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Rare Semileptonic B-decays at LHCb. Marko Zupan. Overview. Brief look at formalism Observables of rare semileptonic B-decays and their significance Experimental status LHCb performance in the reconstruction of rare semileptonic B decays – Patrick Koppenburg Status of my analysis.
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Rare Semileptonic B-decays at LHCb Marko Zupan
Overview • Brief look at formalism • Observables of rare semileptonic B-decays and their significance • Experimental status • LHCb performance in the reconstruction of rare semileptonic B decays – Patrick Koppenburg • Status of my analysis
OPE Terms for Weak Decays • Current-Current Operators: Q1, Q2 , Qu1, Qu2 • QCD Penguin Operators: Q3, Q4, Q5, Q6 • Electroweak Penguin Operators: Q7, Q8, Q9, Q10 • Magnetic Penguin Operators: Q7g, Q8G • Semileptonic Operators: Q9V, Q10A, Qnn, Qmm
Relevant Penguin Operators for FCNC Decays Magnetic penguin operators Semileptonic penguin operators
b → sm m Decays • b→sll allow measurement of C7g, C9V, C10A • b→sg sensitive to |C7g|
Forward-Backward Charge Asymmetry m+ b s m-
Forward-Backward Charge Asymmetry s0 is stable against form factor modelling within SM
CP Violation CKM contribution O(10-3)
Beyond the Standard Model • Absolute values of Wilson coefficients modified • New complex phases for Wilson coefficients • New operator basis • CKM model may not hold
Experimental Results Branching Ratios at 90% CL
LHCb Performance: Dilepton Mass Distribution Inclusive channel dimuon mass distribution after one year of data taking
LHCb Performance: Hadron Mass Distribution Inclusive channel hadron mass distribution after one year of data taking
LHCb Performance: Forward-Backward Asymmetry B→mmK* B→mmK Forward-backward charge asymmetry after one year of data taking
LHCb Performance: Measuring |Vtd|/ |Vts| Relative uncertainty on after one year and five years of data taking |Vtd|/ |Vts|
Status of my analysis Where are all the Bs???
Status of my analysis (2) • Find muon vertex • cut on: • pt • impact parameter to primary vertex • dimuon mass • vertex 2 • Find and vertex combinations of kaons and pions Xs • K • Kp • Kpp • Kppp
Status of my analysis (3) • From dimuon and kaon-pion combinations reconstruct B-vertex • cut on: • impact parameter with respect to PV • impact parameter of Xs on dimuon • vertex 2 • charge of Xs • B mass
Status of my analysis (4) • Analysis done with Bender (v1r0) – • a Python wrapper of LoKi • Problems accessing MC truth information • Unclear binding to DaVinci algorithms and settings • Ease of use justifies “growing pains” • Any comment/advice welcome