The decay B-+/- -> K-S(0)pi(+/-), with a CP asymmetry expected to be close to zero in the standard model, is theoretically clean and sensitive to potential new physics. An analysis of the decays B-+/- -> K-S(0)pi(+/-) and B-+/- -> (KSK +/-)-K-0 is performed using proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb(-1). The CP asymmetries are determined to be A(CP)(B-+/- -> K-S(0)pi(+/-)) = -0.028 +/- 0.009 +/- 0.009 and A(CP)(B-+/- -> (KSK +/-)-K-0) = 0.118 +/- 0.062 +/- 0.031, and the branching fraction ratio is measured to be B(B-+/- -> (KSK +/-)-K-0)/B(B-+/- -> K-S(0)pi(+/-)) = 0.055 +/- 0.004 +/- 0.002, where the first uncertainties are statistical and the second are systematic. These results are the most precise measurements of these quantities to date. A search for the rare decay B-c(+/-) -> (KSK +/-)-K-0 is also performed. No significant signal is observed, and the upper limit on the product of the branching fraction ratio B(Bc(+/-) -> (KSK +/-)-K-0)/B(B-+/- -> K-S(0)pi(+/-)) and the fragmentation-fraction ratio f(c)/f(u) is set to be 0.015 (0.016) at the 90% (95%) confidence level.
Precision Measurement of CP Violation and Branching Fractions in B± → KS0h± (h = π, K) Decays and Search for the Rare Decay Bc± → KS0K±
De Angelis, C.;Dettori, F.;Manca, G.;Oldeman, R.;Provenzano, D.;Saitta, B.;
2026-01-01
Abstract
The decay B-+/- -> K-S(0)pi(+/-), with a CP asymmetry expected to be close to zero in the standard model, is theoretically clean and sensitive to potential new physics. An analysis of the decays B-+/- -> K-S(0)pi(+/-) and B-+/- -> (KSK +/-)-K-0 is performed using proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb(-1). The CP asymmetries are determined to be A(CP)(B-+/- -> K-S(0)pi(+/-)) = -0.028 +/- 0.009 +/- 0.009 and A(CP)(B-+/- -> (KSK +/-)-K-0) = 0.118 +/- 0.062 +/- 0.031, and the branching fraction ratio is measured to be B(B-+/- -> (KSK +/-)-K-0)/B(B-+/- -> K-S(0)pi(+/-)) = 0.055 +/- 0.004 +/- 0.002, where the first uncertainties are statistical and the second are systematic. These results are the most precise measurements of these quantities to date. A search for the rare decay B-c(+/-) -> (KSK +/-)-K-0 is also performed. No significant signal is observed, and the upper limit on the product of the branching fraction ratio B(Bc(+/-) -> (KSK +/-)-K-0)/B(B-+/- -> K-S(0)pi(+/-)) and the fragmentation-fraction ratio f(c)/f(u) is set to be 0.015 (0.016) at the 90% (95%) confidence level.| File | Dimensione | Formato | |
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