On the Nature of the `Quasiparticle' Peak in the Angular Resolved   Spectrum of the Superconducting Underdoped Bi$_2$Sr$_2$CaCu$_2$O$_8$
  We study the reconfiguration of the angular resolved photoemission spectrum near $M$ point which occurs in Bi$_2$Sr$_2$CaCu$_2$O$_8$ upon cooling below the superconducting transition temperature. Restricting our attention to the case of underdoped samples we offer a phenomenological mechanism-independent argument which explains the emergence of a peak in the spectrum in terms of the normal state pseudogap. All of the basic experimental observations, including the peak dispersion, `dip-and-hump' shape of the superconducting state spectrum and appearance of the peak at the temperatures somewhat higher than $T_c$, are naturally explained. 
A.V. Rozhkov (Rutgers University)