3,049 research outputs found
Tests of Factorization and SU(3) Relations in B Decays into Heavy-Light Final States
Using data from the B factories and the Tevatron, we perform tests of how
well non-leptonic B decays of the kind B -> D^{(*)}_{(s)} P, where P is a pion
or kaon, are described within the factorization framework. We find that
factorization works well - as is theoretically expected - for color-allowed,
tree-diagram-like topologies. Moreover, also exchange topologies, which have a
non-factorizable character, do not show any anomalous behavior. We discuss also
isospin triangles between the B -> D^{(*)} pi decay amplitudes, and determine
the corresponding amplitudes in the complex plane, which show a significant
enhancement of the color-suppressed tree contribution with respect to the
factorization picture. Using data for B -> D^{(*)} K decays, we determine
SU(3)-breaking effects and cannot resolve any non-factorizable SU(3)-breaking
corrections larger than \sim 5%. In view of these results, we point out that a
comparison between the \bar B^0_d -> D^+\pi^- and \bar B^0_s -> D_s^+\pi^-
decays offers an interesting new determination of f_d/f_s. Using CDF data, we
obtain the most precise value of this ratio at CDF, and discuss the prospects
for a corresponding measurement at LHCb.Comment: 12 pages, 6 figures, matches published version in Physical Review 
3+1 dimensional Yang-Mills theory as a local theory of evolution of metrics on 3 manifolds
An explicit canonical transformation is constructed to relate the physical
subspace of Yang-Mills theory to the phase space of the ADM variables of
general relativity. This maps 3+1 dimensional Yang-Mills theory to local
evolution of metrics on 3 manifolds.Comment: 7 pages, revte
Branching ratio measurements of decays
We have just entered an era of precision measurements for 
OT FE-Box Test Procedures
The OT FE readout requirements is the precise (~0.5 ns) and efficient drift time measurement at an occupancy of ~4% to ensure single hit resolution. The acquired achievement of such performance on an assembled FE-Box is verify through a final test performed using a special FE-Tester. In this note the test procedures are described
Observation of the decay
The decay  is observed for the first
time, using proton-proton collisions collected with the LHCb detector
corresponding to an integrated luminosity of 3fb. A signal yield of
 decays is reported with a significance of 6.2 standard deviations.
The ratio of the branching fraction of \B_c \rightarrow J/\psi K^+ K^- \pi^+
decays to that of  decays is measured to be
, where the first uncertainty is statistical and the
second is systematic.Comment: 18 pages, 2 figure
Observation of resonances consistent with pentaquark states in decays
Observations of exotic structures in the  channel, that we refer to
as pentaquark-charmonium states, in  decays are
presented. The data sample corresponds to an integrated luminosity of 3/fb
acquired with the LHCb detector from 7 and 8 TeV pp collisions. An amplitude
analysis is performed on the three-body final-state that reproduces the
two-body mass and angular distributions. To obtain a satisfactory fit of the
structures seen in the  mass spectrum, it is necessary to include two
Breit-Wigner amplitudes that each describe a resonant state. The significance
of each of these resonances is more than 9 standard deviations. One has a mass
of  MeV and a width of  MeV, while the second
is narrower, with a mass of  MeV and a width of  MeV. The preferred  assignments are of opposite parity, with one
state having spin 3/2 and the other 5/2.Comment: 48 pages, 18 figures including the supplementary material, v2 after
  referee's comments, now 19 figure
Measurements of the branching fractions of B+→ppK+ decays
The branching fractions of the decay B+ → pp̄K+ for different intermediate states are measured using data, corresponding to an integrated luminosity of 1.0 fb-1, collected by the LHCb experiment. The total branching fraction, its charmless component Mpp̄ < 2.85 GeV/c2 and the branching fractions via the resonant cc̄ states η c(1S) and ψ(2S) relative to the decay via a J/ψ intermediate state are [Equation not available: see fulltext.] Upper limits on the B + branching fractions into the η c(2S) meson and into the charmonium-like states X(3872) and X(3915) are also obtained
Observation of the decay B+c→Bºsπ+
The result of a search for the decay B+c→Bºsπ+ is presented, using the Bºs→Ds-π+ and Bºs→J/ψϕ channels. The analysis is based on a data sample of pp collisions collected with the LHCb detector, corresponding to an integrated luminosity of 1  fb-1 taken at a center-of-mass energy of 7 TeV, and 2  fb-1 taken at 8 TeV. The decay B+c→Bºsπ+ is observed with significance in excess of 5 standard deviations independently in both decay channels. The measured product of the ratio of cross sections and branching fraction is [σ(Bc+)/σ(Bºs)]×B(Bc+→Bºsπ+)=[2.37±0.31 (stat)±0.11 (syst)-0.13+0.17(τBc+)]×10-3, in the pseudorapidity range 2<η(B)<5, where the first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty on the Bc+ lifetime. This is the first observation of a B meson decaying to another B meson via the weak interaction
Differential branching fraction and angular analysis of decays
The differential branching fraction of the rare decay  is measured as a function of , the
square of the dimuon invariant mass. The analysis is performed using
proton-proton collision data, corresponding to an integrated luminosity of 3.0
\mbox{ fb}^{-1}, collected by the LHCb experiment. Evidence of signal is
observed in the  region below the square of the  mass. Integrating
over 15 < q^{2} < 20 \mbox{ GeV}^2/c^4 the branching fraction is measured as
d\mathcal{B}(\Lambda^{0}_{b} \rightarrow \Lambda \mu^+\mu^-)/dq^2 = (1.18 ^{+
0.09} _{-0.08} \pm 0.03 \pm 0.27) \times 10^{-7} ( \mbox{GeV}^{2}/c^{4})^{-1},
where the uncertainties are statistical, systematic and due to the
normalisation mode, , respectively.
In the  intervals where the signal is observed, angular distributions are
studied and the forward-backward asymmetries in the dimuon ()
and hadron () systems are measured for the first time. In the
range 15 < q^2 < 20 \mbox{ GeV}^2/c^4 they are found to be A^{l}_{\rm FB} =
-0.05 \pm 0.09 \mbox{ (stat)} \pm 0.03 \mbox{ (syst)} and A^{h}_{\rm FB} =
-0.29 \pm 0.07 \mbox{ (stat)} \pm 0.03 \mbox{ (syst)}.Comment: 27 pages, 10 figures, Erratum adde
- …
