8,211 research outputs found
Search for Pentaquarks at BABAR
The results of searches for the strange pentaquark states, Theta(1540)+,
Xi(1860)-- and Xi(1860)0 in data recorded by the BABAR experiment are
presented. We search for these three states inclusively in 123.4 fb^-1 of e+ e-
annihilation data produced at the PEP-II asymmetric storage rings; we find no
evidence for their production in any physics process, and set limits on their
production rates that are well below the measured rates for conventional
baryons. We also search for Theta(1540)+ produced in interactions of electrons
or hadrons in the material of the inner part of the detector. No evidence for
this state is found in a sample with much higher statistics than similar
electroproduction experiments that claim a signal.Comment: 4 pages, 4 postscript figues, contributed to the Proceedings of QCD
05, Montpellie
Artfilms, Handicrafts and Other Cultural Goods: The Case for Subsidy
Though widespread, the practice of public subsidies for cultural activity lacks a rigorous and consistent economic rationale. We analyze a canonical market structure that characterizes much cultural activity: the competition of mass-produced goods with heterogeneous non- standardized goods that are imperfect substitutes. We analyze several types of market failure: uncertainty about preferences (we do not know what we like, and we do not know what we might like in the future); endogeneity of preferences (we like what our neighbors talk about, and we like what we're accustomed to); and externalities associated with production (future production costs are determined by current production). The model provides a basis for cultural subsidies to promote social welfare and economic development.
Time Reversal Violation from the entangled B0-antiB0 system
We discuss the concepts and methodology to implement an experiment probing
directly Time Reversal (T) non-invariance, without any experimental connection
to CP violation, by the exchange of "in" and "out" states. The idea relies on
the B0-antiB0 entanglement and decay time information available at B factories.
The flavor or CP tag of the state of the still living neutral meson by the
first decay of its orthogonal partner overcomes the problem of irreversibility
for unstable systems, which prevents direct tests of T with incoherent particle
states. T violation in the time evolution between the two decays means
experimentally a difference between the intensities for the time-ordered (l^+
X, J/psi K_S) and (J/psi K_L, l^- X) decays, and three other independent
asymmetries. The proposed strategy has been applied to simulated data samples
of similar size and features to those currently available, from which we
estimate the significance of the expected discovery to reach many standard
deviations.Comment: 17 pages, 2 figures, 6 table
Nonleptonic charmless two-body decays
In this work we have studied hadronic charmless two-body B decays involving
p-wave mesons in final state. We have calculated branching ratios of
decays (where and denotes a axial-vector and a tensor meson,
respectively), using form factors obtained in the covariant
light-front (CLF) approach, and the full effective Hamiltonian. We have
obtained that ,
,
(with ) for ,
with
, for
where . It seems that these decays can be measured
in experiments at factories. Additionally, we have found that
and
ratios could be useful to determine numerical values of mixing angles
and , respectively.Comment: 12 page
Understanding the newly observed Y(4008) by Belle
Very recently a new enhancement around 4.05 GeV was observed by Belle
experiment. In this short note, we discuss some possible assignments for this
enhancement, i.e. and molecular state. In these two
assignments, Y(4008) can decay into with comparable
branching ratio with that of . Thus one suggests
high energy experimentalists to look for Y(4008) in channel.
Furthermore one proposes further experiments to search missing channel
, and especially and
, which will be helpful to distinguish and
molecular state assignments for this new enhancement.Comment: 4 pages, 5 figures. Typos correcte
Constraint on the CKM angle alpha from the experimental measurements of CP violation in B_d^0 --> pi^+ pi^- decay
In this paper, we study and try to find the constraint on the CKM angle alpha
from the experimental measurements of CP violation in B_d^0 --> pi^+ pi^-
decay, as reported very recently by BaBar and Belle Collaborations. After
considering uncertainties of the data and the ratio r of penguin over tree
amplitude, we found that strong constraint on both the CKM angle alpha and the
strong phase delta can be obtained from the measured CP asymmetries S_{pi pi}
and A_{pi pi}: (a) the ranges of 87 degrees <= alpha <= 131 degrees and 36
degrees <= delta <= 144 degrees are allowed by 1 sigma of the averaged data for
r = 0.31; (b) for Belle's result alone, the limits on alpha and delta are 104
degrees <= alpha <= 139 degrees and 42 degrees <= delta <= 138 degrees for 0.32
<= r <= 0.41; and (c) the angle alpha larger than 90 degrees is preferred.Comment: Revtex, 17 pages with 6 ps/eps figure files, new Babar data Reported
at ICHEP 2002 considere
Accounting for Slow J/psi from B Decay
A slow J/psi excess exists in the inclusive B -> J/psi+X spectrum, and is
indicative of some hadronic effect. From color octet nature of c cbar pair in
b-> c cbar s decay, one such possibility would be B -> J/psi+ K_g decay, where
K_g is a hybrid resonance with sbar g q constituents. We show that a K_g
resonance of ~ 2 GeV mass and suitably broad width could be behind the excess.Comment: 4 pages, 2 figures. To appear in Phys. Rev.
Radiative and Semileptonic B Decays Involving Higher K-Resonances in the Final States
We study the radiative and semileptonic B decays involving a spin-
resonant with parity for and for
in the final state. Using the large energy effective theory (LEET)
techniques, we formulate transition form factors in the large
recoil region in terms of two independent LEET functions
and , the values of
which at zero momentum transfer are estimated in the BSW model. According to
the QCD counting rules, exhibit a dipole
dependence in . We predict the decay rates for ,
and . The
branching fractions for these decays with higher -resonances in the final
state are suppressed due to the smaller phase spaces and the smaller values of
. Furthermore, if the spin of
becomes larger, the branching fractions will be further suppressed due to the
smaller Clebsch-Gordan coefficients defined by the polarization tensors of the
. We also calculate the forward backward asymmetry of the decay, for which the zero is highly insensitive to the
-resonances in the LEET parametrization.Comment: 27 pages, 4 figures, 7 tables;contents and figures corrected, title
and references revise
Light hadron, Charmonium(-like) and Bottomonium(-like) states
Hadron physics represents the study of strongly interacting matter in all its
manifestations and the understanding of its properties and interactions. The
interest on this field has been revitalized by the discovery of new light
hadrons, charmonium- and bottomonium-like states. I review the most recent
experimental results from different experiments.Comment: Presented at Lepton-Photon 2011, Mumbai, India; 21 pages, 18 figures;
add more references; some correctio
What can we learn from phi_1 and B_d^0 -> pi^+ pi^- ?
We discuss what we can understand from and
decay mode. Using a convention without weak phases and , we
can solve the parameters from the time-depended CP asymmetry. If we can put a
condition the contribution from penguin except for the CKM factor including in
the diagram is small, then we can lead the allowed region of or
by using the convention.Comment: 7 pages, 4 figures, references and comments adde
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