Search for a light Higgs resonance in radiative decays of the Y(1S) with a charm tag

A search is presented for the decay Y(1S) -> gamma A0, A0 -> cc-bar, where A0 is a candidate for the CP-odd Higgs boson of the next-to-minimal supersymmetric standard model. The search is based on data collected with the BABAR detector at the Y(2S) resonance. A sample of Y(1S) mesons is selected via the decay Y(2S) -> pi+pi-Y(1S). The A0 -> cc-bar decay is identified through the reconstruction of hadronic D0, D+, and D*(2010)+ meson decays. No significant signal is observed. The measured 90% confidence-level upper limits on the product branching fraction B(Y(1S) -> gamma A0) x B(A0 -> cc-bar) range from 7.4 x 10^-5 to 2.4 x 10^-3 for A0 masses from 4.00 to 8.95 GeV/c^2 and 9.10 to 9.25 GeV/c^2, where the region between 8.95 and 9.10 GeV/c^2 is excluded because of background from Y(2S) -> gamma chi_bJ(1P), chi_bJ(1P) -> gamma Y(1S) decays.Comment: 8 pages, 8 postscript figures, submitted to PRD-R

DIRC, the Internally Reflecting Ring Imaging Cherenkov Detector for BABAR

The DIRC is a new type of Cherenkov imaging device that will be used for the first time in the BABAR detector at the asymmetric B-factory, PEP-II. It is based on total internal reflection and uses long, rectangular bars made from synthetic fused silica as Cherenkov radiator and light guide. The principles of the DIRC ring imaging Cherenkov technique are explained and results from the prototype program are presented. Its choice for the BABAR detector particle identification system is motivated, followed by a discussion of the quartz radiator properties and the detector design.Comment: Invited talk given at the 1997 IEEE Nuclear Science Symposium and Medical Imaging Conference, Albuquerque, Nov 9-15 1997, submitted to IEEE Trans. Nucl. Sc

Search for Lepton-Flavor Violation in the Decay tau -> lhh

A search for the lepton-flavor-violating decay of the tau into one charged lepton and two charged hadrons has been performed using $221.4 \mathrm{fb}^{-1}$ of data collected at an $e^+e^-$ center-of-mass energy around 10.58 GeV with the BABAR detector at the PEP-II storage ring. In all 14 decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range $(0.7-4.8)\times 10^{-7}$ at 90% confidence level. All results are preliminary.Comment: 17 pages, 2 postscript figures, submitted to Tau0

Measurement of the CKM angle gamma in B ->D(*)0K decays with a Dalitz analysis of D0->KS pi- pi+

We present a measurement of the Cabibbo-Kobayashi-Maskawa CP-violating phase gamma with a Dalitz analysis of neutral D-meson decays to the K^0_s pi^- pi^+ final state from B^+/- -> D^{(*)}K^+/- decays, using a sample of 347 million B\bar{B} events collected by the BaBar detector. We measure gamma = (92 +/- 41 +/- 11 +/- 12)deg, where the first error is statistical, the second is the experimental systematic uncertainty and the third reflects the Dalitz model uncertainty. For the ratios r_B^{(*)} between the magnitudes of amplitudes A(B- -> D^{(*)0}K-) and A(B- ->\bar{D}^{(*)0} K-) we obtain the one-standard deviation intervals [0,0.14] and [0.02,0.20], respectively. All results presented here are preliminary.Comment: 21 pages, 6 figures. Contributed to the 33rd International Conference on High-Energy Physics, ICHEP 06, Mosco

A Measurement of the Neutral B Meson Lifetime using Partially Reconstructed B0 --> D*-pi+ Decays

The neutral B meson lifetime has been measured with the data collected by the BABAR detector at the PEP-II storage ring during the year 2000 for a total integrated luminosity of 20.3 fb-1. The B0 --> D*- pi+ decays have been selected with a partial reconstruction method in which only the fast pion from the B0 decay and the slow pion from D*- --> D0 bar pi- are reconstructed. The B0 lifetime has been measured to be 1.510 +/- 0.040 +/- 0.038 ps with a sample of 6971 +/- 241 reconstructed signal events.Comment: 15 pages, 2 postscript figures, submitted to XXXVII Moriond QC

Measurement of Branching Ratios and CP Asymmetries in B- -> D0(CP)K- Decays

We present preliminary results of the analysis of B -> D0 h decays, with h = pi, K and the D0 reconstructed in the channels K- pi+, K- pi+ pi+ pi-, K- pi+ pi0 and in the CP eigenstate K-K+, using data collected by the BABAR detector during the years 2000-2002 at the PEP-II asymmetric-energy B Factory at SLAC. We have measured the ratio of the branching fractions R = Br(B- -> D0 K-) / Br(B- -> D0 pi-) = (8.31 +- 0.35 (stat) +- 0.20 (syst))% and the direct CP asymmetry A(CP) = (Br(B- -> D0(CP) K-) - Br(B+ -> D0(CP) K+)) / (Br(B- -> D0(CP) K-)+Br(B+ -> D0(CP) K+)) = 0.17 +- 0.23 (stat) +0.09 -0.07 (syst).Comment: 17 pages, 8 postscript figures, submitted to ICHEP 2002 Conferenc

Search for the Lepton-Flavor Violating Decays Upsilon(3S) -> e tau and Upsilon(3S) -> mu tau

Charged lepton-flavor violating processes are extremely rare in the Standard Model, but they may occur in several beyond-the-Standard Model theories, including Supersymmetry or models with leptoquarks or compositeness. We present a search for such processes in a sample of 117M Upsilon(3S) decays recorded with the BaBar detector. We place upper limits on the branching fractions BF(Upsilon(3S) -> e tau) mu tau) < 4.1e-6 at 90% confidence level. These results are used to place lower limits on the mass scale of beyond-the-Standard Model physics contributing to lepton-flavor violating decays of the Upsilon(3S).Comment: 15 pages, 4 postscript figures, submitted to QWG

Measurement of branching fraction and CP asymmetries in B->D0(cp)K decays

We present a preliminary study of $B^- \to D^0_{CP} \pi^-$ and $B^- \to D^0_{CP} K^-$ decays, with the $D^0_{CP}$ reconstructed in the CP-odd eigenstates $K_s \pi^0$, $K_s \omega$, in the CP-even eigenstates $K^+ K^-$, $\pi^+ \pi^-$, and in the (non-CP) flavor eigenstate $K^\mp \pi^\pm$. Using a sample of about 382 million Y(4S) decays into BBbar pairs, collected with the BABAR detector operating at the PEP-II asymmetric-energy B Factory at SLAC, we measure the ratios of the branching fractions R_CP+- and the direct CP asymmetries A_CP+-. The results are: R_CP- = 0.81 \pm 0.10 (stat) \pm 0.05 (syst) R_CP+ = 1.07 \pm 0.10 (stat) \pm 0.04 (syst) A_CP- = -0.19 \pm 0.12 (stat) \pm 0.02 (syst) A_CP+ = 0.35 \pm 0.09 (stat) \pm 0.05 (syst)Comment: 17 pages, 15 postscript figures, contributed to Lepton Photon 200

Measurement of cos(2beta) in B0 -> D(*)0 h0 decays with a time-dependent Dalitz plot analysis of D0 -> Ks pi+ pi-

We report a preliminary measurement of $\cos2\beta$ in $B^0\to D^{(*)0}h^0$ decays with a time-dependent Dalitz plot analysis of $D^0\to K_S\pi^+\pi^-$, where $h^0$ is a light neutral meson such as $\pi^0$, $\eta$, $\eta'$ or $\omega$. The strong phase variation on the Dalitz plot allows the access to the angle $\beta$ with only a two-fold ambiguity ($\beta+\pi$). Using $311\times 10^{6}$ $B\bar{B}$ pairs collected at the Babar detector, we obtain $\cos2\beta = 0.54 \pm 0.54 \pm 0.08 \pm 0.18$, $\sin2\beta = 0.45 \pm 0.36 \pm 0.05 \pm 0.07$, and $|\lambda| = 0.975^{+0.093}_{-0.085} \pm 0.012 \pm 0.002$, where the first errors are statistical, the second are experimental systematic uncertainties, and the third are the signal Dalitz model uncertainties. This measurement favors the solution of $\beta= 22^\circ$ over $68^\circ$ at an 87% confidence level.Comment: 20 pages, 8 postscript figues, submitted to ICHEP200

Search for the D_(sJ)(2632)^+ at BaBar

We have performed a search for the $D^*_{sJ}(2632)^+$ state recently reported by the SELEX Collaboration at FNAL. This preliminary analysis makes use of an integrated luminosity of 125 ${\rm fb}^{-1}$ collected by the BaBar detector at the PEP-II asymmetric-energy $e^+e^-$ collider. The resulting $D_s \eta$ and $D^0 K^+$ mass spectra show no evidence for the $D^*_{sJ}(2632)^+$ state. In addition, no signal is observed in the $D^{*+} K_S$ mass spectrum.Comment: Submitted to the 32nd International Conference on High-Energy Physics Added C. Chen to author lis