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 violation in B-0 -> D-/+pi(+/-) decays. J. High Energy Phys., 06(6), 084–23pp.
Abstract: A measurement of the CP asymmetries S-f and S-(f) over bar in B-0 -> D--/+pi(+/-) decays is reported. The decays are reconstructed in a dataset collected with the LHCb experiment in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV and corresponding to an integrated luminosity of 3.0 fb(-1). The CP asymmetries are measured to be S-f = 0.058 +/- 0.020(stat) +/- 0.011(syst) and S-(f) over bar = 0.038 +/- 0.020(stat) +/- 0.007(syst). These results are in agreement with, and more precise than, previous determinations. They are used to constrain angles of the unitarity triangle, vertical bar sin (2 beta + gamma)vertical bar and gamma, to intervals that are consistent with the current world-average values.
|
LHCb Collaboration(Aaij, R. et al), Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2021). Measurement of CP asymmetry in D-0 -> KS0 KS0 decays. Phys. Rev. D, 104(3), L031102–11pp.
Abstract: A measurement of the CP asymmetry in D-0 -> (KSKS0)-K-0 decays is reported, based on a data sample of proton-proton collisions collected by the LHCb experiment from 2015 to 2018, corresponding to an integrated luminosity of 6 fb(-1). The flavor of the D-0 candidate is determined using the charge of the D-*+/- meson, from which the decay is required to originate. The D-0 -> K+K- decay is used as a calibration channel. The time-integrated CP asymmetry for the D-0 -> (KSKS0)-K-0 mode is measured to be A(CP)(D-0 -> (KSKS0)-K-0) = (-3.1 +/- 1.2 +/- 0.4 +/- 0.2), where the first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty on the CP asymmetry of the calibration channel. This is the most precise determination of this quantity to date.
|
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 CKM angle γ using the B± → D*h± channels. J. High Energy Phys., 12(12), 013–32pp.
Abstract: A measurement of the CP-violating observables from B -> (DK +/-)-K-* and B-+/- -> D-*pi(+/-) decays is presented, where D-*(D) is an admixture of D-*0 and D-0 (D-0 and (0)) states and is reconstructed through the decay chains D-*-> D pi(0)/gamma and D -> KS0 pi+pi-/KS0K+K-. The measurement is performed by analysing the signal yield variation across the D decay phase space and is independent of any amplitude model. The data sample used was collected by the LHCb experiment in proton-proton collisions and corresponds to a total integrated luminosity of 9 fb(-1) at centre-of-mass energies of 7, 8 and 13 TeV. The CKM angle gamma is determined to be (69(-14)(+13))degrees using the measured CP-violating observables. The hadronic parameters r(B)(D)*(K +/-),r(B)(D)*(pi +/-),delta(D)(B)*(K +/-),delta(D)(B)*(pi +/-), which are the ratios and strong phase differences between favoured and suppressed B-+/- decays, are also reported.
|
ATLAS Collaboration(Aad, G. et al), Amos, K. R., Aparisi Pozo, J. A., Bailey, A. J., Cabrera Urban, S., Cardillo, F., et al. (2022). Measurement of the energy asymmetry in t(t)over-barj production at 13 TeV with the ATLAS experiment and interpretation in the SMEFT framework. Eur. Phys. J. C, 82(4), 374–36pp.
Abstract: A measurement of the energy asymmetry in jet-associated top-quark pair production is presented using 139 fb(-1) of data collected by the ATLAS detector at the Large Hadron Collider during pp collisions at root s = 13 TeV. The observable measures the different probability of top and antitop quarks to have the higher energy as a function of the jet scattering angle with respect to the beam axis. The energy asymmetry is measured in the semileptonic t (t) over bar decay channel, and the hadronically decaying top quark must have transverse momentum above 350 GeV. The results are corrected for detector effects to particle level in three bins of the scattering angle of the associated jet. The measurement agrees with the SM prediction at next-to-leading-order accuracy in quantum chromodynamics in all three bins. In the bin with the largest expected asymmetry, where the jet is emitted perpendicular to the beam, the energy asymmetry is measured to be -0.043 +/- 0.020, in agreement with the SM prediction of -0.037 +/- 0.003. Interpreting this result in the framework of the Standard Model effective field theory (SMEFT), it is shown that the energy asymmetry is sensitive to the top-quark chirality in four-quark operators and is therefore a valuable new observable in global SMEFT fits.
|
NA48/2 Collaboration(Batley, J. R. et al), & Fiorini, L. (2018). Measurement of the form factors of charged kaon semileptonic decays. J. High Energy Phys., 10(10), 150–23pp.
Abstract: A measurement of the form factors of charged kaon semileptonic decays is presented, based on 4.4 x 10(6)K(+/-) (0)e(e)(+/-) (Ke3 +/-) and 2.3 x 10(6)K(+/-) (0)+/- (K3 +/-) decays collected in 2004 by the NA48/2 experiment. The results are obtained with improved precision as compared to earlier measurements. The combination of measurements in the Ke3 +/- and K3 +/- modes is also presented.
|
