BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2016). Observation of (B)over-bar -> D-(*()) pi(+)pi(-)l(-)(nu)over-bar Decays in e(+)e(-) Collisions at the Upsilon(4S) Resonance. Phys. Rev. Lett., 116(4), 041801–7pp.
Abstract: We report on measurements of the decays of (B) over bar mesons into the semileptonic final states (B) over bar -> D-(*())pi(+)pi(-)l(-)(nu) over bar, where D-(*()) represents a D or D* meson and l(-) is an electron or a muon. These measurements are based on 471 x 10(6) B (B) over bar pairs recorded with the BABAR detector at the SLAC asymmetric B factory PEP-II. We determine the branching fraction ratios R-pi+pi-(()*()) = B((B) over bar -> D-(*())pi(+)pi(-)l(-)(nu) over bar /B (B) over bar -> D-(*())l(-)(nu) over bar) using events in which the second B meson is fully reconstructed. We find R pi+pi- = 0.067 +/- 0.010 +/- 0.008 and R pi+pi-* = 0.019 +/- 0.005 +/- 0.004, where the first uncertainty is statistical and the second is systematic. Based on these results and assuming isospin invariance, we estimate that (B) over bar -> D-(*())pi pi l (nu) over bar decays, where pi denotes either a pi(+/-) and pi(0) meson, account for up to half the difference between the measured inclusive semileptonic branching fraction to charm hadrons and the corresponding sum of previously measured exclusive branching fractions.
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ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2016). Measurement of the ZZ Production Cross Section in pp Collisions at root s=13 TeV with the ATLAS Detector. Phys. Rev. Lett., 116(10), 101801–19pp.
Abstract: The ZZ production cross section in proton-proton collisions at 13 TeV center-of-mass energy is measured using 3.2 fb(-1) of data recorded with the ATLAS detector at the Large Hadron Collider. The considered Z boson candidates decay to an electron or muon pair of mass 66-116 GeV. The cross section is measured in a fiducial phase space reflecting the detector acceptance. It is also extrapolated to a total phase space for Z bosons in the same mass range and of all decay modes, giving 16.7(-2.0)(+2.2) (stat)(-0.7)(+0.9) (syst)(-0.7)(+1.0) (lumi) pb. The results agree with standard model predictions.
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T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Izmaylov, A., Sorel, M., & Stamoulis, P. (2016). Measurement of Muon Antineutrino Oscillations with an Accelerator-Produced Off-Axis Beam. Phys. Rev. Lett., 116(18), 181801–8pp.
Abstract: T2K reports its first measurements of the parameters governing the disappearance of (nu) over bar μin an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic (nu) over bar μbeam, produced with a peak energy of 0.6 GeVat J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the (nu) over bar μsurvival probability is expected to be minimal. Using a data set corresponding to 4.01 x 10(20) protons on target, 34 fully contained mu-like events were observed. The best-fit oscillation parameters are sin(2) ((theta) over bar (23)) = 0.45 and vertical bar Delta(m) over bar (2)(32)vertical bar = 2.51 x 10(-3) eV(2) with 68% confidence intervals of 0.38-0.64 and 2.26-2.80 x 10(-3) eV(2), respectively. These results are in agreement with existing antineutrino parameter measurements and also with the nu(mu) disappearance parameters measured by T2K.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Observation of B-s(0) -> (D)over-bar(0)K(S)(0) and Evidence for B-s(0) -> (D)over-bar*K-0(S)0 Decays. Phys. Rev. Lett., 116(16), 161802–9pp.
Abstract: The first observation of the B-s(0) -> (D) over bar K-0(S)0 decay mode and evidence for the B-s(0) -> (D) over bar*K-0(S)0 decay mode are reported. The data sample corresponds to an integrated luminosity of 3.0 fb-1 collected in pp collisions by LHCb at center-of-mass energies of 7 and 8 TeV. The branching fractions are measured to be B(B-s(0) -> (D) over bar (0)(K) over bar (0)) = [4.3 +/- 0.5(stat) +/- 0.3 (syst) +/- 0.3(frag) +/- 0.6(norm)] x 10(-4), B(B-s(0) -> (D) over bar*(0)(K) over bar (0)) = [2.8 +/- 1.0(stat) +/- 0.3 (syst) +/- 0.2(frag) +/- 0.4(norm)] x 10(-4), where the uncertainties are due to contributions coming from statistical precision, systematic effects, and the precision of two external inputs, the ratio f(s)/f(d) and the branching fraction of B-0 (D) over bar K-0(S)0, which is used as a calibration channel.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Measurement of the Difference of Time-Integrated CP Asymmetries in D-0 -> K-K+ and D-0 -> pi(-)pi(+) Decays. Phys. Rev. Lett., 116(19), 191601–10pp.
Abstract: A search for CP violation in D-0 -> K-K+ and D-0 -> pi(-)pi(+) decays is performed using pp collision data, corresponding to an integrated luminosity of 3 fb(-1), collected using the LHCb detector at center-of-mass energies of 7 and 8 TeV. The flavor of the charm meson is inferred from the charge of the pion in D*(+) -> D-0 pi(+) and D*(-) -> (D) over bar (0)pi(-) decays. The difference between the CP asymmetries in D-0 -> K-K+ and D-0 -> pi(-)pi(+) decays, Delta A(CP) A(CP)(K-K+) – A(CP)(pi(-)pi(+)), is measured to be [-0.10 +/- 0.08(stat) +/- 0.03(syst)]%. This is the most precise measurement of a time-integrated CP asymmetry in the charm sector from a single experiment.
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