35 research outputs found
Measurement of the branching fraction
The branching fraction is measured in a data sample
corresponding to 0.41 of integrated luminosity collected with the LHCb
detector at the LHC. This channel is sensitive to the penguin contributions
affecting the sin2 measurement from The
time-integrated branching fraction is measured to be . This is the most precise measurement to
date
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of
prime importance in probing new physics. Here 7421 +/- 105 signal events from
the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp
collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A
time-dependent fit to the data yields a value of
phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard
Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201
Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) and the direct CP asymmetry in B0 -> K*0 gamma
The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma
and Bs0 phi gamma has been measured using an integrated luminosity of 1.0 fb-1
of pp collision data collected by the LHCb experiment at a centre-of-mass
energy of sqrt(s)=7 TeV. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 ->
phi gamma) = 1.23 +/- 0.06(stat.) +/- 0.04(syst.) +/- 0.10(fs/fd), where the
first uncertainty is statistical, the second is the experimental systematic
uncertainty and the third is associated with the ratio of fragmentation
fractions fs/fd. Using the world average value for BR(B0 -> K*0 gamma), the
branching fraction BR(Bs0 -> phi gamma) is measured to be (3.5 +/- 0.4) x
10^{-5}.
The direct CP asymmetry in B0 -> K*0 gamma decays has also been measured with
the same data and found to be A(CP)(B0 -> K*0 gamma) = (0.8 +/- 1.7(stat.) +/-
0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the
previous experimental results and theoretical expectations.Comment: 21 pages, 3 figues, 4 table
First observation of the decay and a measurement of the ratio of branching fractions
The first observation of the decay using
data collected by the LHCb detector at a centre-of-mass energy of 7 TeV,
corresponding to an integrated luminosity of 36 pb, is reported. A
signal of events is obtained and the absence of signal is
rejected with a statistical significance of more than nine standard deviations.
The branching fraction is measured relative to
that of : , where the first uncertainty is statistical, the second systematic and
the third is due to the uncertainty on the ratio of the and
hadronisation fractions.Comment: 10 pages, 3 figures, submitted to Phys. Lett. B; ISSN 0370-269
Distância morfológica entre genótipos de trigo com ausência e presença do caráter "stay-green"
Efeito da temperatura do solo na infectividade e reprodução det Meloidogyne javanica e Heterodera glycines em cultivares de soja
Observation of CP violation in B+ to DK+ decays
An analysis of B+ to DK+ and B+ to Dpi+ decays is presented where the D meson
is reconstructed in the two-body final states: K+pi-, K+K-, pi+pi- and pi+K-.
Using 1.0 fb-1 of LHCb data, measurements of several observables are made
including the first observation of the suppressed mode B+ to DK+, D to pi+K-.
CP violation in B+ to DK+ decays is observed with 5.8 sigma significance
Measurement of the Ds+ - Ds- production asymmetry in 7 TeV pp collisions
Heavy quark production in 7 TeV centre-of-mass energy pp collisions at the
LHC is not necessarily flavour symmetric. The production asymmetry, A_P,
between Ds+ and Ds- mesons is studied using the \phi\pi(+/-) decay mode in a
data sample of 1.0/fb collected with the LHCb detector. The difference between
\pi+ and \pi- detection efficiencies is determined using the ratios of fully
reconstructed to partially reconstructed D*(+/-) decays. The overall production
asymmetry in the Ds rapidity region 2.0 to 4.5 with transverse momentum larger
than 2 GeV is measured to be A_P=(-0.33 +/- 0.22 +/- 0.10)%. This result can
constrain models of heavy flavour production.Comment: 13 pages, 10 figures, updated to published versio