%
%  Talk to UC SCR on 15 March 1999
%
\documentstyle[epsfig,colordvi,pagecount]{slides}

\input latex.macros
\input top.macros
\def\DZero{D$\mbox{0\kern-.55em /}$}
\def\mDZero{{\rm D}\mbox{0\kern-.55em /}}
\def\mGeVcc{{\rm GeV\, c^2}}
%

\newcommand{\tit}[1] {
        \begin{center}
        \normalsize
        \fbox{\Red{#1}} \vspace{.25in}
        \end{center}
        \small
}


\def\met{\mathbin{E\mkern - 11mu/_T}}

\begin{document}

\small

\tit{The Nature About Truth and Beauty}

\Start
\vspace{0.5in}
\begin{center}
Pekka Sinervo\\
{\it University of Toronto}
\end{center}

\vspace{0.5in}

\Red{Overview}

\tiny
\begin{itemize}
\item What is Inside a Proton?
\item Forces, Leptons and Quarks
\item Discovery of Beauty
\item Discovery of Truth
\item Whither Next?
\end{itemize}

\begin{flushright}
University College \\
15 March 1999
\end{flushright}

\pagebreak
%
%
\tit{Inside a Proton -- Some High School Physics} 
\small
Start by reviewing today's high school science
\tiny
\begin{itemize}
	\item Matter is made up of atoms
	\item There are about 109 different species!
	\item Atom itself has structure:
	\begin{itemize}
		\item consists of small hard ``core'' (nucleus)
		\begin{itemize}
			\item nucleus made of protons and neutrons
		\end{itemize}
		\item large cloud of electrons 
	\end{itemize}
	\item We can describe all atoms using 3 particle types
	\begin{enumerate}
		\item electrons ($e^-$)
		\item protons ($p$)
		\item neutrons ($n$)
		\\[0.1in]
	\end{enumerate}
\end{itemize}
\small
But there are hundreds of particles like $p$\ and $n$'s
\tiny
\begin{itemize}
	\item Leptons
	\item Hadrons
\end{itemize}
\tiny
\pagebreak
%
%  Stepping Back...
%
%
\tit{Some History About Structure}
\small
Lord Rutherford performed seminal scattering studies
\tiny
\begin{itemize}
	\item Looked at $\alpha$\ scattering off gold (1911)
	\item Consistent with Coulomb scattering off point
particle
\end{itemize}
\begin{center}
$\Rightarrow$ Uncovered the nucleus \\[0.1in]
\end{center}

\vspace*{.3in}
\small
Hofstadter and colleagues extended this work
\tiny
\begin{itemize}
	\item Studied $1$~GeV $e^-$\ scattering off nuclei (1953)
	\item Found that nucleus had extended charge distribution
\end{itemize}
\begin{center}
	$\Rightarrow$ shape of the nucleus \\[0.1in]
\end{center}

\vspace*{.3in}
\small
Taylor and colleagues probed more finely
\tiny
\begin{itemize}
	\item Used $\sim18$~GeV $e^-$\ scattering off proton (1968)
	\item Found that nucleons were extended objects
\end{itemize}
\begin{center}
	$\Rightarrow$ discovered quarks! \\[0.1in]
\end{center}

\vspace*{.3in}
\small
\pagebreak
%
%  Basics of scattering theory
%
\tit{About Rutherford Scattering}
Rutherford developed classical theory of scattering
\tiny
\begin{itemize}
	\item Charged particle $Z_1 e$\ scattering off nucleus $Ze$

\slidefig{0.5in}{1.5in}{4.5in}{../substructure_96/alpha_scattering.eps}{100.0}

	\item Define $\vec{q} = \vec{p} - \vec{p}^\prime$, so that
	$q = 2p \sin {{\theta}\over{2}} $
	\item Differential cross section is
\begin{eqnarray}
\left( {{d\sigma}\over{d\Omega}} \right)_R =
  {{4m^2 \left(Z_1 Z e^2\right)^2}\over{q^4}} \nonumber
\end{eqnarray}
	\item Correct classical and QM result 
		$\Rightarrow$\ {\it Rutherford Scattering}
\\[0.1in]
\end{itemize}
\small
Discovered what we now call the {\bf nucleus}
\tiny
\begin{itemize}
	\item To Rutherford, it looked like a point
	\item We now know it is $\sim 10^{-12}$~m in size
\end{itemize}
\pagebreak
%
%   Mott Scattering and Form Factors
%
\tit{What Happens for Extended Objects?}
When scattering particle is extended in space
\tiny
\begin{itemize}
	\item Introduce ``form factor'' $F(q^2)$
\begin{eqnarray}
F(q^2) = \int \rho(\vec{R}) e^{i\vec{q} \cdot \vec{R}} d^3\vec{R}
\nonumber
\end{eqnarray}
	\item Fourier transform of ``charge'' density $\rho$
\end{itemize}
\begin{eqnarray}
\Rightarrow \left( {{d\sigma}\over{d\Omega}} \right) =
\left( {{d\sigma}\over{d\Omega}} \right)_{\rm R} \left|
F(q^2)\right|^2
\nonumber
\end{eqnarray}
%
%  Example of Yukawa-type charge distribution
%
\slidefig{3.0in}{2.5in}{0.0in}{../substructure_96/yukawa_form_factor.eps}{100.0}

\pagebreak
%
%	DIS Results
%
\tit{Proton Structure}
Deep inelastic $e^- p$\ scattering reveals proton structure
\tiny
\begin{itemize}
	\item study inelastic part of cross section
	\begin{eqnarray}
	e^- p \rightarrow e^- X_{\rm hadrons}
	\nonumber
	\end{eqnarray}
	\begin{itemize}
		\item suppress ``coherent'' and resonant nuclear scattering 
	\item Begin to see scattering off of constituents
	\item Hitting partons with smaller $x$\ ($x$\ is 
		momentum fraction)
	\end{itemize}
	\item epitomised by ``structure functions'' $F_i(x,q^2)$
\end{itemize}

\slidefig{3.7in}{0.0in}{1.0in}{../substructure_96/f2_vs_x.eps}{70.0}
\begin{eqnarray}
\left( {{d^2\sigma}\over{d q^2 dx}} \right) \sim
{{4\pi\alpha^2}\over{q^4}} \left[ (1-y) {{F_2(x,q^2)}\over{x}} + ...
\right]
\nonumber
\end{eqnarray}

\pagebreak
%
%  Taylor, Kendall a
%
\tit{Deep Inelastic Scattering Results}
SLAC DIS studies revealed clear internal structure
\tiny
\begin{itemize}
	\item Evident as hadronic energy $W$\ increases (decreases $x$)

\end{itemize}

\slidefig{4.0in}{0.0in}{1.0in}{../substructure_96/dis_plot.eps}{120.0}

\small
Detailed studies of structure functions $F_1$\ and $F_2$\ show
\tiny
\begin{itemize}
	\item Charge 1/3 and 2/3 particles
	\item Spin 1/2 particles
	\item Presence of anti-particles (the ``sea'')
\end{itemize}

\pagebreak
%
%  Picture today
%
\tit{Bricks and Mortar in 1975} 
\small
The ``Standard Model'' of Elementary Particle Physics
\begin{itemize}
\tiny
\item Four ``generations'' of quarks and leptons
\small
\begin{center}
$\left( \begin{array}{c} u \\ d \end{array} \right)
\left( \begin{array}{c} c \\ s \end{array} \right)
\left( \begin{array}{c} Q=+2/3 \\ Q=-1/3 \end{array} \right)
% \left( \begin{array}{c} t \\ b \end{array} \right)
$
\\[0.2in]
$
\left( \begin{array}{c} e       \\ \nu_e \end{array} \right)
\left( \begin{array}{c} \mu     \\ \nu_\mu \end{array} \right)
\left( \begin{array}{c} Q=-1 \\ Q=0 \end{array} \right)
% \left( \begin{array}{c} \tau    \\ \nu_\tau \end{array} \right)
$
\\[0.2in]
\end{center}
\tiny
Come in ``pairs'' because of the way forces acted on them

\tiny
\item Forces carried by bosons
\tiny
\begin{center}
\begin{tabular}{lc}
\hline \\
Electromagnetic force 		&	$\gamma$		\\[0.1in]
Weak force 			&	$W^\pm, Z^\circ$\ bosons \\[0.1in]
Strong force 			&	eight gluons		\\[0.1in]
Gravity 			&	gravitons \\[0.1in]
\hline
\end{tabular}
\end{center}
\tiny
\item
Quark and lepton mass due to ``Higgs'' particle
\end{itemize}
\pagebreak
%
%
\tit{How this Picture Developed}
\small
Leptons appeared fundamental
\tiny
\begin{itemize}
	\item electron is the most ubiquitous
	\item other leptons can be produced and studied
	\item neutrinos are particularly  ``ephemeral''
\\[0.1in]
\end{itemize}
\small
Colour force predicts that quarks only bind when 
\tiny
\begin{itemize}
	\item three quarks (or three anti-quarks)
	\item a quark and an anti-quark
\\[0.1in]
\end{itemize}
\small
For example, a proton is made up of 3 quarks
\tiny
\begin{itemize}
	\item 2 up quarks
	\item 1 down quark
\\[0.1in]
\end{itemize}
\small
Four flavours $\Rightarrow$\ get all known
``elementary particles''
\tiny
\begin{itemize}
	\item This model works very well
\end{itemize}
\pagebreak
%
%  problems...
%
\tit{But Some Exciting Problems}
\small
In 1977, team led by Leon Lederman discovered a new particle
\tiny
\begin{itemize}
	\item Heaviest particle ever seen (about 10 proton masses)
	\item Discovered in remnants of very high energy $p-p$\ collisions
	\item Looked like a neutral meson made up of a particle and
	anti-particle
	\begin{itemize}
		\item Had to be a new, unexpected type of quark
		\item Called $b$\ quark (for either 
		``beauty'' or ``bottom'')
		\item Weighed about 5 proton masses
		\item Production rate implied $Q=-1/3\ e$
\\[0.05in]
	\end{itemize}
\end{itemize}

\small
What did this mean?
\tiny
\begin{itemize}
	\item New colliders at Cornell and Hamburg started studying
	its properties
	\item Was heavy, lived for a fairly long time (about
$10^{-12}$~s)
	\item The way electroweak force acted on it
	\begin{itemize}
		\item[$\Rightarrow$] Had to have a partner $\Rightarrow$ $t$ quark
	\end{itemize}
\end{itemize}

\pagebreak
\tit{Status of Things in 1985}
Some pieces of this puzzle were not there
\tiny
\begin{enumerate}
	\item Expected ``Unification'' of forces 
	\begin{itemize}
		\item don't have a clue as to how to understand gravity
		\item only have hints that forces are unified
	\end{itemize}
	\item Don't understand mass at all
	\begin{itemize}
		\item ``Higgs'' boson has not been seen.....
	\end{itemize}
	\item Missing the last quark \\[0.1in]
\end{enumerate}

\small
But the rest of it worked extremely well! 
\tiny
\begin{itemize}
	\item Many tests have been made over last 20 years \\[0.1in]
\end{itemize}

\small
Challenge is to get data to address these questions
\tiny
\begin{itemize}
	\item $\Rightarrow$\ Focus on the incomplete pieces
\end{itemize}
\pagebreak
%
%
\tit{Why MUST the Top Quark Exist?}
Other experiments showed that if
top doesn't exist, the theory just dies
\tiny
\begin{itemize}
\item Masses of the $W^\pm$\ and $Z^\circ$\ bosons
cannot be explained 

\vspace{1.0in}
\vbox{
\vskip+0.2in
\hskip+1.0in
\special{psfile=physics_figures/mass_loops.eps  hscale= 75.0 vscale= 75.0}
\vskip-0.2in
}

\tiny
\begin{itemize}
\item Measurements of the $Z$\ boson require
\tiny
\begin{center}
$M_{top} = 166^{+17+19}_{-19-22}$\ \GeVcc  \\[0.2in]
\end{center}
\end{itemize}

\small
\item Behaviour of the bottom quark implies that it must have a partner
\tiny
\begin{itemize}
	\item Weak force predicts asymmetry in $e^+e^-\rightarrow b\bar{b}$
\end{itemize}
\small
\item $B$\ meson ``mixing'' could not occur
\end{itemize}
\vspace{2in}
\vbox{
\vskip+0.0in
\hskip+0.0in
\special{psfile=physics_figures/b_bbar_mixing.eps  hscale= 100.0 vscale= 100.0}
\vskip-0.0in
}

\pagebreak
%
%  How Does One Find Top?  Production
%
\tit{Searching for Top}
\small
Big Bang was last time nature created top quarks
\tiny
\begin{itemize}
	\item Can now pair-produce a heavy quark with enough energy
	\item Require high energy matter-antimatter collisions 
	\item Need tons of data (they are rare events) \\[0.1in]
\end{itemize}
\vspace{1.5in}
\vbox{
\vskip+0.0in
\hskip+3.0in
\special{psfile=prd_plots/ee_collisions.ps  hscale= 75.0 vscale= 50.0}
\vskip-0.0in
}

\small
$p\bar{p}$\ Collider at Fermilab was the place to search for it
\tiny
\begin{itemize}
	\item  High luminosities 
    (${\cal L} \sim 25\times 10^{30}\ {\rm cm^{-2}s^{-1}}$)
\begin{itemize}
	\item compare to radiation in this room
    ${\cal L} \sim 2\times 10^{-2}\ {\rm cm^{-2}s^{-1}}$)
\end{itemize}
\item Highest energies ($\sqrt{s} = 1800$\ GeV) 
\begin{itemize}
	\item Enough energy to form fairly complex molecule
\end{itemize}
	\item Collected 3 million collisions
\end{itemize}

%
%  insert plot of cross section
%
\pagebreak
%
%  Discuss stability and decays
%
\tit{Why are Heavy Quarks Hard to Find?}
\small
Hard to produce
\tiny
\begin{itemize}
	\item Must sift through lots of matter-antimatter collisions
	\item Happens about 1 in every billion collisions? \\[0.1in]
\end{itemize}

\small
They Decay!
\tiny
\begin{itemize}
	\item A top quark decays via the weak force into a bottom quark
	\item The bottom quark then decays into lighter quarks \\[0.1in]
\end{itemize}
\vspace{1.0in}
\vbox{
\vskip+0.0in
\hskip+0.0in
\special{psfile=physics_figures/top_weak_decay_chain.eps  hscale= 100.0 vscale= 100.0}
\vskip-0.0in
}

\small
Ya can't see free quarks
\tiny
\begin{itemize}
	\item Quarks are ``not allowed'' to appear unescorted in public
	\item Have to ``dress'' themselves up around other quarks
	\item Result in ``jets'' of particles
\end{itemize}
\vspace{1.0in}
\vbox{
\vskip+0.0in
\hskip+2.0in
\special{psfile=physics_figures/dressed_quark.eps  hscale= 75.0 vscale= 50.0}
\vskip-0.0in
}

\pagebreak
%
%  Top Quark Decay Signatures
%
\tit{Top Quark Signatures} 
\small
Top quarks only decay via the weak force
\tiny
\begin{eqnarray}
t    &\rightarrow& W^+ b \nonumber \\
  &  & \mrightdownarrow u \bar{d}\ {\rm or}\ c \bar{s} \nonumber
\\
  &  & \mrightdownarrow e^+ \nu_e\ {\rm or}\ \mu^+
\nu_\mu\ {\rm or}\ \tau^+ \nu_\tau \nonumber
\end{eqnarray}
%
%  Plot of decay
%
\vspace{2.0in}
\vbox{
\vskip+9.8in
\hskip-2.0in
\special{psfile=prd_plots/feynman_top_decay.ps  hscale=100.0 vscale=100.0}
\vskip-9.8in
}

\small
This results in a number of very unusual ``signatures''
\tiny
\begin{itemize}
\item Can use these characteristics to sift the collisions
\end{itemize}

\pagebreak
%
%  The CDF Experiment
%
\tit{The Race for the Top}
By 1987, competition on to search for the top quark
\tiny
\begin{itemize}
	\item Joined an ``intimate'' collaboration of about 300 
	physicist
	\item Constructed the CDF detector 
\tiny
\begin{itemize}
\item Large 5000 ton detector 
\item Think of it is a very big (expensive) microscope 
\begin{itemize}
	\item Allows one to detect and measure the results of
the collisions
\\[0.2in]
\end{itemize}
\end{itemize}
\end{itemize}

\small
Collaboration now consists of
\tiny
\begin{itemize}
\item 39 institutions from US, Japan, Italy, Canada and Taiwan
\item 450 physicists
\\[0.1in]
\end{itemize}
\small
Why so many people?
\tiny
\begin{itemize}
	\item takes enormous scientific effort to mount experiment
	\item continual improvements and repairs
\end{itemize}

\pagebreak
%
%
\tit{In 1995, the Evidence was in...}
\small
In about 10 billion collisions, found about 50 events
\vbox{
\vskip+3.0in
\hskip+1.5in
\special{psfile=run1b_blessed_plots/dil_57621_45230_tracking_only.eps  
hscale= 80.0 vscale= 80.0}
\vskip 0.5in
}
\small
We observe about the right number of different kinds of events
\tiny
\begin{itemize}
	\item Observe 1 $\mu^+\mu^-$\ event and 5 $e\mu$\ events
	\item Expect $1.3\pm0.3$\ events from background 
	\item Observe $\sim 40$\ events with $W+\ge3$~jets \\[0.1in]
\end{itemize}
\tiny
\small
Probability of background looking like this is $<10^{-6}$

\pagebreak
%
%
\tit{Whats Happening Now?}

\small
Finished taking data in 1996, now completing analysis
\tiny
\begin{itemize}
	\item Now have enough top decays to measure its properties
	\begin{itemize}
		\item mass ($175\pm6$~\GeVcc)
		\item how it decays (like we expect)
		\item how it gets produced (just about right)
\\[0.05in]
	\end{itemize}
\end{itemize}

\small
Our group is now improving CDF -- ready by 2000
\tiny
\begin{itemize}
	\item Collider will start running again at $\times10$\ higher
	intensity
	\item Collect about $\time50$\ more top events
\\[0.05in]
\end{itemize}

\small
Will be using this data to
\tiny
\begin{itemize}
	\item measure properties of top and bottom quarks
	\item search for new ``physics''
\end{itemize}

\pagebreak

\tit{Where Do We Go From Here}
\small
Still at least one missing piece -- Higgs Boson
\tiny
\begin{itemize}
	\item We think it is the key for why ``mass'' exists
	\item Building a new proton-proton collider in Geneva
	\begin{itemize}
		\item Large Hadron Collider
		\item 7 times more energetic than Fermilab Tevatron
		\item 100 times higher collision rate
		\item experimental teams have over 1000 scientists
	\end{itemize}
	\item But don't hold your breath
	\begin{itemize}
		\item Turn-on scheduled for 2005!
\\[0.05in]
	\end{itemize}	
\end{itemize}	

\small
This question of Mass is really important!
\tiny
\begin{itemize}
	\item Still don't really understand what energy is
	\item Gravity remains a mystery
	\item Don't really know WHY we have the world that we do
	\begin{itemize}
		\item So why truth and beauty?
		\begin{itemize}
			\item Heaviest building blocks in nature
			\item Has to be a clue there (but what?)
		\end{itemize}
	\end{itemize}
\end{itemize}
\pagebreak
%
%
\tit{So What?} 
\small
Top quark discovery is a triumph of the Standard Model
\tiny
\begin{itemize}
	\item validates 17 years of work
	\item ends a great deal of speculation
	\item strong indication that we are on the right track 
	\begin{itemize}
		\item focus on remaining pieces of puzzle now
\\[0.1in]
	\end{itemize}
\end{itemize}
\small
We have no idea of the practical benefit this will bring
\tiny
\begin{itemize}
	\item basic research is something like Pandora's Box
	\item history has shown that basic research eventually has impact
	\begin{itemize}
		\item totally unpredictable
		\item impossible to value accurately
	\end{itemize}
\end{itemize}
\pagebreak
%
%
\tit{Why Are These Questions So Important?}
%
Humanity seems to be ``driven'' to wonder
\tiny
\begin{itemize}
	\item We seek out frontiers
	\begin{itemize}
		\item Physical challenges
		\item Intellectual challenges
	\end{itemize}
	\item Is there somethere out there we don't understand?
	\begin{itemize}
		\item science allows us to focus our questions
		\item ask what appear to be the ``best'' questions
	\end{itemize}
	\item We question where we fit in? \\[0.1in]
\end{itemize}
\small
Push our technological frontier
\tiny
\begin{itemize}
	\item This physics is the most ``basic'' of basic sciences
	\item Historically, very rich in spin-offs
	\begin{itemize}
		\item Nuclear medicine, imaging
		\item Smoke detectors and other sensors
		\item Nuclear power, weapons
		\item Large scale data processing
		\item[......] List goes on \\[0.1in]
	\end{itemize}
\end{itemize}
%
\small
Presents some of the greatest intellectural challenges
\tiny
\begin{itemize}
	\item Attracts some of our most creative and energetic people
	\item Allows one to leave a ``mark'' on our world
\end{itemize}
\pagebreak
%
%
%
\tit{Summary}
\small
Haven't reached the end of the story
\tiny
\begin{itemize}
	\item Many open questions, for example
	\begin{itemize}
		\item What and where is mass?
		\item What really are quarks? leptons? neutrinos?
		\item How did our universe become what it is today?
\\[0.1in]
	\end{itemize}
\end{itemize}
\small
But we are making progress
\tiny
\begin{itemize}
	\item We have a ``picture'' that works pretty well already
	\item Focusing on those pieces that don't quite fit
\\[0.1in]
\end{itemize}
\small
Soon we hope to have a much better understanding of
\tiny
\begin{itemize}
	\item the bricks, 
	\item the mortar, 
	\item ...and what nature builds with it.
\end{itemize}

\pagebreak
%
\small
\begin{center}
Consider Now the Quark \\[0.5in]
\end{center}

\tiny
\begin{tabbing}
Consider \= now the Quark, which is \\
 \> A Concept sub-atomical. \\
No man alive has seen its phiz; \\
 \> Perhaps it isn't Is at all. \\[0.1in]

A Concept sub-atomical \\
 \> Too tenuous I find to prove. \\
Perhaps it isn't Is at all. \\
 \> This goes for Hate, and also Love. \\[0.1in]

Too tenuous I find to prove \\
\> The Sun, the Shadow, and the Wind. \\
This goes for Hate, and also Love. \\
\> And other matters of the kind. \\[0.1in]

The Sun, the Shadow, and the Wind. \\
 \> The Dream, the Doing, the Depair, \\
And other matters of the kind \\
 \> I find are proven best in prayer. \\[0.1in]

The Dream, the Doing, the Despair, \\
 \> And other matters, being His, \\
I find are proven best in prayer. \\
 \> Consider now the Quark, which Is. 

\end{tabbing}

\begin{flushright}
{\it The Primer of Prosidy} \\
- Espy
\end{flushright}
%
\end{document}
