0000000000559833
AUTHOR
P. Villanueva-perez
Measurement of theD*(2010)+natural linewidth and theD*(2010)+−D0mass difference
We measure the mass difference, Δm_0, between the D^*(2010)^+ and the D^0 and the natural linewidth, Γ, of the transition D^*(2010)^+ → D^0π^+. The data were recorded with the BABAR detector at center-of-mass energies at and near the Υ(4S) resonance, and correspond to an integrated luminosity of approximately 477 fb^(-1). The D^0 is reconstructed in the decay modes D^0 → K^-π^+ and D^0 → K^-π^+π^-π^+. For the decay mode D^0 → K^-π^+ we obtain Γ=(83.4±1.7±1.5) keV and Δm_0=(145425.6±0.6±1.8) keV, where the quoted errors are statistical and systematic, respectively. For the D^0 → K^-π^+π^-π^+ mode we obtain Γ=(83.2±1.5±2.6) keV and Δm_0 = (145426.6±0.5±2.0) keV. The combined measurements…
Search for a low-mass scalar Higgs boson decaying to a tau pair in single-photon decays of Y(1S)
We search for a low-mass scalar CP-odd Higgs boson, A(0), produced in the radiative decay of the upsilon resonance and decaying into a tau(+)tau(-) pair: Y(1S) -> gamma A(0). The production of Y(1S) mesons is tagged by Y(2S) -> pi(+)pi(-) Y(1S) transitions, using a sample of (98.3 +/- 0.9) x 10(6) Y(2S) mesons collected by the BABAR detector. We find no evidence for a Higgs boson in the mass range 3: 5 <= m(A)0 <= 9: 2 GeV, and combine these results with our previous search for the tau decays of the light Higgs in radiative Y(3S) decays, setting limits on the coupling of A(0) to the b (b) over bar quarks in the range 0.09-1.9. Our measurements improve the constraints on the parameters of th…
Time Reversal Violation from the entangled B0-antiB0 system
We discuss the concepts and methodology to implement an experiment probing directly Time Reversal (T) non-invariance, without any experimental connection to CP violation, by the exchange of "in" and "out" states. The idea relies on the B0-antiB0 entanglement and decay time information available at B factories. The flavor or CP tag of the state of the still living neutral meson by the first decay of its orthogonal partner overcomes the problem of irreversibility for unstable systems, which prevents direct tests of T with incoherent particle states. T violation in the time evolution between the two decays means experimentally a difference between the intensities for the time-ordered (l^+ X, J…
Observation of Time-Reversal Violation in the B0 Meson System
Although CP violation in the B meson system has been well established by the B factories, there has been no direct observation of time reversal violation. The decays of entangled neutral B mesons into definite flavor states ($B^0$ or $\bar{B}^0$), and $J/\psi K_S^0$ or $c\bar{c} K_S^0$ final states (referred to as $B_+$ or $B_-$), allow comparisons between the probabilities of four pairs of T-conjugated transitions, for example, $\bar{B}^0 \rightarrow B_-$ and $B_- \rightarrow \bar{B}^0$, as a function of the time difference between the two B decays. Using 468 million $B\bar{B}$ pairs produced in $\Upsilon(4S)$ decays collected by the BABAR detector at SLAC, we measure T-violating parameter…
Search forCPViolation inB0-B¯0Mixing Using Partial Reconstruction ofB0→D*−Xℓ+νℓand a Kaon Tag
We present results of a search for CP violation in B^0- B^0 mixing with the BABAR detector. We select a sample of B^0→D^(*-)Xl^+ν decays with a partial reconstruction method and use kaon tagging to assess the flavor of the other B meson in the event. We determine the CP violating asymmetry A_(CP)≡[N(B^0B^0)-N(B^0B^0)]/[N(B^0B^0)+N(B^0B^0)]=(0.06±0.17_(-0.32)^(+0.38))%, corresponding to Δ_(CP) = 1- |q/p|=(0.29±0.84_(-1.61)^(+1.88))×10^(-3).
Measurement of the mass of the D^{0} meson
We report a measurement of the D-0 meson mass using the decay chain D* (2010) + -> D-0 pi(+) with D-0 -> K-K-K+pi(+). The data were recorded with the BABAR detector at center-of-mass energies at and near the Upsilon(4S) resonance, and correspond to an integrated luminosity of approximately 477 fb(-1). We obtain m(D-0) (1864: 841 +/- 0: 048 +/- 0: 063) MeV, where the quoted errors are statistical and systematic, respectively. The uncertainty of this measurement is half that of the best previous measurement.
Measurement of thee+e−→pp¯cross section in the energy range from 3.0 to 6.5 GeV
The e^+e^−→pp cross section and the proton magnetic form factor have been measured in the center-of-mass energy range from 3.0 to 6.5 GeV using the initial-state radiation technique with an undetected photon. This is the first measurement of the form factor at energies higher than 4.5 GeV. The analysis is based on 469 fb^(−1) of integrated luminosity collected with the BABAR detector at the PEP-II collider at e+e− center-of-mass energies near 10.6 GeV. The branching fractions for the decays J/ψ→pp and ψ(2S)→pp have also been measured.
Measurement of an excess ofB¯→D(*)τ−ν¯τdecays and implications for charged Higgs bosons
The concept for this analysis is to a large degree based on earlier BABAR work and we acknowledge the guidance provided by M. Mazur. The authors consulted with theorists A. Datta, S. Westhoff, S. Fajfer, J. Kamenik, and I. Nisandzic on the calculations of the charged Higgs contributions to the decay rates. We are grateful for the extraordinary contributions of our PEP-II colleagues in achieving the excellent luminosity and machine conditions that have made this work possible. The success of this project also relied critically on the expertise and dedication of the computing organizations that support BABAR. The collaborating institutions wish to thank SLAC for its support and the kind hospi…
Search for the rare decaysB→πℓ+ℓ−andB0→ηℓ+ℓ−
We present the results of a search for the rare flavor-changing neutral-current decays B → πl^+ l^- (π = π^±, π^0 and l = e, μ) and B^0 → ηl^+ l^- using a sample of e^+ e^- → Υ(4S) → BB decays corresponding to 428 fb^(-1) of integrated luminosity collected by the BABAR detector. No significant signal is observed, and we set an upper limit on the isospin and lepton-flavor averaged branching fraction of B(B → πl^+ l^-)<5.9 × 10^(-8) and a lepton-flavor averaged upper limit of B(B0 → ηl^+ l^-) < 6.4 × 10^(-8), both at the 90% confidence level. We also report 90% confidence level branching fraction upper limits for the individual modes B^+ → π^+ e^+ e^-, B^0 → π^0 e^+ e^-, B^+ → π^+ μ^+ μ^-, B…
Production of charged pions, kaons, and protons ine+e−annihilations into hadrons ats=10.54 GeV
Inclusive production cross sections of π^±, K^± and p/p per hadronic e^+e^- annihilation event are measured at a center-of-mass energy of 10.54 GeV, using a relatively small sample of very high quality data from the BABAR experiment at the PEP-II B-factory at the SLAC National Accelerator Laboratory. The drift chamber and Cherenkov detector provide clean samples of identified π^±, K^±, and p/p over a wide range of momenta. Since the center-of-mass energy is below the threshold to produce a BB pair, with B a bottom-quark meson, these data represent a pure e^+e^-→qq sample with four quark flavors, and are used to test QCD predictions and hadronization models. Combined with measurements at oth…