  Slightly underdoped high-Tc system La(1.86)Sr(0.14)CuO(4) (LSCO) is studied
by means of high energy high resolution angular resolved photoemission
spectroscopy (ARPES) and combined computational scheme LDA+DMFT+Sk.
Corresponding one band Hubbard model is solved via dynamical mean-field theory
(DMFT), while model parameters needed are obtained from first principles within
local density approximation (LDA). An "external" k-dependent self-energy Sk
describes interaction of correlated electrons with antiferromagnetic (AFM)
pseudogap fluctuations. Experimental and theoretical data clearly show
"destruction" of the LSCO Fermi surface in the vicinity of the (pi,0) point and
formation of "Fermi arcs" in the nodal directions. ARPES energy distribution
curves (EDC) as well as momentum distribution curves (MDC) demonstrate
deviation of the quasiparticle band from the Fermi level around (pi,0) point.
The same behavior of spectral functions follows from theoretical calculations
suggesting AFM origin of the pseudogap state.
