The JLab Kaon Collaboration Homepage

NEW! The March 2002 kinematics are here and the new runplan for March 2002 is here. The new online analysis clues are here.

This page provides information on Jefferson Lab Hall A experiments E98-108, "Electroproduction of Kaons up to Q2 = 3 (GeV/c)2 " and E94-107, "High Resolution 1p-Shell Hypernuclear Spectroscopy". The spokespersons on the two experiments are:

O.K. Baker  Hampton
C.C. Chang  UMd
S. Frullani  INFN
F. Garibaldi  INFN
M. Iodice INFN
J. LeRose  JLab
P. Markowitz  FIU
T. Teresawa  Tohoku

The Experiments

Experiment E98-108 measures kaon production cross sections, picking a specific reaction mechanism via a separation of response functions in the exclusive H(e,e'K+)Y reaction. This experiment will measure how kaons are electromagnetically produced -- meaning which production mechanisms contribute and to what extent.

Current knowledge is unsatisfactory with no systematic separation of either the competing production mechanisms or the resulting response functions. Multi-parameter models based on hadron dynamics (QHD) have attempted to explain the existing data, but a wider kinematical region has to be accessed in order to constrain the models and the gKNY coupling constants. Three of the four unpolarized response functions will be separated over a range in Q2, W, and t.

The longitudinal and transverse response functions will be separated by detecting kaons along the direction of the virtual photon, where only these terms contribute to the cross section. For each Q2 kinematic the longitudinal and transverse responses will be separated at three different points in t. The separation of the longitudinal-transverse interference term will also be performed for selected kinematics, forming a sensitive test of the production model. The t-dependence of both the transverse response (at small |t|) and the full cross section will also be investigated, covering the transition from a semiphenomenological description in terms of mesons and baryons to a pQCD-based description in terms of quarks (or diquarks).

The Kinematics for January 2001 are Q2=2, 2.4 (GeV/c)2, -0.45< t<-1.0 GeV2, and W=1.85,1.9,1.95,2.13 GeV. The measured cross sections will be compared to both hadronic and subnucleonic reaction models. This will considerably extend the present electroproduction data. Incident beam energies of 3.395, 4.232, and 5.618 GeV will be utilized, along with the Hall A spectrometers, including both new diffusion aerogel counters.

Shift Signup:

Dimitri Margaziotis handled the shift signup for the E98-108 experiment. Please visit his web page to see the old shift schedule.

Run Coordinators:

The Run Coordinators for the experiment were:
Nilanga Liyanage   January 10-15
Pete Markowitz   January 25-31
Doug Higinbotham   March 12-24
Mauro Iodice   March 25-April 3
Joerg Reinhold   April 3-12
Pete Markowitz   April 13-??

The Proposals

The two proposals are available on the web in PDF format:
  • E98-108
  • E94-107
  • Meetings, Collaboration, Contacts

    You can access the archives for the experiment mailing list. To sign up, send mail to with the body text
       subscribe e98-108

    Working Documents

    Reference Material

    Links to related JLab Experiments

    E98-108 ran intertwined with E94-104. The link to E94-104 is:
  • . All of the commissioning data for E98-108 was taken during the beginning of E94-104. The runplan for the commissioning was part of the E94-104 runplan.
  • These experiments were or will be performed in Halls B and C at Jefferson Lab.

  • E91-016: Electroproduction of kaons and light hypernuclei
  • E93-021: The Charged Pion Formfactor
  • E89-009: Investigation of the Spin Dependance of the Lambda-Nucleon Effective Interaction in the P Shell
  • E99-006: Polarization observables in the 1H(e,e'K+)0

  • Pete Markowitz -