3,729 research outputs found
Final-State Phases in Baryon-Antibaryon Decays
The recent observation of the decay \ob \to \Lambda_c^+ \bar p suggests
that related decays may soon be visible at colliders. It is shown how
these decays can shed light on strong final-state phases and amplitudes
involving the spectator quark, both of which are normally expected to be small
in B decays.Comment: 14 pages, LaTeX, 2 figures, submitted to Phys. Rev. D, references and
discussion of helicity amplitudes adde
Strong Phases and Factorization for Color Suppressed Decays
We prove a factorization theorem in QCD for the color suppressed decays B0->
D0 M0 and B0-> D*0 M0 where M is a light meson. Both the color-suppressed and
W-exchange/annihilation amplitudes contribute at lowest order in LambdaQCD/Q
where Q={mb, mc, Epi}, so no power suppression of annihilation contributions is
found. A new mechanism is given for generating non-perturbative strong phases
in the factorization framework. Model independent predictions that follow from
our results include the equality of the B0 -> D0 M0 and B0 -> D*0 M0 rates, and
equality of non-perturbative strong phases between isospin amplitudes,
delta(DM) = delta(D*M). Relations between amplitudes and phases for M=pi,rho
are also derived. These results do not follow from large Nc factorization with
heavy quark symmetry.Comment: 38 pages, 6 figs, typos correcte
Relating Final State Interactions in and
A Regge model calculation relates the strong phase in to that in
. This provides a significant test of a hadronic picture of final
state interactions in B decays.Comment: 8 pages and 1 eps figur
Chiral doublers of heavy-light baryons
We discuss the consequences of the chiral doubling scenario for baryons built
of heavy and light quarks. In particular, we use the soliton description for
baryons, demonstrating why each heavy-light baryon should be accompanied by the
opposite parity partner. Our argumentation holds both for ordinary baryons and
for exotic heavy pentaquarks which are required by the symmetries of QCD to
appear in parity doublets, seperated by the mass shift of the chiral origin.
Interpreting the recently observed by BaBaR, CLEO and Belle charmed mesons with
assignment as the chiral partners of known and mesons,
allows us to estimate the parameters of the mesonic effective lagrangian, and
in consequence, estimate the masses of ground states and excited states of both
parities. In particular, we interpret the state recently reported by the H1
experiment at HERA as a chiral partner of yet
undiscovered ground state pentaquark .Comment: 10 pages, in v2 some typos corrected, references adde
Measurement of the Pion Form Factor in the Energy Range 1.04-1.38 GeV with the CMD-2 Detector
The cross section for the process is measured in the
c.m. energy range 1.04-1.38 GeV from 995 000 selected collinear events
including 860000 events, 82000 events, and 33000
events. The systematic and statistical errors of measuring the
pion form factor are equal to 1.2-4.2 and 5-13%, respectively.Comment: 5 pages, 2 figure
Study of the process in the c.m. energy range from threshold to 2 GeV with the CMD-3 detector
Using a data sample of 6.8 pb collected with the CMD-3 detector at the
VEPP-2000 collider we select about 2700 events of the process and measure its cross section at 12 energy ponts with about
6\% systematic uncertainty. From the angular distribution of produced nucleons
we obtain the ratio
Measurement of the cross section with the CMD-3 detector at the VEPP-2000 collider
The process has been studied in the
center-of-mass energy range from 1500 to 2000\,MeV using a data sample of 23
pb collected with the CMD-3 detector at the VEPP-2000 collider.
Using about 24000 selected events, the cross
section has been measured with a systematic uncertainty decreasing from 11.7\%
at 1500-1600\,MeV to 6.1\% above 1800\,MeV. A preliminary study of
production dynamics has been performed
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