Date: Sat, 01 Apr 2000 18:44:54 +0200 (CEST)
From: Antonio Bueno <abueno@pcnometh1.cern.ch>
Subject: comments to Nufact document
To: sgeer@fnal.gov
Cc: Andre.Rubbia@cern.ch, campanel@pcnometh3.cern.ch
Message-id: <Pine.LNX.4.10.10004011840210.29364-100000@pcnometh1.cern.ch>
MIME-version: 1.0
Content-type: TEXT/PLAIN; charset=US-ASCII


   Dear Steve Geer, 

please find below the comments and impressions I have about the
"Physics at a Neutrino Factory" draft you have successfully edited.

First of all, I congratulate you for the impressive and outstanding effort 
you've done in order to produce this document. It conveys in a most 
remarkable way the physics case at a neutrino factory. 

A few comments are due: 

-Inside the author list M. Campanelli is referenced as ETH Honggerberg 
while A. Rubbia and myself are assigned to the Institute fur
Teilchenphysik 
at ETHZ. 

 The correct reference, for the three of us, to our institution would be: 
 
 Institut f\"ur Teilchenphysik, ETHZ, CH-8093, Z\"urich, Switzerland. 

>> done


-Page 12, Table 1. Rates are given in kt-yr for nu_mu CC and anti-nue CC 
for different baselines and energies assuming 10^20 mu- decays. 

I understand that in order to be consistent with the numbers quoted in 
the table, all of the assumed 10^20 muon decay in the straight 
section pointing to the actual detector location. This implies 
that 2 x 10^20 muons are circulating in the ring. 

On the other hand, if only 10^20 muons are stored in the ring, the quoted 
rates should be divided by a factor two. 

In order to avoid misunderstandings and inconsistencies I think that 
in the caption should be clearly stated the number of muons circulating 
in the ring and the number of useful decays corresponding to the quoted 
rates.

>> We can only really talk about the number of decays in the
>> straight section ... the relationship between that and the
>> number of muons in the ring depends on the ring design.
>> To be clear we have updated the table caption to say numbers
>> correspond to 10^20 "useful" decays.

-Page 21, oscillation formula for nu-mu to nu-tau conversion in the 
one mass scale approximation is wrong. The amplitude of the oscillation 
in formula number 30 should read: 

 \sin^2 (2\theta_{23}) \cos^4 (\theta_{13}) 

while in the paper is written
 \sin^2 (2\theta_{13}) \cos^2 (\theta_{13}) 

>> fixed


-Table 5 in page 35: 

For the scenario labeled IB1, it is quoted that ICANOE cannot detect nu-mu 
to nu-e oscillations. We considered this is not correct, since the studies 
we performed for the ICANOE proposal showed that for a mass difference of 
0.4 eV$^2$ and sin^2 2\theta_{LSND} = 0.025 (in fact quite similar to 
your assumptions for scenario IB1), we expect a large electron 
appearance signal at energies below 30 GeV when compared to background 
expectations due to the natural nu-e beam contamination.

>>  done

- Page 45: reference to figure where a nu-e CC event, as detected by
ICANOE, 
is shown. The figure itself is assigned number 20, while in the text 
is referred as Figure 3.4.2

>> done

Also in this page the last setence reads: Electrons and photons can 
be identified event by event and their energies are measured ...

I think it should better read: Electrons and photons can 
be identified and their energies are measured ...

>> done

-Page 46: The paragraph refering to the dimensions and active mass of the 
ICANOE detector should be removed, since it gives the baseline design for 
an ICANOE detector at the CNGS beam and therefore it is incosistent with 
our assumptions for the physics case at a neutrino factory, where an
ICANOE 
detector with 10 kton fiducial mass was considered.

>> Rather than remove this text it would be better to update
>> the numbers to correspond to the 10 kt simulated. If we 
>> could get the updated numbers that would be great !

- Table 8, page 56, gives angular resolutions for the muon and 
hadronic shower that are not consistent with the parameterization we used 
in our studies. In fact we used an angular resolution of 

130 mrad / sqrt(p) for each hadron and the muon

>> done

-Page 72: First setence reads: 

Fig 38 for a 10kton ICANOE ... in which there are 10^20 mu^+ decays 
followed by 10^20 mu^- decays. 

This is inconsistent with fig 38 where the sensitivity on theta_13 is 
shown for 10^20 and 10^21 muon decays of each polarity. Therefore the 
end of the setence should be erased.

>> My master copy of draft 1 doesnt seem to have this for the fig. 38
>> caption ... so Im puzzled. Perhaps you can look at Drfat 2 and see
>> if the problem still persists, and let me know.

- Finally, page 122, reference 74 is written 

M. Campanelli et al., in preparation. 

I think that the proper reference to our work should read: 

A.Bueno, M. Campanelli, A. Rubbia, "Physics potential of an ICANOE-like 
detector at a neutrino factory", in preparation.

>> done

-----------------------oooooOOOOOOOOOOOOOOooooo-----------------------

Thank you very much in advance for taking into account the comments and 
considerations I wrote. 

Best wishes,

Antonio BUENO VILLAR                   
       CERN                          Inst fur Teilchenphysik
CH-1211, Geneve 23, Suisse         ETH-Honggerberg, 8093 Zurich    
e-mail: abueno@pcnometh1.cern.ch      phone: 41-22-767-1793