Engineering topics
Baranov, A.
Publications and source records attributed to Baranov, A..
Search for the Rare Decays B s 0 → e + e − and B 0 → e + e −
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Test of lepton universality with $ {\Lambda}_b^0\to {pK}^{-}{\mathrm{\ell}}^{+}{\mathrm{\ell}}^{-}$ decays
The ratio of branching fractions of the decays \( {\Lambda}_b^0 \) → pK - e + e - and \( {\Lambda}_b^0 \) → pK - μ + μ - , \( {R}_{pK}^{-1} \) , is measured for the first time using proton-proton collision data corresponding to an integrated luminosity of 4 . 7 fb - 1 recorded with the LHCb experiment at center-of-mass energies of 7, 8 and 13 TeV. In the dilepton mass-squared range 0 . 1 < q 2 < 6 . 0 GeV 2 /c 4 and the pK - mass range m ( pK - ) < 2600 MeV /c 2 , the ratio of branching fractions is measured to be \( {R}_{pK}^{-1}={1.17}_{-0.16}^{+0.18}\pm 0.07 \) , where the first uncertainty is statistical and the second systematic. This is the first test of lepton universality with b baryons and the first observation of the decay \( {\Lambda}_b^0 \) → pK - e + e - .