42,068 research outputs found
Cosmological Implications of 5-dimensional Brans-Dicke Theory
The five dimensional Brans-Dicke theory naturally provides two scalar fields
by the Killing reduction mechanism. These two scalar fields could account for
the accelerated expansion of the universe. We test this model and constrain its
parameter by using the type Ia supernova (SN Ia) data. We find that the best
fit value of the 5-dimensional Brans-Dicke coupling contant is .
This result is also consistent with other observations such as the baryon
acoustic oscillation (BAO).Comment: 5 pages, 4 figures, PLB accepte
QCD and Relativistic Corrections to Hadronic Decays of Spin-Singlet Heavy Quarkonia and
We calculate the annihilation decay widths of spin-singlet heavy quarkonia
and } into light hadrons with both QCD and relativistic
corrections at order in nonrelativistic QCD. With
appropriate estimates for the long-distance matrix elements by using the
potential model and operator evolution method, we find that our predictions of
these decay widths are consistent with recent experimental measurements. We
also find that the corrections are small for
states but substantial for states. In particular, the negative
contribution of correction to the decay can lower
the decay width, as compared with previous predictions without the
correction, and thus result in a good agreement with the
recent BESIII measurement.Comment: version published in PRD, 30 pages, 8 figures, more discussions on
LDMEs adde
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