## Deep inelastic scattering processes and the parton model for hadrons

##### Authors

Kingsley, Roger Leon

##### Date

1973-08-03##### Awarding Institution

University of Cambridge

##### Author Affiliation

Department of Applied Mathematics and Theoretical Physics.

##### Qualification

Doctor of Philosophy (PhD)

##### Type

Thesis

##### Metadata

Show full item record##### Citation

Kingsley, R. L. (1973). Deep inelastic scattering processes and the parton model for hadrons (Doctoral thesis). https://doi.org/10.17863/CAM.16145

##### Description

One of the greatest puzzles of elementary particle physics is the
structure of the hadrons. Recent experiments at SLAC have found unexpectedly
large cross-sections for large momentum transfers from the electron in
high-energy electron-proton scattering, and this has led to the suggestion(l)
that these experiments are discovering the existence of point electromagnetic
charges within the proton. The supposed carriers of these point
charges hav~_ been called partons.
The cross-section measured in these experiments is that corresponding
to the diagram of fig. 1, under the assumption that only the lO1-J'est order
e,. ' >e
p ~ ~H Fig. 1
term in the expansion in p0i-TerS of the fine structure constant is significant.
In the laboratory system an electron of energy E is scattered off a proton
at rest, emerging at a scattering angle & .nth energy E:/, and only these
parameters of the scattered electron are measured, the final states H of
the hadronic system being ignored. The hadronic process is then parametrised
by the Lorentz invariants
and
y
",I:
(1.1)
(1.2)
2.
The experiments can be regarded as measuring the total cross-section for
scattering virtual photons on protons. This is described by a squared matrix
element summed over all hadronic states consistent with appropriate conservation
laws
~ < r-/JfA ( 0) I H(r1) < H(fJ/J'){o)0)
x. (277)1,. J(+J(r<-r-'t)
which can be written as ·thematrix element of a current commutator
Using current conservation we can write . .
•
Wr
'(f;1J:: (-/' + 'k;{) \IV;' ~)J) . .
+ (f - { ? ) ( ; - ~ 7' ) t1( ~ V),
The ~caling hypothesis(2) states that, in the limit
(1.3)
-v -7 c-o (1.6)
r. \ == 2-Y fixed, vv -7
called the Bjorken limit, the structure functions have scaling behaviour
w (~~))) ~f;(w)
)l VV2- (CY~Y) ~F; (w). (1.8)
In other words it is suggested that, at large V and CV~ , W, and
y vK should become functions only of the dimensionless quantity W •