quark transverse momentum in longitudinal nucleon structure
DESCRIPTION
Quark Transverse Momentum in Longitudinal Nucleon Structure. By Daniel Koch. With Wally Melnitchouk Rolf Ent Pedro Jimenez-Delgado. Outline. Motivation Past Models Current Theoretical Models Comparison With Data Future Work. Motivation. - PowerPoint PPT PresentationTRANSCRIPT
QUARK TRANSVERSE MOMENTUM IN LONGITUDINAL NUCLEON STRUCTURE
By Daniel Koch
With Wally MelnitchoukRolf EntPedro Jimenez-Delgado
OUTLINE Motivation Past Models Current Theoretical Models Comparison With Data Future Work
MOTIVATION Understand the 3-D structure of the nucleon
Longitudinal momentum fraction x
kT , the primordial transverse momentum
Expected that R, , is particularly sensitive to quark transverse momentum
1972, Feynman model
EARLY ATTEMPTS TO INCORPORATE KT IN QPM
From the early QPM (Quark Parton Model), for small kT2
Generalized QPM, with arbitrary kT2
Inconsistent treatment of 1/Q2 corrections
Hwa, Matsuda, Roberts, Z.Phys.C1,279(1979)
KINEMATICS Breit Frame:
is the transverse momentum dependent PDFwhere
TMD PDF
Eg. Gaussian form
Normalization of TMD PDF
In general, x and kT dependence may be coupled
Usually one assumes factorizable distribution
From factorizable model,
Flavor dependence
No longer has kT dependence in the denominator
Additional x dependence
RESULTS Comparison of Models with Data on R
Our model matches more closely to Feynman’s
The model favors a small value for the quark mass
X DEPENDENCE AT CONSTANT Q2
The data suggests a much stronger x dependence than our model
Our model shows some correct x dependence , unlike Hwa et al. and Feynman
Our model suggests a value for between 0.1 ~ 0.15 GeV2
CONCLUSIONS kT dependence is non-negligible
<kT2> is ~ 0.1 to 0.15 GeV2 based on our model
Hwa et al. model happens to accommodates larger values of <K>
x dependence from the data suggests need for flavor dependent <K> or a need for a non-factorizable form for the PDF
IN PROGRESS… Implement modern PDF sets
Perform (chi) ^2 fit for complete set of world’s data on R
Explore longitudinal structure function in SIDIS
Explore Models of R at low Q2
THANK YOU