650 research outputs found

### Resolving a Discrete Ambiguity in the CKM Angle $\beta$ through $B_{u,d} \to J/\psi K^\ast$ and $B_s \to J/\psi \phi$ Decays

It is well known that $\sin(2\beta)$, where $\beta$ is one of the angles of
the unitarity triangle of the CKM matrix, can be determined in a theoretically
clean way by measuring mixing-induced CP violation in the decay $B_d \to J/\psi
K_S$. Another clean extraction of this CKM angle is provided by the
time-dependent angular distribution for the decay products of $B_d \to
J/\psi(\to l^+l^-) K^{\ast0}(\to \pi^0 K_S)$, where we have more observables at
our disposal than in the case of $B_d \to J/\psi K_S$, so that in addition to
$\sin(2\beta)$ also $\cos(2\beta)$ can be probed in a direct way. Unfortunately
a sign ambiguity remains in $\cos(2\beta)$. If it could be resolved, a discrete
ambiguity in the extraction of the CKM angle $\beta$ could be resolved as well,
which would allow a more incisive test of the CKM model of CP violation. This
note shows that detailed time-dependent studies of $B_{u,d} \to J/\psi
K^{\ast}$ and $B_s \to J/\psi \phi$ decay processes can determine the sign of
$\cos(2\beta)$, thereby removing the corresponding ambiguity in the extraction
of the CKM angle $\beta$.Comment: 5 pages, LaTeX, no figure

### CP Asymmetries in (Semi-)Inclusive B0 Decays

It was recently pointed out that inclusive B^0(t) decays could show CP
violation. The totally inclusive asymmetry is expected to be tiny [O(10^{-3})]
because of large cancellations among the asymmetries in the charmless, single
charm and double charm final states. Enriching particular final state
configurations could significantly increase the CP-asymmetry and observability.
Such studies can extract fundamental CKM (Cabibbo-Kobayashi-Maskawa)
parameters, and (perhaps) even Delta m(B_s). A superb vertex detector could see
CP violation with 10^5 (10^6) flavor-tagged B_s (B_d) mesons within the CKM
model. Because the effects could be significantly larger due to new physics,
they should be searched for in existing or soon available data samples.Comment: RevTex, 20 pages, no figure

### Current Topics in D0 B Physics

An overview of selected topics in DO B-Physics is presented, covering
relevant detector characteristics, and with emphasis on the most recent results
in the Bs, FCNC and rare decay programs.Comment: 4 pages, 3 figures, for the D0 Collaboration, 10th International
Conference on B-Physics at Hadron Machines - BEAUTY 2005 - June 20 to 24,
2005 in Assisi, Ital

### Yet another way to measure $\gamma$

We show that the CKM phase $2 \beta+\gamma$ can be extracted from measurement
of the time dependent rates in the decays $\bar{B}^0 \to D^{(*)\pm} M^\mp$ and
$B^0 \to D^{(*)\pm} M^\mp$, where $M=a_0$, $\pi(1300)$, $b_1$, $a_2$, $\pi_2$,
$\rho_3$. These channels have a large asymmetry between decays of $\bar{B}^0$
and $B^0$ into the same final state. Even though the branching ratios are
small, their sensitivity to $\gamma$ can be competitive with decays into
$D^{(*)}$ and $(\pi,\rho,a_1)$.Comment: 5 pages, some clarifications and references adde

### 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

### Implications of a Low sin(2 beta): A Strategy for Exploring New Flavor Physics

We explore the would-be consequences of a low value of the CP-violating phase
$\sin2\beta_{\psi K}$. The importance of a reference triangle obtained from
measurements that are independent of $B$--$\bar B$ and $K$--$\bar K$ mixing is
stressed. It can be used to extract separately potential New Physics
contributions to mixing in the $B_d$, $B_s$ and $K$ systems. We discuss several
constructions of this triangle, which will be feasible in the near future. The
discrete ambiguity is at most two-fold and eventually can be completely
removed. Simultaneously, it will be possible to probe for New Physics in
loop-dominated rare decays.Comment: 9 pages, 6 figure

### 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

### Clean CKM Information from Bd(t) -> D(*)+/- pi-/+

It has been known for many years that the Bd(t) -> D(*)+/- {pi-/+, rho-/+,
a1-/+} modes may involve observable CP violating effects. This note describes
how to determine cleanly the Cabibbo-Kobayashi-Maskawa (CKM) phase phi = -2
beta - gamma = -pi + alpha - beta, even in the presence of possible final state
interactions. A discrete ambiguity remains.Comment: 8 pages, revte

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