E852 experiment
Analysis of Eta Pi0
system with the decay Eta -> Pi+ Pi- Pi0
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Draft 4
Date:
Thu, 14 Mar 2006,
From: Suh -Urk
Remarks Concerning the t' dependense
Response
I remind, that in two publication on EtaPi0
1)R. Lindenbusch's thesis, Fig.77 for a0(980)
2)A Dzierba et al.,PRD67(2003), Fig.29 for D0 wave
we see W(t) -> exp(-bt') at t'->0 in EtaPi0 data.
Our remarks
There is small mistake in text of draft4,
which will be corrected in draft5.
Ratio UNPE/NPE must be written as
n2*b1^2/(n1*b2)=0.71+/-0.03
because we calculated the integrals under curves.
In draft5 we remove a piece of text and fig.2 of draft4 concerning
the results of t' dependence fit. We agree Gary that Fig. 2 is not essential to the paper.
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Date:
Thu, 5 Apr 2006,
From: Suh -Urk
I have written an elementary account of the new decay amplitudes
which includes \tprime dependence, aimed at an audience with a casual interest i
n PWA's.
See the attached pdf file, and please comment.
In the meantime, let me make some additional remarks:
1) For our data with the proton recoil, the new forms of decay amplitudes may be unimportant,
because our trigger requirements selected only the events with "finite" valu
e of t.
2)However, the \tprime dependence may become important for neutron-recoil events.
For this reason, it may have an appreciable effect on the likelihood functions.
Can you run some additional PWA fits with the modified form? And thank you in advance.
Response
1.Such study with new decay amplitudes need a hard additional work.
a)Standart software of E852 PWA must be changed and it requests thorough checking.
b)We need to introduce the new free parameters t'_0 and t''_0 without understanding the regions of its values.
c)There are some theoretical questions. For example. Lets suppose that c is resonant state. We introduce additional t' dependence in its decay amplitude.
How to undestand that the decay angular distribution in resonance rest system will be dependent on t' with which the resonance was produced?
So, we suggest don't discuss t' dependence in paper and make the study of Suh Urk's suggestion in future.
3)I am very uneasy about different masses and widths we find for the \pi_1(1400
).
Is it possible that the modified forms of the decay amplitudes could shift t
he values around, possibly in the right direction? It is certainly worth trying...
4)My personal feeling, however, is that conflicting masses and widths of the \p
i_1(1400) point to existence of more than one exotic object in this mass region.
Response
This idea is good. If Eta and Pi0 are products of 4-quark system decay then,
may be, there is not one resonant state, but two or more with close mass, which we can't resolve. Let's Suh-Urk insert this idea in text.
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Date:
Thu, 13 Apr 2006,
From: Suh -Urk
Will please take out the reference 13
(S. U. Chung and E. Klempt).
We no longer feel very strongly about
the selection rule. We are writing
a followup article on this. Until then,
please take out the reference.
Response
Done