[MUSIC PLAYING]
LOW: Good afternoon.
Our speakers this afternoon, of
course, need no introduction.
Let me just say a
few words anyway.
We live in a time of
rising expectations.
And we physicists, I
think, are no exception
to what is going on in
the rest of the world.
Our expectations
are rising also.
There's talk of a crisis
in elementary particle
physics, nothing to do,
technological unemployment.
Where are we going to go?
All of those questions--
Of course, the crisis--
it's not really a crisis.
It's a reflection of
the tremendous success
that this field has had
over the last decade.
46 years ago-- the
date we're celebrating,
the date we're
remembering, 46 years ago--
it would have been
inconceivable to imagine
that we would have the
understanding, the knowledge
of the subnuclear
world that we now have.
So it's hardly a
crisis in that sense.
It's a wonderful accomplishment.
It's been reflected a great deal
in the talks that we've heard.
Today, we have four
speakers, all of whom
played major parts in
achieving this success
and learning the
things that we've
learned over the last 25 years.
It's an honor to
have them with us.
Looking at the
titles, it seems to me
the first three speakers
are addressing the present,
the past, and the future.
And the last, Steve, is
addressing all of the above.
So we'll see.
The first speaker is
Professor Sam Ting.
And his title is, "Muons,
Electrons, and Gamma Rays."
Sam.
TING: It's 25 years
ago, Viki hired me.
At that time, I had
quite a few offers.
MIT was the only
offer without tenure.
But nevertheless, I sensed their
great freedom for research,
and, therefore, I
decided to come here.
In any case, I did
not really understand
what tenure was in the case.
What I would like to
do today, in order not
to waste your time, is
to describe a little bit
the sense Professor Becker,
Professor Min Chen, and others
have been doing, together
with me, on physics
of the electrons,
muons, and photons.
The first period
covers from '65 to '72,
in the Deutches Elektonen
Synchrotron in Hamburg.
My personal interest
in this field
comes from reading a paper from
Columbia, by Francis Low, whom
I did not know at that time, on
the possibility of an excited
electron [? go to econ. ?]
And that paper
fascinated me a great deal.
As you all know, the physics of
the electron positron, in fact,
[INAUDIBLE] this morning,
already since '48, '49,
and '50s, through the work
of Deutsch and Kendall
and others, who have the
simplest electron positron
collider.
And that is positronium.
In 1964, there was an
experiment that shows
electrodynamics was violated.
The experiment that
was carried out
was a photoproduction of
the electron positron pair
in the field of
Coloumb nucleus, where
you have a momentum transfer,
so-called Bethe-Heitler pair,
a momentum transfer of 1 TeV.
And therefore, you probe the
electron propagator to 10
to the minus 14 centimeter.
That experiment
shows a violation
of the electrodynamics, as
a function of the e plus,
e minus environments.
Together with
Professor Becker, we
built a spectrometer, which
has a magnet and detectors.
The detectors defined the
aperture not the magnet.
And also, two sets of Cherenkov
counters, separated by magnets,
so they're not counting the
electrons from the first one--
does not enter the second one.
And also, the electron
are measured twice, once
with the shower and the
other time with the Cherenkov
counter.
This is a picture of this
first spectrometer we made.
And this person
is Stewart Smith,
who is now the head of the
physics department at Princeton
University.
The measurement from us shows
we had a small disagreement
with earlier measurement.
In other words, we agreed
with the prediction
of the electrodynamics,
[? except ?]
for the [? mass of ?] rho,
the [? mass ?] [? of ?] phi,
and with the deviation.
This deviation
come from the fact
the photon changes after
[? rho, ?] goes back
to a photon, goes to the
electron positron pair.
Indeed, at that time,
there were a family
of three vector mesons.
They have the same
quantum number as a photon
except it has a
mass not equal to 0,
which I will call heavy photons.
At that time, most of the
people would discuss the vector
dominance model.
And I see Bernie
Margolis is here.
He did a lot of work on this.
And one can then relate that
current with the quantities
from contribution from
rho, from omega, from phi.
In this spirit, photoproduction
of vector mesons
will be deflective in nature.
And this is an article or data
taken from Scientific American.
It shows photoproduction of
pi plus [? phi ?] minus mass
as a function of angle.
The yield peaks at
the rho and peaks
more forward at heavy nuclei,
like the classical diffraction
scattering.
Analysis of this can be carried
out in the following way.
You have a photon with
a coupling constant,
let's say gamma v squared or
4 pi, and go into the nucleus,
and go back to pi
pair or k pairs.
And so this is red,
therefore, it's
a quantity of the vector
meson nuclear cross-section,
nuclear density, and a coupling.
If you took the ratio,
the coupling disappears.
It's a measurement of the
radius and vector meson
nuclear cross-section.
The first thing we measured was
the Woods' action potential.
And I see Dave Saxon is here.
And this is a very
accurate measurement
of the Saxon-Wood potential
across all the nuclei.
And the accuracy is 1.12
plus/minus 0.02 to A
to the 1/3.
Once you have measured
that, you can also look--
a vector meson decays to a
photon, and decays to e plus, e
minus.
In which case, you have
two couplings, one,
photon goes back to meson,
with a mass of the photon,
and here, with a
mass of the rho.
And the question, therefore,
are the two coupling constants
the same?
This is the
measurement of a photon
go to e plus, e minus, photon
go to rho, goes to a photon,
goes to e plus, e minus.
Clearly, because the
final states are the same,
they have the interference.
Indeed, you see
the interference.
Interference is a measurement
of this coupling constant, also
the production phase.
The results of this
series of experiments
shows the coupling constant and
the mass of the vector meson,
from rho to e plus,
e minus, is 0.5.
And from diffraction scattering,
where the photon mass is 0,
it's also 0.5.
And furthermore, the rho,
nuclear, and cross-sections,
[? lepton ?] and nuclear
cross-section-- at that time,
there was a theory, by
[? Dahl ?] and Weisskopf--
I hope Viki still remember--
and shows they are the same.
And more important,
the coupling constant
is independent of
the photon mass.
At that time,
there was a puzzle.
And that is, there were
experiments at CEA and Cornell
to look for a rho to
the electron, omega
to the electron, a
diffraction pattern.
And this pattern was looked for
a long time but never observed.
It is difficult, because
the branching region
was very small, and, therefore,
you need a high rejection.
And furthermore, the width
of omega is only 10 MeV.
Therefore, you need a
very good spectrometer.
And a new spectrometer
was built.
And from this, one
indeed observes, e plus,
e minus mass spectrum, it's
not only rho, but a sharp peak
from rho-omega interference.
You can look the vector meson
photon analogy once more.
And notice, rho goes to 2 pi.
Omega goes to 3 pi, therefore,
they do not interfere.
But omega can go to a photon.
Photon can go to a rho.
Rho go to 2 pi.
And therefore, there must
be an omega go to 2 pi.
And this, indeed,
that was looked.
And I think, at that time, the
most famous upper limit was set
by Jack Steinberger
and Günther Lütjens.
And we have looked.
Indeed, with a
good spectrometer,
if we do it very
precisely, you see,
on hydrogen and carbon
and lead, the red spectrum
is where the rho are long.
The points and the blue lines
are rho-omega interference
due to pi.
A difficult measurement
was carried out on phi
to the electron pair, because
the rate was very low.
And it obtained a
phi coupling constant
and also phi nuclear
and cross-section agrees
with the quark model.
This series of experiments
can be summarized
in the following way.
At that time, the
so-called Weinberg's
"First Sum Rule," which is
the partial width of rho,
partial width of omega,
partial width of phi
must have a triangular relation.
And this is the phi
measurement, omega measurement,
and the red line's
the rho measurement.
Indeed, the measurement agrees
with the Weinberg sum rule.
So to summarize,
the early data work
shows the decay of vector
mesons comes SU3 theory.
The electron radius is less than
10 to the minus 14 centimeter.
And the question is, are
there any more vector
mesons at a higher mass?
I should mention,
at that time, there
are many young physicists
working with us,
Joseph Asbury, who is now
the associate director
of the Argonne, Professor
Min Chen, Professor Becker,
Wit Busza, Professor Smith
at Princeton, and so forth.
And there's Sadrozinski,
Garry Sanders, and Sau-Lan Wu,
and also Robin Marshall, who
just received a distinguished
chair in Manchester.
It's also interesting to report
that the early measurement, was
confirmed by e plus
and minus collider.
And for reasons I
never understood,
the collider result
was not better
than the earlier measurement
by Becker and Chen and others.
Now we know photon and heavy
photon are almost the same.
And they do transform
into each other.
And we also learned how to
use high intensity flux, of 10
to the 11 gamma ray per
second, to obtain pi pair
rejection larger
than 10 to the a,
and to have a mass
resolution of 5 MeV.
And then the question
is, as I just said,
why should be only three heavy
photon that all has a mass 1
GeV?
And to go to higher mass,
we went to Brookhaven.
So let me now
summarize the only two
years I ever worked
in the United States,
namely, at Brookhaven.
At Brookhaven, life
is somewhat difficult.
Because from a proton
on a beryllium,
you produce many,
many particles.
The most difficult
are the electron pair,
because the radius is
1 part in 10 to the a.
That means to obtain
enough electron pair,
you need 10 to the 12 protons.
To have a pi pair
rejection of 1%,
you need a rejection of
1 part in 10 to the 10th.
This is the design
of the spectrometer.
Looks all the same,
but, actually, it's
a very difficult spectrometer.
This is looking from the top.
You have three magnets,
two Cherenkov counter
measures the electrons.
And these detectors measure
the coordinates and measures
shower.
Bending is in the
vertical plane.
The horizontal coordinate
measures theta.
Bending is a vertical plane.
And therefore, the
bending, theta and phi
are decoupled from each other.
So this is the spectrometer.
Shows the magnet,
Cherenkov counters,
and position detectors.
The target was arranged
in a helium bag.
And they are separated by 7.5
centimeter with 1.8 millimeter
beryllium.
And it's done in such a
way so that the signal
can be traced from one point.
The background, from
two different points,
can be rejected.
The magnet was measured with
a three-dimensional Hall
probe, 100,000 points.
In those days, there
were no computers.
And it was mostly done by hand.
The detector is smaller than
the magnet aperture, therefore,
the detector defined acceptance.
It's something we
learned from [? Daisy. ?]
And the magnet bends the
charged particle to an angle,
so that the detector is
never exposed to the target,
never interfered with
the neutrons and photons.
To have a rejection of
1 part in 10 to the 10,
indeed, is quite difficult. When
you have a Cherenkov counter,
if a hadron go into
a Cherenkov counter,
it knocks the electron forward.
And, therefore, the
pion will disappear.
The electron goes forward.
To reduce knock-on,
we use hydrogen gas,
which has a smaller
number of electrons.
And we put two magnets,
so that the low energy
electron does not enter the
second Cherenkov counter.
And these are very nicely
made Cherenkov counters,
with hydrogen, the very same
on both sides, including
a mirror, which is made at CERN
workshop, 3 millimeters thick.
And you see one, two,
three photoelectrons.
Position-sensitive counter
were made by Ulrich Becker.
There are 10,000 wires.
None of them broke
during the experiment.
Resolution is 1 millimeter.
The three wires are
60 degrees apart,
and, therefore, the sum
is always a constant,
and the rate is 20
megahertz, equivalent to 10
to the 36 luminosity.
And they are designed
such that output's always
a very low voltage
because of high radiation.
To have an electron, you must
have an electron detector,
and you must have a calibration.
To calibrate this, we
generate, artificially,
from proton on a target at pi
0, get a photon e plus, e minus.
[? Then ?] [? send ?] e plus
into a Cherenkov counter,
let the e minus go into
the main spectrometer.
A coincidence enables you
to calibrate your detector
on the electron,
artificial electron beam.
Because you need 10
to the 12th protons,
so you have a 10%
target, therefore,
10 to the 12th
particles are produced.
To stop photons,
electrons and muons,
we use 5 tons of uranium,
100 tons of lead.
And to stop the pion,
kaon, and so forth, we
used 10,000 tons of concrete
so generously lent to us
by Karl Strauch, from CEA.
And soft neutrons are
still left all over.
And we manage to convince Martin
Deutsch, who was the laboratory
nuclear science director,
to buy five tons of soap
to stop soft neutrons.
And this shows, if you can see
it, the location of the soap.
In fact, it's during
this experiment,
we began to know Martin Deutsch.
And he really supported us
and made an enormous effort
to make this
experiment possible.
It takes a whole week
to set up the detector,
because all of the
Cherenkov counters
must be mapped to make sure
they are 100% efficient.
All the chamber area are mapped
to make sure they're 100%.
All counter efficiency
and timing are checked.
And [? both ?] side
on all shower counters
are calibrated with
artificial electron beam.
All voltage are checked
every 30 minutes.
All magnets are
reversed once a day,
mainly because you want the
rejection of 1 part in 10
to the 10th, a mass
resolution of 1 part in 1,000.
It was also during this time, we
began to know Herman Feshbach.
And, since that was the first
experiment we are inside US,
we had then close interaction
with the Laboratory Nuclear
Science and, particularly,
Dr. Fred Eppling.
And I have benefited enormously
from these three gentlemen.
So this is the result
of this experiment.
It shows a proton
on a beryllium,
as a function of e plus,
[? give us ?] [INAUDIBLE] mass.
Indeed, show a sharp peak,
which we call the J particle.
The physicists in
this experiment,
there's Becker,
Burger, Wit Burza
helped to make sure the
proposal get approved,
Min Chen, Sau-Lan Wu, and then
Jean-Jacques Aubert, who is now
a professor in
Marseilles, Walter Toki,
a student of Becker's, now
a professor at Colorado.
And there's a nice picture.
This is Sau-Lan Wu.
This is my wife, Susan.
And there's Jean-Jacques
Aubert and Walter Toki.
Very young at that time.
After that, to look for
higher mass particle,
we did an experiment
at CERN ISR.
And essentially, it was a
proton-proton collision.
It goes to a photon, goes
to a mu plus, mu minus.
Going to look for a new
quark and look for Q Q bar
distributions.
ISR is a new concept.
Rings of protons and protons
collide, and, therefore,
the center mass is
equal to the laboratory.
It's a new type of
accelerator made
possible through the
personal, strong push
by Victor Weisskopf, when
he was director general.
This is the ISR
experiment, where you
have a proton-proton collision.
These are magnetized ions from
the [INAUDIBLE] cyclotron.
And these are very large
propulsion chambers
developed by Ulrich Becker.
And this the first time we
will enter into very large,
solid [? angle ?] devices.
I guess you can't see it.
But we have to really take
the accelerator apart in order
to install this detector.
And also, ever
since that time, we
have had a very
pleasant collaboration
with Karl Strauch and his group.
And there's the installation
of the experiment.
And it shows Ulrich Becker--
How much younger then.
And also, this is a
picture of Professor Min
Chen under the detector.
And this is the large chamber
developed by Ulrich Becker.
And it really made the
subsequent experiment possible.
The process of collisions is
known as Drell-Yan process.
So the first result
is to provide
a very accurate check
of PP interaction
in a time-like region.
And this is a direct
comparison of scaling phenomena
at s equal to 62, s
equal to 44, and shows,
indeed, the scaling
phenomena is correct.
But also, the second thing is
to see the effect of gluons.
The first effect one can
see is the following, where
you have a PP, one goes to
a photon, go to mu plus,
mu minus.
The other goes to a gluon.
If there's a gluon emission,
as a function of energy,
the transfers of momentum,
or PT, will be increased.
Indeed, this is the
PT measured from us,
and this is a measurement by
Lederman group at Fermilab,
and shows it fits to
the QCD prediction.
The second QCD effect also
concerning multiplicity.
If you look at gluon emission,
which is opposite to the mu
pairs, [? a local ?]
[? transfers ?] [? movement ?]
of mu pairs in the
opposite direction,
from where the gluon
energy increases,
because of balance of momentum,
and the multiplicity increases.
There were many young
physicists working
at ICR, Jim Branson, who is
now a professor at University
of California,
Francois Vannucci,
in Paris V, [? Soji ?]
Sugimoto in Kyoto,
Roberta Battiston, in Perugia,
and Pierre Spillantini now
is a professor in Florence.
After that, we
faced the question,
where shall we go for
the next experiment,
going to PETRA or PEP?
I want to show this
check, which I received
from Victor Weisskopf, one
of our [? author. ?] It says,
lost bet as to who is
first, PETRA or PEP.
Viki, I still have this check.
WEISSKOPF: You didn't cash it?
TING: No.
AUDIENCE: [INAUDIBLE].
TING: No.
At PETRA, you have a 24 GeV
e plus or 24 GeV e minus.
It Goes to a photon, then goes
to quarks, and the electron.
PETRA is accelerator which has
four places, TASSO, Mark-J,
Jade, and Pluto and
Cella, four detectors.
The Mark-J detector is
a very simple detector.
Basically, it's a colorimeter,
a [? four-by ?] colorimeter.
It measures hadrons, measures
muons, measures the electrons
and photons.
So this is the Mark-J detector
and shows the large chambers
made by Becker
and collaborators.
Image resolution is about
25% and covers about 95%
of the total energy.
During Mark-J, we had the first
group of Chinese ever sent
to the West.
And I went to see
Mr. Deng Xiaoping.
He said, how about training
some Chinese physicists for us?
And I asked, how many?
He said how about 100?
And I had to explain to him,
no, physicists are not soldiers.
And you have to select them.
And so he selected 10.
And now, the new director of
the Institute of High Energy
Physics and also the one in
charge of the Beijing detector,
in fact, most of the active
high energy physicists
come from this team.
Also, in 1981, Spain decided
to rejoin High Energy Physics
group and selected,
in a national way,
a group of physicists to
start working with us.
Juan Antonino Rubio
now is in charge
of the tau/charm factory.
Bernardo Adeva is a
professor in San Diego.
Martinez is a
professor in Barcelona.
Most of them have
returned to Spain
and become very,
very active there.
One of the things we
learned is measuring e plus,
e minus to mu-mu and
tau-tau, check of QED,
in the time-like region.
In the space-like
region, this e plus, e
minus goes to e plus, e minus.
And it's 1/s, and, therefore,
you take out a propagator.
A 30 GeV, 20 GeV, 10 GeV shows
a perfect agreement with QED,
taking into account the
[? re-data ?] corrections,
of course.
From this, you see the radius
of the electron and mu and tau
are less than 10 to the
minus 14 centimeters.
And one of the
important things was
done by Greg Herten
and Harvey Newman.
Harvey Newman was educated by
Lou Osborne, as you have heard.
Gregor Herten and Min
Chen also worked on this.
And that was first
reported by Harvey Newman
in the photon conference
in Fermilab in August.
And the basic idea
is very simple.
You have e plus, e minus go to
anti-quark, quark, and gluon.
Eventually, you see
three lobes of jets.
The three loop of
jet has no meaning.
You always will see that.
The important thing is the
rate must agree with QCD
and the shape must
agree with QCD.
There was a paper published
[? rather ?] [? rapidly ?]
in September, 1979.
Let me define.
In the production plane, since
the event has to be a planar,
you have a q, gluon, q bar.
And following the
terminology of Howard Georgi,
you project the momentum in
this axis, which we'll would
call major, along the thrust
axis, we'll call thrust.
In the production plane,
the events must be circular,
and your core minor.
And therefore, major minus minor
is a flatness or oblateness.
Oblateness essentially
transfers momentum of the gluon.
And therefore, it
must be essentially
0 for jet events, in which
case, major equal to minor,
the event will be circular.
And based on 500 events,
you see the rate indeed
agrees with QCD.
And without QCD,
just a quark model,
no matter what you
change the parameter,
you're not going
to fit this data.
And this is in the
production plane.
Perpendicular to the
production plane,
the shape also agrees with QCD.
That the shape agrees with
QCD is very important,
because there are many models
essentially produce three jets.
And these are the data.
And this is the QCD.
This is the phase
space distribution.
And this is Q Q
bar distribution.
Phase space, of course, also
produces three jet patterns.
Indeed, with the increasing
of oblateness or the transfers
of momentum of gluon,
you can see, gradually,
with increasing, you begin
to see the gluon jet.
When the transfers of momentum
to gluon is very small,
you have no fragmentation.
And gradually, you
have a small jet.
Eventually, you have
a full three jet.
I mention this, because you will
always see three jet events.
And this is a three jet event.
And this is a flat
event at 12 GeV.
But this event can be completely
explained by a Q Q bar
model without gluons.
Indeed, before we
publish our result,
there was an early
result by TASSO,
by Paul Soeding,
which says they indeed
find five [? flat ?] event,
where the QCD predict nine.
And they said, if the
theory is correct,
we must soon confirm this
result with higher statistics
and with much more
improved evidence.
And there's a article
by Gloria Lubkin--
I saw her.
I see her here--
describing the support
of QCD and gluons.
And this is the
data from Mark-J.
And there, it said
fairly clearly.
With time, people tend to
forget who discovered what.
And fortunately, at
that time, Mr. Schopper
was the director general.
He got hold of
everybody, together,
and agreed to say that--
Schopper told us
that Mark-J group
was the first to report
statistically significant
evidence of the three jet
pattern predicted QCD.
After sometime, people
tend to forget that.
But today, of course,
things are very different.
With higher energy,
these are the data
Professor Becker
reported this morning.
With high energy, the jet
are much more collimated.
And you can see the jets
become much narrower.
A good experiment, in fact,
also a very difficult one,
was the electroweak effect
from the existence of z0.
Because of the existence of z0,
the forward-backward asymmetry
is a function of
[? ga. ?] At this energy,
it's about minus 10%, if we
define theta as mu minus, which
is back to e minus.
If you want to look
for 10% effect,
your systematic error
has to be better than 1%.
Because of that, the
Mark-J detector actually
can be rotated, both
in phi direction
and also in theta
direction, to cancel
all the systematic effects.
The experiment e plus,
e minus to mu plus,
mu minus was the thesis of
Jean-Pierre Revol, who's
here, and also Gregor Herten.
And this is the measurement of
e plus, e minus, two mu plus, mu
minus.
This was one year before the
discovery of the Z and W.
First, you have to make
sure your detector has
no asymmetry from cosmic rays,
and, also, the low energy data
must only be explained by QED.
And then high energy cannot
be explained by QED and agrees
with the model of Glashow,
Weinberg, and so on.
And that also was
reported in Physics Today
and shows the curve which
I just presented to you.
Indeed, we were able to manage
to measure the asymmetry
as a function of energy.
Of course, over a very
limited energy region,
but, nevertheless, it agrees
with the standard model.
And I think this was originally
the work of Min Chen.
With this very crude data,
we were able to set a range
of [? GeV ?] and [? ga ?]
Together with the neutrino
data, we said the [? GeV ?]
[? ga ?] range in this region.
Today, Ulrich Becker's
data shows, now, we're
in this point.
Much work was carried out
on the physics of gluons.
One of them is a determinant of
the strong coupling constant.
Strong coupling
constant, essentially,
is the rate of three jet versus
two jet, because, in this case,
you just measure this coupling.
The first order of the strong
coupling constant is 0.2.
To complete second
order, you have
to take into account not only
the standard QED graph but also
the three gluon vertex.
When you properly take it into
account, all the second order
diagrams, your data completely
agrees with QCD prediction.
This was work mostly done by
Min Chen and Harvey Newman.
And this is really
very difficult work.
Let me just give you a feeling
what kind of systematic error
that's involved.
Using different fragmentation
models, different detector
parameters, gluon fragmentation
function, cut-off energy
transfers momentum in
the Feynman field model
or in the string model, And the
change is in the 0.01 level.
And this is the
difference in the change
of the strong coupling
constant as a function
of the cut-off in the energy
in the [? particle ?] level.
And again, it was a
difficult experiment.
There's always disagreement.
What is plotted in here?
This curve comes from
Professor Min Chen, I believe,
originally.
It's alpha s as
function of years.
And this is the measurement
by Min Chen and Newman.
And these are the
measurement by other groups.
At the beginning, they were
factor of two different.
Unfortunately, after
'86, now everybody
agree with each other.
Let's say, with him.
We also look for new quarks.
And new quarks can be
looked by the so-called R. R
is e plus, e minus to hadron
versus e plus, e minus to mu.
And they essentially
measure quark charge.
With different particles,
you see sharp peaks,
and you'll see a shoulder.
Those days, we know
the first three
quarks has a mass of
1 GeV, fourth quark
has a mass of 3 GeV.
The fifth quark has
a mass of 9 GeV.
And there was a paper
by Glashow at that time.
And it says the sixth quark,
when you take into account QCD,
must be a 38 GeV.
It's in the Physical
Review Letters.
And this is our
measurement of R.
And since we have
managed to go to 46 GeV,
and you really see
nothing at all.
When you take all the data
into account of the electroweak
effect and QCD
corrections, and then you
can set the size of the quark.
And the size of the quark
will be less than 10
to the minus 16 centimeters.
We also look for
many new particles.
And none, clearly, was found.
There were many young
physicists working with us
at that time, Albrecht Boehm,
HS Chen, Mr. Zhang, who is now
the new director in Beijing.
Peter Duinker is a professor
at University of Amsterdam.
Herten is at MIT.
Jean-Pierre Revol
and Wyslouch is also
assistant professor here.
This is a picture of the
very small Mark-J group.
And there's Harvey Newman.
Let me see.
There's Mr. Zhang, who
is the new director.
This is Peter Duinker.
This is Min Chen.
This is my wife, Susan.
There's Ulrich Becker
and Jean-Pierre Revol.
Everybody was younger then.
This morning, Ulrich
Becker mentioned the effort
at the lab, at the 27 GeV
e plus, e minus collider.
And there, we mentioned
we have a L3 experiment.
In the L3, there are
many, many physicists.
Somewhat unfortunate,
so many people,
not only from the United
States, from Bulgaria,
from China, France, Germany,
Holland, Hungary, India, Italy,
Korea, Russia, Spain,
Switzerland, and Taiwan.
There are about 120 physicists
from 16 US institutions.
And this is during one
of the group meetings,
during the assembly
of the experiment.
And this is with one
third of the physicists.
And I should mention, during
this time, Robert Birgeneau,
who was the head
of the department
and, also, at the
beginning, Jerry Friedman,
who was the director of the
Laboratory of Nuclear Science,
were most supportive to get
this experiment underway.
These are really very
difficult things.
And particularly,
Arthur Kerman really
spent a rather large
amount of effort
to support this experiment.
And this is a picture
of Arthur Kerman
with Tom Cabot during one of
the visits to L3 experiment.
And two years ago, I
think, the MIT Corporation
made the executive committee
of the MIT Corporation
come to visit L3.
And this is during
one of the receptions.
The experiment, now, had become
rather large and somewhat
complicated for L3.
For example, in
the last 18 months,
60 papers are being
written or being
published by 150 physicists.
And that means, it's really no
longer possible for a person
to really understand
everything in detail.
Certainly not me.
And Ulrich Becker mentioned
some of the major results,
a number of neutrino species,
a radius of leptons and quarks,
the mass of Higgs, Z parameter,
and precision determined
the heavy quarks,
measurement of quark mixing,
a measurement of s.
And because this is a
very precise detector,
you can measure
transaction metrics.
There are many different ways
to measure sine square W. All
agree with each other.
A model independent
measured the number
of neutrinos in the universe,
lepton flavor violation,
flavor independent of alpha s, e
plus, e minus go to Z plus eta.
This has been a very
difficult thing.
Because, in the past,
nobody's [? state ?]
has agreed with them on
the color or with QCD.
And this is the first
time we've managed
to see this is really
an experimental effect
that previous results
do not agree with QCD.
We obtained the branching
ratio and also studied hard
photon emission, J
production, and the mass
of excited electron is
larger than 122 GeV.
Mr. Becker also mentioned, maybe
someone will go to LEP 200.
One of the first thing we can
see, look for will be Higgs.
Indeed, we have now
a very large effort
to ask LEP to go as
high energy as one can.
If you go 120 GeV, you
can set the mass of Higgs
already to 100.
If the machine's 220 GeV,
you can set the mass of Higgs
to 120 GeV.
The second thing, it's a very
precise test of the electroweak
theory, the comparisons
for W from 100 and LEP 200.
LEP 100, with a field 10 to
the 6th or 10 to the 7th event,
you can measure the
mass of the Z to 15 MeV.
Measure the parameters,
various parameters
enable you to determine sines
for W to 2 plus/minus 0.005.
And LEP 200 measures e plus,
e minus to W pair by measuring
the mass of W to 50 MeV.
Since sine squared W is 1
minus mw divided by the mz,
you determine sine
square W to 0.003.
This number must agree
with this number.
The third thing if gauge
cancellation, which
Ulrich Becker also mentioned.
And that is the three diagrams
must cancel each other,
so the cross-section
is constant.
And that is most
sensitively measured
by measuring the
forward-backward asymmetry.
And then particularly, if
there's no triple boson
coupling, the rate in
the background region
will vastly increase.
So since we come to MIT,
the first thing we have done
is to measure photon to
the electron pair test QED
to the [INAUDIBLE],, define
the radius 10 to minus 14,
measure rho, omega, phi to
e plus, e minus, check SU3.
Build a spectrometer that has a
mass resolution of 1%, hydrogen
rejection 1 part in 10 to the
8th, luminosity is about 10
to the 35.
Measurement was always done
twice, once with momentum,
another time with shower.
At Brookhaven, the detector
has a mass resolution
of 1 part in 1,000.
The rejection is 1
part in 10 to the 10th.
The luminosity is 10 to the 36.
Again, we develop
a high rate chamber
but duplicate the measurement
to obtain the high rate.
ISR is the first time
we enter into 2 pi
detector with a
very good rejection
and developed large
area chambers.
At PETRA, that's the time
we developed the 4 pi
detector for discovery
of gluon and e plus, e
minus to mu plus, mu minus.
We set the radius
10 to the minus 16.
Now we check the
electroweak theory to 1%,
through the P P bar mixings,
set the mass of Higgs.
We have a 4 pi detector that
measures e, mu, gamma to 1%.
For the future, as Gregor
Herten had mentioned,
we will stay till '94
of '95 at LEP 100,
field 10 to the 6th
or 10 to the 7th.
For three to four years, maybe
five, to W pair, at which time,
there are basically
quite a few choices.
One choice, no LHC, in
which case, the machine
will go to 36 [INAUDIBLE] and
36 [INAUDIBLE],, both at W and Z,
and with a luminosity
larger than 10 to the 36.
Another possibility,
in fact, indeed,
may rightly [? happen ?] you for
new discovery coming [? HERA ?]
and to do EP.
Another is the phase
one, phase two of LEP,
with Gregor Herten mentioned.
Let me just make
a comment of EP.
In this century
since Rutherford,
since Hofstadter, and
Kendall, Friedman, Taylor,
much work, much discovery
has been made from EP.
At LHC, with 0.06 TeV
electron, with 8 TeV proton,
with a luminosity 10 to
the 32, since the electron
is stationary, and, therefore,
the electron goes everywhere,
and with the low
luminosity, basically, you
do not need to make
any modification of L3,
but, with the adding of a
forward detector, measure
protons.
Compared to HERA, the center
mass energy is factor 20 high.
And we have also looked
into what the detector will
look like for EP.
Essentially, the
BGO, vertex chamber,
has calorimeter muon chamber.
It can be kept the same,
except, in the forward part,
for the proton, we add
a proton calorimeter.
Gregor mentioned,
if you go to LHC,
there's a very simple design
by adding six Tesla coil
and putting colorimeter
and vertex chamber.
In this way, because you
have six Tesla coil, what
will happen is you will trap
all the mu, low energy particle,
and let them go
forward and backward.
Only muons go out
into your detector.
Another design is to measure
the electrons and photons very
precisely by putting
crystals very, very far away
from the vertex.
The basic idea is very simple.
At a distance of 3 meters,
a 25 GeV pi 0 go to 2 gamma.
The 2 gamma will be in
2 different crystals,
and, therefore, you
can reject the pi 0.
Well, I should mention, since
there are many detectors now,
we will proceed for L3
detector upgrade at PP or eP,
only if we have a unique
design, with unique resolution,
unique design concept, not
to the other general purpose
detectors, and,
also, a minimum cost.
If we cannot achieve that, we
probably will not proceed with
this.
And we will do something else.
I must mention that much of the
result from our collaboration
comes from doing instrumentation
development, which
is something Viki always
think is very, very important.
I totally agree with him.
And all done by Ulrich
Becker and collaborators.
Since '74, developed the high
rate chambers, '76, large drift
chamber, '79, drift tubes,
now know as straw tubes,
originally developed by him.
In '82, he developed the L3
multisampling drift chambers.
And now he has a
continuing effort for R&D.
Now, finally, let me make
a few small comments.
From my personal experience,
when I first come to MIT,
the group only had four people.
Now there are 600.
In fact, when I first come
to MIT, none of the research
really was funded
by DOE, at all.
Under the funding, we were
talking about 10 to the 4.
Now, it's 10 to the 8.
And the detectors come
from a few coincidence
to half a million channels.
Indeed, if you look, a number of
physicists collaborate with me.
And since I come to MIT,
really, unfortunately, it
has gone up so enormously.
AUDIENCE: [INAUDIBLE]
TING: Not the [? right ?]
population, no.
Clearly, this cannot have
been possible without a strong
support of the Department of
Energy and Bill Wallenmeyer,
who is here, Bernie Hildebrand,
Bill Hess, John O'Fallon, PK,
and Enloe Ritter.
I have a nice picture of Bill
Wallenmeyer, PK Williams.
Had a conversation with
my good friend Okun.
He was doing one of
the visits of L3.
But unfortunately for
us, after this visit,
he decided to take $1
million out of our budget.
It was probably because we
served the wrong coffee.
And I also wanted to
take this opportunity
to thank the MIT administration
and also the Dean of Sciences,
as well as the MIT Physics
Department, Vicki, Herman,
Francis, Jerry Friedman,
R. Birgeneau, Ernie
Moniz, and also
Peter Demos, Arthur,
Fred Eppling, and the
staff of Laboratory Nuclear
Science, particularly most
of the nonscientific staff.
Because for them,
it's not for us.
We do things for fun.
And L3 has become very
internationally visible.
And this is a visit to
L3 by the US Congress
Committee on Science
and Technology,
just the Foreign International
Collaboration Subcommittee.
Anyway, they come
with their own jet.
Finally, let me
mention, in 28 years,
the most rewarding thing
I had was to win $40.
My first $10 was October '65.
I bet with Leon
Lederman on how long
it would take to complete
the QED experiment.
And the second was
August '74, bet
with $10 with Mel
Schwartz on J particle.
And the third was $20 from Viki.
Thank you very much.
[APPLAUSE]
