593 research outputs found
Evidence for a new magnetic field scale in CeCoIn5
The Nernst coefficient of CeCoIn5 displays a distinct anomaly at H_K ~ 23 T.
This feature is reminiscent of what is observed at 7.8 T in CeRu2Si2, a
well-established case of metamagnetic transition. New frequencies are observed
in de Haas-van Alphen oscillations when the field exceeds 23 T, which may
indicate a modification of the Fermi surface at this field.Comment: submitted to Physical Review Letter
Analysis of electrodeposited nano-scale copper wire microstructure by EBSD method
The high-resolution electron backscatter diffraction (EBSD) technique was applied to study electrodeposited and subsequently annealed nano-scale copper wires. The mean grain size was found to be coarser than the mean free path of electrons (~ 40 nm). The wires were shown to contain a notable fraction of low-angle boundaries as well as annealing twins. The material was found have a strong {111} texture
Measurement of branching fraction and direct asymmetry in charmless decays at Belle
We report a study of the charmless hadronic decay of the charged meson to
the three-body final state . The results are based on a data
sample that contains pairs collected at the
resonance with the Belle detector at the KEKB asymmetric-energy
collider. The measured inclusive branching fraction and the direct
asymmetry are and
, respectively, where the first uncertainties are
statistical and the second are systematic. The invariant mass
distribution of the signal candidates shows an excess in the region below
GeV/, which is consistent with the previous studies from BaBar and LHCb.
In addition, strong evidence of a large direct asymmetry is found in the
low-invariant-mass region.Comment: 7 pages, 3 figure
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
Inclusive study of bottomonium production in association with an meson in annihilations near
We study bottomonium production in association with an meson in
annihilations near the , at a center of mass energy of
GeV. The results are based on the fb data
sample collected by the Belle experiment at the asymmetric energy KEKB
collider. Only the meson is reconstructed and the missing-mass spectrum
of candidates is investigated. We observe the
process and find evidence for the
process, while no significant signals of
, , nor are found. Cross sections for the
studied processes are reported.Comment: Submitted to EPJ-
Search for decays with semileptonic tagging at Belle
We present the results of a search for the rare decays , where stands for and . The results are
obtained with pairs collected with the Belle
detector at the KEKB collider. We reconstruct one meson in a
semileptonic decay and require a single meson but nothing else on the
signal side. We observe no significant signal and set upper limits on the
branching fractions. The limits set on the , , , ,
, and channels
are the world's most stringent.Comment: Submitted to PR
Measurement of the lepton polarization and in the decay
We report the first measurement of the lepton polarization
in the decay as
well as a new measurement of the ratio of the branching fractions , where
denotes an electron or a muon, and the is reconstructed in the modes
and .
We use the full data sample of pairs recorded
with the Belle detector at the KEKB electron-positron collider. Our results,
and
, are
consistent with the theoretical predictions of the Standard Model.Comment: 7 pages, 2 figures, submitted to Physical Review Letters; one figure
was removed from the first versio
Cross sections and double-helicity asymmetries of midrapidity inclusive charged hadrons in p+p collisions at sqrt(s)=62.4 GeV
Unpolarized cross sections and double-helicity asymmetries of
single-inclusive positive and negative charged hadrons at midrapidity from p+p
collisions at sqrt(s)=62.4 GeV are presented. The PHENIX measurements for 1.0 <
p_T < 4.5 GeV/c are consistent with perturbative QCD calculations at
next-to-leading order in the strong coupling constant, alpha_s. Resummed pQCD
calculations including terms with next-to-leading-log accuracy, yielding
reduced theoretical uncertainties, also agree with the data. The
double-helicity asymmetry, sensitive at leading order to the gluon polarization
in a momentum-fraction range of 0.05 ~< x_gluon ~< 0.2, is consistent with
recent global parameterizations disfavoring large gluon polarization.Comment: PHENIX Collaboration. 447 authors, 12 pages, 5 figures, 5 tables.
Submitted to Physical Review
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