Dk. Srivastava et Ji. Kapusta, NATURE OF THE PHOTON-CORRELATION FUNCTION FOR QUARK-GLUON PLASMA, Physical review. C. Nuclear physics, 50(1), 1994, pp. 505-508
The correlation function for intensity interferometry of high energy p
hotons emitted from an expanding quark-gluon plasma is examined. It is
reiterated that the correlation function for identical bosons emitted
from two point sources is given by 1 + cos(DELTAk . DELTAx) and will
oscillate between 0 and 2, depending on the values of the difference i
n the 4-momenta of the two bosons (DELTAk) and the difference in their
4-positions (DELTAx). Integration over smooth, realistic sources, rel
evant for very high energy nucleus-nucleus collisions, gives a correla
tion function which essentially decreases monotonically from 2 to 1 as
the momentum difference becomes large. The oscillatory behavior seen
in a recent work for certain momentum configurations is caused by an a
pproximation which amounts to including only those sources for which t
he space-time rapidities are identical to the photon rapidities.