Novel corrections to the momentum sum rule for nuclear structure functions
- Resource Type
- article
- Authors
- Stanley J. Brodsky; Valery E. Lyubovitskij; Ivan Schmidt
- Source
- Physics Letters B, Vol 824, Iss , Pp 136812- (2022)
- Subject
- Deep inelastic scattering
Diffractive deep inelastic scattering
Parton distribution functions
Nuclear structure functions
Momentum sum rules
Operator expansion
Physics
QC1-999
- Language
- English
- ISSN
- 0370-2693
We address novel features of deep inelastic lepton scattering on nuclei at small Bjorken variable xBj. In this regime the lepton-nuclear cross section involves the interference between the standard lepton-quark scattering amplitude for the deep inelastic scattering (DIS) process on a single nucleon and a two-step process where diffractive scattering on a first nucleon combines with the amplitude for DIS on a second nucleon. The phases associated with the t-channel exchanges to the diffractive amplitude can produce either a destructive or constructive quantum-mechanical interference of the one-step and two-step amplitudes. This provides a mechanism regulating the respective amounts of shadowing suppression and anti-shadowing enhancement at low xBj. Furthermore, the standard leading-twist operator product and handbag diagram analyses of the forward virtual Compton amplitude on the nucleus are inapplicable, barring a conventional probabilistic interpretation. A main observable consequence is the impossibility of extracting momentum and spin sum rules from nuclear structure functions. We present numerical predictions supporting this picture and test them against DIS neutrino-nucleus and charged-lepton-nucleus scattering data.