Observation of the Annihilation Decay Mode <i>B</i><SUP>0</SUP> → <i>K</i><SUP>+</SUP><i>K</i><SUP>-</SUP>

A search for the B^{0}→K^{+}K^{-} decay is performed using pp-collision data collected by LHCb. The data set corresponds to integrated luminosities of 1.0 and 2.0  fb^{-1} at center-of-mass energies of 7 and 8 TeV, respectively. This decay is observed for the first time, with a significance of more than 5 standard deviations. The analysis also results in an improved measurement of the branching fraction for the B_{s}^{0}→π^{+}π^{-} decay. The measured branching fractions are B(B^{0}→K^{+}K^{-})=(7.80±1.27±0.81±0.21)×10^{-8} and B(B_{s}^{0}→π^{+}π^{-})=(6.91±0.54±0.63±0.19±0.40)×10^{-7}. The first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the B^{0}→K^{+}π^{-} branching fraction used as a normalization. For the B_{s}^{0} mode, the fourth accounts for the uncertainty on the ratio of the probabilities for b quarks to hadronize into B_{s}^{0} and B^{0} mesons

Measurement of the shape of the Λ[superscript 0][subscript b] → Λ[superscript +][subscript c]μ[superscript −][bar over ν][subscript μ] differential decay rate

A measurement of the shape of the differential decay rate and the associated Isgur-Wise function for the decay Λ[superscript 0][subscript b] → Λ[superscript +][subscript c]μ[superscript −][bar over ν][subscript μ] reported, using data corresponding to 3  fb[superscript -1] collected with the LHCb detector in proton-proton collisions. The Λ[superscript +][subscript c]μ[superscript −][bar over ν][subscript μ](+anything) final states are reconstructed through the detection of a muon and a Λ[superscript +][subscript c] baryon decaying into pK[superscript -]π[superscript +], and the decays Λ[superscript 0][subscript b]→Λ[superscript +][subscript c]π[superscript +]π[superscript -]μ[superscript -][bar vover v][subscript μ] are used to determine contributions from Λ[superscript 0][subscript b] → Λ[superscript +][subscript c]μ[superscript −][bar over ν][subscript μ] decays. The measured dependence of the differential decay rate upon the squared four-momentum transfer between the heavy baryons, q[superscript 2], is compared with expectations from heavy-quark effective theory and from unquenched lattice QCD predictions.National Science Foundation (U.S.

Effective lifetime measurements in the Bs0→K+K-, B0→K+π-and B0s→π+K-decays

Measurements of the effective lifetimes in the Bs0→K+K-,B0→K +π- and Bs0→π+K- decays are presented using 1.0 fb -1 of pp collision data collected at a centre-of-mass energy of 7 TeV by the LHCb experiment. The analysis uses a data-driven approach to correct for the decay time acceptance. The measured effective lifetimes areτBs0→K+K-=1.407±0.016(stat)±0.007(syst) ps,τB0→K+π-=1.524±0.011(stat)±0.004(syst) ps,τBs0→π+K-=1.60±0.06(stat)±0.01(syst) ps. This is the most precise determination to date of the effective lifetime in the Bs0→K+K- decay and provides constraints on contributions from physics beyond the Standard Model to the Bs0 mixing phase and the width difference δΓs. © 2014 The Authors

Observation of the Annihilation Decay Mode B-0 -> K+K-

A search for the B-0 -> K+K- decay is performed using pp-collision data collected by LHCb. The data set corresponds to integrated luminosities of 1.0, 2.0 fb(-1) at center-of-mass energies of 7, 8 TeV, respectively. This decay is observed for the first time with a significance of more than 5 standard deviations. The analysis also results in an improved measurement of the branching fraction for the B-s(0) -> pi(+)pi(-) decay. The measured branching fractions are B(B-0 -> K+K-) = (7.80 +/- 1.27 +/- 0.81 +/- 0.21) x 10(-8), B(B-s(0) -> pi(+)p(-)) = (6.91 +/- 0.54 +/- 0.63 +/- 0.19 +/- 0.40) x 10(-7). The first uncertainty is statistical the second is systematic the third is due to the uncertainty on the B-0 -> K+pi(-) branching fraction used as a normalization. For the B-s(0) mode the fourth accounts for the uncertainty on the ratio of the probabilities for b quarks to hadronize into B-s(0), B-0 mesons

Observation of the Annihilation Decay Mode B-0 -> K+K-

A search for the B-0 -> K+K- decay is performed using pp-collision data collected by LHCb. The data set corresponds to integrated luminosities of 1.0, 2.0 fb(-1) at center-of-mass energies of 7, 8 TeV, respectively. This decay is observed for the first time with a significance of more than 5 standard deviations. The analysis also results in an improved measurement of the branching fraction for the B-s(0) -> pi(+)pi(-) decay. The measured branching fractions are B(B-0 -> K+K-) = (7.80 +/- 1.27 +/- 0.81 +/- 0.21) x 10(-8), B(B-s(0) -> pi(+)p(-)) = (6.91 +/- 0.54 +/- 0.63 +/- 0.19 +/- 0.40) x 10(-7). The first uncertainty is statistical the second is systematic the third is due to the uncertainty on the B-0 -> K+pi(-) branching fraction used as a normalization. For the B-s(0) mode the fourth accounts for the uncertainty on the ratio of the probabilities for b quarks to hadronize into B-s(0), B-0 mesons

Measurement of the shape of the Lambda(0)(b) ->+ Lambda(+)(c) mu(-)(nu)over-bar mu differential decay rate

A measurement of the shape of the differential decay rate and the associated Isgur-Wise function for the decay Λ 0 b → Λ + c μ − ¯ ν μ is reported, using data corresponding to 3     fb − 1 collected with the LHCb detector in proton-proton collisions. The Λ + c μ − ¯ ν μ ( + anything ) final states are reconstructed through the detection of a muon and a Λ + c baryon decaying into p K − π + , and the decays Λ 0 b → Λ + c π + π − μ − ¯ ν μ are used to determine contributions from Λ 0 b → Λ * + c μ − ¯ ν μ decays. The measured dependence of the differential decay rate upon the squared four-momentum transfer between the heavy baryons, q 2 , is compared with expectations from heavy-quark effective theory and from unquenched lattice QCD predictions

Measurement of the shape of the Lambda(0)(b) ->+ Lambda(+)(c) mu(-)(nu)over-bar mu differential decay rate

A measurement of the shape of the differential decay rate and the associated Isgur-Wise function for the decay Λ0 b → Λ+c μ- νμ is reported, using data corresponding to 3 fb-1collected with the LHCb detector in proton-proton collisions. The Λ+c μ- νμ anything final states are reconstructed through the detection of a muon and a Λ+c baryon decaying into pK-π+, and the decays Λ0 b → Λ+c π+π-μ- νμ are used to determine contributions from Λ0 b → Λ0c μ- νμ decays. The measured dependence of the differential decay rate upon the squared four-momentum transfer between the heavy baryons, q2, is compared with expectations from heavy-quark effective theory and from unquenched lattice QCD predictions