4,606 research outputs found
Observation of and Evidence for
We report the first observation of and first
evidence for , which are CP eigenstate decay modes.
These results are obtained from of data collected at
the resonance with the Belle detector at the KEKB
collider. We measure the branching fractions with a significance of , and
with a significance of . The last error
listed is due to uncertainty in the number of produced pairs.Comment: 5 pages, 2 figures, 2 tables, published in PR
Vitellogenin Underwent Subfunctionalization to Acquire Caste and Behavioral Specific Expression in the Harvester Ant Pogonomyrmex barbatus
PMCID: PMC3744404This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication
Measurement of eta_c(1S), eta_c(2S) and non-resonant eta' pi+ pi- production via two-photon collisions
We report the measurement of gamma gamma to eta_c(1S), eta_c(2S) to eta' pi+
pi- with eta' decays to gamma rho and eta pi+ pi- using 941 fb^{-1} of data
collected with the Belle detector at the KEKB asymmetric-energy e+e- collider.
The eta_c(1S) mass and width are measured to be M = [2984.6\pm0.7 (stat.)\pm2.2
(syst.)] MeV/c^{2} and \Gamma = [30.8^{+2.3}_{-2.2}~(stat.) \pm 2.5~(syst.)]
MeV, respectively. First observation of eta_c(2S) to eta' pi+ pi- with a
significance of 5.5sigma including systematic error is obtained, and the
eta_c(2S) mass is measured to be M = [3635.1\pm3.7~(stat.)\pm2.9~(syst.)]
MeV/c^{2}. The products of the two-photon decay width and branching fraction
(B) of decays to eta'pi+ pi- are determined to be \Gamma_{gamma gamma}B =
[65.4\pm2.6~(stat.)\pm6.9~(syst.)] eV for eta_c(1S) and
[5.6^{+1.2}_{-1.1}~(stat.)\pm1.1~(syst.)] eV for eta_c(2S). A new decay mode
for the eta_c(1S) to eta'f_0(2080) with f_0(2080) to pi+ pi- is observed with a
statistical significance of 20sigma. The f_0(2080) mass and width are
determined to be M = [2083^{+63}_{-66}~(stat.)\pm 32~(syst.)] MeV/c^{2} and
\Gamma = [178^{+60}_{-178}~(stat.) \pm 55~(syst.)] MeV. The cross sections for
gamma gamma to eta' pi+ pi- and eta'f_{2}(1270) are measured for the first
time.Comment: 19 pages, 14 figure
Experimental Tests of Neutron Shielding for the ATLAS Forward Region
Experimental tests devoted to the optimization of the neutron shielding for the ATLAS forward region were performed at the CERN-PS with a 4 GeV/c proton beam. Spectra of fast neutrons, slow neutrons and gamma rays escaping a block of iron (404080 cm) shielded with different types of neutron and gamma shields (pure polyethylene - PE, borated polyethylene - BPE, lithium filled polyethylene - LiPE, lead, iron) were measured by means of plastic scintillators, a Bonner spectrometer, a HPGe detector and a slow neutron detector. Effectiveness of different types of shielding agaisnt neutrons and -rays were compared. The idea of a segmented outer layer shielding (iron, BPE, iron, LiPE) for the ATLAS Forward Region was also tested
Bounds on the width, mass difference and other properties of X(3872) --> pi+pi-J/psi decays
We present results from a study of X(3872) --> pi+pi- J/psi decays produced
via exclusive B--> K X(3872) decays. We determine the mass to be M_X(3872)=
(3871.84\pm 0.27 (stat)\pm 0.19 (syst)) MeV, a 90% CL upper limit on the
natural width of Gamma_X(3872)
K+X(3872))xBf(X(3872)-->pi+pi-J/psi)=(8.61 \pm 0.82(stat) \pm 0.52 (syst))
x10^{-6}, and a ratio of branching fractions Bf(B0--> K0 X(3872))/BF(B+--> K+
X(3872))=0.50\pm 0.14(stat)\pm0.04(syst). The difference in mass between the
X(3872)-->pi+pi-J/psi signals in B+ and B0 decays is Delta M_{X(3872)= (-0.69
\pm 0.97 (stat)} \pm 0.19 (syst)) MeV. A search for a charged partner of the
X(3872) in the decays Bbar0-->K- X+ or B+-->K0X+, X+-->pi+pi0 J/psi resulted in
upper limits on the product branching fractions for these processes that are
well below expectations for the case that the X(3872) is the neutral member of
an isospin triplet. In addition, we examine possible J^{PC} quantum number
assignments for the X(3872) based on comparisons of angular correlations
between final state particles in X(3872)-->pi+pi-J/psi decays with simulated
data for J^{PC} values of 1^{++} and 2^{-+}. We examine the influence of
rho-omega interference in the M(pi+pi-) spectrum. The analysis is based on a
711fb^{-1} data sample that contains 772 million BBbar meson pairs collected at
the Upsilon(4S) resonance in the Belle detector at the KEKB e+e- collider.Comment: 15 pages, 10 figures and 6 tables. Submitted to Physical Review
Evidence for a new resonance and search for the Y(4140) in
The process \gamma \gamma \to \phi \jpsi is measured for \phi \jpsi
masses between threshold and 5 GeV/, using a data sample of 825
fb collected with the Belle detector. A narrow peak of
events, with a significance of 3.2 standard deviations
including systematic uncertainty, is observed. The mass and natural width of
the structure (named X(4350)) are measured to be
and
, respectively. The
product of its two-photon decay width and branching fraction to \phi\jpsi is
for , or
for . No
signal for the Y(4140)\to \phi \jpsi structure reported by the CDF
Collaboration in B\to K^+ \phi \jpsi decays is observed, and limits of
\Gamma_{\gamma \gamma}(Y(4140)) \BR(Y(4140)\to\phi \jpsi)<41 \hbox{eV} for
or for are determined at the 90% C.L. This
disfavors the scenario in which the Y(4140) is a molecule.Comment: 9 pages, 3 figures, publication in Phys. Rev. Lett. 104, 112004, 201
Observation of an alternative candidate in
We perform a full amplitude analysis of the process , where refers to either or . A new
charmoniumlike state that decays to is observed with a
significance of . Its mass is ()
MeV/ and width is () MeV. The
hypothesis is favored over the hypothesis at the level
of . The analysis is based on the 980 data sample
collected by the Belle detector at the asymmetric-energy collider
KEKB.Comment: 17 pages, 11 figure
Search for the Glueball in and decays
We report the first search for the glueball in
and decays with data samples of million and
million events, respectively, collected with the Belle detector. No
significant signals are observed in any of the proposed production modes, and
the 90\% credibility level upper limits on their branching fractions in
and decays are obtained. The inclusive branching
fractions of the and decays into final states
with a are measured to be \BR(\Upsilon(1S)\to \chi_{c1}+ anything)
= (1.90\pm 0.43(stat.)\pm 0.14(syst.))\times 10^{-4} with an improved
precision over prior measurements and \BR(\Upsilon(2S)\to \chi_{c1}+ anything)
= (2.24\pm 0.44(stat.)\pm 0.20(syst.))\times 10^{-4} for the first time.Comment: 19 pages, 17 figures, Fig.10b was polished, but all the results
unchanged. Paper was published in PR
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