|
|
LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2023). Search for D*(2007)0 → μ+ μ- in B- → π- μ+ μ- decays. Eur. Phys. J. C, 83(7), 666–14pp.
Abstract: The very rare D*(2007)(0) -> mu(+) mu(-) decay is searched for by analysing B- -> pi (-) mu(+) mu(-) decays. The analysis uses a sample of beautymesons produced in protonproton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb(-1). The signal signature corresponds to simultaneous peaks in the mu(+) mu(-) and pi(-) mu(+) mu(-) invariant masses. No evidence for an excess of events over background is observed and an upper limit is set on the branching fraction of the decay at B(D-*(2007)(0) -> mu(+) mu(-)) < 2.6 x 10(-8) at 90% confidence level. This is the first limit on the branching fraction of D*(2007)(0) -> mu(+) mu(-) decays and the most stringent limit on D* (2007)(0) decays to leptonic final states. The analysis is the first search for a rare charm-meson decay exploiting production via beauty decays.
|
|
|
|
LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2018). Amplitude Analysis of the Decay (B)over-bar(0 )-> K-S(0)pi(+)pi(- )and First Observation of the CP Asymmetry in (B)over-bar(0 )-> K* (892)(-)pi(+). Phys. Rev. Lett., 120(26), 261801–10pp.
Abstract: The time-integrated untagged Dalitz plot of the three-body hadronic charmless decay (B) over bar (0 )-> K-S(0)pi(+)pi(- ) is studied using a pp collision data sample recorded with the LHCb detector, corresponding to an integrated luminosity of 3.0 fb(-1). The decay amplitude is described with an isobar model. Relative contributions of the isobar amplitudes to the (B) over bar (0 )-> K-S(0)pi(+)pi(- ) decay branching fraction and CP asymmetries of the flavor-specific amplitudes are measured. The CP asymmetry between the conjugate (B) over bar (0 )-> K* (892)(-)pi(+) and (B) over bar (0 )-> K* (892)(-)pi(+) decay rates is determined to be -0.308 +/- 0.062.
|
|
|
|
LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2023). Measurement of the Time-Integrated CP Asymmetry in D0 → K- K+ Decays. Phys. Rev. Lett., 131(9), 091802–13pp.
Abstract: The time-integrated CP asymmetry in the Cabibbo suppressed decay PKK is measured using proton proton collision data, corresponding to an integrated luminosity of 5.7 th collected at a center of mass energy of 13 TeV with the LHCb detector. The D mesons are required to originate from promptly produced DD's decays, and the charge of the companion pion is used to determine the flavor of the charm meson at production. The time integrated CP asymmetry is measured to be Acr(KK) 6,815.41.6 x 10 where the first uncertainty is statistical and the second systematic. The direct CP asymmetries in D-K-K and D -> decays, and are derived by combining Ace(KK) with the time integrated CP asymmetry differ ence, AAcr-Acr(KK)-A(x), and other inputs, giving a (7.715.7) x 10, (23.2 16.1) x 10, with a correlation coefficient corresponding to p=0.88. The compatibility of these results with CP symmetry is 1.4 and 3.8 standard deviations for DKK and D degrees-xx decays, respectively. This is the first evidence for direct CP violation in a specific Do decay.
|
|
|
|
LHCb Collaboration(Aaij, R. et al), Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2021). Observation of CP violation in two-body B-(s)(0)-meson decays to charged pions and kaons. J. High Energy Phys., 03(3), 075–43pp.
Abstract: The time-dependent CP asymmetries of B-0 -> pi(+)pi(-) and B-s(0) -> K+K- decays are measured using a data sample of pp collisions corresponding to an integrated luminosity of 1.9 fb(-1), collected with the LHCb detector at a centre-of-mass energy of 13TeV. The results are C-pi pi = 0.311 +/- 0.045 +/- 0.015; S-pi pi = 0.706 +/- 0.042 +/- 0.013; C-KK = 0.164 +/- 0.034 +/- 0.014; S-KK = 0.123 +/- 0.034 +/- 0.015; A(KK)(Delta Gamma) = -0.83 +/- 0.05 +/- 0.09; where the first uncertainties are statistical and the second systematic. The same data sample is used to measure the time-integrated CP asymmetries of B-0 -> K + pi(-) and B-s(0) -> K-pi(+) decays and the results are AB(CP)(B0) = -0.0824 +/- 0.0033 +/- 0.0033; A(CP)(Bs0) = 0.236 +/- 0.013 +/- 0.011. All results are consistent with earlier measurements. A combination of LHCb measurements provides the first observation of time-dependent CP violation in B-s(0) decays.
|
|
|
|
LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2018). Measurement of CP asymmetries in two-body B-(s)(0)-meson decays to charged pions and kaons. Phys. Rev. D, 98(3), 032004–23pp.
Abstract: The time-dependent CP asymmetries in B-0 -> pi(+)pi(-) and B-(s)(0) -> K+K- decays are measured using a data sample of p p collisions corresponding to an integrated luminosity of 3.0 fb(-1), collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The same data sample is used to measure the time-integrated CP asymmetries in B-0 -> K+pi(-) and B-(s)(0) -> pi K-+(-) decays. The results are C pi+pi- = -0.34 +/- 0.06 +/- 0.01, S pi+pi- = -0.63 +/- 0.05 +/- 0.01, CK+K- = 0.20 +/- 0.06 +/- 0.02, SK+K- = 0.18 +/- 0.06 +/- 0.02, A(K+K-)(Delta Gamma) = -0.79 +/- 0.07 +/- 0.10, A(CP)(B0) = -0.084 +/- 0.004 +/- 0.003, and A(CP)(B0s) = 0.213 +/- 0.015 +/- 0.007, where the first uncertainties are statistical and the second systematic. Evidence for CP violation is found in the B-s(0) -> K+K- decay for the first time.
|
|
