Additional physics topics

Date: Tue, 28 Nov 1995 11:58:56 -0600 (CST)
From: "Jorge G. Morfin" 
Subject: WANTED: Additional Physics Topics to be Studied with the Near Detector
To: minos_all@FNAL.FNAL.GOV
Cc: JORGE@fnalv.fnal.gov
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Dear Colleagues,

        Although the physics of oscillating neutrinos is the prime interest
and what originally brought us together as the MINOS collaboration, it is
certainly not the only physics we can study with the huge sample of
neutrino events we will have at the near detector site.    Before
specifying the details of the detectors at the near site we should consider
all the possible physics topics we could study with a properly designed
spectrometer.

        The original concept of the near detectors contained a steel
calorimeter, which would be a smaller version of the far detector, and a
beam monitor calorimeter which would be a fine-sampling calorimeter for
beam monitoring and studies.  The current situation was summarized by Jenny
Thomas at our last collaboration meeting when she pointed out that, with
the expected statistics, the energy and position of the beam are already
adequately determined in the steel calorimeter.  The remaining advantages
of the fine-sampling calorimeter as a beam monitor would then be as a more
sensitive electron neutrino detector and, possibly, as a way to more
accurately measure the neutrino angle.  The major point of this note is
that, in addition to its role as a beam monitor, a fine-sampling
calorimeter could be a very rich source of additional physics results.

        Leaving concerns about cost and technical difficulty for a
subsequent step, I would like to collect your response to the questions:
what physics other than oscillation phenomena can we study with an intense
neutrino/anti-neutrino beam, both wide band and narrow band, produced by
120 GeV protons and what detector technologies are needed to study it?  To
start the dialogue the following are general ideas from an earlier study by
Bob Bernstein and Ray Brock dealing with electroweak topics and from
studies of nuclear QCD my colleagues and I performed in the Tevatron muon
experiment (E-665).

                1) nu_mu + e ---> nu_mu + e:    Can we get enough
statistics with a narrow band beam to determine sin^2 theta_W using the
y-distribution.  The alternative method of determining y involves a
quadratic dependence on  theta_e which requires extremely good angular
resolution.  How difficult is it to achieve the necessary angular
resolution so we might also use the much larger wide band leptonic neutral
current sample?

                2) Nuclear Structure Functions: Shadowing, anti-shadowing
and the EMC effect are well studied phenomena in charged lepton
experiments.  With neutrino beams there have been only relatively low
statistics inconclusive studies of these nuclear effects.  There is still a
multi-sigma disagreement between the low-x values of F2 from the NMC muon -
deuterium data and from CCFR neutrino-iron data once the CCFR data are
converted to deuterium values using A-scaling parameters taken from MUON
scattering results.  Are nuclear efects that different in neutrino
scattering compared to muon scattering?  The expected statistics at the
near detector appear to be sufficient to permit sections of low-, medium- and
high-A targets within a single spectrometer allowing us to study a wide
range of neutrino induced nuclear effects.  Can we cover the necessary
range in x_Bj and Q^2?

                3) Longitudinal Structure functions:  Another very
difficult measurement which could be performed in narrow band beam
exposures.

        If we could design an affordable spectrometer which would enable a
more detailed study of the hadron shower we could also consider the
following.

                5) Diffractive scattering/rapidity-gap studies:  We
established a connection between shadowing and diffractive production in
E-665 .  How does this change when we exchange a W instead of a virtual
photon?

                6) Color transparency:  Is color transparency a final state
phenomena dependent only on the size of the bound quarks or is it
dependent on what carries the 4-momentum from lepton to parton?

                7)  Hadron formation length:  How far do partons travel
before they become a hadron?

        Now that I've tossed out ideas ranging from easily achievable to
wildly exotic/expensive you should have no inhibitions in suggesting ideas
you think we should consider.  Please send them to me and I will organize
them for a presentation at our next collaboration meeting.  Thank you.

                                                Best regards,
                                                   Jorge