889 research outputs found
Study of B -> \rho \pi decays at Belle
This paper describes a study of B meson decays to the pseudoscalar-vector
final state \rho\pi using 31.9\times 10^6 B\bar{B} events collected with the
Belle detector at KEKB. The branching fractions B(B^+ \to \rho^0\pi^+) =
(8.0^{+2.3+0.7}_{-2.0-0.7}) \times 10^{-6} and B(B^0 -> \rho^{+-} \pi^{-+}) =
(20.8^{+6.0+2.8}_{-6.3-3.1}) \times 10^{-6} are obtained. In addition, a 90%
confidence level upper limit of B(B^0 \to \rho^0\pi^0) < 5.3 \times 10^{-6}is
reported.Comment: 14 pages, 3 figures, to be submitted to Phys. Lett.
Cellulose acetate phthalate, a common pharmaceutical excipient, inactivates HIV-1 and blocks the coreceptor binding site on the virus envelope glycoprotein gp120
BACKGROUND: Cellulose acetate phthalate (CAP), a pharmaceutical excipient used for enteric film coating of capsules and tablets, was shown to inhibit infection by the human immunodeficiency virus type 1 (HIV-1) and several herpesviruses. CAP formulations inactivated HIV-1, herpesvirus types 1 (HSV-1) and 2 (HSV-2) and the major nonviral sexually transmitted disease (STD) pathogens and were effective in animal models for vaginal infection by HSV-2 and simian immunodeficiency virus. METHODS: Enzyme-linked immunoassays and flow cytometry were used to demonstrate CAP binding to HIV-1 and to define the binding site on the virus envelope. RESULTS: 1) CAP binds to HIV-1 virus particles and to the envelope glycoprotein gp120; 2) this leads to blockade of the gp120 V3 loop and other gp120 sites resulting in diminished reactivity with HIV-1 coreceptors CXCR4 and CCR5; 3) CAP binding to HIV-1 virions impairs their infectivity; 4) these findings apply to both HIV-1 IIIB, an X4 virus, and HIV-1 BaL, an R5 virus. CONCLUSIONS: These results provide support for consideration of CAP as a topical microbicide of choice for prevention of STDs, including HIV-1 infection
Measurements of Branching Fractions and Polarization in B > K^* rho Decays
We present results of a study of the charmless vector-vector decays B^0 ->
K^{*0} rho^0 and B^+ ->K^{*0} rho^+. The results are based on a 140 fb^{-1}
data sample collected by the Belle detector at the KEKB asymmetric e^+e^-
collider. We obtain the branching fraction B(B^+ -> K^{*0} rho^+)=(6.6 +-
2.2(stat.) +- 0.8 (syst.)) x 10^{-6}, and set upper limits on the branching
fractions B(B^0 -> K^{*0} rho^0) f_0(980)
K^{*0})<5.2 x 10^{-6}. We also perform a helicity analysis of the rho and K^*
vector mesons in the decay B^+ -> K^{*0} rho^+, and obtain the longitudinal
polarization fraction R_0(B^+ -> K^{*0} rho^+)=0.50 +-
0.19(stat.)+0.05-0.07}(syst.).Comment: 11 pages, 4 figures, submitted to ICHEP04, Beijing, Chin
Evidence of B0 --> rho0 pi0
We present the first evidence of the decay B0 --> rho0 pi0, using 140fb^-1 of
data collected at the Upsilon(4S) resonance with the Belle detector at the KEKB
asymmetric e+e- collider. We detect a signal with a significance of 3.5
standard deviations, and measure the branching fraction to be Br(B0 ->- rho0
pi0) = (5.1 +/- 1.6(stat) +/- 0.9(syst))*10^-6.Comment: RevTex4, 5 pages, 4 figures, submitted to Phys.Rev.Let
Charge Asymmetry of Same-Sign Dileptons in - Mixing
We report a measurement of the charge asymmetry for same-sign dileptons in
- mixing, . The data were collected with the Belle
detector at KEKB. Using a data sample of 78 fb recorded at the
resonance and 9 fb recorded at an energy 60 MeV below the
resonance, we measure .Comment: 21 pages, 9 figures, 3 tables, submitted to Physical Review
Measurements of the resonance properties
We report measurements of the properties of the and
resonances produced in continuum annihilation near
. The analysis is based on an data sample collected %at and 60 MeV below the
resonance with with the Belle detector at KEKB. We determine the masses to be
and . We observe the radiative decay mode
and the dipion decay mode , and determine their branching fractions. No corresponding
decays are observed for the state. These results are consistent
with the spin-parity assignments of for the and for
the .Comment: 5 pages, 6 figures; Added content, updated and paper submitted to PR
Search for the b --> d gamma process
We report the results of a search for the flavor-changing neutral current
process b --> d gamma using a sample of 275 million B meson pairs accumulated
by the Belle detector at KEKB. We find no significant signal for the exclusive
decays B- --> rho- gamma, B0B --> rho0 gamma, or B0B --> omega gamma. Assuming
an isospin relation between the three modes, we set an upper limit for the
combined branching fraction Br(B --> (rho,omega) gamma) < 1.4 x 10-6 at the 90%
confidence level. This limit can be used to constrain the ratio of CKM matrix
elements |Vtd/Vts|.Comment: 6 pages, 2 figures, submitted to Phys. Rev. D (RC
Observation of Large CP Violation and Evidence for Direct CP Violation in B0-->pi+pi- Decays
We report the first observation of CP-violating asymmetries in B0 --> pi+pi-
decays based on a 140 fb-1 data sample collected at the Upsilon(4S) resonance
with the Belle detector at the KEKB asymmetric-energy e+e- collider. We
reconstruct one neutral B meson as a B0 --> pi+pi- CP eigenstate and identify
the flavor of the accompanying B meson from its decay products. We apply an
unbinned maximum likelihood fit to the distribution of the time intervals
between the two B meson decay points. The fit yields the CP-violating asymmetry
amplitudes Apipi = +0.58+/-0.15(stat)+/-0.07(syst) and Spipi =
-1.00+/-0.21(stat)+/-0.07(syst). We rule out the CP-conserving case,
Apipi=Spipi=0, at a level of 5.2 standard deviations. We also find evidence for
direct CP violation with a significance at or greater than 3.2 standard
deviations for any Spipi value.Comment: 9 pages, 3 figure
Observation of the DsJ(2317) and DsJ(2457) in B decays
We report the first observation of the B --> Dbar DsJ(2317) and B --> Dbar
DsJ(2457) decays based on 123.8 10^6 BBar events collected with the Belle
detector at KEKB. We observe the DsJ(2317) decay to Ds pi0 and DsJ(2457) decay
to the Ds* pi0 and Ds gamma final states. We also set 90% CL upper limits for
the decays DsJ(2317) --> Ds* gamma, DsJ(2457) --> Ds* gamma, DsJ(2457) --> Ds
pi0 and DsJ(2457) --> Ds pi+ pi-.Comment: 6 pages, 3 figures. A few minor corrections. Replaced by version
accepted to publication in Phys. Rev. Let
Measurement of Branching Fraction and CP Asymmetry in B+ ->rho+ pi0
We report a measurement of the branching fraction for the decay based on a 140 data sample collected with the
Belle detector at the KEKB asymmetric collider. We measure the
branching fraction , and the CP-violating
asymmetry .Comment: 5 pages, 3 figures; submitted to Phys. Rev. Let
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