectively. Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015 arXiv: Submitted to PRL

CP violation in B 0 D cp (*) h 0 11 Purity= 63% Purity= 55% sin(2 ϕ 1 ) = 0.66 ± 0.10 ± 0.06 The measurement is consistent with measurement from J/  K 0 Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

CPV in b sqq decays B 0 η ’K 0 12 JHEP 10 (2014) 165 Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

13 CPV in b sqq decays B 0 η ’K 0 JHEP 10 (2014) 165 Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

14 Process with third generation quarks and leptons New physics could change: Branching fraction Tau polarization Effect could be different for D and D * Experimental Challenge: 2 ( hadronic tau decay) or 3 (leptonic tau decay) undetected neutrinos Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

Signal Reconstruction 15 Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

Fit Projections High M 2 miss 16 Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

Result 17 Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

How About New Physics? 18 Consistent with 2HDM of type at tan β /m H+ ≈ 0.5 c 2 /GeV Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

Search for the dark photon and dark Higgs boson 19 Dark photon A’ and dark Higgs boson h’ hypothetical constituent in proposed Dark sector Models P. Fayet, Phys. Lett. B95, 285 (1980). Production and Decay: Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

Candidate Selection 20 Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015 and are the dark photon candidates with highest and lowest mass. Final Events summary after final selection

No significant Signal 21 90%CL upper limit on the product α D × ε 2 dark photon mass Dark Higgs mass Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015 α D : Dark photon coupling to dark Higgs boson: ε 2 = α ’ / α em

branching fraction 22 is given by From unitarity constrained B-decay constant from lattice calculation Expected to be highest for leptonic decay Eur. Phys. J. C 41, (2005) Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

Result 23 arXiv: arXiv: ) Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

24 Dr. Prafulla Kumar Behera, IIT Madras B  π 0 π 0 Proceeds via b u tree and ( EWP + QCD ) penguin B π 0 π 0 needed to remove “penguin pollution” Theory (QCD fact.) B≤ 1×10 -6 Nucl. Phys. B (2003) 9 th June 2015

25 Dr. Prafulla Kumar Behera, IIT Madras B  π 0 π 0 Results (preliminary) B ( B 0 π 0 π 0 ) = (0.90 ± 0.12 ± 0.10 ) × th June 2015

Conclusion 26 Measured angles and phase are consistent with SM. But % NP effects are consistent with data. Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015

Conclusion 27 Consistent with 2HDM of type at tan β /m H+ ≈ 0.5 c 2 /GeV No significant signal for dark photon and dark Higgs Measured branching ratio for B decays τν is consistent with SM Measured branching ratio for B decays to π 0 π 0 is consistent with SM Dr. Prafulla Kumar Behera, IIT Madras 9 th June 2015