250 research outputs found

### Indirect search of exotic mesons: B -> J/psi + Anything

We reconsider the discrepancy between theory and data in the momentum
distribution of slow J/psi in B decays. Beside an update of the standard color
singlet and color octet QCD components, we include the contribution from XY Z
exotic mesons, and show that the residual discrepancy could be accommodated
considering new XYZ mesons still unobserved.Comment: 3 pages, 3 figures, Contribution to the proceedings of "IFAE 2011
Incontri di Fisica delle Alte Energie", Perugia 27-29 April 201

### The new hadrons: Molecules or tetraquarks?

We briefly discuss some new hints about X(3872) and Y (4660), which can help to unravel the pros and cons of the molecular and tetraquark interpretations proposed in these years

### Charmed Baryonium

We re-analyze the published data on the Y(4630) --> Lambda_c Lambdabar_c and
the Y(4660) --> psi(2S) pi pi with a consistent Ansatz and we find that the two
observations are likely to be due to the same state Y_B with M_{Y_B} = 4660.7
+- 8.7 MeV and Gamma_{Y_B} = 61 +- 23 MeV. Under this hypothesis and
reanalizing also the e+e- --> J/psi pi pi gamma_ISR spectrum we extract B(Y_B
--> Lambda_c Lambdabar_c) / B(Y_B --> psi(2S) pi pi) = 25 +- 7, B(Y_B --> J/psi
pi pi) / B(Y_B --> psi(2S) pi pi) J/psi pi pi)
/ B(Y(4350) --> psi(2S) pi pi) psi(2S)
sigma) / B (Y_B --> psi(2S) f_0)=2.0 +- 0.3. These conclusions strongly support
the hypothesis of Y_B being the first observation of a charmed baryonium
constituted by four quarks. From the analysis of the mass spectrum and the
decay properties we show that Y(4350) and Y_B are respectively consistent with
the ground state and first radial excitation of the L=1 state.Comment: Corrected phase space normalization in the fit

### The 2^-+ assignment for the X(3872)

Very recently the BaBar collaboration has put forward a claim that the
X(3872) is not a 1^++ resonance, as most of the phenomenological work on the
subject was relying on, but rather a 2^-+ one. We examine the consequences of
this quantum number assignment for the solution of the X(3872) puzzle. The
molecular interpretation appears less likely, and the conventional charmonium
interpretation should be reconsidered. There are several well-known
difficulties with this interpretation, to which we add a new one: the
production cross section at CDF is predicted to be much smaller than that
observed. We also confirm, using a relativistic string model, the conclusion
from potential models that the mass of the state is not consistent with
expectations. In the tetraquark interpretation the 2^-+ assignment implies a
rich spectrum of partner states, although the X(3872) may be among the few
which are narrow enough to be observable.Comment: 18 pages, 6 figures, 4 tables; minor style corrections. Version to
appear in PR

### The momentum distribution of J/psi in B decays

The discrepancy between theory and data in the momentum distribution of slow
J/psi in B decays has been several times addressed as a puzzle. Using the most
recent results on exclusive B decays into J/psi and heavy kaons or exotic
mesons and reconsidering the non-relativistic-QCD calculation of the color
octet fragmentation component, we show that an improvement in the comparison
between data and theory can be obtained. There is still room for a better fit
to data and this may imply that new exotic mesons of the XYZ kind have yet to
be discovered.Comment: 4 pages, 2 figures, 2 tables. To appear in Physical Review

### Strong Couplings of X(3872)_{J=1,2} and a New Look at J/psi Suppression in Heavy Ion Collisions

We define and compute from data the strong couplings of the X(3872) with both
of the possible quantum numbers assignments J^{PC}=1^{++},2^{-+}. We use these
to compute cross sections for J/psi resonance scattering into D Dbar*. As an
application of the results obtained we revise the calculation of the J/psi
absorption in a hot hadron gas to confront with recent RHIC observations in
Au-Au collisions.Comment: 23 pages, 18 figures, 4 table

### More loosely bound hadron molecules at CDF?

In a recent paper we have proposed a method to estimate the prompt production
cross section of X(3872) at the Tevatron assuming that this particle is a
loosely bound molecule of a D and a D*bar meson. Under this hypothesis we find
that it is impossible to explain the high prompt production cross section found
by CDF at sigma(X(3872)) \sim 30-70 nb as our theoretical prediction is about
300 times smaller than the measured one. Following our work, Artoisenet and
Braaten, have suggested that final state interactions in the DD*bar system
might be so strong to push the result we obtained for the cross section up to
the experimental value. Relying on their conclusions we show that the
production of another very narrow loosely bound molecule, the X_s=D_s D_s*bar,
could be similarly enhanced. X_s should then be detectable at CDF with a mass
of 4080 MeV and a prompt production cross section of sigma(X_s) \sim 1-3 nb.Comment: Minor revisions made. To appear in Phys Lett

### Is the X(3872) Production Cross Section at Tevatron Compatible with a Hadron Molecule Interpretation?

The X(3872) is universally accepted to be an exotic hadron. In this letter we
assume that the X(3872) is a D0 \bar D0* molecule, as claimed by many authors,
and attempt an estimate of its prompt production cross section at Tevatron. A
comparison with CDF data allows to draw some qualitative conclusions about this
statement.Comment: 4 pages, 4 figures, accepted for publication in Phys. Rev. Let

### Abortion in America: How Legislative Overreach Is Turning Reproductive Rights Into Criminal Wrongs

This report outlines current legal statutes that criminalize abortion and the impact overturning Roe v. Wade would have on laws to prosecute and incarcerate those providing, receiving, or assisting with abortions. It details the risk that, without protections provided by Roe v. Wade, many states can and will continue to pass laws that further inflame the national crisis of overcriminalization and mass incarceration

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