%\subsection*{Introduction}
\label{sec:B:intro}

\bigskip
\smallskip

%In this note we summarise the activity of the working group on $B$ physics
%at the scientific retreat, ``SuperB Workshop VI: New Physics at the Super
%Flavour Factory \superb\,'' held January 7-15$^{\rm th}$, 2008 at IFIC in Valencia.
%
%Throughout the text we will attempt in a coherent manner to answer the
% questions we received  from the International Review Committee.

The physics case for \superb\ has been
discussed in some detail in the \superb\ Conceptual Design Report (henceforth CDR)~\cite{Bona:2007qt}.
In the CDR, and in the following, we consider the discovery potential of \superb\
in two scenarios: whether or not the LHC finds evidence for New Physics. \\

\noindent
{\it LHC discovers new particles} \\
\par
\vskip - 9pt
\noindent
  If the LHC finds physics beyond the Standard Model, the essential, and unique, role of \superb\ will be to determine the flavor structure of the New Physics.  In that sense, measurements from \superb\ that
  are consistent with the Standard Model are as valuable as those that show
  significant deviations -- in either case these measurements provide information
  about the New Physics flavor structure that cannot be provided by other experiments.
%  In this context the goal then will no longer be to discover new physics,
%  but to measure its flavor properties.
  In this context, the measurement of  theoretically  clean rare  decays,
  even when found to be Standard Model-like, will yield valuable
  insights into the structure of New Physics models, providing
 information complementary to LHC results.

  It is, of course, generally regarded as more valuable to find deviations from Standard Model predictions than to
  find a result that agrees with the Standard Model.
  In fact,
  many New Physics flavor structures do produce measurable
  effects. As shown in the discussion on benchmark points below, there are also
  scenarios in which flavor effects can be very small, and perhaps barely visible, even
%ALTERNATIVE to ``It is, of course ... and perhaps barely visible, even'' which sounds too negative:
%  While most New Physics flavor structures do produce measurable
%  effects, there are scenarios, as shown in the discussion on benchmark points below,
%  in which flavor effects can be very small, and perhaps barely visible, even
  with \superb. The great precision reached at \superb\ can still provide positive
  information on the underlying theory, even in a Standard Model-like flavor scenario.
  Indeed, we emphasize that measurement of the New Physics flavor couplings are the primary discovery goal
  of \superb;  results from both LHC and \superb\ are required to reconstruct the New Physics Lagrangian.\\

\noindent
{\it There is no New Physics discovery at LHC} \\
\par
\vskip -9pt
\noindent
  If evidence for New Physics does not readily appear at LHC, the goal of \superb\ would
  then be to emphasize measurement precision to search for deviations in
  flavor observables.  In this scenario, finding such small effects could provide the first
  evidence of New Physics!  The absence of knowledge about the New Physics scale from LHC would
  make it impossible to reconstruct the New Physics Lagrangian, but a New Physics discovery at
  \superb\ would provide a solid indication that the New Physics scale is only slightly
  above the reach of LHC. \\

The chapter is organized as follows.
We first present a description of work done since
the writing of the CDR~\cite{Bona:2007qt}, concentrating on some particularly
interesting channels that were only partially covered or not covered at all.
We then update the phenomenological studies presented in the CDR,
including a classification of golden modes, performance at LHC benchmark points,
the impact of \superb\ on explicit models of SUSY breaking, and a brief discussion on
the interplay of flavor and high $p_{T}$ physics.
We concentrate on $B$ physics at the \FourS,
since we have little to add to previous studies of
the potential for $B_s$ physics at the \FiveS~\cite{Baracchini:2007ei}.



















































