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Durham University

Department of Physics

Staff profile

Publication details for Prof Sir Arnold Wolfendale

Erlykin, AD & Wolfendale, AW (2004). Sling effect in AA-interactions and its implication for UHECR. Nuclear Physics B-proceedings Supplements 136: 282-289.
  • Publication type: Journal Article
  • ISSN/ISBN: 0920-5632

Author(s) from Durham


The 'Sling effect' appears when a fragment of a projectile nucleus
emitted after a peripheral collision of the latter with a target
nucleus is caused to rotate with a high spin. The spinning fragment has
a deformed shape and looks like an oblate ellipsoid. Due to the virtual
non-compressibility of nuclear matter and the polarization of the spin
in the plane transverse to the input momentum of the projectile nucleus
such an ellipsoid has a reduced mean interaction cross-section compared
with a non-spinning fragment which has a spherical shape. Due to purely
geometrical arguments, such an ellipsoidal nucleus should have
additional fluctuations of the cross-section even at the fixed impact
parameter dependent on the orientation angle between the axis of the
ellipsoid and the vector connecting centers of projectile and target
nucleus. The number of wounded nucleons in the projectile nucleus
participating in the interaction correlates strongly with the
interaction cross-section. All these reasons lead to a non-exponential
attenuation of fragments and an increased probability of finding the
fragment at a large depth in the absorber.
If the sling effect appears in the interaction of a primary cosmic ray
nucleus with nuclei in the atmosphere the induced atmospheric cascade
will have a slower attenuation, and thereby can help to reduce some
inconsistencies in the interpretation of the existing experimental data
on extensive air showers, observed in the lower half of the atmosphere.
It will also have an implication on the development of nucleus-induced
cascades at ultra high energies.