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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2016). Search for a muonic dark force at BABAR. Phys. Rev. D, 94(1), 011102–7pp.
Abstract: Many models of physics beyond the standard model predict the existence of new Abelian forces with new gauge bosons mediating interactions between “dark sectors” and the standard model. We report a search for a dark boson Z' coupling only to the second and third generations of leptons in the reaction e(+)e(-) -> mu(+)mu(-) Z', Z' -> mu(+)mu(-) using 514 fb(-1) of data collected by the BABAR experiment. No significant signal is observed for Z' masses in the range 0.212-10 GeV. Limits on the coupling parameter g' as low as 7 x 10(-4) are derived, leading to improvements in the bounds compared to those previously derived from neutrino experiments.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2016). Measurement of the B-0 -> D*(-)pi(+)pi(-)pi(+) branching fraction. Phys. Rev. D, 94(9), 091101–7pp.
Abstract: Using a sample of (470.9 +/- 2.8) x 10(6) B (B) over bar pairs, we measure the decay branching fraction B(B-0 -> D*(-)pi(+)pi(-)pi(-)) = (7.26 +/- 0.11 +/- 0.31) x 10(-3), where the first uncertainty is statistical and the second is systematic. Our measurement will be helpful in studies of lepton universality by measuring B(B-0 -> D*(-)tau(+)nu(tau)) using tau(+) -> pi(+)pi(-)pi(+)(nu) over bar (tau) decays, normalized to B(B-0 -> D*(-)pi(+)pi(-)pi(-)).
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2017). Measurement of the inclusive electron spectrum from B meson decays and determination of vertical bar V-ub vertical bar. Phys. Rev. D, 95(7), 072001–23pp.
Abstract: Based on the full BABAR data sample of 466.5 million B (B) over bar pairs, we present measurements of the electron spectrum from semileptonic B meson decays. We fit the inclusive electron spectrum to distinguish Cabibbo-Kobayashi-Maskawa (CKM) suppressed B -> X(u)ev decays from the CKM-favored B -> X(u)ev decays, and from various other backgrounds, and determine the total semileptonic branching fraction B(B -> X(u)ev) = (10.34 +/- 0.04(stat) +/- 0.26(syst))%, averaged over B-+/- and B-0 mesons. We determine the spectrum and branching fraction for charmless B -> X(u)ev decays and extract the CKM element vertical bar V-ub vertical bar, by relying on four different QCD calculations based on the heavy quark expansion. While experimentally, the electron momentum region above 2.1 GeV/c is favored, because the background is relatively low, the uncertainties for the theoretical predictions are largest in the region near the kinematic endpoint. Detailed studies to assess the impact of these four predictions on the measurements of the electron spectrum, the branching fraction, and the extraction of the CKM matrix element vertical bar V-ub vertical bar are presented, with the lower limit on the electron momentum varied from 0.8 GeV/c to the kinematic endpoint. We determine V-ub vertical bar using each of these different calculations and find, vertical bar V-ub vertical bar = (3.794 +/- 0.107(exp) (+0.292)(-0.219) (SF) (+0.078)(-0.068)theory) x 10(-3) (De Fazio and Neubert), (4.563 +/- 0.126(exp) (+0.230)(+0.162)(-0.208)(-0.163)theory) x 10(-3) (Bosch, Lange, Neubert, and Paz), (3.959 +/- 0.104(exp -0.154)(SF-0.079)(+0.164)(+0.042) theory )x 10(-3) (Gambino, Giordano, Ossola, and Uraltsev), (3.848 +/- 0.108(exp -0.070)(theory)(+0.084)) x 10(-3) (dressed gluon exponentiation), where the stated uncertainties refer to the experimental uncertainties of the partial branching fraction measurement, the shape function parameters, and the theoretical calculations.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2017). Cross sections for the reactions e(+)e(-) -> (KSKL0)-K-0 pi(0), (KSKL0)-K-0 eta, and (KSKL0)-K-0 pi(0)pi(0) from events with initial-state radiation. Phys. Rev. D, 95(5), 052001–16pp.
Abstract: We study the processes e(+)e(-) -> (KSKL0)-K-0 pi(0)gamma, (KSKL0)-K-0 eta gamma, and (KSKL0)-K-0 pi(0)pi(0)gamma, where the photon is radiated from the initial state, providing cross section measurements for the hadronic final states over a continuum of center-of-mass energies. The results are based on 469 fb(-1) of data collected at or near the psi(4S) resonance with the BABAR detector at SLAC. We present the first measurements of the e(+)e(-) -> (KSKL0)-K-0 pi(0), (KSKL0)-K-0 eta, and (KSKL0)-K-0 pi(0)pi(0) cross sections up to a center-of-mass energy of 4 GeV and study their intermediate resonance structures. We observe J/psi decays to all of these final states for the first time, present measurements of their J/psi branching fractions, and search for psi(2S)decays.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2017). Dalitz plot analyses of J / psi -> pi(+) pi(-) pi(0), J / psi -> K+ K- pi(0), and J / psi -> (KsK +/-)-K-0 pi(-/+) produced via e (+) e (-) annihilation with initial-state radiation. Phys. Rev. D, 95(7), 072007–19pp.
Abstract: We study the processes e(+)e(-) -> gamma ISRJ (/) (psi), where J / psi pi(+)pi(-) pi(0), J / psi -> K+K-pi(0), and J / psi -> (KSK +/-)-K-0 pi(-/+) using a data sample of 519 fb(-1) recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e(+) e(-) collider at center-of-mass energies at and near the Y(nS) (n = 2, 3, 4) resonances. We measure the ratio of branching fractions R-1 = B(J / psi -> K+K-pi(0))/B(J / psi ->pi(+)pi(-)pi(0)) and R-2 = B(J / psi -> K-S(0) K-+/- p(-/+))/B(J / psi ->pi(+)pi(-)pi(0)). We perform Dalitz plot analyses of the three J / psi decay modes and measure fractions for resonances contributing to the decays. We also analyze the J /psi -> pi(+)pi(-)pi(0) decay using the Veneziano model. We observe structures compatible with the presence of rho(1450) in all three J / psi decay modes and measure the relative branching fraction: R(rho(1450)) = B(rho(1450)-> K+K-)/B(rho(1450)->pi(+)pi(-)) = 0.307 +/- 0.084(stat) +/- 0.082(sys).
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