1,832 research outputs found
Final state phases in B -> D\pi, \bar{D}\pi decays and CP-asymmetry
Final state phases \delta_f and \delta_f' in B-> D pi, barD pi decays are
shown to be equal i.e. \delta =\delta_f-\delta_f' = 0. Thus CP-violating
asymmetry A(t) is independent of final state phases. The estimate for the
phases \delta_f and \delta_f' is also given.Comment: 6 pages, no figur
Determination of the CP Violating Phase by a Sum Over Common Decay Modes to and
To help the difficult determination of the angle of the unitarity
triangle, Aleksan, Dunietz and Kayser have proposed the modes of the type
, common to and . We point out that it is possible
to gain in statistics by a sum over all modes with ground state mesons in the
final state, i.e. , , , .
The delicate point is the relative phase of these different contributions to
the dilution factor of the time-dependent asymmetry. Each contribution to
is proportional to a product where
denotes form factors and decay constants. Within a definite phase
convention, lattice calculations do not show any change in sign when
extrapolating to light quarks the form factors and decay constants. Then, we
can show that all modes contribute constructively to the dilution factor,
except the -wave , which is small. Quark model arguments
based on wave function overlaps also confirm this stability in sign. By summing
over all these modes we find a gain of a factor 6 in statistics relatively to
. The dilution factor for the sum is remarkably stable for
theoretical schemes that are not in very strong conflict with data on or extrapolated from semileptonic charm form factors, giving
, always close to .Comment: 22 pages, LPTHE Orsay 94/03, DAPNIA/SPP/94-2
Phenomenological discussion of decays in QCD improved factorization approach
Trying a global fit of the experimental branching ratios and CP-asymmetries
of the charmless decays according to QCD factorization, we find it
impossible to reach a satisfactory agreement, the confidence level (CL) of the
best fit is smaller than .1 %. This failure reflects the difficulty to
accommodate several large experimental branching ratios of the strange
channels. Furthermore, experiment was not able to exclude a large direct CP
asymmetry in , which is predicted very small by QCD
factorization. Proposing a fit with QCD factorization complemented by a
charming-penguin inspired model we reach a best fit which is not excluded by
experiment (CL of about 8 %) but is not fully convincing.
These negative results must be tempered by the remark that some of the
experimental data used are recent and might still evolve significantly.Comment: 8 pages, 2 figures (requires epsfig, psfrag),talk presented at the
XXXVIIIth Rencontres de Moriond: Electroweak Interactions and Unified
Theories,Les Arcs, France, March 15-22, 2003. To be published in the
Proceeding
TLEP, first step in a long-term vision for HEP
The discovery of H(126) has renewed interest in circular e+e- colliders that
can operate as Higgs factories, which benefit from three unique
characteristics: i) high luminosity and reliability, ii) the availability of
several interaction points, iii) superior beam energy accuracy. TLEP is an e+e-
storage ring of 80-km circumference that can operate with very high luminosity
from the Z peak (90 GeV) to the top quark pair threshold (350 GeV). It can
achieve transverse beam polarization at the Z peak and WW threshold, giving it
unparalleled accuracy on the beam energy. A preliminary study indicates that an
80 km tunnel could be constructed around CERN. Such a tunnel would allow a 100
TeV proton-proton collider to be established in the same ring (VHE-LHC),
offering a long term vision.Comment: This is a contribution to the the Snowmass process 2013: Frontier
Capabilitie
Hunting for the alpha: , ,
The hypothesis of the smallness of penguin contribution to charmless
strangeless decays allows to determine with high accuracy the
value of angle from the currently available , and decay data.Comment: 9 page
Comments on "Wall-plug (AC) power consumption of a very high energy e+/e- storage ring collider" by Marc Ross
The paper arXiv:1308.0735 questions some of the technical assumptions made by
the TLEP Steering Group when estimating in arXiv:1305.6498 the power
requirement for the very high energy e+e- storage ring collider TLEP. We show
that our assumptions are based solidly on CERN experience with LEP and the LHC,
as well accelerators elsewhere, and confirm our earlier baseline estimate of
the TLEP power consumption.Comment: 6 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 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 . There are no
penguin contributions to these decays. It is possible that will be the second function of CP phases, after , to be
measured at B-factories.Comment: 4 pages, RevTeX, no figure
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