302 research outputs found

### Heavy Baryon Production and Decay

The branching ratio B(Lambda_c -> p K- pi+) normalizes the production and
decay of charmed and bottom baryons. At present, this crucial branching ratio
is extracted dominantly from B.bar -> baryons analyses. This note questions
several of the underlying assumptions and predicts sizable B.bar -> D(*) N
N'.bar X transitions, which were traditionally neglected. It predicts
B(Lambda_c -> p K- pi+) to be significantly larger (0.07 +/- 0.02) than the
world average. Some consequences are briefly mentioned. Several techniques to
measure B(Lambda_c -> p K- pi+) are outlined with existing or soon available
data samples. By equating two recent CLEO results, an appendix obtains B(D0 ->
K- pi+)= 0.035 +/- 0.002, which is somewhat smaller than the current world
average.Comment: 27 pages, 4 eps figures, revte

### Enhanced CP Violation with $B\to K D^0 (\overline D^0)$ Modes and Extraction of the CKM Angle gamma

The Gronau-London-Wyler (GLW) method extracts the CKM angle $\gamma$ by
measuring $B^\pm$ decay rates involving $D^0/\overline D^0$ mesons. Since that
method necessitates the interference between two amplitudes that are
significantly different in magnitude, the resulting asymmetries tend to be
small. CP violation can be greatly enhanced for decays to final states that are
common to both D^0 and $\overline D^0$ and that are not CP eigenstates. In
particular, large asymmetries are possible for final states f such that $D^0\to
f$ is doubly Cabibbo suppressed while $\overline D^0\to f$ is Cabibbo allowed.
The measurement of interference effects in two such modes allows the extraction
of $\gamma$ without prior knowledge of $Br(B^-\to K^- \overline D^0)$, which
may be difficult to determine due to backgrounds.Comment: 12 pages, LaTeX, no figure

### Theoretical correction to the neutral $B^0$ meson asymmetry

Certain types of asymmetries in neutral meson physics have not been treated
properly, ignoring the difference of normalization factors with an assumption
of the equality of total decay width. Since the corrected asymmetries in $B^0$
meson are different from known asymmetries by a shift in the first order of CP-
and CPT-violation parameters, experimental data should be analyzed with the
consideration of this effect as in $K^0$ meson physics.Comment: 7 page

### Extracting Weak Phase Information from B -> V_1 V_2 Decays

We describe a new method for extracting weak, CP-violating phase information,
with no hadronic uncertainties, from an angular analysis of B -> V_1 V_2
decays, where V_1 and V_2 are vector mesons. The quantity $\sin^2 (2\beta +
\gamma)$ can be cleanly obtained from the study of decays such as B_d^0(t) ->
D^{*\pm} \rho^\mp, D^{*\pm} a_1^{\mp}, D^{*0} K^{*0}, etc. Similarly, one can
use B_s^0(t) -> D_s^{*\pm} K^{*\mp} to extract $\sin^2 \gamma$. There are no
penguin contributions to these decays. It is possible that $\sin^2 (2\beta +
\gamma)$ will be the second function of CP phases, after $\sin 2\beta$, to be
measured at B-factories.Comment: 4 pages, RevTeX, no figure

### Improved Methods for Observing CP Violation in B+/- --> K+/- D0 and Measuring the CKM Phase gamma

Various methods are discussed for obtaining the CKM angle gamma through the
interference of the charged B-meson decay channels B- -> K- D0 and B- -> K-
D0-bar where the D0 and D0-bar decay to common final states. It is found that
choosing final states which are not CP eigenstates can lead to large direct CP
violation which can give significant bounds on gamma without any theoretical
assumptions. If two or more modes are studied, gamma may be extracted with a
precision on the order of +/-15 degrees given about 10^8 B-mesons. We also
discuss the case of three body decays of the D0 where additional information
may be obtained from the distribution of the D0 decay products and consider the
impact of D-D-bar oscillations.Comment: 51 pages 8 figures, typo in equation 33 correcte

### CP Violation and Lifetime Differences of Neutral B Mesons from Correlated B^0-B^0bar Pairs

We present a technique to determine the CP violating phases, as well as, the
lifetime differences of the mass eigenstates for both $B_d$ and $B_s$, by
considering correlated $B\bar{B}$ pairs produced at the $\Upsilon$ resonances.
We do not require a detailed time dependent study, but only partial time
integrated rates, with the tag time, either preceding or following the decay of
the other $B$ meson to a final state f. f may be a CP eigenstate or a non-CP
eigenstate.Comment: 11 Pages Revte

### Bose-Einstein Correlations for Mixed Neutral Mesons

Correlations are shown to arise in nonidentical mixed-particle pairs like
$K^o \bar K^o$ when observed in identical decay modes like $K_S K_S$ in
multiparticle final states containing many partial waves. No enhancement is
found in any single partial wave and all partial wave analyses of the s-wave
threshold resonance $a_o$ and $f_o$ should give the same results for all decay
modes. In CP violation experiments where $B^o - \bar B^o$ pairs are inclusively
produced and correlated decays into $\psi K_S$ and leptonic modes are observed,
the CP-violating lepton asymmetry is enhanced by a factor of two in the
kinematic region where Bose enhancement occurs.Comment: 11 page

### Framework for Identification of Neutral B Mesons

We introduce a method for the study of CP-violating asymmetries in tagged
states of neutral $B$ mesons with arbitrary coherence properties. A set of
time-dependent measurements is identified which completely specifies the
density matrix of the initial state in a two-component space with basis vectors
$B^0$ and $\overline B^0$, and permits a determination of phases in the
Cabibbo-Kobayashi-Maskawa matrix. For a given tagging configuration, the
measurement of decays both to flavor eigenstates and to CP eigenstates provides
the necessary information.Comment: Submitted to Phys. Rev. Letters. 8 pages, LaTeX, Technion-PH-93-31 /
EFI 93-3

### CP violation and CKM phases from angular distributions for $B_s$ decays into admixtures of CP eigenstates

We investigate the time-evolutions of angular distributions for $B_s$ decays
into final states that are admixtures of CP-even and CP-odd configurations. A
sizable lifetime difference between the $B_s$ mass eigenstates allows a probe
of CP violation in time-dependent untagged angular distributions. Interference
effects between different final state configurations of $B_s\to D^{*+}_s
D^{*-}_s$, $J/\psi \phi$ determine the Wolfenstein parameter $\eta$ from
untagged data samples, or -- if one uses $|V_{ub}|/|V_{cb}|$ as an additional
input -- the notoriously difficult to measure CKM angle $\gamma$. Another
determination of $\gamma$ is possible by using isospin symmetry of strong
interactions to relate untagged data samples of $B_s\to K^{\ast+} K^{\ast-}$
and $B_s\to K^{\ast0} \overline{K^{\ast0}}$. We note that the untagged angular
distribution for $B_s\to\rho^0 \phi$ provides interesting information about
electroweak penguins.Comment: 19 pages, LaTeX, no figure

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