\def \tv {{\sl tev\_2000}} \def \et {E_{\rm T}} \def \upar {\rm u_{parallel}} \def \pt {{\rm P}_{\rm T}} \def \mt {{\rm M}_{\rm T}} \def \met {\not\!\et} \def \D0 {${\rm D{\not\!{\rm O}}}$} \def \metxy {{\not\!\et}^{x,y}} \def \metx {{\not\!\et}^x} \def \mety {{\not\!\et}^y} \def \ptw {{\rm p}_{\rm T}^{\rm W}} \def \sumet {\Sigma |\vec{E_{\rm T}|}} \def \mumu {\mu^+\mu^-} \def \munu {\mu\nu} \def \Wev {W \rightarrow e\nu} \def \Zee {Z^\circ \rightarrow e^+e^-} \def \Wuv {W \rightarrow \munu} \def \Zuu {Z^\circ \rightarrow \mu^+ \mu^-} \def \Wlv {W \rightarrow l\nu} \def \Zll {Z^\circ \rightarrow l^+l^-} \def \Wtv {W \rightarrow \tau\nu} \def \Ztt {Z^\circ \rightarrow \tau\tau} \def \dnde { dN / d \eta } % \def \ppbar {p~\bar{p}} % \def \bbbar {b~\bar{b}} % \def \ttbar {t~\bar{t}} \def \qbar {\bar{q}} \newcommand{\bbar} { \bar{{\rm b}} } \def \ee {e^+ e^-} % the stuff below defines \eqalign and \eqalignno in such a % way that they will run on Latex \newskip\humongous \humongous=0pt plus 1000pt minus 1000pt \def\caja{\mathsurround=0pt} \def\eqalign#1{\,\vcenter{\openup1\jot \caja \ialign{\strut \hfil$\displaystyle{##}$&$ \displaystyle{{}##}$\hfil\crcr#1\crcr}}\,} \newif\ifdtup \def\panorama{\global\dtuptrue \openup1\jot \caja \everycr{\noalign{\ifdtup \global\dtupfalse \vskip-\lineskiplimit \vskip\normallineskiplimit \else \penalty\interdisplaylinepenalty \fi}}} \def\eqalignno#1{\panorama \tabskip=\humongous \halign to\displaywidth{\hfil$\displaystyle{##}$ \tabskip=0pt&$\displaystyle{{}##}$\hfil \tabskip=\humongous&\llap{$##$}\tabskip=0pt \crcr#1\crcr}} % The oldref and fig macros are for formatting % references and figure lists at the end of the paper. % If you type \oldref{1}Dirac, P.A.M. you will get % [1] Dirac, P.A.M. % Same goes for \fig except you get Figure 2.1 \def\oldrefledge{\hangindent3\parindent} \def\oldreffmt#1{\rlap{[#1]} \hbox to 2\parindent{}} \def\oldref#1{\par\noindent\oldrefledge \oldreffmt{#1} \ignorespaces} \def\figledge{\hangindent=1.25in} \def\figfmt#1{\rlap{Figure {#1}} \hbox to 1in{}} \def\fig#1{\par\noindent\figledge \figfmt{#1} \ignorespaces} % % This defines et al., i.e., e.g., cf., etc. \def\ie{\hbox{\it i.e.}{}} \def\etc{\hbox{\it etc.}{}} \def\eg{\hbox{\it e.g.}{}} \def\cf{\hbox{\it cf.}{}} % \def\etal{\hbox{\it et al.}} \def\dash{\hbox{---}} % common physics symbols \def\tr{\mathop{\rm tr}} \def\Tr{\mathop{\rm Tr}} \def\Im{\mathop{\rm Im}} \def\Re{\mathop{\rm Re}} \def\bR{\mathop{\bf R}{}} \def\bC{\mathop{\bf C}{}} %\def\Lie{\mathop{\cal L}} % fancy L for the Lie derivative \def\partder#1#2{{\partial #1\over\partial #2}} \def\secder#1#2#3{{\partial^2 #1\over\partial #2 \partial #3}} \def\bra#1{\left\langle #1\right|} \def\ket#1{\left| #1\right\rangle} \def\VEV#1{\left\langle #1\right\rangle} \def\gdot#1{\rlap{$#1$}/} \def\abs#1{\left| #1\right|} \def\pr#1{#1^\prime} \def\ltap{\raisebox{-.4ex}{\rlap{$\sim$}} \raisebox{.4ex}{$<$}} \def\gtap{\raisebox{-.4ex}{\rlap{$\sim$}} \raisebox{.4ex}{$>$}} % \contract is a differential geometry contraction sign _| \def\contract{\makebox[1.2em][c]{ \mbox{\rule{.6em}{.01truein}\rule{.01truein}{.6em}}}} \def\slash#1{#1\!\!\!/\!\,\,} \def\beq{\begin{equation}} \def\eeq{\end{equation}} \def\bea{\begin{eqnarray}} \def\eea{\end{eqnarray}} \def\half{\frac{1}{2}} \def\aeq{\eeq} \def\bq{\begin{quote}} \def\eq{\end{quote}} \def\pr{{\sl Phys. Rev.~}} \def\np{{\sl Nucl. Phys.~}} \def\pl{{\sl Phys. Letters~}} % \def\prl{{\sl Phys. Rev. Letters~}} \def \Msol {M_\odot} \def\gev{\,{\rm GeV}} \def\tev{\,{\rm TeV}} \def\eV {\,{\rm eV}} \def\Mpc{\,{\rm Mpc}} \def\pc{\,{\rm pc}} \def\half{\frac{1}{2}} %% macros to produce the symbols "less than or of order of" %% and "greater than or of order of" % \def \lta {\mathrel{\vcenter {\hbox{$<$}\nointerlineskip\hbox{$\sim$}}}} \def \gta {\mathrel{\vcenter {\hbox{$>$}\nointerlineskip\hbox{$\sim$}}}} %% a few convenient (?) abbreviations: % \def \endpage {\vfill \eject} \def \endline {\hfill \break} \def \etal {{\it et al.}\ } \relax %\documentstyle[12pt]{article} %\input{tex_dir:grafix.tex} % \newdimen\mywidth % \mywidth=\columnwidth/ % \newdimen\myheight % \myheight=\mywidth % \multiply\myheight 5 % \divide\myheight 4 % \mywidth=\myheight % \multiply\myheight 3 % \divide\myheight 5 % \topmargin -0.5in % \textheight 8.5in % \textwidth 6.5in % \oddsidemargin 0.0in % \evensidemargin 0.0in %\textwidth 5.9in %\textheight 9.8in %\topmargin -1.1in % \parindent 0.6in % \def\baselinestretch{1.0} % % \begin{flushright} % Version 1.0\\ % \today % \end{flushright} %%%\begin{document} % Created on 8-JUN-1995 by Chip Brock %------------------------------------------------------------------- \setcounter{page}{2} \pagenumbering{arabic} \setcounter{chapter}{0} \chapter{Foreword} {\sl In particle physics, the ``High Energy Frontier" defines, at any time, a set of problems of great theoretical interest and a set of future facilities of grand reach and scope. Meanwhile, the hands--on reality of High Energy Physics proceeds in the facilities of the present, with all of the unexpected twists and turns of scientific progress. The recent observation of the massive top quark at the Fermilab Tevatron reminds us that discovery and opportunity don't mark time, and that a vital experimental program should be prepared to respond to matters arising. Although there are, as always, new facilities in our future, that future is not so immediate, and we now have the opportunity to evaluate an unexpectedly rich new physics program at the Fermilab Tevatron, an existing facility with proven capability... }\\ \rule{6.5in}{1mm} \\ \\ \noindent This document is the report of a working group established to evaluate the potential of an extended high $p_T$ physics program at the Tevatron Collider. We have found that, in addition to a complete program of top quark physics, there is an rich catalog of topical measurements and important discovery potential in many areas. Much of this Tevatron physics potential, such as the top quark program, and significant sensitivity to light Higgs and low energy SUSY, has not been carefully evaluated until now. The report is organized as follows. This {\bf Foreword} describes the process which led to our organization and guided our work. A second chapter titled {\bf Physics Conclusions and Recommendations} contains an ``Executive Summary" of results from each of the physics working groups plus more general recommendations on the pursuit of an extended Tevatron program. There follow seven chapters which catalog the results in each of the physics subtopics. Finally, an {\bf Afterword} contains some views of where this work figures into the broader scheme of things at Fermilab and more generally in High Energy Physics. To those interested in the detailed physics studies, the individual chapters should be important and stimulating. To those with general interests, the Foreword, Conclusions, and Afterword were written to stand alone as a readable document. \section{The Potential for Tevatron Evolution} Ideas for upgrades to the Fermilab Tevatron began to surface almost immediately after the SSC cancellation. The most fully developed ideas at this point include improvements to luminosity, and the physics thrust of this study is directed toward this prospect. Since the options and their parameters have been in flux, we briefly review them here. We note that in the running period just completed (the ``1B'' run) the peak luminosity was approximately $2\times 10^{31} \rm{cm^{-2}s^{-1}}$ with an integrated luminosity in this 18 month running period of more than $100$ pb$^{-1}$. \begin{enumerate} \item {\bf Luminosity Upgrade of up to $10^{32} \rm{cm^{-2}s^{-1}}$}. This is the classic Main Injector scenario with 36 proton and antiproton bunches, 395 ns between crossings, and 3 interactions per crossing at two collision points. Further study has led to two variations on this theme: \begin{enumerate} \item The classic scenario, but with ${\cal L} = 10^{32} ~\rm{cm^{-2}s^{-1}}$ and 99 proton and antiproton bunches, leading to 132 ns between crossings and 1 interaction per crossing with two interaction regions. Detector upgrades have been designed to be compatible with this future variation. \item An expansion of the antiproton capability which should provide even higher luminosity. The recent name for a Run II which would equal or surpass $2\times 10^{32} ~\rm{cm^{-2}s^{-1}}$ is ``TeV$\star$''. In order to reach luminosities which exceed $10^{32} ~\rm{cm^{-2}s^{-1}}$ a separate, permanent magnet storage ring of 8 GeV would be built inside the Main Injector tunnel to serve as a ``Recycler'' for unspent antiprotons. In this variation, the number of overlapping interactions would rise to 6/2 per crossing at 396/132 ns. \end{enumerate} The current plan for the beginning of the Main Injector collider run, Run II, is the ``classic" scenario. It should be noted that there are now upgrade plans for CDF and D\O ~which very recently have been directed toward $2\times 10^{32} ~\rm{cm^{-2}s^{-1}}$. \item {\bf Luminosity Upgrade to $10^{33} ~\rm{cm^{-2}s^{-1}}$.} Going beyond $10^{32} ~\rm{cm^{-2}s^{-1}}$ has become a subject of considerable interest. The Main Injector and Recycler add significant capacity to the Collider Complex, and it seems that with additional low cost accelerator improvements the $10^{33} ~\rm{cm^{-2}s^{-1}}$ level is conceivable. %There are two schools of thought on this regarding %{\sl when}\ldots %which greatly complicates life for experimenters attempting to plan for the %future: %\begin{itemize} %\item Either, luminosities in excess of $2\times 10^{32} \rm{cm^2/s}$ may be doable %within even the Run %II period, %\item or ${\cal L} \simeq 10^{33} \rm{cm^2/s}$ will in fact require considerable %effort and not occur until a subsequent running period. %\end{itemize} As with the Main Injector scenarios, there are variations. \begin{enumerate} \item Bunch crossing time of 132 ns, at $10^{33} ~\rm{cm^{-2}s^{-1}}$ which gives rise to 9 interactions per crossing with two interaction regions. \item Bunch crossing time of 19 ns, at $10^{33} ~\rm{cm^{-2}s^{-1}}$ which gives rise to 1.3 interactions per crossing with two interaction regions. \end{enumerate} \noindent This ``superluminous" Tevatron upgrade has been dubbed ``TeV33''. \end{enumerate} In addition to luminosity upgrades, other ideas being discussed for the Fermilab site include center of mass energy upgrades to 4 TeV (the ``DiTevatron''), for $p\bar{p}$ or $pp$; an ultra--high energy $pp$ or $p\bar{p}$ collider; a high energy $e^+e^-$ linear collider, polarized $p$-unpolarized $\bar{p}$ collider; and a muon collider. \section{The \tv ~Effort} The \tv ~``workshop'' was a grass--roots effort motivated by the richness of the physics at the Tevatron, the lack of an organized study of the Tevatron long range potential, and the notion that facilities planning for U.S. HEP in these times would do well to include a study of ``what we could do with what we've got". It started with a two day meeting at the University of Michigan on October 21$^{\rm st}$ and 22$^{\rm nd}$ of 1994 to form an {\it ad hoc} partnership between CDF, \D0 , and the theoretical community. More than 100 physicists attended and divided into seven working groups to begin the exploration of the physics. This ``extended workshop'' continued throughout the winter, spring, and summer of 1995 on many U.S.~campuses and at Fermilab. During this period, work within the Fermilab Accelerator Division reached the point of designing a $\bar{p}$ Recycler ring for the Main Injector project, and the high luminosity Tevatron was poised to move from a concept to an engineering design phase. We believe the physics case is now at a similar level of maturity. \\ \noindent The goals of the \tv ~effort were: \begin{itemize} \item To quantify the scientific case for high $p_{\rm T}$ and electroweak physics accessible with high luminosity at the Tevatron. \item To document this case as a foundation for further literature. \end{itemize} \noindent We have accomplished both goals with the completion of this report. The physics program that we have found is broad and has compelling programmatic components as well as significant discovery potential. \\ The subsequent chapters in this report describe in detail the first results in the following general areas: \begin{trivlist} \item[] {\bf Chapter 3: Top Physics}% \item[] {\bf Chapter 4: Intermediate Vector Bosons, $W$'s, $Z$'s, and $\gamma$'s}% \item[] {\bf Chapter 5: Light Higgs Bosons}% \item[] {\bf Chapter 6: Supersymmetry}% \item[] {\bf Chapter 7: Exotics and Searches}% \item[] {\bf Chapter 8: Physics Potential of a Polarized $p$--Unpolarized $\overline p$ Tevatron}% \item[] {\bf Chapter 9: Detector Challenges}% \end{trivlist} \noindent The physics studies all use a common set of assumptions regarding luminosity performance at the Tevatron. It was decided that we would first revisit the physics accessible in the classic Main Injector scenario, and then extrapolate to both modest and extreme improvements in the luminosity. The extrapolated scenarios would presumably come in different calendar periods, but the workshop chose to ignore the vagaries of calendar and to concentrate on the physics. The parameters of the strawman scenarios are: \begin{itemize} \item{\bf Run II} \begin{itemize} \item $p{\overline p}$ with $1{\rm TeV}\times 1{\rm TeV}$. \item ${\cal L}\leq 10^{32} ~\rm{cm^{-2}s^{-1}}$ with either 395 ns bunch spacing and 3 interactions/crossing or 132 ns bunch spacing and 1 interaction/crossing. \item $\int {\cal L}\, dt=2~{\rm fb^{-1}}$. \item Proposed CDF and D\O ~Run II upgrades. \end{itemize} \item{\bf Run II--``stretch''} \begin{itemize} \item $p{\overline p}$ with $1{\rm TeV}\times 1{\rm TeV}$. \item ${\cal L}$ increasing {\bf beyond} $10^{32} ~\rm{cm^{-2}s^{-1}}$ with either 395 ns or 132 ns bunch spacing. Interactions/crossing scale from values above. \item $\int {\cal L}\, dt\sim 10~{\rm fb^{-1}}$. \item Multiple years of running, possibly overlapping with LHC. \item Incremental CDF and D\O ~Run II upgrades, as required. \end{itemize} \item{\bf High Luminosity Running} \begin{itemize} \item $p{\overline p}$ with $1{\rm TeV}\times 1{\rm TeV}$. \item ${\cal L}=10^{33} ~\rm{cm^{-2}s^{-1}}$ with 9 interactions/crossing and 132 ns bunch spacing. \item $\int {\cal L}\, dt=100{\rm ~fb^{-1}}$. We consider this upper limit to establish the asymptotic level of statistical precision in each physics study. \item ``Reasonable'' CDF and D\O ~Run II detector extrapolations. \end{itemize} \end{itemize} \noindent We assume that it will be possible to maintain detector performance levels of the CDF and \D0 Upgrades by appropriate evolution of technologies. This allows us to use standing simulations for the physics studies. Since these simulations have been tuned to existing detectors in a well studied environment, we believe that our results have a degree of credibility beyond what is usually found in proposals of this type. We have considered detector issues in a general way in Chapter 9, and we find no ``show stoppers". In a few critical cases we have also explicitly evaluated the effect of high luminosity conditions, for instance the impact of 9 overlapping interactions on the SUSY sensitivity, and on mass resolution in the Higgs search, and we have found the effects in these cases to be small. But we readily acknowledge that such issues require more work, and we hope that this report will stimulate further inquiry. Our results on the physics potential of an extended Tevatron program are summarized in Chapter 2, and described in detail in Chapters 3 through 9. Where possible, we have compared with LEPII, NLC, and the LHC. We emphasize that this is the {\em first} look at a post--SSC Tevatron and that these results should be considered preliminary. Experience with the Collider suggests that the ultimate physics menu which would develop with tens of fb$^{-1}$ will be richer than what is indicated by this initial study. \chapter{Physics Conclusions and General Recommendations} This chapter summarizes the results from each of the working groups and draws general conclusions. The results of the workshop indicate a rich and competitive physics program for a superluminous Tevatron. \section{Conclusions of the Physics Groups} \subsection{Top Physics} A detector with high--rate capability comparable to that of the CDF or D\O ~upgrades will identify approximately 500 $b$ tagged (i.e. identified) top quark events per fb$^{-1}$ in the $\ell+$ jets mode. This is 2 to 5 times the yield in this mode for equivalent luminosity at an NLC. With integrated luminosities in excess of 10~fb$^{-1}$ it will be possible to: \begin{itemize} \item Measure a top quark mass to a precision of $2\gev/c^2$ per experiment. \item Measure the $t\overline t$ production cross section to 6\%. \item Measure the top quark branching fraction to $b$ quarks in association with $W$ with precision exceeding 2\%. \item Measure the ratio of dilepton to single lepton decay rates to better than 5\%, yielding the partial width to non-$W$ final states with a precision of 6\%. \item Probe for $t\overline t$ resonances out to masses of roughly 1 $\tev/c^2$. \item Probe the $Wtb$ couplings by measuring branching fractions to $W$ helicity states with statistical precisions of a few percent. \item Isolate electroweak single top production via t-channel $W$-gluon fusion ${\rm qg\rightarrow t\bbar q'}$ and s-channel $W^*$ production ${\rm q'\qbar \rightarrow t \bbar}$, and use these production modes to: \begin{itemize} \item Measure the cross sections to $\sim 10\%$. \item Measure the partial width $\Gamma (t\rightarrow Wb)$ to $\sim 12\%$. \item Measure the CKM matrix element $V_{tb}$ with a precision of $6\%$. \item Search for anomalous couplings and CP violation effects. \end{itemize} \item Probe for the rare decay $t\rightarrow c+\gamma$ with sensitivity of $10^{-4}$. \item Probe for the rare decay $t\rightarrow Z+c$ with sensitivity of $10^{-3}$. \end{itemize} The program of accessible top quark physics at the Tevatron is certainly larger than this list and it is not inconceivable that a 180 $\gev/c^2$ fermion may have surprises in store. This is therefore {\em not} the menu of all measurements, but instead a survey of {\it sensitivity levels} for the ultimate broad program of top physics at the Tevatron. \subsection{Intermediate Vector Boson Physics} With very large integrated luminosities at the Tevatron, the electroweak sector of the SM can be probed in great detail. Our preliminary studies arrive at the following conclusions: \begin{itemize} \item With 10~fb$^{-1}$ it should be possible to measure the mass of the $W$ boson with a precision of at least 30~MeV/c$^2$, and 20~MeV/c$^2$ may well be within reach. This is about a factor of~2 better than what one expects for LEP~II. With a precision of 20~MeV/c$^2$ (30~MeV/c$^2$) for the $W$ mass, and 2~GeV/c$^2$ for the top quark mass, the Higgs boson mass can be predicted with an uncertainty of about 40\% (50\%) of itself. This prediction may be very useful for direct Higgs searches at the Tevatron, LHC, or NLC, and comparison with the results of a direct search will constitute an essential set of tests of the SM. \item The $W$ width can be measured with an uncertainty of about 15~MeV. This is an improvement of almost one order of magnitude of the current uncertainty. At LEP~II $\Gamma_W$ can only be measured with a precision of a few hundred MeV. \item The $W$ charge asymmetry will be a very powerful tool in constraining the parton distribution functions. In many processes the error in the parton distribution functions currently constitutes a major source of uncertainty. The forward backward asymmetry, $A_{FB}$ in $Z$ boson decays provides a useful cross check on the Higgs boson mass extracted from the $W$ mass measurement. \item With 10~fb$^{-1}$, the $WWV$ and $Z\gamma V$, $V=\gamma, \, Z$, vertices can be determined with a precision of ${\cal O}(10^{-1})$ and ${\cal O}(10^{-2} - 10^{-3})$, respectively, at the Tevatron. The expected accuracy for the $WWV$ couplings is comparable or better than that of LEP~II. However, since the methods used to extract limits on anomalous couplings at the two colliders are different, data from the Tevatron and LEP~II yield complementary information. Tevatron experiments will be able to place limits on the $Z\gamma V$ couplings which are up to a factor 100 better than those which can be achieved at LEP~II. At the LHC, with 100~fb$^{-1}$, it will be possible to place limits on anomalous $WWV$ and $Z\gamma V$ couplings which are a factor~3 to~100 better than those one can expect for the Tevatron with 10~fb$^{-1}$. \item The Tevatron offers a unique chance to search for the SM ``radiation zero'' in $W\gamma$ production, which provides an additional test of the gauge theory nature of the SM. At the LHC, due to the large $qg$ luminosity, QCD corrections obscure the dip in the photon lepton rapidity difference distribution which is caused by the radiation zero. This is not the case at Tevatron energies. Currently, the experimental results are statistically limited. With integrated luminosities of 2~fb$^{-1}$ or more, it should be possible to conclusively establish the existence of the radiation zero. \item With an integrated luminosity of 10~fb$^{-1}$, limits on the branching ratios of rare $W$ decays of ${\cal O}(10^{-5})$ to ${\cal O}(10^{-7})$ can be obtained. $W$ decays into two pseudoscalar mesons offer an opportunity to probe meson decay form factors at a very high momentum transfer where these form factors have not been tested so far. \item The Tevatron offers a unique opportunity to search for $CP$ violation in $W$ boson production and decay since it collides protons and antiprotons, i.e. the initial state is a $CP$ eigenstate. The extremely large number of $W$ boson events expected at a superluminous Tevatron will make it possible to search for small $CP$-violating contributions to $W$ boson production, at the level of ${\cal O}(10^{-3} - 10^{-4})$. \item An integrated luminosity of 10~fb$^{-1}$, will produce a sufficient number of $W\gamma\gamma$, $Z\gamma\gamma$ and $WW\gamma$ events to extract direct information on the quartic gauge boson couplings. \end{itemize} \subsection{Light Higgs Physics} A light intermediate-mass scalar in the mass region $80$ GeV/c$^2 < m_H <130 $ GeV/c$^2$ is predicted by minimal supersymmetric models, and current precision electroweak data also show a slight preference for a low mass Higgs. This study confirms recent theoretical speculation that there is a {\bf luminosity threshold for the detection of a light Standard Model Higgs boson at the Tevatron}, and suggests that this threshold varies from 5 to 25 fb$^{-1}$ as $m_H$ varies from 60 to 120 GeV/c$^2$. \begin{itemize} \item The process $q'\bar q \to WH$, with $H\to b\bar b$, is the best single mode for the detection of a light Higgs boson at the Tevatron, and leads to the luminosity thresholds stated above. The analysis relies heavily on the understanding of $b$ tagging, the ``$W$ + flavor" backgrounds, and mass fitting with jets, and is therefore a natural complement and extension of the top physics program. \item The process $\bar{p}p \to (W,Z)H$, with $H \to \tau^+\tau^-$ and $(W,Z) \to jj$, is difficult at the Tevatron due to the large $(Z\to \tau^+\tau^-)jj$ background, but may add to the overall significance of the observation. Other channels, such as $ZH$ with $Z \rightarrow \nu \bar{\nu}$ and $H\to b\bar b$, have not been investigated, and should be. A set of combined channels may have better significance than our single studied channel of WH with $H\to b\bar b$, and this should also be investigated. %Because a set of combined channels is likely to have better significance %than our single studied channel of $WH$ with $H\to b\bar b$, the luminosity %thresholds above are probably conservative, and the mass reach may be slightly %higher. \item We have studied the potential of the $W + H\to b\bar b$ measurement at the LHC, assuming equivalent detection efficiencies, etc and find that it is difficult there because of large top backgrounds. It may be that the intermediate mass region is accessible at the LHC only via the rare decay mode $H\to \gamma\gamma$. Since the branching fraction to $\gamma\gamma$ varies with the choice of SUSY parameters, the LHC cannot prove that the light Higgs boson of SUSY does not exist if it is not found there. \item The process $q'\bar q \to WH$ is complementary to the LEP II/NLC process $e^+ e^- \to ZH$, since it involves the coupling of the Higgs boson to different weak bosons. The ratio of these couplings can vary in multi-Higgs models with multiplets other than doublets (e.~g., Higgs triplets). \end{itemize} Although further study is needed, the opportunity to detect a light Higgs boson at the Fermilab Tevatron appears to be real. \subsection{Supersymmetric Physics} For the next decade, the Tevatron will continue to be the highest energy accelerator in the world. We must exploit this opportunity to not only study the top quark, but to search for the signature of one of the most tantalizing new physics theories proposed beyond the Standard Model - supersymmetry (SUSY). There are many arguments why SUSY provides an elegant extension to the Standard Model. SUSY solves the gauge hierarchy problem, unifies the SM coupling constants, provides a candidate for cold dark matter, solves the Higgs mass fine tuning problem and is naturally decoupled from Standard Model particles. The experimental consequence of these arguments for the existence of supersymmetry at the weak scale is the presence of 32 new particles in the mass range $\sim$100 to 1000 GeV/c$^2$. It is not surprising that none of these particles have been discovered yet, since most current limits from supersymmetric particle searches are below this range. With a detector similar to the upgraded D\O /CDF detectors and an integrated luminosity of order 20-25 fb$^{-1}$, the Tevatron will be able to significantly probe a large fraction of the expected SUSY mass range for the first time. It should be noted that the light Higgs ($h$) search is also an important concomitant search, since SUSY predicts it to be lighter than about 130 GeV/c$^{2}$. Using the SUSY model based on the particle spectrum of the MSSM (a SUSY partner for each SM particle with two Higgs doublets) combined with grand unification (based on supergravity) and $R$ parity, our preliminary conclusions are: \begin{itemize} \item We will be able to search for charginos with masses up to 250 GeV/c$^2$. The mass reach depends on the choice of the unknown SUSY parameters. Therefore, even though the Tevatron can find a chargino with a 250 GeV/c$^2$ mass, it cannot completely rule out all charginos below this mass. \item We will be sensitive to gluinos with masses up to about 400 GeV/c$^2$, depending on the SUSY parameters. Note, that the Tevatron can find gluinos with masses below about 300 GeV/c$^2$ for any choice of parameter. \item The Tevatron can search for light supersymmetric top quarks in various decay modes up to about 180 GeV/c$^2$ mass. \item The SUSY searches at TeV33 are complementary to those at LEP-II and NLC. For example, if LEP-II found a 90-GeV chargino, we expect the gluino mass to be in the range 270-360 GeV/c$^2$, which will be accesible at TeV33 (but not LEP-II). A preliminary study on the determination of the gluino mass at TeV33 shows that a 300-GeV/c$^2$ gluino mass could be measured with a resolution of about 20 GeV/c$^2$. TeV33 is also competitive to NLC in the gluino/squark searches. \end{itemize} The Tevatron enjoys an unique window of opportunity to discover the first evidence for a highly motivated theory beyond the Standard Model. The increased luminosity available at TeV33 is necessary to exploit this opportunity during the next decade. \subsection{Exotic Physics} An integrated luminosity approaching 100 fb$^{-1}$ at the Tevatron greatly extends the present mass reach for exotic objects. Specifically, a data set of 100 fb$^{-1}$ is sensitive to: \begin{itemize} \item $W'$ and $Z'$ up to $1.3\tev/c^2$ \item axigluons in dijet mode up to $1.3 \tev/c^2$ \item $E_6$ color triplet scalar diquarks in dijet mode up to $800 \gev/c^2$ \item first generation leptoquarks up to $360 \gev/c^2$ \item compositeness in $qqqq$ mode up to $2.8 \tev/c^2$ \item compositeness in $qqll$ mode up to $7.4 \tev/c^2$ \item excited quarks up to $1.2 \tev/c^2$ \item color octet $\rho_t$ in dijet mode up to $1.0 \tev/c^2$ \item massive stable particles \begin{itemize} \item color triplets up to $540 \gev/c^2$ \item color sextets and octets up to $600 \gev/c^2$ \item color decuplets up to $660 \gev/c^2$ \end{itemize} \end{itemize} Without any theoretical prejudice of the mass of new particles, a superluminous Tevatron effectively {\it doubles} the current discovery potential. \subsection{Physics with Polarized Protons} The electroweak physics benefits of polarizing the proton beam have received only a zeroth--order look. \begin{itemize} \item It may be feasible to polarize the proton beam, transversely and longitudinally in the Tevatron at high luminosity. The cost is not unreasonable, but the effect on relative performance is an issue. \item Polarizing the proton beam may result in a non--negligible improvement of the signal to noise background ratio for certain measurements, in particular where there are competing QCD and electroweak processes. \item Until a solution to the anticipated reduction in luminosity is found, the arguments in favor of polarizing one beam are not compelling enough to warrant a decision to proceed at this time. This intensity loss may not be the final story, and so it is recommended that continued accelerator R\&D be done to address this question. Likewise, the physics opportunities in this one polarized beam scenario should continue to be explored. \item If it were possible to polarize both the proton and the antiproton beams, then the above background arguments signficantly improve and distinct physics opportunities might arise. \end{itemize} \subsection{Detector Challenges} The high luminosity environment at the Tevatron will present a challenge to detectors, and more detailed work is required. Our initial impressions are as follows: \begin{itemize} \item Tracking and vertex-tagging seem to be feasible in a high--rate environment, based on current CDF experience and simulations of both the D\O ~and CDF upgrade designs. Efficiencies $> 50\%$ and mistag probability of $< 1\%$ are sufficient for the most interesting physics. Maintaining this performance in the presence of many interactions per crossing remains an issue for further study. \item Calorimeter energy resolution and coverage similar to the upgraded CDF and D\O\ detectors should be adequate. The effects of pileup on the calorimetric performance, and especially electron identification and $\met$ have been studied in a preliminary way using real minimum bias data in simple simulations. This work suggests that electron isolation efficiencies are only slightly degraded. On the matter of $\met$, we see that the degradation of primary vertex resolution may be a significant effect, but overall, for situations in which the $\met$ distribution is flat, there seems to be only a marginal effect. There are no results as yet for steeply falling distributions. \item Muon detection performance similar to the upgraded CDF and D\O\ detectors should be adequate. The muon momentum measurement will continue to be dominated by the central magnetic tracking. Backgrounds will likely become a more serious problem for muon triggering and analysis. \item Given reasonable assumptions regarding future bandwidths, a first pass at a trigger list suggests that the high $p_{\rm T}$ processes of interest can be accommodated. However, the assumptions of $50$ kHz/$5-10$ kHz/$100-200$ Hz for L1/L2/L3 outputs are aggressive goals relative to current CDF and D\O ~capabilities. The question of how the trigger rejection degrades in a high luminosity environment also needs study. \item Offline processing is always a surprise in what can be accomplished. Assuming 500 MIPS-sec per event reconstruction capability, similar to the current time, a near real--time farm would need 200 workstations of 500 MIPS each. This is not inconceivable on the timescale required. \end{itemize} \section{Recommendations} As previously noted, we believe that this work is not complete. We have shown that a future path of increasing luminosity at the Tevatron will lead to a full program of measurements in Top, IVB, Higgs, SUSY, and Exotic physics. Our general conclusions, as of December 1995, are these: \subsection{Recommendations to Fermilab} \begin{enumerate} \item Fermilab will be the top quark factory for many years. As with other heavy quarks, the top quark may be entering the first of many decades of serious scrutiny. Those planning the physics program should recognize this major scientific opportunity. \item Our study confirms recent theoretical speculation that there is a luminosity threshold for the detection of a light Higgs boson at the Tevatron, and suggests that this threshold may be at the 5-25 fb$^{-1}$ level. The most promising single detection technique relies on detailed understanding of $b$ tagging and the ``$W$ + flavor" backgrounds, and is therefore a natural complement and extension of the top physics program. We recommend that: \begin{enumerate} \item the presence of the detection threshold and its value be confirmed in more detailed simulation, including $b$ tagging in the presence of multiple interactions. \item a Tevatron strategy for crossing the luminosity threshold be developed and implemented. \end{enumerate} \item The Tevatron program can either discover SUSY or significantly constrain a large fraction of current theoretical prejudice. The actual sensitivity and discovery potential for supersymmetric states at the Tevatron deserves significantly more study. \item High instantaneous luminosity conditions need to be understood better with perhaps both simulation and actual detector research and development. This is especially true for the top and Higgs studies. Will it handicap the current detectors? If so, how? We urge the Laboratory to initiate an active program to investigate these questions and to engage the high energy physics community in the effort. We believe the effort will benefit from computing, R\&D, and possibly test beam resources. \item There may be significant luminosity capability beyond the ``classic" Main Injector scenario during Run II. If such incremental increases in peak luminosity cannot be handled by the detectors, could this capability be channeled into a significant increase in the useful longevity of $> 10^{32}$ stores? After all, {\it integrated} luminosity is the key. \item The physics overall is tantalizing, and we believe that simply waiting for the LHC is unwise. The Laboratory and the experimental collaborations should make every effort to maximize the physics return of the Tevatron. This implies the need for {\bf an overall plan for the long term Tevatron Program} including the accelerator, the detectors, and physics simulation. \end{enumerate} \subsection{Recommendations beyond Fermilab} Compared to the reach of the SSC or the LHC, the high $p_{\rm T}$ physics program at the Tevatron has sometimes been casually judged to be at an end. During the SSC era, this judgement devalued all future planning for the FNAL complex, and as the LHC era looms, this sentiment might be heard again. Meanwhile, the Tevatron has uncovered a new fermion with a mass at the weak scale, and new ideas about the Tevatron luminosity enable a compelling menu of top quark and discovery--level high $p_{\rm T}$ physics --- a complete Physics Program. This research was not even contemplated a year ago as applicable to Fermilab. A productive Fermilab facing a planned LHC is an interesting example of the tension between present and future in the age of Big Science, and the importance for balance between long range commitments and data driven progress. This issue is addressed in Chapter 10.