Comparison with Published Results
The following plot shows the comparison of the new CDF result with the previously published result
from
Run I [Phys. Rev. Lett. 88, 161802 (2002)],
which was performed with |y|<0.4.
The two results are consistent (χ2/dof~2.1/4).
Although the new result was performed for |y|<0.6, we find no evidence that the angular distribution changes
rapidly with the rapidity interval analyzed, at least in the central rapidity region.
Repeating the new analysis, but restricting it to |y|<0.4, we obtain the following
comparison:
which is also consistent with the Run I result (χ2/dof~2.0/4).
The following plot compares the new CDF result with the D∅ result
for the ϒ(1S)[Phys. Rev. Lett. 101, 182004 (2008)].
The D∅ result has the open symbols.
The two results are inconsistent at the level of about 4.5σ.
The following plot compares the new CDF result with the D∅ result for the ϒ(2S).
The D∅ result has the open symols.
In these comparisons, the yellow bands indicates the range of α(≡ λθ) predicted
by NRQCD [Phys. Rev. D63, 071501(R) (2001)].
The two magenta curves show two extreme cases of the kT factorization model
[JETP Lett. 86, 435 (2007)]. The upper (dashed) curve assumes complete de-polarization
of the ϒ(1S) when produced in the decay of χb states,
while the lower (solid) curve assumes that the polarization is preserved.