166 research outputs found

    Study of multi-muon events produced in p\bar{p} interactions at \sqrt{s}=1.96 TeV

    Get PDF
    68 pages, 46 figures, 11 tables. Submitted to Phys. Rev. D. Removed typos from the authors' listWe report the results of a study of multi-muon events produced at the Fermilab Tevatron collider and acquired with the CDF II detector using a dedicated dimuon trigger. The production cross section and kinematics of events in which both muon candidates are produced inside the beam pipe of radius 1.5 cm are successfully modeled by known processes which include heavy flavor production. In contrast, we are presently unable to fully account for the number and properties of the remaining events, in which at least one muon candidate is produced outside of the beam pipe, in terms of the same understanding of the CDF II detector, trigger, and event reconstruction.Peer reviewe

    Search for the highly suppressed decays B- -> K+π-π- and B- -> K-K-π+

    Get PDF
    We report a search for the decays B- -> K+pi(-)pi(-) and B- -> K-K-pi(+), which are highly suppressed in the standard model. Using a sample of (467 +/- 5) x 10(6) B (B) over bar pairs collected with the BABAR detector, we do not see any evidence of these decays and determine 90% confidence level upper limits of B(B- -> K+pi(-)pi(-)) and K-K-pi(+)) and < 1.6 x 10(-7) on the corresponding branching fractions, including systematic uncertainties

    Aqueously altered igneous rocks sampled on the floor of Jezero crater, Mars

    No full text
    The Perseverance rover landed in Jezero crater, Mars, to investigate ancient lake and river deposits. We report observations of the crater floor, below the crater?s sedimentary delta, finding the floor consists of igneous rocks altered by water. The lowest exposed unit, informally named Séítah, is a coarsely crystalline olivine-rich rock, which accumulated at the base of a magma body. Fe-Mg carbonates along grain boundaries indicate reactions with CO2-rich water, under water-poor conditions. Overlying Séítah is a unit informally named Máaz, which we interpret as lava flows or the chemical complement to Séítah in a layered igneous body. Voids in these rocks contain sulfates and perchlorates, likely introduced by later near-surface brine evaporation. Core samples of these rocks were stored aboard Perseverance for potential return to Earth

    Search for B-0 meson decays to pi(KSKS0)-K-0-K-0, eta(KSKS0)-K-0, and eta(KSKS0)-K-'-K-0

    No full text
    We describe searches for B-0 meson decays to the charmless final states pi(KSKS0)-K-0-K-0, eta(KSKS0)-K-0, and eta(KSKS0)-K-'-K-0. The data sample corresponds to 467x10(6) BB pairs produced in e(+)e(-) annihilation and collected with the BABAR detector at the SLAC National Accelerator Laboratory. We find no significant signals and determine the 90% confidence level upper limits on the branching fractions, in units of 10(-7), B(B-0 ->pi(KSKS0)-K-0-K-0)eta(KSKS0)-K-0)eta(KSKS0)-K-'-K-0)< 20

    Measurement of CP violation observables and parameters for the decays B-+/--> DK*+/-

    No full text
    We study the decay B--> DK*- using a sample of 379x10(6) Upsilon(4S)-> BB events collected with the BABAR detector at the PEP-II B factory. We perform a Gronau-London-Wyler analysis where the D meson decays into either a CP-even (CP+) eigenstate (K+K-, pi(+)pi(-)), CP-odd (CP-) eigenstate (K-S(0)pi(0), K-S(0)phi, K-S(0)omega) or a non-CP state (K-pi(+)). We also analyze D meson decays into K+pi(-) from a Cabibbo-favored D-0 decay or doubly suppressed D-0 decay [Atwood-Dunietz-Soni (ADS) analysis]. We measure observables that are sensitive to the Cabibbo-Kobayashi-Maskawa angle gamma: the partial-rate charge asymmetries A(CP +/-), the ratios R-CP +/- of the B-decay branching fractions in CP +/- and non-CP decay, the ratio R-ADS of the charge-averaged branching fractions, and the charge asymmetry A(ADS) of the ADS decays: A(CP+)=0.09 +/- 0.13 +/- 0.06, A(CP-)=-0.23 +/- 0.21 +/- 0.07, RCP+=2.17 +/- 0.35 +/- 0.09, RCP-=1.03 +/- 0.27 +/- 0.13, R-ADS=0.066 +/- 0.031 +/- 0.010, and A(ADS)=-0.34 +/- 0.43 +/- 0.16, where the first uncertainty is statistical and the second is systematic. Combining all the measurements and using a frequentist approach yields the magnitude of the ratio between the Cabibbo-suppressed and favored amplitudes, r(B)=0.31 with a one (two) sigma confidence level interval of [0.24, 0.38] ([0.17, 0.43]). The value r(B)=0 is excluded at the 3.3 sigma level. A similar analysis excludes values of gamma in the intervals [0, 7]degrees, [55, 111]degrees, and [175, 180]degrees ([85, 99]degrees) at the one (two) sigma confidence level

    Correlated leading baryon-antibaryon production in e(+)e(-) -> c(c)over-bar -> Lambda(+)(c)(Lambda)over-bar(c)(-)X

    No full text
    We present a study of 649 +/- 35 e(+)e(-) -> c (c) over bar events produced at root s approximate to 10.6 GeV containing both Lambda(+)(c) baryon and a (Lambda) over bar (-)(c) antibaryon. The number observed is roughly 4 times that expected if the leading charmed hadron types are uncorrelated, confirming an observation by the CLEO Collaboration. We find a 2-jet topology in these events but very few additional baryons, demonstrating that the primary c and (c) over bar are predominantly contained in a correlated baryon-antibaryon system. In addition to the charmed baryons we observe on average 2.6 +/- 0.2 charged intermediate mesons, predominantly pions, carrying 65% of the remaining energy

    Study of hadronic transitions between Y states and observation of Y(4S) -> eta Y(1S) decay

    Get PDF
    We present a study of hadronic transitions between Y(mS) (m = 4, 3, 2) and Y(nS) (n = 2, 1) resonances based on 347.5 fb(-1) of data taken with the BABAR detector at the PEP-II storage rings. We report the first observation of Y(4S) -> eta Y(1S) decay with a branching fraction B(Y(4S) -> eta Y(1S) = (1.96 +/- 0.06(stat) +/- 0.09(syst)) X 10(-4) and measure the ratio of partial widths Gamma(Y(4S) -> eta Y(1S))/Gamma(Y(4S) -> pi(+)pi Y-(1S)) = 2.41 +/- 0.40(stat) +/- 0.12(syst). We set 90% CL upper limits on the ratios Gamma(Y(2S) -> eta Y(1S))/Gamma(Y(2S) -> pi(+)pi Y-(1S) eta Y(1S)/Gamma(Y(3S) -> pi(+)pi Y-(1S)) pi(+)pi Y-(2S)/Gamma(Y(4S) -> pi(+)pi Y-(1S)) = 1.16 +/- 0.16(stat) +/- 0.14(syst) and Gamma(Y(3S) -> pi(+)pi Y-(1S)) = 0.577 +/- 0.026(stat) +/- 0.060(syst)

    Improved Limits on Lepton-Flavor-Violating tau Decays to l phi, l rho, lK*, and l(K)over-bar*

    Get PDF
    We search for the neutrinoless, lepton-flavor-violating tau decays tau(-)-> l(-) V-0, where l is an electron or muon and V-0 is a vector meson reconstructed as phi -> K+ K-, rho -> pi(+) pi(-), K* -> K+ pi(-), (K) over bar*-> K- pi(+). The analysis has been performed using 451 fb(-1) of data collected at an e(+) e(-) center-of-mass energy near 10.58 GeV with the BABAR detector at the PEP-II storage rings. The number of events found in the data is compatible with the background expectation, and upper limits on the branching fractions are set in the range (2.6-19) x 10(-8) at the 90% confidence level.We are grateful for the excellent luminosity and machine conditions provided by our PEP-II colleagues, and for the substantial dedicated effort from the computing organizations that support BABAR. The collaborating institutions wish to thank SLAC for its support and kind hospitality. This work is supported by DOE and NSF (USA), NSERC (Canada), CEA and CNRS-IN2P3(France), BMBF and DFG (Germany), INFN (Italy), FOM (The Netherlands), NFR (Norway), MES (Russia), MEC (Spain), and STFC (United Kingdom). Individuals have received support from the Marie Curie EIF (European Union) and the A. P. Sloan Foundation.Peer reviewe
    corecore